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ASS OC IAT IO N B ETWEEN O RAL HEALTH L IT ERAC Y AND P AT IENT -C ENTRED AND

C L IN IC AL O UTCO MES

by

Dania Abdulelah Sabbahi

A thesis submitted in conformity with the requirements

for the degree of Doctor of Philosophy

Graduate Department of Dentistry

University of Toronto

© Copyright by Dania Abdulelah Sabbahi (2013)

ii

Association between Oral Health Literacy and Patient-Centred and

Clinical Outcomes

Dania Abdulelah Sabbahi

Doctor of Philosophy

Graduate Department of Dentistry

University of Toronto

2013

Abstract

During the last decade, oral health literacy (OHL) has received significant attention as an

important factor that might affect oral health outcomes. Few published instruments are

available to measure OHL. Most of these instruments focus on measuring the functional OHL

(word recognition, comprehension and numeracy skills) with no attempt in the literature to

measure other levels of oral health literacy (communicative and critical OHL). The aim of this

PhD thesis was to cover some of the deficiencies in OHL research. A conceptual framework for

the factors or outcomes affecting or affected by OHL was developed. Several factors and

outcomes were included in the model, including: socio-demographics, dental usage and oral

health behaviour variables, self-perceived oral health status, dental knowledge, oral health

impact, quality of patient-dentist communication, caries experience and periodontal condition.

In the first part of the project, a new communicative and critical OHL instrument (CCOHLI)

was developed. CCOHLI displayed high internal consistency and good test-retest reliability.

Construct validity of the CCOHLI was established against other health literacy and OHL

instruments. Predictive validity was established by significant associations with oral hygiene

behaviours, self-perceived oral health status, and caries experience at a multivariate level.

iii

The aim of the second part was to confirm the predictive and construct validity of the

previously developed and validated OHL instrument (OHLI). The construct validity of the OHLI

was confirmed against medical and dental word recognition tests. The predictive validity of the

OHLI was confirmed with significant associations with some of the socio-demographics, oral

health knowledge, prevalence of oral health impact, and caries experience at multivariate level.

In the third part, the validity of a set of questions as a quick tool to identify patients with

limited OHL was established. These screening questions can provide a rapid and inexpensive

way to identify patients with limited oral health literacy in a busy clinical setting or to conduct

large-scale studies.

The fourth part shed light on patient-dentist communication as one of the factors that

might be influenced by the level of OHL. This area requires special attention in order to improve

the quality of the communication process.

iv

Dedication

v

Acknowledgments

Praise and gratitude to ALLAH, Almighty, without whose gracious help it would have been

impossible to accomplish this work.

First and foremost, I would like to express my gratitude to my supervisor, Dr. Herenia P.

Lawrence, whose expertise, understanding, and time, added considerably to my graduate

experience. I appreciate her support, advice, and guidance throughout my master and

doctorate journey, which lasted more than 7 years.

Special thanks go to my co-supervisor, Prof. Hardy Limeback, for his expertise,

understanding, and support from the beginning of this project. His insight, advice and guidance

contributed significantly to this project.

Next, I wish to thank my thesis advisory committee member, Dr. Cameron Norman, for the

time he provided throughout this project. He provided insights that challenged my thinking, and

substantially helped in improving the quality of this finished product.

Specials thanks also go to my family for the support they provided through my entire life, and

very special thanks go to my husband, love and best friend, Mohammed, and my sons,

Abdullah, Ibrahim and Yousuf, without their love, encouragement, on-going support and

sacrifices throughout this process, I would not have finished my graduate programs. A special

welcome goes to my new bundle of joy, Abdulelah, who was there hiding for the last 9 months

of my project and joined us just after defending my dissertation.

Finally, I wish to thank the respondents of my study (who remain anonymous for

confidentiality purposes). Their participation, comments and insights created an informative

and interesting project with opportunities for future work.

In conclusion, I recognize that this research would not have been possible without the

financial support of the King Abdulaziz University, Saudi Arabia. This support is duly

acknowledged.

vi

TABLE OF CONTENTS

Page no.

Abstract ii

Dedication iv

Acknowledgments v

Table of content vi

List of tables viii

List of figures xii

List of appendices xiii

List of abbreviations, symbols, and nomenclature xiv

Introduction and overview 1

1.1. Historical background and definition 2

1.2. A conceptual framework for health literacy 6

1.3. Factors affecting health literacy 7

1.4. Factors contributing to limited health literacy 10

1.5. Functional health literacy 11

1.6. Measuring health literacy 13

1.7. Measuring communicative and critical health literacy 15

1.8. Limitations of health literacy 16

1.9. Health literacy in North America 17

1.10 Oral Health Literacy 19

1.11 Oral health literacy framework 20

1.12 Oral health literacy studies 21

1.13 Oral health literacy instruments 22

1.14 Association between oral health literacy and oral health outcomes 26

Objectives 51

Material and Methods 53

Study protocol 54

Project parts 65

Part 1: Development and Validation of Critical and Communicative Oral Health

Literacy Instrument (CCOHLI) 65

vii

Part 2: Further Validation of Oral Health Literacy Instrument (OHLI) 65

Part 3: Validation of Screening Questions for Limited Oral Health Literacy 74

Part 4: Oral Health Literacy and Dentist-Patient Communication 76

Results 82

Discussion 194

Strengths and Limitations 212

Summary 21

References 222

Appendices 232

viii

List of tables

No. Description Page no.

Table 1 Oral Health literacy instruments 28

Table 2 Oral Health literacy studies (other than instruments) 37

Table 3 Relationships between Oral Health Literacy and some of the Socio-

demographic and Oral Health Outcome Variables 47

Table 4 The duration for the tests and questionnaires that were used in the

project 59

Table 5 Details of literacy and knowledge tests 60

Table 6 Variables used in the statistical analysis and their coding 71

Table 7 Variables that were used in the statistical analysis and their coding 80

Table 8 Sample characteristics 93

Table 9 Frequency of responses for the test of Communicative and Critical Oral

Health Literacy (CCOHLI) 96

Table 10 Subscales and total Mean scores for the test of Communicative and

Critical Oral Health Literacy (CCOHLI) 97

Table 11 Subscales and total Mean scores for OHLI and its components 98

Table 12 Subscales and total Mean scores for Oral Health Knowledge test 99

Table 13 Subscales and total Mean scores for REALD-30 and REALM scores 100

Table 14 Spearman’s correlation between CCOHLI and OHLI and their components,

knowledge test REALM and REALD 101

Table 15 Association between OHLI reading score and some predictors 102

Table 16 Association between OHLI numeracy score and some predictors 103

Table 17 Association between OHLI total score and some predictors 104

Table 18 Association between CCOHLI score and some predictors 105

Table 19 Association between REALD-30 score and some predictors 106

Table 20 Association between REALM score and some predictors 107

Table 21 Association between oral health knowledge test score and some

predictors 108

Table 22 Chi square analysis between OHLI and some predictors 109

Table 23 Chi square analysis between CCOHLI and some predictors 110

Table 24 Chi square analysis between REALD-30 and some predictors 111

Table 25 Chi square analysis between REALM and some predictors 112

Table 26 Association between health literacy or oral health literacy level and oral

health knowledge test score 113

Table 27 Frequency of responses to individual OHIP-14 items and mean items

score 114

Table 28 Prevalence, extent and severity of impacts by OHIP-14 subscale and total

score 115

Table 29 Spearman’s correlation between CCOHLI and OHLI and their components,

REALM and REALD and OHIP-14 and its domains 116

ix

Table 30 Chi square analysis between oral health literacy level and prevalence of

oral impacts (fairly often/very often) (as measured by OHIP-14) 117

Table 31 DMFT descriptive statistics 118

Table 32 Spearman’s correlation between DMFT and CCOHLI and OHLI and their

components, knowledge test, REALM and REALD 119

Table 33 Association between CCOHLI Level and the DMFT data 120

Table 34 Association between OHLI Level and the DMFT data 121

Table 35 Association between REALD-30 Level and the DMFT data 122

Table 36 Association between REALM Level and the DMFT data 123

Table 37 Prevalence of periodontal pockets by highest score 124

Table 38 Chi square analysis between oral health literacy level and the prevalence

of the periodontal pockets depths (cut-off point at 3mm) 125

Table 39 Logistic regression model for CCOHLI Level (inadequate) 126

Table 40 Logistic regression model for OHLI Level (marginal or inadequate) 127

Table 41 Logistic regression model for REALD-30 Level (marginal or low) 128

Table 42 Reliability test for Communicative and Critical Oral Health Literacy

Instrument (CCOHLI) 132

Table 43 Intra-class Correlation Coefficient (ICC) for Communicative and Critical

Oral Health Literacy Instrument (CCOHLI) 133

Table 44 Frequency of responses (%) to limited oral health literacy screening

questions 134

Table 45 Areas under the receiver operating characteristic curve and 95% CI for the

oral health literacy screening questions (using OHLI level) 135


oral health literacy screening questions (using CCOHLI) 136


oral health literacy screening questions (using REALD-30) 137

Table 48 Performance of oral health literacy screening questions for detecting

inadequate or marginal oral health literacy using OHLI 138

Table 49 Performance of oral health literacy screening questions for detecting

inadequate oral health literacy using CCOHLI 139

Table 50 Performance of oral health literacy screening questions for detecting low

or marginal oral health literacy using REALD-30 140

Table 51 Frequency of responses to Interpersonal Processes of Care in Diverse

Populations Questionnaire (IPC) 148

Table 52 Mean scores for Interpersonal Processes of Care in Diverse Populations

Questionnaire (IPC) subscales 150

Table 53 Percentage of participants reporting poor and good Interpersonal

Processes of Care (IPC) 151

Table 54 Association between IPC general clarity score and some predictors 152

Table 55 Association between IPC elicitation and responsiveness score and some 153

x

predictors

Table 56 Association between IPC explanation of the condition score and some

predictors 154

Table 57 Association between IPC explanation of process of care score and some

predictors 155

Table 58 Association between IPC explanation of self-care score and some

predictors 156

Table 59 Association between IPC empowerment score and some predictors 157

Table 60 Association between IPC decision-making score and some predictors 158

Table 61 Chi square analysis between IPC general clarity score and some predictors 159

Table 62 Chi square analysis between IPC elicitation and responsiveness and some

predictors 160

Table 63 Chi square analysis between IPC explanation of the condition level and

some predictors 161

Table 64 Chi square analysis between IPC explanation of process of care and some

predictors 162

Table 65 Chi square analysis between IPC explanation of self-care and some

predictors 163

Table 66 Chi square analysis between IPC empowerment and some predictors 164

Table 67 Chi square analysis between IPC decision-making and some predictors 165

Table 68 Summary table summarizing the results from table 54 to table 67 166

Table 69

Spearman correlation between Interpersonal Processes of Care in Diverse

Populations Questionnaire (IPC) subscales and CCOHLI and OHLI and their

components, REALD, REALD and knowledge test

167

Table 70 Association between different oral health literacy tests and knowledge

test scores and IPC general clarity level 168


test scores and IPC elicitation and responsiveness level 169


test scores and IPC explanation of the condition level 170


test scores and IPC explanation of process of care level 171


test scores and IPC explanation of self-care level 172


test scores and IPC empowerment level 173


test scores and IPC decision-making level 174

Table 77 Chi square analysis between oral health literacy level and IPC general

clarity level 175

Table 78 Chi square analysis between oral health literacy level and IPC elicitation 176

xi

and responsiveness level

Table 79 Chi square analysis between oral health literacy level and IPC explanation

of the condition level 177


of process of care level 178


of self-care level 179

Table 82 Chi square analysis between oral health literacy level and IPC

empowerment level 180

Table 83 Chi square analysis between oral health literacy level and IPC decision-

making level 181


Table 85 Logistic regression model for IPC general clarity level (poor) 183

Table 86 Logistic regression model for IPC elicitation and responsiveness level

(poor) 184

Table 87 Logistic regression model for IPC explanation of the condition level (poor) 185

Table 88 Logistic regression model for IPC explanation of process of care level

(poor) 186

Table 89 Logistic regression model for IPC explanation of process of self-care level

(poor) 187

Table 90 Logistic regression model for IPC empowerment level (poor) 188

Table 91 Logistic regression model for IPC decision-making level (poor) 189


Table 93

Frequency of responses to oral health related barrier questions and to

questions about the pattern of communication between patients and

undergraduate students

191

Table 94

Frequency of responses to oral health related barrier questions and to

questions about the pattern of communication between patients and

undergraduate students (subdivided based on the student year)

192

xii

List of figures


Figure 1 Conceptual framework for literacy and health research 17 6

Figure 2 Determinants of Literacy 17 7

Figure 3 Oral Health Literacy Framework derived from the 2004 IOM Report on

Health Literacy 4

20

Figure 4 New patient screening and examination protocol at the Faculty of Dentistry

55

Figure 5 Conceptual framework for association between oral health literacy and different factors and outcomes

204

xiii

List of appendices


Appendix I University of Toronto Research Ethics Committee’s Approval 233

Appendix II Information sheet and consent form 235

Appendix III Personal information questionnaire 239

Appendix IV Health literacy screening Questions 244

Appendix V Interpersonal Processes of Care in Diverse Populations Questionnaire (IPC)

246

Appendix VI Oral Health Impact Profile (OHIP-14) 249

Appendix VII Dental knowledge test 252

Appendix VIII Oral Health Literacy Instrument for adults(OHLI) 257

Appendix IX Rapid Estimate of Adult Literacy in Medicine (REALM) 273

Appendix X Short version of Rapid Estimate of Adult Literacy in Dentistry (REALD-30)

276

Appendix XI Communicative and Critical Oral Health Literacy Instrument (CCOHLI)

278

Appendix XII Questionnaire about student-patient communication and barriers encountered by the patient

280

xiv

List of abbreviations, symbols, and nomenclature

ADD Attention Deficit Disorder

ALLS Adult Literacy and Life Skills survey

AMA American Medical Association

AUROC The areas under the ROC curve

CCOHLI Critical and Communicative Oral Health Literacy Instrument

CI Confidence intervals

CIHR Canadian Institute of Health Research

CPHA Canadian Public Health Association

DMFT Decayed, Missing and Filled (permanent teeth index)

DNS Dental Neglect Scale

ECOHIS Early Childhood Oral Health Impact Scale

GSES General Self-Efficacy Scale

HKREALD-30 Hong Kong Rapid Estimate of Adult Literacy in Dentistry

HKREALD-99 Hong Kong Rapid Estimate of Adult Literacy in Dentistry

IALSS International Adult Literacy Survey

ICC Intraclass correlation coefficient

IOM Institute of Medicine

IPC Interpersonal Processes of Care in Diverse Populations Questionnaire

LR Likelihood Ratio

NIDCR National Institute of Dental and Craniofacial Research

NVS Newest Vital Sign

OHIP-14 Oral Health Impact Profile (short-form)

OHL Oral health literacy

OHLI Oral Health Literacy Instrument

OH-LIP Oral Health Literacy Inventory for Parents

OHQofL Oral Health-related Quality of Life

PCC Pearson’s Correlation Coefficient

REALD-30 Rapid Estimate of Adult Literacy in Dentistry-30

REALD-99 Rapid Estimate of Adult Literacy in Dentistry-99

REALM Rapid Estimate of Adult Literacy in Medicine

REALM-D Rapid Estimate of Adult Literacy in Medicine and Dentistry

REALM-R Shortened version of the REALM (revised)

ROC Receiver Operating Characteristic

SD Standard deviation

TOFHLA Test of Functional Health Literacy of Adults

TOFHLiD Test of Functional Health Literacy in Dentistry

TS-REALD Two-Stage REALD

WHO World Health Organization

1

Introduction

and

Overview

2

1.1. Historical background and definition

The term “health literacy” was first used by Simonds (1974) in his paper “Health Education

as Social Policy.” The paper described how health information is shaped by the educational

system, health care system, and mass communications1. This early use of “health literacy”

suggests a link between health literacy and health education, which implies that any failure in

health education can contribute to poor health literacy; in other words, health literacy is an

outcome of health education. Today, demands for health literacy have increased due to

advancements in medical science, changes in the availability and quality as well as delivery of

health information, and patients’ responsibility for self-care in a complex health care system.

This culture of high health literacy demands has led to an increase in health literacy problems2,

for example, where over-the-counter drugs are concerned, parents are required to read and

calculate a child’s weight in relation to his/her age to determine the proper dosage given.

Because health literacy is still an emerging concept, different definitions of health literacy

have evolved, each of which has its own scope. One of these definitions was developed by The

American Medical Association (AMA) which defines health literacy as “the constellation of skills,

including the ability to perform basic reading and numerical tasks required to function in the

health care environment”3. The Joint Committee on National Health Education Standards

defines it as “the capacity of individuals to obtain, interpret and understand basic health

information and services and the competence to use such information and services in ways

which enhance health”. Another definition for health literacy was developed by Ratzan and

Parker and was adopted for use in Healthy People 2010. It is defined as “the degree to which

individuals have the capacity to obtain, process and understand basic health information and

services needed to make appropriate health decisions”2;4

In their definition of health literacy, the AMA confines the scope of health literacy to the

health care sector. On the other hand, the Joint Committee on National Health Education

Standards extended the concept of health literacy beyond the health care sector to the

education sector to maintain a focus on the level of the individual’s knowledge and skills.

However, both failed to take into consideration the complexity of various health contexts.

Finally, the Healthy People 2010 definition for health literacy is based on the concept that

3

health literacy should encompass a variety of health contexts with which an individual may

interact for health information4. These “health contexts” include individuals, media, the

marketplace, and governmental agencies that provide basic health information.

According to the World Health Organization (WHO), health literacy has been defined as “the

cognitive and social skills which determine the motivation and ability of individuals to gain

access to, understand, and use information in ways which promote and maintain good health”5.

This definition is distinct from others in that it focuses not only on cognitive skills but also

incorporates social skills, which are required to implement decisions into practice. In addition, it

refers to both motivation and ability6. Based on this definition, Nutbeam7 proposed a model of

health literacy which includes three levels:

Functional/basic literacy: refers to basic skills in reading, writing, and

comprehension to be able to function effectively in everyday situations.

Communicative/interactive literacy: refers to skills required to participate in

everyday activities actively, to extract information and derive meaning from

different forms of communication, and to apply new information to changing

circumstances.

Critical literacy: refers to cognitive and social skills required to analyze information

critically and use it to exert greater control over different situations through

individual and collective action to address the social, economic and environmental

determinants of health.

Similarly, the Canadian Public Health Association (CPHA) Expert Panel on Health Literacy has

incorporated all the above three levels into its definition: “Health literacy is the ability to access,

understand, evaluate and communicate information as a way to promote, maintain and

improve health in a variety of settings across the life course.” 8

The term functional health literacy means being able to apply literacy skills to health-related

materials such as prescriptions, appointment cards, medicine labels, and directions for home

care9. However, this functional definition is narrow and does not focus on the skills required to

communicate, obtain and critique health information from various resources. These other skills

are the focus of communicative/interactive and critical health literacy.

4

Communicative/interactive health literacy requires more advanced cognitive and literacy

skills that, together with social skills, can be used to assist a person in active participation in

everyday activities, extract information and derive meanings from different forms of

communication, and apply new information to changing circumstances. In contrast, critical

health literacy requires more advanced cognitive skills, which together with social skills, can be

applied to critically analyse information, and to use this information to exert greater control

over life events and situations and take social and political action at the community level as well

as individual action at the personal level.

In 2005, Schulz and Nakamoto provided a three-tiered concept of health literacy10. They

conceptualize health literacy as declarative knowledge (factual knowledge related to health

issues to be able to learn how to approach a health condition), procedural knowledge (the

ability to apply factual knowledge and use health information in a specific context) and

judgment skills (the ability to judge based on factual knowledge necessary to deal with novel

situations).

Jordan et al. took an explorative approach to define health literacy from the patient

perspective11. The following skills are identified by the authors as necessary skills to participate

actively in the health care system: functional literacy skills; critical self-examination and

knowing when it is necessary to get help from health-care services; the ability to know where to

seek the health information; verbal communication skills to describe health issues and

understand the response and instructions from the health professional; skills to retain and

process information skills to comprehend and extract meaning from the provided health

information; assertiveness; and application skills to follow instructions and implement

procedures to modify lifestyle and effectively address health issues.

In a recent publication, Frisch et al. looked at the domains of (new) media literacy,

information literacy, science/scientific literacy, cultural literacy and civic/political literacy to

retrieve dimensions included in the concepts of these domains and to understand how health

literacy research can benefit from these dimensions12. Their review revealed seven distinct

dimensions to be included in the domain of health literacy: functional literacy, factual

knowledge, procedural knowledge, awareness, a critical dimension, an affective dimension and

attitudes.

5

All previous definitions reveal the multidimensionality of the health literacy and the lack of

agreement about which dimensions and concepts to include in the health literacy concept. This

lack of consensus hinders the development of validated measures of health literacy that reflect

its multidimensionality13.

6

1.2. A conceptual framework for health literacy

A conceptual framework for health literacy was designed by the Institute of Medicine (IOM)

(Figure 1), which places literacy as the foundation for health literacy4 . “Literacy” is defined as

“the ability to read, write, communicate and comprehend”14. From this definition, it is obvious

that a person’s level of literacy is determined by the size of his or her vocabulary and how well

he or she clearly understands the definitions of words15. In 1991, the U.S. National Literacy Act

defined literacy as “an individual’s ability to read, write, and speak English, and compute and

solve problems at levels of proficiency necessary to function on the job and in society, to

achieve one’s goals, and develop one’s knowledge and potential”16.

Figure 1: Conceptual framework for literacy and health research17

7

DeterminantsDeterminants

EducationEducation

Early Child DevelopmentEarly Child Development

AgingAging

Personal CapacityPersonal Capacity

Living/Working ConditionsLiving/Working Conditions

GenderGender

CultureCulture

DeterminantsDeterminants

EducationEducation

Early Child DevelopmentEarly Child Development

AgingAging

Personal CapacityPersonal Capacity

Living/Working ConditionsLiving/Working Conditions

GenderGender

CultureCulture

1.3. Factors affecting literacy or “Determinants of Literacy”

There are many factors affecting literacy, some of which are considered determinants of

health. A Canadian Institute of Health Research (CIHR) report on literacy and health in Canada,

produced by Irving Rootman and Barbara Ronson in 2003, provides an excellent overview of

factors affecting literacy17. These factors are described below (Figure 2):

Figure 2: Determinants of literacy17

1. Education:

In general, schools differ in literacy level of their students. There is a strong relation

between education and literacy18. However, they are not perfectly correlated19.

2. Early Childhood Development:

It is easier to learn during early childhood, for example, it is easier to acquire a language

from birth till three years. This task becomes more difficult as the child gets older20.

8

3. Aging:

Several factors might be attributed to limited health literacy in the elderly:

Elderly people have more reading difficulties compared to younger people even after

adjusting for years of school completed and cognitive impairment21. In addition, an individual

might lose reading skills over time if he or she does not read a lot17.

Loss of hearing or sight might worsen the understanding and learning abilities of elderly

persons.

It is not uncommon for elderly people to have mental or physical disabilities, which might

affect their understanding and learning abilities.

Some researchers have linked the low health literacy among the elderly with higher rate of

hospitalization, lower mental health scores, poorer self-reported health, and less use of the

preventive care22-24.

4. Personal Capacity:

Some conditions can affect learning ability, for example:

Sight and hearing problems.

Genetic conditions that might affect learning ability (e.g., Down Syndrome).

Attention Deficit Disorder (ADD).

Learning disabilities.

Subjects with these conditions should receive special attention, especially during their

childhood.

5. Living and working conditions:

Lower health literacy was found to be associated with low incomes19.

Children of parents with reading problems are more likely to have reading problems

themselves25.

Violence and abuse tend to decrease learning abilities for both adults and children26.

Work environments might affect learning abilities of workers17.

9

6. Gender:

In less developed countries, women have lower literacy level compared to men27.

In all the countries participated in International Skills Assessment (PISA), girls tend to

score better in measurements of literacy than boys28.

In Canada, literacy skills are better in young girls compared to young boys29.

In Canada, Women displayed advantage in the prose literacy skills, while men performed

better in the document and numeracy literacy skills 30.

7. Culture and language:

In Canada, lower literacy has been reported among Francophones, Aboriginal peoples and

immigrants. This lower literacy is related to language and cultural barriers 31.

10

1.4. Factors contributing to limited health literacy among patients

Several other factors may affect a patient’s health literacy32. These include:

1. Factors related to the health care system:

Complexity of new medications and treatments.

Health providers have less time to spend with patients.

Increasing demands for self-care procedures increases the need for better

health literacy, since most of the self-care home procedures need more

understanding by patients.

Fragmentation of services between different specialties and lack of proper

communication between them which makes the patient act as an “inter-physician

messenger”, a difficult role for patients with limited literacy skills and poor

understanding of medical concepts.

Complexity of insurance and health-related forms or documents increases the

difficulty of understanding them.

2. Factors related to the providers:

Health care providers tend to use terms that patients may not understand. Furthermore,

they often spend little time ensuring that the patient understands the information.

3. Factors related to the patient:

Patients with limited health literacy tend to have low self-empowerment and are ashamed

of their limitations, which might affect their ability to interact with the health care system and

health care providers.

It has to be emphasized that each of the above factors can’t be isolated and there are

interactions among them which add to the complexity of the health literacy. It is obvious that

the patients can’t be blamed alone for the health literacy problems and that all other factors

related to the provider and health system should be addressed in order to improve the patient

health literacy level.

11

1.5. Functional health literacy

The term health literacy, as mentioned above, is used for describing situations and settings

in which individuals or groups receive health-related information and messages. If these people

successfully function in the complex and multidimensional health care environment and use

health information, they are considered to have functional health literacy, which includes the

ability to successfully complete tasks such as reading and comprehending prescriptions and

appointment slips, and completing forms on financial eligibility1;33. Furthermore, functional

health literacy involves accessing, understanding and applying health information received from

other non-clinical sources such as newspapers, magazines, television programs, and websites34.

In order to have functional health literacy, many skills are needed, including:

Skills and ability of traditional literacy.

Abilities in prose, document, and quantitative literacy.

Ability to engage in two-way communications.

Skills in media literacy and computer literacy.

Motivation to receive health information.

Freedom from impairments and/or communicative assistance from others.

Traditional, prose, document, and quantitative literacies are all necessary in order to have

functional health literacy but they are still not sufficient for overall functional health literacy.

The National Adult Literacy Survey assessed five domains necessary for functional health

literacy including reading, writing, numeracy, speaking and listening. When a person is able to

engage in a conversation by speaking and listening, known as “two-way communication ability”,

he/she will be able to clearly and accurately express his/her physical, mental and emotional

status to health care providers, and to understand and process health information expressed by

the health care provider35.

Currently, new abilities and skills are needed for overall functional health literacy because

health information comes from so many different sources. One of these abilities or skills is

media literacy, which is defined as “the ability to develop an informal and critical understanding

of the nature of mass media, the techniques used by them and the impact of those

techniques”36. Another new skill is computer literacy which is defined as “an understanding of

12

the concept and terminology and operations related to general computer use and the essential

knowledge needed to function independently with a computer. This functionality includes being

able to solve and avoid problems, adapt to new situations, keep information organized, and

communicate effectively with other computer literate people”37. These skills are needed for

accessing, understanding, and applying health information since so much of the health

information available today comes via television, radio and the internet. In other words, the

ability to seek, find, understand and use health information provided through electronic

sources such as the internet, is known as eHealth literacy. This eHealth literacy needs six

different literacies. Norman and Skinner (2006) developed a model for eHealth literacy dividing

those six literacies into two central domains: analytical (traditional, media, and information

literacies) and context-specific (computer, scientific, and health literacies) and called it “The Lily

Model”38. People who lack media, computer and/or eHealth literacy may be more likely to

misunderstand essential health information available through these channels of

communication37;39.

These new conceptualizations cover most of the medium by which health resources are

presented within the modern health information environments. In this modern dynamic

environment, basic health literacy skills are not enough and more skills are needed in order to

utilize the health resources efficiently.

Another attribute necessary for overall functional health literacy is what people believe

about health information they have received and how they react to it. Lack of motivation to

receive or act on health information can be a barrier to functional health literacy40.

Physical and/or mental impairment also can affect functional literacy and influence overall

literacy related skills and abilities34.

13

1.6. Measuring basic/functional health literacy

Traditionally, researchers and clinicians used patients’ education levels as an indicator for

their literacy skills41-45. Although education is highly correlated with reading level and the level

of functional literacy, educational level alone cannot predict literacy41;45;46. A person who

completed high school or even a higher level of education could still have poor literacy skills

and vice versa21;41;45;46.

Subsequently, researchers and clinicians have realized the need for an alternative approach

to assess individuals’ literacy. Hence, informal and formal methods were developed for this

purpose. One of the informal methods is described as observing the patient’s behaviour when

handling literacy tasks in the clinical setting, such as filling out forms incompletely, misspelling

many words, asking for help, becoming angry and uncomfortable with having to fill out the

forms or leaving the clinic before completing the forms46. Another informal way to test health

literacy is asking the patient to bring his/her medication to the clinical visit; those who identify

the medications by opening the bottle and looking at the pills rather than reading the label may

lack the skills to read and understand prescription labels. Also, those patients who do not know

why they are taking the medication probably have low health literacy47.

On the other hand, formal and more accurate way of assessing health literacy can be

achieved by using a validated instrument. Multiple instruments were developed during the last

two decades to measure health literacy. In a recent review article48, 19 health literacy

instruments were identified. Twelve instruments were original and 7 were short-form versions

or adaptations of an original instrument. Three measurement approaches were identified:

direct testing of individual abilities, self-report of abilities, and population-based proxy

measures. Most of these instruments used two types of standardized reading tests, “Reading

Recognition Tests” and “Reading Comprehension Tests”, in health literacy testing.

Reading recognition tests are useful predictors for general reading ability. In fact, reading

recognition tests are the most commonly used tests to identify low-level readers in the health

care setting, because they are the easiest and quickest type of instruments to administer and

score43.

14

Reading comprehension tests assess the patient’s ability to read and understand text

written at different levels of difficulty43;44. These types of tests need more time and skills to

administer than word recognition tests.

The most commonly used reading recognition test in the health care setting is the Rapid

Estimate of Adult Literacy in Medicine (REALM)49, which was first developed in 1991 and revised

in 1993. This test was specifically designed to screen for low literacy in the health care

setting43;44;50. It is composed of common medical words and terms for body parts and illnesses.

The words were chosen from written material commonly given to patients in primary care

settings. The test is for adults only, needs minimal training to administer, and takes only about

2-3 minutes to complete50. The primary limitation of this test is that it does not give a point

estimate grade; rather, it only assigns a grade-range estimate47.

In 2002, a shortened version of the REALM (REALM-R) was designed as a rapid screening

instrument to identify patients at risk for poor literacy in health care settings51. It is composed

of 10 words derived from the original REALM, which contains three lists, each with 22 words.

The time required for the REALM-R including explanation and delivery is less than 2

minutes51;52.

On the other hand, the Test Of Functional Health Literacy in Adults (TOFHLA)9 is an example

of a reading comprehension test. This test has been used for health literacy research in medical

and community settings9;21;43;53. The TOFHLA consists of reading comprehension of “Cloze-style”

health care material in which 50 items are distributed through three selected passages, and 17

items are included in the numeracy section. Both sections are composed of actual material that

patients may receive in any health care setting. The TOFHLA is used only for adults, but unlike

the REALM, the original TOFHLA takes longer, usually between 18 and 22 minutes. Because of

its length, a shorter version of the TOFHLA was created with a 36-item reading comprehension

and a 4-item numeracy test. This shorter version of the test takes about 12 minutes or less to

administer and has been shown to have good internal reliability and validity53. Both English and

Spanish versions of this test are available4;47.

15

1.7. Measuring communicative and critical health literacy

All previously mentioned tests centered on measuring basic/functional health literacy, not

communicative and critical health literacy. Only two attempts to measure communicative and

critical health literacy have been reported in the literature, by a group of researchers in Japan.

They first developed a scale to assess communicative and critical health literacy in diabetic

patients54. Communicative health literacy was evaluated with five items assessing the extent to

which patients had extracted and communicated diabetes-related information since they were

diagnosed with the disease. Critical health literacy was evaluated by four items which were

used to assess the extent to which patients had critically analyzed the information and make

decisions. The second scale was designed to assess major components of communicative and

critical health literacy among Japanese office workers.55 The scale is composed of three

questions assessing communicative healthy literacy and two questions assessing critical health

literacy. The questions used to assess communicative health literacy asked whether the

participant would be able to collect health-related information from various sources, extract

the information he/she wanted, and understand and communicate the obtained information.

The questions used to measure critical literacy asked whether the participant considered the

credibility of the information and made decisions based on the health information obtained.

16

1.8. Limitations of health literacy testing

The health literacy instruments can be critiqued as follows:

Composition of underlying constructs and content varies widely across instruments and

content is focused primarily on reading recognition and comprehension, and

numeracy48.

Few of these instruments have been assessed for reliability48.

Scoring categories are poorly defined and clinical relevancy of the scoring is not

assessed48.

The responsiveness of health literacy instruments to different educational and health

promotion programs is not assessed in any of the studies48.

None of the instruments appear to fully measure a person’s ability to seek, understand,

and use health information48.

One of the limitations in health literacy testing is the lack of health literacy tests for

listening and speaking skills, which are also important for people seeking health

information and instructions17.

All developed health literacy tests cannot determine the cause or type of reading or

learning problems, and are used only to detect low literacy47. Determining the cause of

the low health literacy is crucial for addressing the deficiencies among the patients and

within the community in order to improve the health literacy for the individuals and the

community.

17

1.9. Literacy and Health literacy in North America

Literacy in the United States and Canada was documented based on the Adult Literacy and

Life Skills (ALLS) survey, which is also referred to as the International Adult Literacy Survey

(IALSS)31. In this survey, literacy was measured along three dimensions34;56:

1. Prose literacy was defined as “the ability to locate requested information within

written text documents such as editorials, news stories, poems and fiction, to

integrate disparate information presented in the texts, and to write new

information based on the texts”.

2. Document literacy was defined as “the ability to locate selected information on a

short form or graphical display of everyday information such as job applications,

transportation schedules, and maps, to apply selected information presented in

documents and to use writing to complete documents and survey forms that

required filling in information”.

3. Quantitative literacy (numeracy) was defined as “the ability to locate numbers

within graphs, charts, prose texts and documents; to integrate the quantitative

information from texts; and to perform appropriate arithmetic operations on text-

based quantitative data such as banks automated machines, and to understand bar

graphs and to complete an income tax form”.

The IALSS documented that the overall average level of literacy of North Americans is low.

The percentage of US adults (aged 16 to 65 living in households or prisons) with low prose,

document and numeracy literacy level (level 1) ranged between 20 and 27%. In Canada, 15-20%

of Canadian adults, age 16 to 65 have low prose, document and numeracy literacy (Level 1).

About 9 million (42%) of Canadian adults (aged 16-65) scored below Level 3 on the prose scale.

Moreover, about 43% and 50% of Canadian adults (aged 16-65) scored below Level 3 on the

document and numeracy scales, respectively. This percentage increases to 48% for the prose

and document literacy and 55% for the numeracy literacy if the people over the age 65 were

included30.

18

A large subset of IALSS survey items (350 items) contain broadly defined health content in

the following areas: health promotion and behaviors related to healthy habits; health

protection and accident prevention; disease prevention; health-care activities. A subset of these

items (191 items) was selected, with varying levels of difficulty representing a broad range of

health literacy-related tasks and contexts, to create a health literacy scale. This scale assigns a

health literacy score between 0 and 500 for each individual. Based on the assigned score,

different individuals were assigned a health literacy level ranging from 1 (lowest health literacy

level) to 5 (highest health literacy level). It is assumed that Level 3 (276–325) on the health-

literacy scale is the minimum requirement in order to participate fairly and fully in society57.

The average health-literacy score for Canadians was 258 with significant variations among

and within the provinces and territories. Approximately one out of every five adults aged 16–65

in Canada and the United States had very low health literacy levels (Level 1 and below)58.

Moreover, about 55% of Canadians aged 16 to 65 scored below Level 3 on the IALSS health

literacy scale and only one in eight adults (12%) over age 65 appears to have adequate health

literacy skills (Level 3 or above) 58. The Health literacy scores tended to decline with age and rise

with the level of formal education attained. Seniors, immigrants, especially those who do not

speak either French or English, and the unemployed possessed, on average, much lower levels

of skill in terms of health literacy57.

The impact of low health literacy on different outcomes was evaluated based on the IALSS

data. An association was found between health literacy and the individual’s social and

economic well-being. Canadians with the lowest health literacy skills were found to be less than

half as likely to have participated in a community group or to have volunteered; and more than

2.5 times as likely to be receiving income support when compared to those with skills at Levels

4 or 5 after removing the impact of age, gender, education, mother tongue, immigrant and

Aboriginal status. In addition, the results of the IALSS revealed an association between the

health literacy and some of the health outcomes. An association was found between the level

of health literacy and the self-perceived health status. Canadians with the lowest health literacy

skills were found to be more than 2.5 times as likely to be in fair or poor health when compared

to those with skills at Levels 4 or 5 after removing the impact of age, gender, education, mother

tongue, immigrant and Aboriginal status. Moreover, the low health literacy level was linked to a

high prevalence of some of the chronic diseases (diabetes and hypertension)57.

19

1.10. Oral Health Literacy

While the body of health literacy research has grown in recent years, little is known about

oral health literacy at present59. This might be attributed to the trend observed in the literature

that topics and concepts that start first in medical field will take time to be implemented in

dentistry. Because oral health is an integral part of overall health and well-being, it is important

that individuals have an adequate degree of oral health literacy. Oral Health Literacy has been

defined as “the degree to which individuals have the capacity to obtain, process and

understand basic oral health information and services needed to make appropriate health

decisions”60. This definition leads to Functional Oral Health Literacy, which encompasses

knowledge as well as the ability to use that knowledge in making appropriate decisions related

to oral health59. Individuals can receive oral health information in a variety of ways such as

texts, tables and graphs, as well as presentations by experts and oral health providers. This

indicates that oral health literacy encompasses far more than reading; it also involves writing,

numeracy, speaking and listening, similar to health literacy59.

20

1.11. Oral health literacy framework

A conceptual model of oral health literacy was suggested by a workgroup sponsored by the

National Institute of Dental and Craniofacial Research (NIDCR)59 (Figure 3). This model was

adapted from the Institute of Medicine (IOM) health literacy report4. This model suggests a

proposed explanation of the interplay among oral health literacy, culture and society, the

health system, and the education system, as well as their collective role in determining oral

health outcomes and costs. The workgroup called upon researchers to take oral health literacy

into account in order to create a comprehensive oral health care agenda59. Three types of

research are needed to set up this agenda:

Descriptive studies that provide the information needed to develop interventions.

Correlational studies that identify the relationship between oral health literacy and oral

health outcomes.

Interventional studies that test the efficacy of improved oral health literacy practices.

Figure 3. Oral Health Literacy Framework derived from the 2004 IOM Report on Health Literacy4

Oral Health LiteracyOral Health Literacy

Education SystemEducation System

Oral Health Oral Health

Outcomes Outcomes

and and

CostsCosts

Health SystemHealth System

Culture and SocietyCulture and Society

Figure 2Figure 2

Oral Health LiteracyOral Health Literacy

Education SystemEducation System

Oral Health Oral Health

Outcomes Outcomes

and and

CostsCosts

Health SystemHealth System

Culture and SocietyCulture and Society

Figure 2Figure 2

21

1.12. Oral health literacy studies

A thorough literature search in the Medline Database retrieved 15 clinical studies in which

oral health literacy was measured. Some of the characteristics of these studies can be

summarized as follows (more details about these studies can be found in Tables 1 and 2):

Twelve studies reported data of cohorts in the United States (10 from North Carolina, 1

from California and 1 from Washington). The rest of the studies (n=3) reported data from

Canada, Australia and China.

These 15 studies reported data representing 10 cohorts. Five studies61-65 reported different

outcomes for the same cohort; another two studies66;67 reported results about another

cohort, and the remaining 8 studies reported on 8 different cohorts.

Seven articles reported the development of instruments to measure oral health literacy as

the main goal while the rest of the articles aimed to examine the association between oral

health literacy and different socio-demographic and oral health outcomes variables.

Most of the studies that examined the association between oral health literacy and

different determinants and/or outcomes used REALD-30 (a word recognition test) to

measure oral health literacy.

22

1.13. Oral health literacy instruments

Although there are several instruments to assess health literacy, only a few published

instruments are available to measure oral health literacy. These instruments can be divided as

follows:

Functional Oral Health Literacy Instruments

o Word Recognition Instruments

Lee et al. (2007) developed a word recognition instrument to test health literacy in dentistry

based on the Rapid Estimate of Adult Literacy in Medicine (REALM)68. This oral health literacy

instrument is called the Rapid Estimate of Adult Literacy in Dentistry (REALD-30) and consists of

30 common dental words listed from the easiest to the most difficult. The REALD-30 was found

to have a good internal reliability (Cronbach α = 0.87) and its scores were significantly related to

the REALM and the TOFHLA scores, which indicates that the REALD-30 has good convergent

validity. The REALD-30 predictive validity was partially established since the instrument’s scores

were positively associated with oral health-related quality of life (p < 0.5) but not significantly

associated with self-perceived oral health status in a multivariate analysis.

Richman et al. (2007) added 69 new words to the REALD-30 to develop a longer version of

the word recognition dental health literacy instrument (REALD-99)67. Similarly, the REALD-99

had a good internal reliability (Cronbach α = 0.86) and its scores were significantly related to the

REALM, which indicates that the REALD-99 also has a good convergent validity67. The REALD-99

predictive validity was partially established since the instrument’s scores were positively

associated with oral health-related quality of life (p < 0.5) but not significantly associated with

self-perceived oral health status of the parents and their children in a multivariate analysis.

Although it was reasoned that a longer list of words would represent more components of oral

health and might provide a better chance of measuring oral health literacy more accurately,

both the REALD-30 and the REALD-99 performed similarly when tested. It should be mentioned

that the REALD-99 needed more administration time of about 5 minutes compared to 3

minutes for the REALD-30. It should also be noted that the REALD testing did not include an

assessment of the test-retest reliability.

23

Atchison et al. (2010) developed the Rapid Estimate of Adult Literacy in Medicine and

Dentistry (REALM-D)69, which consists of 66 medical terms from the REALM test and 18 dental

terms divided into 3 lists according to their difficulty. REALM-D showed a good internal

reliability (Cronbach α = 0.95). In addition, a high correlation was found between test and retest

scores (r=0.95). The criterion validity was evaluated by the degree of correlation between

REALM-D scores and the following variables: need help reading hospital forms, confidence in

filling out medical forms, and socio-demographic variables. Data analysis confirmed that

participants who reported always being confident filling out medical forms by themselves

and/or never needing someone to help them read hospital materials had significantly higher

REALM-D scores. In addition, race, educational level, and English as a main language were

predictive of health literacy.

Stucky et al. (2011) revised the REALD-3068 into a more efficient and easier to use two-

stage scale. Principles of item response theory and multi-stage testing were used to revise the

REALD-30 into the Two-Stage REALD (TS-REALD)64. Based on the participant’s score on the five-

item first-stage (i.e., routing test), one of three potential stage-two tests is administered: a four-

item Low Literacy test, a six-item Average Literacy test, or a three-item High Literacy test. TS-

REALD was found to have a good internal reliability (Cronbach α>0.85). Convergent validity was

established by reporting a significant correlation between TS-REALD and both REALD-30 and

Newest Vital Sign (NVS)70 scores. In addition, the TS-REALD was found to be predictive of

perceived impact of oral conditions on the quality of life, after controlling for educational level,

overall health, dental health, and a general health literacy level.

Wong et al. (2012) developed a Chinese version of the REALD71. The Hong Kong Rapid

Estimate of Adult Literacy in Dentistry (HKREALD-30) showed good to excellent Internal

reliability (Cronbach α = 0.84) and intraclass correlation coefficient (ICC) 0.83 and 0.79 for intra-

examiner and inter-examiner reliability, respectively. Concurrent validity was tested by

comparing the HKREALD-30 scores with the participants’ educational level, pattern of dental

visits and reading habits. Convergent validity was tested by examining the association between

HKREALD-30 and the Test of Functional Health Literacy in Dentistry (TOFHLiD)66 (translated to

Chinese). Data analyses revealed a significant association between HKREALD-30 and the

participants’ reading habits but not with their educational level and their pattern of dental

24

visits. HKREALD-30 was also highly correlated with TOFHLiD (translated) after controlling for the

participants’ characteristics.

o Reading comprehensive instruments

The first reading comprehensive oral health literacy instrument was the Test Of Functional

Health Literacy in Dentistry (TOFHLiD) which was developed by Gong et al. (2007) based on the

TOFHLA to test functional oral health literacy66. The TOFHLiD consists of a 68-item reading

comprehension test and a 12-item numeracy test. The reading comprehension section of the

TOFHLiD consists of three passages: instructions for a caregiver after fluoride varnish

application to their child’s teeth, a consent form for dental treatment, and a Medicaid rights

and responsibilities. The numeracy section has questions related to four topics: instructions for

fluoridated toothpaste use, a paediatric dental clinic appointment, prescription labels for

fluoride drops and prescription labels for fluoride tablets. The TOFHLiD had a low internal

reliability (Cronbach α = 0.63) and a strong convergent validity since the TOFHLiD scores were

highly correlated to the Rapid Estimate of Adult Literacy in Dentistry (REALD-99) scores. In

addition, The TOFHLiD showed a moderate ability to discriminate between dental and medical

literacy (moderate discriminant validity). The TOFHLiD’s predictive validity was partially

established since the instrument’s scores were positively associated with oral health-related

quality of life (p < 0.5) but not significantly associated with self-perceived oral health status of

the parents and their children in a multivariate analysis.

It should be noted that the TOFHLiD was developed to test parents’ oral health literacy skills

using items that are mostly encountered in the field of paediatric dentistry and that the

TOFHLiD testing did not include an assessment of the test-retest reliability.

Another instrument, the Oral Health Literacy Instrument (OHLI)72, was developed at the

University of Toronto (2007) in order to assess functional oral health literacy for adults. The

OHLI consists of two parts: reading comprehension and numeracy. The reading comprehension

section consists of 38 items divided between two passages, one on dental caries and the other

on periodontal disease. The numeracy section consists of 19 items to test the participant’s

ability to comprehend directions for taking some of the common prescriptions associated with

dental treatment, post-extraction instructions and clinical appointment cards.

25

Internal reliability of the OHLI was established with high Cronbach’s alpha values (>0.7). In

addition, test-retest reliability was established based on good intra-class correlation coefficient

(ICC) values (>0.6). Concurrent validity was demonstrated by a significant association between

OHLI scores and frequency of dental visits, while construct validity was demonstrated by

significant correlations between OHLI scores with TOFHLA scores and with the oral health

knowledge scores.

Another group of researchers came up with a new instrument that joined both ideas of

measuring functional health literacy reading comprehension and word recognition. Richman et

al. (2011) developed the Oral Health Literacy Inventory for Parents (OH-LIP)73 to evaluate 3

components of oral health literacy: word recognition; vocabulary knowledge; and

comprehension of 35 pediatric oral health terms. The items included in the OH-LIP were

selected from the REALD terms, a research instrument called Things to Know about Baby Teeth

and words and phrases commonly used with parents suggested by pediatric dental faculty and

residents. First the word list was read aloud (word recognition) and then the parents were

asked to give a verbal definition of each term (vocabulary knowledge). To determine oral health

comprehension (vocabulary comprehension), parents were read brief passages from oral health

education brochures and were asked to answer a question about the passage. OH-LIP showed

good to excellent internal reliability (Cronbach α = 0.93, 0.87 and 0.86 for word recognition,

vocabulary knowledge and comprehension scores, respectively). Intra-rater reliability was

established based on excellent Intraclass Correlation Coefficient (ICC) values (ICC=0.98, 0.94 and

0.95 for word recognition, vocabulary knowledge and comprehension scores, respectively). This

inventory allowed the authors to examine the correlation between word recognition ability of

the parents and their vocabulary knowledge and comprehension. Word recognition of the

dental terms was not associated with vocabulary knowledge (r=0.29, P<.06) or comprehension

(r=0.28, P>.06). On the other hand, vocabulary knowledge was strongly associated with

comprehension (r=0.80, P<.001).

Communicative and Critical Oral Health Literacy Instruments

No attempt to measure communicative and critical oral health literacy have been reported in

the literature.

26

1.14. Association between oral health literacy and oral health outcomes

The relationships between oral health literacy and some of the socio-demographic and

outcome variables are summarized in Table 3.

The association between age and oral health literacy was examined in 8 studies. Two of

these studies reported a significant association between age and oral health literacy.

The relationship between gender and oral health literacy was evaluated in 4 studies. All of

these studies reported no significant association between gender and oral health literacy.

The association between educational level and oral health literacy was examined in 8

studies. Six of these studies reported a significant positive association between educational

level and oral health literacy.

The association between oral health-related quality of life and oral health literacy was

evaluated in 4 studies. All of these studies reported a significant negative association

between the impact of oral health in the quality of life and oral health literacy.

The association between oral health knowledge and oral health literacy was evaluated in 6

studies. All of these studies reported a significant positive association between dental

knowledge and oral health literacy.

The association between self-reported perceived oral health status and oral health literacy

was evaluated in 8 studies. Five of the studies reported significantly higher oral health

literacy level for the participants with higher perceived oral health status.

The association between frequency of dental visits and oral health literacy was evaluated in

5 studies. Two of the studies reported significantly higher oral health literacy level for the

participants with more frequent dental attendance.

The association between oral health behaviors and oral health literacy was evaluated in 4

studies. Two of the studies reported better oral health behaviors for participants with

higher oral health literacy level.

The association between caregiver’s oral health literacy level and child oral health status

(on the basis of the severity of dental caries) was assessed in one of the studies. A

significant negative association between the caregiver’s literacy scores and the child’s

severity of dental caries was reported.

27

It has to be emphasized that some of these studies assessed the association at the bivariate

level only while others controlled for the relevant covariates, and vice versa. Details are

given in Table 3.

28

Table 1: Oral Health literacy instruments:

Study Aim Population Literacy

Measurement Recorded variables Method Results

Gong et al.66 To evaluate the

reliability and validity

of a new instrument to

measure functional

dental health literacy.

Parents of pediatric dental

patients (n=102) attending

Chapel Hill School of

Dentistry, University of

North Carolina.

Test of

Functional Health

Literacy in

Dentistry

(TOFHLiD),

Outcome variables

Self-perceived oral health

(for parents)

Parents’ perception of the

oral health of their children

OHQofL (OHIP-14)

Independent variables:

Parents’ dental services

use

Parents’ demographic

characteristics including

education, sex,, race,

ethnicity, and annual

family income

Construct Validity

(convergent and

discriminant) (correlation

of TOFHLiD with TOFHLA,

REALM and REALD-99

scores).

Predictive validity

(correlating TOFHLAiD to

dental outcomes

(parents’ self-perceived oral

health, parents’ perception

of the children’s oral health,

and OHIP-14 score)

Internal reliability

(Cronbach’s alpha)

The correlation coefficient

for TOFHLiD and REALD-99

scores was high (r = 0.82, P

< 0.05).

Coefficients between

TOFHLiD and TOFHLA (r =

0.52) and REALM (r =

0.53).

TOFHLAiD was associated

with parents’ OHIP-14

score in multivariate

analysis but not with

perceived oral health.

TOFHLAiD internal

reliability (Cronbach’s

alpha = 0.63)

Lee et al.68 To develop and pilot

test a word recognition

dental health literacy

English-speaking adults

(n=202) recruited from

outpatient medical clinics

Rapid Estimate of

Adult Literacy in

Dentistry (REALD-

Outcome variables


OHQofL (OHIP-14)

Convergent validity

(correlation of REALM,

TOFHLA and REALD-30

REALD-30 was positively

correlated with REALM

and TOFHLA (PCC = 0.86

29

instrument. at Chapel Hill School of


North Carolina.

30) Independent variables:

Dental services use

Participant demographic


education, sex,, race,


family income

scores).

Predictive validity

(correlating REALD-99 and

REALM individually to

dental outcomes

(self-perceived oral health,

and OHIP-14 score).


(Cronbach’s alpha).

and 0.64, respectively).

REALM was not related to

dental outcomes.

REALD-30 was associated





REALD-30 had good


alpha = 0.87).

Richman et

al.67

Development and

evaluation of a word

recognition dental

health literacy

instrument.

Parents of pediatric

patients (n=102) attending

Chapel Hill School of

Dentistry at University of

North Carolina.

Rapid Estimate of

Adult Literacy in

Dentistry (REALD-

99).

Outcome variables


(for parents)

Parents’ perception of the

oral health of their

children.

OHQofL (OHIP-14).


Parents’ dental services

use.

Parents’ demographic


Convergent validity

(correlation of REALM and

REALD-99 scores).

Predictive validity

(correlating REALD-99 and

REALM individually to

dental outcomes

(parents’ self-perceived oral

health, parents’ perception

of the children’s oral health,

and OHIP-14 score).


REALD-99 was positively

correlated with REALM

(PCC = 0.80).

REALM was not related to

dental outcomes.

REALD-99 was associated





REALD-99 had good


30

education, gender, race,


family income.


alpha = 0.86).

Sabbahi et

al.72

To develop and

validate an instrument

to measure the

functional oral health

literacy of adults.

A convenience sample

(n=100) of patients at

Faculty of Dentistry,

University of Toronto.

Oral Health

Literacy

Instrument

(OHLI).

Outcome Variables:

Oral health knowledge.

Frequency of dental visits.

Independent Variables

Sociodemographic

characteristics (age,

gender and education

level).

Concurrent validity was

tested by comparing OHLI

scores across categories of

education level and

frequency of dental visits.

Construct validity was

assessed by correlating

OHLI scores with TOFHLA

scores and with the oral

health knowledge scores.


(Cronbach’s alpha)

Test–retest reliability

(intra-class correlation

coefficient (ICC)).

Patients visiting a dentist

every 3–6 months had

significantly higher levels

of oral health literacy than

those visiting only when

they felt pain.

The association between

OHLI and education level

was not significant.

OHLI scores were

significantly correlated

with the scores on the

TOFHLA (q = 0.613) and

the test of oral health

knowledge (q = 0.573).

The Cronbach’s alpha

values were high (>0.7) for

OHLI and its components.

The ICC values indicated

good agreement between

31

the test and retest results

for OHLI and the oral

health knowledge test.

Atchison et

al.69

To evaluate a word

recognition health

literacy instrument

based on the Rapid

Estimate of Adult

Literacy in

Medicine (REALM) that

incorporates dental

and medical terms.

A sample of adult patients

(n=200) seeking treatment

for the first time at an oral

diagnosis clinic located in

a large urban medical

center in Los Angeles,

California.

Rapid Estimate of

Adult Literacy in

Medicine and

Dentistry

(REALM-D) (66

medical terms

and 18 dental

terms divided into

3 lists according

to difficulty).

Variables

Demographic

characteristics (sex, age,

race, Native language).

Self-reported health

Regular follow-up dental

visit (vs. no follow-up)

Need help reading hospital

forms

Confident filling out

medical forms

Insurance (yes/no)

Source of health

knowledge.

Criterion validity

(correlation of REALM-D

and the following

variables: need help

reading hospital forms,

confident filling out

medical forms and socio-

demographic variables).

All variables were collected

using a verbally-

administrated

questionnaire.



Test-retest reliability.

Participants who reported

always being confident

filling out medical forms

by themselves had

significantly higher

REALM-D scores. Similarly,

participants who reported

never needing someone to

help them read hospital

materials had significantly

higher REALM-D scores.

Race, education, and

English as a main language

were predictive of health

literacy at the bivariate

level

In a regression model, an

interaction between

education and English as a

main language was

32

significant.

REALM-D had good


alpha = 0.95).

Correlation between test

and retest scores was high

(r=0.95).

Stucky et al.

64

Revision of the 30 item

Rapid

Estimate of Adult

Literacy in Dentistry

(REALD-30), into a

more efficient and

easier-to use two-stage

scale (TS-REALD).

Female clients of the

Special Supplemental

Nutrition Program for

Women, Infants and

Children from

2007 to 2009 as part of

the Carolina Oral Health

Literacy Project (n=1280).

Rapid Estimate of

Adult Literacy in

Dentistry (REALD-

30) and Two-

stage REALD (TS-

REALD).

Outcome variables

OHQofL (OHIP-14).


Educational level, overall

health and dental health.

TS-REALD was constructed

based on the magnitude of

item information (based

on the item response

theory) at various levels of

dental health literacy.

The TS-REALD consists of

two stages. Based on the

participant’s score on the

five-item first-stage (i.e.,

routing test), one of three

potential stage-two tests is

administered: a four-item

Low Literacy test, a six-

item Average Literacy test,

or a three-item High

TS-REALD score was

positively correlated with

REALD-30 (PCC = 0.96).

TS-REALD score was

positively correlated with

NVS (PCC = 0.51).

The TS-REALD remained a

statistically significant

predictor for OHIP in a

multiple regression model

(b = 0.10, SE = 0.04, P <

0.05), after controlling for

the education level,

overall health and dental

health.

33

Literacy test.

Convergent validity

(correlation of TS-REALD

with REALD-30 and Newest

Vital Sign (NVS) scores).

Predictive validity (by

regressing the (OHIP-14), on

the TS-REALD, holding

constant educational level,

overall health, dental

health, and health literacy

(NVS score).



TS-REALD had good


alpha > 0.85).

Richman et

al.73

To develop a 3-part

Oral Health Literacy

Inventory for Parents

(OH-LIP),

To evaluate the

relationship of

parents’ oral health

literacy and parent-

A convenience sample of

parents of low-income

infants and pre-school

children in 2 Head Start

programs in western

Washington State (n=45).

Oral Health

Literacy

Inventory for

Parents (OH-LIP)

that assessed:

word

recognition;

vocabulary

Variables

Parent’s perception of the

child’s oral health status.

Current treatment needs.

The date of the child’s last

dental visit.

Parents’ socio-demographic

characteristics (race,

The OH-LIP was

administered as part of a

35-minute interview that

included assessments of

child oral health status and

family demographics.

Association between OH-

LIP components and

Parents’ ability to read

dental terms was not

associated with

vocabulary knowledge

(r=0.29, P<.06) or

comprehension (r=0.28,

P>.06) of the terms.

Vocabulary knowledge was

34

reported child oral

health status.

knowledge; and

comprehension

of 35 pediatric

oral health

terms.

ethnicity, income, gender,

marital status, educational

level, number of children,

and age of the study child)

parent’s educational level

and their perception of the

child’s oral health status

were measured.

The correlation between

components of OH-LIP was

measured.



Intra-rater reliability was

measured using the intra-

class correlation

coefficient (ICC) for audio

recordings.

strongly associated with

comprehension (r=0.80,

P<.001).

Parent-reported child oral

health status was not

associated with any of the

OH-LIP components

Associations between OH-

LIP 1 and 2 scores and

parental education were

not statistically significant.

In contrast, there was a

significant association

between OH-LIP 3 and

parental education and a

trend of increasing OH-LIP

scores with higher

education.

OH-LIP had excellent

internal reliability

(Cronbach’s alpha= 0.93,

0.87 and 0.86 for OH-LIP 1,

2 and 3, respectively).

35

The intra-class correlation

coefficients were 0.98,

0.94 and 0.95 for of OH-LIP

1, 2 and 3, respectively).

Wong et

al.71

Development and

validation of a word

recognition test, the

Hong Kong Rapid

Estimate of Adult

Literacy in Dentistry

(HKREALD-30)


parents of pediatric dental

patients attending the

Paediatric Dentistry Clinic

of the Prince Philip Dental

Hospital in Hong (n=200).

Rapid Estimate of

Adult Literacy in

Dentistry (REALD-

99).

Variables

Self-report reading habits

(the hours spent in

personal reading in the

past week)

Parents’ socio-

demographic

characteristics (age,

gender, education levels,

working status, family

incomes and pattern of

dental visits).

Concurrent validity was

tested by comparing the

HKREALD-30 scores with the

participants’ educational

level, pattern of dental

visits and reading habits.

Convergent validity

(correlation between

HKREALD-30 and the

translated TOFHLiD scores).



Test–retest reliability

(intra-class correlation

coefficient (ICC)).

A significant correlation (P

< 0.01) was found

between HKREALD-30 and

participants’ reading

habits (Spearman’s rho =

0.34). In contrast, the

associations between

HKREALD-30 and other

participants’

characteristics, such as

their educational level and

pattern of dental visits,

were not statistically

significant.

A significant correlation (P

< 0.01) was found

between HKREALD-30 and

TOFHLiD (Spearman’s rho

= 0.69).

36

(REALM) = Rapid Estimate of Adult Literacy in Medicine49

(TOFHLA) = Test of Functional Health Literacy of Adults9

(OHQofL) = Oral Health-related Quality of Life

(OHIP-14) = short-form Oral Health Impact Profile74

(PCC) = Pearson’s Correlation Coefficient

(DNS) = Dental Neglect Scale75

(GSES) = General Self-Efficacy Scale76

(ECOHIS) = Early Childhood Oral Health Impact Scale 77

HKREALD-30 was

associated with parents’

OHIP-14 score in

multivariate analysis but

not with perceived oral

health.

HKREALD-30 had good


alpha = 0.84).

The intra-class correlation

coefficient of HKREALD-30

was 0.78.

37

Table 2: Oral Health literacy studies (other than instruments):

Study Aim Population Literacy

Measurement Recorded variables Method Results

Jones et

al.78

This study examined

the association of

knowledge, dental care

visits and oral health

status with oral health

literacy in dental

patients.


adult patient in 2 private

practices in North Carolina

(n=101)

Rapid Estimate of

Adult Literacy in

Dentistry (REALD-

30)

Outcome Variables:

Overall dental knowledge

scored as incorrect if

answers to one or both of

two multiple-choice

questions regarding dental

caries prevention and

periodontal disease were

incorrect;

Whether the patient had

had a visit to the dentist in

the last 12 months; and

Self-assessment of oral

health status.


The value the patient

placed on oral health (as

gauged by treatment

preference for a bad tooth

Patients were asked to

answer a questionnaire to

collect the outcomes and

confounders.

The mean REALD-30 score

was 23.9 ([SD] = 1.29).

29% of the participants

had a low oral health

literacy level (scored

below 22 out of 30).

Participants who are not

married, who answered

dental knowledge

questions incorrectly, who

had not visited the dentist

in the past year, who

reported fair to poor oral

health, had low income, or

who had a high school

education or less, scored

low in the REALD-30

compared to their

reference groups.

38

being $155 for extraction

at one visit or $1,600 for

endodontic treatment and

crown completed in five

visits),

Patient type (new,

established),

Dental insurance status

(private, public, none),

Socioeconomic status

(annual income,

education, home

ownership) and

Demographic

characteristics (sex, age,

race, ethnicity, marital

status).

REALD-30 was significantly

associated with the 3 oral

health literacy-related

outcomes in the logistic

regression.

Age and marital status

were the only confounders

associated with oral health

literacy in the logistic

regression.

Parker and

Jamieson79

1) To determine the

relationship between

oral health literacy, as

assessed by

REALD-30, and oral



Indigenous adults living in

the Port Augusta region,

Australia (n=468)

Rapid Estimate of

Adult Literacy in

Dentistry (REALD-

30)

Outcome Variables:

Oral health literacy-related

outcomes (Oral health

knowledge, oral health

self-care and utilization of

dental services)


outcomes and self-

reported oral health

domains were measured

using a self-administrated

questionnaire.


was 15.0 (standard error =

0.36)

REALD-30 was significantly

associated with all

measured oral health

39

outcomes

2) To determine if oral


outcomes are risk

indicators for 7

domains of poor self-

reported

oral health

7 poor self-reported oral

health domains:

(1) having had one or more

teeth extracted

(2) rating oral health as ‘fair

or poor

(3) perceived need for fillings

or extractions;

(4) perceived gum disease;

(5) feeling uncomfortable

about appearance of teeth,

mouth or false teeth

(6) having avoided eating

some foods because of

problems with teeth, mouth

or false teeth and

(7) poor OHQofL


Demographic factors (age

and sex)

Socio-economic factors

(ownership of

Government-issued health

OHQofL was measured

using OHIP-14.

literacy-related outcomes


outcomes were risk

indicators for each of the

poor self-reported oral

health domains among this

population

40

care card)

Financial factors

(perceived difficulty paying

a $100 dental bill)

Miller et

al.80

To examine the

relationship of primary

caregivers’ literacy

with children’s oral

health outcomes

Children attending the

initial dental appointment

in the teaching clinics at

the Chapel Hill School of


North Carolina and their

caregivers (n=106).

Rapid Estimate of

Adult Literacy in

Dentistry (REALD-

30)

Outcome Variables:

Oral health knowledge

Oral health behaviours

Dental services use

Primary caregiver’s reports

of their child’s oral health

status

The clinical oral health

status of the child as

determined by a clinical

examination.


Dental insurance status

Socioeconomic status

(household annual income

and caregiver education)

and

Demographic

characteristics (Child

Child patient was assigned

by calibrated dental

examiners to 1 of 3

severity zones: (1) caries-

free and no treatment

needs; (2) low to

moderate treatment

needs, defined as visible

occlusal and posterior

interproximal carious

lesions; or (3) advanced

treatment needs, defined

as visible anterior carious

lesions.

Knowledge, behaviours,

dental services uses and

sociodemographics were

collected using a verbally

administrated

The bivariate analyses

showed no significant

relationships between

literacy and oral health

knowledge and

behaviours; however, both

reported perceived oral

health status and clinical

oral health status were

significantly associated

with literacy score.

The multivariate analysis

revealed a significant

relationship between

caregiver literacy scores

and clinical oral health

status as determined using

a standardized clinical

examination. Caregivers of

41

gender and race, and

caregiver marital status).

questionnaire. children with mild to

moderate treatment

needs were more likely to

have higher REALD-30

scores than those with

severe treatment needs.

Vann et al.65 To investigate the

association of female

caregivers’ oral health

literacy with their

knowledge,

behaviours, and the

reported oral health

status of their young

children.

Caregiver/child dyads

participants in Carolina

oral health literacy project

(n=1158).

Rapid Estimate of

Adult Literacy in

Dentistry (REALD-

30)

Outcome Variables:

Oral health knowledge,

Oral health behaviours,

Primary caregivers’ reports


status.


Caregivers’ demographic

information (age, race,

education, and number of

children)

Knowledge, behaviours,

and perceived oral health

status were collected using

a verbally administrated

questionnaire.

Low literacy scores (< 13)

were associated with

decreased knowledge and

poorer reported oral

health status

Lower caregiver literacy

was associated with

deleterious oral health

behaviours, including night

time bottle use and no

daily brushing/cleaning.

Lee et al.62 To examine the

associations of oral

health literacy (OHL)

with oral health status

(OHS) and dental

neglect (DN), and to




Women, Infants and

Children from


Rapid Estimate of

Adult Literacy in

Dentistry (REALD-

30)

Outcome Variables:

Self-reported oral health

status (OHS).

Dental Neglect.


Self-Efficacy

Oral health status, dental

use and demographics

were collected using a

questionnaire.

Dental Neglect was

measured using 6-item

Higher OHL was associated

with better OHS (for a 10-

unit REALD increase:

multivariate prevalence

ratio=1.29; 95%

confidence interval=1.08,

42

explore whether self-

efficacy mediated or

modified these

associations.



Dental use (the time since

the last dental visit)

Demographic information

(age, race and education)

scale (Dental Neglect Scale

(DNS)) describing the

participant dental

behaviors, with responses

ranging from ‘‘definitely

not’’ to ‘‘definitely yes’’ on

a 4- point Likert scale. (A

total cumulative score

ranging from 6 (least DN)

to 24 (most DN)).

Self-efficacy was measured

using General Self-Efficacy

Scale (GSES), a 10-item

scale to measure the

ability to cope with

general life. The scale’s

scores range from 10

(lowest self-efficacy) to 40

(highest self-efficacy).

1.54).

OHL was not correlated

with DN, but self-efficacy

showed a strong negative

correlation with DN.

Self-efficacy remained

significantly associated

with DN in a fully adjusted

model that included OHL.

Lee et al.63 To determine oral


levels and explore




Rapid Estimate of

Adult Literacy in

Dentistry (REALD-

Outcome Variables:

Oral health literacy


Demographics were

collected using an

interview.

OHL varied between racial

groups as follows:

- Whites– mean score =

43

potential racial

differences in a low-

income population.

Women, Infants and

Children from




30) Demographic information

(age, race, ethnicity,

marital status, and number

of children and education)

17.4 (SE = 0.2); African-

- American (AA) – mean

score = 15.3 [standard

error (SE) = 0.2]

- American Indian(AI) –

mean score = 13.7 (SE =

0.3).

Multiple linear regression

revealed that after

controlling for education,

county of residence, age,

and Hispanic ethnicity,

Whites had 2.0 points (95

percent CI = 1.4, 2.6)

higher adjusted REALD-30

score versus AA and AI.

Divaris et

al.61

1) To investigate the

association of oral


with Child- OHQofL

2) To explore the role

of OHL as a modifier in

the association

Caregiver/child dyads

participants in Carolina

oral health literacy project

(n=203).

Rapid Estimate of

Adult Literacy in

Dentistry (REALD-

30)

Outcome Variables:

Primary caregivers’ reports


status.

Oral health behaviours.


Caregivers’ demographic

Oral health behaviours,

and perceived oral health

status were collected using

a verbally administrated

questionnaire.

Low literacy scores was

defined to be (REALD30

Pronounced gradients

were noted in literacy

scores between racial and

age groups, as well as

levels of education.

There was no important

association between OHL

44

between child oral

health status and

Child- OHQofL

information (age, race, and

education).

score < 13)

Child- OHQofL was

measured using Early

Childhood Oral Health

Impact Scale (ECOHIS).

and Child- OHQofL;

A strong correlation was

found between child oral

health status and Child-

OHQofL. The association’s

magnitude and gradient

were less pronounced

among caregivers with low

literacy.

Lower caregiver literacy

and Child- OHQofL were

associated with

deleterious oral health

behaviours, including night

time bottle use, high

frequency of juice intake

and high consumption of

sweets.

45

Hom et al.81 To determine the

patterns of association

between oral health

literacy (OHL) and oral

health knowledge

among patients who

were pregnant for the

first time.

Low-income patients who

were pregnant for the first

time. Patients were

recruited from Special

Supplemental Nutrition

Program for Women,

Infants and Children as

part of Carolina Oral

(n=119).

Rapid Estimate of

Adult Literacy in

Dentistry (REALD-

30)

Outcome Variables:

Oral health Literacy,


Oral health knowledge.

Demographic information

(county of residence, race,

ethnicity, education level,

marital status and age)

Oral health knowledge was

assessed by using a six-

item questionnaire.

Participants were asked to

answer “agree,”

“disagree” or “don’t

know” to knowledge

related statements.


was 16.4 (standard

deviation= 5.0)

The percentage of correct

responses for each oral

health knowledge item

ranged from 45 to 98%.

A positive correlation

between OHL and oral

health knowledge was

detected (P < .01).

Higher OHL levels were

associated with correct

responses to two of the

knowledge items (P < .01).

A positive correlation

between OHL and

education level was

detected (P < .01).

No association between

OHL and age (range, 18.1-

39.3 years).

46

(REALM) = Rapid Estimate of Adult Literacy in Medicine49

(TOFHLA)= Test of Functional Health Literacy of Adults9

(OHQofL) = Oral Health-related Quality of Life

(OHIP-14) = short-form Oral Health Impact Profile74

(PCC) = Pearson’s Correlation Coefficient

(DNS) = Dental Neglect Scale75

(GSES) = General Self-Efficacy Scale82

(ECOHIS) = Early Childhood Oral Health Impact Scale 77

47

Table 3: Relationships between Oral Health Literacy and some of the Socio-demographic and

Oral Health Outcome Variables:

Variable Author OHL instrument

used Association with OHL

Age Jones et al.78 REALD-30 NS at bivariate level but significant at multivariate

level.

Atchison et al.69 REALM-D NS at bivariate and multivariate levels.

Vann et al.65 * REALD-30 Similar oral health literacy score for different age

groups (no statistical analysis).

Sabbahi et al.72 OHLI NS at bivariate and multivariate levels.

Wong et al.71 TOFHLiD** NS at multivariate level (no details were reported

about the bivariate analysis).

HKREALD-99 NS at multivariate level (no details were reported


Lee et al. 63* REALD-30 NS at multivariate level (no details were given


Divaris et al.61 * REALD-30 Significant at bivariate level (no multivariate

analysis was reported).

Hom et al. 81 REALD-30 NS at bivariate level (no multivariate analysis was

reported).

Gender Jones et al.78 REALD-30 NS at bivariate level (the gender was not included

in the multivariate analysis)

Atchison et al.69 REALM-D NS at bivariate and multivariate levels.


Wong et al.71 TOFHLiD** NS at multivariate level (no details were given




Education Jones et al.78 REALD-30 Significant (+ve) at bivariate, not multivariate level.

Atchison et al.69 REALM-D Significant (+ve) association at bivariate and

multivariate levels.


Wong et al.71 TOFHLiD** NS at multivariate level (no details were reported




Lee et al.62*** REALD-30 Significant (+ve) at bivariate level (no multivariate


48



Lee et al.63 * REALD-30 Significant (+ve) at multivariate level (no details

were reported about the bivariate analysis).

Divaris et al.61 * REALD-30 Significant (+ve) at bivariate level (no multivariate


Hom et al. 81 REALD-30 Significant (+ve) at bivariate level (no multivariate


Oral Health-

related Quality

of Life

Richman et al.67 REALD-99 Significant (-ve) with OHIP-14 at bivariate and


Lee et al.68 REALD-30 Significant (-ve) with OHIP-14 at multivariate level

(no details were reported about the bivariate

analysis).

Gong et al.66 TOFHLiD Significant (-ve) with OHIP-14 at bivariate and


Parker et al.79 REALD-30 Significant (-ve) with OHIP-14 at bivariate, not

multivariate level.

Dental

Knowledge

Parker et al.79 REALD-30 Significant (+ve) at bivariate, not multivariate level.

(knowledge was assessed using 2 questions about

frequency of brushing and effect of cordial on oral

health)

Jones et al.78 REALD-30 Significant (+ve) at bivariate and multivariate

levels.


dental caries prevention and periodontal disease)

Miller et al.80 REALD-30 Significant (+ve) at bivariate level with 5/11

questions (no multivariate analysis was reported).

(knowledge assessed using 11 questions about

children oral health)

Vann et al.65 REALD-30 Significant (+ve) at multivariate level (no details

were reported about the bivariate analysis).


children oral health)

Sabbahi et al.72 OHLI Significant (+ve) at bivariate and multivariate levels

(knowledge was assessed using knowledge test

consists of seven pictures depicting 17 labelled

items such as perioral and intra-oral structures,

oral diseases and conditions, dental fillings, a

dental prosthesis, and different oral hygiene aids.

49



To the left of each picture is a list of numbered

words. Participants were asked to match the

picture with the numbered item).

Hom et al. 81 REALD-30 Significant (+ve) at bivariate level (no multivariate

analysis was reported)

(knowledge was assessed using 6-item

questionnaire)

Perceived Oral

Health Status

Richman et al.67 REALD-99 Significant (+ve) at bivariate level, not multivariate

level.

Lee et al.68 REALD-30 NS at multivariate level (no details were reported


Gong et al.66 TOFHLiD NS at bivariate and multivariate levels.

Jones et al.78 REALD-30 Significant (+ve) at bivariate, not multivariate level.

Atchison et al.69 REALM-D NS at bivariate and multivariate levels

Vann et al.65 REALD-30 Significant (+ve) at multivariate level (no details

were reported about the bivariate analysis)

Lee et al.62*** REALD-30 Significant (+ve) at bivariate level (no multivariate


Richman et al.73 OH-LIP Significant (+ve) at multivariate level

Frequency of

Dental Visits

Jones et al.78 REALD-30 Significant (+ve) at bivariate, not multivariate level.

Atchison et al.69 REALM-D NS at bivariate and multivariate levels

Sabbahi et al.72 OHLI Significant (+ve) at bivariate and multivariate level.

Lee et al.62*** REALD-30 NS at bivariate level (no multivariate analysis was

reported).

Wong et al.71 TOFHLiD ** NS at multivariate level (no details were given




Oral Health

Behavior

Parker et al.79 REALD-30 Significant (+ve) at bivariate, not multivariate level.

(behavior was assessed using 2 questions about

owning a toothbrush and if the participant brush

his/her teeth yesterday).

Miller et al.80 REALD-30 NS at bivariate level (no multivariate analysis was

reported).


oral care for the child)

Divaris et al.61 REALD-30 Significant (+ve) at bivariate level (no multivariate

50





night time bottle use, high frequency of juice

intake and high consumption of sweets).

Lee et al.62*** REALD-30 NS at bivariate level (no multivariate analysis was

reported)

(behavior was assessed using the dental neglect

scale)

Dental Caries

and Treatment

Needs

Miller et al.80 REALD-30 Significant (-ve) relationship at bivariate and

multivariate levels between caregiver literacy

scores and the child clinical oral health status (on

basis of severity of dental caries) as determined

using a standardized clinical examination to

classify the treatment needs (as mild, moderate

and advance).

* Studies reported results from same cohort. OHL=Oral Health Literacy

** translated to Chinese

*** No significant value was provided by author (calculations were done using the provided

means and SD and one-way ANOVA)

REALD-30 = Rapid Estimate of Adult Literacy in Dentistry-30

REALD-99 = Rapid Estimate of Adult Literacy in Dentistry-99

OHLI = Oral Health Literacy Instrument

TOFHLiD = Test of Functional Health Literacy in Dentistry

REALM-D = Rapid Estimate of Adult Literacy in Medicine and Dentistry

OH-LIP = Oral Health Literacy Inventory for Parents

HKREALD-99 = Hong Kong Rapid Estimate of Adult Literacy in Dentistry

NS = Not significant

+ve = Positive Association

-ve = Negative Association

51

Objectives

52

Objectives:

The objectives of this study were:

1. To develop a test to assess critical and communicative oral health literacy and

assess its reliability and validity.

2. To confirm the validity of the OHLI by

i. evaluating the association between its scores and other health and oral

health literacy test scores (construct validity).

ii. assessing the association between oral health literacy, measured with the

OHLI, and different patient-centred and clinical outcomes (predictive

validity).

3. To examine the association between oral health literacy screening questions and

oral health literacy.

4. To examine the relationship between oral health literacy and dentist-patient

communication. The following objectives were studied:

a. examining the relationship between oral health literacy and quality of

dentist–patient communication.

b. exploring the pattern of communication between undergraduate dental

students and their patients at the Faculty of Dentistry Clinics.

c. determining barriers preventing patients from understanding oral health

information and performing oral hygiene measures.

53

Materials

&

Methods

54

Study Protocol

Participants and Patient Recruitment

As part of the education process, all patients attending the Faculty of Dentistry are

extensively examined by the undergraduate students in the Oral Diagnosis and Undergraduate

clinics in order to evaluate patient oral health status and provide an appropriate treatment plan.

This extensive oral examination process includes full dental and periodontal charting. The new

patient screening and examination protocol at the Faculty of Dentistry is highlighted in Figure 4.

The participants in this study were recruited from the pool of new patients attending the

Faculty of Dentistry Clinics at the University of Toronto (convenience sample). Pre-established

exclusion criteria were used in this study, which excluded those persons younger than 19 years

old, those with hearing or vision impairment, those with any physical disabilities, uncooperative

patients and those who could not speak, read and understand English well (because all the used

instruments and tests are in English). First, the participants were asked, during the recruitment

visit, if they can read, speak and understand English (well, little, or none). Only those who

reported that they could read, speak and understand English well were chosen to participate in

the study.

Ethics approval

The research protocol was approved by University of Toronto Research Ethics Committee.

(Appendix I)

55

Figure 4: New patient screening and examination protocol at the Faculty of Dentistry

Initial Screening

Initial screening is done by one of the clinic instructors to determine the suitability of the

patient for the educational needs of the Faculty.

The required diagnostic radiographs are requested for suitable patients.

Location: Oral Diagnosis and Oral Radiology Clinics.

Oral Diagnosis Visit

The oral diagnosis visit is carried out by one of the undergraduate students (3rd or 4th year

students).

The medical history of the patient is collected.

Required medical referrals or letters are sent to the patient's physician.

Full dental charting is completed.

Location: Oral Diagnosis Clinic

Diagnosis and Treatment planning

Diagnosis and treatment planning is done by one of the undergraduate students (3rd or 4th year

students).

Periodontal charting is completed as part of the extensive examination procedure in order to

establish the proper diagnosis for the patient condition and develop the appropriate treatment

plan.

Location: Undergraduate Clinic.

Patient is assigned to one of the undergraduate students.

56

Procedure:

This study consisted of 2 visits only. Participants received $18 (40%-50% of the oral

diagnosis visit fees ($42)) as compensation for participating in the study. The participant was

given the option to receive this compensation in cash or as a credit toward his/her dental

treatment at the Faculty of Dentistry.

The duration of the first visit was about 47 minutes, while the second visit took about 2

minutes. More details about the expected duration to complete the tests and questionnaires

related to this study are provided in Table 4.

Participants were first approached in the waiting area in front of the Dental Screening Clinics

at the Faculty of Dentistry and were introduced to the project and asked if they were willing to

participate in the study.

All participants who agreed to join the study signed a consent form (Appendix II) and were

handed a package that consisted of the following self-administrated questionnaires:

A questionnaire (Appendix III) about the following independent variables:

o Demographic (age, gender and native language)

o Socio-economic (education level and annual income)

o Dental usage (frequency and nature of dental visits)

o Oral health behaviour (having a toothbrush, frequency of brushing and

frequency of dental flossing)

o Dental insurance

o Self-perceived oral health status

Health literacy screening questions, which were developed by Chew and colleagues83

(Appendix IV). More details about the health literacy screening questions are provided

in a following section (part 3).

Interpersonal Processes of Care in Diverse Populations Questionnaire (IPC) (Appendix V).

More details about IPC are provided in a following section (part 4).

Oral Health Impact Profile (OHIP-14) (Appendix VI) 74.

Previously developed dental knowledge test (Appendix VII) 72.

Comprehension part of the Oral Health Literacy Instrument (OHLI) (Appendix VIII)72.

57

The length of time required to finish the above questionnaire and tests by the patient was

about 36 minutes. The participants completed those forms during their Radiology appointment

(while the students were waiting for the x-rays to be processed or discussing the case with the

Oral Radiology instructors).

After the completion of the appointment but before leaving the faculty, the participants

were asked to stay for around 13-15 more minutes to complete the following tests and

questionnaires:

Numeracy part of the Oral Health Literacy Instrument (OHLI) (Appendix VIII)72.

Rapid Estimate of Adult Literacy in Medicine (REALM) (Appendix IX)49.

Rapid Estimate of Adult Literacy in Dentistry (REALD-30) (Appendix X)68.

Critical and Communicative Oral Health Literacy Instrument (CCOHLI) (Appendix XI). (The

time required to complete CCOHLI were recorded)

Details of the OHLI, REALD-30, REALM, knowledge test and OHIP-14 can be found in Table 5.

All interviews were conducted for each participant individually in a quiet room. Those

questionnaires and tests were administered by the primary investigator who recorded the

responses of the participants.

Two to three weeks after the first visit, during their next scheduled appointment (Oral

Diagnosis appointment), the participants were asked to fill a questionnaire about the pattern of

communication between the undergraduate dental students and themselves and the barriers

they encountered in understanding the provided dental information and in performing oral

hygiene measures (Appendix XII). The time needed to complete this questionnaire was

approximately 2 minutes. In addition, at least 20% of the participants were randomly selected

and retested using the CCOHLI, which also took about another 2 minutes.

Data Extraction from the Dental Chart

The patients’ charts were accessed to calculate the number of decayed, missing and filled

teeth (DMFT) index, for all teeth excluding the 3rd molars, and to assess the periodontal pocket

depths, as recorded by the undergraduate students in the oral diagnosis and treatment planning

58

sessions. The periodontal pocket depths were recorded in mm at 6 sites (mesiofacial, mid-facial,

distofacial, distolingual, mid-lingual and mesiolingual) around each tooth except the 3rd molars.

Sample Size Calculation

The sample size was calculated to detect a medium effect size (f2=0.15, R2=0.13) for 17

independent predictors on the oral health literacy score (outcome), at α=0.05 and β=0.2. The

calculation was conducted using IBM SPSS Sample Power (Version 3.0, SPSS Inc., IBM, Somers,

New York, USA), which yielded a sample size of approximately 147 participants. Around 20% of

the yielded sample size was added to accommodate for any loss of subjects.

59

*Time was estimated based on the data reported in the literature (when available) or arbitrary

estimated.

Table 4: The duration for the tests and questionnaires that were used in the project *

Item Typical duration in

minutes

Questionnaire (Appendix III) 5

Health literacy screening Questions (Appendix IV) 1

IPC (Appendix V) 5

OHIP-14 (Appendix VI) 5

Knowledge test (Appendix VII) 3

OHLI (Appendix VIII) 20

REALM (Appendix IX) 3

REALD-30 (Appendix X) 3

CCOHLI (Appendix XI) 2

Questionnaire about student-patient communication and barriers

encountered by the patient (Appendix XII) 2

60

Table 5: Details of oral health/health literacy, knowledge and quality of life tests:

Test Description Scoring and Cut-off Points Administration time

OHLI72 The OHLI, a functional oral health literacy

instrument, consists of two sections: reading

comprehension and numeracy.

-The reading comprehension section is a 38-item

test with words omitted from two passages, one

on dental caries and the other on periodontal

disease. The dental caries passage contains 13

sentences with 264 words, while the periodontal

disease passage consists of 14 sentences with

228 words. Using a modified Cloze procedure

4;9;34, the test was developed by selectively

omitting certain words from the two passages.

Four possible choices are offered, one of which is

correct; the remaining choices are either similar

sounding words or grammatically or contextually

incorrect terms. The readability levels of the

passages, according to the Flesch-Kincaid Grade

Level scale, are 7.6 and 8.1 (grade 8 level),

Scoring: one point was assigned for each item if

answered correctly or zero (0) if answered

incorrectly. Later, the raw scores of the reading

comprehension and numeracy sections were

multiplied by (50/38) and (50/19), respectively,

to create a weighted score from 0 to 50. The

OHLI score, which ranges from 0 to 100, was

equal to the sum of both sections.

Cut-off point:

Inadequate (0-64),

Marginal (65-79),

Adequate (80-100).

20 minutes

(15 minutes for

comprehension part

+ 5 minutes for the

numeracy part)

61

respectively, and on the Flesch Reading Ease

scale are 73.6 and 65.1 (understandable by 13-

to15-year old students), respectively.

- The numeracy section consists of 19 items to

test the participant’s ability to comprehend

directions for taking some of the common

prescriptions associated with dental treatment,

post-extraction instructions, and clinical

appointments.

In the reading comprehension section

participants were handed the reading

comprehension passages and asked to write their

answers in a test booklet. While in the numeracy

section, participants were provided with labeled

medication bottles, an appointment card, and an

instruction pamphlet. They were then asked

questions by the investigator who recorded the

answers on the answer sheet.

REALD-3068 The REALD-30, a word recognition test, consists

of 30 dental health-related words arranged

according to degree of difficulty.

Scoring: one point was assigned for each word

pronounced correctly and summed to get the

overall score. The total score has a possible

3 minutes

62

The REALD-30 test was designed to be read aloud

by subjects to the interviewer.

range of 0 (lowest literacy) to 30 (highest

literacy).

There is no cut-off point to differentiate

between oral health literacy levels.

Cut-off points for literacy level78:

Low: ≤ 21

Marginal: 22 - 25

High: ≥ 26

REALM49 The REALM, a word recognition test, consists of

66 health-related words arranged according to

degree of difficulty.

The REALM test was designed to be read aloud by

subjects to interviewer.

Scoring: one point will be assigned for each word

pronounced correctly and summed to get the

overall score. The total score has a possible

range of 0 (lowest literacy) to 66 (highest

literacy).

Cut-off points for literacy level:

Low: 0 - 44

Marginal: 45 - 60

Adequate: 61-66

3 minutes

Knowledge test72 Developed specifically to evaluate the

participant’s general dental knowledge.

This knowledge test consists of seven pictures

Scoring: each item was scored with one (1) if

answered correctly or zero (0) if answered

incorrectly.

3 minutes

63

showing some perioral and intraoral structures,

oral conditions and diseases, dental fillings,

dental prosthesis, and oral hygiene aids. Certain

parts (17 items) of these pictures are labeled. To

the left of each picture is a list of numbered

words. Each participant was asked to choose the

word from the word list that describes the

labeled part.

The raw scores were multiplied by (100/17)

5.88, to create a weighted score that ranged

from 0 (lowest knowledge) to 100 (highest

knowledge).

OHIP-1474 The OHIP-14 consists of 14 questions, regarding

the extent to which oral health problems affect the

subjects’ overall quality of life, addressing seven

dimensions based on the theoretical and

conceptual model of oral health formulated by

Locker84: functional limitation, physical pain,

psychological discomfort, physical disability,

psychological disability, social disability, and

handicap.

Scoring: Each of the seven subscales has two

questions graded on a five-point Likert scale for

which patients choose an answer using the

following codes: 0—never;1—hardly ever; 2—

occasionally; 3—fairly often; 4—very often.

The OHIP-14 data was summarized using 3

summary variables as suggested by Slade and

colleagues85:

Prevalence: the percentage of respondents

reporting one or more items ‘fairly often’ or

‘very often’.

Extent: the number of items reported

‘fairly often’ or ‘very often’.

5 minutes

64

Severity: the sum of ordinal responses for

the 14 items. Hence, severity takes into

account impacts experienced occasionally

or hardly ever, and can range from 0

(lowest oral health problems and higher

quality of life) to 56 (highest oral health

problems and lower quality of life).

65

PROJECT PARTS

This project consisted of 4 parts.

Part 1: Development and Validation of the Critical and Communicative Oral Health

Literacy Instrument (CCOHLI)

Part 2: Further Validation of the Oral Health Literacy Instrument (OHLI)

Aim and Rationale

Previous research on oral health literacy has focused on functional and basic health literacy.

Greater value may be found in assessing oral health literacy beyond the functional level,

including the abilities to extract, communicate, critically analyze, and use oral health

information. A thorough literature review revealed that no validated instrument has been

developed to assess communicative and critical oral health literacy.

The aim of part 1 was to develop an instrument to assess communicative and critical oral

health literacy. This proposed instrument, in addition to existing functional oral health literacy

instruments (reading comprehension and word recognition instruments), will allow the

assessment of all levels of oral health literacy (functional, communicative and critical) and will

help in identifying barriers that might contribute to participant oral health literacy inadequacy.

The aim of part 2 was to confirm the validity of the previously developed OHLI by

i. evaluating the association between its scores and other health and oral health

literacy test scores (construct validity).

ii. assessing the association between oral health literacy, measured with OHLI, and

different patient-centred and clinical outcomes (predictive validity).

The results of part 2 will help in improving our understanding of oral health literacy, its

determinants and its association with different oral health outcomes.

66

Development of CCOHLI

The CCOHLI was created based on a previous scale that was developed to assess

communicative and critical health literacy among diabetic patients54. Communicative oral health

literacy was evaluated with five items assessing the extent to which patients had extracted and

communicated oral health-related information. Critical oral health literacy was evaluated by

four items assessing the extent to which patients had critically analyzed the information and

used it to make decisions. Each item was rated on a 4-point scale, ranging from 1, (never) to 4,

(often), with higher scores indicating higher oral health literacy. The scores for the items were

summed and divided by the number of items in the scale to give the test score (theoretical

ranges between 1 and 4).

Participants were divided into 2 communicative and critical oral health literacy levels based

on their CCOHLI overall scores: inadequate (<3) and adequate (≥3).

Validation of the instruments (CCOHLI and OHLI)

Validity Testing

Validity, defined as the degree to which a scale measures what it purports to measure86, was

assessed for CCOHLI and OHLI as follows:

1. Face validity, which indicates that the instrument appears to measure what it is

designed to measure, was established by three experts in the fields of community

dentistry, preventive dentistry and public health. The newly developed CCOHLI was

given to the experts, who were asked to assess the test for face validity. The face

validity of the OHLI was not evaluated in this study since it has been previously

established87.

2. Construct validity, which is comprised of convergent and discriminant validity was

assessed as follows:

Convergent validity was assessed by correlating the CCOHLI score with

instruments that measure similar construct (dental health literacy), REALD-

30 and OHLI scores, which have already established reliability and validity.

67

The convergent validity of OHLI was confirmed by correlating its score with

REALD-3087.

Discriminant validity was assessed by correlating the CCOHLI and OHLI

scores with an instrument that measures a different construct (Medical

health literacy), REALM scores which has established reliability and

validity87.

3. Predictive validity, which measures the association of the instrument score with an

external criterion of the phenomenon under study taken at the same point in time,

was assessed by comparing the result of the CCOHLI and OHLI with the patient’s

dental knowledge, educational level, dental usage, oral health behaviour, self-

perceived oral health status, patient’s oral health-related quality of life, DMFT score

and periodontal condition. The following hypotheses were tested: participants with

low oral health literacy will have lower dental knowledge, educational level, dental

usage, perceived oral health status as well as inadequate oral health behaviour, and

higher DMFT, and deeper periodontal pockets when compared to participants with

high oral health literacy.

Reliability Testing

Reliability, defined as the degree of stability exhibited when the measurement is repeated

under identical conditions86, was assessed for CCOHLI using the test-retest method and by

calculating the intra-class correlation coefficient (ICC), which was computed for the CCOHLI for

the patients who completed the questionnaire twice, at a two-week interval. The internal

consistency reliability of the CCOHLI’s items for the overall sample was calculated using

Cronbach’s alpha formula, which was used to assess the consistency of results across items

within a test. The reliability of the OHLI was not evaluated in this study since it has been

previously established72.

68

Data Analysis

Descriptive statistics (frequencies, proportions, percentages, means and accompanying

standard deviations or 95% confidence intervals where appropriate) were used to summarize

the recorded variables. Descriptions of variables that were recorded in these 2 parts can be

found in Table 6. For the purpose of bivariate and multivariate analyses, categorical variables

with more than 2 levels were dichotomized.

The internal consistency of the items in the CCOHLI was determined by using Cronbach’s

alpha coefficient. The intraclass correlation coefficient (ICC) was used to assess the reliability of

the test-retest results.

Spearman’s correlation was used to measure the following:

association of the total scores of OHLI with REALD-30 scores, REALM scores, the

weighted scores of the knowledge test and different variables used to summarize

the OHIP-14 data (extent and severity of impacts of oral disorders).

association of the CCOHLI scores with OHLI scores, REALD-30 scores, REALM scores,

the weighted scores of the knowledge test and different variables used to

summarize the OHIP-14 data (extent and severity of impacts of oral disorders).

correlation between the total scores of OHLI, CCOHLI and REALD-30 with DMFT

scores

The Mann-Whitney U test was used to:

compare the test scores (OHLI overall score, CCOHLI score, REALD-30 score, REALM

score and the knowledge test weighted score) for the subgroups divided by gender,

native language, time being in Canada, education level, last year household income,

last dental visit, nature of last dental visit, attendance of regular dental check-up

visits, frequency of teeth brushing/day, frequency of interdental flossing and self-

perceived oral health status.

measure the association between the knowledge test weighted score and oral

health literacy levels measured using the following instruments: CCOHLI, OHLI and

REALD-30.

69

measure the association between health literacy levels (adequate and marginal or

inadequate), measured by REALM, and the knowledge test weighted score.

compare the extent and severity of impacts of oral disorders, measured with OHIP-

14, among the subgroups divided by the levels of oral health literacy measured

using the following instruments: CCOHLI, OHLI and REALD-30.

compare the extent and severity of impacts of oral disorders, measured with OHIP-

14, among the subgroups divided by the levels of health literacy measured using

REALM.

compare the DMFT scores and its components among the subgroups divided by the

levels of oral health literacy measured using the following instruments: CCOHLI,

OHLI and REALD-30.

compare the DMFT scores and its components among the subgroups divided by the

levels of health literacy measured using REALM

The Kruskal-Wallis test was used to compare the test scores (OHLI overall score, CCOHLI

score, REALD-30 score, REALM score and the knowledge test weighted score) for the subgroups

divided by age.

The Chi-square test (or the Fisher’s exact test) was used to:

evaluate the association of the levels of oral health literacy (categorised), measured

using REALD-30, OHLI and CCOHLI, with the following variables: gender, native

language, socio-economic data, dental usage, oral health behaviour and self-

perceived oral health status.

evaluate the association between the prevalence of oral impacts fairly often/very

often (as measured by OHIP-14) and REALD-30 (categorical), OHLI (categorical) and

CCOHLI (categorical).

evaluate the association between the prevalence of the of the periodontal pockets

depths (participants with all pockets ≤3mm or participants with at least one pocket

>3mm) and oral health literacy level (categorised), measured using REALD-30, OHLI

and CCOHLI.

70

Logistic regression (using forced-entry technique) was used to evaluate the association

between the oral health literacy level measured using OHLI, CCOHLI and REALD-30, as the

dependent variable, and the following independent variables: patient’s demographic and socio-

economic data, dental usage, oral health behaviour variables, self-perceived oral health status,

dental knowledge score, prevalence of untreated caries, number of missing teeth (MT), ratio of

filled teeth to the DMFT score (FT/DMFT) and OHIP-14 prevalence score. The variance inflation

factor (VIF) and tolerance were used for the multicollinearity diagnosis. VIF and tolerance values

more than 10 or tolerance values less than 0.4 were used as an indicator for the presence of

multicollinearity.

The data were analyzed using the SPSS software for Windows (version 20, SPSS Inc., IBM,

Somers, New York, USA). All statistical tests were two-tailed and performed at an alpha level of

0.05. Normality of the data distribution was evaluated before the statistical analysis and non-

parametric tests were used due to departure from normality for most of the continuous

variables.

71

Table 6: Variables used in the statistical analysis for part 1 and their coding

Variable Type Variable levels/Range

Age Continuous -

Age groups Categorical (Ordinal)

18-24 years old=0

25-44 years old=1

45-64 years old=2

+65 years old=3

Gender Categorical

(Nominal)

Female=0

Male=1

Native language Categorical

(Nominal)

English=0

Other=1

Time being in Canada Categorical

(Nominal)

More than 10 years =0

5-10 years =1

Less than 5 years =2

Place where they grew up Categorical

(Nominal) -

Education level Categorical (Ordinal)

Postgraduate education =0

College degree =1

Some college =2

High school or less =3

Household annual income

last year Categorical (Ordinal)

More than $ 80,000 = 0

$ 60,000- $ 79,999 = 1

$ 40,000- $ 59,999 = 2

$ 20,000- $ 39,999 = 3

Less than $ 20,000 = 4

Reason for your choice of

being a patient at the Faculty

Categorical

(Nominal)

Referred by dentist : (Yes = 0, No = 1, for each of the

following)

To treat dental emergency

To treat my dental problems

For Check-up or future treatment

Usual source of dental

information

Categorical

(Nominal)

(Yes = 0, No = 1, for each of the following)

Never looked into

My dentist

Other health professional

Media

Internet

Others

Advice in case of dental

emergency

Categorical

(Nominal)

(Yes = 0, No = 1, for each of the following)

Family

Friends

Continued on the next page

72

Family physician

Dental health professional

I figure it out myself

Others

Last dental visit Categorical (Ordinal)

Had visited the dentist:

In the past 12 months = 0

Greater than 12 months = 1

Never = 2

Nature of last dental visit Categorical

(Nominal)

Check-up = 0

Emergency = 1

To receive scheduled dental treatment = 2

For consultation = 3

Attending regular check-up

visit

Categorical

(Nominal)

Yes = 0

No = 1

Ownership of tooth brush Categorical

(Nominal)

Yes = 0

No = 1

Frequency of teeth

brushing/day Categorical (Ordinal)

More than twice = 0

Twice = 1

Once = 2

None = 3

Dental flossing Categorical

(Nominal)

Yes = 0

Sometimes= 1

No = 2

Methods of paying dental

costs

Categorical

(Nominal)

Insurance from work = 0

Governmental assistant = 1

By me “no insurance” = 2

Other = 3


status Categorical (Ordinal)

Excellent = 0

Very good = 1

Good = 2

Fair = 3

Poor = 4

OHLI reading weighted score Continuous 0-50

OHLI numeracy weighted

score Continuous 0-50

OHLI overall score Continuous 0-100

OHLI level

(Oral health literacy level) Categorical (Ordinal)

Adequate = 0

Marginal = 1

Inadequate = 2

CCOHLI score Continuous 0-4


73

CCOHLI level


Adequate= 0

Inadequate = 1

REALD-30 score Continuous 0-30

REALD-30 level


High = 0

Marginal = 1

Low = 2

REALM score Continuous 0-66

REALM level

(Health literacy level)

Low: 0 - 44

Marginal: 45 - 60

Adequate: 61-66

Knowledge test weighted

score Continuous 0-100

OHIP-14 prevalence score Continuous 0-100

OHIP-14 extent score Continuous 0-14

OHIP-14 severity score Continuous 0-56

DT (Decayed Teeth) Continuous 0-28

MT (Missing Teeth) Continuous 0-28

FT (Filled Teeth) Continuous 0-28

DMFT Continuous 0-28

DT*100/DMFT Continuous 0-100

MT*100/DMFT Continuous 0-100

FT*100/DMFT Continuous 0-100

Prevalence of periodontal

pockets by highest score Categorical (Ordinal)

Participants with all sites ≤3mm =0

Participants with at least one site( =4 mm) =1

Participants with at least one site( =5mm) =2

Participants with at least one site( =6mm) =3

Participants with at least one site( >6mm) =4

74

Part 3: Validation of Screening Questions for Limited Oral Health Literacy

Aim and Rationale

The ability to identify patients with potential oral health literacy problems is important in

order to overcome the adverse effects of limited oral health literacy. Despite the availability of

valid oral health literacy instruments, these instruments are time-consuming and not practical in

busy clinical settings. A set of brief and easy-to-use screening questions to identify patients with

inadequate oral health literacy will be a useful tool in busy dental practices.

The aim of this part was to evaluate the performance of 4 single-item screening questions

for identifying patients with limited oral health literacy compared to 3 oral health literacy tests,

OHLI, REALD-30 and CCOHLI. These screening questions provided a rapid and inexpensive way to

identify patients with limited oral health literacy that would increase the feasibility of assessing

a patient’s oral health literacy in a busy clinical setting or of conducting large-scale studies.

Method

The study used the health literacy screening questions developed by Chew and colleagues83.

The wording of the four questions of this instrument was slightly revised to make them more

relevant to the dental field. The responses to these screening questions were scored on a five-

point Likert scale ranging from “always=1” to “never=5”, with higher scores reflecting lower oral

health literacy for question 2 “confident in filling forms” and 3 “confident in following

instructions” and reflecting higher oral health literacy scores for question 1 “reading problems”

and 4 “help in reading hospital materials”.

The sensitivity, specificity, and positive and negative likelihood ratio (LR) with 95%

confidence intervals (CI) was calculated in comparison to the 3 oral health literacy tests studied

(REALD-30, OHLI, CCOHLI)88. Sensitivity and specificity data were used to produce the Receiver

Operating Characteristic (ROC) curves, which plot the sensitivity versus 1-specificity. The ROC

curves allow for the review of the trade-offs involved between improving either a question’s

sensitivity or its specificity. The areas under the ROC curve (AUROC) and their 95% confidence

intervals (CI) were used to compare the overall performance of the screening questions. An ideal

question is one that achieves an area of 1, and an area under the ROC of 0.5 indicates a

75

screening test that provides no useful information. In addition, the performances of various

combinations of questions were compared to the question with the highest AUROC score to

determine whether combining questions could improve the screening performance. To

determine the scores of different 2-item, 3-item and 4-item combinations, we have changed the

coding for questions one and four to be never=5 and always=1. Then, the questions scores were

summed to get a 10-, 15- or 25-point scales for the 2-item, 3-item and 4-item combinations,

respectively. The AUROC was calculated for the different combinations and compared to the

highest AUROC for single questions. The data were analyzed using the SPSS software for

Windows (version 20, SPSS Inc., IBM, Somers, New York, USA) and MedCalc 12.3.0 statistical

software (MedCalc Software bvba, Mariakerke, Belgium).

76

Part 4: Oral Health Literacy and Dentist-Patient Communication

Aim and Rationale

In the field of oral health literacy, most of the previous studies focused on patient ability to

read and comprehend written dental information and instructions. However, no attention was

directed to the relationship between oral health literacy and dentist-patient communication.

The aim of this part was to examine the association between oral health literacy and dentist-

patient communication. Understanding this relationship may provide important insights to the

dental community about interaction and communication with poor oral health literacy patients.

The objectives of this section were to:

1. assess the association between oral health literacy and quality of previous dentist-

patient communication, as perceived by the patient. The communication sub-scales of

the Interpersonal Processes of Care Questionnaire (IPC)89 were used to evaluate the

effect of previous dentist-patient communication experience on the patient oral health

literacy level. The following hypothesis was evaluated: “patients who had inadequate

communication experience with their dentists are expected to have limited oral health

literacy”. This hypothesis was tested by evaluating the association between the IPC

score and the oral health literacy level measured by different oral health literacy

instruments.

2. explore the pattern of communication between the undergraduate dental students

and their patients at the Faculty of Dentistry Clinics and determine the barriers

preventing patients from understanding the oral health information and performing

oral hygiene measures using a self-administrated questionnaire that was developed for

this purpose (Appendix XII).

77

Method

The quality of dentist-patient communication, as perceived by the patient, was measured

using the communication sub-scales of the Interpersonal Processes of Care in Diverse

Populations Questionnaire (IPC)89 which is self-administered. The IPC is a validated, self-report

questionnaire with high internal consistency reliability. The IPC, in its entirety, is a 40-item

questionnaire that asks patients to report their experience with their doctor in the prior 6

months across two domains: communication and interpersonal style. Because the aim of this

part was to assess the relationship between oral health literacy and patient-dentist

communication, we focused on the communication items, which are grouped into the seven

sub-scales of (1) general clarity, (2) elicitation of and responsiveness to patient problems,

concerns and expectations, (3) explanations of condition, progress, and prognosis, (4)

explanations of processes of care, (5) explanations of self-care, (6) empowerment, and (7)

decision-making. Each sub-scale is comprised of 2 to 7 items, and responses are given on a 5-

point Likert scale ranging from “always=1” to “never=5” with lower scores indicating better

communication, except for questions in the sub-scale of general clarity where higher scores

indicate better communication. Seventeen items were selected from the original measures and

the wording was slightly revised to make them more relevant to the dental field. For each

patient, a score was generated for each sub-scale by adding up individual item scores within the

sub-scale and dividing the total score by the number of items in the sub-scale (theoretical score

range between 1 and 5). After rounding the mean sub-scale scores to the nearest integer, mean

sub-scale scores of 4–5 on the Likert scale for positive attributes, corresponding to never/rarely,

were categorized as poor IPC, while mean sub-scale scores of 1–3 on the Likert scale,

corresponding to always/often/sometimes, were categorized as good IPC. On the other hand,

mean sub-scale scores of 1–3 on the Likert scale for negative attributes, corresponding to

always/often/sometimes, were categorized as poor IPC, while mean sub-scale scores of 4–5 on

the Likert scale, corresponding to never/rarely, were categorized as good IPC.

The pattern of communication between the undergraduate dental students and their

patients and the barriers encountered by the patients in understanding the provided dental

information and in performing oral hygiene measures were assessed using a self-administered

questionnaire (Appendix XII).

78

Data Analysis

Descriptive statistics (proportions, means and accompanying standard deviations or 95%

confidence intervals where appropriate) were used to summarize the recorded variables.

Descriptions of variables that were recorded in this part of the study can be found in Table 7

Spearman correlation was used to measure the correlation between the OHLI, CCOHLI and

REALD-30 and the dental knowledge test weighted scores with each of the IPC sub-scale scores.

The Mann-Whitney U test was used to:

compare the IPC score of each sub-scale for the subgroups divided by gender,

language, time being in Canada, education level, household income, time and

nature of last dental visit, attendance of regular dental check-up visits, tooth

brushing and flossing frequency and self-perceived oral health status.

assess the association between IPC sub-scales rating (poor and good) and the total

scores of OHLI, REALD-30 and CCOHLI.

The Kruskal-Wallis test was used to assess the differences in the IPC score of each sub-scale

for the subgroups divided by age.

The Chi-square test or the Fisher’s exact test were used to:

evaluate the association between the IPC rating (poor and good) with the following

variables: levels of oral health literacy (measured using REALD-30, OHLI and

CCOHLI), gender, socio-economic data, dental usage, oral health behaviour and self-

perceived oral health status

compare the responses to questions in the barrier questionnaire (Appendix XII)

between the third-year students (who just started their oral diagnosis clinic) and

fourth-year students.

Logistic regression (using forced-entry technique) was used to evaluate the association

between IPC score of each sub-scale, as the dependent variable, and the following independent

variables: total scores of OHLI, CCOHLI and REALD-30, patient’s demographic and socio-

79

economic data, dental care use, oral health behaviour variables, and dental knowledge score.

The variance inflation factor (VIF) and tolerance were used for the multicollinearity diagnosis.

VIF and tolerance values more than 10 or tolerance values less than 0.4 were used as an

indicator for the presence of multicollinearity.

The data were analyzed using the SPSS software for Windows (version 20, SPSS Inc., IBM,

Somers, New York, USA). All statistical tests were two-tailed and performed at an alpha level of

0.05.

80

Table 7: Variables that were used in the statistical analysis for part 4 and their coding

Variable Type Variable levels/Range

Age Continuous -

Age groups Categorical

(Ordinal)

18-24 years old=0

25-44 years old=1

45-64 years old=2

+65 years old=3

Gender Categorical

(Nominal)

Female=0

Male=1

Time being in Canada Categorical

(Ordinal)

More than 10 years =0

Less than 10 years =1

Education level Categorical

(Ordinal)

College degree or more=0

Less than college =1

Household annual income last year Categorical

(Ordinal)

$ 40,000 or more = 0

Less than $ 40,000 = 1

Last dental visit Categorical

(Ordinal)

Had visited the dentist:

In the past 12 months = 0

Greater than 12 months = 1

Nature of last dental visit Categorical

(Nominal)

Others = 0

Emergency = 1

Attending regular check-up visit Categorical

(Nominal)

Yes = 0

No = 1

Frequency of brushing/day Categorical

(Ordinal)

Twice or more = 0

Once or never = 1

Flossing Categorical

(Nominal)

Yes or sometimes = 0

No= 1

Self-perceived oral health status Categorical

(Ordinal)

Excellent, very good or good = 0

Fair or poor= 1

OHLI reading weighted score Continuous 0-50

OHLI numeracy weighted score Continuous 0-50

OHLI total score Continuous 0-100

OHLI level

(Oral health literacy level)

Categorical

(Ordinal)

Adequate = 0

Marginal or Inadequate = 1

CCOHLI score Continuous 0-4

CCOHLI level


Categorical

(Ordinal)

Adequate= 0

Inadequate = 1

REALD-30 score Continuous 0-30

REALD-30 level


Categorical

(Ordinal)

High = 0

Marginal or Low = 1


81

Knowledge test weighted score Continuous 0-100

IPC sub-scale score (for each sub-

scale) Continuous 1-5

IPC rating (for each sub-scale) Categorical

(Ordinal)

Good =1

Poor = 0

Q1 of the barrier questionnaire

(received dental information

during the initial visit to the

Faculty)

Categorical

(Nominal)

Yes =0

No =1


(How did you receive the

information)

Categorical

(Nominal)

Verbally =0

In writing (e.g. pamphlet) =1

Electronically = 2


(Did you understand the

information that was given to

you?)

Categorical

(Nominal)

Yes =0

No =1


(Reasons for not understanding the

information?)

Categorical

(Nominal)

Complicated information =0

Dentist did not spend enough time to clarify =1

Dentist used terms that I did not understand = 2

Clinical area was noisy and distractive = 3

I was embarrassed to ask for clarification = 4


(Were you given time to ask

questions?)

Categorical

(Nominal)

Yes =0

No =1


(Were all the questions answered

to your satisfaction?)

Categorical

(Nominal)

Yes =0

No =1


(Did you receive instructions about

improving your oral hygiene?)

Categorical

(Nominal)

Yes =0

No =1

Q8 of the barrier questionnaire (Do

you plan to follow these

instructions?)

Categorical

(Nominal)

Yes =0

No =1


(Reason for not following the oral

hygiene instructions?)

Categorical

(Nominal)

I cannot see the values of the instructions =0

I do not that the instructions will help =1

I do not have time to perform these practices = 2

The cost of oral hygiene aids is high = 3

My teeth hurt when I brush them = 4

My gum bleeds when I brush my teeth = 5

82

Results

83

Part 1 and part 2:

Sample Characteristics

Descriptive statistics of the sample characteristics are summarized in Table 8. Participants’

ages ranged between 19 and 75 years, with a mean of 46.80 ± 14.12 years. Only 11% of the

participants were older than 65 years. Most participants were male (54.5%) and had college or

university education (39%). A majority of the sample reported English (73%) as their native

language and lived in Canada for more than 10 years (81%). Seventy-three percent of the

sample reported an annual household income of less than $40,000. A majority of the

participants attended the Faculty of Dentistry Clinics to treat their dental problems (79%).

Dentists were the source of dental information for 47% of the participants. A majority of the

patients (76%) reported that they ask the dental health professionals for advice if they have

dental problems. Fifty-four percent reported visiting their dental care provider once during the

last 12 months, while only 34% reported visiting their dentists regularly. Ninety-eight percent of

the sample reported owning a toothbrush and 66% indicated that they brush their teeth twice

daily. Forty-four percent of the sample stated that they floss their teeth, while 31% stated that

they sometimes floss their teeth. Nearly 3 in 4 participants (73%) reported that they do not have

insurance to cover their dental treatment. Just over half of the sample reported fair or poor oral

health status, while only 6% reported excellent oral health status.

Communicative and Critical Oral Health Literacy Scores

The scores for each item of the communicative and critical OHL scale are presented in Table

9. The vast majority of the participants selected “sometimes” or “often” to describe their

communicative and critical oral health literacy skills. Both graphical and statistical evaluations of

the CCOHLI scores revealed a negative skewness of the distributions and departure from

normality (Table 10). The mean communicative OHLI score was 2.87 ± 0.69 and the mean critical

OHLI score was 2.95 ± 0.81. More than half of the participants had adequate (mean score ≥3)

communicative or critical oral health literacy (55% and 64%, respectively). The mean CCOHLI

score was 2.91 ± 0.67 and about 55% of the participants had adequate (mean CCOHLI score≥3)

communicative and critical oral health literacy combined together (Table 10).

84

OHLI, REALD-30, REALM and Oral Health Knowledge Test Scores

Both graphical and statistical evaluations of the OHLI (Table 11), oral health knowledge test

(Table 12), REALD-30 (Table 13) and REALM (Table 13) scores revealed a negative skewness of

the distributions and departure from normality. The mean scores of OHLI, REALD-30 and REALM

were high (81.38 ± 10.70, 23.35 ± 5.03 and 61.58 ± 7.76, respectively), while the mean

knowledge score was 52.17 ± 22.25, indicating a low to moderate level of oral health knowledge

among the sample, but a high level of dental and medical literacy. Similarly, the mean scores for

both the reading comprehension and numeracy OHLI components were also high with mean

scores of 41.86 ± 5.75 and 39.93 ± 6.82, respectively. More than two-thirds of the participants

(69%) had an adequate level of oral health literacy, measured using a functional oral health

literacy instrument (OHLI), while only approximately 38% of the participants had a high level of

oral health literacy, measured using a word-recognition test (REALD-30). In contrast to the

REALD-30, REALM, which evaluates word recognition ability in the medical field, identified about

78% of the participants with adequate level of health literacy.

Convergent and discriminant validity of CCOHLI and OHLI

Non-parametric bivariate correlations between CCOHLI, OHLI, REALM, REALD-30, and

knowledge test are summarized in Table 14. Convergent validity of CCOHLI was supported by a

weak statistically significant positive correlation between CCOHLI and REALD-30 scores

(Spearman’s rho=0.158, p<0.05). On the other hand, the correlation between CCOHLI and OHLI

scores was not statistically significant. Discriminant validity of CCOHLI was established because

the correlation between CCOHLI and REALM was not statistically significant. Convergent validity

of OHLI was supported by a moderate statistically significant positive correlation between OHLI

and REALD-30 scores (Spearman’s rho=0.492, p<0.01). Discriminant validity of OHLI was

questionable due to a moderate statistically significant positive correlation that was found

between OHLI and REALM scores (Spearman’s rho=0.542, p<0.01).

Association between OHLI and socio-demographics, dental attendance, oral health

behaviors and self-perceived oral health status

Bivariate associations between different predictors and the OHLI score are presented in

Tables 15, 16 and 17. Bivariate analyses identified significant associations between the OHLI

85

(reading/numeracy/total) score and native language, time spent in Canada, and annual

household income. Those patients who reported English as their native language, lived in

Canada for more than 10 years, or had an annual income of $40,000 or higher had significantly

higher oral health literacy (mean OHLI score) than those who reported languages other than

English as their native language, lived in Canada for less than 10 years or had an annual income

less than $40,000. In contrast, the associations between OHLI scores and all the other variables

summarizing the socio-demographics, the participants’ dental attendance, oral health behaviors

and self-perceived oral health status were not statistically significant.

Using bivariate analyses between OHLI level and the above mentioned variables showed

similar relationships (Table 22).

Association between CCOHLI and socio-demographics, dental attendance, oral health


Bivariate associations between different predictors and the CCOHLI score are presented in

Table 18. Bivariate analyses revealed significant associations between CCOHLI score and reason

for last dental visit, attendance for regular dental check-up, frequency of tooth brushing and

flossing and self-perceived oral health status. Those participants who go to the dentist for

regular check-ups, brush their teeth twice/day or more or floss regularly or sometimes, had

significantly higher communicative and critical oral health literacy (mean CCOHLI score) than

those who do not visit a dentist for regular check-ups, brush their teeth once/day or never or do

not floss. In addition, participants who reported a reason other than emergency for their last

dental visit or reported excellent, very good or good oral health status had a significantly higher

mean CCOHLI score in comparison to those who reported emergency as a reason for their last

dental visit or reported fair or poor oral health status. In contrast, the associations between

CCOHLI scores and all the other variables summarizing the socio-demographics and the

participants’ dental attendance were not significant.

Similarly, significant associations were found between CCOHLI level and attendance for

regular dental check-ups, frequency of tooth brushing and self-perceived oral health status but

not between CCOHLI level and last dental visit nor the frequency of flossing (Table 23). Higher

percentages of participants who reported regular attendance for dental check-ups, higher

frequency of daily teeth brushing (two times or more) or excellent, very good or good oral

86

health status had an adequate communicative and critical oral health literacy (CCOHLI level)

compared to those who reported an irregular attendance for dental check-ups, a lower

frequency of teeth brushing (one time or never) or fair or poor oral health status.

Association between REALD-30 and socio-demographics, dental attendance, oral

health behaviors and self-perceived oral health status

Bivariate associations between different predictors and the REALD-30 score are presented

in Table 19. Bivariate analyses revealed no significant associations between REALD-3O scores

and all the variables summarizing the socio-demographics, participants’ dental attendance, oral

health behaviors and self-perceived oral health status. Similarly, no significant association was

found between REALD-30 level and all the above variables (Table 24).

Association between REALM and socio-demographics, dental attendance, oral health


Bivariate associations between different predictors and the REALM score are presented in

Table 20. Bivariate analyses revealed no significant associations between REALM scores and

most of the variables summarizing the socio-demographics, participants’ dental attendance, oral

health behaviors and self-perceived oral health status. Only two variables, native language and

time in Canada, were significantly associated with REALM scores. Participants who reported

English as their native language or lived in Canada for more than 10 years had significantly

higher health literacy (mean REALM score) than those who reported languages other than

English as their native language or lived in Canada for less than 10 years.

Similarly, significant associations were found between REALM level and native language

and time being in Canada (Table 25).

Association between oral health knowledge test and socio-demographics, dental

attendance, oral health behaviors and self-perceived oral health status

Bivariate associations between different predictors and the oral health knowledge test

scores are presented in Table 21. Bivariate analyses revealed no significant associations

between knowledge test score and most of the variables summarizing the socio-demographics,

participants’ dental attendance, oral health behaviors and self-perceived oral health status.

87

Native language was the only variable significantly associated with the knowledge test score.

Participants who reported English as their native language scored higher in the knowledge test

in comparison to those who reported languages other than English as their native language.

Association between oral health knowledge test and oral health literacy

The Spearman’s rho revealed moderate statistically significant positive association between

the knowledge test scores and both OHLI and REALD-30 scores (Spearman’s rho =0.493 and

0.395, respectively; p<0.01) and a weak statistically significant positive association between the

knowledge test scores and CCOHLI (Spearman’s rho =0.167, p<0.05) (Table 14). Participants with

adequate level of oral health literacy, measured using OHLI, REALD-30 and CCOHLI, had

significantly higher mean knowledge test score compared to those with lower level of oral

health literacy (Table 26).

Oral Health Impact Profile-14 (OHIP-14)

The distributions of responses to individual OHIP-14 items are given in Table 27. The most

commonly reported impacts were within the dimensions of physical pain, psychological

discomfort, and psychological disability. More than one-third of the participants reported

uncomfortable meals, being self-conscious or being embarrassed because of oral health

problems “fairly ⁄ very often” during the last 12 months. Similarly, more than one-third

experienced toothache “occasionally” during the last 12 months. On the other hand, only 6.3%

to 9.7% reported negative impacts “fairly⁄ very often” within the dimension of functional

limitation. Data on the prevalence, extent and severity of impacts by OHIP-14 dimensions and

total scale score are summarized in Table 28. Sixty-one percent reported one or more OHIP-14

items “fairly often” or ”very often”, with an overall mean of 2.89 items reported “fairly often” or

“very often”. The mean severity score, summed for the 14 items in the scale, was 18.65. The

dimensions of physical pain, psychological discomfort, and psychological disability accounted for

the highest prevalence, extent, and severity of impacts.

Association between Oral Health Impact Profile-14 (OHIP-14) and health or oral health

literacy

Non-parametric bivariate correlations between CCOHLI, OHLI, REALM, REALD-30 and OHIP-

88

14 severity and extent are summarized in Table 29. None of the instruments or their

components was significantly correlated with the OHIP-14 severity or extent. On the other hand,

significant correlations were found between some of OHIP-14 domains and some of the health

or oral health literacy instruments. Significant weak negative correlations were identified

between the functional domain of OHIP-14 (severity and extent) and OHLI, REALD-30 and

REALM scores. In addition, significant weak negative correlations were found between REALD-30

and the following domains: physical disability (extent), social disability (severity and extent) and

handicap (extent).

The bivariate associations between the prevalence of impacts and health or oral health

literacy levels are presented in Table 30. A significant association was found between the

prevalence of impacts and the communicative and critical oral health literacy level. Participants

with an inadequate communicative and critical oral health literacy level were more likely to

report negative oral-health-related impacts on quality of life (fairly ⁄ very often) in comparison

to participants with adequate communicative and critical oral health literacy level.

Association between dental caries and health or oral health literacy

The prevalence and severity of coronal caries are summarized in Table 31. The vast majority

of the study sample (about 99%) had experienced one or more decayed, missing or filled teeth

(DMFT score >0). About 80% of the participants in this study were diagnosed with at least 1

untreated dental caries at the time of examination. On average, participants in the study had

4.29 (SD=4.65) teeth with untreated decay, 3.55 (SD=4.84) missing teeth due to caries and 6.8

(SD=5.81) filled teeth, giving an average DMFT score of 14.65 (SD=6.79). On average, about 48%

(SD=29.37) of the teeth that experienced coronal tooth decay were successfully filled, 22%

(SD=24.34) were extracted but 30% (SD=27.85) were still untreated.

Non-parametric bivariate correlations between CCOHLI, OHLI, REALM, REALD-30,

knowledge test and the DMFT index scores are summarized in Table 32. Statistically significant

weak positive correlations were identified between the OHLI and its components and the

percentage of dental caries treated by fillings (FT/DMFT) and between the knowledge test score

and the number of filled teeth (FT). In addition, the OHLI numeracy weighted score was

significantly negatively correlated with the number of decayed/untreated teeth (DT) and the

percentage of untreated dental caries (DT/DMFT). No significant association was identified

89

between the other tests and the DMFT index.

The bivariate associations between the DMFT index scores and health or oral health levels

are presented in Tables 33, 34, 35 and 36. Significant associations were found between the

percentage of untreated dental caries (DT/DMFT) and the oral health literacy level (measured

using the CCOHLI and the REALD-30) and between the percentage of dental caries treated with

fillings (FT/DMFT) and the oral health literacy level (measured using the OHLI and the REALD-

30). Participants with high or adequate oral health literacy (measured using REALD-30 or

CCOHLI) had a lower mean percentage of untreated/decayed teeth (DT/DMFT) in comparison to

participants with marginal, inadequate or low oral health literacy level. In addition, participants

with high or adequate oral health literacy level had a higher mean percentage of decayed teeth

treated with fillings (FT/DMFT) in comparison to participants with marginal, inadequate or low

oral health literacy level. In contrast, the health literacy level (measured using REALM) was not

associated with the untreated decayed or filled components of the DMFT index but was

significantly associated with the percentage of decayed teeth treated with extraction

(MT/DMFT). Participants with adequate health literacy level had a lower mean percentage of

decayed teeth treated with extraction (MT/DMFT) in comparison to participants with marginal

or low health literacy.

Association between periodontal disease and health or oral health literacy

The distribution of participants according to their worst (deepest) probing scores ranging

from 0–3 mm to 6 mm or more can be seen in Table 37. Less than 7% of the participants had all

their pockets as 3mm or less. The percentages of participants with worst probing depth of 4, 5

and 6mm were 26%, 23% and 20%, respectively. About one quarter of the sample had at least

one probing depth more than 6 mm. Participants were dichotomized based on their worst

probing depth using the definition of periodontal disease by the U.S. National Center for Health

Statistics90 which defines periodontal disease as at least 1 periodontal pocket with a probing

depth of 4 mm or more and a loss of attachment at the same site of 3 mm or more. Bivariate

analyses identified no significant association between the oral health literacy level and the

prevalence of periodontal disease (Table 38).

90

Multivariate analyses to assess the association between different predictors and oral

health literacy

Multicollinearity diagnostics did not reveal any sign of severe interactions among the

predictors with VIF values <10 and tolerance values >0.4. Three logistic regression models were

developed to predict the oral health literacy level from a set of predictors. The first model

evaluated the association between different predictors and the communicative and critical oral

health literacy level (Table 39). Only three of the variables (frequency of dental flossing, self-

perceived oral health status and any untreated caries) were significantly associated with the oral

health literacy level at the multivariate level. Individuals who did not floss, reported fair or poor

oral health status or experienced untreated caries were 2.75, 3.68 and 4.34 times more likely to

have inadequate communicative and critical oral health literacy, respectively.

The second model evaluated the association between different predictors and the oral

health literacy level measured using OHLI (Table 40). Native language other than English, being

in Canada less than 10 years, failure to attend regular dental check-ups, low oral health

knowledge test score, having high OHIP-14 prevalence and having untreated dental caries were

significantly associated with inadequate or marginal oral health literacy.

The third model evaluated the association between different predictors and the oral health

literacy level measured using REALD-30 (Table 41). Only two of the variables (time of last dental

visit and dental knowledge score) were significantly associated with the oral health literacy

level. Participants who did not visit the dentist during the last 12 months were 60% less likely to

have marginal or low oral health literacy level. Also participants with low knowledge test score

were more likely to have marginal or low oral health literacy level

Internal Reliability of CCOHLI

The Cronbach’s alpha values were high (>0.8) for the CCOHLI and its components (Table

42). These high values, which reflect a high internal reliability of the instruments, did not

increase significantly with the sequential deletion of test items.

Test-retest Reliability of CCOHLI

The ICC values for the CCOHLI and the communicative section (>0.6) reflect a good

agreement between test and retest results, while the ICC value for the critical oral health

91

literacy section was (0.582), reflecting a moderate agreement between the test and retest

results (Table 43).

92

Results tables for

Part 1

Development and Validation of Critical and Communicative

Oral Health Literacy Instrument (CCOHLI)

Part 2

Further Validation of Oral Health Literacy Instrument (OHLI)

93

Table 8: Sample characteristics (n=178)

Age

Mean age ( ± SD) 46.80 ( ± 14.12)

Min. 19

Max. 75

Missing 0

Frequencies

% Valid % n

Age groups

18-24 5.6 5.6 10

25-44 38.8 38.8 69

45-64 44.4 44.4 79

65+ 11.2 11.2 20

Missing - - -

Sex

Female 45.5 45.5 81

Male 54.5 54.5 97

Missing - - -

Language

English 71.3 72.6 127

Others 27 27.4 48

Missing 1.7 - 3

Duration being in Canada

Less than 5 years 11.2 11.4 20

5-10 years 7.9 8.0 14

More than 10 years 79.2 80.6 141

Missing 1.7 - 3

Education level

High school or less 15.7 15.9 28

Some college degree 24.2 24.4 43

College or university degree 39.3 39.8 70

Postgraduate education 19.7 19.9 35

Missing 1.1 - 2

Income

Less than 20,000$ 32.6 33.7 58

20,000-39,000$ 37.6 39 67

40,000-59,000$ 16.3 16.9 29

60,000-79,000$ 7.9 8.1 14

More than 80,000$ 2.2 2.3 4

Missing 3.4 - 6


94

Reason for being a patient at the faculty

Referred by the dentist 5.1 5.1 9

Treat dental emergency 6.2 6.3 11

Treat dental problem 77.5 78.9 138

Check up 9.6 9.7 17

Missing 1.7 - 3

Source of dental information

Never looked for dental information 16.3 16.5 29

Dentist 46.1 46.6 82

Other health professionals 14.6 14.8 26

Media 14.6 14.8 26

Internet 26.4 26.7 47

Other 8.4 8.5 15

Missing 1.1 - 2

Ask for advice

Family 12.9 13.1 23

Friend 10.7 10.8 19

Family physician 10.7 10.8 19

Dental health professionals 74.7 75.6 133

My self 10.7 10.8 19

Other 5.1 5.1 9

Missing 1.1 - 2

Last dental visit

During the last 12 months 53.4 54.3 95

More than 12 months ago 43.3 44.0 77

Never 1.7 1.7 3

Missing 1.7 - 3

Reason for last visit

Check up 24.7 25.4 44

Emergency 34.8 35.8 62

Scheduled dental treatment 28.1 28.9 50

Consultation 9 9.2 16

Missing 1.7 - 3

Visit the dentist regularly

Yes 33.1 34.1 59

No 64 65.9 114

Missing 2.8 - 5

Own toothbrush

Yes 97.2 98.3 173

No 1.7 1.7 3

Missing 1.1 - 2


95

Frequency of Brushing teeth daily

Once 17.4 17.7 31

Twice 64.6 65.7 115

More than twice 15.2 15.4 27

Never 1.1 1.1 2

Missing 1.7 - 3

Flossing

Yes 43.3 44.0 77

Sometimes 30.9 31.4 55

No 24.2 24.6 43

Missing 1.7 - 3

Pay for dental treatment

Insurance from work 12.4 12.5 22

Governmental assistant 9.6 9.7 17

My self (no insurance) 72.5 73.3 129

Combination of (insurance from work or governmental assistance and myself)

6.8 6.82 12

Other 4.5 4.5 8

Missing 1.1 - 2

Self-perceived oral health status

Excellent 5.6 6.0 10

Very good 10.7 11.4 19

Good 29.2 31.1 52

Fair 24.2 25.7 43

Poor 24.2 25.7 43

Missing 6.2 - 11

96

Table 9. Frequency of responses for the test of Communicative and Critical Oral Health Literacy

(CCOHLI) (n =174)

Component % (n)

Never Rarely Sometimes Often

Co

mm

un

icat

ive

Ora

l He

alth

Lite

racy

You have collected oral health related information from various sources.

23 (40) 21.3 (37) 40.8 (71) 14.9 (26)

You have extracted the oral health information you want.

15.5 (27) 19.5 (34) 46 (80) 19 (33)

You have understood the obtained oral health information.

8 (14) 8.6 (15) 35.1 (61) 48.3 (84)

You have communicated your thoughts about your oral health to someone.

6.3 (11) 19 (33) 47.1 (82) 27.6 (48)

You have applied the obtained information to your daily life.

6.9 (12) 11.5 (20) 54.6 (95) 27 (47)

Cri

tica

l Ora

l He

alth

Lite

racy

You have considered whether the information was applicable to your situation.

9.2 (16) 9.8 (17) 47.1 (82) 33.9 (59)

You have considered the credibility of the information.

10.3 (18) 13.8 (24) 35.6 (62) 40.2 (70)

You have checked whether the information was valid and reliable.

14.9 (26) 14.4 (25) 37.9 (66) 32.8 (57)

You have collected information to make oral health-related decisions.

16.1 (28) 13.8 (24) 43.1 (75) 27 (47)

97

Table 10. Subscales and total Mean scores for the test of Communicative and Critical Oral Health

Literacy (CCOHLI) (n =174)

Communicative OHLI Critical OHLI CCOHLI

Mean ( ± SD) 2.87 (.69) 2.95 (.81) 2.91 (.67)

Min. 1 1 1

Max. 4 4 4

Median 3 3 3

Adequate % (n)* 54.6 (95) 64.4 (112) 55.2 (96)

Inadequate % (n)** 45.4 (79) 35.6 (62) 44.8 (78)

* Adequate (score ≥3)

** Inadequate (score <3)

98

Table 11. Subscales and total Mean scores for OHLI and its components (n =169)

* Adequate scores between (80-100)

** Marginal scores between (65-79) *** Inadequate scores between (0-64)

Reading comprehension Numeracy OHLI

Mean ( ± SD) 41.86 ( ± 5.75) 39.93 ( ± 6.82) 81.38 ( ± 10.70)

Min. 15.79 7.89 40.79

Max. 50 50 97.37

Median 43.42 39.93 84.21

Adequate % (n)* - - 68.6 (116)

Marginal % (n)** - - 23.7 (40)

Inadequate % (n)*** - - 7.7 (13)

99

Table 12. Subscales and total Mean scores for Oral Health Knowledge test (n =176)

Knowledge test

Mean ( ± SD) 52.17 ( ± 22.25)

Min. 5.88

Max. 100

Median 52.94

100

Table 13. Subscales and total Mean scores for REALD-30 and REALM scores (n =172)

REALD-30 REALM

Mean ( ± SD) 23.35 ( ± 5.03) 61.58 ( ± 7.76)

Min. 0 10

Max. 30 66

Median 24 64

% (n) % (n) High 37.8 (65) Adequate 77.9 (134)

Marginal 33.1 (57) Marginal 18.6 (32)

Low 29.1 (50) Low 3.5 (6)

101

Table 14. Spearman’s correlation between CCOHLI and OHLI and their components, knowledge test REALM and REALD

Communicative

OHLI Score

Critical OHLI

Score Score CCOHLI

OHLI reading

weighted score

OHLI numeracy

weighted score

OHLI total

score

Knowledge

weighted score REALD-30 score REALM score

Communicative OHLI

Score

Correlation

Coefficient 1.000 .548** .885** .167* .127 .165* .192* .149 .124

Critical OHLI Score Correlation

Coefficient .548** 1.000 .854** -.023 .137 .088 .038 .090 .037

Score CCOHLI Correlation

Coefficient .885** .854** 1.000 .102 .149 .148 .167* .158* .101

OHLI reading weighted

score

Correlation

Coefficient .167* -.023 .102 1.000 .390** .739** .525** .547** .551**

OHLI numeracy weighted

score

Correlation

Coefficient .127 .137 .149 .390** 1.000 .881** .271** .345** .400**

OHLI total score Correlation

Coefficient .165* .088 .148 .739** .881** 1.000 .439** .492** .542**

Knowledge weighted

score

Correlation

Coefficient .192* .038 .167* .525** .271** .439** 1.000 .395** .459**

REALD-30 score Correlation

Coefficient .149 .090 .158* .547** .345** .492** .395** 1.000 .760**

REALM score Correlation

Coefficient .124 .037 .101 .551** .400** .542** .459** .760** 1.000

The values in gray font are replica of the values in black font, therefore, all the values will be found in black.

* Correlation is significant at the 0.05 level (2-tailed).

** Correlation is significant at the 0.01 level (2-tailed).

102

Table 15. Association between OHLI reading score and some predictors

OHLI reading Score

Mean SD Standard

Error Median p value*

Age

18-24 years old 42.63 3.78 1.2 43.42

0.794** 25-44 years old 41.58 5.42 0.66 43.42

45-64 years old 42 6.03 0.69 43.42

+65 years old 41.41 6.76 1.55 44.74

Gender

Females 41.17 6.7 0.75 43.42 0.555

Males 42.36 4.73 0.49 43.42

Language

English 42.55 5.75 0.51 43.42 <0.001

Other 39.97 5.16 0.77 40.79

Time being in Canada

10 years or more 42.36 5.36 0.46 43.42 0.029

Less than 10 years 39.72 6.65 1.18 40.79

Education level

College degree or more 41.9 5.63 0.56 43.42 0.893

Less than college degree 41.64 5.99 0.72 43.42

Annual income

$40,000 or more 42.75 4.2 0.61 43.42 0.508

Less than $40,000 41.4 6.29 0.57 43.42

Last dental visit

In the last 12 months 41.69 5.41 0.56 43.42 0.279

More than 12 months or never 41.95 6.22 0.7 43.42

Reason for last dental visit

Others 41.8 5.66 0.54 43.42 0.974

Emergency 42.08 5.12 0.67 43.42


Yes 41.36 6.55 0.86 43.42 0.769

No 41.95 5.39 0.51 43.42

Ownership of tooth brush

Yes 41.78 5.78 0.45 43.42 0.896

No 42.11 5.74 3.31 44.74

Frequency of brushing

Twice or more 41.78 5.81 0.49 43.42 0.979

Once or never 41.69 5.71 1.01 43.42

Frequency of flossing

Yes or sometimes 41.53 5.97 0.53 43.42 0.540

No 42.48 5.13 0.79 43.42


Excellent, very good or good 42.06 5.62 0.63 43.42 0.607

Fair or poor 41.77 5.81 0.64 43.42

*p value obtained from Mann-Whitney U test for all independent variables except age.

**p value obtained from Kruskal-Wallis test for age groups.

103

Table 16. Association between OHLI numeracy score and some predictors

OHLI numeracy Score

Mean SD Standard


Age

18-24 years old 39.74 3.39 1.07 40.79

0.919** 25-44 years old 39.2 7.08 0.87 39.47

45-64 years old 39.89 6.6 0.76 39.47

+65 years old 38.29 8.08 1.81 40.79

Gender

Females 40.25 6.69 0.76 42.11 0.076

Males 38.75 6.86 0.71 39.47

Language

English 40.09 6 0.54 39.47 0.136

Other 37.81 8.49 1.25 39.47


10 years or more 40.43 6.2 0.53 42.11 <0.001

Less than 10 years 35.36 7.88 1.39 36.84

Education level



Annual income

$40,000 or more 42.22 5.05 0.75 42.11 0.001

Less than $40,000 38.3 7.2 0.65 39.47

Last dental visit




Others 39.67 6.99 0.68 39.47 0.435

Emergency 38.96 6.81 0.87 39.47


Yes 40.11 6.38 0.84 42.11 0.353

No 39.01 7.15 0.69 39.47


Yes 39.39 6.85 0.53 39.47 0.784

No 40.35 8.04 4.64 42.11


Twice or more 39.42 7.08 0.6 39.47 0.771

Once or never 39.13 5.76 1.03 39.47


Yes or sometimes 39.07 7.04 0.62 39.47 0.240

No 40.33 6.12 0.97 42.11



Fair or poor 39.09 6.92 0.76 39.47



104

Table 17. Association between OHLI total score and some predictors

OHLI Total Score

Mean SD Standard


Age

18-24 years old 82.37 4.97 1.57 83.55

0.758** 25-44 years old 80.9 10.1 1.24 83.55

45-64 years old 82.09 10.96 1.27 84.21

+65 years old 79.78 13.97 3.2 84.21

Gender

Females 81.6 11.45 1.3 85.53 0.263

Males 81.21 10.1 1.05 82.89

Language

English 82.71 10.14 0.92 84.21 0.019

Other 78.11 11.37 1.71 81.58


10 years or more 82.94 10.1 0.87 84.21 <0.001

Less than 10 years 75.17 10.78 1.94 75

Education level



Annual income

$40,000 or more 85.13 6.79 1 85.53 0.008

Less than $40,000 79.78 11.71 1.08 82.89

Last dental visit




Others 81.57 10.64 1.04 84.21 0.788

Emergency 81.28 10.71 1.41 83.55


Yes 81.6 11.13 1.47 84.21 0.754

No 81.12 10.72 1.04 84.21


Yes 81.33 10.75 0.84 84.21 0.668

No 82.46 13.7 7.91 86.84


Twice or more 81.42 10.85 0.93 84.21 0.433

Once or never 80.65 10.47 1.88 82.89


Yes or sometimes 80.8 11.43 1.02 84.21 0.261

No 82.8 8.19 1.29 85.53



Fair or poor 80.99 11 1.23 82.89



105

Table 18. Association between CCOHLI score and some predictors

CCOHLI Score

Mean SD Standard


Age

18-24 years old 2.57 0.6 0.19 2.78

0.283** 25-44 years old 2.95 0.62 0.07 3

45-64 years old 2.94 0.66 0.08 3.06

+65 years old 2.81 0.85 0.19 3.11

Gender

Females 2.87 0.61 0.07 3 0.414

Males 2.94 0.71 0.07 3

Language

English 2.9 0.71 0.06 3 0.901

Other 2.94 0.55 0.08 3


10 years or more 2.87 0.69 0.06 3 0.196

Less than 10 years 3.06 0.54 0.09 3.06

Education level

College degree or more 2.92 0.62 0.06 3 0.892

Less than college degree 2.9 0.73 0.09 3

Annual income

$40,000 or more 2.99 0.58 0.09 3 0.580

Less than $40,000 2.88 0.7 0.06 3

Last dental visit

In the last 12 months 2.88 0.73 0.07 3 0.948

More than 12 months or never 2.94 0.59 0.07 3


Others 2.99 0.65 0.06 3.11 0.035

Emergency 2.78 0.7 0.09 2.89


Yes 3.11 0.57 0.07 3.22 0.004

No 2.8 0.7 0.07 2.89


Yes 2.91 0.67 0.05 3 0.759

No 3 0.68 0.39 3.33


Twice or more 2.99 0.64 0.05 3.11 <0.001

Once or never 2.55 0.67 0.12 2.67


Yes or sometimes 2.98 0.66 0.06 3 0.006

No 2.68 0.65 0.1 2.67



Fair or poor 2.75 0.69 0.07 2.83



106

Table 19. Association between REALD-30 score and some predictors

REALD-30 Score

Mean SD Standard


Age

18-24 years old 23 3 1 23

0.438** 25-44 years old 24 4 1 24

45-64 years old 23 6 1 24

+65 years old 25 5 1 26

Gender

Females 23 5 1 24 0.506

Males 24 5 0 25

Language

English 24 5 0 24 0.219

Other 23 5 1 24


10 years or more 24 5 0 24 0.379

Less than 10 years 23 5 1 23

Education level

College degree or more 24 5 0 24 0.482

Less than college degree 23 6 1 24

Annual income

$40,000 or more 24 4 1 25 0.140

Less than $40,000 23 5 0 24

Last dental visit

In the last 12 months 23 5 0 24 0.099

More than 12 months or never 24 6 1 25


Others 23 5 0 24 0.711

Emergency 23 5 1 24


Yes 23 5 1 24 0.806

No 23 5 1 24


Yes 23 5 0 24 0.247

No 20 6 3 20


Twice or more 23 5 0 24 0.722

Once or never 23 5 1 24


Yes or sometimes 23 5 0 24 0.450

No 24 4 1 25


Excellent, very good or good 24 5 1 24 0.589

Fair or poor 23 5 1 24



107

Table 20. Association between REALM score and some predictors

REALM Score

Mean SD Standard


Age

18-24 years old 64 2 1 64

0.580** 25-44 years old 61 8 1 64

45-64 years old 61 8 1 64

+65 years old 62 8 2 65

Gender

Females 61 8 1 64 0.310

Males 62 7 1 65

Language

English 62 7 1 65 0.001

Other 60 8 1 62


10 years or more 62 7 1 65 0.002

Less than 10 years 58 10 2 61

Education level

College degree or more 62 7 1 64 0.572

Less than college degree 62 9 1 65

Annual income

$40,000 or more 62 7 1 65 0.555

Less than $40,000 61 8 1 64

Last dental visit

In the last 12 months 61 7 1 64 0.138

More than 12 months or never 62 9 1 65


Others 62 7 1 64 0.668

Emergency 62 6 1 64


Yes 62 7 1 64 0.724

No 61 8 1 64


Yes 62 8 1 64 0.599

No 56 14 8 63


Twice or more 61 8 1 65 0.530

Once or never 62 6 1 63


Yes or sometimes 61 8 1 64 0.605

No 62 6 1 65


Excellent, very good or good 61 8 1 65 0.982

Fair or poor 62 8 1 64



108

Table 21. Association between oral health knowledge test score and some predictors

Knowledge Test

Mean SD Standard


Age

18-24 years old 45.88 19.17 6.06 38.24

0.656** 25-44 years old 51.21 23.11 2.8 50

45-64 years old 53.62 22.95 2.6 58.82

+65 years old 52.94 18.31 4.09 50

Gender

Females 51.05 22.08 2.45 52.94 0.694

Males 53.13 22.46 2.3 52.94

Language

English 55.51 21.1 1.88 58.82 0.001

Other 43.8 23.23 3.39 41.18


10 years or more 53.74 21.02 1.78 58.82 0.054

Less than 10 years 46.35 26.42 4.6 41.18

Education level

College degree or more 51 23.79 2.34 47.06 0.373


Annual income

$40,000 or more 54.44 21.44 3.13 58.82 0.468

Less than $40,000 51.84 22.42 2.02 52.94

Last dental visit




Others 53.37 22.48 2.15 52.94 0.401

Emergency 49.76 22.02 2.82 52.94


Yes 51.15 24.58 3.2 47.06 0.688

No 52.31 21.21 2 52.94


Yes 52.12 22.49 1.72 52.94 0.866

No 54.9 3.4 1.96 52.94


Twice or more 51.36 22.22 1.87 52.94 0.351

Once or never 55.51 23 4.07 58.82


Yes or sometimes 53.84 23.11 2.02 58.82 0.1

No 46.78 19.09 2.95 41.18



Fair or poor 51.68 20.6 2.25 52.94



109

Table 22. Chi square analysis between OHLI and some predictors

OHLI

Adequate Marginal/

Inadequate OR 95% CI

p value

n % n % Lower Upper

Age

18-24 years old 8 80.0% 2 20.0% 0.535 0.105 2.747 0.714*

25-44 years old 45 68.2% 21 31.8% Ref. - -

45-64 years old 51 68.9% 23 31.1% .966 0.473 1.975 0.925

+65 years old 12 63.2% 7 36.8% 1.25 0.43 3.631 0.681

Gender

Females 53 68.8% 24 31.2% 1.017 .529 1.952 0.961

Males 63 68.5% 29 31.5%

Language

English 91 74.6% 31 25.4% 2.680 1.307 5.497 0.006

Other 23 52.3% 21 47.7%


10 years or more 100 74.1% 35 25.9% 3.469 1.551 7.762 0.002

Less than 10 years 14 45.2% 17 54.8%

Education level

College degree or more 67 68.4% 31 31.6% 1.012 .522 1.960 0.973

Less than college degree 47 68.1% 22 31.9%

Annual income

$40,000 or more 39 84.8% 7 15.2% 3.434 1.416 8.331 0.005

Less than $40,000 73 61.9% 45 38.1%

Last dental visit

In the last 12 months 62 69.7% 27 30.3% 1.104 .572 2.130 0.768

More than 12 months or never 52 67.5% 25 32.5%


Others 69 65.7% 36 34.3% .730 .362 1.474 0.380

Emergency 42 72.4% 16 27.6%


Yes 41 71.9% 16 28.1% 1.354 .671 2.732 0.396

No 70 65.4% 37 34.6%


Yes 112 68.3% 52 31.7% 1.077 .095 12.146 1.000*

No 2 66.7% 1 33.3%


Twice or more 93 68.9% 42 31.1% 1.218 .536 2.768 0.638

Once or never 20 64.5% 11 35.5%


Yes or sometimes 83 65.9% 43 34.1% .643 .288 1.439 0.281

No 30 75.0% 10 25.0%


Excellent, very good or good 57 73.1% 21 26.9% 1.462 .741 2.883 0.272

Fair or poor 52 65.0% 28 35.0%

* p value obtained from Fisher exact test

110

Table 23. Chi square analysis between CCOHLI and some predictors

CCOHLI

Adequate Inadequate OR

95% CI p value

n % n % Lower Upper

Age

18-24 years old 2 20.0% 8 80.0% 2.625 0.451 15.384 .266*

25-44 years old 39 56.5% 30 43.5% Ref. - - -

45-64 years old 44 57.9% 32 42.1% 0.9 .276 2.934 .861

+65 years old 11 57.9% 8 42.1% 2.8 0.701 11.183 0.213*

Gender

Females 42 52.5% 38 47.5% .819 .449 1.491 0.513

Males 54 57.4% 40 42.6%

Language

English 69 55.2% 56 44.8% 1.043 .534 2.034 0.903

Other 26 54.2% 22 45.8%


10 years or more 75 54.0% 64 46.0% .820 .384 1.754 0.609

Less than 10 years 20 58.8% 14 41.2%

Education level

College degree or more 57 54.8% 47 45.2% .964 .524 1.773 0.906


Annual income

$40,000 or more 27 58.7% 19 41.3% 1.170 .590 2.322 0.653

Less than $40,000 68 54.8% 56 45.2%

Last dental visit

In the last 12 months 51 53.7% 44 46.3% .896 .490 1.636 0.720



Others 65 60.2% 43 39.8% 1.720 .916 3.231 0.090

Emergency 29 46.8% 33 53.2%


Yes 39 67.2% 19 32.8% 2.165 1.118 4.192 0.021

No 55 48.7% 58 51.3%


Yes 94 55.0% 77 45.0% .610 .054 6.859 1.000*

No 2 66.7% 1 33.3%


Twice or more 83 59.3% 57 40.7% 2.548 1.162 5.589 0.017

Once or never 12 36.4% 21 63.6%


Yes or sometimes 119 91.5% 11 8.5% 2.104 .760 5.824 0.157*

No 36 83.7% 7 16.3%


Excellent, very good or good 54 69.2% 24 30.8% 3.125 1.641 5.950 <0.001

Fair or poor 36 41.9% 50 58.1%


111

Table 24. Chi square analysis between REALD-30 and some predictors

REALD-30

High Marginal/

Low OR 95% CI

p value

n % n % Lower Upper

Age

18-24 years old 2 20.0% 8 80.0% 1.957 0.383 1 0.716*

25-44 years old 22 32.8% 45 67.2% Ref. - -

45-64 years old 30 40.0% 45 60.0% 0.733 0.369 1.459 .376

+65 years old 11 55.0% 9 45.0% 0.4 0.145 1.107 0.073

Gender

Females 28 35.9% 50 64.1% .863 .464 1.605 0.641

Males 37 39.4% 57 60.6%

Language

English 52 42.3% 71 57.7% .863 .464 1.605 0.096

Other 13 28.3% 33 71.7%


10 years or more 56 40.9% 81 59.1% 1.767 .761 4.103 0.182

Less than 10 years 9 28.1% 23 71.9%

Education level



Annual income

$40,000 or more 21 45.7% 25 54.3% 1.580 .792 3.151 0.193

Less than $40,000 42 34.7% 79 65.3%

Last dental visit




Others 41 39.0% 64 61.0% 1.136 .591 2.183 0.703

Emergency 22 36.1% 39 63.9%


Yes 24 41.4% 34 58.6% 1.267 .659 2.434 0.477

No 39 35.8% 70 64.2%


Yes 64 38.3% 103 61.7% 1.243 .110 13.984 1.000*

No 1 33.3% 2 66.7%


Twice or more 52 37.7% 86 62.3% .957 .430 2.132 0.915

Once or never 12 38.7% 19 61.3%


Yes or sometimes 47 36.4% 82 63.6% .775 .377 1.597 0.490

No 17 42.5% 23 57.5%



Fair or poor 28 34.1% 54 65.9%


112

Table 25. Chi square analysis between REALM and some predictors

REALM

Adequate Marginal/

Low OR 95% CI

p value

n % n % Lower Upper

Age

18-24 years old 10 100.0% 0 0.0% - - - .106*

25-44 years old 50 74.6% 17 25.4% Ref. - - -

45-64 years old 57 76.0% 18 24.0% 0.929 0.433 1.994 .850

+65 years old 17 85.0% 3 15.0% 0.519 0.135 1.992 0.545*

Gender

Females 56 71.8% 22 28.2% .522 .252 1.083 0.078

Males 78 83.0% 16 17.0%

Language

English 102 82.9% 21 17.1% 2.590 1.203 5.580 0.013

Other 30 65.2% 16 34.8%


10 years or more 113 82.5% 24 17.5% 3.221 1.402 7.401 0.004

Less than 10 years 19 59.4% 13 40.6%

Education level



Annual income

$40,000 or more 36 78.3% 10 21.7% 1.084 .478 2.456 0.847

Less than $40,000 93 76.9% 28 23.1%

Last dental visit




Others 83 79.0% 22 21.0% 1.230 .582 2.601 0.578

Emergency 46 75.4% 15 24.6%


Yes 46 79.3% 12 20.7% 1.201 .554 2.601 0.642

No 83 76.1% 26 23.9%


Yes 130 77.8% 37 22.2% 1.757 .155 19.916 0.534*

No 2 66.7% 1 33.3%


Twice or more 107 77.5% 31 22.5% 1.007 .396 2.557 0.989

Once or never 24 77.4% 7 22.6%


Yes or sometimes 99 76.7% 22 23.3% .825 .344 1.981 0.667

No 32 80.0% 16 20.0%


Excellent, very good or good 61 77.2% 18 22.8% .886 .419 1.875 0.752

Fair or poor 65 79.3% 17 20.7%


113

Table 26. Association between health literacy or oral health literacy level and oral health knowledge

test score

Oral health Knowledge Test

Mean SD Standard

Error Median p value *

CCOHLI level (n= 172)

Adequate 56.56 21.85 2.23 58.82 0.006

Inadequate 47.45 21.59 2.48 41.18

OHLI level (n= 169)

Adequate 58.77 19.6 1.82 58.82 <0.001

Marginal and Inadequate 40.18 22.21 3.05 35.29

REALD-30 level (n= 172)

High 60.63 20.74 2.57 58.82 <0.001

Marginal and Low 47.33 22 2.13 47.06

REALM level (n=172)

Adequate 57.37 20.34 1.76 58.82 <0.001

Marginal and Low 34.67 20.6 3.34 29.41

* p value obtained from Mann-Whitney U test.

114

Table 27. Frequency of responses to individual OHIP-14 items and mean items score (n=175)

Dimension and description of item (because of trouble with your teeth, mouth or dentures during the last 4 weeks,…)

Distribution of responses % (n)

Never/ Hardly ever

Occasionally Fairly often/ Very

often Mean (SD)

Functional limitation

Have you had trouble pronouncing any words because of problems with limitation your teeth, mouth or dentures?

83.4 (146) 6.9 (12) 9.7 (17) 0.59 (1.15)

Have you felt that your sense of taste has worsened because of problems with your teeth, mouth or dentures?

77.1 (135) 16.6 (29) 6.3(11) 0.75 (1.07)

Physical pain

Have you had painful aching in your mouth? 45.1 (79) 35.4 (62) 19.4 (34) 1.63 (1.20)

Have you found it uncomfortable to eat any foods because of problems with your teeth, mouth or dentures?

29.1 (51) 32.0 (56) 38.9 (68) 2.2 (1.32)

Psychological discomfort

Have you been self-conscious because of your teeth, mouth or dentures?

34.9 (61) 21.1 (37) 44.0 (77) 2.22 (1.52)

Have you felt tense because of problems with your teeth, mouth or dentures?

46.9 (82) 25.7 (45) 27.4 (48) 1.71 (1.37)

Physical disability

Has your diet been unsatisfactory because of problems with your teeth, mouth or dentures?

66.3 (116) 17.1 (30) 16.6 (29) 1.13 (1.36)

Have you had to interrupt meals because of problems with your teeth, mouth or dentures?

65.1 (114) 17.7 (31) 17.1 (30) 1.17 (1.32)

Psychological disability

Have you found it difficult to relax because of problems with your teeth, mouth or dentures?

56.6 (99) 23.4 (41) 20.0 (35) 1.39 (1.36)

Have you been a bit embarrassed because of problems with your teeth, mouth or dentures?

48.0 (84) 18.3 (32) 33.7 (59) 1.84 (1.52)

Social disability

Have you been a bit irritable with other people because of problems with your teeth, mouth or dentures?

64.0 (112) 19.4 (34) 16.6 (29) 1.11 (1.28)

Have you had difficulty doing your usual jobs because of problems with your teeth, mouth or dentures?

73.7 (129) 16.0 (28) 10.3 (18) 0.86 (1.17)

Handicap

Have you felt that life in general was less satisfying because of problems with your teeth, mouth or dentures?

57.7 (101) 22.9 (40) 19.4 (34) 1.38 (1.38)

Have you been totally unable to function because of problems with your teeth, mouth or dentures

81.7 (143) 8.6 (15) 9.7 (17) 0.66 (1.08)

115

Table 28. Prevalence, extent and severity of impacts by OHIP-14 subscale and total score (n=175)

Dimension Prevalence Extent Severity

% (n) Mean ( ± SD) Mean ( ± SD)

Functional limitation 11.4 (20) .16 (.48) 1.34 (1.97)

Physical pain 41.7 (73) .58 (.76) 3.83 (2.14)

Psychological discomfort 47.4 (83) .71 (.83) 3.93 (2.60)

Physical disability 22.3 (39) .34 (.67) 2.30 (2.5)

Psychological disability 37.1 (65) .54 (.76) 3.23 (2.56)

Social disability 18.3 (32) .27 (.61) 1.98 (2.31)

Handicap 21.1 (37) .29 (.61) 2.04 (2.22)

Total OHIP-14 score 61.7 (108) 2.89 (3.66) 18.65 (13.59)

116

Table 29. Spearman’s correlation between CCOHLI and OHLI and their components, REALM and REALD and OHIP-14 and its domains

Communicative

OHLI Score

Critical OHLI

Score Score CCOHLI

OHLI reading

weighted score

OHLI numeracy

weighted score OHLI total score REALD-30 score REALM score

OHIP-14 Severity Correlation

Coefficient -.030 -.013 -.037 -.111 .020 -.001 -.117 -.044

OHIP-14 Extent Correlation

Coefficient -.074 -.024 -.081 -.137 .016 -.027 -.089 -.023

OH

IP-1

4 s

eve

rity

Functional Correlation

Coefficient .008 .025 .017 -.297** -.076 -.175* -.314** -.280**

Physical Pain Correlation

Coefficient -.029 -.013 -.028 .036 .068 .083 -.010 -.017

Psychological

discomfort Correlation

Coefficient -.009 .047 -.005 -.042 .054 .032 -.047 .038

Physical disability Correlation

Coefficient -.008 .022 .005 -.167* -.031 -.060 -.141 -.072

Psychological disability Correlation

Coefficient .019 .028 .016 -.108 .021 .006 -.119 -.024

Social disability Correlation

Coefficient -.051 -.074 -.079 -.147 -.011 -.052 -.157* -.063

Handicap Correlation

Coefficient -.015 -.046 -.044 -.047 .041 .031 -.076 -.019

OH

IP-1

4 e

xte

nt

Functional Correlation

Coefficient -.065 -.022 -.067 -.271** -.068 -.160* -.216** -.189*

Physical Pain Correlation

Coefficient -.017 .005 -.011 -.088 -.045 -.062 -.059 -.078

Psychological

discomfort Correlation

Coefficient -.075 .034 -.054 -.047 .055 .025 -.013 .082

Physical disability Correlation

Coefficient .014 .035 .013 -.176* -.026 -.073 -.167* -.057

Psychological disability Correlation

Coefficient .011 .045 .010 -.110 .044 .007 -.121 -.012

Social disability Correlation

Coefficient -.037 -.002 -.030 -.239** .038 -.062 -.197* -.102

Handicap Correlation

Coefficient -.032 -.038 -.064 -.148 .003 -.058 -.202** -.105

* Correlation is significant at the 0.05 level (2-tailed). ** Correlation is significant at the 0.01 level (2-tailed).

117

Table 30. Chi square analysis between oral health literacy level and prevalence of oral impacts (fairly

often/very often) (as measured by OHIP-14)

Never/ Hardly ever /Occasionally

Fairly often/ Very often OR

95% CI p value

n % n % Lower Upper

CCOHLI Level

Adequate 44 45.8% 52 54.2% 1.987 1.056 3.737 0.032

Inadequate 23 29.9% 54 70.1%

OHLI Level

Adequate 44 38.6% 70 61.4% 0.928 0.475 1.813 0.827

Marginal and Inadequate 21 40.4% 31 59.6%

REALD-30 Level

High 26 40.0% 39 60.0% 1.067 0.566 2.011 0.842

Marginal and Low 40 38.5% 64 61.5%

REALM level

Adequate 51 77.3% 81 78.6% .923 .439 1.943 .834

Marginal and Low 15 22.7% 22 21.4$

118

Table 31. DMFT descriptive statistics (n=164)

Mean SD Median 95% CI

Lower Higher

DT* 4.29 4.65 2 3.62 5.07

MT** 3.55 4.84 2 2.84 4.35

FT 6.8 5.18 6 6.09 7.69

DMFT 14.65 6.79 14 13.80 15.86

DT/DMFT 29.83 27.85 21.11 25.51 34.15

MT/DMFT 22.21 24.34 16.66 18.44 25.99

FT/DMFT 47.96 29.37 50 43.40 52.51 Note:

No. of completely edentulous patients is 1

No. of patients with DMFT =0 are 2 *Prevalence of subjects with at least one untreated carious lesion= 80.5% **Prevalence of subjects with at least one missing tooth=66.1%

119

Table 32. Spearman’s correlation between DMFT and CCOHLI and OHLI and their components, knowledge test, REALM and REALD

Communicative

OHLI Score

Critical OHLI

Score Score CCOHLI

OHLI reading

weighted

score

OHLI

numeracy

weighted

score

OHLI total

score

Knowledge

weighted

score

REALD-30

score REALM score

DT

Correlation

Coefficient -0.088 -0.105 -0.119 -0.016 -0.18* -0.151 -0.002 -0.116 0.008

MT

Correlation

Coefficient 0.054 -0.03 -0.008 -0.039 -0.034 -0.025 -0.031 -0.025 -0.068

FT

Correlation

Coefficient 0.115 0.049 0.089 0.121 0.13 0.141 0.197* 0.082 0.081

DMFT

Correlation

Coefficient 0.12 -0.02 0.038 0.057 0.015 0.04 0.089 -0.005 0.081

DT/DMFT

Correlation

Coefficient -0.136 -0.105 -0.141 -0.035 -0.161* -0.135 -0.034 -0.139 -0.02

MT/DMFT

Correlation

Coefficient 0.049 -0.015 0.002 -0.105 -0.053 -0.059 -0.084 -0.02 -0.078

FT/DMFT

Correlation

Coefficient 0.084 0.124 0.126 0.157* 0.178* 0.191* 0.152 0.15 0.087


120

Table 33. Association between CCOHLI Level and the DMFT data

CCOHLI LEVEL

p value* Adequate Inadequate

Mean SD Standard error


DT 3.79 4.28 0.45 5.1 5.01 0.59 0.063

MT 3.71 5.29 0.56 3.11 3.79 0.45 0.731

FT 7.27 5.4 0.57 6.12 4.76 0.56 0.243

DMFT 14.76 6.96 0.74 14.33 6.68 0.79 0.654

DT/DMFT 26.6 27.13 2.89 35.08 28.12 3.34 0.029

MT/DMFT 22.36 23.86 2.54 21.07 23.74 2.82 0.654

FT/DMFT 51.04 29.19 3.11 43.85 28.75 3.41 0.100

*p value obtained from Mann-Whitney U test.

121

Table 34. Association between OHLI Level and the DMFT data

OHLI LEVEL

p value* Adequate Marginal or Inadequate



DT 4.02 4.72 0.45 4.71 4.25 0.61 0.138

MT 3.3 4.68 0.45 3.6 4.67 0.67 0.463

FT 7.37 5.45 0.52 5.94 4.48 0.65 0.167

DMFT 14.69 6.92 0.66 14.25 5.91 0.85 0.722

DT/DMFT 27.84 27.95 2.68 33.88 27.93 4.03 0.137

MT/DMFT 20.31 23.2 2.22 24.24 26.14 3.77 0.408

FT/DMFT 51.85 29.71 2.85 41.88 27.52 3.97 0.038


122

Table 35. Association between REALD-30 Level and the DMFT data

REALD-30 LEVEL

p value* High Marginal or Low



DT 3.4 4.26 0.55 4.79 4.78 0.48 0.053

MT 3.7 5.52 0.71 3.26 4.07 0.41 0.976

FT 7.73 5.5 0.71 6.34 4.98 0.5 0.121

DMFT 14.83 7.34 0.95 14.39 6.21 0.62 0.835

DT/DMFT 22.65 23.54 3.04 34.14 29.59 2.97 0.019

MT/DMFT 22.5 25.46 3.29 21.37 23.38 2.35 0.913

FT/DMFT 54.85 30.25 3.9 44.49 28.37 2.85 0.027


123

Table 36. Association between REALM Level and the DMFT data

REALM LEVEL

p value* Adequate Marginal or Low



DT 4.33 4.74 0.43 4.05 4.28 0.7 0.886

MT 3.28 4.79 0.43 3.92 4.19 0.69 0.076

FT 7.2 5.27 0.48 5.76 4.9 0.81 0.149

DMFT 14.8 6.75 0.61 13.73 6.28 1.03 0.438

DT/DMFT 29.94 28.65 2.59 29.35 25.87 4.25 0.914

MT/DMFT 19.94 23.78 2.15 27.91 24.53 4.03 0.034

FT/DMFT 50.12 29.71 2.69 42.74 28.14 4.63 0.144


124

Table 37. Prevalence of periodontal pockets by highest score (n=120)

Count %

Participants with all sites ≤3mm 8 6.7%

Participants with at least one site =4 mm 31 25.8%

Participants with at least one site=5 mm 28 23.3%

Participants with at least one site=6 mm 24 20.0%

Participants with at least one site >6 mm 29 24.2%

125

Table 38. Chi square analysis between oral health literacy level and the prevalence of the periodontal

pockets depths (cut-off point at 3mm)

Participants with all sites ≤3mm

Participants with at least one site

>3mm OR 95% CI

p value*

n % n % Lower Upper

CCOHLI Level

Adequate 5 7.9% 58 92.1% 1.494 0.34 6.561 0.722

Inadequate 3 5.5% 52 94.5%

OHLI Level

Adequate 6 7.8% 71 92.2% 1.521 0.292 7.919 1


REALD-30 Level

High 3 7.9% 35 92.1% 1.269 0.287 5.611 0.713



126

Table 39. Logistic regression model for CCOHLI Level (inadequate) (n=138)

Independent Variables Coefficient Odds ratio 95% CI of odds ratio

p value Lower Upper

Age -.014 .986 .951 1.022 .443

Gender (male) -.069 .933 .401 2.172 .872

Native language (other than English) -.056 .945 .347 2.574 .912

Time being in Canada (less than 10 years)

-.115 .891 .282 2.819 .844

Education level (less than college degree)

-.393 .675 .265 1.721 .410

Annual income (less than $40,000) -.342 .710 .257 1.962 .509

Last dental visit (more than 12 months or never)

-.602 .548 .215 1.393 .206

Reason for last dental visit (emergency)

-.097 .907 .376 2.192 .829

Attending regular check-up (no) .402 1.495 .491 4.554 .479

Frequency of brushing (once/day or never)

1.056 2.874 .950 8.694 .062

Flossing (no) 1.011 2.749 1.024 7.379 .045

Self-perceived oral health (fair or poor)

1.302 3.675 1.441 9.371 .006

Dental knowledge score -.012 .988 .967 1.009 .271

OHIP-14 prevalence score .212 1.236 .502 3.044 .645

Any untreated dental caries. 1.468 4.341 1.139 16.551 .032

Number of missing teeth .015 1.015 .899 1.147 .807

FT/DMFT (%) .004 1.004 .985 1.023 .709

Constant -1.205 .300 - - .393

-2 Log-likelihood = 151.795; Cox & Snell R2 = 0.239; Nagelkerke R2 = 0.320; Hosmer and Lemeshow chi-

squared test= 6.016, d.f. = 8, P = 0.645

127

Table 40. Logistic regression model for OHLI Level (marginal or inadequate) (n=135)


p value Lower Upper

Age .020 1.021 .975 1.069 .384

Gender (male) -.031 .970 .320 2.938 .957

Native language (other than English) 1.530 4.617 1.361 15.656 .014


1.380 3.973 .986 16.016 .052


.148 1.160 .346 3.883 .810

Annual income (less than $40,000) 1.457 4.292 .937 19.662 .061


-.448 .639 .204 1.998 .441


-.774 .461 .143 1.487 .195

Attending regular check-up (no) 1.771 5.874 1.217 28.347 .027


1.014 2.755 .713 10.643 .142

Flossing (no) -.981 .375 .098 1.438 .153


.754 2.126 .583 7.749 .253

Dental knowledge score -.065 .937 .907 .968 .000

OHIP-14 prevalence score -1.338 .262 .074 .925 .037

Any untreated dental caries. 2.095 8.123 1.361 48.497 .022

Number of missing teeth .145 1.156 .976 1.370 .094

FT/DMFT (%) .007 1.007 .983 1.033 .565

Constant -3.744 .024 - - .057


squared test = 8.538, d.f. = 8, P = 0.383

128

Table 41. Logistic regression model for REALD-30 Level (marginal or low) (n=137)


p value Lower Upper

Age -.020 .981 .947 1.016 .274

Gender (male) .085 1.089 .481 2.464 .838

Native language (other than English) .506 1.659 .628 4.385 .307


-.034 .966 .300 3.113 .954


.204 1.226 .484 3.104 .667

Annual income (less than $40,000) .168 1.183 .455 3.077 .730


-.942 .390 .154 .989 .047


-.173 .841 .347 2.040 .702

Attending regular check-up (no) .346 1.414 .480 4.161 .530


.246 1.278 .420 3.891 .665

Flossing (no) -.497 .608 .225 1.643 .327


.338 1.403 .579 3.396 .453

Dental knowledge score -.022 .978 .958 .998 .032

OHIP-14 prevalence score -.387 .679 .279 1.650 .393

Any untreated dental caries. .301 1.351 .439 4.159 .600

Number of missing teeth -.003 .997 .883 1.126 .963

FT/DMFT (%) -.012 .988 .970 1.006 .202

Constant 3.042 20.950 - - .021


squared test=6.187, d.f. = 8, P = 0.626

129

Table 42. Reliability test for Communicative and Critical Oral Health Literacy Instrument (CCOHLI)

(n=174)

No. of items Cronbach's Alpha

Communicative OHLI 5 0.813

Critical OHLI 4 0.845

CCOHLI 9 0.875

130

Table 43. Intra-class Correlation Coefficient (ICC) for Communicative and Critical Oral Health Literacy Instrument (CCOHLI) (n = 84)

ICC

Communicative OHLI 0.699

Critical OHLI 0.582

CCOHLI 0.741

131

Part 3:

Oral Health Literacy Screening Questions

The responses to the oral health literacy screening questions are presented in Table 44.

About 44% of the patients indicated that they never had any problems learning about dental

conditions. About half of the sample stated that they were confident filling out medical and

dental forms. The majority of patients (about 70%) indicated they could follow the instructions

on the label of a medication bottle and that they have never had someone helping them read

hospital literature.

Detecting inadequate and marginal oral health literacy, measured using OHLI

AUROCs for the four oral health literacy screening questions and their different

combinations are presented in Table 45. The AUROCs for all the questions were significantly

higher than the null value (0.5) as detected by the 95% confidence intervals (CI). The AUROC for

the individual screening questions ranged between 0.608 and 0.689, with Q2 “confident in filling

forms” performing better than the other questions. Combining the screening questions

increased the AUROCs for some of the combinations but this increase was not significant

because of the overlap in the 95%CI of the question combinations and the individual questions.

Detecting inadequate oral health literacy, measured using CCOHLI


combinations are presented in Table 46. The AUROC for only one question (Q1) was significantly

higher than the null value (0.5) as detected by the 95% CI. AUROCs for the screening questions

ranged between 0.497 and 0.607, with Q1 “learning problems” performing better than the other

questions. Combining the screening questions did not increase the AUROCs for any of the

question combinations in comparison to the individual questions.

Detecting low and marginal oral health literacy, measured using REALD-30


combinations are presented in Table 47. The AUROCs for only two questions (Q1 and Q2) were

significantly higher than the null value (0.5) as detected by the 95% CI. AUROCs for the screening

questions ranged between 0.586 and 0.657, with Q1 “learning problems” performing better

132

than the other questions. Combining the screening questions increased the AUROCs for some of

the combinations but this increase was not significant because of the overlap in the 95% CI of

the question combinations and the individual questions.

Deciding cut-off points for the screening questions

Sensitivities, specificities, and positive and negative likelihood ratios (LRs) with 95% CI for all

the oral health literacy screening questions for detecting limited health literacy at each

threshold based on different oral health literacy tests are shown in Tables 48-50. The cut-off

points were selected so that the sum of the sensitivity and specificity was maximized and

significant positive and negative LRs were achieved (95% CI not crossing the null value=1). The

cut-off points were selected for the questions with significant AUROCs only. The selected cut-off

points for each question are highlighted in Tables 48-50.

133

Results tables for

Part 3

Validation of Screening Questions for Limited Oral Health

Literacy

134

Table 44. Frequency of responses (%) to limited oral health literacy screening questions (n =177)

Oral health literacy screening questions % (n)

Always Often Sometimes Occasionally Never

How often do you have problem learning about your medical/dental condition because of difficulty understanding written information?

1.7 (3) 6.8 (12) 23.2 (41) 23.7 (42) 44.6 (79)

How confident are you filling out medical/dental forms by yourself?

52.0 (92) 19.2 (34) 12.4 (22) 9.0 (16) 7.3 (13)

How confident do you feel you are able to follow the instructions on the label of a medication bottle?

70.1 (124) 18.6 (33) 2.3 (4) 3.4 (6) 5.6 (10)

How often do you have someone (like family member, friend, hospital/clinic worker or caregiver) helps you read hospital material?

1.7 (3) 5.6 (10) 10.7 (19) 11.3 (20) 70.6 (125)

135

Table 45. Areas under the receiver operating characteristic curve and 95% CI for the oral health literacy

screening questions (using OHLI level)

Oral health literacy screening questions

OHLI level (Inadequate or Marginal) (n=168)

Area Under the Curve

(AUC)

95% CI

Lower Upper

Q1: How often do you have problem learning about your medical/dental condition because of difficulty understanding written information?

.678 .587 .768

Q2: How confident are you filling out medical/dental forms by yourself?

.689 .600 .777

Q3: How confident do you feel you are able to follow the instructions on the label of a medication bottle?

.608 .513 .702

Q4: How often do you have someone (like family member, friend, hospital/clinic worker or caregiver) helps you read hospital material?

.626 .530 .722

Questions 1 and 2 .735 .654 .817

Questions 1 and 3 .695 .609 .781

Questions 1 and 4 .711 .624 .798

Questions 2 and 3 .707 .620 .794

Questions 2 and 4 .722 .637 .808

Questions 3 and 4 .660 .568 .752

Questions 1, 2 and 3 .737 .657 .817

Questions 1, 2 and 4 .753 .674 .832

Questions 1, 3 and 4 .716 .632 .801

Questions 2, 3 and 4 .728 .644 .812

Questions 1, 2, 3 and 4 .749 .670 .828

136


screening questions (using CCOHLI)


CCOHLI level (Inadequate) (n=174)


(AUC)

95% CI

Lower Upper


.607

.523 .692


.536

.450 .623


.559

.473 .645


.496

.409 .582

Questions 1 and 2 .591 .506 .676

Questions 1 and 3 .604 .520 .689

Questions 1 and 4 .589 .504 .674

Questions 2 and 3 .571 .484 .657

Questions 2 and 4 .523 .435 .610

Questions 3 and 4 .536 .449 .622

Questions 1, 2 and 3 .601 .515 .686

Questions 1, 2 and 4 .576 .491 .662

Questions 1, 3 and 4 .582 .497 .668

Questions 2, 3 and 4 .550 .463 .636

Questions 1, 2, 3 and 4 .580 .495 .666

137


screening questions (using REALD-30)


REALD-30 level (Low or Marginal) (n=170)


(AUC)

95% CI

Lower Upper


.657

.574 .740


.653

.570 .736


.594

.508 .679


.586 .500 .672

Questions 1 and 2 .708 .627 .789

Questions 1 and 3 .686 .604 .769

Questions 1 and 4 .671 .587 .754

Questions 2 and 3 .683 .602 .764

Questions 2 and 4 .682 .600 .764

Questions 3 and 4 .630 .546 .714

Questions 1, 2 and 3 .715 .635 .796

Questions 1, 2 and 4 .714 .632 .795

Questions 1, 3 and 4 .689 .607 .772

Questions 2, 3 and 4 .695 .614 .775

Questions 1, 2, 3 and 4 .718 .638 .799

138

Table 48. Performance of oral health literacy screening questions for detecting inadequate or marginal oral health literacy using OHLI

Oral health literacy screening questions Sensitivity Specificity +LR 95% CI -LR 95% CI

OHLI

Q1: Problems in learning

≥1 100 0 1 1.0 - 1.0

>1 Never 71.7 53.04 1.53 1.2 - 2.0 0.53 0.3 - 0.8

>2 Occasionally 52.83 78.26 2.43 1.6 - 3.7 0.6 0.4 - 0.8

>3 Sometimes 16.98 95.65 3.91 1.4 - 11.1 0.87 0.8 - 1.0

>4 Often 3.77 100 0.96 0.9 - 1.0

>5 Always 0 100 1 1.0 - 1.0

Q2: Confidence in filling forms

≥1 100 0 1 1.0 - 1.0

>1 Always 69.81 62.61 1.87 1.4 - 2.5 0.48 0.3 - 0.7

>2 Often 49.06 80.87 2.56 1.6 - 4.1 0.63 0.5 - 0.8

>3 Sometimes 28.3 90.43 2.96 1.5 - 6.0 0.79 0.7 - 0.9

>4 Occasionally 11.32 94.78 2.17 0.7 - 6.4 0.94 0.8 - 1.0

>5 Never 0 100 1 1.0 - 1.0

Q3: Confidence in following instructions.

≥1 100 0 1 1.0 - 1.0

>1 Always 45.28 76.52 1.93 1.2 - 3.0 0.72 0.5 - 0.9

>2 Often 16.98 91.3 1.95 0.8 - 4.5 0.91 0.8 - 1.0

>3 Sometimes 11.32 92.17 1.45 0.5 - 3.9 0.96 0.9 - 1.1

>4 Occasionally 7.55 94.78 1.45 0.4 - 4.9 0.98 0.9 - 1.1

>5 Never 0 100 1 1.0 - 1.0

Q4: Requiring help when reading materials.

≥1 100 0 1 1.0 - 1.0

>1 Never 43.4 78.26 2 1.3 - 3.2 0.72 0.6 - 0.9

>2 Occasionally 32.08 88.7 2.84 1.5 - 5.4 0.77 0.6 - 0.9

>3 Sometimes 16.98 98.26 9.76 2.2 - 43.6 0.84 0.7 - 1.0

>4 Often 3.77 100 0.96 0.9 - 1.0

>5 Always 0 100 1 1.0 - 1.0

139

Table 49. Performance of oral health literacy screening questions for detecting inadequate oral health literacy using CCOHLI


CCOHLI


≥1 100 0 1 1.0 - 1.0

>1 Never 65.38 54.17 1.43 1.1 - 1.9 0.64 0.4 - 0.9

>2 Occasionally 39.74 76.04 1.66 1.1 - 2.6 0.79 0.6 - 1.0

>3 Sometimes 8.97 92.71 1.23 0.5 - 3.4 0.98 0.9 - 1.1

>4 Often 2.56 98.96 2.46 0.2 - 26.6 0.98 0.9 - 1.0

>5 Always 0 100 1 1.0 - 1.0


≥1 100 0 1 1.0 - 1.0

>1 Always 50 54.17 1.09 0.8 - 1.5 0.92 0.7 - 1.2

>2 Often 34.62 77.08 1.51 0.9 - 2.4 0.85 0.7 - 1.0

>3 Sometimes 19.23 85.42 1.32 0.7 - 2.6 0.95 0.8 - 1.1

>4 Occasionally 6.41 91.67 0.77 0.3 - 2.3 1.02 0.9 - 1.1

>5 Never 0 100 1 1.0 - 1.0


≥1 100 0 1 1.0 - 1.0

>1 Always 37.18 75 1.49 0.9 - 2.3 0.84 0.7 - 1.0

>2 Often 14.1 90.62 1.5 0.7 - 3.4 0.95 0.8 - 1.1

>3 Sometimes 10.26 91.67 1.23 0.5 - 3.1 0.98 0.9 - 1.1

>4 Occasionally 5.13 93.75 0.82 0.2 - 2.8 1.01 0.9 - 1.1

>5 Never 0 100 1 1.0 - 1.0


≥1 0 100 1 1.0 - 1.0

>1 Never 71.79 30.21 1.03 0.8 - 1.2 0.93 0.6 - 1.5

>2 Occasionally 80.77 16.67 0.97 0.8 - 1.1 1.15 0.6 - 2.2

>3 Sometimes 91.03 6.25 0.97 0.9 - 1.1 1.44 0.5 - 4.1

>4 Often 100 3.12 1.03 1.0 - 1.1 0

>5 Always 100 0 1 1.0 - 1.0

140

Table 50. Performance of oral health literacy screening questions for detecting low or marginal oral health literacy using REALD-30


REALD-30


≥1 100 0 1 1.0 - 1.0

>1 Never 64.15 60 1.6 1.2 - 2.2 0.6 0.4 - 0.8

>2 Occasionally 43.4 86.15 3.13 1.6 - 6.0 0.66 0.5 - 0.8

>3 Sometimes 10.38 93.85 1.69 0.6 - 5.1 0.95 0.9 - 1.0

>4 Often 1.89 98.46 1.23 0.1 - 13.3 1 1.0 - 1.0

>5 Always 0 100 1 1.0 - 1.0


≥1 100 0 1 1.0 - 1.0

>1 Always 57.55 69.23 1.87 1.3 - 2.8 0.61 0.5 - 0.8

>2 Often 37.74 86.15 2.73 1.4 - 5.2 0.72 0.6 - 0.9

>3 Sometimes 21.7 93.85 3.53 1.3 - 9.7 0.83 0.7 - 0.9

>4 Occasionally 8.49 95.38 1.84 0.5 - 6.5 0.96 0.9 - 1.0

>5 Never 0 100 1 1.0 - 1.0


≥1 100 0 1 1.0 - 1.0

>1 Always 36.79 81.54 1.99 1.1 - 3.5 0.78 0.6 - 0.9

>2 Often 14.15 93.85 2.3 0.8 - 6.6 0.91 0.8 - 1.0

>3 Sometimes 11.32 95.38 2.45 0.7 - 8.4 0.93 0.9 - 1.0

>4 Occasionally 7.55 96.92 2.45 0.5 - 11.2 0.95 0.9 - 1.0

>5 Never 0 100 1 1.0 - 1.0


≥1 100 0 1 1.0 - 1.0

>1 Never 34.91 81.54 1.89 1.1 - 3.4 0.8 0.7 - 1.0

>2 Occasionally 22.64 89.23 2.1 1.0 - 4.6 0.87 0.8 - 1.0

>3 Sometimes 9.43 96.92 3.07 0.7 - 13.6 0.93 0.9 - 1.0

>4 Often 1.89 100 0.98 1.0 - 1.0

>5 Always 0 100 1 1.0 - 1.0

141

Part 4:

Interpersonal Processes of Care Questionnaire (IPC)

The distributions of responses to individual IPC items are given in Table 51. Overall, patients’

ratings of their previous communication experience with dentists before attending the Faculty

of Dentistry Clinics were positive, with IPC domain score means lying in the favorable half of the

Likert scale, except for the domain of the decision making around desire and ability to comply

with recommendations. The domains with the best communication ratings were general clarity

(mean=3.97), explanation of the condition score (mean=2.14) and elicitation and responsiveness

score (mean=2.18). The domain of worst performance was decision making around desire and

ability to comply with recommendations (mean=3.34). Data on IPC domains scores are

summarized in Table 52.

Overall, participants reported a favorable communication experience for all the IPC

domains, except the empowerment and decision-making domains (Table 53). The percentage of

participants who reported poor communication with their dentist ranged between 12.7 and

29.5%, except for the empowerment and decision-making in which the percentages of poor

communication were about 43 and 53%, respectively.

Association between IPC domains and socio-demographics, dental attendance, oral


Bivariate associations between different predictors and the IPC domains are presented in

Tables 54-67 and summarized in Table 68. Associations were evaluated using the domain scores

and level (poor or good). Bivariate analyses revealed that few predictors were significantly

associated with some of the IPC domain scores. Self-perceived oral health status was

significantly associated with the following domains: elicitation and responsiveness, explanation

of process of care and explanation of self-care. Favorable scores were reported for participants

who reported excellent, very good or good oral health status compared to those who reported

fair or poor oral health status. Last dental visit and reason of dental visit were associated with

general clarity and elicitation and responsiveness, respectively. Favorable scores were reported

for participants who reported that their last dental visit was more than 12 months ago or

emergency as a reason for their last visit. In addition, native language was significantly

associated with the decision-making domain score, with favorable scores for participants who

142

reported a language other than English as their native language.

Different associations emerged when domain level was used as an outcome. Again, self-

perceived oral health status was associated with the following domains: explanation of the

condition, explanation of process of care and explanation of self-care, with a higher percentage

of participants who reported excellent, very good or good oral health status reporting poor

communication with their dentist than those who reported fair or poor oral health status. In

addition, reason for last dental visit, annual income and frequency of tooth brushing were

associated with general clarity, elicitation and responsiveness or explanation of self-care,

respectively. Higher percentages of participants who reported reason for dental visit other than

emergency, lower annual income or lower frequency of tooth brushing reported poor

communication with their dentist than those who reported emergency as a reason for their last

dental visit, higher annual income or higher frequency of tooth brushing.

Correlation between the IPC domains and different dental knowledge, health literacy

and oral health literacy tests

Non-parametric bivariate correlations between CCOHLI, OHLI, REALM, REALD-30, oral

health knowledge test and IPC scores are summarized in Table 69.

o CCOHLI: Spearman’s correlation revealed weak negative correlations between

communicative oral health literacy score and all the IPC domains except the general

clarity. On the other hand, significant weak negative correlations were observed

between critical oral health literacy score and only two of the domains (elicitation and

responsiveness and explanation of self-care). Similarly, significant weak negative

correlations were identified between the CCOHLI score and the four of the IPC

domains: elicitation and responsiveness, explanation of the condition, explanation of

self-care, and empowerment domains.

o OHLI: No significant association was observed between the scores of the reading

section and any of the IPC domains. In contrast, weak negative correlations were

observed between the numeracy section and total OHLI scores and two of the domains

(elicitation and responsiveness, and empowerment). Furthermore, a significant weak

negative correlation was found between the numeracy section scores and explanation

of self-care domain.

143

o REALD-30: No significant association was observed between REALD-30 score and any of

the IPC domains.

o REALM: A significant weak positive correlation was observed between general clarity

and REALM scores. In contrast, a significant weak negative correlation was observed

between the elicitation and responsiveness domain and REALM scores.

o Oral health knowledge test: No significant association was observed between oral

health knowledge test score and any of the IPC domains.

Association between IPC domains and different dental knowledge, health literacy and

oral health literacy tests

Bivariate associations between the IPC domain levels (poor or good) and the scores for

different tests are presented in Tables 70-76 and summarized in Table 84.

o CCOHLI: Bivariate analyses revealed significantly lower communicative oral health

literacy scores, on average, among the participants who reported poor communication

with their dentists in comparison to those who reported good communication for all

the domains except general clarity and explanation of the care process. In contrast,

critical oral health literacy was significantly associated with only one domain (elicitation

and responsiveness), with lower average scores for participants who reported poor

communication with their dentists than those who reported good communication.

Further, the combined score (CCOHLI score) was significantly lower among the

participants who reported poor communication with their dentist in comparison to

those who reported good communication for the following domains: elicitation and

responsiveness, explanation of the condition and explanation of self-care.

o OHLI: Bivariate analyses revealed significant associations between the OHLI and its

numeracy section scores and explanation of the condition and empowerment domains,

with significantly lower numeracy and total OHLI scores, on average, among the

participants who reported poor communication with their dentists in comparison to

those who reported good communication. In addition to these two domains, numeracy

section scores were significantly associated with a third domain (elicitation and

responsiveness), with lower average scores for participants who reported poor

communication with their dentists in comparison to those who reported good

144

communication. In contrast, no significant association was identified between the

reading section scores and any of the domains.

o REALD-30, REALM and dental knowledge test: No significant association was observed

between any of the test scores and any of the IPC domains.

Association between IPC domains and oral health literacy level

Bivariate analyses that compared IPC domains by participants’ level of oral health literacy

are presented in Tables 77-83 and summarized in Table 84. No significant association was

identified between oral health literacy level (measured using OHLI) and any of the IPC domains.

On the other hand, participants with inadequate communicative and critical oral health literacy

level had poorer quality of communication with their dentist for all the domains except general

clarity. Similarly, participants who had a low or marginal oral health literacy level (measured

using the REALD-30) had significantly worse rating of their quality of communication with their

dentists in the general clarity domain.

Multivariate analyses to assess the association between different predictors, including

oral health literacy, and IPC domains

Multicollinearity diagnostics did not reveal any sign of severe interactions among the

predictors with VIF values <10 and tolerance values >0.4. Logistic regression models were

developed to predict the quality of communication (dichotomized to poor and good) from a set

of predictors, including oral health literacy. Four models were developed for each IPC domain. In

the first three models, one of the three oral health literacy instruments (OHLI, CCOHLI OR

REALD-30) was included as a predictor, while all the oral health literacy instruments were

included in the fourth model (Tables 85-91) and results were summarized in Table 92. This

approach was followed to avoid the homoscedasticity due to moderate correlations between

some of the test scores.

The findings of the models can be summarized as follows:

o OHLI was not associated with any of the IPC domains after adjusting for other predictors.

o While REALD-30 was a significant predictor in only one of the logistic regression models

(which includes all the instruments) for the explanation of self-care domain.

o CCOHLI score remained significantly associated with quality of patient-dentist

145

communication across three of the seven IPC domains (elicitation and responsiveness,

explanation of self-care and decision-making), with about 52 to 56% decrease in the

likelihood of reporting poor communication in the above domains with each unit increase

in the CCOHLI score.

o Dental knowledge test score remained as a significant predictor in some of the logistic

regression models for three of the IPC domains (explanation of process of care,

empowerment and decision-making), with about 2 to 4% decrease in the likelihood of

reporting poor communication in the above domains with each unit increase in the dental

knowledge test score.

o Self-perceived oral health status remained as a significant predictor in some of the logistic

regression models for the two of the domains (explanation of the condition and

explanation of process of care), with about 3.4 to 5.1 increase in the likelihood of

reporting poor communication in the above domains among the participants who

reported fair or poor oral health status.

o Annual income was significant predictor in one of the logistic regression models for the

general clarity domain.

o The time and reason for last dental visit were significant predictors in all of the logistic

regression models for the general clarity domain.

Pattern of communication and oral hygiene barriers

The responses to the questions about pattern of communication at the undergraduate

clinics and barriers encountered by the patient are summarized in Table 93. Only 61% of the

participants reported that they have received information regarding their dental problems. This

information was delivered verbally to 99% of the participants who reported receiving it. Only

one patient received written information and no electronic information was delivered to any of

the participants. The vast majority of participants (92%) stated that they understood the

delivered information. Only 7 participants reported that they did not understand the delivered

information because: it was complicated (4 patients), dentist did not spend enough time to

clarify it (2 patients), and he/she was embarrassed to ask for clarification (1 patient). Most of the

patients (88%) reported that they were given enough time to ask questions and that their

questions were answered to their satisfaction about 95% of the time. About half of the sample

146

received oral hygiene instructions and indicated that they are planning to follow these

instructions.

The responses to the pattern of communication and oral hygiene barrier questions were

analyzed among the subgroups divided by the undergraduate student year (3rd or 4th year)

(Table 94). Significantly higher percentages of the 3rd year students failed to provide their

patients with information about their dental problems and how to prevent them during the oral

diagnosis in comparison to 4th year students (42.5% vs. 22.2%). Only 1 fourth year student

(3.8%) did not provide his patient with enough time to ask questions compared to 17 (14.7%)

third year students, however; this difference did not reach statistical significance (p>0.05). Only

half of the 3rd year students provided their patients with oral hygiene instructions compared to

77% of the 4th year students (p<0.001).

147

Results tables for

Part 4

Oral Health Literacy and Dentist-Patient Communication

148

Table 51. Frequency of responses to Interpersonal Processes of Care in Diverse Populations

Questionnaire (IPC)

Subscale* Questions % (n)

Always Often Sometimes Rarely Never

General clarity (n =175)

How often did your dentist use medical/dental words that you did not understand?

1.1 (2) 8.6 (15) 27.4 (48)

38.3 (67) 24.6 (43)

9.7 (17) 62.9 (110)

How often did you have trouble understanding your dentist because he/she spoke too fast?

0.6 (1) 4.6 (8) 18.3 (32)

29.1 (51) 47.4 (83)

5.2 (9) 76.5 (134)

Elicitation of and

responsiveness to patient problems,

concerns and expectations

(n =175)

How often did your dentist give you enough time to say what you thought was important?

31.4 (55) 32.6 (57) 20.0 (35)

10.3 (18) 5.7 (10)

64.0 (112) 16.0 (28)

How often did your dentist listen carefully to what you had to say?

37.1 (65) 33.7 (59)

17.1 (30)

6.9 (12) 5.1 (9)

70.8 (124) 12 (21)

Explanations of condition (n =173)

How often did your dentist give you enough information about your oral health problems?

34.1 (59) 33.5 (58) 18.5 (32)

9.8 (17) 4.0 (7)

67.6 (117) 13.8 (24)

How often did your dentist make sure you understood your oral health problems?

36.4 (63) 31.2 (54) 19.1 (33)

9.8 (17) 3.5 (6)

67.6 (117) 13.3 (23)

Explanations of processes of

care (n =173)

How often did your dentist explain why the dental procedure was being done?

45.1 (78) 24.9 (43) 18.5 (32)

8.1 (14) 3.5 (6)

70.0 (121) 11.6 (20)

How often did your dentist explain how the dental procedure is done?

38.7 (67) 20.8 (36) 19.1 (33)

11.6 (20) 9.8 (17)

59.5 (103) 21.4 (37)

How often did you feel confused about what was going on with your dental care because your dentist did not explain things well?

1.7 (3) 8.7 (15)

22.5 (39)

30.6 (53) 36.4 (63)

10.4 (18) 67.0 (116)

Explanations of self-care (n =173)

How often did your dentist tell you what you could do to take care of your oral hygiene at home?

38.2 (66) 31.2 (54) 19.7 (34)

6.9 (12) 4.0 (7)

69.4 (120) 10.9 (19)

How often did your dentist tell you how to pay attention to your symptoms and when to call him/her?

23.0 (41) 18.5 (32) 24.9 (43)

16.8 (29) 16.2 (28)

41.5 (73) 33.0 (57)

How often did your dentist explain clearly or demonstrate to you how to perform oral hygiene procedures?

26.6 (46) 24.3 (42)

28.3 (49)

8.7 (15) 12.1 (21)

50.9 (88) 20.8 (36)


149

How often did your dentist give you written instructions about how to perform oral hygiene procedures?

10.4 (18) 7.5 (13) 22.0 (38)

20.2 (35) 39.9 (69)

17.9 (31) 60.1 (104)

Empowerment (n =174)

How often did your dentist make you feel that performing your oral hygiene practices would make a difference in your oral health?

25.3 (44) 29.3 (51)

21.3 (37)

12.6 (22) 11.5 (20)

54.6 (95) 24.1 (42)

How often did your dentist make you feel that your everyday activities such as your diet would make a difference in your oral health?

10.9 (19) 15.5 (27)

22.4 (39)

23.0 (40) 28.2 (49)

26.4 (46) 51.2 (89)

Decision-making around

desire and ability to comply (n =174)

How often did your dentist ask if you might have any problems doing the recommended oral hygiene measures?

10.3 (18) 12.6 (22) 20.7 (36)

26.4 (46) 29.9 (52)

22.9 (40) 56.3 (98)

How often did your dentist understand the kinds of problems you might have in doing the recommended oral hygiene measures?

14.4 (25) 20.1 (35)

26.4 (46)

13.2 (23) 25.9 (45)

34.5 (60) 39.1 (68)

*The range of all the scores is 1 to 5. On the domain of general clarity, higher scores indicated more

favorable responses. On other domains, lower scores indicate more favorable response

150

Table 52. Mean scores for Interpersonal Processes of Care in Diverse Populations Questionnaire (IPC)

subscales

Dimension* Mean ( ± SD)

IPC general clarity score 3.97 (0.85)

IPC elicitation and responsiveness score 2.18 (1.04)

IPC explanation of the condition score 2.14 (1.07)

IPC explanation of process of care score 2.75 (0.69)

IPC explanation of self-care score 2.80 (1.03)

IPC empowerment score 2.99 (1.18)

IPC decision-making score 3.34 (1.25)

*The range of all the scores is 1 to 5. On the domain of general clarity, higher scores indicated more

favorable responses. On other domains, lower scores indicate more favorable responses.

151

Table 53. Percentage of participants reporting poor and good Interpersonal Processes of Care (IPC)

Dimension* Poor Good

n % n %

IPC general clarity score* 40 22.9 135 77.1

IPC elicitation and responsiveness score** 28 16 147 84

IPC explanation of the condition score** 28 16.2 145 83.8

IPC explanation of process of care score** 22 12.7 151 87.3

IPC explanation of self-care score** 51 29.5 122 70.5

IPC empowerment score** 74 42.5 100 57.5

IPC decision-making score** 92 52.9 82 47.1

* Negative attributes: mean sub-scale scores of 1–3 on the Likert scale corresponding to

always/often/sometimes, were categorized as poor IPC, while mean sub-scale scores of 4–5 on the Likert

scale, corresponding to never/rarely, were categorized as good IPC.

** Positive attributes: mean sub-scale scores of 4–5 on the Likert scale, corresponding to never/rarely,

were categorized as poor IPC, while mean sub-scale scores of 1–3 on the Likert scale, corresponding to

always/often/sometimes, were categorized as good IPC.

152

Table 54. Association between IPC general clarity score and some predictors

IPC general clarity score

Mean SD Standard


Age

18-24 years old 3.7 1.03 0.33 4

0.186** 25-44 years old 3.88 0.83 0.1 4

45-64 years old 4.01 0.88 0.1 4

+65 years old 4.32 0.63 0.14 4

Gender

Females 4.04 0.84 0.09 4 0.367

Males 3.92 0.87 0.09 4

Language

English 4.03 0.84 0.08 4 0.190

Other 3.84 0.88 0.13 4


10 years or more 4.01 0.85 0.07 4 0.323

Less than 10 years 3.85 0.86 0.15 4

Education level



Annual income

$40,000 or more 3.97 0.88 0.13 4 0.932

Less than $40,000 3.96 0.85 0.08 4

Last dental visit




Others 4.07 0.81 0.08 4 0.072

Emergency 3.82 0.9 0.11 4


Yes 3.96 0.85 0.11 4 0.773

No 3.99 0.86 0.08 4


Twice or more 3.96 0.83 0.07 4 0.272

Once or never 4.09 0.94 0.16 4.5


Yes or sometimes 3.94 0.84 0.07 4 0.188

No 4.11 0.89 0.14 4.5


Excellent, very good or good 4.11 0.74 0.08 4 0.175

Fair or poor 3.9 0.89 0.1 4



153

Table 55. Association between IPC elicitation and responsiveness score and some predictors

IPC elicitation and responsiveness score

Mean SD Standard


Age

18-24 years old 2.15 0.78 0.25 2

0.770** 25-44 years old 2.22 1.03 0.12 2

45-64 years old 2.12 1.1 0.13 2

+65 years old 2.29 0.95 0.22 2.5

Gender

Females 2.13 1.01 0.11 2 0.588

Males 2.21 1.06 0.11 2

Language

English 2.13 1.05 0.09 2 0.429

Other 2.23 0.95 0.14 2


10 years or more 2.14 1 0.08 2 0.736

Less than 10 years 2.24 1.1 0.19 2

Education level

College degree or more 2.15 1 0.1 2 0.812


Annual income

$40,000 or more 1.96 0.84 0.12 2 0.171

Less than $40,000 2.25 1.08 0.1 2

Last dental visit




Others 2.03 0.98 0.09 2 0.025

Emergency 2.4 1.1 0.14 2.5


Yes 2.05 1 0.13 2 0.298

No 2.23 1.05 0.1 2


Twice or more 2.14 1.02 0.09 2 0.522

Once or never 2.29 1.12 0.19 2


Yes or sometimes 2.19 1.03 0.09 2 0.508

No 2.1 1.07 0.17 2


Excellent, very good or good 2 1.03 0.12 2 0.025

Fair or poor 2.34 1.06 0.11 2.5



154

Table 56. Association between IPC explanation of the condition score and some predictors

IPC explanation of the condition score

Mean SD Standard


Age

18-24 years old 2.35 0.71 0.22 2.25

0.739** 25-44 years old 2.12 0.95 0.11 2

45-64 years old 2.15 1.17 0.13 2

+65 years old 2.11 1.24 0.29 1.5

Gender

Females 2.08 1.02 0.12 2 0.545

Males 2.2 1.11 0.11 2

Language

English 2.17 1.11 0.1 2 0.741

Other 2.07 0.97 0.14 2


10 years or more 2.15 1.1 0.09 2 0.930

Less than 10 years 2.12 0.95 0.17 2

Education level



Annual income

$40,000 or more 2.07 0.99 0.15 2 0.632

Less than $40,000 2.19 1.1 0.1 2

Last dental visit


More than 12 months or never 2.04 1 0.11 2


Others 2.03 0.99 0.1 2 0.136

Emergency 2.32 1.18 0.15 2.25


Yes 2.09 1.1 0.15 2 0.478

No 2.18 1.05 0.1 2


Twice or more 2.08 1.03 0.09 2 0.156

Once or never 2.41 1.19 0.21 2.25


Yes or sometimes 2.12 1.07 0.09 2 0.569

No 2.21 1.06 0.17 2



Fair or poor 2.28 1.13 0.12 2



155

Table 57. Association between IPC explanation of process of care score and some predictors

IPC explanation of process of care score

Mean SD Standard


Age

18-24 years old 3.07 0.56 0.18 3

0.207** 25-44 years old 2.76 0.73 0.09 2.67

45-64 years old 2.67 0.67 0.08 2.33

+65 years old 2.84 0.7 0.16 2.33

Gender

Females 2.81 0.75 0.08 2.67 0.325

Males 2.7 0.64 0.07 2.67

Language

English 2.76 0.68 0.06 2.67 0.827

Other 2.75 0.72 0.1 2.5


10 years or more 2.74 0.7 0.06 2.67 0.501

Less than 10 years 2.82 0.64 0.11 2.67

Education level



Annual income

$40,000 or more 2.64 0.72 0.11 2.67 0.306

Less than $40,000 2.8 0.69 0.06 2.67

Last dental visit




Others 2.69 0.66 0.06 2.67 0.493

Emergency 2.78 0.73 0.09 2.67


Yes 2.63 0.55 0.07 2.5 0.277

No 2.78 0.75 0.07 2.67


Twice or more 2.7 0.64 0.05 2.67 0.242

Once or never 2.95 0.87 0.15 2.67


Yes or sometimes 2.73 0.66 0.06 2.67 0.966

No 2.78 0.8 0.12 2.67



Fair or poor 2.89 0.74 0.08 2.67



156

Table 58. Association between IPC explanation of self-care score and some predictors

IPC explanation of self-care score

Mean SD Standard


Age

18-24 years old 3.25 0.54 0.17 3.38

0.276** 25-44 years old 2.83 1.07 0.13 3

45-64 years old 2.7 1.04 0.12 2.63

+65 years old 2.82 1 0.23 3

Gender

Females 2.77 1.11 0.13 2.75 0.606

Males 2.82 0.97 0.1 2.75

Language

English 2.81 1.03 0.09 2.75 0.951

Other 2.81 1.03 0.15 2.88


10 years or more 2.76 1.01 0.09 2.75 0.196

Less than 10 years 3.03 1.09 0.19 3

Education level



Annual income

$40,000 or more 2.62 0.92 0.13 2.75 0.152

Less than $40,000 2.87 1.07 0.1 3

Last dental visit




Others 2.73 0.99 0.1 2.75 0.416

Emergency 2.89 1.11 0.14 3


Yes 2.69 0.94 0.12 2.75 0.360

No 2.85 1.08 0.1 3


Twice or more 2.72 0.98 0.08 2.75 0.072

Once or never 3.12 1.14 0.2 3.25


Yes or sometimes 2.76 1.04 0.09 2.75 0.408

No 2.9 0.99 0.15 3



Fair or poor 2.99 1.02 0.11 3



157

Table 59. Association between IPC empowerment score and some predictors

IPC empowerment score

Mean SD Standard


Age

18-24 years old 3.55 0.76 0.24 3.75

0.110** 25-44 years old 2.91 1.17 0.14 3

45-64 years old 2.89 1.26 0.14 2.5

+65 years old 3.35 0.92 0.21 3.5

Gender

Females 2.92 1.16 0.13 2.5 0.380

Males 3.05 1.19 0.12 3

Language

English 3.01 1.2 0.11 3 0.948

Other 3 1.09 0.16 3


10 years or more 2.98 1.15 0.1 3 0.541

Less than 10 years 3.12 1.24 0.22 3

Education level



Annual income

$40,000 or more 2.82 1.06 0.15 2.5 0.249

Less than $40,000 3.04 1.22 0.11 3

Last dental visit




Others 2.91 1.11 0.11 3 0.245

Emergency 3.1 1.3 0.17 3.25


Yes 2.97 1.24 0.16 3 0.921

No 3 1.15 0.11 3


Twice or more 2.93 1.17 0.1 3 0.178

Once or never 3.25 1.16 0.21 3.25


Yes or sometimes 2.91 1.22 0.11 3 0.118

No 3.23 1.01 0.16 3



Fair or poor 3.11 1.13 0.12 3



158

Table 60. Association between IPC decision-making score and some predictors

IPC decision-making score

Mean SD Standard


Age

18-24 years old 3.95 1.07 0.34 4

0.096** 25-44 years old 3.18 1.25 0.15 3

45-64 years old 3.29 1.26 0.14 3.25

+65 years old 3.82 1.15 0.26 3.75

Gender

Females 3.18 1.2 0.13 3 0.080

Males 3.48 1.28 0.13 3.5

Language

English 3.48 1.27 0.11 3.5 0.042

Other 3.06 1.09 0.16 3


10 years or more 3.39 1.25 0.11 3.5 0.651

Less than 10 years 3.27 1.18 0.21 3.5

Education level



Annual income

$40,000 or more 3.2 1.26 0.18 3.5 0.346

Less than $40,000 3.41 1.25 0.11 3.5

Last dental visit




Others 3.36 1.18 0.11 3.5 0.940

Emergency 3.3 1.37 0.17 3


Yes 3.33 1.22 0.16 3.5 0.960

No 3.34 1.26 0.12 3.5


Twice or more 3.28 1.23 0.1 3.5 0.111

Once or never 3.66 1.29 0.23 3.75


Yes or sometimes 3.29 1.28 0.11 3.5 0.304

No 3.52 1.15 0.18 3.5



Fair or poor 3.43 1.21 0.13 3.5



159

Table 61. Chi square analysis between IPC general clarity score and some predictors

IPC general clarity

Poor Good OR

95% CI p value

n % n % Lower Upper

Age

18-24 years old 3 30.0% 7 70.0% 0.887 0.208 3.788 1 *

25-44 years old 19 27.5% 50 72.5% Ref. - - -

45-64 years old 17 22.1% 60 77.9% 0.746 0.351 1.585 0.445

+65 years old 1 5.3% 18 94.7% 0.150 0.018 1.172 0.061*

Gender

Females 17 21.5% 62 78.5% .1.149 .564 2.343 0.702

Males 23 24.0% 73 76.0%

Language

English 26 20.8% 99 79.2% 1.414 .655 3.052 0.376

Other 13 27.1% 35 72.9%


10 years or more 31 22.3% 108 77.7% 1.072 .441 2.603 0.878

Less than 10 years 8 23.5% 26 76.5%

Education level



Annual income

$40,000 or more 12 25.5% 35 74.5% .860 .394 1.874 0.704

Less than $40,000 28 22.8% 95 77.2%

Last dental visit




Others 17 15.7% 91 84.3% 2.742 1.311 5.736 0.006

Emergency 21 33.9% 41 66.1%


Yes 14 24.1% 44 75.9% .893 .423 1.886 0.766

No 25 22.1% 88 77.9%


Twice or more 31 22.1% 109 77.9% 1.125 .462 2.741 0.795

Once or never 8 24.2% 25 75.8%


Yes or sometimes 31 23.7% 100 76.3% .759 .318 1.810 0.533

No 8 19.0% 34 81.0%



Fair or poor 22 25.9% 63 74.1%


160

Table 62. Chi square analysis between IPC elicitation and responsiveness and some predictors

IPC elicitation and responsiveness

Poor Good OR

95% CI p value

n % n % Lower Upper

Age

18-24 years old 1 10.0% 9 90.0% 0.528 0.061 4.566 1 *

25-44 years old 12 17.4% 57 82.6% Ref. - - -

45-64 years old 13 16.9% 64 83.1% 0.965 0.407 2.283 0.935

+65 years old 2 10.5% 17 89.5% 0.559 0.114 2.747 0.725*

Gender

Females 12 15.2% 67 84.8% 1.117 .494 2.525 0.791

Males 16 16.7% 80 83.3%

Language

English 20 16.0% 105 84.0% .896 .352 2.279 0.818

Other 7 14.6% 41 85.4%


10 years or more 21 15.1% 118 84.9% 1.204 .445 3.261 0.715

Less than 10 years 6 17.6% 28 82.4%

Education level



Annual income

$40,000 or more 3 6.4% 44 93.6% 3.373 .962 11.825 0.046

Less than $40,000 23 18.7% 100 81.3%

Last dental visit




Others 14 13.0% 94 87.0% 1.781 .777 4.086 0.169

Emergency 13 21.0% 49 79.0%


Yes 7 12.1% 51 87.9% 1.567 .621 3.955 0.339

No 20 17.7% 93 82.3%


Twice or more 20 14.30% 120 85.70% 1.615 .619 4.217 0.324

Once or never 7 21.20% 26 78.80%


Yes or sometimes 20 15.30% 111 84.70% 1.110 .433 2.844 0.828

No 7 16.70% 35 83.30%



Fair or poor 16 18.80% 69 81.20% *p value obtained from Fisher exact test

161

Table 63. Chi square analysis between IPC explanation of the condition level and some predictors

IPC explanation of the condition

Poor Good OR

95% CI p value

n % n % Lower Upper

Age

18-24 years old 1 10.0% 9 90.0% 0.833 0.093 7.463 1*

25-44 years old 8 11.8% 60 88.2% Ref. - - -

45-64 years old 16 21.1% 60 78.9% 2.000 0.796 5.025 0.135

+65 years old 3 15.8% 16 84.2% 1.406 0.334 5.917 0.699*

Gender

Females 11 14.1% 67 85.9% 1.328 .581 3.031 0.500

Males 17 17.9% 78 82.1%

Language

English 22 17.9% 101 82.1% .656 .248 1.733 0.392

Other 6 12.5% 42 87.5%


10 years or more 24 17.4% 114 82.6% .655 .211 2.037 0.462

Less than 10 years 4 12.1% 29 87.9%

Education level



Annual income

$40,000 or more 5 10.6% 42 89.4% 1.867 .662 5.260 0.232

Less than $40,000 22 18.2% 99 81.8%

Last dental visit




Others 13 12.3% 93 87.7% 2.087 .909 4.792 0.079

Emergency 14 22.6% 48 77.4%


Yes 8 13.8% 50 86.2% 1.291 .527 3.159 0.576

No 19 17.1% 92 82.9%


Twice or more 19 13.7% 120 86.3% 2.105 .826 5.363 0.113

Once or never 8 25.0% 24 75.0%


Yes or sometimes 20 15.4% 110 84.6% 1.132 .441 2.907 0.796

No 7 17.1% 34 82.9%


Excellent, very good or good 6 7.5% 74 92.5% 3.915 1.481 10.351 0.004


162

Table 64. Chi square analysis between IPC explanation of process of care and some predictors

IPC explanation of process of care

Poor Good OR

95% CI p value

n % n % Lower Upper

Age

18-24 years old 3 30.0% 7 70.0% 2.809 0.612 12.821 0.178 *

25-44 years old 9 13.2% 59 86.8% Ref. - - -

45-64 years old 7 9.2% 69 90.8% 0.665 0.233 1.894 0.443

+65 years old 3 15.8% 16 84.2% 1.229 0.298 5.076 0.720*

Gender

Females 12 15.4% 66 84.6% .647 .263 1.589 0.340

Males 10 10.5% 85 89.5%

Language

English 16 13.0% 107 87.0% .955 .350 2.607 0.929

Other 6 12.5% 42 87.5%


10 years or more 18 13.0% 120 87.0% .920 .289 2.924 0.887

Less than 10 years 4 12.1% 29 87.9%

Education level



Annual income

$40,000 or more 6 12.8% 41 87.2% 1.041 .381 2.845 0.937

Less than $40,000 16 13.2% 105 86.8%

Last dental visit




Others 9 8.5% 97 91.5% 2.073 .792 5.421 0.131

Emergency 10 16.1% 52 83.9%


Yes 5 8.6% 53 91.4% 1.656 .570 4.811 0.350

No 15 13.5% 96 86.5%


Twice or more 15 10.8% 124 89.2% 2.315 .856 6.259 0.138*

Once or never 7 21.9% 25 78.1%


Yes or sometimes 16 12.3% 114 87.7% 1.221 .444 3.360 0.698

No 6 14.6% 35 85.4%




163

Table 65. Chi square analysis between IPC explanation of self-care and some predictors

IPC explanation of self-care

Poor Good OR

95% CI p value

n % n % Lower Upper

Age

18-24 years old 5 50.0% 5 50.0% 2.398 0.625 9.174 0.276 *

25-44 years old 20 29.4% 48 70.6% Ref. - - -

45-64 years old 20 26.3% 56 73.7% 0.857 0.413 1.779 0.679

+65 years old 6 31.6% 13 68.4% 1.107 0.369 3.322 0.855

Gender

Females 21 26.9% 57 73.1% 1.253 .647 2.427 0.504

Males 30 31.6% 65 68.4%

Language

English 40 32.5% 83 67.5% .617 .285 1.334 0.217

Other 11 22.9% 37 77.1%


10 years or more 41 29.7% 97 70.3% 1.029 .450 2.353 0.947

Less than 10 years 10 30.3% 23 69.7%

Education level



Annual income

$40,000 or more 10 21.3% 37 78.7% 1.827 .825 4.045 0.134

Less than $40,000 40 33.1% 81 66.9%

Last dental visit




Others 27 25.5% 79 74.5% 1.609 .816 3.174 0.168

Emergency 22 35.5% 40 64.5%


Yes 14 24.1% 44 75.9% 1.509 .734 3.102 0.262

No 36 32.4% 75 67.6%


Twice or more 36 25.9% 103 74.1% 2.225 1.005 4.927 0.045

Once or never 14 43.8% 18 56.2%


Yes or sometimes 38 29.2% 92 70.8% 1.002 .463 2.167 0.996

No 12 29.3% 29 70.7%




164

Table 66. Chi square analysis between IPC empowerment and some predictors

IPC empowerment

Poor Good OR

95% CI p value

n % n % Lower Upper

Age

18-24 years old 6 60.0% 4 40.0% 2.278 0.588 8.850 0.308 *

25-44 years old 27 39.7% 41 60.3% Ref. - - -

45-64 years old 30 39.5% 46 60.5% 0.990 0.507 1.934 0.977

+65 years old 11 55.0% 9 45.0% 1.855 0.679 5.076 0.225

Gender

Females 32 40.5% 47 59.5% 1.164 .636 2.131 0.623

Males 42 44.2% 53 55.8%

Language

English 54 43.5% 70 56.5% .926 .472 1.818 0.823

Other 20 41.7% 28 58.3%


10 years or more 59 42.4% 80 57.6% 1.130 .527 2.424 0.754

Less than 10 years 15 45.5% 18 54.5%

Education level



Annual income

$40,000 or more 19 40.4% 28 59.6% 1.132 .571 2.243 0.722

Less than $40,000 53 43.4% 69 56.6%

Last dental visit




Others 40 37.4% 67 62.6% 1.675 .889 3.156 0.109

Emergency 31 50.0% 31 50.0%


Yes 28 47.5% 31 52.5% .727 .385 1.375 0.326

No 44 39.6% 67 60.4%


Twice or more 57 40.7% 83 59.3% 1.456 .674 3.147 0.338

Once or never 16 50.0% 16 50.0%


Yes or sometimes 53 40.8% 77 59.2% 1.321 .656 2.658 0.435

No 20 47.6% 22 52.4%




165

Table 67. Chi square analysis between IPC decision-making and some predictors

IPC decision-making

Poor Good OR

95% CI p value

n % n % Lower Upper

Age

18-24 years old 7 70.0% 3 30.0% 2.475 0.590 10.417 0.312 *

25-44 years old 33 48.5% 35 51.5% Ref. - - -

45-64 years old 38 50.0% 38 50.0% 1.060 0.551 2.041 0.860

+65 years old 14 70.0% 6 30.0% 2.475 0.850 7.194 0.091

Gender

Females 37 46.8% 42 53.2% 1.561 .856 2.847 0.146

Males 55 57.9% 40 42.1%

Language

English 70 56.5% 54 43.5% .653 .334 1.275 0.210

Other 22 45.8% 26 54.2%


10 years or more 74 53.2% 65 46.8% 1.054 .492 2.258 0.892

Less than 10 years 18 54.5% 15 45.5%

Education level



Annual income

$40,000 or more 24 51.1% 23 48.9% 1.167 .595 2.291 0.652

Less than $40,000 67 54.9% 55 45.1%

Last dental visit




Others 59 55.1% 48 44.9% .763 .407 1.428 0.397

Emergency 30 48.4% 32 51.6%


Yes 32 54.2% 27 45.8% .923 .490 1.739 0.805

No 58 52.3% 53 47.7%


Twice or more 71 50.7% 69 49.3% 1.620 .736 3.564 .228

Once or never 20 62.5% 12 37.5%


Yes or sometimes 66 50.8% 64 49.2% 1.426 .704 2.888 0.323

No 25 59.5% 17 40.5%




166

Table 68. Summary table summarizing the results from table 54 to table 67

IPC (Continuous)

IPC (Dichotomous)

IPC general clarity score Last dental visit Reason for last dental visit

IPC elicitation and responsiveness score Reason for last dental visit


Annual income

IPC explanation of the condition score - Self-perceived oral health

IPC explanation of process of care score Self-perceived oral health Self-perceived oral health

IPC explanation of self-care score Self-perceived oral health Frequency of brushing


IPC empowerment score - -

IPC decision-making score Language -

167

Table 69. Spearman correlation between Interpersonal Processes of Care in Diverse Populations Questionnaire (IPC) subscales and CCOHLI and

OHLI and their components, REALD, REALD and dental knowledge test

Communicative

OHLI Score Critical OHLI

Score Score CCOHLI

OHLI reading

weighted

score

OHLI

numeracy

weighted

score

OHLI total

score

REALD-30

score REALM score

Dental

Knowledge

weighted

score

General clarity

score

Correlation

Coefficient 0.057 0.088 0.071 0.129 0.09 0.118 0.142 .188* 0.142

Elicitation and

responsiveness

score

Correlation

Coefficient -.274** -.159* -.238** -0.124 -.175* -.162* -0.115 -.180* -0.086

Explanation of

the condition

score

Correlation

Coefficient -.198** -0.105 -.154* -0.023 -0.13 -0.099 -0.048 -0.097 -0.155

Explanation of

process of care

score

Correlation

Coefficient -.172* -0.085 -0.128 -0.067 -0.069 -0.084 -0.033 -0.071 -0.03

Explanation of

self-care score

Correlation

Coefficient -.218** -.195* -.214** 0.018 -.160* -0.127 0.062 -0.041 -0.086

Empowerment

score

Correlation

Coefficient -.232** -0.145 -.176* -0.044 -.171* -.172* 0.034 -0.082 -0.157

Decision-making

score

Correlation

Coefficient -.151* -0.107 -0.131 0.044 -0.131 -0.093 0.101 0.042 -0.033


** Correlation is significant at the 0.01 level (2-tailed).

168

Table 70. Association between different oral health literacy tests and dental knowledge test scores and

IPC general clarity level

IPC general clarity

p value * Poor Good



Communicative OHLI Score

2.7 0.76 0.12 2.92 0.66 0.06 0.113

Critical OHLI Score

2.78 0.86 0.14 2.99 0.79 0.07 0.175

Score CCOHLI 2.73 0.71 0.11 2.95 0.65 0.06 0.113

OHLI reading weighted score

40.32 6.83 1.09 42.19 5.38 0.47 0.095

OHLI numeracy weighted score

39.08 6.21 0.98 39.49 7.07 0.62 0.419

OHLI total score

79.66 10.83 1.73 81.81 10.76 0.95 0.222

REALD-30 score 59 11.46 1.81 62.33 6.14 0.54 0.084

Dental Knowledge

weighted score 47.79 23.76 3.76 53.07 21.69 1.88 0.159

* p value obtained from Mann-Whitney U test.

169


IPC elicitation and responsiveness level


p value * Poor Good




2.49 0.68 0.13 2.94 0.67 0.06 0.001

Critical OHLI Score

2.56 0.85 0.16 3.01 0.78 0.07 0.006

Score CCOHLI 2.52 0.68 0.13 2.97 0.64 0.05 0.001


42.01 5.38 1.02 41.71 5.87 0.49 0.696


36.45 8.38 1.61 39.96 6.42 0.54 0.027

OHLI total score

78.65 12.66 2.44 81.82 10.35 0.88 0.191

REALD-30 score 22.56 5.54 1.07 23.54 4.97 0.42 0.517

Dental Knowledge

weighted score 53.57 24.87 4.7 51.52 21.76 1.81 0.796


170


IPC explanation of the condition level


p value * Poor Good




2.55 0.83 0.16 2.95 0.63 0.05 0.009

Critical OHLI Score

2.67 0.95 0.19 3 0.76 0.06 0.1

Score CCOHLI 2.6 0.84 0.17 2.97 0.6 0.05 0.024


41.4 5.76 1.09 41.83 5.79 0.49 0.710


37.59 5.35 1.01 39.85 7.02 0.59 0.012

OHLI total score

78.99 8.67 1.64 81.92 11.04 0.94 0.028

REALD-30 score 23.11 4.76 0.9 23.51 5.07 0.43 0.606

dental Knowledge

weighted score 47.06 21.48 4.06 53.11 22.3 1.86 0.241


171


IPC explanation of process of care level


p value * Poor Good




2.71 0.6 0.13 2.91 0.69 0.06 0.077

Critical OHLI Score

2.83 0.77 0.17 2.97 0.8 0.07 0.376

Score CCOHLI 2.76 0.61 0.14 2.94 0.66 0.05 0.128


40.43 6.94 1.48 41.96 5.58 0.46 0.209


38.64 7.14 1.52 39.6 6.77 0.56 0.574

OHLI total score

79.07 10.9 2.32 81.78 10.67 0.89 0.225

REALD-30 score 21.68 6.79 1.45 23.71 4.66 0.39 0.180

dental Knowledge

weighted score 45.72 23.38 4.99 53.06 21.96 1.8 0.138


172


IPC explanation of self-care level


p value * Poor Good




2.69 0.85 0.12 2.97 0.58 0.05 0.045

Critical OHLI Score

2.72 0.99 0.14 3.05 0.69 0.06 0.088

Score CCOHLI 2.7 0.86 0.12 3 0.53 0.05 0.039


42.13 5.9 0.83 41.6 5.74 0.53 0.502


39 5.98 0.85 39.67 7.14 0.66 0.180

OHLI total score

81.13 9.4 1.33 81.54 11.26 1.05 0.263

REALD-30 score 23.82 5.16 0.73 23.28 4.96 0.46 0.457

dental Knowledge

weighted score 50.24 22.18 3.14 52.89 22.28 2.03 0.539


173


IPC empowerment level

IPC empowerment

p value * Poor Good




2.72 0.76 0.09 3 0.59 0.06 0.006

Critical OHLI Score

2.85 0.91 0.11 3.04 0.71 0.07 0.276

Score CCOHLI 2.78 0.77 0.09 3.02 0.54 0.05 0.070


41.38 6 0.7 42.08 5.58 0.57 0.431


38.86 5.63 0.66 39.97 7.55 0.77 0.033

OHLI total score

80.34 9.69 1.14 82.31 11.36 1.17 0.028

REALD-30 score 23.37 5.39 0.63 23.46 4.71 0.48 0.820

dental Knowledge

weighted score 47.38 22.16 2.58 55.7 21.57 2.18 0.016


174


IPC decision-making level

IPC decision-making

p value * Poor Good

Mean SD Standard

error Mean SD

Standard error


2.77 0.74 0.08 3.01 0.58 0.06 0.031

Critical OHLI Score

2.85 0.9 0.09 3.08 0.66 0.07 0.166

Score CCOHLI 2.81 0.76 0.08 3.04 0.5 0.06 0.062


42.06 5.5 0.58 41.46 6.06 0.68 0.716


39.21 5.72 0.6 39.81 7.87 0.88 0.111

OHLI total score

81.36 9.19 0.97 81.56 12.24 1.39 0.180

REALD-30 score 23.71 5.03 0.53 23.09 4.98 0.56 0.319

dental Knowledge

weighted score 50.74 21.72 2.28 53.67 22.66 2.52 0.363


175

Table 77. Chi square analysis between oral health literacy level and IPC general clarity level

IPC general clarity

Poor Good OR

95% CI p value

n % n % Lower Upper

CCOHLI Level

Adequate 19 20.2% 75 79.8% 1.453 0.715 2.959 0.300

Inadequate 21 26.9% 57 73.1%

OHLI Level

Adequate 26 23.0% 87 77.0% 1.087 0.507 2.336 0.830


REALD-30 Level

High 10 15.4% 55 84.6% 2.232 1.006 4.950 0.045


176

Table 78. Chi square analysis between oral health literacy level and IPC elicitation and responsiveness

level


Poor Good OR

95% CI p value

n % n % Lower Upper

CCOHLI Level

Adequate 8 8.5% 86 91.5% 3.460 1.422 8.403 0.004

Inadequate 19 24.4% 59 75.6%

OHLI Level

Adequate 15 13.3% 98 86.7% 1.912 0.824 4.444 0.127


REALD-30 Level

High 8 12.3% 57 87.7% 1.592 0.653 3.891 0.303


177

Table 79. Chi square analysis between oral health literacy level and IPC explanation of the condition

level


Poor Good OR

95% CI p value

n % n % Lower Upper

CCOHLI Level

Adequate 8 8.5% 86 91.5% 3.333 1.361 8.197 0.006

Inadequate 18 23.7% 58 76.3%

OHLI Level

Adequate 16 14.2% 97 85.8% 1.818 0.790 4.184 0.156


REALD-30 Level

High 10 15.4% 55 84.6% 1.164 0.501 2.710 0.723


178

Table 80. Chi square analysis between oral health literacy level and IPC explanation of process of care

level


Poor Good OR

95% CI p value

n % n % Lower Upper

CCOHLI Level

Adequate 6 6.4% 88 93.6% 3.311 1.206 9.091 0.015

Inadequate 14 18.4% 62 81.6%

OHLI Level

Adequate 14 12.4% 99 87.6% 1.285 0.503 3.289 0.599


REALD-30 Level

High 6 9.2% 59 90.8% 1.808 0.669 4.902 0.238


179

Table 81. Chi square analysis between oral health literacy level and IPC explanation of self-care level


Poor Good OR

95% CI p value

n % n % Lower Upper

CCOHLI Level

Adequate 21 22.3% 73 77.7% 2.028 1.034 3.968 0.038

Inadequate 28 36.8% 48 63.2%

OHLI Level

Adequate 34 30.1% 79 69.9% 1.033 0.506 2.105 0.930


REALD-30 Level

High 18 27.7% 47 72.3% 1.176 0.593 2.336 0.641


180

Table 82. Chi square analysis between oral health literacy level and IPC empowerment level

IPC empowerment

Poor Good OR

95% CI p value

n % n % Lower Upper

CCOHLI Level

Adequate 33 34.7% 62 65.3% 1.980 1.068 3.676 0.029

Inadequate 39 51.3% 37 48.7%

OHLI Level

Adequate 49 43.0% 65 57.0% 1.052 0.543 2.037 0.880


REALD-30 Level

High 28 43.1% 37 56.9% 1.008 .539 1.883 0.980


181

Table 83. Chi square analysis between oral health literacy level and IPC decision-making level

IPC decision-making

Poor Good OR

95% CI p value

n % n % Lower Upper

CCOHLI Level

Adequate 43 45.3% 52 54.7% 1.961 1.060 3.623 0.031

Inadequate 47 61.8% 29 38.2%

OHLI Level

Adequate 60 52.6% 54 47.4% 1.135 0.587 2.193 0.707


REALD-30 Level

High 37 56.9% 28 43.1% 0.786 0.422 1.466 0.450


182

Table 84. Summary table summarizing the results from table 70 to table 83

Oral health literacy score (Continuous)

Oral Health literacy level (Dichotomous)

IPC general clarity score - REALD-30

IPC elicitation and responsiveness score

Communicative OHLI score

Critical OHLI score

CCOHLI score

OHLI numeracy score

CCOHLI

IPC explanation of the condition score Communicative OHLI score

CCOHLI score

OHLI numeracy score

Total OHLI score

CCOHLI

IPC explanation of process of care score

- CCOHLI

IPC explanation of self-care score Communicative OHLI score

CCOHLI score

CCOHLI

IPC empowerment score Communicative OHLI score

OHLI numeracy score

Total OHLI score

Dental Knowledge test score

CCOHLI

IPC decision-making score Communicative OHLI score CCOLHI

183

Table 85: Logistic regression model for IPC general clarity level (poor)

Independent Variables Model 1: OHLI score 1

(n=146) Model 2: CCOHLI score 2

(n=150) Model 3: REALD-30 score 3

(n=149) Model 4: All instrument 4

(n=144)

Odds ratio

95% CI of odds ratio Odds ratio

Odds ratio Odds ratio


95% CI of odds ratio

Lower Upper Lower Upper Lower Upper Lower Upper

Age 0.993 0.958 1.028 0.994 0.961 1.029 0.993 0.96 1.028 0.997 0.962 1.034

Gender (male) 0.868 0.359 2.097 0.858 0.36 2.043 0.805 0.338 1.919 0.879 0.362 2.133

Native language (other than English)

1.687 0.594 4.792 1.701 0.613 4.716 1.723 0.63 4.714 1.726 0.601 4.955


1.644 0.485 5.577 1.349 0.417 4.366 1.292 0.411 4.063 2.055 0.561 7.52


1.233 0.432 3.52 1.09 0.394 3.016 0.993 0.357 2.766 1.225 0.425 3.532

Annual income (less than $40,000)

0.361 0.125 1.044 0.36 0.126 1.026 0.343* 0.12 0.979 0.358 0.123 1.04


0.238** 0.081 0.704 0.327* 0.114 0.936 0.302* 0.106 0.858 0.272* 0.089 0.829


2.884* 1.118 7.435 2.918* 1.167 7.293 2.956* 1.16 7.534 3.011* 1.141 7.948

Attending regular check-up (no)

1.237 0.396 3.865 1.065 0.336 3.376 1.242 0.406 3.804 1.125 0.353 3.588


1.416 0.531 3.776 1.476 0.564 3.864 1.581 0.604 4.141 1.362 0.5 3.707

Dental knowledge score 0.997 0.974 1.02 0.995 0.974 1.017 1 0.978 1.022 0.998 0.974 1.021

OHLI total score 1.006 0.955 1.061 - - - - - - 1.025 0.962 1.093

CCOHLI total score - - - 0.783 0.416 1.474 - - - 0.77 0.399 1.486

REALD-30 score - - - - - - 0.944 0.858 1.04 0.944 0.829 1.074

*P<0.05

** P<0.01

*** P<0.001

1. -2 Log-likelihood = 131.262; Cox & Snell R2 = 0.142; Nagelkerke R2 = 0.218; Hosmer and Lemeshow chi-squared test=5.033, d.f. = 8, P = 0.754




184

Table 86: Logistic regression model for IPC elicitation and responsiveness level (poor)


Model 1: OHLI score 1




(n=144)

Odds ratio


Odds ratio





Age 0.996 0.96 1.033 0.992 0.954 1.031 0.997 0.962 1.034 0.995 0.957 1.036

Gender (male) 1.172 0.453 3.033 1.179 0.418 3.324 1.145 0.439 2.987 1.115 0.399 3.117


1.026 0.322 3.274 1.169 0.349 3.913 1.03 0.331 3.204 1.163 0.339 3.991


1.128 0.299 4.265 2.103 0.527 8.389 1.321 0.372 4.687 2.047 0.462 9.073


1.278 0.436 3.753 1.572 0.496 4.985 1.26 0.435 3.648 1.497 0.463 4.838


1.858 0.454 7.606 1.886 0.449 7.925 1.988 0.496 7.97 1.837 0.429 7.859


0.773 0.267 2.239 0.963 0.299 3.103 0.82 0.284 2.366 0.902 0.271 2.998


1.081 0.389 3.008 1.027 0.347 3.042 1.045 0.377 2.895 1.004 0.327 3.079

Attending regular check-up (no) 2.371 0.589 9.543 1.249 0.257 6.058 2.295 0.57 9.242 1.437 0.299 6.898


1.423 0.505 4.007 1.311 0.413 4.158 1.445 0.514 4.061 1.266 0.393 4.078

Dental knowledge score 1.012 0.989 1.036 1.018 0.994 1.043 1.014 0.991 1.038 1.017 0.992 1.043

OHLI total score 0.973 0.929 1.019 - - - - - - 0.996 0.929 1.068

CCOHLI total score - - - 0.329** 0.16 0.679 - - - 0.325** 0.155 0.683

REALD-30 score - - - - - - 0.943 0.855 1.04 0.98 0.846 1.136

*P<0.05

** P<0.01

*** P<0.001





185

Table 87: Logistic regression model for IPC explanation of the condition level (poor)






(n=143)

Odds ratio


Odds ratio





Age 1.037 0.996 1.08 1.029 0.988 1.071 1.033 0.995 1.072 1.034 0.99 1.08

Gender (male) 1.256 0.471 3.35 1.138 0.401 3.227 1.217 0.456 3.246 1.06 0.367 3.062


0.633 0.191 2.098 0.784 0.227 2.707 0.621 0.189 2.041 0.789 0.225 2.765


0.719 0.161 3.224 1.262 0.283 5.63 0.856 0.209 3.51 1.06 0.209 5.373


0.655 0.211 2.029 0.728 0.22 2.402 0.73 0.241 2.215 0.724 0.212 2.469


0.926 0.245 3.494 1.049 0.25 4.395 0.9 0.247 3.277 1.176 0.268 5.155


0.45 0.145 1.394 0.297 0.084 1.047 0.415 0.136 1.268 0.299 0.082 1.086


1.422 0.51 3.965 1.265 0.435 3.676 1.222 0.451 3.308 1.402 0.462 4.255

Attending regular check-up (no)

1.896 0.541 6.641 1.345 0.324 5.586 1.969 0.568 6.825 1.306 0.305 5.592


3.773* 1.216 11.709 4.715* 1.268 17.529 3.458* 1.139 10.495 4.968* 1.321 18.68


OHLI total score 0.986 0.939 1.036 - - - - - - 0.99 0.925 1.06

CCOHLI total score - - - 0.439* 0.21 0.917 - - - 0.457* 0.215 0.971

REALD-30 score - - - - - - 0.993 0.89 1.109 1.058 0.899 1.245

*P<0.05

** P<0.01

*** P<0.001





186

Table 88: Logistic regression model for IPC explanation of process of care level (poor)






(n=143)

Odds ratio


Odds ratio





Age 1.017 0.974 1.062 0.996 0.952 1.042 1.009 0.968 1.053 1.006 0.96 1.054

Gender (male) 0.475 0.158 1.429 0.362 0.11 1.191 0.52 0.171 1.582 0.321 0.093 1.104


0.924 0.249 3.429 1.191 0.302 4.696 0.805 0.217 2.989 1.489 0.367 6.041


1.051 0.202 5.463 1.376 0.272 6.968 1.277 0.275 5.942 1.479 0.251 8.723


1.66 0.439 6.286 1.833 0.456 7.361 1.858 0.503 6.869 1.785 0.42 7.592


0.593 0.136 2.584 0.649 0.139 3.019 0.502 0.121 2.089 0.786 0.161 3.836


2.604 0.748 9.057 1.594 0.439 5.784 2.239 0.662 7.574 1.882 0.485 7.307


1.878 0.602 5.86 1.855 0.568 6.06 1.583 0.512 4.893 2.144 0.645 7.123



3.862* 1.053 14.163 5.168* 1.168 22.873 3.409 0.967 12.022 5.835* 1.213 28.068

Dental knowledge score 0.958* 0.925 0.992 0.98 0.951 1.011 0.969 0.938 1.001 0.971 0.936 1.008

OHLI total score 1.007 0.952 1.065 - - - - - - 1.04 0.965 1.121

CCOHLI total score - - - 0.806 0.312 2.085 - - - 0.811 0.311 2.115

REALD-30 score - - - - - - 0.98 0.862 1.114 0.959 0.79 1.165

*P<0.05

** P<0.01

*** P<0.001





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Table 89: Logistic regression model for IPC explanation of process of self-care level (poor)






(n=143)

Odds ratio


Odds ratio





Age 0.991 0.963 1.02 0.981 0.952 1.01 0.986 0.958 1.014 0.98 0.949 1.011

Gender (male) 1.459 0.682 3.12 1.415 0.639 3.131 1.357 0.627 2.938 1.315 0.574 3.011


0.587 0.227 1.516 0.583 0.219 1.555 0.546 0.208 1.43 0.579 0.204 1.645


1.441 0.48 4.322 1.721 0.578 5.119 1.312 0.459 3.752 1.895 0.557 6.454


1.062 0.448 2.518 1.11 0.457 2.696 1.116 0.47 2.649 1.302 0.504 3.361


1.191 0.463 3.064 1.208 0.455 3.208 1.152 0.446 2.977 1.26 0.453 3.502


0.735 0.312 1.733 0.668 0.267 1.669 0.636 0.265 1.529 0.495 0.184 1.332


1.311 0.584 2.944 1.154 0.499 2.671 1.122 0.499 2.524 1.163 0.481 2.814



1.677 0.74 3.801 1.733 0.731 4.11 1.711 0.756 3.871 1.702 0.686 4.221


OHLI total score 1.01 0.967 1.055 - - - - - - 0.991 0.933 1.053


REALD-30 score - - - - - - 1.1 0.996 1.213 1.181* 1.037 1.344

*P<0.05

** P<0.01

*** P<0.001





188

Table 90: Logistic regression model for IPC empowerment level (poor)






(n=144)

Odds ratio


Odds ratio





Age 1.009 0.981 1.037 1.002 0.975 1.03 1.005 0.978 1.032 1.004 0.975 1.033

Gender (male) 1.164 0.571 2.372 1.159 0.565 2.376 1.126 0.552 2.295 1.041 0.496 2.188


0.923 0.39 2.186 0.84 0.355 1.988 0.786 0.332 1.862 0.938 0.38 2.314


1.871 0.661 5.3 1.912 0.699 5.232 1.613 0.6 4.335 2.251 0.748 6.774


1.246 0.552 2.81 1.173 0.52 2.642 1.205 0.539 2.694 1.372 0.591 3.184


0.783 0.333 1.845 0.802 0.341 1.886 0.786 0.336 1.834 0.809 0.334 1.964


0.569 0.258 1.258 0.571 0.252 1.294 0.532 0.24 1.178 0.476 0.2 1.134


1.757 0.809 3.816 1.567 0.732 3.356 1.532 0.715 3.28 1.625 0.728 3.626



1.376 0.644 2.943 1.457 0.674 3.152 1.513 0.709 3.23 1.345 0.604 2.993

Dental knowledge score 0.979* 0.961 0.998 0.987 0.969 1.005 0.977* 0.959 0.996 0.979* 0.959 0.999

OHLI total score 1.011 0.972 1.052 - - - - - - 1.003 0.953 1.055

CCOHLI total score - - - 0.589 0.339 1.021 - - - 0.553* 0.311 0.984

REALD-30 score - - - - - - 1.071 0.985 1.164 1.094 0.981 1.221

*P<0.05

** P<0.01

*** P<0.001





189

Table 91: Logistic regression model for IPC decision-making level (poor)






(n=144)

Odds ratio


Odds ratio





Age 1.003 0.976 1.03 1 0.973 1.027 1 0.974 1.026 1 0.971 1.029

Gender (male) 1.38 0.686 2.776 1.477 0.726 3.002 1.358 0.673 2.741 1.325 0.638 2.752


0.548 0.231 1.3 0.469 0.198 1.108 0.483 0.204 1.145 0.522 0.212 1.288


1.722 0.605 4.9 1.835 0.672 5.014 1.481 0.546 4.018 2.069 0.689 6.215


1.109 0.494 2.49 1.061 0.473 2.381 1.093 0.488 2.45 1.245 0.536 2.889


1.033 0.448 2.381 1.033 0.448 2.385 1.035 0.452 2.374 1.05 0.442 2.496


0.755 0.341 1.672 0.864 0.386 1.936 0.695 0.312 1.548 0.705 0.298 1.67


0.634 0.293 1.373 0.559 0.257 1.214 0.558 0.258 1.207 0.538 0.238 1.216



1.531 0.726 3.231 1.475 0.696 3.122 1.674 0.792 3.541 1.403 0.64 3.073

Dental knowledge score 0.982* 0.964 0.999 0.986 0.969 1.004 0.979* 0.961 0.997 0.979* 0.96 0.999

OHLI total score 1.013 0.976 1.052 - - - - - - 1.001 0.953 1.052


REALD-30 score - - - - - - 1.079 0.995 1.171 1.107 0.993 1.235

*P<0.05

** P<0.01

*** P<0.001





190

Table 92 . Summary table summarizing the results from table 85 to table 91

Model 1: OHLI score

Model 2: CCOHLI

score

Model 3: REALD-30 score

Model 4: All instruments

IPC general clarity Last dental visit


Last dental visit


Annual income

Last dental visit


Last dental visit



- CCOHLI score - CCOHLI score

IPC explanation of condition

- - Self-perceived oral health


CCOHLI score



Dental knowledge score


- Self-perceived oral health


- CCOHLI score - CCOHLI score

REALD-30 score

IPC empowerment Dental knowledge score

- Dental knowledge score


CCOHLI score

IPC decision-making Dental knowledge score

CCOHLI score Dental knowledge score


CCOHLI score

191

Table 93: Frequency of responses to oral health related barrier questions and to questions about the

pattern of communication between patients and undergraduate students (n = 155)

% of the total

no. n=155

% of the people who

answered this Q

Have you received any dental information about the cause of your dental

problems and how to prevent them during your initial visits to the Faculty of

Dentistry Clinic’s?

Yes 61.3 95 61.3

No 38.7 60 38.7

How did you receive this information?

Verbally 60.6 94 98.9

In writing (e.g. pamphlet) 0.6 1 1.1

Electronically (referral to a website or via e-mail) - - -

Skipped 38.7 60

Did you understand the information that was given to you?

Yes 56.8 88 92.6

No 4.5 7 7.4

Skipped 38.7 60

What was/were the reason/s for not understanding the given information?

The information was complicated. 2.6 4 57.1

The dentist did not spend enough time clarifying them. 1.3 2 28.6

The dentist used terms that I did not understand. - - -

The clinical area was noisy and distractive. - - -

I was embarrassed to ask for clarification. 0.6 1 14.3

Skipped 95.5 153

Were you given time to ask questions about your dental status and treatment?

Yes 88.4 137 88.4

No 11.6 18 11.6

Were all your questions answered to your satisfaction?

Yes 84.5 131 95.6

No 3.9 6 4.4

Skipped 11.6 18

Did you receive any instructions about improving your oral hygiene?

Yes 53.5 83 53.5

No 46.5 72 46.5

Do you plan to follow these instructions?

Yes 53.5 83 100

No - - -

Skipped 46.5 72

If you have answered “NO” to question 8, Why?

I cannot see the value of these instructions.

- - -


192

I do not feel that applying theses instructions to my daily life will help

improving my oral hygiene and prevent my future problems.

- - -

I do not have time to perform these practices. - - -

The cost of oral hygiene aids (e.g. tooth brush, floss and toothpaste) is high. - - -

My teeth hurt when I brush them. - - -

My gum bleeds when I brush my teeth. - - -

Skipped 100 155

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Table 94: Frequency of responses to oral health related barrier questions and to questions about the

pattern of communication between patients and undergraduate students (subdivided based on the

student year)

3rd year students 4th year students

p value* Have you received any dental information about the cause of

your dental problems and how to prevent them during your

initial visits to the Faculty of Dentistry Clinic’s?

n % n %

Yes 69 57.5% 21 77.8% 0.051 No 51 42.5% 6 22.2%

How did you receive this information?

Verbally 70 100.0% 20 95.2% 0.231* In writing (e.g. pamphlet) 0 0.0% 1 4.8%

Electronically (referral to a website or via e-mail) 0 0.0% 0 0.0%

Did you understand the information that was given to you?

Yes 68 97.1% 21 100.0% 1.000* No 2 2.9% 0 0.0%

What was/were the reason/s for not understanding the given

information?

The information was complicated. 3 50.0% 0 0.0%

-

The dentist did not spend enough time clarifying them. 2 33.3% 0 0.0%

The dentist used terms that I did not understand. 0 0.0% 0 0.0%

The clinical area was noisy and distractive. 0 0.0% 0 0.0%

I was embarrassed to ask for clarification. 1 16.7% 0 0.0%

Were you given time to ask questions about your dental status

and treatment?

Yes 99 85.3% 25 96.2% 0.196* No 17 14.7% 1 3.8%

Were all your questions answered to your satisfaction?

Yes 98 93.3% 26 100.0% 0.196* No 7 6.7% 0 0.0%

Did you receive any instructions about improving your oral

hygiene?

Yes 59 49.2% 21 77.8% 0.007 No 61 50.8% 6 22.2%

Do you plan to follow these instructions?

Yes 62 98.4% 21 100.0% 1.000*

No 1 1.6% 0 0.0%

*p value obtained from Fisher exact test

194

Discussion

195

Part 1 and 2:

Development of CCOHLI

One of the main objectives of this study was to develop and validate a new instrument to

measure communicative and critical oral health literacy for adults to complement other

available functional oral health literacy instruments and cover the three concepts of health

literacy as defined by Nutbeam7. To the best of our knowledge, this is the first instrument

developed to assess communicative and critical oral health literacy in adult dental patients. As

stated previously, the CCOHLI was modeled on a previously validated medical instrument which

was developed to measure communicative and critical health literacy among diabetic patients54.

The text of the original instrument was modified to be appropriate for the dental field. The face

and content validity was assessed by a panel of experts in the fields of community and

preventive dentistry and public health who assessed the suitability of the questions for the

dental setting.

Internal and test-retest reliability of CCOHLI

CCOHLI displayed high internal consistency and good test-retest reliability in our study. The

internal consistency did not increase significantly with the sequential deletion of test items.

Because the deletion of any item did not result in an increase in Cronbach’s alpha value, it was

decided to retain all items in the instrument.

OHLI, REALD-30, REALM and dental Knowledge Test Scores

The mean oral health knowledge test and OHLI scores in this study were lower than in our

previous study72 (Knowledge test: 52.2 ± 22.3 vs. 57.5 ± 26.0 and OHLI:81.4 ± 10.7 vs. 87.3 ±

10.2). Similar to other oral health literacy instruments, an arbitrary cutoff point of <80 was used

to indicate marginal or inadequate oral health literacy. This cutoff point represents the lowest

30-35 percentile of the distribution of the OHLI score. This cutoff point indicated 30% of our

sample are having marginal or inadequate oral health literacy. Participants performed better in

the reading comprehension in comparison to numeracy section (41.9 ± 5.8 vs. 39.93 ± 6.82),

indicating better reading comprehension skills and lower numeracy skills among the

participants. In contrast to OHLI, REALD-30 had a mean score of 23.4 ± 5.0, which is in the

highest end of the previously reported data. REALD-30 scores varied between different settings.

196

Previous data showed that REALD-30 scores at a private dental office78, an outpatient medical

clinic68, dental school80 and a special supplemental nutrition clinic for low-income pregnant

women81 were 23.9 ± 1.3, 19.8 ± 6.4, 20.7 ± 5.5 and 16.4 ± 5.0, respectively. A higher percentage

of participants had marginal or low level of oral health literacy based on the REALD-30 in

comparison to OHLI. This can be explained by the difference in the concept and the selection of

the cutoff points between both tests. The REALD-30 utilizes the word recognition concept as an

indicator of the oral health literacy. Most of the words in columns 1 to 3 of the test were within

the grasp of the average person whose native language was English, while some of the words in

column 4 were difficult and complex terms even for people whose first language was English. It

has to be emphasized that word recognition does not imply understanding. Individuals with a

background in English literature or Latin can pronounce most of the difficult medical and dental

terms even if they were not exposed to them previously. Similar to the OHLI and REALD-30, the

REALM scores were accumulated to the positive end of the scale (61.6 ± 7.8), with a higher

percentage of participants (about 80%) at the adequate level of the health literacy compared to

oral health literacy level. This can be explained by the higher exposure and familiarity of the

patient to the medical environment in comparison to the dental setting. The skewness of the

results and accumulation of most of the subjects on the positive side of the scoring scale can be

referred to the fact that most of our sample represented participants who were seeking dental

treatment for the treatment of their oral health problems (78%), were native English speakers

(71%) and had a college degree or more (60%).

Participants in this study had better critical skills in comparison to their communicative

skills, indicating more confidence in critiquing the oral health information and lower confidence

in communicating their oral health issues with the oral health professionals. It is well known that

patient-dentist communication is an interactive process91. This communication difficulty can be

attributed to either inadequate communicative oral health literacy skills among some of the

participants and/or inadequate communication skills among some of the oral health

professionals. Inappropriate communication language by the oral health professional might act

as a barrier to future communication. Oversimplified communication language with highly

literate patients might irritate them, while complicated communication language with illiterate

patients might leave them embarrassed and prevent future communication.

197

Convergent and discriminant validity of OHLI and CCOHLI

At the time of OHLI development, its convergent validity was established against a medical

functional oral health literacy instrument (TOFHLA). At that time, no other oral health literacy

test was available to be correlated with OHLI. In this study, we evaluated the convergent validity

against one of the word recognition oral health literacy instruments (REALD-30). REALD-30 was

selected over the TOFHLiD, which was developed for parents of pediatric dental patients, due to

its suitability for general adult patient population. To test OHLI’s discriminant validity, we

examined the degree to which OHLI was not similar to a medical word recognition test (REALM).

We hypothesized that there would be a great degree of association between the two dental

tests (OHLI and REALD-30) in comparison to the association between the dental and medical

instruments (OHLI and REALM).

Results of this study indicated moderate statistically significant positive associations

between the OHLI and both REALD-30 and REALM scores. The degree of association was

comparable, with slightly higher correlation coefficient for the REALM in comparison to the

REALD-30. This can be explained by the similarity and the strong association between both

instruments, by the modeling of the former on the latter, by the overlap between the health

literacy and the oral health literacy, and because both of them measure functional health

literacy.

The convergent and discriminant validities of the CCOHLI were assessed against both (OHLI

and REALD-30) and REALM, respectively. We hypothesized that the degree of association

between the dental tests (CCOHLI, and OHLI and REALD-30) would be greater than between the

dental and medical instruments (CCOHLI and REALM). The results confirmed this hypothesis

with a significant weak correlation between CCOHLI and REALD-30, and the lack of association

between CCOHLI and REALM. It has to be emphasized that CCOHLI is different than other oral

health literacy instruments in the fact that it is self-reported, which might explain the weak

association that was found between CCOHLI and REALD-30 and lack of significant association

between CCOHLI and OHLI.

Developing a conceptual framework for the association between oral health literacy

and different independent variables and oral health outcomes

We relied on the framework proposed by Baker92 to develop a conceptual framework for

198

the factors or outcomes affecting or affected by oral health literacy level (Figure 5). The

conceptual framework proposed different socio-demographic variables to be associated with

the oral health literacy. In addition, the dental knowledge was viewed as an important variable

that might facilitate oral health literacy. The dentist-patient communication quality was also

proposed to affect the oral health literacy and/or to be affected by the level of the oral health

literacy. Furthermore, different oral health behaviors and outcomes were suggested to be

affected by the oral health literacy level.

Association between oral health literacy and socio-demographics

The following socio-demographic variables were evaluated in this study: age, gender, native

language, time lived in Canada, education and annual income. Significant associations were

detected between OHLI and native language, time spent in Canada, and annual household

income, with all the relationships in the expected directions. Only English as a native language

and time being in Canada was confirmed as significant predictors at the multivariate level. It has

to be emphasized that the associations between English as a native language, annual income or

time spent in Canada and oral health literacy were not evaluated previously in the literature but

similar associations were reported in the medical field93-95. In contrast to OHLI, none of the

socio-demographic variables was significantly associated with REALD-30 or CCOHLI. The lack of

association between oral health literacy, and age and gender is in agreement with the body of

the literature (Table 3). However, the lack of association between educational level and oral

health literacy (measured using REALD-3) is not consistent with the previous reports. As

reported in Table 3, a positive association between educational level and oral health literacy was

reported in all the 4 studies that used REALD-30. On the contrary, lack of the association

between OHLI and education level is in agreement with our previous study72. This lack of

association may be explained in part by the high level of education (59% with a college or

university education) among the participants for whom health literacy may not be an issue.

Association between oral health literacy and oral hygiene and dental attendance

behaviors

The following variables were selected to reflect the oral hygiene and dental attendance

behaviors: time and reason for last dental visit, attendance of regular dental check-ups and

199

frequency of tooth brushing and flossing. No association was observed between any of these

variables and REALD-30 or OHLI. Nevertheless, significant associations were found between all

the variables and CCOHLI, with all the relationships in the expected direction. Only one of these

variables (frequency of flossing) remained as a significant predictor at the multivariate level.

Several studies evaluated the association between oral health literacy and dental

attendance (Table 3), with most studies reporting no significant association between them. On

the other hand, the association between oral health literacy and oral health behavior was not a

consistent finding in the previous studies, with controversial results among the studies. This lack

of consistency can be attributed to the heterogeneity of the current studies in terms of

population and methodology.

Association between oral health literacy and self-perceived oral health status

Self-perceived oral health status was included in our model as one of the oral health

outcomes that might be affected by oral health literacy. We hypothesized an increase in the

self-rating of oral health status with the increase in oral health literacy. This hypothesis was

confirmed for CCOHLI at the bivariate and multivariate levels but not for REALD-30 and OHLI. As

stated previously, controversial results were found in the literature about the association

between oral health literacy and self-perceived oral health status (Table 3), with half of the

studies reporting significant associations between them.

A higher percentage of the participants in this study reported fair or poor oral health status

in comparison to the data reported by the Canadian adults in the Canadian Health Measures

Survey (CHMS)96 (51.4 vs. 15.5%). A plausible explanation for this difference can be the

difference of the studied population. In contrast to the CHMS, the participants in our study were

seeking treatment for their various dental problems (about 79% of the participants indicated “to

treat dental problem” as the reason for being a patient at the Faculty). In addition, about 73% of

the participants in the present study reported low annual income (less than $40,000).

Association between oral health literacy and oral health-related quality of life

The prevalence of impacts reported in this study was higher than the reported prevalence of

impacts for adult Canadians (61.7% vs. 19.5%)97. This higher prevalence can be explained by the

fact that the participants in this study were seeking dental treatment for their oral health

200

problems in comparison to the results from a survey, in which participants may not have dental

problems that will impact their quality of life. It has to be emphasized that the most commonly

reported impacts were within the dimensions (physical pain, psychological discomfort and

psychological disability), which have relatively less severe impact in comparison to other

domains (functional limitation, social disability and handicap).

In contrast to previous studies (Table 3), no significant association was found between oral

health literacy and severity and extent of oral health impacts for any of the three oral health

literacy instruments used in this study. In contrast, prevalence of the impacts was significantly

associated with the level of communicative and critical oral health literacy. Higher prevalence of

impacts has been observed in participants with inadequate communicative and critical oral

health literacy. Different results were obtained when the data were analyzed for different

domains of OHIP-14. Significant negative correlations were observed between the REALD-30 and

OHLI scores and the extent and severity of some of the domains, reflecting one of the

limitations of using the extent and the severity of the whole scale in comparison to the domains.

Interestingly, most of these associations were with the domains that have relatively severe

impact on the quality of life (functional limitation, social disability and handicap). To our

knowledge, this is the first study reporting the association between oral health literacy and

different OHIP-14 domains.

We did not include all of the variables used to summarize OHIP-14 in the multivariate

analysis to avoid any possible interaction between them. The OHIP-14 severity, extent and

prevalence were tried alternatively on the different multivariate models to represent the oral

health-related quality of life. However, only prevalence remained as a significant predictor for

the OHLI level and that is why it was selected to be included in the multivariate models.

Association between oral health literacy and oral health knowledge

In agreement with all the previous studies (Table 3), this study reported significant

associations, at the bivariate level, between oral health knowledge and oral health literacy

(measured using the three oral health literacy instruments). This association remained after

adjusting for other variables in the multivariate level of analysis for the OHLI and REALD-30, but

not CCOHLI. It has to be emphasized that this agreement was observed despite the

heterogeneity in assessing the oral health knowledge. In this project, we utilized a previously

201

validated test to assess the oral health knowledge72, which assesses patient knowledge of dental

terms that might be encountered in the dental clinic and/or dental educational materials, with

groups of pictures.

The association between oral health literacy and oral health knowledge can be explained in

different ways. Oral health literacy can be viewed as a prerequisite to obtain oral health

knowledge or as an outcome of oral health knowledge. In other words, those with increased

oral health-related vocabulary and conceptual knowledge about dental disease would find it

easier to read and comprehend the materials than those with lower dental knowledge and

literacy levels, or those with adequate oral health literacy would be able to navigate and obtain

oral health knowledge.

Association between oral health literacy and caries experience

This is one of the first studies to evaluate the association between oral health literacy and

caries experience as an oral health outcome in adult patients. Only one previous publication

evaluated the association between caregiver’s oral health literacy level and children’s caries

experience80. The caries experience was assessed in our study by using the DMFT index, with D,

M and F representing the decayed, missed (due to caries) and filled (due to caries). One of the

limitations of the study was that examination was done by undergraduate students (under

supervision) and was not standardized. All efforts were tried to avoid overestimating the DMFT

score. In this study we followed the approach of the Australian report 90 and extended the

missing teeth to include teeth missing due to caries and periodontal disease, due to the

difficulty in differentiating between them. All efforts were exerted to exclude teeth missing due

to other reasons (trauma, congenitally missing and orthodontic extraction) by considering the

patient age, location of missing tooth/teeth, previous dental history and general oral health

status.

On average, our participants had more teeth with untreated caries, more missing teeth,

fewer filled teeth and higher DMFT score in comparison to the data reported by the Canadian

adults in the CHMS96 (DT: 4.29 VS. 0.58, FT: 6.8 vs. 7.95, MT: 3.55 vs. 2.14 and DMFT: 14.65 VS.

10.67). Similarly, on average, our participants had higher DT/DMFT, lower FT/DMFT and

comparable MT/DMFT in comparison to CHMS data (29.8 vs. 5.5%, 47.9 vs. 74.4% and 22.21 vs.

20.1%, respectively). These differences are expected between our sample with most of the

202

participants seeking dental treatment to their dental problems and the population-based study.

No significant associations were found between the DMFT and any of the oral health literacy

instruments. On the other hand, significant associations were identified between some of the

components of the DMFT and oral health literacy, particularly, between DT/DMFT% and both

CCOHLI and REALD-30 and between FT/DMFT% and both OHLI and REALD-30. In general,

participants with low oral health literacy level had higher DT/DMFT% and lower FT/DMFT% in

comparison to participants with adequate oral health literacy level, but some of these

differences failed to reach the statistically significant level for some instruments.

Due to the diversity of the variables that can be used to summarize DMFT, we were not able

to include all of them in the multivariate analysis. The following variables were used in the

multivariate analysis to summarize the D, M and F components: 1) presence of any untreated

caries; 2) number of missing teeth (MT) and 3) FT/DMFT ratio. The presence of any untreated

caries (yes/no) was selected instead of DT or DT/DMFT because the presence of untreated

caries is a more important outcome than the severity and the extent of caries. The FT/DMFT

ratio was selected instead of the FT because of the interest in the percentage of the filling to the

total DMFT, not the number of fillings. We hypothesized that participants with an adequate oral

health literacy level would have a higher FT/DMFT ratio than participants with low and

inadequate oral health literacy, reflecting better access to care and better decision making. On

the other hand, MT was selected, not MT/DMFT ratio, because we hypothesized that the

number of missing teeth would increase in participants with low or inadequate oral health

literacy reflecting an increase in the severity of the disease and/or poor treatment decision

making.

Multivariate analysis revealed a significant association between the presence of untreated

caries and oral health literacy level (measured using CCOHLI and OHLI), although there was no

significant association at the bivariate level. The odds of having marginal or inadequate oral

health literacy for participants with any untreated caries compared to those with no untreated

caries increased by 4.3 and 8.1 times for CCOHLI and OHLI respectively, after adjusting for the

other variables in the model. In contrast, no significant association was observed between MT or

FT/DMFT and oral health literacy at the multivariate level.

203

Association between oral health literacy and periodontal disease

We based our assessment of the periodontal condition on the periodontal charting made by

the undergraduate students as part of their periodontal examination. Most of the students

recorded the periodontal pocket depths on all the teeth but failed to indicate the amount of the

recession in their charting. Hence, we were not able to calculate the amount of attachment loss,

which hindered our ability to use the various definitions for periodontal disease that were used

previously in epidemiological studies. In this study, we used the definition proposed by the U.S.

National Center for Health Statistics90 which defines periodontal disease as at least one

periodontal pocket with a probing depth of 4 mm or more and a loss of attachment at the same

site of 3 mm or more. Based on this definition, only 8 patients (6.7%) were identified as not

having periodontal disease and no significant association was identified between periodontal

condition and oral health literacy at the bivariate level. It has to be emphasized that with such

distribution, our findings should be interpreted cautiously. The analyses were repeated using

various cut-off points to define the periodontal disease (data are not presented) and no

significant association was identified.

In contrast to our findings, a recent study evaluated the association between oral health

literacy (measured using REALD-30) and periodontal status and reported a significant

association at the bivariate level and after controlling for smoking, race and dental insurance98.

It has to be stressed that in this study, periodontal examination was standardized and clinical

attachment loss was taken into consideration.

204

Figure 5: Conceptual framework for association between oral health literacy and different factors and outcomes

205

Part 3:

Several previous studies focused on evaluating the performance of screening questions in

detecting patients with inadequate health literacy83;99;100 in different medical settings. Due to the

differences between medical and dental settings and the literacy skills required for each of

them, the questions were slightly modified and their performance was tested against different

oral health literacy instruments.

The highest AUROC were achieved with OHLI as a comparison standard, with AUROC

significantly above the null value (0.5) for all the screening questions. In contrast, only two

questions had AUROC significantly higher than the null value for the REALD-30 and only one

question for the CCOHLI. One screening question, "How often do you have problem learning

about your medical/dental condition because of difficulty understanding written information?"

was able to identify patients with limited oral health literacy measured using the three different

oral health literacy instruments. These differences in the performance of the screening

questions against different oral health literacy tests in this study may reflect differences in the

skills and capacities measured by each instrument. Similarly, different results were reported in

the medical literature when different health literacy instruments were used or different

populations were studied83;99;100.

The areas under the ROC curve reported in this study were lower in comparison to previous

studies in the medical field83;99;100, which may relate to the differences between the medical and

dental settings and the fact that the questions were developed for the medical environment.

Future research can be directed to developing other questions that focus on the skills required

for the dental setting.

Selecting the optimal cutoff point for a screening test depends on several factors, including

test accuracy, prevalence of the disease, costs of testing and consequences of a false-positive or

false-negative test result83. Ideally, the best cutoff point for a screening test is the one with the

highest sensitivity and specificity. Unfortunately, it is difficult to find a test that will provide both

high sensitivity and specificity. Typically, a trade off in sensitivity, specificity or both must be

made. If the aim of the test is to identify most of the patients with limited oral health literacy, a

cutoff point with high sensitivity and low negative likelihood ratio should be chosen. However, if

the aim of the test is to correctly identify the patient with limited oral health literacy, a cutoff

point with high specificity and positive likelihood ratio should be selected. In this study, the

206

cutoff points that give the highest sum of sensitivity and specificity were selected. It has to be

emphasized that the implication of the cutoff point might vary with the change in the

prevalence of the limited oral health literacy. To give an example, a response “Never” to the

question about the problem in learning about the dental condition, with OHLI as standard test

and prevalence of inadequate or marginal oral health literacy of 31%, will give a post-test

probability for positive test results of 40%, Decreasing the prevalence to 10% will decrease the

post-test probability for positive test results to 15%.

207

Part 4:

Interpersonal Processes of Care Questionnaire (IPC) and the pattern of communication

in the undergraduate clinic

There is a growing body of evidence that both interpersonal process of care and technical

process of care contribute to the overall quality of health care89;101;101.

The Interpersonal Process of Care (IPC) incorporates different socio-psychological aspects of

the clinical interaction, including the patient-provider communication, which can be affected by

several factors, including the patient’s health literacy level91. In this study, we focused on the

association between the quality of the prior dentist-patient communication and the oral health

literacy. The quality of dentist-patient communication was assessed using a previously validated

medical instrument89. The wording of the questions was slightly modified to fit the dental

context and evaluated by experts in the field of public health and preventive and community

dentistry.

On average, the scores of the IPC domains were in the favorable range, except for the

decision-making domain. The domains of the explanation of self-care, empowerment and

decision-making showed high percentages of participants reporting poor communication; thus,

these represent important areas of future improvement. Specifically, fifty to sixty percent of the

patients reported that their dentists rarely or never gave them written oral hygiene instructions,

motivated them to modify their daily activity to improve their oral health, or asked if they have

any problems performing oral hygiene measures. Based on the participants’ previous encounter,

it seems that dentists exerted effort in listening to the patient and explaining the disease and

the dental procedure with little focus on the explanation of self-care, motivation and eliminating

possible barriers encountered by the patients. This reflects a tendency toward focusing on the

technical and not the preventive aspect of the dental management. The questionnaire about the

pattern of communication in the undergraduate clinic revealed similar findings, with about 39%

of the students failing to provide adequate information to the patient about their dental

diseases and how to prevent them, and only 54% of the students providing oral hygiene

instructions to their patients during their initial visit. This could be attributed to the slow pace at

the academic setting and limited experience of the students, which might preclude the

exchange of information during the initial visit. The effect of the experience on the

communication pattern was obvious in this study, with better performance of the 4th year

208

students in comparison to 3rd year students. These deficiencies in the communication skills

among dentists should direct the focus of future research and efforts toward integrating more

communication-related topics in dental curricula. Unfortunately, despite the previous

recommendations, training in communicative skills is rarely offered at dental schools102.

Association between IPC domains and socio-demographics, dental attendance, oral


The quality of physician-patient communication has received reasonable attention in the

medical literature. Successful provider-patient interaction was linked to patient dental

knowledge, satisfaction, attendance pattern and compliance/adherence91. Several factors were

suggested in different models to affect the patient-provider encounter, including: patient’s prior

experience of care; patient’s objectives and expectations; nature and number of patient’s

concerns; provider’s expectations; provider’s prior knowledge of patient’s concern;

characteristics of provider’s practice setting; and patient and provider personality91.

On the other hand, most of the previous studies in the dental field focused on evaluating

the quality and readability of written instruction with limited attention directed toward the

quality of the verbal interaction in spite of the fact that verbal communication is the

predominant mode of interaction between the dentist and the patient at the dental office.

Our study is one of the early studies that explored the association between the dentist-

patient communication experience and different predictors and outcomes. Different patterns of

associations were observed among different IPC domains, which might reflect some diversity

among the domains. An interesting finding that merits further investigation is the association

between self-reported oral health status and the IPC explanatory domains. These associations

remained significant at the multivariate analysis for two of the IPC domains. Time of last dental

visit and reason for the visit were both associated with the general clarity domain at bivariate

and multivariate levels. Participants who reported that their last dental visit was more than 12

months ago were 70% less likely to report poor quality of communication in comparison to

those who visited the dentist within the last 12 months. Although the direction of association is

against expectation, it might be explained by the poor recall rate after 12 months and/or lower

treatment needs which was reflected in less frequent dental visits. On the other hand,

participants who reported emergency as the reason for their last dental visit were about 3 times

209

more likely to report poor communication with their dentist in the general clarity domain, which

might reflect the overwhelming nature of the emergency visit. Unfortunately, neither a plausible

explanation is available for some of these relationships nor is a previous study available in the

dental literature to be compared to our results.

Association between IPC domains and oral health literacy

To our best knowledge, the association between the oral health literacy and the quality of

the previous dentist-patient communication was not reported previously. Oral health literacy

was assessed using three different instruments, which assess word recognition, reading

comprehension, numeracy, communication and critiquing skills.

No association or correlation was observed between the word recognition test score and

any of the IPC domains. In contrast, participants who had low or marginal dental word

recognition ability reported worse communication in the domain of general clarity. However,

this bivariate association disappeared at the multivariate analysis. Participants who had

difficulties in recognizing and reading dental-related words were challenged by the difficulties of

the dental term used by their dentists, not by the speed at which information was transmitted

to them. Kripalani et al.103 reported a similar association between the health literacy among

hospitalized patients, measured using a medical word recognition test (REALM), and the IPC

general clarity domain.

In regard to the association between the reading comprehension and numeracy skills,

measured using OHLI, and the quality of the interpersonal process of care, no difference was

observed between the reading section scores among participants who reported good or poor

communication with the dentist for any of the domains. Nevertheless, significantly lower

numeracy scores, on average, were observed among the participants who reported poor quality

of communication for the elicitation and responsiveness, explanation of the condition and

empowerment domains. These differences in the mean scores ranged between 1–3 points,

which might not reflect any clinical significance and were not reflected in the association

between the OHLI level (adequate vs. marginal or inadequate) and the IPC domain level (poor

vs. good). A previous study reported dissimilar findings among outpatient diabetic patients.

Schillinger et al. 80 found that patients with inadequate functional health literacy; measured

using a short-form of TOFHLA, reported significantly worse communication on the general

210

clarity, explanations of processes of care, and explanations of condition domains, which might

reflect some differences between the dental and medical settings. Management of chronic

disease, such as diabetes, necessitates a different pattern of communication by the provider,

which might involve technical terms and require numeracy skills to be comprehended.

CCOHLI level was significantly associated with most IPC domains. The communicative oral

health literacy section showed significant negative weak correlations with all the IPC domains

except general clarity. Similarly, significantly lower communicative oral health literacy scores, on

average, were observed among the participants who reported poor communication with their

dentist for 5 of the IPC domains. In contrast to the communicative section, critical oral health

literacy was associated with fewer IPC domains. These associations reflect the similarity

between the IPC and CCOHLI, since both of them address the communication process between

the provider and the patient, with the former assessing the quality of the provider-patient

communication and the latter assessing the participant’s perception of his/her communication

skills.

Patients with limited health literacy have limitations in reading and comprehending written

health information, as well as in processing oral communication104;105. In our study, participants

with poor oral health literacy were more likely to report poor communication with their dentist

and to be under-informed and confused during their communication with their dentists.

It is not clear how IPC domains are associated with different outcomes and predictors,

including oral health literacy. Answering this research question will require more complex

modeling and analytical techniques. It is well known that the communication process between

the dentist and the patient is a dynamic process that involves the participation of both parties

and any discordance between them might affect the process. Deficiencies in the communication

process can be due to deficiencies on the part of the patients and/or the provider.

Patients with low oral health literacy have limited dental vocabulary and knowledge65;72;78-81

that can result in poor dentist-patient communication, especially when combined with a

dentist’s use of specific technical and dental terms. A previous study reported an association

between limited oral health literacy and low perception of self-efficacy62, which may influence

patient’s behavior in the clinical encounter. A recent publication addresses the other side of the

communication experience, the communication behavior of the patient, and found that

participants with adequate communicative health literacy were more likely to employ an

211

interactive communication style and challenge their physician by asking questions and asking for

clarification106;107. It has to be emphasized that the communicative health literacy was assessed

with a similar questionnaire to the one used in our study.

On the other hand, providers can contribute to the deficiency by simply not communicating

with their patients or being partially effective or ineffective during their communication80. A

study in the medical field reported that physicians had a tendency to overestimate the health

literacy of their patients, which might be reflected in their communication with their patients107.

In addition, providers might have a tendency to alter and simplify the communication process

for patients with limited oral health literacy, which might lead to superficial communication and

avoidance of in depth explanation during the interaction with these patients. Another factor

that should be considered in the communication process is that patients with limited oral health

literacy may need more time to absorb the information delivered to them, which can be a

barrier to properly communicating with them. Unfortunately, it is difficult to charge the patient

for the extra time spent with them because such a fee is not available in most of the fee guides

and will not be accepted by third-part payers.

Dentist-patient communication has been recognized as one of the important topics to be

integrated into the dental curriculum. Unfortunately, despite previous recommendations,

training in communicative skills is rarely offered at dental schools102.

212

Strengths

&

Limitations

213

Strengths of the study:

o To our knowledge, this is the first attempt to develop and validate an instrument to assess

communicative and critical oral health literacy. This instrument, in addition to other

functional oral health literacy instruments (reading comprehension and word recognition

instruments), allows the assessment of all levels of oral health literacy (functional,

communicative and critical) as suggested by Nutbeam7 and helps in identifying different

barriers that might contribute to participant oral health literacy inadequacy.

o This is one of the few projects that encompasses all these variables in one study using the

same group of patients. This approach helped us in understanding the associations

between oral health literacy and its potential predictors and oral health outcomes as

suggested by our conceptual framework (Figure 5). Most of the previous studies selected a

limited number of predictors and/or outcomes and studied them under one study.

Unfortunately, this approach might limit the vision to these particular predictors and/or

outcomes and burden our ability to infer association between different variables used in

different studies due to the heterogeneity in the population and methodology among

studies.

o This is one of the first studies to validate a set of brief and easy-to-use screening questions

to identify patients with inadequate oral health literacy. These OHL screening questions will

be useful tools in busy dental practices in comparison to the various oral health literacy

tests, which might be time-consuming and not practical in busy clinical settings.

o It is also one of the first studies to evaluate the association between the quality of previous

dentist-patient communication and oral health literacy.

214

Limitations, general observations and future directions:

o The critical section of CCOHLI focused on the skills required to act individually to exert

control over different health-related life events and situations, but it does not cover the

broader skills required to take social and political actions at the community level as

suggested in Nutbeam’s definition of critical health literacy7.

o All the questionnaires and tests used in this study were in English. Thus, a certain level of

English proficiency is required to complete them. The readability level of these

questionnaires and tests was kept to the lowest possible level. Different versions of these

instruments and questionnaires are needed in other languages to cover participants who

cannot read, speak and understand English well.

All efforts were made to identify the participants who might experience some difficulties in

filling out the questionnaires and test. First, participants were asked during the introduction

to the study if they can read, speak and understand English well. Only those who answered

yes to this question were asked to participate in the study. In addition, the primary

investigator was able to identify some of these patients who might face difficulties in

completing the form during the introduction. Some of the participants (less than 10)

recognized that the questionnaires might be difficult for them after reading the consent

form and decided not to participate.

o The results of this study cannot be generalized to the entire population because the

instrument testing was conducted on a convenience sample. Such a convenience sample

might lead to skewed distribution of the participants among some of the variables (e.g.

education). Future research should be conducted on a probability community-based

sample that represents a larger and more diverse population, preferably not regular users

of the dental care system.

o The ranges or categories for some of the items (e.g. annual income) in Appendix 3 were

arbitrary selected. Some of the findings in the study might be changed if different choices

or ranges were provided.

o The limited sample size might affect the distribution of each variable and, subsequently,

might have led to insufficient variability to detect a significant difference. The sample size

was selected based on a sample size calculation demonstrated previously for the multiple

linear regression. The sample size was increased by 20% to accommodate any attrition in

215

the sample. Most of our participants completed all the required tests and questionnaires

and their data were available for the bivariate analysis. We experienced some difficulty in

tracking some of the patients who rescheduled their oral diagnosis appointments, which

resulted in attrition in the data. Unfortunately, some of the patients were deemed not to

be suitable for the undergraduate clinic and were dismissed due to complex medical

condition after completing most of the questionnaires and tests and before completing the

full dental and periodontal charting. The data of these patients were used for the bivariate

but not the multivariate analyses. Another group of patients completed their dental

examination at the oral diagnosis visit but did not receive a full periodontal charting for a

variety of reasons, including mild periodontal involvement, lack of interest in continuing

treatment at the school or referral to another graduate clinic.

o Non-parametric statistical techniques were used to analyze the data in this study due to

skewness observed in some of the variable distributions. Unfortunately, all attempts to

transform the data and use parametric techniques failed. This forced us to use the oral

health literacy level (dichotomized) in logistic regression instead of the actual oral health

literacy score in multiple linear regression. This approach is never without a cost since non-

parametric statistics might lead to loss of some of the information and a decrease in power.

In addition, the selection of the cut-off points was arbitrary and might not be suitable for

other populations.

o All clinical examinations were completed by undergraduate students under supervision of

clinical instructors. Unfortunately, standardization among this large number of students

was not feasible. In addition, an alternative approach of recruiting examiners to complete

all examinations was not possible because of the financial and time constraints.

o The OHLI requires about 20 minutes to administer, making it more appropriate as a

research tool rather than a clinical tool. Nevertheless, future research should be directed to

develop an even shorter format of the test to make it more practical for clinical settings.

o OHLI consists of items that test literacy skills needed in the dental clinic settings only.

Future research should include other literacy skills encountered by the patient in different

settings (e.g., at home or at the drug store).

o It is clear that CCOHLI, OHIP-14 and most of the questionnaires used in this study are self-

reporting. The findings that resulted from these questionnaires and tests should be

216

interpreted within the inherent limitations of the self-reported questionnaire. It is well

known that patient self-reports are heavily influenced by personal beliefs, cultural

background, and social, educational and environmental factors108. Results might be

affected by participants’ recall errors, instability of their opinions, misunderstanding of

questions, and tendency to report socially desirable answers109;110. An interesting finding

worth further investigation is that the CCOHLI was associated with most of the self-

reported variables (e.g., self-reported oral health status, oral health behavior and oral

health-related quality of life).

o The validity of using self-reported outcomes as a measure of oral health literacy has been

critiqued on the basis that the relationship between self-reported and clinically determined

oral health is complex and there is some discrepancy between them108.

o The generalizability of the findings from this project might be limited by the cross-sectional

nature of the study. Peek et al.111 reported that oral health status is dynamic and varied

across time. It will be interesting to compare the changes in oral health status longitudinally

among patients with different oral health literacy levels.

o The relationships between oral health literacy and the different variables were analyzed

using different statistical methods to allow the interpretation of the data from different

perspectives. It has to be emphasized that the data should be interpreted in light of the

limitations of the statistical technique used. For example, the significance test of the

correlation coefficient is a function of the sample size (i.e., with large sample size, even a

very weak correlation can be significant). In addition, the statistical analysis using the actual

scores of the oral health literacy test might be deceptive. For example, a difference of 5

points in the average OHLI score might be statistically significant but might not represent

any clinical significance. Finally, dichotomizing the continuous variables might lead to loss

of some important information and is dependent on the cut-off point selected.

o It has to be emphasized that the implication of the cutoff point for the screening

questionnaire might vary with the change in the prevalence of the limited oral health

literacy in the population. This should be in mind when using the screening questions in

different populations.

217

o In this study, we focused on the association between oral health literacy and quality of the

communication provided by the dentist. Future research should be directed toward the

other face of the communication process, which is the quality of the patient participation.

o Due to current deficiencies in integrating communication skills in the dental curricula,

future research and organized efforts should be directed toward addressing these

deficiencies.

218

Summary

&

Conclusions

219

Summary and Conclusions

In summary, initial testing of the CCOHLI showed it to be a valid and reliable instrument to

evaluate the communicative and critical oral health literacy of adult patients. In addition, the

predictive and construct validity of the previously developed and validated OHLI was confirmed

in this study. Indeed, this study shed light on the association between oral health literacy and

different determinants and/or outcomes. In fact, the variability of the relationships among

different oral health literacy instruments emphasizes the fact that these instruments measure

different skills and that some of the skills might be needed for certain tasks but not for others,

which supports the model proposed by Nutbeam7 about the different health literacy skills.

The conceptual framework (Figure 5) suggested in this project can be a base for future

research to be investigated and validated among populations known to be at greater risk of

limited oral health literacy.

Furthermore, the validity of a set of questions as a quick tool to identify patients with limited

oral health literacy was established in this study. These screening questions can provide a rapid

and inexpensive way to identify patients with limited oral health literacy in a busy clinical setting

or to conduct large-scale studies. When identified, various oral health literacy tests can be

administered to assess patients’ oral health literacy skills and customize the best approach to

improve their literacy skills or to communicate with them about their oral health.

One of the focuses of this study was to assess and determine different factors and outcomes

associated with limited oral health literacy. Future work should be directed to explore different

solutions to help improve patient oral health literacy. Unfortunately, this topic has received

limited attention in the dental and medical literature. One of the areas that require special

attention is dentist-patient communication, which was recognized in this study to be influenced

by oral health literacy. Several recommendations were suggested to improve the

communication with patients who have limited health literacy, including minimizing the amount

of medical/dental terminology used, encouraging patient participation by asking questions,

limiting the amount of information during each visit, using pictures and other illustrations,

augmenting verbal communication with written materials, and confirming patient

understanding via the "show-me" or "teach-back" method46;112-115. Future research needs to

evaluate the efficacy and effectiveness of different communication methods to address patients

with limited oral health literacy skills.

220

Implications for practitioners, researchers and policy makers

For practitioners:

o Practitioners should be more aware of oral health literacy as a potential barrier

during dental treatment. They have to be able to identify patients with limited

oral health literacy, approach them using suitable educational materials and

modify their communication techniques when dealing with them. Thus,

screening questions that have been tested in this project might be a useful tool

for practitioners in a busy dental practice, followed by the full oral health

literacy instruments to identify the source of the inadequacy among the

patients who were identified with limited oral health literacy using the

screening questions.

For researchers:

o The results of this project can work as a foundation that researchers can build-

on and proceed toward a better understanding of the association between oral

health literacy and different oral health outcomes and behaviors on large

community-based samples. These community-based studies will help in

estimating the prevalence of limited oral health literacy, in order to

appropriately design and evaluate different educational materials and

community-based health promotion programs.

o Oral health literacy screening questions and shortened versions of the oral

health literacy instruments can be useful tools for researchers in large-scale

surveys where the use of the full instrument might not be feasible due to time

constraint.

o Till now, it is not known whether separate instruments, other than the

instruments developed for the field of medicine, are needed for the dental field.

Future research should be directed toward using both types of instrument on

the same participants and evaluating the association between them and oral

health outcomes and behaviors.

o More work should be directed to the field of patient-dentist communication in

order to evaluate different communication methods and come up with

recommendations.

221

For dental educators and policy makers:

o Dental educators should devote more effort toward incorporating oral heath

literacy as an important topic in the dental curriculum. Similarly, more emphasis

should be given to patient-dentist communication as an integral part of the

relationship between patients and dentists. Dental curricula should incorporate

more topics about patient-dentist communication and it should be emphasized

as an integral part of the treatment process.

o Although our current knowledge is not enough for policy makers to make

changes, they can still work with researchers, educators and health authorities

to develop strategies for research in the field. For example, health surveys can

be redesigned to capture more information about the association between oral

health literacy and different oral health and behavioral outcomes.

222

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232

Appendices

233

Appendix I

235

Appendix II

236

Information Sheet and Consent Form

Title of the Project:

Association between Oral Health Literacy and Patient-Centred and

Clinical Outcomes

Funded by Dental Research Institute at the Faculty of Dentistry, University of Toronto

This study will be conducted by Dr. Dania Sabbahi, as a part of her PhD project at the Faculty

of Dentistry, University of Toronto. Dr. Sabbahi is working under the supervision of Prof. Hardy

Limeback, Professor in the Discipline of Preventive Dentistry at the University of Toronto. One

Hundred and sixty (160) adult patients are expected to be part of this study.

Aims of the Study

1. To develop a test to measure oral health literacy. Oral health literacy is defined as the

ability of the person to find, read and understand information about dentistry.

2. To see how this test compares to other tests used in dentistry and medicine.

3. To see how well the screening questions are in measuring oral health literacy.

4. To see if the test can predict who has better dental health.

5. To see what factors might affect the oral health literacy.

Study Procedures

Participants in this study are expected to attend two or three (2 or 3) visits at the Faculty of

Dentistry.

The first and second visits:

In those visits, the participant will be asked to complete:

Three (3) questionnaires about their personal information, oral health status, oral health

behaviors and their communication with their dentist.

Four (4) different oral health and health literacy tests.

Dental Knowledge test.

FACULTY OF DENTISTRY, UNIVERSITY OF TORONTO

124 Edward Street, Toronto, Ontario M5G 1G6

CANAD A

237

A test that will measure the effect of the patients’ dental health on the quality of life.

The third visit (approximately two weeks after the first visit):

Thirty-two (32) participants in this study will be selected randomly to attend this third visit.

The selected participants will be asked again to complete one of the tests that they have filled in

their first visit (Critical and Communicative Oral Health Literacy test).

In addition, the study investigators will need access to the participant dental and medical

records at the Faculty of Dentistry, University of Toronto. She might also need to contact the

participants by phone to schedule appointments if needed.

Length of the Study

The first visit will take about 5-10 minutes; the second visit will take about 30-35 minutes,

while the third one will take about two minutes.

Confidentiality of Study Records

The information regarding participation in this study will be kept confidential, and all forms

used in the study will be stored in a locked filing cabinet at the Faculty of Dentistry, University of

Toronto. All electronic data will be saved on the personal laptop computer of the principal

investigator. Only Dr. Dania Sabbahi; and her supervisor, Prof. Hardy Limeback, will have access

to these forms and electronic data. All the study records will be maintained by the principal

investigator for a period of three (3) years; and will be destroyed thereafter.

The results of this study may be presented at professional and scientific conferences; and/or

published in scientific journals. The results will not contain any names; or any identification of

the participants.

The test results will be available to the participant after completing the study upon request.

Risks

There are no risks involved in this study.

238

Benefits

These tests will help dentists to see how people understand dental information. This study

will help us to understand more about the factors associated with low oral health literacy. This

will help dentists to make better choices for the benefit of their patients. Each participant will be

given $18 for participation. This may be taken in cash or as credit toward dental treatment at

the Faculty of Dentistry, University of Toronto.

Right to Withdraw from the Study

Participation in this study is voluntary. Participants may withdraw from the study at any

time; with no effect on their current or future care at the Faculty of Dentistry clinics.

Questions Regarding the Study

If you have any questions about this study; please contact the principal investigator, Dr.

Dania Sabbahi, via e-mail ([email protected]) or by telephone (416-979-4900 ext. 4597

or voice mail 3036), or contact her supervisor, Prof. Hardy Limeback, via e-mail

([email protected] ) or telephone (416-979-4929 ext. 4461).

I have read, or had explained to me, the information about this study. I have had the

opportunity to ask questions and have had them answered fully. I have received an information

sheet about the study for future reference.

I ,___________________________________, agree to participate in the above study.

Name (please PRINT)

_____________________________________ __________________

Signature Date

mailto:[email protected]

mailto:[email protected]

239

Appendix III

240

STUDY TILTLE:

Association between Oral Health Literacy Patient-Centred and

Clinical Outcomes

Name: _____________________________

Date of Birth (DD/MM/YYYY):

_________/_________/___________

FACULTY OF DENTISTRY, UNIVERSITY

OF TORONTO 124 EDWARD STREET, TORONTO,

ONTARIO M5G 1G6

Identification number: ______________

Date (DD/MM/YYYY):

________/_________/___________

241

Please answer/choose the most appropriate response: Q1 Gender a) Male b) Female Q2 Native Language a) English b) Other (please specify:____________________) Q3 How long have you been in Canada? a) Less than 5 years b) 5-10 years c) More than 10 years Q4 Where did you grow up? (_______________________) Q5 What is the highest level of school you have completed? a) Postgraduate education b) College degree c) Some college d) High school or less Q6 What is your household income? a) less than 20,000$ b) 20,000-39,999$ c) 40,000-59,000$ d) 60,000- 79,000$ e) More than 80,000$ Q7 Why have you decide to be a patient at the Faculty of Dentistry? a) Referred by my dentist b) To treat a dental emergency c) To treat my dental problems d) Just for check-up Q8 Where do you normally obtain dental information from? a) I have never looked for dental information before b) From my dentist c) From other health professionals (family doctor, pharmacist … etc.) d) From media (i.e. TV, Radio) or newspapers e) Internet f) Other (please specify:_________________________)

242

Q9 In case of any dental problem, whom would you ask for advice? a) Family b) Friends c) Family physician d) Dental health professional (i.e. Dentist, Dental hygienist, Dental assistant) e) I figure it out my self f) Other (please specify:_________________________) Q10 When was your last dental visit? a) During the last 12 months b) More than 12 months ago c) Never (Please skip questions 11 and 12 and go to question 13) Q11 What was the reason for your last dental visit? a) For check-up b) For emergency (e.g. pain) c) To receive scheduled dental treatment d) Consultation Q12 Do you visit the dentist regularly for check-up? a) Yes b) No Q13 Do you own a tooth brush? a) Yes b) No Q14 How many times do you brush your teeth in a day? a) Once b) Twice c) More than twice d) Never Q15 Do you floss between your teeth? a) Yes

b) Sometimes c) No Q16 How do you intend to pay for your dental treatment? a) Dental insurance from work b) Governmental assistant c) I’ll pay it myself “No insurance” d) Other (please specify: ________________________)

243

Q17 How do you rate your oral health? a) Excellent b) Very good c) Good d) Fair e) Poor

244

Appendix IV

245

Health literacy screening questions

Listed below are some questions about health literacy. Please indicate whether you feel that you ALWAYS (1), OFTEN (2), SOMETIMES (3), OCCASSIONALLY (4) or NEVER (5) have difficulty to understand health information. Please circle your answer for each question:

Questions

Alw

ays

Oft

en

Som

etim

es

Occ

asio

nal

ly

Nev

er

1. How often do you have problem learning about your medical/dental condition because of difficulty understanding written information?

1 2 3 4 5

2. How confident are you filling out medical/dental forms by yourself?

1 2 3 4 5

3. How confident do you feel you are able to follow the instructions on the label of a medication bottle?

1 2 3 4 5

4. How often do you have someone (like family member, friend, hospital/clinic worker or caregiver) helps you read hospital material?

1 2 3 4 5

246

Appendix V

247

Interpersonal Processes of Care in Diverse Populations Questionnaire

(IPC)

Please answer the following question based on your previous interaction with your

dentist before attending the Faculty of Dentistry Clinics. (Please circle one number

against each statement).

Scale Item

Alw

ays

Oft

en

Som

etim

es

Rar

ely

Nev

er

General clarity 1. How often did your dentist use medical/dental words that you did not understand?

1 2 3 4 5

2. How often did you have trouble understanding your dentist because he/she spoke too fast?

1 2 3 4 5

Elicitation of and

responsiveness to

patient problems,

concerns and

expectations

3. How often did your dentist give you enough time to say what you thought was important?

1 2 3 4 5

4. How often did your dentist listen carefully to what you had to say?

1 2 3 4 5

Explanations of

condition

5. How often did your dentist give you enough information about your oral health problems?

1 2 3 4 5

6. How often did your dentist make sure you understood your oral health problems?

1 2 3 4 5

Explanations of

processes of care

7. How often did your dentist explain why the dental procedure was being done?

1 2 3 4 5

8. How often did your dentist explain how the dental procedure is done?

1 2 3 4 5

248

9. How often did you feel confused about what was going on with your dental care because your dentist did not explain things well?

1 2 3 4 5

Explanations of self-

care

10. How often did your dentist tell you what you could do to take care of your oral hygiene at home?

1 2 3 4 5

11. How often did your dentist tell you how to pay attention to your symptoms and when to call him/her?

1 2 3 4 5

12. How often did your dentist explain clearly or demonstrate to you how to perform oral hygiene procedures?

1 2 3 4 5

13. How often did your dentist give you written instructions about how to perform oral hygiene procedures?

1 2 3 4 5

Empowerment 14. How often did your dentist make you feel that performing your oral hygiene practices would make a difference in your oral health?

1 2 3 4 5

15. How often did your dentist make you feel that your everyday activities such as your diet would make a difference in your oral health?

1 2 3 4 5

Decision-making

around desire and

ability to comply

16. How often did your dentist ask if you might have any problems doing the recommended oral hygiene measures?

1 2 3 4 5

17. How often did your dentist understand the kinds of problems you might have in doing the recommended oral hygiene measures?

1 2 3 4 5

249

Appendix VI

250

Questions of OHIP-14

Listed below are some questions about the impact of oral health and quality of life.

Please indicate in the last 12 months how often you felt any of the listed problems. You

may NEVER (0), HARDLY EVER (1), OCCASIONALLY (2), FAIRLY OFTEN (3) or VERY OFTEN

(4) felt any of the listed problems . Please circle your answer for each question

Dimension

Question

Ver

y o

ften

Fair

ly o

ften

Occ

asio

nal

ly

Har

dly

eve

r

Nev

er

Functional

Have you had trouble pronouncing any words because of problems with limitation your teeth, mouth or dentures?

4 3 2 1 0

Have you felt that your sense of taste has worsened because of problems with your teeth, mouth or dentures?

4 3 2 1 0

Physical pain

Have you had painful aching in your mouth?

4 3 2 1 0

Have you found it uncomfortable to eat any foods because of problems with your teeth, mouth or dentures?

4 3 2 1 0

Psychological discomfort

Have you been self-conscious because of your teeth, mouth or dentures?

4 3 2 1 0

Have you felt tense because of problems with your teeth, mouth or dentures?

4 3 2 1 0

Physical disability

Has your diet been unsatisfactory because of problems with your teeth, mouth or dentures?

4 3 2 1 0

Have you had to interrupt meals because of problems with your teeth, mouth or dentures?

4 3 2 1 0

Psychological disability

Have you found it difficult to relax because of problems with your teeth, mouth or dentures?

4 3 2 1 0

251

Have you been a bit embarrassed because of problems with your teeth, mouth or dentures?

4 3 2 1 0

Social disability

Have you been a bit irritable with other people because of problems with your teeth, mouth or dentures?

4 3 2 1 0

Have you had difficulty doing your usual jobs because of problems with your teeth, mouth or dentures?

4 3 2 1 0

Handicap

Have you felt that life in general was less satisfying because of problems with your teeth, mouth or dentures?

4 3 2 1 0

Have you been totally unable to function because of problems with your teeth, mouth or dentures

4 3 2 1 0

252

Appendix VII

254

Instructions:

In this part, you will be shown some pictures on the right side of the

pages, and on each picture there are labels pointing to certain parts of the

picture.

On the left of the pages, there are lists of numbered words. Each picture

has its own word list. Choose the word from the word list that describes the

part that is labeled. Put the word number in the label (at the end of each

line).

The number of words in each list might be more than the number of

labels. Please choose only one word for each label.

255

1. Caries

2. Molars

3. Uvula

4. Composite

5. Incisors

6. Frenum

7. Dorsal side of the tongue

8. Gingiva

9. Amalgam

10. Denture

11. Palate

12. Lips

1. Caries

2. Physiologic pigmentation

3. Molars

4. Pre-molars

5. Internal bleeding

6. Composite

7. Calculus

8. Brushing

9. Floor of the mouth

10. Amalgam

11. Gingival bleeding

256

1. Caries

2. Molars

3. Uvula

4. Composite

5. Incisors

6. Amalgam

7. Denture

8. Palate

1. Brush

2. Interdental brush

3. Dental floss

4. Mouthwash

5. Fluoride application

6. Brackets

257

Appendix VIII

258

Instructions:

In this part, you will be given two passages talking about some dental

problems and their solutions that you or anybody might see in the dental

clinics or in dental pamphlets.

In each passage, there is a missing word (indicated by a blank line).

There are four (4) possible words listed and one fits well in the blank.

From these four (4) words, choose the word that you think will make

sense and circle the letter in front of the word. Repeat this for all the

blanks and for all the passages until you are finished.

Part 1

259

a. suggest b. send c. see d. since

a. lab coat b. X-ray c. drill d. binuclear

a. clothes b. coffee c. muffins d. mouth

a. color b. fibers c. sugar d. fat

a. deposits b. dissolves c. drops d. deletes

a. grow b. eat c. be filled d. be measured

Passage 1:

When you go for a check-up, your dentist checks your fillings (if you have any), he/she may

________________you replace any loose or broken ones. Your dentist also looks for signs

of decay and may want to use an/a to take a closer look at the problem.

Cavities are caused when in the food we eat and bacteria in our mix

together to produce a mild acid that the outer layer of the tooth causing a

hole.

When you have a cavity in your tooth, it needs to .There are different

260

a. material b. decision c. occupation d. destination

a. is the dentist’s b. depends on the material c. depends on your pain d. is yours

a. because b. However c. whether d. then

a. turn b. forward c. around d. back

a. white b. colored c. yellow d. silver

a. seven b. five c. one d. ten

a. therefore b. such as c. moreover d. walk in

kinds of fillings to do the job, but the final on which type is placed in your

mouth __ .

There are two main types of fillings, metal and tooth-colored fillings. Dental amalgam fillings are

examples of metal fillings and __ they are silver in color they are

used to fill teeth. The other types of dental fillings are tooth-colored fillings;

composite fillings and are also called ________ _fillings.

Both metal and tooth-coloured fillings can usually be done in (1) visit.

261

a. ask your dentist about b. ignore c. tell your dentist to use d. not use

a. very small b. not seen c. large d. sealed

a. only a small part b. the damaged part c. the majority d. the infected part

a. protect b. prepare c. predict d. provide

a. damage b. break c. extract d. replace

There are other kinds of dental fillings which you can .

If the cavity is and your tooth is damaged but not lost, a crown may have

to be used to cover of your tooth and it will ___________ your

tooth from further damage.

However, if a tooth is badly damaged or lost, crowns cannot be used. Bridges and dentures are

two ways to __________ badly damaged teeth or lost teeth.

262

a. excessive drinking b. diabetes c. mental illness d. muscular dystrophy

a. science b. symptoms c. stimulation d. syphilis

a. periodontal disease b. preventive disease c. plantation disease d. retention disease

a. most b. more c. far d. big

a. Is b. The c. It d. At

a. on b. an c. any d. many

a. away b. any c. some d. always

Passage 2:

Research shows that there maybe a link between oral diseases and other health problems such

as heart disease and stroke as well as pre-term and low-birth

weight babies.

Gum disease is one of the ______ _ common dental problems. __ is also called

__________ ___ _ and it often develops slowly and without causing _________ pain.

You may not notice any until the disease is serious and you are in danger of

losing teeth. Fortunately, gum disease can be nearly _____________ prevented.

263

a. reversed b. revised c. released d. resounded

a. assesses b. affects c. efforts d. offers

a. sped up b. treated c. left alone d. no problem

a. saliva b. toothpaste c. plaque d. rinse

a. licking b. tooth brushing c. scraping with a finger d. swishing

a. stone b. calculus c. more tooth d. tongue deposits

a. a polishing b. instructions c. a scaling d. rinsing

a. during b. left c. right d. between

If it starts it can be ____ and even can be turned around or in its

early stages.

Gum disease the attachment that is located ______ _ the teeth and gums.

It begins with , which is clear and sticky and contains bacteria. If it is not

removed every day by with tooth brush and paste and floss, it

hardens into ______ , which can’t be removed by brushing and flossing.

Calculus can only be removed by by a dentist or dental hygienist.

264

a. gingivitis b. diabetes c. asthma d. angina

a. swelling b. redness c. pain d. etching

a. ice b. nerves c. attachment d. glass

a. become less of a problem b. abscess and fall out c. move to better position d. shorten

a. asthma b. diabetes c. anemia d. bleeding

The early stages of gum disease are called . It is characterized by mild

(color) and a bit of __ _ ______ when you brush. Over time, the infection

breaks down the between the gum and teeth. This is called attachment loss

and if it is not treated, the teeth become loose and may _________ .

265

Instructions:

In this part, you will be shown some drug labels and instructions after a

dental procedure. I will ask you some questions about them and you will

be asked to answer these questions orally.

Part 2

266

Q1: If you take the first tablet at Friday 10 a.m., when should you take the

next one?

(1) (0)

Q2: When should you take the last one? (1) (0)

Q3: If your symptoms are gone by the 4th day of taking the medication,

should you stop taking the medication?

(1) (0)

Q4: When should you stop the medication? (1) (0)

Q5: How many times you can refill this medication? (1) (0)

Total

Dania Sabbahi Refill: 00 1 Sept. 2011

Amoxicillin Capsules

500 MG 21/0

Take one tablet by mouth three (3) times a day for 7 days

267

Q1: How many capsules should you take per day? (1) (0)

Total


Penicillin V Capsules

500 MG 28/0

Take one tablet by mouth every 6 hours for 7 days.

268

Q1: What do you understand from this prescription? Can you swallow it? (1) (0)

Q2: If you use it at 5 p.m., when can you eat or drink? (1) (0)

Total


Chlorhexidine Mouthwash 0.12 %

Swish and spit 15cc for 30 seconds 3 times a day then nothing

per mouth for 30 minutes

269

Q1: If you are not feeling any pain, should you take the medication? (1) (0)

Q2: If you are feeling a pain, how many capsules can you take per day? (1) (0)

Q3: Can you take this medicine on June 2012? (1) (0)

Total


Ibuprofen

400 MG 20/0

Take one tablet by mouth every 4 hours when needed.

Expiration date: May 2012

270

Q1: How many times you have to take this medication? (1) (0)

Q2: If your dental appointment is scheduled at 10 a.m., when should you

take the medication?

(1) (0)

Total


Amoxicillin Capsules

500 MG 4/0

Take 4 tablets by mouth one hour before the dental appointment.

271

Q1: When is your next appointment? (1) (0)

Q2: Does this means that you leave home quarter to 10? “9:45 a.m.” (1) (0)

Q3: Where should you go? (1) (0)

Total

Appointment card

Clinic: Dental

Location: 1st floor

Date: February 27

Day: Tuesday

Time: 9:45 a.m.

272

Q1: If your tooth was extracted on Monday, when do you expect the

swelling to reach its maximum?

(1) (0)

Q2: If you start placing the ice bag at 10:00 a.m., when should you remove

it?

(1) (0)

Q3: When will you place the bag of ice for the second time? (1) (0)

Total

273

Appendix IX

276

Appendix X

277

Rapid Estimate of Adult Literacy in Dentistry (REALD-30)

Column 1 Column 2 Column 3 Column 4

Sugar Pulp Restoration Abscess

Smoking Denture Fluoride Incipient

Floss Enamel Plaque Halitosis

Brush Sealant Extraction Malocclusion

Braces Genetics Periodontal Gingiva

Caries Fistula Dentition

Cellulitis Bruxism

Hyperemia

Analgesia

Hypoplasia

Apicoectomy

Temporomandibular

The total score had a possible range of 0 (lowest literacy) to 30 (highest literacy).

278

Appendix XI

279

Critical and communicative oral health literacy questions

Have you had the following experiences in seeking the information related to your oral

health? Please circle one number against each statement.

Communicative Oral Health Literacy

Nev

er

Rar

ely

Som

etim

es

Oft

en

You have…

1. collected oral health related information from various sources. 1 2 3 4

2. extracted the oral health information you want. 1 2 3 4

3. understood the obtained oral health information. 1 2 3 4

4. communicated your thoughts about your oral health to someone. 1 2 3 4

5. applied the obtained information to your daily life. 1 2 3 4

Critical Oral Health Literacy N

ever

Rar

ely

Som

etim

es

Oft

en

You have…

1. considered whether the information was applicable to your situation.

1 2 3 4

2. considered the credibility of the information. 1 2 3 4

3. checked whether the information was valid and reliable. 1 2 3 4

4. collected information to make oral health-related decisions. 1 2 3 4

280

Appendix XII

281

Barrier Questionnaire

Q1 Have you received any dental information about the cause of your dental problems and how to prevent them during your initial visits to the Faculty of Dentistry Clinic’s?

c) Yes d) No (Please skip questions 2, 3 and 4 and go to question 5) Q2 How did you receive this information? (Please select all applicable) a) Verbally b) In writing (e.g. pamphlet) c) Electronically (referral to a website or via e-mail) Q3 Did you understand the information that was given to you? c) Yes (Please skip question 4 and go to question 5) d) No Q4 What was/were the reason/s for not understanding the given information? (Please

select all applicable) d) The information was complicated. e) The dentist did not spend enough time clarifying them. f) The dentist used terms that I did not understand. g) The clinical area was noisy and distractive. h) I was embarrassed to ask for clarification. Q5 Were you given time to ask questions about your dental status and treatment? a) Yes b) No (Please skip question 6 and go to question 7) Q6 Were all your questions answered to your satisfaction? a) Yes b) No Q7 Did you receive any instructions about improving your oral hygiene? a) Yes b) No (Please skip questions 8 and 9) Q8 Do you plan to follow these instructions? a) Yes b) No

282

Q9 If you have answered “NO” to question 8, Why? g) I cannot see the value of these instructions. h) I do not feel that applying theses instructions to my daily life will help

improving my oral hygiene and prevent my future problems. i) I do not have time to perform these practices. j) The cost of oral hygiene aids (e.g. tooth brush, floss and toothpaste) is high. k) My teeth hurt when I brush them. l) My gum bleeds when I brush my teeth.

association between oral health literacy and … · questionnaire (ipc) subscales 150 table 53...

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