periodontal disease: assessing the effectiveness …implications of cost-effectiveness analysis of...

Periodontal Disease: Assessing theEffectiveness and Costs of the Keyes

Technique

May 1981

NTIS order #PB81-221780

CASE S11JDY _5

THE IMPLICATIONS OF

COST-EFFECTIVENESS ANALYSIS OF

MEDICAL TECHNOLOGY

BACKGROUND PAPER #2: CASE STUDIES OF MEDICAL TECHNOLOGIES

CASE STUDY _5: PERIODONTAL DISEASE: ASSESSING THE eFFECTIVeNESS AND COSTS OF THE KEYES TECHNIQUE

C A S E S T U D Y # 5

THE IMPLICATIONS OF

COST-EFFECTIVENESSANALYSIS OF

MEDICAL TECHNOLOGY

MAY 1981

BACKGROUND PAPER #2: CASE STUDIES OFMEDICAL TECHNOLOGIES

C A S E S T U D Y #5: P E R I O D O N T A L D I S E A S E : A S S E S S I N G T H E

E F F E C T I V E N E S S A N D C O S T S O F T H E K E Y E S T E C H N I Q U E

Richard M. Scheffler, Ph. D.Visiting Associate Professor of Health Economics

School of Public Health, University of California, Berkeley

Sheldon Rovin, D. D. S., M.S.Chairperson, Department of Dental Care Systems

School of Dental Medicine, University of Pennsylvania, Philadelphia, Pa.

With commentary edited by: Allan J. Formicola, D. D. S., Dean, School of Dental and Oral Surgery,Columbia University, New York

OTA Background Papers are documents that contain information believed to beuseful to various parties. The information undergirds formal OTA assessments or isan outcome of internal exploratory planning and evaluation. The material is usuallynot of immediate policy interest such as is contained in an OTA Report or TechnicalMemorandum, nor does it present options for Congress to consider.

Library of Congress Catalog Card Number 80-600161

For sale by the Superintendent of Documents,U.S. Government Printing Office, Washington, D.C. 20402

Foreword

This case study is one of 17 studies comprising Background Paper #2 for OTA’sassessment, The Implication of Cost-Effectiveness Analysis of Medical Technology.That assessment analyzes the feasibility, implications, and value of using cost-effec-tiveness and cost-benefit analysis (CEA/CBA) in health care decisionmaking. The ma-jor, policy-oriented report of the assessment was published in August 1980. In additionto Background Paper #2, there are four other background papers being published inconjunction with the assessment: 1 ) a document which addresses methodologicalissues and reviews the CEA/CBA literature, published in September 1980; 2) a casestudy of the efficacy and cost-effectiveness of psychotherapy, published in October1980; 3) a case study of four common diagnostic X-ray procedures, to be published insummer 1981; and 4) a review of international experience in managing medical tech-nology, published in October 1980. Another related report was published inSeptember of 1979: A Review of Selected Federal Vaccine and Immunization Policies.

The case studies in Background Paper #2: Case Studies of Medical Technologiesare being published individually. They were commissioned by OTA both to provideinformation on the specific technologies and to gain lessons that could be applied tothe broader policy aspects of the use of CEA/CBA. Several of the studies were specifi-cally requested by the Senate Committee on Finance.

Because of particular circumstances regarding this case study on interventions forperiodontal disease, a commentary by a group of dental scientists and clinicians ispresented immediately folIowing the case study. The case study authors’ response ispresented after the commentary.

Drafts of each case study were reviewed by OTA staff; by members of the ad-visory panel to the overall assessment, chaired by Dr. John Hogness; by members ofthe Health Program Advisory Committee, chaired by Dr. Frederick Robbins; and bynumerous other experts in clinical medicine, health policy, Government, and econom-ics. We are grateful for their assistance. However, responsibility for the case studies re-mains with the authors.

Director

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Advisory Panel on The Implications ofCost= Effectiveness Analysis of Medical Technology

John R, Hogness, Panel ChairmanPresident, Association of Academic Health Centers

Stuart H. AltmanDeanFlorence Heller SchoolBrandeis University

James L. BenningtonChairmanDepartment of Anatomic Pathology and

Clinical LaboratoriesChildren Hospital of San Francisco

John D. ChaseAssociate Dean for Clinical AffairsUniversity of Washington School of Medicine

Joseph FletcherVisiting ScholarMedical EthicsSchool of MedicineUniversity of Virginia

Clark C. HavighurstProfessor of LawSchool of LawDuke University

Sheldon LeonardManagerRegulatory AffairsGeneral Electric Co.

Barbara J. McNeilDepartment of RadiologyPeter Bent Brigham Hospital

Robert H. MoserExecutive Vice PresidentAmerican College of Physicians

Frederick MostellerChairmanDepartment of BiostatisticsHarvard University

Robert M. SigmondAdvisor on Hospital AffairsBlue Cross and Blue Shield Associations

Jane Sisk WillemsVA ScholarVeterans Administration

OTA Staff for Background Paper #2

Joyce C. Lashof, Assistant Director, OTAHealth and Life Sciences Division

H. David Banta, Health Program Manager

Clyde J. Behney, Project Director

Kerry Britten Kemp, * EditorVirginia Cwalina, Research Assistant

Shirley Ann Gayheart, SecretaryNancy L. Kenney, Secretary

Martha Finney, * Assistant Editor

Other Contributing Staff

Bryan R. Luce Lawrence Miike Michael A. Riddiough

OTA Publishing

Leonard Saxe Chester Strobel*

Staff

John C. Holmes, Publishing Officer

John Bergling* Kathie S. Boss Debra M. DatcherPatricia A. Dyson* Mary Harvey* Joe Henson

● OTA contract personnel.

Preface

This case study is one of 17 that compriseBackground Paper #2 to the OTA project on theImplications of Cost-Effectiveness Analysis ofMedical Technology. * The overall project wasrequested by the Senate Committee on Laborand Human Resources. In all, 19 case studies oftechnological applications were commissionedas part of that project. Three of the 19 were spe-cifically requested by the Senate Committee onFinance: psychotherapy, which was issued sepa-rately as Background Paper #3; diagnostic X-ray, which will be issued as Background Paper#5; and respiratory therapies, which will be in-cluded as part of this series. The other 16 casestudies were selected by OTA staff.

In order to select those 16 case studies, OTA,in consultation with the advisory panel to theoverall project, developed a set of selectioncriteria. Those criteria were designed to ensurethat

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as a group the case studies would provide:

examples of types of technologies by func-tion (preventive, diagnostic, therapeutic,and rehabilitative);examples of types of technologies by physi-cal nature (drugs, devices, and procedures);examples of technologies in different stagesof development and diffusion (new, emerg-ing, and established);examples from different areas of medicine(such as general medical practice, pedi-atrics, radiology, and surgery);examples addressing medical problems thatare important because of their high fre-quency or significant impacts (such ascost);examples of technologies with associatedhigh costs either because of high volume(for low-cost technologies) or high individ-ual costs;examples that could provide informativematerial relating to the broader policy andmethodological issues of cost-effectivenessor cost-benefit analysis (CEA/CBA); and

● Office of Technology Assessment, U.S. Congress, The lmplica-tions of Cost-Effectiveness Analysis of Medical Technology, GPOstock No. 052-003 -00765-7 (Washington, D. C.: U.S. GovernmentPrinting Office, August 1980).

● examples with sufficient evaluable litera-ture.

On the basis of these criteria and recommen-dations by panel members and other experts,OTA staff selected the other case studies. These16 plus the respiratory therapy case study re-quested by the Finance Committee make up the17 studies in this background paper.

All case studies were commissioned by OTAand performed under contract by experts in aca-demia. They are authored studies. OTA sub-jected each case study to an extensive reviewprocess. Initial drafts of cases were reviewed byOTA staff and by members of the advisorypanel to the project. Comments were providedto authors, along with OTA’s suggestions forrevisions. Subsequent drafts were sent by OTAto numerous experts for review and comment.Each case was seen by at least 20, and some by40 or more, outside reviewers. These reviewerswere from relevant Government agencies, pro-fessional societies, consumer and public interestgroups, medical practice, and academic med-icine. Academicians such as economists and de-cision analysts also reviewed the cases. In all,over 400 separate individuals or organizationsreviewed one or more case studies. Although allthese reviewers cannot be acknowledged indi-vidually, OTA is very grateful for their com-ments and advice. In addition, the authors ofthe case studies themselves often sent drafts toreviewers and incorporated their comments.

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studies on gastrointestinal endoscopy andon the Keyes technique for periodontal dis-ease, commentaries from experts in the ap-propriate health care specialty have been●

included, followed by responses from theauthors.

The case studies were selected and designed tofulfill two functions. The first, and primary,purpose was to provide OTA with specific in-formation that could be used in formulatinggeneral conclusions regarding the feasibility andimplications of applying CEA/CBA in healthcare. By examining the 19 cases as a group andlooking for common problems or strengths inthe techniques of CEA/CBA, OTA was able tobetter analyze the potential contribution thatthese techniques might make to the managementof medical technologies and health care costsand quality. The second function of the caseswas to provide useful information on the spe-cific technologies covered. However, this wasnot the major intent of the cases, and theyshould not be regarded as complete and defini-tive studies of the individual technologies. Inmany instances, the case studies do represent ex-cellent reviews of the literature pertaining to thespecific technologies and as much can stand ontheir own as a useful contribution to the field. Ingeneral, through, the design and the fundinglevels of these case studies was such that theyshould be read primarily in the context of theoverall OTA project on CEA/CBA in healthcare.

Some of the case studies are formal CEAS orCBAS; most are not. Some are primarily con-cerned with analysis of costs; others are moreconcerned with analysis of efficacy or effec-tiveness. Some, such as the study on end-stagerenal disease, examine the role that formalanalysis of costs and benefits can play in policyformulation. Others, such as the one on breastcancer surgery, illustrate how influences otherthan costs can determine the patterns of use of atechnology. In other words, each looks at eval-uation of the costs and the benefits of medicaltechnologies from a slightly different perspec-

tive. The reader is encouraged to read this studyin the context of the overall assessment’s objec-tives in order to gain a feeling for the potentialrole that CEA/CBA can or cannot play in healthcare and to better understand the difficulties andcomplexities involved in applying CEA/CBA tospecific medical technologies.

The 17 case studies comprising BackgroundPaper #2 (short titles) and their authors are:

Artificial Heart:, Deborah P. Lubeck and John P.Bunker

Automated Multichannel Chemistry Analyzers:Milton C. Weinstein and Laurie A. Pearlman

Bone Marrow Transplants: Stuart O. Schweitz-er and C. C. Scalzi

Breast Cancer Surgery: Karen Schachter andDuncan Neuhauser

Cardiac Radionuclide Imaging: William B.Stason and Eric Fortess

Cervical Cancer Screening: Bryan R. LuceCimetidine and Peptic Ulcer Disease: Harvey V.

Fineberg and Laurie A, PearlmanColon Cancer Screening: David M. EddyCT Scanning: Judith L. WagnerElective Hysterectomy: Carol Korenbrot, Ann

B. Flood, Michael Higgins, Noralou Roos,and John P. Bunker

End-Stage Renal Disease: Richard A. RettigGastrointestinal Endoscopy: Jonathan A. Show-

stack and Steven A. SchroederNeonatal Intensive Care: Peter Budetti, Peggy

McManus, Nancy Barrand, and Lu AnnHeinen

Nurse Practitioners: Lauren LeRoy and SharonSolkowitz

Orthopedic Joint Prosthetic Implants: Judith D.Bentkover and Philip G. Drew

Periodontal Disease Interventions: Richard M.Scheffler and Sheldon Rovin

Selected Respiratory Therapies: Richard M.Scheffler and Morgan Delaney

These studies will be available for sale by theSuperintendent of Documents, U.S. Govern-ment Printing Office, Washington, D.C. 20402.Call OTA’s Publishing Office (224-8996) foravailability and ordering information.

viii

Case Study #5

Periodontal Disease: Assessingthe Effectiveness and Costs

of the Keyes Technique

Richard M. Scheffler, Ph. D.Visiting Associate Professor of Health Economics*

School of Public HealthUniversity of California, Berkeley


School of Dental MedicineUniversity of Pennsylvania

Philadelphia, Pa.

AUTHORS’ ACKNOWLEDGMENTS

The authors would like to take this opportunity to thank the following individ-uals and organizations for their helpful suggestions on the earlier drafts of our report:Dr. John F. Goggins, National Institute for Dental Research, National Institutes ofHealth; Drs. Sigmund Socransky, J. Max Goodson, and Anne Tanner, Forsyth DentalCenter; Dr. Phillip Canon, Beth Israel Hospital; the staff of the National Center forHealth Services Research, Department of Health and Human Resources; and the staffof Division of Dentistry, Department of Health and Human Resources.

*On leave from Department of Economics, George Washington University, Washington, D.C.

Contents

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * . . ,

Periodontal Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Traditional Technologies Used To TreatPeriodontal Disease. . . . . .Nonsurgical Technologies. . . . . . . . . . . . . . . . . . . . . . . . . . . . .Surgical Technologies . . . . . . . . . . . . . . . . . . . . . . . ........0

The Keyes Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

New Evidence on the Effectiveness and Cost of the Keyes TechniqueData Collection. . . . . . . . . . . . . . . . . . . . . . ● ** . .** .*** .***The Effectiveness of the Keyes Technique . . . . . . . . . . . . . . . . .The Delivery and Cost of the Keyes Technique. . . . . . . . . . . . .

Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ● * * * . * * . . . . * * .

Appendix A: Glossary of Dental Terms . . . . . . . . . . . . . . . . . . . . . .Appendix B: Questionnaire Used To Collect Data . . . . . . . . . . . . . .

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Commentary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ● . * * * * ,

Authors’ Response to Commentary . . . . . . . . . . . . . . . . . . . . . . . . .

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Periodontal Disease

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Case Study #5:

Periodontal Disease: Assessingthe Effectiveness and Costs


Richard M. Scheffler, Ph. D.Visiting Associate Professor of Health Economics

School of Public HealthUniversity of California, Berkeley


School of Dental MedicineUniversity of Pennsylvania

Philadelphia, Pa.

INTRODUCTION

Of the $13.3 billion spent on dental care in1978, approximately $350 million was spent ontreating periodontal disease (10,12). About $250million of this was received by periodontists(dentists who specialize in treating periodontaldisease); the remaining $100 million was re-ceived by general dental practitioners who de-livered periodontal services. ’

A significant portion of expenditures for peri-odontal disease is for periodontal surgery. Suchsurgery can be quite expensive. Two types ofperiodontal surgery, mucogingival (gum) sur-gery and osseous (bone) surgery, for example,per quadrant of the mouth often cost the patient

‘The $100 million estimate for general practitioners was derivedby multiplying national expenditures on dental care ($13.3 billion)(12) by 0.78 percent, which is the percentage of total expenditurescollected by general dentists for periodontal services (10). The esti-mate of $250 million received by periodontists was derived by add-ing the average income of periodontists, $56,741, to the averageexpenses for all dental practices, $56,303 (3) for 1976 and adjustingfor inflationary increases of 6 percent per year to express it in 1978dollars. This sum ($126,144) was then multiplied by the approx-imately 2,000 periodontists practicing in 1978.

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peroxide and baking soda and in some casesdrugs), and assessment of bacterial control byregular microscopic examination of materialfrom the periodontal tissues. It involves the useof water irrigation of the gums and other easilylearned hygiene procedures. Some claim that, ifproperly used, the Keyes technique could reducedramatically the quantity of peridontal sur-gery performed.

In the next three parts of this case study, wepresent layman’s definitions of periodontal dis-ease; a description of the technologies currentlybeing used on a widespread basis to prevent andtreat periodontal disease and an assessment ofwhat is known about their effectiveness, basedon a review of the literature: and a descriptionof the Keyes rationale and how it may be usedfor diagnosing, controlling, and preventing

periodontal disease.

Next, we present some preliminary results ofour recent study on 18 dental practices in theWashington, D. C., Standard Metropolitan Sta-

PERIODONTAL DISEASE

Tooth loss, in contrast to popular opinionand mythology, is not a natural concomitant ofage—it is caused by disease processes. The dis-ease processes of the periodontal, or supporting,structures of the teeth, known collectively as“periodontal disease” or “periodontal infec-t i on,” are responsible for 70 percent of all toothextraction and are the principal cause of toothloss (6,13,15,33).

Data show that some form of periodontal dis-ease affects anywhere from 75 percent to vir-tually all of the adult population in the UnitedStates, and a destructive form involving tissueloss affects approximately one-third of the adultpopulation (6, 15,16,22,29). Periodontal diseasedoes afflict children, but it is more common andmore severe among adults. Although the diseaseincreases in prevalence and severity with age, itis not the aging process that causes it; rather, itis the length of time that the teeth and sup-portive tissues are exposed to the causative fac-tors (21 ).

tistical Area (SMSA) that use the Keyes tech-nique. With data on 190 patients and over 800dental visits, we provide a short-term assess-ment of the effectiveness of the Keyes techniqueand estimate the cost of delivering the Keyestechnique to the patients in our study. The re-sults of our study provide new and useful dataon the Keyes technique, but larger scale andlong-term studies are needed before more defini-tive conclusions can

The final part ofsum mar y of someAlso discussed are abe taken in order to

be drawn.

this study contains a briefof our major conclusions.few of the steps that need toallow a complete cost-effec-

tiveness analysis (CEA) of the Keyes technique.We did not perform a CEA of the current tech-nologies used for treating periodontal disease,and no such analysis is available in the pub-lished literature. Hence, we are unable to com-pare the cost effectiveness of the Keyes tech-nique to the cost effectiveness of the currenttreatment of periodontal disease.

One of the difficulties in dealing with peri-odontal disease is its insidiousness. The onset ofdisease is gradual. Afflicted individuals are gen-erally symptomless for long periods of time.Often patients have extensive disease, involvingthe loss of supporting structures and formationof deep pockets around the teeth, without beinguncomfortable or even aware of the problem.All too often patients will have undiagnosedperiodontal disease for years even though theyhave been regularly seen by a dentist.

The reasons for undiagnosed periodontal dis-ease are several. Many dentists concentrate onlyon restorative problems of the teeth and thus ig-nore or fail to recognize periodontal disease un-til it has progressed to an advanced stage. Thediagnosis of early or incipient periodontaldisease requires not only visual inspection, butprobing, staining for plaque, and radiographic(X-ray) diagnosis; typical symptoms such as badbreath, spontaneous bleeding, and pain tend tooccur only after the disease has progressed to

Case Study #5: Periodontal Disease: Assessing the Effectivenedd and Costs of the Keyes Technique ● 5

the moderate or advanced stage. Furthermore,some dentists may not have been adequatelytrained in diagnosing and treating periodontaldisease.

As is the case with many other chronic dis-eases, early diagnosis of periodontal disease af-fords a better chance for successful treatment. Ifdisease is detected early, therapy requires lesstime and effort by the dentist, less discomfort tothe patient during therapy, less difficult oralhygiene measures by the patient, and consider-ably less cost. Moreover, the destructive formof periodontal disease first goes through a rela-tively innocuous inflammatory stage, and, if di-agnosed and treated at that time, the disease isin most instances easily reversible. The univer-sality of periodontal disease is the most vexingpart of the problem, because in over 90 percentof instances, such disease is potentially prevent-able by relatively inexpensive means known andavailable today (13,28,29).

Periodontal disease is a disease complex, agroup of diseases placed under a single headingfor purposes of convention. The term “peri-odontal disease” is generally used to refer towhat are by far the two most prevalent peri-odontal diseases: gingivitis and periodontitis.Gingivitis is inflammation of the gingiva (gum)only and is generally considered a reversibleprocess (8). Periodontitis is inflammation ofboth the gum and the other supporting struc-tures of the teeth (i. e., the outer bone of thetooth socket, the outer layer (cementum) of theroot of the tooth, and the soft tissues which at-tach these structures to one another). Periodon-titis also connotes destruction or loss of the sup-porting structures of the teeth. Once destructiontakes place, complete regeneration of the af-fected tissues does not occur (8). The l0SS ordestruction of the supporting structures resultsin the formation of pathologic spaces or pocketsaround the teeth. 5 If this process continues, theteeth lose their supporting structure, becomeloose, and eventually have to be removed. Un-fortunately, no accepted diagnostic method to

5The normal space between the gum and the tooth is called aSUlCUS. When this space deepens or extends past its normal bound-ary as a result of the inflammatory process, it is called a pocket.

determine at a given point in time whether thedestructive process is active or quiescent is cur-rently available (14), a circumstance with sig-nificant therapeutic implications.

Experientially, most dentists feel that the pro-gression of gingivitis to periodontitis is part of acontinuum (25), i.e., if gingivitis persists longenough, it will inevitably progress into peri-odontitis. However, there is no documented sci-entific evidence for this view. It is known thatperiodontitis does not develop in the absence ofgingivitis (25); and it does appear that, in mostinstances, untreated gingivitis will progress intoperiodontitis (25). At the same time, there isgreat variability in the time it takes for progres-sion to occur (gingivitis per se may exist formany years); and in some instances, progressiondoes not occur at all (8,25). The distinction be-tween gingivitis and periodontitis is empha-sized, because gingivitis, by far the most com-mon form of periodontal disease, is relativelyinnocuous. Most important, it is potentiallyreversible in a majority of instances. Uncom-plicated by any other factor, gingivitis is usuallyrelatively easy to treat with methods that pro-duce little or no discomfort to patients, and thecost of treating gingivitis is a small portion ofwhat it costs to treat destructive periodontitis.

Bacteria] infection is the essential factor in theinitiation and propagation of periodontal dis-ease (30,32). The exact mechanisms by whichthe germs produce their deleterious effects re-main undiscovered, but there is little doubt thatbacteria are the principal cause of periodontaldisease. The sine qua non in the etiology of peri-odontal disease is the presence of a microbialpopulation in the form of dental (or bacterial)plaque. Dental plaque is a gummy bacterial sub-stance that adheres to the teeth; it cannot beseen by the naked eye, but is easily demon-strated by various stains. In the absence ofbacterial plaque, periodontal disease does notoccur; removal of such plaque halts the progres-sion of, produces remission of, or reverses ex-isting disease. Further evidence of the role ofbacteria in causing periodontal disease is thefact that antimicrobial agents are often effectivein controlling such disease (25,32).

6 ● Background Paper #2: Case Studies of Medical Technologies

Bacterial populations in the mouth differunder conditions of health and of disease, afinding which has also has therapeutic implica-tions (13). Furthermore, the same evidencepoints to differences in the microbial composi-tion of gingivitis and periodontitis. The im-portance of the role of bacteria in causing perio-dontal disease must be emphasized, because thefundamental aim of periodontal treatment is tocontrol bacterial plaque or to facilitate its con-trol by the patient, and the principal goal ofprevention is to inhibit its formation.

Faulty or improperly placed margins of dentalrestorations (fillings) are recognized as a factorcontributing to periodontal disease (21,29). Inthe face of these margins, plaque accumulatesreadily, and the existing inflammatory processis enhanced. What is not clear is whether faulty

margins actually initiate or just worsen the dis-ease process. In either case, improper marginshave to be dealt with as a part of treatment.

There are other factors allegedly associated,causally, with periodontal disease. A list wouldinclude, in no relative order of importance,malocclusion (malpositioning of the jaws withrespect to one another), faulty tooth position,genetic predisposition, systemic disease such asdiabetes mellitus, and malnutrition. No furtherdiscussion about these factors is warranted,since they are not thought to be essential incausing periodontal disease, and at most areconsidered adjunctive to periodontal disease(i.e., they might exacerbate preexisting peri-odontal disease) (21,25,34). Also, the considera-tion of these factors in a CEA of periodontaltherapy would be negligible.

TRADITIONAL TECHNOLOGIES USED TO TREATPERIODONTAL DISEASE

The traditional technologies used to treatperiodontal disease can be placed into twobroad general categories—nonsurgical andsurgical.

Nonsurgical Technologies

Plaque Control

There is aship betweenand gingivalDaily plaqueconducive to.* *

well-documented, direct relation-the frequency of plaque removaland periodontal health (5,29,31).removal is considered optimallygingival health. Obviously, indi-

viduals cannot have dental care professionalsremove plaque every clay. Patients must learn toremove plaque by themselves, a task not ter-ribly onerous, but requiring some knowledgeand mastery of technique.

The plaque control programs of periodontaltherapy are aimed at instructing patients in theoral hygiene techniques that will remove plaqueand prevent it from accumulating in harmfulamounts. Basically, these oral hygiene tech-niques are the application of stain to detectplaque and the brushing and flossing of teeth to

remove it. Professionally supervised practice ofthese techniques is usually a basic part of peri-odontal therapy. The outcome of periodontaltherapy depends on how well the patient con-trols plaque formation. In the absence of plaquecontrol, any therapy is of little or no value(4,23,26,29).

On the basis of the prevalence of periodontaldisease (6,16,22), it appears that, unfortunately,most people do not effectively control plaqueformation, including many who have had exten-sive instruction and have been treated for de-structive periodontal disease. The issue is notsimple. Plaque control is more than a questionof instruction about the proper methods. It re-quires individuals to change or modify their be-havior so they not only know the correct meth-ods, but are motivated to use them routinely.

Scaling and Root Planing

Scaling and root planing are professionallyapplied mechanical techniques. Scaling is usedto remove calculus (hard deposits) from theteeth, root planing to smooth the root surfaces,

Case Study #s: Periodontal Disease: Assessing the Effectiveness and Costs of the Keyes Technique ● 7

ostensibly to make the roots less susceptible tomicrobial activity. The largest proportion of thetime and effort expended in treating patientswith periodontal disease is devoted to scalingand root planing (11). In some instances, sur-gical techniques are used to make the roots moreaccessible to this type of instrumentation.

Although it is generally assumed that the gin-giva are irritated by the mere physical presenceof calculus, this assumption awaits substantia-tion by scientific data (9). The microbial plaquecovering the calculus is the noxious agent. Re-moval of gross or obvious calculus appears tobe indicated; however, what is not clear iswhether it is worthwhile to spend the time andeffort required to remove small amounts of cal-culus that are difficult to detect, particularlysince plaque re-forms in 24 to 36 hours (19,29).

There is also disagreement about the benefitsof root planing. The little evidence availablesuggests that the primary rationale for rootplaning is to remove calculus; root smoothnessmay be inconsequential in retarding plaque for-mation (11,29). At any rate, the most importantdeterminant of periodontal health is the degreeto which patients exercise plaque control(23,27,29).

Another issue relates to the frequency of pro-phylaxis (professional scaling) required to main-tain periodontal health. A landmark study indi-cates that the optimal frequency is at 2-week in-tervals (5). However, other data suggest thatquarterly intervals are also beneficial, althoughnot as effective as 2-week intervals (29). Again,the benefits of scaling are believed to be less im-portant than the patient’s personal oral hygieneand plaque control. Unfortunately, more peoplerely on the dentist or hygienist for prophylaxesthan practice good plaque control themselves.Thus, the issue of frequency must be examined,particularly from a standpoint of cost effective-ness. On the basis of available evidence, pro-phylaxis at 2-week intervals would be cost pro-hibitive for most individuals. Moreover, givencurrent methods of dental practice, there is in-adequate manpower to routinely clean people’steeth at 2-week intervals.

Correcting Margins of Restorations

Since improper margins of dental restorationscontribute either to the initiation or severity ofperiodontal disease, the correction of such mar-gins is an integral part of therapy. The most im-portant reason for correcting improper marginsis to facilitate plaque control, because in the faceof an overhanging restoration, for example,plaque removal is exceedingly difficult. Gener-ally, correction in the form of reducing bulk orsmoothing is done at the time of scaling androot planing; but it is a requirement of peri-odontal therapy regardless of when it is done.

Chemotherapy

Substantiation of the fact that micro-orga-nisms are a primary causative factor in peri-odontal disease has sparked much interest inchemotherapeutic control measures (1,20,29,30). Some of the initial attempts to control peri-odontal disease with certain antimicrobialagents have been successful, but these attemptsmust be considered only trials. Essentially, in-sufficient evidence is available to warrant theroutine use of these agents (29). Furthermore, alimitation of the studies thus far conducted isthat they have been short-term. Periodontaldisease is of long duration and requires whatamounts to a lifetime of effort in controllingplaque formation; an antimicrobial agent maysuppress bacteria or reduce plaque formation ina short-term clinical trial, but this does notmean that it will do so effectively and safely,without side-effects, for a long period of time.Nonetheless, further chemotherapeutic experi-mentation is warranted. However, at this time,chemotherapy is not considered a primary tech-nology in the control of plaque or periodontaldisease.

‘Chemotherapy, the use of chemical agents—in this case antibi-otics—to treat disease, is not an accepted, routine part of peri-odontal therapy. It is included here because the role of micro-orga-nisms in causing periodontal disease has been shown only recently,and the principal method of treating microbial diseases generally iswith these agents. As specific bacteria are identified as causativeagents, much more emphasis is likely to be placed on the use ofchemotherapy. The discussion of chemotherapy is also includedbecause of cost implications.

8 ● Background paper #.?: Case Studies of Medical Technologies

Surgical TechnologiesPeriodontal surgery, in one form or another,

is a common procedure used to eliminate thepockets that occur in destructive periodontaldisease (24). Different surgical techniques areused for different purposes. Eliminating pock-ets, making root surfaces more accessible to re-moving plaque, inducing reattachment of tis-sues, and restoring destroyed tissues are themain clinical objectives of employing these tech-niques (7). In practice, two or more techniquesoften are used together to achieve a specificresult.

Regardless of the objective of the specific sur-gical method, the fundamental rationale of peri-odontal surgery is to prolong the functional lifeof the teeth. The ultimate success or failure ofthe particular surgical method, therefore,should be judged by the extent to which themethod conserves tooth life. Unfortunately,there are few baseline data on which to makeobjective evaluations. With only a few excep-tions (7,23,24), the studies of the differentsurgical methods are short term. Longitudinalstudies (longer than 5 to 10 years) required ofdiseases having the apparent chronicity of peri-odontal disease are needed. Until such scientific

THE KEYES TECHNIQUE

Dr. Paul Keyes and associates have developedand are testing a technology they believe sup-presses plaque microbes and arrests, or marked-ly abates, the progression of destructive peri-odontal disease (17,18). This technology in-volves the use of a meticulous diagnostic andtherapeutic regimen, the latter involving the ap-plication of certain salt solutions in all in-stances, and periodic courses of systemic anti-biotics when indicated. Therapeutic regimensare based on microscopic sampling of plaque inthe pocket areas as a means of monitoring bac-terial activity. An integral part of the Keyes pro-gram is to show the patient the actual bacteri-ologic activity in the periodontal tissues thougha microscope, the intent being to convince thepatient of the extent of the problem and to moti-

studies have been carried out, objective meas-urements of surgical effectiveness must remaintentative at best.

Those studies that have been done do notunequivocally point to one technique’s beingsuperior to another (7,23,24,27). Moreover, al-though the reasons for doing periodontal sur-gery can be supported experientially, scientificevidence does not show that any of these sur-gical techniques alone is effective in prolongingthe life of the teeth. Periodontal surgery makesno difference in the absence of reasonable oralhygiene by patients combined with professionalmaintenance (23,24,26,27). The surgery by itselfwill not restore health to diseased periodontaltissues.

In summary, we conclude that there is consid-erable controversy surrounding the efficacy ofthe various surgical techniques used in the treat-ment of periodontal disease. It is also fair tonote that the emphasis on surgical technologymay be misplaced (29) and the type of surgerythat is performed is considered far less impor-tant than whether or not the teeth can be main-tained in a state of good oral hygiene (4,23,24,26,27).

vate him or her to help in its remediation. Oralhygiene and plaque control instruction is givenin a slow, stepwise fashion over a 3- to 4-weekperiod. Patients are also advised to rinse theirmouths after eating, whenever possible, and touse a pulsed-water irrigation device, such as aWater Pik, once a day.

Earlier we stated that there is no diagnosticmethod available to determine whether or notdestructive periodontal disease is in an activestate. The Keyes method purports to distinguishactive from inactive disease by assessing thespecific microbial population and inflammatoryprocess in the pocket area. Dr. Keyes assertswhat others believe but are not willing to assertwithout more substantiating evidence—that the

Case Study #.5: Periodontal Disease: Assessing the Effectiveness and Costs of the Keyes Technique ● 9

specific bacteria identified via the microscopeare predictors of pathologic status and that thebacteria associated with disease differ fromthose found in healthy periodontal tissues. Withthe information obtained via microscopic exam-ination, treatment is initiated which is aimed atsuppressing the microbial population and facili-tating the patient in controlling plaque forma-tion.

Although the Keyes method is still in the earlystages of being tested, Keyes has reportedmarked improvement in patients he has treated(18). It should be emphasized that the effec-tiveness of the Keyes method, like that of othertreatments, depends on the patient’s assiduouslyfollowing the prescribed plaque control pro-gram (18). If it turns out that the Keyes methodis as effective as its developers believe, then thatwould mean, among other things, that the pa-tients using the Keyes method are doing a betterjob of controlling plaque than they would withother technologies. That in itself would be amost significant outcome.

Many individuals do not practice good oralhygiene. Even patients who have undergone ex-tensive periodontal surgery and have receivedintensive oral hygiene instruction as a part oftherapy often do not exercise adequate plaquecontro; the recurrence rate of periodontal dis-ease in such patients is high (24). If the Keyesmethod proves more effective than others, thatwill mean that something about this methodenables or makes it easier for patients to exerciseplaque control better than the other methodsused to date. It could be the Keyes method’sslow, stepwise fashion of patient instruction.Possibly, showing patients microbes taken fromtheir tissues under a microscope impresses thenature of the problem upon the patients in amore effective manner. This is only speculation,and, of course, it is far too soon to tell if theKeyes technique has lasting effect. Much moreevaluation—particularly long-term evaluation—is needed. (In the next part of this case study,we present the first systematic assessment of theeffectiveness of the Keyes technique in multiplepractice sites. )

Figure 1 shows some of the important similar-ities and differences between the Keyes and tra-

ditional technologies for treating periodontaldisease. The “traditional” technology is shownin the lower half of the figure and the steps arelabeled by capital letters. The “Keyes” technol-ogy is shown in the upper half of the figure, withthe steps labeled by lower case letters.

Regardless of which technique will be appliedto an individual patient, all patients—those whowill be managed traditionally as well as thosewho will not—initially go through about thesame diagnostic and treatment planning proce-dures. Once periodontal disease is diagnosed(Aa), patients can be treated either by “tradi-tional” methods or the “Keyes” method. At thisjuncture, all patients with periodontal diseasereceive oral hygiene instruction and extensivetooth cleaning (scaling and root planing), see (B)and (b) on the figure. A comparison of (B) and(b) shows that the patients being treated by theKeyes method also receive a microscopic exam-ination and are placed on a regimen that in-cludes salt-solution therapy.

In patients being treated by the “traditional”method, a determination is then made of thepresence or absence of pockets (C). If there areno pockets but disease is present (D), the patientreceives further tooth cleaning and hygiene in-struction (B). If pockets are present, some formof surgery is usually, but not always, performed(E). After surgery, if disease persists or recurs(D), the patient receives additional tooth clean-ing and hygiene instruction (B). If no pocketsare present and the patient is in reasonable oralhealth (F), a maintenance phase is begun (G).

In patients being treated by the “Keyes” meth-od, by contrast, oral hygiene instruction andbacteriologic monitoring continue (c), but thereis no surgery. If disease (d) persists, the patientis generally placed for 2 weeks on a regimen ofantibiotics, 7 and oral hygiene instruction, mi-croscopic examination, and tooth cleaning arecontinued (b). If the patient is in reasonable oralhealth (f), a maintenance phase is begun (g).

The Keyes technology differs from the tradi-tional method of treating periodontal disease inthree essential ways: 1 ) Microscopic diagnosis

‘Antibiotics may also be used in the traditional method, but arenot used as routinely.

I No periodontal

I I

monitoringI *

Health 1 (f)● *

Traditional

and monitoring of microbial activity is the basisfor therapeutic decisions; 2) salt solutions areused routinely and antibiotics are used often;and 3) periodontal surgery to eliminate pocketsis used infrequently, since complete pocket elim-ination is not a goal of the Keyes method. TheKeyes method is founded on Keyes’ belief thathalting the progression of the destructive proc-ess and allowing natural healing to occur doesnot depend on surgical elimination of the pock-et, but does depend on controlling bacterialactivity.

in figure 1 are general, and some of the par-ticular steps may differ, especially in the “tradi-tional” technology. These differences or changesdepend on several factors, such as extent of dis-ease, the patient’s overall health, the patient’sability or willingness to pay, and the personaltreatment philosophy of the practitioner. Also,it should be reemphasized that the ultimate suc-cess of therapy, regardless of method, dependsmore on how well the patient practices goodoral hygiene than on what the dentist does forthe patient.

It should be emphasized that the steps shown

OF THE KEYES TECHNIQUE

Data Collection

To perform our study of the effectiveness andcost of the Keyes technique, we collected data in1979 on 18 dental practices from the Washing-ton, D. C., SMSA that currently use this tech-nique. 8 Using written questionnaires, we col-lected data on each practice and on a selection ofthe patients in each practice who are currentlybeing treated with the Keyes technique. ’

Data on 8 of the practices were obtained via amail survey, and data on the other 10 were col-lected by dental students. ’” All 18 of the dentalpractices surveyed were owned and operated bysolo general practitioners. The average age ofthese practitioners was 47. The average lengthof time they had been in practice was almost 12years; they had used the Keyes technique for13.7 months on the average.

Using information from the patients’ records,we completed a written questionnaire on about10 patients in each practice who were beyondtheir initial visit for the Keyes technique. 11 Thequestionnaire used to collect data on individualpatients is reproduced in appendix B. Using thisquestionaire, we obtained data relating to thepatient’s oral health status before treatment andat the time the questionnaire was administered.Data were also obtained on the services deliv-ered to the patient during the first six visits andthe maintenance visit, on who delivered theseservices, and in what amount of time. Thecharges for each visit were also recorded. Usable

‘Currently, there are 26 dental practices using the Keyes tech-nique in the Washington, D. C., SMSA. Except for the data col-lected at the National Institutes of Health by Keyes on his ownpractice, no other data of this type are currently available.

“The data collection for the study was supported in part by agrant (grant No. H.S.-O2577) from the National Health Care Man-agement Center, Wharton School, University of Pennsylvania.That center IS funded by the National Center for Health ServicesResearch, Office of the Assistant Secretary for Health, DepartmentofHealth and Human Services.

IOA comparison of the data collected via mail and the data COl-lected by the dental students did not show any important statisticaldifferences. The data collected by the dental students were morecomplete.

"In some practices, we were able to complete questionnaires onmore than 10 patients; in others, we had to settle for fewer.

data for our estimates were collected on 190 pa-tients and over 800 dental visits. Approximately63 percent of the patients were female. The aver-age age of all patients was 42.

The Effectiveness ofthe Keyes Technique

In order to demonstrate the effectiveness orlack of effectiveness of the Keyes technology,five measures were used as general indicators ofperiodontal disease of the patients in the studybefore and after treatment. All five oral healthindicators showed some improvement followingtreatment (see table 1).

A number of the important indicatorschanged dramatically. Bleeding of gums uponprobing, an indication of early or beginningdisease, dropped from 99 percent of the patientsshowing it before treatment to 34 percent of thepatients showing it at the time the informationwas obtained. Another important change wasthe decrease from 65 to 9 percent in the numberof patients with loose teeth. This change is im-

Table 1 .—Periodontal Disease Indicators:Effectiveness or Lack of Effectiveness


Percentage of patients

Statusbefore Current

Indicator treatment status

1. Bleeding on probing . . . . . . . . . . . 99% 34%N = 185 N = 185

2. Suppuration. . . . . . . . . . . . . . . . . . 56 23N = 185 N = 181

3. Mobile teeth. . . . . . . . . . . . . . . . . . 65 9N = 178 N = 173

4. WBCS microscopically evident . . 9 4 78N = 182 N = 172

5. Motile forms microscopicallyevident . . . . . . . . . . . . . . . . . . . . . . 62 32

N = 170 N = 148

I2 ● Background paper #2 Case Studies of Medical Technologies

portant because loose teeth are an indication ofadvanced disease, A “t” test on the differencebetween the percentages before and after treat-ment for each of the periodontal disease indi-cators in table 1 was statistically significant atthe 0.01 level. Thus, these data indicate a sig-nificant overall improvement in dental healthfor our study population.

Moreover, at the time our study was done, 65percent of the 190 patients in the study popula-tion had gone from treatment to maintenance,and only 35 percent required further treatment.We also performed an analysis of the data overtime. This analysis included some of the patientsbeing treated and then maintained by the Keyesmethod for more than 24 months. *2 In these pa-tients, the indicators of oral health continued toshow almost the same level of improvement asin patients treated and maintained for less time.

Furthermore, our analysis of the data con-cerning the effect of the Keyes technology on thelevel of plaque control exercised by the patientsshowed that improvement in plaque control hadoccurred to the same extent as improvement inthe other indicators (see table 2). For example,before treatment 93 patients were judged tohave below-average plaque control, but at thetime our data were collected only 12 patientswere rated in this manner. A chi square testshowed patient improvement in plaque control(as indicated by the before and after data intable 2) for all groups of patients to be statis-tically significant at the 0.01 level or greater.(This finding does not apply to the group of pa-tients who were above average in plaque controlbefore treatment. )

12 The data used for this analysis are not presented in this discus-sion.

Table 2.—Plaque Control by Patients

After treatment

Patient status Above Belowbefore treatment average Average average

Above average (2). . . . . . . . 2 0 0Average (76). . , . . . . . . . . . 56 19 1Below average (93). . . . . . . 42 39 12

Total (171). . . . . . . . . . . . 100 58 13

The Delivery and Cost ofthe Keyes Technique

The Keyes technique involves the delivery of10 basic procedures. These procedures and thepercentage of patients in our study populationreceiving them during each visit to the dentistare shown in table 3. The first visit usually in-volves a dental history (76 percent) and a med-ical history (84 percent). If histories are not pro-vided during this visit, that usually indicatesthat histories were provided at a visit prior tobeginning the Keyes technique. This is also thecase for radiographs and visual assessment.During the first visit, over half the patientsundergo periodontal probing (7 I percent), amicroscopic examination (64 percent), and ascaling (52 percent). About two-fifths of the pa-tients receive periodontal pocket measurements(40 percent) and almost one-sixth (16 percent)receive root planing. Almost two-thirds of thepatients (64 percent) also receive plaque controlinstruction during the first visit.

The percentage of patients receiving dentalhistories, medical histories, and radiographs, asexpected, declines after the initial visit. Over thenext two visits (visits 2 and 3), the percentage ofpatients receiving root planing and scaling in-creases. Later visits continue the use of scalingand root planing, as well as plaque control in-struction and probing. The maintenance visitshows some increase in visual assessment, scal-ing, pocket measurement, and microscopic ex-aminations. Clearly, the maintenance visit (ex-cept for the histories, diagnosis, and plaque con-trol instruction) is somewhat similar to the ini-tial visit in terms of the procedures performed.

To estimate the cost of producing the Keyestechnique, we began with data on the amount ofdentist and hygienist time used during each visit(see table 4). The majority of this time is used toinstruct the patient in plaque control and pro-vide maintenance. The first visit uses an averageof 28 minutes of dentist time and 24 minutes ofhygienist time. ’3 For later visits (visits 5 and 6,

13 lt is interesting to note that the estimate of the average dentisttime has a large standard deviation in comparison to the mean (co-efficient of variation). A further analysis of the data showed thatthere was a significant variation among the 18 dental practices, aswell as across the patients treated within each practice.

Case Study #5: Periodontal Disease: Assessing the Effectiveness and Costs of the Keyes Technique ● 13

Table 3.—Mix of Services Delivered at Each Visit for the Keyes Technique

Percentage of patients (N)Maintenance

Service Visit 1 Visit 2 Visit 3 Visit 4 Visit 5 Visit 6 visitDental history. . . . . . . . . . . . . . . . . . . . 76%

N = 184Medical history. . . . . . . . . . . . . . . . . . . 84

N = 184Radiographs. . . . . . . . . . . . . . . . . . . . . 71

N = 184Visual assessment. . . . . . . . . . . . . . . . 97

N = 184Periodontal probing. . . . . . . . . . . . . . . 71

N = 185Pocket measurement . . . . . . . . . . . . . . 40

N = 185Microscopic examination . . . . . . . . . . 64

N = 185Scaling . . . . . . . . . . . . . . . . . . . . . . . . . 52

N = 184Root planing . . . . . . . . . . . . . . . . . . . . . 16

N = 185Plaque control instruction . . . . . . . . . 64

N = 185Other . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

N = 185

1 %

N = 1776

N = 17710

N = 17771

N = 17762

N = 17720

N = 17762

N = 17763

N = 17733

N = 17772

N = 17630

N = 176

1 %

N = 158

N =61587

N = 15871

N = 15860

N = 15817

N = 15854

N = 15866

N = 15835

N = 15854

N = 15736

N = 157

0N = 135

6%N = 135

N =713570

N = 135

N=99 14

N = 13546

N = 13562

N = 13528

N = 13544

N = 13533

N = 135

0N =99

4 %N =99

5N = 100

67N =99

47N =99

12N = 100

47N =99

N = 6 9

N =1OO37

N = 10023

N = 100

0N =69

1%N =69

14N =69

67N =69

45N =69

19N =69

51N =69

68N =69

32N =69

38N =69

22N =69

4%N = 105

N 10514

N = 10584

N = 10551

N = 10532

N = 10554

N = 10483

N = 10536

N = 10526

N = 10535

N = 105

N = number of observations.

Table 4.—Average Dentist and Hygienist Time Used for Each Visit for the Keyes Technique

MaintenanceVisit 1 Visit 2 Visit 3 Visit 4 Visit 5 Visit 6 visit

Dentist timea. . . . . . . . . . . . . . . . . . . . 28 22 20 21 19 22 20SD=22.46 SD=19.83 SD=18.1O SD=19.00 SD=16.84 SD=18.17SD=17.56

N = 173 N = 138 N = 135 N = 111 N =93 N =50 N =92Hygienist timea. . . . . . . . . . . . . . . . . . 24 25 23 23 21 21 21

SD= 22.43 SD= 19.20 SD= 19.99 SD= 19.28 SD= 19.27 SD= 19.72 SD= 18.25N = 140 N = 143 N = 117 N =99 N =69 N =53 N =83

SD= Standard deviationN = mumber of observations.aTime in minutes.

and the maintenance visit), the amount of den-tist time in each visit declines, while amount ofhygienist time remains quite stable. (For pur-poses of our cost calculation, we assumed thatthe dentist time is spent with only one patient.However, it is likely that some dentists are treat-ing more than one patient at a time. If that is thecase, our estimates of the average variable costof production may be too high. )

To estimate the average variable cost (in 1979dollars) of producing the Keyes technique, weassume that the dental practice is already inoperation and that the only additional expensesfor producing the Keyes technique are the costof the phase-contrast microscope and the cost of

the dentist and hygienist time.14 The scope costis about $3,000, and we depreciate it over a 10-year period. For the purpose of our estimates,we allocate the cost of the scope to 100 patientsbeing treated by the Keyes technique per year at$3 per visit.15 The cost of dentist time, based onthe yearly income of and hours worked by a

14 In a technical sense, once the scope is purchased, it is a fixedcost and not a variable cost. Since the cost of the scope is modest,deleting the cost from our estimate would have very little impact.

15 This estimate may be high, because dentists who use the Keyestechnique probably treat more than 100 patients a year. In anyevent, the per unit cost of using the phase-contrast microscope issmall; thus, alternative methods of computing its cost will have asmall impact on our estimates.

general practitioner, is estimated at $25 per hour(3). ” To estimate the cost of hygienist time, weused the same costing procedure and added iS

percent for fringe benefits. This produced a costof $8 an hour for the hygienist time (3).17

To produce an estimate of the labor cost pervisit, we applied these hourly rates to theminutes of time used by the dentist and hygien-ist. To this estimate, $3 was added for the use ofthe phase-control scope to produce estimates ofthe average variable cost of producing each visit(see table 5). According to our estimates, theaverage variable cost of producing the initialvisit is higher than that of producing subsequentvisits. The difference in average variable costmostly reflects the reduction of time spent bythe dentist and the different range of servicesprovided following the initial visit (table 4).

Data from our survey on the average chargefor each visit are presented in table 5. Again it isinteresting to note that the average charge ishighest for the initial visit. Moreover, for the

maintenance visit, the average variable cost as apercentage of average charge is the lower than itis for any of the first six visits. For the dentiststhat charge for the Keyes technique on the basisof the total treatment cost, the average chargeper case was slightly over $120. This charge percase is comparable to the total charge, on a pervisit basis, of between five and six visits.

In addition to paying the dental charges forthe Keyes technique, the patient needs to pur-chase an electric toothbrush and electrical irri-gating device at a total cost of $30 to $40. Inabout half the cases treated by the Keyes tech-nique in our data base, drugs were utilized, usu-ally tetracycline. The cost for tetracycline perprescription is between $8 and $10. In most in-stances, one or two prescriptions are requiredfor those patients using tetracycline. It is cur-rently believed that after the patient has beentreated successfully by the Keyes technique, twomaintenance visits at an average charge ofabout $26 per visit are required to ensure con-tinued oral health (29).

The Keyes technique may have benefits in ad-dition to the treatment and prevention of peri-odontal disease. In some patients, a benefit maybe a reduction in tooth loss. Furthermore, if sur-gery is avoided, the pain and discomfort asso-ciated with surgery are also avoided. By involv-ing patients in improving their oral health, theKeyes technique may improve their awarenessof dental disease and encourage their early useof dental services, while the disease is still treat-able, often at a reduced cost.

Table 5.— Estimates of the Average Variable Cost of Producing Each Visit andthe Average Charge per Visit for the Keyes Technique

CONCLUSION

Periodontal disease is a chronic disease thataffects over 90 percent of the adult population inthe United States (6, 15,16,22,29). Today, treat-ment of periodontal disease by dentists often in-volves surgery. The surgical procedures that areused may be painful to the patient, and theyoften carry with them postsurgical discomfort.More importantly, our assessment of the scien-tific literature shows that the effectiveness of thesurgery alone in the treatment of periodontaldisease has not been adequately demonstrated.

The Keyes technique is so new that long-termefficacy and effectiveness studies have not beenpossible, although the evidence to date appearspromising. Our analysis, based on data from 18

general practices in the Washington, D. C.,SMSA on 190 patients being treated with theKeyes technique and over 800 visits, found ameasurable and statistically significant im-provement in each of the five indicators of den-tal disease we employed. However, before moredefinitive conclusions on the effectiveness of theKeyes technique can be drawn, a more completeand longitudinal study is required.

Using our data base, we estimated the averagevariable cost of producing the Keyes techniquefor 190 patients representing over 800 patientvisits. The estimated average variable cost of avisit in 1979 was between $17.87 and $13.72, de-pending on whether it was an initial, followup,or maintenance visit. These average variablecost figures should be viewed as only rough esti-mates, and by definition they omit the fixed costof production (e. g., rent). By contrast, the re-ported charges in 1979 for the initial visit andthe maintenance visit for patients being treated

with the Keyes technique averaged $31.63 and$27.83, respectively. Given the charge data onvisits, our average variable cost figures appearto be quite reasonable estimates.

The cost effectiveness of the Keyes technique,if i t does have a long-term effectiveness, de-pends in part on the amount of periodontal sur-gery that is avoided. Although we are currentlyunable to estimate this amount or to obtain anestimate from the published literature, the den-tists in our study indicated that only between Oand 5 percent of patients being treated with theKeyes technique also required a referral to aperiodontist. If this estimate is correct and gen-eralizable, then the potential savings of theKeyes technique are large.

Our assessment of the literature on the effec-tiveness of periodontal surgery suggests thatfurther long-term clinical studies are needed.Such studies would be quite useful if they weredesigned to compare the Keyes technique toperiodontal surgery and included a controlgroup which did not receive either treatment.The patients under study should be randomlyassigned to each of these three groups. The ran-dom assignment of patients into a nontreatmentgroup raises an important ethical issue. How-ever, our assessment of the current method oftreating periodontal disease raises serious ques-tions about its effectiveness, so the assignmentof patients to a nontreatment group, with theirinformed consent, may be feasible. The costs ofeach of these alternatives—periodontal surgery,the Keyes technique, and no treatment—shouldbe computed and compared.

16 ● Backround Paper #2: Case Studies of Medical Technologies

APPENDIX A.–GLOSSARY OF DENTAL TERMS

Calculus.—Calcium phosphate and carbonate withorganic matter deposited upon the surfaces of theteeth.

Cementum.—The bonelike connective tissue cover-ing the root of a tooth and assisting in tooth sup-port.

Gingiva. —Gum of the mouth.Gingivitis.–Inflammation of the gingiva (gum) only.Keyes technique.—A nonsurgical method of treating

periodontal disease which involves microscopicdetermination of the microbial status, the applica-tion of certain salt solutions in all instances, peri-odic courses of systemic antibiotics when indi-cated, and an extensive regimen of oral hygiene in-struction.

Maintenance.— Patient seen periodically for assess-ment of periodontal health status, cleaning (pro-phylaxis), microscopic assessment of bacterial ac-tivity, and oral hygiene instruction if needed.

Mobile teeth. —Loose teeth.Mucogingival surgery. —Surgical removal of pockets

involving soft tissue only as part of the surgical ap-proach to treating periodontal disease.

Osseous surgery .—Surgical removal of bone as partof the surgical approach to treating periodontaldisease.

Quadrant. -A term used for descriptive purposes todesignate any one of four areas of the teeth andgums (e.g., the upper right quadrant or the lowerleft quadrant).

Periodontal disease.—Diseases of the supportingstructures of the teeth (e. g., gingivitis, periodon-titis),

Periodontist. —A dental specialist who concentrateson periodontal disease.

Periodontitis. —Inflammation of the supportingstructures of the teeth including bone, The use ofthis term connotes destruction of the periodontaltissues.

Periodontium. —The tissues investing and supportingthe teeth, including the cementum, periodontal lig-ament, alveolar bone, and gingiva.

Plaque.—A gummy, almost exclusively bacterialsubstance which adheres to the teeth and is dis-cernible only by applying stains, Plaque is the pri-mary causative agent in periodontal disease.

Pocket.—The deepening of the normal space be-tween the gum and the tooth due to inflammation.

Probing.—Placing a dental instrument under the gin-giva or gum to determine whether or not bleedingwill occur and to measure periodontal pockets, ifpresent,

Prophylaxis.—The use by professionals of appropri-ate procedures and/or techniques to clean theteeth.

Radiograph.—A film of internal structures of themouth produced by X-ray.

Root planing. –Smoothing of the root surfaces of theteeth using certain instruments.

Scaling. —Removal of calculus material from thetooth surfaces and that part of the teeth covered bythe marginal gingiva.

Sulcus.—The normal space between the gum and thetooth,

Case Study #S Periodontal Disease Assessing the Effectiveness and Costs of the Keyes Technique ● 17

APPENDIX B.–QUESTIONNAIRE USED TO COLLECT DATA

Dentist Age Years in Practice

1. Approximate length of time you have been using the Keyes technique:Years

2 .

5.

6.

7.

For approximately how many patients have you used the Keyes technique?P a t i e n t s

Do you use the Keyes technique as a preventive method as well as a t r ea tmen tmethod?

Yes No

Approximately what percentage of the patients with whom you have been usingthe Keyes technique also require some form of periodontal surgery?

o-5% 5 - l o % 10-20% 20-30%

How much do you refer patients to periodontists now as compared to beforeyou began to use the Keyes technique?

More Less Same

Considering all of your patients that have been treated by the Keyestechnique, approximately what percentage do you consider to have beent r e a t e d :

% Successfully % Unsuccessfully

What do you believe are the principal reasons for lack of success?(Use the back of this page if necessary.)

8. Would you be willing to allow me to ask the patients on whom you havecompleted a quest ionnaire to answer a few quest ions about their feel ings?

Yes No

9. If yes, please sign your name:

I8 Background Paper #2: Case Studies of Medical Technologies

P a t i e n t Age sex

Address

Date patient began treatment with Keyes technique Today's Date

Total number of visits for the Keyes technique made by patient to date

Total number of maintenance visits to date

A t I n i t i a l V i s i t

PERIODONTAL STATUS(Please check where appropriate)

At This Time

Healthy, on maintenance care onlyGingival inflammation onlyBleeding on probingSuppurationRadiographic evidence of bone lossNumber of mobile teethNumber of quadrants of involvementMicroscopic - many WBC'sMicroscopic - many motile forms

ASSESSMENT OF PATIENT’S PLAQUE CONTROL

Above average (doing well on own)Average (needs some professional instruct ion)Below Average (needs a great deal ofp ro fe s s iona l i n s t ruc t i on )

Approximate total number of hours of plaque control instruction givenBy whom: Den t i s t

Hygienis tDental Assis tant

Frequency of prophylaxis times per year

USE OF ANTIBIOTICS TO TREAT THE PATIENT

Yes No

I f y e s , h o w l o n g w a s e a c h c o u r s e ? -weeks. How many courses?

PATIENT USES:(please check correct response)

Baking soda and peroxideF l u o r i d eI r r i g a t i o nOthe r , p l ea se i nd ica t e

Yes NoYes NoYes NoYes No


prior to seeing you?Has this patient been treatedYes No— —

for per iodontal disease

If yes , was i t by a general dent is t o r a p e r i o d o n t i s t ?

PLEASE CHECK WHICH PROCEDURES ARE DONE AT EACH VISIT FOR THIS PATIENTUSING THE KEYES TECHNIQUE

VISITS1st 2nd 3rd 4th 5th 6th Maintenance

Dental historyMedical historyRadiographsVisual assessmentPeriodontal probingPocket measurementMicroscopic examinationScalingRoot planingP laque con t ro l i n s t ruc t i onOther ( l i s t )Other ( l i s t )

PATIENT USING THE KEYES TECHNIQUEPLEASE ANSWER THE FOLLOWING FOR THIS

1. Average chair time perpa t i en t v i s i t (minu te s )

2. How many minutestime was with:

Den t i s tHygienis t

o f t h i s

Dental Assis tantO t h e r ( s p e c i f y )

3. Approximate cost topat ien t per vis i t

$ — $ — $ — $ — $— —$$ —

4. If cost w a s on the basis of a total case, what was the cost per case? $

5. What was the average charge to patient for maintenance visit? $

COMMENTS

If you feel that these quest ions wil l not show the correct information aboutei ther effect iveness or cost using the Keyes technique for this pat ient , pleasesupply the information you believe will help on the back of this page.

20 . Background Paper #2: Case Studies of Medical Technologies

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

15.

“Agents for the Control of Plaque: A Sym-posium Presented at the Meeting of the Interna-tional Association for Dental Research, ” J. Dent.Res. 58:2378, 1979.American Dental Association, Bureau of Eco-nomic Research and Statistics, “Dental FeesCharged by General Practitioners and SelectedSpecialists in the United States, 1977, ” J. Am.Dent. Assoc., October 1978.

T h e 1 9 7 7 S u r v e y o f D e n t a l P r a c t i c e s

( O @ & : A D A , 1 9 7 7 ) .Axelson, P., and Lindhe, J., “Effect of Con-trolled Oral Hygiene Procedures on Caries andPeriodontal Disease in Adults, ” J. Clin. Peri-odont. 5:133, 1978.

“The Effect of a Preventive Programmeon Dental Plaque, Gingivitis, and Caries inSchoolchildren: Results After One and TwoYears,” ]. Clin. Periodont. 1:126, 1974.Chilton, N. W., and Miller, M. F., “Epidemiol-ogy of Periodontal Disease: Position Report andReview of Literature, ” in International Con-ference on Research in the Biology of Periodon-tal Disease (Ann Arbor, Mich.: University ofMichigan, 1977).Cohen, D. W., “Role of Periodontal Surgery,”).Dent. Res. 50:212, 1971.Committee Report, in lnternational Conferenceon Research in the Biology of Periodontal Dis-ease (Ann Arbor, Mich.: University of Michi-gan, 1977).Committee Report: “The Etiology of Periodon-tal Disease, ” in World Workshop in Periodon-tics, S. P. Ramfjord, et al. (eds. ) (Ann Arbor,Mich.: University of Michigan, 1966).Douglass, C. N., and Day, J. M., “Cost andPayment of Dental Services in the UnitedStates,” J, Dent. Educ. 43(7) :33o, 1979.Garrett, J. S., “Root Planing: A Perspective, ” J.Periodont. 48:553, 1977.Gibson, R. M., “National Health Expenditures,1978, ” Health Care Fin. Rev. 1(1), summer 1979.Henry, J. L., and Sinkford, H. C., “The Eco-nomic and Social Impact of Periodontal Disease:Position Report and Review of Literature, ” in In-ternational Conference on Research in the Biol-ogy of Periodontal Disease (Ann Arbor, Mich.:University of Michigan, 1977).Hurt, W. C., “Periodontal Diagnosis–1977: Astatus Report, ” J. Periodont, 48:533, 1977.Ingle, J. I., “The Health, Economic, and CulturalImpact of Periodontal Disease on Our Aging

16.

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Population, ” presented at the National Institutesof Health Conference on Aging, Louisville, Ky.,1975.Kelly, J. E., and VanKirk, L. E., “PeriodontalDisease in Adults: United States 1960-62, ” PHSpublication No. 10 (Washington, D. C.: U.S.Government Printing Office, 1965).Keyes, P. H., et al., “The Use of Phase-ContrastMicroscopy and Chemotherapy in the Diagnosisand Treatment of Periodontal Lesions—An Ini-tial Report (I), ” Quintessence lnternat. 1:5I,1978.

“The Use of Phase-Contrast Microscopyand Chemotherapy in the Diagnosis and Treat-ment of Periodontal Lesions—An Initial Report(II), Quintessence lnternat. 2:69, 1978.Lee, H., et al., “Experimental Gingivitis, ” Man.J. Periodont. 36;177, 1965.Loesche, W. J., “Chemotherapy of DentalPlaque Infections, ” Oral Sci. Rev. 9:63, 1976.Pennel, B. M., and Keagle, J. G., “PredisposingFactors in the Etiology of Chronic InflammatoryPeriodontal Disease, ” J. Periodont. 48:517,1977.Periodontal Disease and Oral Hygiene AmongChildren, DHEW publication No. (HSM) 72-1060 (Washington, D. C.: Department of Health,Education, and Welfare, 1972).Ramfjord, S. P., “Surgical Pocket Therapy,”Int. Dent. J. 27;263, 1977.Ramfjord, S. P., et al., “Longitudinal Study ofPeriodontal Therapy, ” J. Periodont. 44:66,1973.Ranney, R. R., “Pathogenesis of PeriodontalDisease: Position Report and Review of Litera-ture, ” in International Conference on Researchin the Biology of Periodontal Disease (Ann Ar-bor, Mich.: University of Michigan, 1977).Rosling, B., et al., “The Effect of SystemicPlaque Control on Bone Regeneration in Infra-bony Pockets, ” J. Clin. Periodont, 3:38, 1976.

“The Healing Potential of the Periodon-tal Tissues Following Different Techniques ofPeriodontal Surgery in Plaque-Free Dentitions, ”J. Clin. Periodont. 36:233, 1976.Rovin, S., “A Curriculum for Primary CareDentistry, ” J.E. D. 41:176, 1977.Sheiham, A., “Prevention and Control of Peri-odontal Disease, ” in International Conferenceon Research in the Biology of Periodontal Dis-ease (Ann Arbor, Mich,: University of Michi-gan, 1977).

Case Study #.5 Periodontal Disease: Assessing the Effectiveness and Costs of the Keyes Technique ● 21

30.

31.

32.

Soransky, S. S., “Microbiology of PeriodontalDisease—present Status and Future Considera-tions, ” J. Periodotlt. 48:497, 1977.Suomi, J. D., et al., “The Effect of Controlled 33.Oral Hygiene Procedures on the Progression ofPeriodontal Disease in Adults: Results AfterThird and Final Year, ” J. Periodont. 42:152,1971. 34.Tanzer, J. M., “Microbiology of PeriodontalDisease: Position Report and Review of Liter-

ature, ” in International Conference on Researchin the Biology of Periodontal Disease (Ann Ar-bor, Mich.: University of Michigan, 1977).U.S. Department of Health, Education, andWelfare, “Edentulous Persons, United States, ”National Center for Health Statistics, series 10,No. 89, 1971.Zander, H. A., and Poison, A. M., “PresentStatus of Occlusion and Occlusal Therapy inPeriodontics, ” J. Periodont. 48:540, 1977.

Commentary

Editor of Commentary:

AlIan J. Formicola, D.D.S.Dean, School of Dental and Oral Surgery

Columbia University

Authors:

R. Gottsegen, D.D.S.Professor of Dentistry

Director of PeriodonticsSchool of Dentistry

Columbia University

S. Socransky, D.D.S.Senior Staff MemberHead of Periodontics

Forsyth Dental Center

J. Hay, Ph. D.Assistant Professor

School of Dental MedicineUniversity of Connecticut

Page

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

Diagnosis of Periodontal Disease and Monitoring of Disease Activity . . . . . . . . . . 26Are the Samples Representative? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Is the Test Diagnostic of Disease Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

The Use of Salt, Hydrogen Peroxide, Sodium Bicarbonate, andTetracyclineas Therapeutic Agents in the Control of Periodontal Disease and the Useof PhaseMicroscopy as a Patient Motivator . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Economic Perspectives. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Commentary

Editor of Commentary:

AlIan J. Formicola, D. D.S.*Dean, School of Dental and Oral Surgery

Columbia UniversityNew York, N.Y.

INTRODUCTION

Periodontal disease is ubiquitous, affecting 80to 90 percent of the adult population. It mayrange from simple gingivitis to advanced de-structive periodontitis in which there is destruc-tion of the supporting tissues around the teeth,resulting in tooth loss.

Treatment of early, or mild, periodontal dis-ease is usually simple, short, and successful.Treatment of advanced periodontitis, thoughmore involved and protracted, has a high suc-cess rate. Further, treatment is based on thelong-term experience of many expert cliniciansand observers, supported by sound clinicalresearch.

The criteria for a clinical investigation to beconsidered as having scientific merit are thefollowing: I) the use of reliable and standard-ized measurements; 2) adequate controls, par-ticularly in clinical trials; 3) presentation of datain a form allowing appropriate statistical anal-ysis; and a) submission of reports to peer review

*In addition to Dr. Formicola, the primary authors of this com-mentary are: R. Gottsegen, Professor of Dentistry, Director ofPeriodontics, School of Dentistry, Columbia University; S. So-cransky, Senior Staff Member, Head of Periodontics, ForsythDental Center; and J. Hay, Assistant Professor, School of DentalMedicine, University of Connecticut.

The authors gratefully acknowledge the contributions of thefollowing individuals: John J. Bergquist, Professor and Chairmanof Periodontics, University of Maryland; R. Caffesse, Professorand Chairman of Periodontics, School of Dentistry, University ofMichigan; D. Fine, Associate Professor of Dentistry, School ofDentistry, Columbia University; P. Kamen, Assistant Professor ofDentistry, School of Dentistry, Columbia University; J. Kennedy,Professor of Dentistry and Dean, School of Dentistry, VirginiaCommonwealth University; A. Poison, Chairman of Periodontics,Eastman Dental Center, and Associate Professor, University ofRochester; and R. Rosenberg, Assistant Clinical Professor, Schoolof Dentistry, Georgetown University.

by publication in scientific journals. Studies notadhering to these standards are not scientificallyvalid, and their results must be considered anec-dotal. Scheffler and Rovin’s study of the Keyestechnique in 18 dental practices in the Washing-ton, D. C., area does not adhere to these stand-ards.

However, there is in the scientific literatureabundant well-documented evidence thatplaque removal and subsequent control arrestsor reverses gingivitis and early periodontitis.Since the Keyes technique relies principally onplaque removal and control, it is not a newtechnique at all, for plaque removal and controlare exactly what all dentists who treat periodon-tal disease do as the initial and basic part of theirtherapy.

For hundreds of years, periodontal treatmenthas been based on the removal of hard and softdeposits from tooth surfaces. This therapy hasbeen quite effective. However, cases of ad-vanced periodontal disease may require the useof surgical procedures for the proper debride-ment of inaccessible microbial masses and cal-culus. The depths of periodontal pockets orother difficult to reach places cannot be thor-oughly cleansed unless exposed surgically. In-deed, root surfaces with periodontal pocketsdeeper than 5 mm may still harbor significantnumbers of micro-organisms despite carefulscaling by skilled operators (12). A further bene-ficial effect of the surgical approach may be toreduce pocket depth, thus making formerly in-accessible areas accessible for the patient to ex-ercise plaque control.

25


A study of the result of conventional therapywas reported by Hirschfeld and Wasserman in1978 (l). This study involved 600 patients, mostof whom had advanced periodontal disease. Allthese patients had been referred to a periodontalspecialist for care because they were in immi-nent danger of losing teeth. All 600 receivedconventional periodontal treatment, which formany included surgery when indicated; and allthen had followup care for 15 to 50 years (with amean duration of observation of 22 years).Eighty-three percent of these patients lost only Oto 3 teeth. The fact that these patients with ad-vanced disease lost so few teeth during that longtime span demonstrates the success of conven-tional periodontal therapy. However, a smallsubgroup of 25 patients (4.2 percent) in thisstudy lost more than 10 teeth in the 22-year fol-lowup period. Recent evidence from other stud-ies suggest that this subgroup of patients prob-ably had a more aggressive or rapidly progress-ing form of adult periodontitis.

It should be noted that the Hirschfeld andWasserman study did not include patients withsimple gingivitis or early periodontitis; thestudy examined only the results of conventionaltreatment of patients with advanced periodontaldisease. No similar conclusions regarding the ef-fectiveness of the Keyes technique in the treat-ment of advanced periodontal disease can bedrawn from the study by Scheffler and Rovinfor two reasons. One, the authors provide nouseful information indicating the severity of thepatients’ disease, and two, their study is of suchshort duration that it is valueless for judging thelong-term effect of the Keyes technique on ad-vanced periodontal disease.

There are other careful long-term studieswhich have demonstrated the long-term successof conventional treatment: Ramjford, et al. (7),Knowles, et al. (3), Lindhe and Nyman (4), andNyman and Lindhe (6). These studies followedthe patients for periods of time up to 10 yearsafter treatment. Treatment was careful prepara-tion of the patient by scaling, plus motivationand training in oral hygiene. Surgery was indi-cated because of the severity of the patients’periodontal disease.

All of these studies constitute strong evidencethat conventional periodontal therapy, includ-ing surgery and proper maintenance by the den-tist and the patient, can stop the progress of ad-vanced periodontal destruction and maintainthe dentition in the majority of cases.

When comparing these well-designed studiesof conventional treatment that have been re-ported in the scientific literature to the study ofthe Keyes technique by Scheffler and Rovin, onemust point out that the Keyes technique in-volves the same antimicrobial approach as con-ventional therapy. However, Keyes only rarelyaccepts the use of surgery to gain access to moredeeply involved areas. His method is to flushsuch areas with salt solutions, which, he states,is sufficient to kill pathogenic bacteria. Whethersalt solutions actually achieve this goal is notclear at this time. Thus, it is premature to sug-gest that this treatment regimen alone should beused in human patients as a replacement fortechniques that have been documented to con-trol periodontal diseases.

DIAGNOSIS OF PERIODONTAL DISEASEOF DISEASE ACTIVITY

AND MONITORING

The Keyes technique employs a diagnostic tions: 1) that the microbiologic samples takentest that has not yet been validated as a measure are representative of the microbiota (bacterialof disease activity, namely, phase-microscopic population) in the worst-diseased sites, andexamination of wet samples of material scooped 2) that the test is diagnostic of disease activityout of periodontal pockets. Implicit in reliance and can also be used to monitor the effects ofon this test are at least two unproved assump- treatment.


Are the Samples Representative?The basis of choosing the sites for sampling of

subgingival plaque has not been clearly definedby Keyes, apart from a statement that “particu-lar effort is made to obtain samples from deepersubgingival spaces that are difficult for the pa-tient to clear (sic)” (2). That the samples arerepresentative is an unwarranted assumption,because there is a dramatic variation in the bac-terial population from site to site within thesame individual, from supragingival (above thegum margin) sites to subgingival (below thegum margin) sites, from diseased sites to healthysites, and between sites with different forms ofperiodontal disease (5,8,9,10). Therefore, thereis no basis for using a sample of bacteria fromone area as an indication of the bacterial pop-ulation of the plaque from a patient’s mouth.

Is the Test Diagnostic ofDisease Activity?

Any proposed diagnostic test must be vali-dated. The one used in the Keyes technique hasnot been. Keyes’ claim that the state of diseaseactivity can be determined by examining the

proportion of motile forms on a microscopicslide is not substantiated by scientific evidence.Research on the possible existence of such a rela-tionship is just now being invited in a “Requestfor Proposals” issued by the National Institutesof Health (RFP No. NIH-NIDR-81- 3R).

However, there is at this time a limitedamount of established knowledge about the re-lationship of motile organisms and periodontaldisease. That phase microscopy could be sen-sitive to all forms of active periodontal destruc-tion is doubtful. For example, in the case of peri-odontosis, an actively progressive periodontaldisease that causes major destruction of bonesurrounding the teeth in young individuals,there are few motile organisms even though thedisease is progressing at a rate generally consid-ered to be much faster than that of adult perio-dontitis. The organism that has been shown tobe uniquely and closely associated with thiscondition is not motile.

Thus, it seems clear that to date there is noconvincing rationale for the use of phase micro-scopy for either of the two uses suggested byKeyes.

THE USE OF SALT, HYDROGEN PEROXIDE,SODIUM BICARBONATE, AND TETRACYCLINE AS THERAPEUTICAGENTS IN THE CONTROL OF PERIODONTAL DISEASE ANDTHE USE OF PHASE MICROSCOPY AS A PATlENT MOTIVATOR

A widespread group of therapeutic modalitiesis employed in the Keyes technique. One modal-ity is scaling, which as stated above has beenshown to be effective in controlling periodontaldisease. In addition, Keyes advocates local ap-plications of concentrated salt solutions and/orpastes of sodium chloride, magnesium chloride,hydrogen peroxide, and often the systemic ad-ministration of tetracycline (an antibiotic) undercertain conditions. At present, tetracycline hasbeen shown to be needed in only a small numberof cases which responded poorly to routine ther-apy. The use of this drug in about half of the pa-tients treated by the Keyes followers in Schefflerand Rovin’s Washington area study is totally

unjustified. Furthermore, no evidence is avail-able which suggests that the local applicationsof salt solutions or pastes or hydrogen peroxidereduce the rate of periodontal destruction, pre-vent the recurrence of active periodontal lesionsin a treated patient, or add anything to the ex-isting regime of periodontal therapy.

Keyes and followers assert that phase micros-copy has value in motivating a patient to per-form proper oral hygiene. This assertion isbased on the assumption that patients are morewilling to follow the dentist’s directions to cleantheir mouths properly when shown the livingbacteria which can be scraped off their teeth.


However, the American Society of Preventive tients, found that the technique does not pro-Dentistry, which in the 1960’s spearheaded an vide a better approach to patient motivationeffort to use phase microscopy to motivate pa- than traditional modes of hygiene instruction.

ECONOMIC PERSPECTIVES

CBAS and CEAS of medical-dental proceduresare essentially accounting procedures carriedout to determine if a given program, or in thiscase a treatment regimen, is worth the effort.These analytic techniques have become increas-ingly sophisticated in the last 5 years (11,13).CBA relates the total costs of receiving suchtreatment to the total benefits, while CEA com-pares the costs of one treatment modality tothose of another, or to a group of alternativetreatments, having established that all of thetreatments meet a minimum acceptable level ofeffectiveness.

Scheffler and Rovin do not present a completepicture of costs and benefits nor of the costs ofalternative treatments. Although they discussalternative surgical and nonsurgical techniques,they do not present the types of data necessaryto compare these alternatives with the Keyestechnique.

The only costs that Scheffler and Rovin pre-sent are certain average variable labor and

SUMMARY

Researchers can point to mounting evidencethat dentistry is gaining the scientific knowledgethat will provide the public some measures forthe prevention and management of periodontaldisease. Dentistry has repeatedly demonstratedits willingness to support major public health ef-forts. Dental researchers and practitioners haveactively participated in the development of thescientific base, clinical applications, and pro-motion of measures to control dental cariesthrough the use of fluoride and, more recently,sealants. Now the dental research community isseeking to conquer caries totally by developinga caries vaccine. Research towards this goal isbeing carried out at a number of research

capitalfigures

costs of dental office visits. Even theseare inconclusive. The authors’ data are

not clear and do not specify whether all of thedentists were providing the same mix of dentalservices. Their cost estimates might differ con-siderably if periodontists or general practi-tioners proficient in periodontal surgery wereincluded in the data sample.

A more glaring deficiency, which the authorshave acknowledged by disclaimer, is the lack ofany estimates of patient opportunity costs, bothin the dental office visits and in home oralhygiene. Generally speaking, patient opportuni-ty costs would capture the value of resourcesconsumed by the patient in addition to dentaloffice charges. These costs would include trans-portation costs to visit the dentist, time spent inhome oral hygiene, etc. They would also includedentist opportunity costs, e.g., the cost of train-ing personnel to carry out the Keyes regimen.

centers, supported cooperatively by universitiesand the National Institutes of Health.

While our scientific knowledge base for peri-odontal disease may lag behind that for caries,significant advances have been made in the lastdecade and a half by a diverse and dedicatedgroup of scientists and concerned clinicians.

We understand and sympathize with the goalof Dr. Keyes and coworkers as well as Drs.Scheffler and Rovin to provide better, simplerand less expensive therapy to all periodontal pa-tients, because this is a goal shared by all in-dividuals in periodontal research. However, thestandard for acceptance of therapy cannot


become enthusiastic advocacy, popular appeal,and press releases, but must be carefully con-trolled clinical and laboratory testing. Accept-

REFERENCES

1,

2.

3.

4.

5.

6.

Hirschfeld, L., and Wasserman, D., “A Long-Term Survey of Tooth Loss in 600 Treated Peri-odontal Patients, ” J. Periodont. 49:225, 1978.Keyes, P. H., et al., “The Use of Phase-ContrastMicroscopy and Chemotherapy in the Diagnosisand Treatment of Periodontal Lesions—An Ini-tial Report (I), ” Quintessence Internat. 1:51,1978.Knowles, J. W., et al., “Results of PeriodontalTreatment Related to Pocket Depth and Attach-ment Level: Eight Years, ” J. Periodont. 50:225,1979.Lindhe, J., and Nyman, S., “The Effect ofPlaque Control and Surgical Pocket Eliminationon the Establishment and Maintenance of Peri-odontal Health: A Longitudinal Study of Perio-dontal Therapy in Cases of Advanced Periodon-titis, ” J. Clin, Periodont. 2:67, 1975.Listgarten, M. A., and Hellden, L., “RelativeDistribution of Bacteria at Clinically Healthyand Periodontally Diseased Sites in Humans, ” J.Clin. Periodont. 5:115, 1978,Nyman, S., and Lindhe, J., “A LongitudinalStudy of Combined Periodontal and ProstheticTreatment of Patients With Advanced Periodon-tal Disease,” J. Periodont, 50:163, 1979.

ance of the former as standards would be as asharp step backward for the dental professionand for the public.

7.

8.

9.

10,

11.

12.

13.

Ramfjord, S. P., et al., “Longitudinal Study ofPeriodontal Therapy, ” J. Periodont. 44:66,1973.Slots, J., “Subgingival Microflora and Periodon-tal Disease, ” J, Clin. Periodont. 6:351, 1979.Socransky, S. S., “Microbiology of PeriodontalDisease—Present Status and Future Considera-tions, ” J. Periodont, 48:497, 1977.Syed, S. A., and Loesche, W. J., “Bacteriologyof Human Experimental Gingivitis: Effect ofPlaque Age, ” Infect. and Immun. 21:821, 1978.Thompson, M., Benefit-Cost Analysis for Pro-gram Evaluation (Beverly Hills, Calif.: SagePress, 1980).Waerhaug, J., “Healing of the Dento-EpithelialJunction Following Subgingival Plaque Control,II: As Observed on Extracted Teeth, ” J. Perio-dent. 49:119, 1978.Warner, K., and Luce, B., Cost-Benefit andCost-Effectiveness Analysis in Health Care:Principles, Practice and Potential (Ann Arbor,Mich.: Health Administration Press, in press,1981).

AUTHORS’ RESPONSE TO COMMENTARY

In his commentary, Dr. Formicola includesamong the criteria for evaluating a scientificclinical investigation the use of adequate controlgroups, and he further states that studies with-out such controls must be considered “anec-dotal. ” A control group in a clinical study isgenerally defined as a group of patients which iscomparable to the treatment group but whichdoes not receive the therapy that is to bestudied. However, the clinical studies of perio-dontal therapy that Dr. Formicola cites do notuse control groups; instead, they report the im-pact of the application of one therapeutic mo-dality or another. Thus, according to Dr.Formicola’s commentary, these studies shouldbe labeled “anecdotal. ”

Actually, the lack of control groups is a fun-damental problem found in most of the litera-ture on periodontal disease. Specifically, therehave been few controlled clinical studies inwhich a treatment group received periodontalprocedures and a control group received notherapy at all. The one major study that did usea control group (4) dealt with the use of oralhygiene procedures only; it did not include sur-gical procedures. That investigation was cited inour case study, but not in Dr. Formicola’s com-mentary.

There are no scientific studies which showthat the surgical approach to treating periodon-tal disease is any better than the conservativeapproach used by clinicians for many years. Ac-tually, a major recommendation in our casestudy is that such controlled clinical studies becarried out: “Our assessment of the literature onthe effectiveness of periodontal surgery suggeststhat further long-term clinical studies areneeded. Such studies would be quite useful ifthey were designed to compare the Keyes tech-nique to periodontal surgery and included acontrol group which did not receive either treat-ment .“

In his commentary, Dr. Formicola spoke atgreat length about the Hirschfeld and Wasser-man study (1) and suggested that it was an ex-ample of research with scientific merit. How-ever, it should be noted that in this study, pa-tient samples were not randomized nor selected

30

on any statistical basis; there were no controlgroups; and the same dentists who performedthe treatment also evaluated it. The Hirschfeldand Wasserman study was a retrospective anal-ysis of treatment and was not predicated on apredetermined treatment modality. Moreover,there was no rating reliability between the eval-uators. In fact, some of the patients were treatedby different dentists at different points in time.Finally, no statistical tests were used to analyzethe data.

However, even if we ignore these limitations,the evidence in the Hirschfeld and Wassermanstudy (1) points more to the retention of teethwithout periodontal surgery than it does toretention with surgery. Of the 600 patients inthe study, only 230 (39.3 percent) had periodon-tal surgery in the first place. According toHirschfeld and Wasserman, most of the patientsresponded just as well without surgery as withit: “. . . in the great majority of cases surveyed,simple but thorough treatment in the form ofsubgingival scaling, occlusal adjustment, andfair to good home care seemed to reduce toothloss.” The investigators concluded: “The mor-tality of teeth which were treated with periodon-tal surgery was compared with that of teethwhich did not have surgery. Tooth retentionseemed more closely related to the case typethan the surgery performed. ”

Although Dr. Formicola implies otherwise,the Hirschfeld and Wasserman study cannot beconsidered anything other than what he terms“anecdotal, ” for the reasons we have cited.Hirschfeld and Wasserman appropriately entitletheir study a survey, “A Long-Term Survey ofTooth Loss in 600 Treated Periodontal Pa-tients. ” This label is not to denigrate their effortbecause the effort did provide useful and impor-tant information.

Many of the other clinical studies cited by Dr.Formicola are deficient because dentists whoperformed the surgical therapy also evaluatedthe results; independent evaluations were usual-ly absent. The Ramfjord group of studies (3)had some standardization in that the same eval-uators were used throughout, but even in thesestudies, it is not clear in some cases whether the

dentists who performed the evaluation did notalso perform the surgery. An even more seriousdeficiency is the absence of a control group.

Thus, none of the clinical studies which werecited by Dr. Formicola conforms to his own cri-teria for scientific merit. Unfortunately, the clin-ical studies which occupy the bulk of the perio-dontal literature lack scientific rigor. But theseare the studies on which periodontal therapy ispredicated. To repeat, the need for randomizedcontrolled clinical studies of alternative treat-ments for periodontal disease is essential, sothat effective periodontal treatments can beidentified.

We find it disappointing that Dr. Formicolabelieves that cost-benefit analysis (CBA) andcost-effectiveness analysis (CEA) are “essential-ly accounting procedures, ” despite the effortthat OTA has made in explaining these con-cepts. According to OTA: “The terms CEA andCBA refer to formal analytical techniques forcomparing the positive and negative conse-quences of alternative ways to allocate re-sources” (2), OTA found no consensus amonganalysts and practitioners as to a standard set ofmethods for CEA/CBA (2). Accounting proce-dures have little, if anything, to do with the ana-lytical technique of CEA or CBA.

We conducted a CEA of the Keyes technique,but because there was no existing CEA of perio-dontal surgery, we could not compare the Keyestechnique to the surgical alternative. We didfind national data which show that surgery ismuch more expensive than the Keyes technique.Surgery on a single quadrant of the mouth coststhe patient an average of at least $250, whereassix visits for the Keyes program cost about $150.Thus, even without including the cost of follow-up treatments after surgery, the cost to the pa-tient is considerably higher when surgery is per-formed than when the Keyes technique is used.As Dr. Formicola points out, the costs of theKeyes technique would be different if periodon-tists performed it instead of general practicedentists. However, we see no reason to use thehigher wages of periodontists in our calculationsif general practice dentists can deliver the Keyestechnique.


warrant a long-term comprehensive investiga-tion. If the Keyes program should prove effec-tive in the long run, it could reduce the cost ofcontrolling periodontal disease and perhaps

REFERENCES●

1.

2.

Hirschfeld, L., and Wasserman, D., “A Long-Term Survey of Tooth Loss in 600 Treated Perio-dontal Patients,” ]. Periodorzt. 49:225, 1978.Office of Technology Assessment, U.S. Congress,The Implications of Cost-Effectiveness Analysisof Medical Technology, GPO stock No. 052-003-00765-7 (Washington, D. C.: U.S. Govern-ment Printing Office, August 1980).

allow the treatment of many more patients withperiodontal disease, as well as reduce theamount of periodontal surgery and its costs.

3.

4.

Ramfjord, S. P., et al.,Periodontal Therapy,” ].

“Longitudinal Study ofPeriodont. 44:66, 1973.

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* U S GOVERNMENT PRINTING OFFICE 1981 341 -844/1007