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A National Clinical Guideline for the Use of Dental Filling MaterialsInformation for Dental Health Care Personnel

Title: A National Clinical Guideline for the Use of Dental Filling Materials

Issued: 12/2003ISBN-nr. 82-8081-031-5

Published by: Directorate for Health and Social Affairs, NorwayContact: Department for Municipal Health and Social ServicesPostal address: Directorate for Health and Social Affairs Department for Municipal Health and Social Services P.O. Box 8054 Dep, 0031 OSLO NorwayVisiting address: Universitetsgata 2 Telephone: +47 24 16 30 00Telefax: +47 24 16 30 01Internett: www.shdir.no

Order from: Directorate for Health and Social Affairs Publications Officee-mail: trykksak@shdir.noTelephone: +47 24 16 33 68Order reference: IS-1136

A National Clinical Guideline for the Use of Dental Filling MaterialsInformation for Dental Health Care Personnel

2

H E A D I N G

3

The definitions of the types of evidence and the grading of recommendations used in this guideline originate from the US Agency for Health Care Policy and Research1 and are set out in the following tables.

Statements of evidence

Evidence obtained from meta-analysis of randomized controlled trials.

Evidence obtained from at least one randomized controlled trial.

Evidence obtained from at least one well-designed controlled study without randomization.

Evidence obtained from at least one other type of well-designed quasi-experimental study.

Evidence obtained from well-designed non-experimental descriptive studies, such as comparative studies, correlation studies and case studies.

Evidence obtained from expert committee reports or opinions and/or clinical experiences of respected authorities.

Assessment

In the assessment sections a description is given of the aspects and factors which were included in the assessment when the recommendations have been compiled on the basis of the summary of knowledge given above.

Grades of recommendations

Requires at least one randomized controlled trial as part of a body of literature of overall good quality and consistency addressing the specific recommendation. (Evidence levels 1a, 1b).

Requires the availability of well-conducted clinical studies but no randomized clinical trials on the topic of recommendation. (Evidence levels 2a, 2b and 3).

Requires the availability of well-conducted clinical studies but not randomized clinical trials on the topic of recommendation. (Evidence level 4).

Good practice points

Recommended best practice based on the clinical experience of the guideline development group.

1 US Department of Health and Human Services. Agency for Health Care Policy and Research. Acute pain management: operative or medical procedures and trauma. Rockville (MD): The Agency; 1993. Clinical Practice

Guideline No. 1. AHCPR Publication No. 92–0023. p. 107.

1 K E Y T O E V I D E N C E S T A T E M E N T S A N D G R A D E S O F R E C O M M E N D A T I O N S

1.1

1.4

1.2

1.3

Level 1a

Level 1b

Level 2a

Level 2b

Level 3

Level 4

Assessment

C O N T E N T S

1 Key to Evidence Statements and Grades of Recommendations 3

2 Foreword 5

3 Summary 6

4 Introduction 7

5 Evaluations and Recommendations 8

6 Overlying Principles and Regulations 13

7 Conclusions 16

8 The Situation in the Other Nordic Countries 17

9 Implementation, Evaluation and Updating 18

10 Development of the Guideline 19

11 The Evidence Base 21

12 Appendix 1: Central Working Group at the Norwegian Board of Health 32

13 Appendix 2: Reference Group 33

14 Appendix 3: Working Group at the Directorate for Health and Social Affairs 34

15 Appendix 4: Participants at the Meeting Held on 10 July 2002 35

16 Appendix 5: Participants at the Meeting Held on 14 February 2003 36

References 37

The Directorate for Health and Social Affairs, Norway, intends that this guideline will influence decisions on the use of dental filling materials. It is acknowledged that mercury is a problem in relation to the environment and there is increasing concern in the population about health risks due to the use of amalgam fillings.

Dental filling materials are classified as medical devices and are not required to undergo clinical trials prior to marketing. Development in this field is rapidly escalating. Before gaining sufficient experience with a new material, a new and allegedly improved version appears on the market. Health authorities wish to obtain a better overview in this field and the guideline represents the first step in this direction. Work with the guideline has shown that a systematic approach is needed to obtain an overview of the research that has already been done, and well-designed primary studies are needed in order to provide additional evidence.

The guideline is a sequel to the report The use of dental filling materials in Norway, that was presented to the Minister of Health in 1998. Work on the guideline began in 1999 at the Norwegian Board of Health. The process has been lengthy and has probably already contributed to changes in practice.

National clinical guidelines issued by the Directorate for Health and Social Affairs describe what are considered to be good practice at the time of publication. In principle, guidelines are to be considered as recommendations and advice, and shall be based on sound, up-to-date professional knowledge. Guidelines are intended to be an aid for health care personnel when making decisions, to enable them to achieve acceptable standards and high quality service performance.

National clinical guidelines are not directly legally binding for the recipients, but they can, to a large extent, direct the choices that have to be taken. By following the current national clinical guideline, professionals will contribute to fulfilling the demands in the legislation of sound professional standards. If one chooses solutions that deviate to a substantial degree from the national clinical guideline, one ought to document this and be prepared to justify ones choice.

This guideline was prepared by a working group at the Directorate for Health and Social Affairs. Representatives from dental health professionals and the Norwegian Dental Patient Association have made valuable contributions during hearings and consultative meetings. I would like to thank everyone who has contributed to this work for their efforts and commitment, and I hope that the guideline will be of help for dental health care service.

The guideline came into force on 1 July 2003.

Oslo, 17 March 2003

Bjørn-Inge LarsenDirector,

Directorate for Health and Social Affairs, Norway

5

2 F O R E W O R D

66

Recommendations

Preventive treatment should be given priority.

Dental tissue-conserving techniques shall always be chosen when dental filling therapy is necessary.

Amalgam should not normally be the first choice for any indication of dental filling therapy.

Use of amalgam should be limited as much as possible in consideration to the environment and possible adverse health effects.

Dental filling therapy should be avoided during pregnancy.

Contact between amalgam and other metals must be avoided when placing new dental fillings.

Allergy to a component of a dental filling material is a contra-indication for use of the material.

Every effort should be made to reduce the exposure of patients and dental health care personnel to chemical substances during dental treatment, both when placing and removing dental fillings.

Water cooling and suction shall be used when removing old dental fillings.

Contact with materials before they are hardened should be avoided.

Conditions and Principles:

Choice of dental filling material should be based on the patient’s case history, clinical, radiographic and other relevant findings and an assessment of the patient’s ability to follow advice and recommendations on how to take care of his or her own dental health.

The dentist is responsible for the choice of dental filling material (Health Care Personnel Act, section 4). The decision should be made with the consent of the patient or guardian. If the choice of dental filling material deviates from the guideline for material choice, the reason for this should be given and the patient’s informed consent registered in the patient record.

The indications, contra-indications and use of the material as specified by the manufacturer must be followed. The use of pre-portioned packages ensures proper composition of the dental filling material and optimal quality. In addition their use reduces the chances of dental health care personnel coming in contact with unhardened materials.

3 S U M M A R Y

3.1

3.2

•

•

•

7

4 I N T R O D U C T I O N

4.1

•

•

•

•

4.2

The purpose in publishing this guideline is to create a common basis for practitioners’ choices of dental filling material. There is an ambition that the work shall be followed up and that future editions of the guideline will be based on a more extensive evidence base. During the formulation of the guideline, it became evident that there was an inadequate amount of summarized evidence in several fields. Therefore, the Directorate for Health and Social Affairs recognises a need for a systematic compilation of the already available research and the need to initiate new research in areas where there is a lack of evidence. This is discussed more fully in Chapter 11.

Knowledge about dental filling materials is especially important for dental health care personnel and is also presumably of interest to a large section of the public because the majority have dental fillings. Completion of the guideline represents a long process that has taken many years of work, which is outlined in Chapter 10. It must be mentioned here that the working group faced a dilemma. In some areas review articles were found that did not meet the criteria of the Directorate for Health and Social Affairs. However, it was decided to include these articles, because review articles are believed to be more informative than primary studies.

The Directorate for Health and Social Affairs believes that facts about what can be expected of various materials in terms of their life expectancy as dental fillings and their side-effects are especially important.

The Directorate for Health and Social Affairs has based its recommendations on the best available evidence. Extensive searches in databases have been conducted to obtain research results.

The principle of prevention and the principle of substitution are among the other important considerations which have shaped the guideline. These principles are general and apply to choices of all dental filling materials. Moreover, due attention has been given to the opinions of patients and dental health care personnel.

The guideline has been developed on the basis of Norwegian health care legislation.

The Goals

Dental health care personnel have the knowledge to make decisions concerning the use of dental filling materials.

The population receives a safe, high quality dental health care service.

The population’s exposure to mercury is reduced.

Mercury discharge into the environment is reduced.

The Target Group

Health professionals in the dental health care service.

88

The guideline builds on evaluations based on scientific articles and experience, the principles outlined in Chapter 6, and Norwegian health care legislation.

Extension for Prevention, or Prevention with Minimal Extension

In principle, dental fillings are prostheses that replace a natural highly specialized tissue. It is extremely difficult to find materials suited for this task, and at present, the ideal dental filling material does not exist. Preventive and interceptive treatment must be given priority, whenever it is sound practice. When a dental filling must be placed, it is important to choose a tissue-conserving technique, that is a technique that involves minimal removal of dental tissue (1).

Glass ionomer cements and composites bind themselves to dental tissue. These require less removal of tooth tissue than amalgam to gain retention. Moreover, they are more satisfactory than amalgam cosmetically, and do not seem to cause environmental pollution. There seems to be little difference between the various dental filling materials in their ability to hinder the formation of secondary caries (2).

In the assessment leading to the following recommendation, it is emphasized that in a lifetime perspective it is favourable to preserve as much dental tissues as possible. This will save teeth in the long run, and presumably save expense on complicated restorations later in life.

Preventive treatment should be given priority.

Dental tissue-conserving techniques shall always be chosen when dental filling therapy is necessary. Black’s principle “extension for prevention” is now inappropriate. “Prevention with minimal extension” is the prevailing principle.2

5 E V A L U A T I O N S A N D R E C O M M E N D A T I O N S

5.1

2G.V. Black (1836–1915) Dentist (USA) developed the principles for cavity preparation. These included the

necessity to remove enough dental tissue to insure good retention for the fi lling, as well as the necessity to extend the cavity into a so-called “self-cleansing area”, in other words, tooth surfaces that are easy to keep clean. His principles involved the removal of much healthy tooth tissue.

Level 1

Level 1

Assessment

9

Durability of Dental Filling Materials

Table 1: Failure rate for dental filling materials in permanent teeth according to two reviews

Dental filling material Failure rate after 5 years for dental fillings in all tooth surfaces, in %

Annual failure rate for dental fillings in mastication surfaces, in %

Amalgam 4.5 0–7

Composite 21.8 0–9

Glass ionomer cement and similar materials

35.1 1.4–14.4

Composite inlay 0–11.8

Ceramic inlay(fired/cast) 14.7 0–7.5

Ceramic inlay(CAD/CAM) 0–4.4

Gold inlay 0–5.9

Appropriate tooth-coloured dental filling materials have long been generally accepted as the first choice for deciduous teeth, even though they do not tolerate the same masticatory force as amalgam. For badly-decayed deciduous teeth, steel crowns are a good alternative (5). Glass ionomer cements and composites are a natural first choice in the treatment of primary caries in permanent teeth. There is also a clear trend to replace amalgam with other dental filling materials in general dental practice for adults (6–10).

When replacement of an amalgam filling is indicated, a cavity has already been prepared and the argument that the new dental filling materials conserve tooth tissue is no longer relevant. In some cases when a large amalgam filling needs to be replaced, the choice may be between another amalgam filling or a crown.

When treatment has to be done under general anaesthesia, in principle the same guidelines apply as for other dental treatment. However, in such cases, the time factor is critical due to the volume of work that must be completed in a limited amount of time to reduce the risk involved with general anaesthesia. Therefore, it must be accepted that the dentist in such circumstances chooses time-saving techniques.

In the assessment leading to the following recommendations, it is emphasized that the durability of the new materials is approaching that of amalgam.

Amalgam should not normally be the first choice for any indication of dental filling therapy.

V

5.2

Level 3

Level 4

Level 4

Assessment

1010

Release of Mercury from Amalgam Fillings

In the search for evidence no good systematic surveys were found on this topic (see Chapter 11).

The evidence presented here has been collected from primary studies recommended by Norwegian experts, and from the references in the report IK-2652.

Some risk of side effects is associated with all materials used as dental filling materials. However, the prevalence of side effects is low. During recent years, the relative proportion of reported cases of amalgam-related side effects has been stable. No significant increase in the number of cases of side effects associated with other dental filling materials has been noted, even though their use has increased. According to the Dental Biomaterials: Adverse Reaction Unit annual reports of 1998, 1999, and 2000, sub-cutaneous tests for allergy indicated that amalgam and plastic components in dental filling materials were the substances that elicited the lowest number of positive reactions. Most positive reactions were elicited by gold, palladium and nickel. The clinical relevance of positive reactions from sub-cutaneous tests must be assessed for each individual case (11). Based on the side effect profile of different materials, it is difficult to give general recommendations for the choice of one dental filling material over another.

Amalgam has been used in the Norwegian dental health care services for more than a hundred years. It is the dental filling material that has contributed most to the eradication of edentulousness in Norway, because it was inexpensive and easy to use. However, there is vast agreement that mercury in amalgam fillings represents a considerable portion of mercury exposure to the general population (12–13). It is well known that high doses of mercury result in adverse health effects that lead to disturbances in brain function, kidney function, the immune system and foetal development. 12). There is no data basis to determine a minimum mercury level that is safe (14). However, mild sub-clinical effects have been observed with doses corresponding to those that some people can have from amalgam fillings (15–16). Epidemiological studies have failed to establish any connection between amalgam fillings and illness (17–19), however, the existence of health effects can not be excluded (20).

The amount of mercury vapour released from amalgam fillings increases with chewing, brushing and bruxism (tooth grinding). There are reports of individuals that have had a high content of mercury in blood or urine because of intense gum chewing in an attempt to stop smoking. Considerably lower mercury levels in some of the same individuals have been shown after the replacement of dental fillings (21–25).

During the last 10 to 15 years, it has been documented that mercury from amalgam fillings can be traced in undesirable places in the human body. It has been shown that there is a correlation between the concentration of mercury in the brain and the number of amalgam fillings in the deceased person (26). Mercury crosses the placenta, and there is a correlation between the concentration of mercury in the foetus and the number of amalgam fillings in the mother (27). The amount of mercury in breast milk increases with the number of amalgam fillings in the mother (28). Individuals with amalgam fillings have higher levels of mercury in body fluids than those without amalgam fillings (12–29).

It has been reported that the majority of people who maintain that their ill health is caused by amalgam fillings experience an improvement in health after the fillings have been replaced. However, the complex picture of cause and effect remains to be elucidated (30). No connection between the level of mercury in body fluids and symptoms has been established (29).

5.3

Level 3

Level 2

Level 3

Level 3

Level 3

11

There are several other uncertain factors, for instance the possibility for methylation in the human body makes determination of mercury exposure from amalgam fillings more uncertain (12, 31, 32).

The available evidence is inadequate to establish that exposure to mercury in amalgam fillings leads to health effects other than allergic reactions. However, risk analysis indicates that there is some possibility for adverse health effects caused by mercury from amalgam fillings in a small minority of the population (33).

The margin between the amount of mercury that some individuals with amalgam fillings have and the amount that can affect health is narrow. The Norwegian Institute of Public Health points out that “even though an overall assessment indicates that there is little possibility that lead, mercury and cadmium present a significant health risk in the Norwegian population, it must be said that the safety margins for all these metals are relatively narrow in relation to their potential for triggering subtle health effects” (34).

Mercury from dental fillings is the only component of dental filling materials that is reckoned to be an actual environmental problem. In particular, the great increase in concentration that occurs in the food chain is problematic. Both in consideration to the environment and public health, the use of heavy metals should be kept as low as possible. Even though all dental clinics in the country are now required to collect all amalgam debris in special containers, the National Pollution Control Authority still maintains that it is desirable to find more environmentally safe dental filling materials than amalgam. In the plan of action issued by the Norwegian Ministry of the Environment, it is recommended that strong measures should be taken in the work for reducing pollution or phasing out the use of environmental pollutants. Mercury is among the most problematic of such pollutants (35–36).

In the assessment leading to the following recommendation, the main emphasis has been placed on the following: Even though it has not been proved that amalgam fillings cause adverse health effects in groups of the population that have such dental fillings, concern about the release of mercury from amalgam fillings has increased as new evidence has become available.

Use of amalgam should be limited as much as possible in consideration to the environment and possible adverse health effects.

Level 3

Level 3

Level 3

Level 3

Assessment

1212

Substitutes for Amalgam

It has been documented that dental filling materials containing plastic resins may release unreacted resin components initially after polymerization. Degradation of the polymers may also lead to the release of resin components (37). Apart from allergic reactions, little reliable information is available about other possible damage to health caused by these substances. Attention has been especially directed towards bisphenol A and / or bisphenol A derivatives. These substances are hormone mimics, and it has been shown that they have an effect on cell cultures similar to that of oestrogen. However, the amount that is produced of such substances is small. At present there is little evidence about whether exposure to low doses of hormone mimics has adverse effects on health (38). This should be clarified, particularly in relation to the possible additive effects of substances in the environment with similar effects.

Two articles are referred to above that are excluded in Chapter 11, as they do not meet the criteria for good systematic reviews by the Directorate for Health and Social Affairs. However, they are referred to and are included in the references because review articles are considered to contain more knowledge than articles on primary studies. Both articles conclude that more evidence is required.

In the assessment leading to the recommendation given below, emphasis has been placed on the following: In the guideline IK 51/91, the health authorities recommend the avoidance of extensive use of amalgam during pregnancy. Owing to the lack of information concerning new materials, the Directorate for Health and Social Affairs deems it appropriate to extend that recommendation to cover all dental filling therapy.

Dental filling therapy should be avoided during pregnancy.

Recommendations for Practice

In line with the earlier guideline IK 51/91 and advice from the Dental Biomaterials: Adverse Reaction Unit, the Directorate for Health and Social Affairs recommends the following:

Contact between amalgam and other metals must be avoided when placing new dental fillings.

Allergy to a component of a dental filling material is a contra-indication for use of the material.

Every effort should be made to reduce the exposure of patients and dental health care personnel to chemical substances during dental treatment, both when placing and removing dental fillings.

Water cooling and suction shall be used when removing old dental fillings.

The Working Environment

Contact with unreacted plastic materials appears to involve the greatest risk for development of allergy for dental health care personnel (39). As a publication on the themes health, environment and safety in the dental health care services is planned, this subject will not be elaborated on in this guideline.

Contact with materials before they are hardened should be avoided.

5.4

5.6

5.5

Level 3

Assessment

Level 3

13

Overlying Principles

The public health perspective and the Precautionary PrincipleAmalgam is one of the oldest dental filling materials available, and has been periodically controversial throughout its history of use. It has long been known that mercury is released from amalgam fillings. A lot of new evidence has become available during the last decade that shows that amalgam releases more mercury, and that more mercury from amalgam is absorbed into the human body, than was previously believed.

Mercury is one of the most problematic environmental pollutants. It has been documented that mercury from amalgam fillings significantly contributes to the population’s total exposure to mercury (12). The documentation that has been presented until now does not show that mercury released from amalgam fillings is the cause of health problems in patients with no clearly-defined set of symptoms, even though some patients who maintain that their health problems are due to amalgam fillings experience an improvement in their health after the removal of amalgam dental fillings. However, in line with the precautionary principle, it is important that the population’s exposure to mercury be held at the lowest possible level (35, 36, 40). It is therefore natural to discontinue the use of amalgam and to use other dental filling materials as much as possible, since good alternatives are available.

New dental filling materials may also have undesirable effects, which have not yet been fully investigated, or which have not yet been detected. There is a certain amount of documentation concerning undesirable effects of tooth-coloured materials (37, 38). Thus, there is reason to be cautious when new materials are introduced. Dental filling materials, including fissure-sealants, should only be used when clearly indicated.

In practice, this involves a greater emphasis on preventive measures, a “wait-and-see” approach to the use of dental fillings, and the use of cavity preparation techniques that involve minimal removal of tooth tissue when a dental filling must be placed. In line with the precautionary principle, dental filling therapy should also be restricted during pregnancy.

The Principle of SubstitutionAccording to the principle of substitution, an assessment shall be made about whether chemical substances that can lead to adverse health effects or environmental damage can be substituted with less damaging substances.

The Norwegian Product Control Act, section 3a stipulates substitution as a legal duty. More specifically, it requires any company or establishment that uses a product containing a chemical substance that can lead to adverse health effects or environmental damage, shall choose an alternative substance that causes less risk of such effects, provided that this does not involve unreasonable expenditure or disadvantages. The Norwegian health administration is required by law (Ot.prp. nr. 40 1998–99 through Innst.O.nr.70 1998–99) to observe the principle of substitution. In the opinion of the Directorate for Health and Social Affairs, section 3a of the Norwegian Product Control Act applies to amalgam, because of its high mercury content. Alternatives to amalgam seem to represent a considerably lower environmental problem, and therefore a lower risk to public health, than amalgam.

Several good alternatives to amalgam are currently available to dentists. None of them can replace amalgam for all its indications, but together they cover all the indications.

6 O V E R LY I N G P R I N C I P L E S A N D R E G U L A T I O N S

6.1

6.1.1

6.1.2

1414

It is well known that resin-based materials can constitute a risk to the working environment. This is related to skin contact with unreacted resins. The risk can be eliminated by practising non-touch techniques. Here the dentist has a duty to inform his or her assistants of the dangers involved, and to ensure that the assistants learn to handle the materials safely (Health Care Personnel Act, section 5). Reference is also made to the Regulations of 6 December1996 relating to systematic health, environment and safety activities in the workplace, and the Regulations of 10 December 2002 relating to internal control in the health and social services.

Some Key Regulations in Health Legislation

Responsibility and Sound Professional StandardsThe dentist is responsible for the dental treatment of the patient, including the choice of dental filling material. As a health care personnel the dentist has a duty to execute his or her work in accordance with the requirements of sound professional standards, and caring help that can be expected according to his/her qualifications, the nature of the work and the general situation (Health Care Personnel Act, section 4). Furthermore, sound professional standards implies that the patient has the right to be involved, among other things, with the choice between available and sound methods of treatment. (Patients’ Rights Act, section 3–1). The dentist has a duty to provide information according to the Health Care Personnel Act, section 10, and the Patients’ Rights Act, sections 3–2 to 3–4.

Treatment in accordance with sound professional standards means that every case must be assessed individually. The choice of dental filling material must be based on case history, clinical, radiographic and other relevant findings, as well as a detailed diagnosis based on this information. The patient’s preferences and an assessment of the prognosis must also be taken into account. Choice of treatment must also take into consideration the ability of the patient to follow advice and instructions from dental health care personnel. The competence, skill and experience of dental health care personnel in handling various materials can be of great importance for a successful result.

The indications, contra-indications and handling methods specified by the manufacturer must be followed. The use of pre-portioned packages ensures proper composition and optimal quality of the dental filling material. In addition their use reduces the chances of dental health care personnel coming in contact with unhardened materials. A note shall always be made in the patient’s records of exactly which products have been used.

In order to avoid unnecessary exposure of health care personnel and patients to potentially toxic substances, water cooling and suction shall be used when removing old dental fillings. Further guidance on the removal of amalgam fillings can be found on the website for the Dental Biomaterials: Adverse Reaction Unit: www.uib.no/bivirkningsgruppen.

Participation, Information and Informed ConsentThe patient’s or the guardian’s right of participation and access to relevant information has been established by the Patients’ Rights Act. The patient’s right to participate in the choice of treatment when several types of treatment are considered to be professionally sound is specifically mentioned. In practice, this involves consulting the patient or guardian about the choice of dental filling material. The dentist has the right, and according to the circumstances, a duty to refuse to perform treatment that he or she does not regard as professionally sound (Patients’ Rights Act, section 4).

6.2

6.2.2

6.2.1

1515

Prior to and during treatment the patient shall be given the information that is necessary for him or her to understand his or her health status, what the health care involves and the possible risks or side effects. This also means that the patient/guardian must be informed about recommendations from the national health authorities. The information must be adapted to the patient’s individual comprehension level, taking into account his or her age, experience, and cultural and linguistic background. As required by Chapter 3 of the Patients’ Rights Act and section 8j of the Regulations relating to patients’ records, the content of the information given to the patient shall be entered in the patient’s record, to the extent that it is relevant and necessary. If the dentist and the patient agree on a method of treatment or a material that is not recommended by the national health authorities, the reasons for such a choice and the patient’s informed consent should be on record as required by section 8i, Regulations relating to patients’ records. When information has been given and the conditions for informed consent have been met, attending for treatment may be interpreted as tacit consent (Patients’ Rights Act, section 4–2).

The Costs

The calculation of costs associated with various dental filling materials over time is associated with uncertainty. These calculations are prognoses, and prognoses are uncertain when the basis for them is divergent and partly incomplete. Most studies in this field are of poor quality (10). However, there are some main features that recur.

Glass ionomer cements and composite materials are more expensive than amalgam. Dental fees for tooth-coloured dental filling materials are also generally higher than those for amalgam fillings (10).

During the hearings on the guideline, several county dental officers pointed out that practice in the dental health care services is already in line with the recommendations, and that the immediate economic consequences to the public dental service would be insignificant. The National Insurance Administration has a similar argument and believes that implementation of the guideline will not have economical consequences for social security.

It is possible that in a ten-year perspective alternatives to amalgam will lead to higher maintenance costs. (41). In Norway it is mainly the patient that must bear the additional costs. However, in the long run, and in a lifetime perspective, it may be less expensive for some patients. Tissue-conserving techniques and adhesive filling materials may lower the risk of dentine fracture, and thus save the patient for complex and costly dental restorations (42).

6.3

16

Both from an environmental and public health perspective, it is desirable to reduce exposure to mercury. The Directorate for Health and Social Affairs recommends that the use of amalgam as a dental filling material should be reduced as much as possible.

The guideline does not prohibit the use of amalgam, but dentists are encouraged to reduce its use.

The guideline does not recommend the removal of amalgam fillings for symptom-free individuals.

Special and substantial reasons must exist for the use of amalgam in children and adolescents.

When the replacement of a dental filling in an adult is indicated, a filling material other than amalgam ought to be used. If a patient wishes to have amalgam as the dental filling material, this ought to be accepted.

The Directorate for Health and Social Affairs is of the opinion that it is important to reduce the use of all dental filling materials. This requires greater efforts on preventive measures, and they will be given due priority.

The Directorate for Health and Social Affairs has not given comprehensive advice about specific choices of dental filling material. The reason for this is that the evidence base is inadequate. One explanation for this lack of evidence is the frequent introduction of new materials and new classes of material. However, the Directorate provides some important guidance about what should be considered in the choice of material.

The Directorate for Health and Social Affairs is also of the opinion that a quality-controlled database on the use of dental filling materials / odontological biomaterials should be established. The database should be regularly updated, so that the advice given about the materials that dentists ought to use has an increasingly better foundation.

With this guideline, the Directorate for Health and Social Affairs contributes to the Ministry of the Environment’s Norway’s Action Plan for Hazardous Substances, T-1311, 1999.

7 C O N C L U S I O N S

1.

2.

3.

4.

5.

6.

7.

8.

9.

17

Sweden

Several reports on the use of amalgam in the dental health care service have been published in Sweden. The latest report was published in 1998 (43). The Swedish Government has intended to prohibit amalgam. The government announced in the budget proposal for 1999 (Prop. 1998/99:1) its intention to take necessary action to introduce a ban on the use of amalgam in Sweden by 2001. However, it has become apparent that EU regulations and signed agreements probably make it impossible to introduce a ban on the use of amalgam. In the budget proposal for 2001 (Prop. 2000/01:1), the Swedish Government announced that it will explore the possibility of banning amalgam out of consideration to the environment.

Many county councils have adopted amalgam-free dental care for children and adolescents.

Swedish health care insurance includes dental treatment. No reimbursements are made for amalgam fillings, while composite fillings qualify for reimbursement. It is assumed that this has contributed to the phasing out of amalgam.

Finland

As early as 1993, the National Research and Development Centre for Welfare and Health (STAKES) in Finland issued recommendations to reduce the use of amalgam in the dental health care service:

Use of amalgam as a dental filling material should be reduced for environmental reasons.

Amalgam should only be used as a dental filling material when other dental filling materials cannot be used.

Since there is no conclusive evidence that amalgam is injurious to health, there are no grounds for routine removal of sound amalgam fillings.

Denmark

The sale of mercury has been forbidden in Denmark since 1994, but an exemption has been made, until further notice, for mercury in amalgam.

8 T H E S I T U A T I O N I N T H E O T H E R N O R D I C C O U N T R I E S

8.1

8.2

8.3

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•

•

18

The present guideline came into force on 1 July 2003 and is available on our website www.shdir.no.

The Directorate for Health and Social Affairs will provide information to county dental officers, and is available to take part in meetings arranged by local organizations and by the public dental service.

The Directorate for Health and Social Affairs will ensure that:

The guideline will be printed and distributed to all dental health care personnel in the dental health care services.

The last three issues of Bivirkningsbladet, the journal of the Dental Biomaterials: Adverse Reaction Unit in Bergen, will be reprinted and distributed to all dental health care personnel in the dental health care services.

NIOM-info, bulletin of the Scandinavian Institute of Dental Materials, will also be reprinted and distributed.

The Norwegian Association for the Promotion of Oral Health is preparing a booklet for patients, which will be for sale. All dental health care personnel in the dental health care services will receive up to five copies of this publication with the guideline.

A survey was carried out in November 2002 to ascertain the extent to which amalgam and other dental filling materials are used in Norway. The results will be reported and the survey will be repeated in about five years.

9 I M P L E M E N T A T I O N , E V A L U A T I O N A N D U P D A T I N G

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Work on the guideline commenced in 1999 at the Norwegian Board of Health. It was commissioned by the then Norwegian Ministry of Health and Social Affairs through the national budget as a follow-up of the report The use of dental filling materials in Norway IK-2652 – Norwegian Board of Health report series, that was presented to the Minister of Health in October 1998. The report is available on the website for the Norwegian Board of Health: www.helsetilsynet.no. The first chapter is available in English, IK-2675, 1999.

The Work Process

In the autumn of 1999, the Norwegian Board of Health appointed a central working group (Appendix 1). It was decided that the follow-up of the report The use of dental filling materials in Norway should include:

1. A two-day conference including an international and a national day. The conference was held in May 2000. The themes for the international conference were:

Adverse effects of oral biomaterials

International reporting systems and future research

The proceedings from this conference are available on the website for the Directorate for Health and Social Affairs: www.shdir.no.

2. Compilation of new guidelines within three areas:

The national day was used to discuss drafts for three guidelines.

a. Guideline for the use of dental filling materials (this guideline). The first draft was compiled by representatives for NIOM (the Scandinavian Institute of Dental Materials) and the Faculties of Dentistry in Oslo and Bergen.

b. Guideline manual for survey of patients with symptoms presumed to be related to dental filling materials. The target group is dentists and doctors. The first draft was compiled by the Dental Biomaterials: Adverse Reaction Unit at the University of Bergen. A revised draft is available on their website: www.uib.no/bivirkningsgruppen

c. Health, the working environment and safety in the dental health care service. The target group is employers and employees in the dental health care services (has priority after a and b). The first draft was compiled by the then Trondheim General Hospital, Department of Industrial Medicine.

The first drafts of the three guidelines were thoroughly discussed and revised by the central working group. Afterwards, the three drafts were discussed in separate specially designated reference groups at the national day in the two-day conference on dental filling materials held in May 2000.

The members of the reference group who revised the Guideline for Dental Filling Materials at the national conference day in May 2000 are listed in Appendix 2.

In the autumn of 2000 a revised draft was sent out for comments internally to the groups who had been involved in preparing and revising the draft. The work in the groups was naturally characterized by the considerable differences of opinion on the issue of the use of amalgam. The differences of opinion became even more evident when the internal hearing was completed, and an attempt was made to incorporate the comments from the hearing into the drafts. Representative from NIOM withdrew from further work in the autumn of 2000.

1 0 D E V E L O P M E N T O F T H E G U I D E L I N E

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At this point, the Norwegian Board of Health determined that the health authorities should prepare a discussion document, that would take into account the facts that were presented in the report IK-2652, the work process with the guideline, and the expert opinions from the internal hearing during the autumn of 2000. This work was done at the Norwegian Board of Health in 2001.

The discussion document was considerably delayed because of reorganisation of the central health administration. The reason for this was that the newly created Directorate for Health and Social Affairs, that has responsibility for preparing guidelines , wished to introduce more stringent requirements for process and documentation in the production of guidelines. When the draft guideline was sent out for comments in the summer of 2002, work continued in the Directorate for Health and Social Affairs. Relevant questions were formulated and systematic searches for review articles and national clinical guidelines were carried out. The review articles were evaluated for their relevance and methodical quality, and those that met the standards of the Directorate for Health and Social Affairs were summarized.

Some review articles are referred to in Chapter 11, even though they did not meet the Directorate’s quality criteria. Some of these articles are referred to in the text, because it is accepted that a review article can provide more information than primary studies. These articles are included in the references, even though the working group in the Directorate for Health and Social Affairs was sceptical.

Within the time limits, there was not enough time to carry out a search and evaluate primary studies on issues not included in review articles. Experts were contacted to identify good primary studies, and these were procured in areas where reviews were lacking. Because no systematic search for primary studies was carried out, the working group cannot be certain that all documentation within these areas has been found. Good primary studies may have been overlooked.

Two consultative meetings have been held with interested parties after reorganisation of the central health administration. The lists of participants are given in Appendices 4 and 5.

21

Methods for selection and critical appraisal of the available scientific information

The following questions were formulated:1. What is the durability of amalgam, glass ionomers, and composite and ceramic filling materials?

2. Which substances are released by the various types of dental filling materials?

3. Are there adverse effects on health of diverse dental filling materials?

4. What are the effects of various dental filling materials on the working environment for the dental health professionals?

5. What are the costs of treatment using different dental filling materials?

The sources searchedThe following databases and websites were searched (autumn 2002) for systematic reviews and guidelines:

American Academy of Periodontology

Australian Dental Association

Australian Safety and Efficacy Register of New Interventional Procedures - Surgical Bandolier

British Dental Association

The British Dental Journal Supplements - Evidence-based dentistry- Evidence-based medicine- Health Evidence Bulletins Wales - The Journal of Evidence-based Dental Practice- The Canadian Collaboration on Clinical Practice Guidelines in Dentistry

The Canadian Task Force on Preventive Health Care

Centre for Reviews and dissemination, CRD database.

CEHTA, Centre for Evaluation and Health Technology Assessment (formerly DIHTA)

Centre for Evidence-based Dentistry

Centre for Health Services & Policy Research, College of Health Disciplines & The University of British Columbia

Cochrane Library Danish Centre for Evaluation and Health Technology Assessment

Developmental and Reproductive Toxicology and Environmental Teratology Information Center

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Department of Public Health and Epidemiology University of Birmingham

DSI, Institutt for sundhedsvæsen EBM Reviews - ACP Journal Club via OVID

EBOC, Evidence based oncall Hot cats FinOHTA, Finnish office for health care technology assessment

IADR/AADR, International association for dental research

INAHTA, International network of agencies for health technology.

IRIS, Integrated Risk Information System National Guidelines Clearinghouse

NeLH, National electronic Library for Health, Pilot search engine

NICE, National Institute for Clinical Excellence

The Research Findings Electronic Register SBU, Statens Beredning för Medicinsk utvädering

ScHARR, School of Health and related research, University of Sheffield

SEEK, Sheffield Evidence for Effectiveness and Knowledge

SMM, Senter for medisinsk metodevurdering

Sum Search TOXNET

TRIP, Turning Research Into Practice The Wessex Institute for Health Research and Development

West Midlands Health Technology Assessment Collaboration

WHO, Oral health

Electronic journals:ACP journal club

Other sources:The material in the list of references of the report IK-2652, The Use of Dental Restorative Materials in Norway was searched and to some extent we consulted several experts.

23

Inclusion and exclusion criteriaInclusion: Systematic reviews and review articles that met certain minimal requirements to methodology quality such as use of clear selection criteria, clear search strategy and a description of how the studies reviewed were found and the methods of assessment and critical appraisal used.

A systematic review is a review where the authors have used a systematic and an explicit method to find, assess, and sum up primal studies considering the same questions. A review of poor quality can give an unbalanced and distorted view of the available research.

Exclusion: Articles on cost issues, primal studies, and textbooks have been excluded here.

No systematic search for material that could enable us to deal with the fifth issue was made, because at present, the Department for Knowledge Support does not have the competence to make assessments in this area.

The selection of reviews was independently carried out by two persons (LMR and LSA). Their initial choice was mainly guided by titles and summaries given in the review articles.

Two persons (LMR and AS) carried out a comprehensive quality assessment of the full-text versions of the initial selection. It was done with the aid of a checklist for critical appraisal provided by the Department of Knowledge Support. Reviews that did not meet certain criteria were excluded.

Summary of the findings

Only one quality guideline (Preventing Dental Caries in Children at High Caries Risk, SIGN Publication No. 47 December 2000) was found, but it was not relevant in dealing with the issues taken up here. This guideline is concerned with prevention of caries in children. An SBU report of high quality (Att förebygga karies, SBU-rapport nr 161, 2002), was also found, but as it also deals with prevention, and it is not included here.

Findings from the reviews dealing with the areas concerned

Question 1: What is the durability of amalgam, glass ionomers, and composite and ceramic filling materials?Our search yielded six review articles, of which the work by Chadwick et al 2001, and Hickel 2001) were thought to merit inclusion. The others (Baghdadi, ZD Preservation-based approaches to restore posterior teeth with amalgam, resin or a combination of materials Am J Dent 2002;15:54–65, Downer MC, How long do routine dental restorations last? A systematic review. British Dental Journal 1999; 187(8): 432–9, Hickel R et al. Clinical results and new developments of direct posterior restorations. Am J Dent. 2000 Nov; 13 (Spec No):41D–54D, and Roulet JF, Benefits and disadvantages of tooth-coloured alternatives to amalgam. Journal of Dentistry 1997, Vol 26;6.459–473), were excluded on methodological grounds, or because newer articles provided more up-to-date information.

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The included reviews.Chadwick B. L, et.al.NHS Centre for Reviews and Dissemination: What type of filling? York 1999, The Longevity of Dental Restorations A systematic review, Report 19, 2001.

This systematic review deal with the questions of durability and the cost of various dental fillings in permanent teeth. It reviews 195 studies on durability, and 30 on cost analyses.It is a sufficiently comprehensive review, it includes randomized, and controlled studies, quasi-experimental studies, and non-experimental studies where one has studied the durability of dental fillings in a cohort that has been well followed-up. Some of the experimental or clinical studies include only a small number of patients and in general an adult population.

Moreover, the review includes studies from a variety of countries, Australia, Belgium, Brazil, Canada, Cambodia, Denmark, Germany, Great Britain, Egypt, Finland, Italy, Israel, Japan, New Zealand, Norway, Poland, Sweden, Switzerland, Singapore, The Netherlands, Turkey, U.S.A, and Zimbabwe.

Studies on the following filling materials have been reviewed:

Mercury amalgam

Composites with and without dentin bonding

Comparisons between amalgam and composites

Glass ionomers

Glass ionomers and composites modified with polymers

Gold and other alloys

Porcelain.

ResultsWhen new filling materials are introduced, one often has no adequate knowledge of their long-term effects. No dental filling material is permanent and about 60% of dental restorations are concerned with replacing old fillings.

According to the review, unless motivated by cosmetic reasons, amalgam remains the commonest filling. It is the longest lasting and the cheapest available filling material. The new composites are more durable than the older types.

Composites and glass ionomers as applied by the sandwich technique in treating class 2 fillings are not durable, and hence cannot be recommended.

A Dentist’s subjective decisions concerning a course of treatment can result in less than optimal results. Basing such decisions on sound scientific criteria would enhance the quality of treatment.

Assessment of the methodology in useThe search strategy was given (medline and Embase). The selection of the material has been guided by a set of objective criteria, which is given in the review. Studies were excluded if they did not have objective outcome measures. Conclusions from the review are based on studies which deal with the durability of various dental filling materials under near laboratory conditions.

11.3.1

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The reviewers also draw attention to the lack of systematic classification and wrongly classification of the relevant references and studies in the databases. Many studies were found by hand searching of journals. Classification and systematic indexing of various studies in dental restoration still remains a problem and can present a challenge for future systematic reviews.

Hickel,R; Manhart, J.Longevity of Restorations in Posterior Teeth and Reasons for Failure. J Adhesive Dent 2001;3:45–64

This review takes up the problems of durability of dental fillings in the molar surfaces subject to masticative pressure, and the reasons for their failure.

It includes cross-sectional studies, prospective observational studies and controlled studies. It covers studies on amalgam, composites, glass ionomers, and Gold inlays. The review assesses studies concerned with durability of various filling materials, fractures, and secondary caries.

Summary of the results AmalgamNumber of studies reviewed: 34.Period covered by the studies:1969–1999.Follow-up period: 5–20 years.Annual failure rate: 0–7%.Causes of failure: Secondary caries, fracture of the filling or tooth, and marginal ditching.

CompositesNumber of studies reviewed: 24.Period covered by the studies: 1988–2000.Follow-up period: 2–over 25 years, mostly from 5–10 years.Annual failure rate: 0–9%.Causes of failure: According to the studies undertaken between 1970 and 1980, wear fractured fillings, and inadequate adhesion are the major reasons for their replacement. Hybrids are better than micro-fillers. Bonding materials used earlier resulted in a high incidence of secondary caries.

Glass ionomersNumber of studies reviewed: 16.Period covered by the studies: 1988–1999.Follow-up period: 1–25 years, mostly 3–5 years.Annual failure rate: 1.4%–14.4%.Causes of failure: Fractured fillings owing to brittleness, and secondary caries.Remarks: Use requires high technical skill.

Composite inlays and onlaysNumber of studies reviewed: 13.Period covered by the studies: 1991–2001.Follow-up period: 1–7 years.Annual failure rate: 0–11.8%.Remarks: When expertly done, composite inlays seem to be better and more durable than the composite fillings.

Ceramic inlays and onlaysNumber of studies reviewed: 24.Period covered by the studies: 1988–2001.Follow-up period: 1–10 years.Annual failure rate: 0–7%, for cad/cam 0–4.4%.Causes of failure: Mainly the fracturing of the ceramic.Remarks: Use requires high technical skill.

26

Gold inlaysNumber of studies reviewed: 12.Period covered by the studies: 1991–2000.Follow-up period: 1–12 years.Annual failure rate: 0–5.9%.Causes of failure: Damage to teeth and secondary caries.Remarks: Little information is available on the durability of gold inlays. Its high cost excludes it from general use.

General remarksThe durability of dental restorative materials is not solely dependent on their physio-chemical properties. The patient’s age, oral hygiene, and life-style including the eating habits also play a significant part in determining how long a dental restoration may last.

Assessment of the methodology in use.Source of the material under review has not been given. While the reviewer subjects the studies to a critical appraisal, no explicit selection criteria are provided. It is pointed out that the controlled studies fail to reflect how and under what conditions Dentistry is practised.Findings are based on observations of varying quality. Thus, it is difficult to ascertain with certainty, the other significant factors that may influence the durability of dental restorative materials.

Comparison of glass ionomers with other filling materialsThe following adequate systematic review compares the possible secondary caries inhibition effect of glass ionomers with that of the other filling materials. Even though it does not deal with the question of durability directly, it is summed up here because issues raised in this review have a bearing on the longevity of the dental fillings.

Randall RC, Wilson NHF. Glass-ionomer restoratives: a systematic review of secondary caries treatment effect. Journal of Dental Research. 1999. 78(2): 628–37.

The article reviews 28 prospective studies that include control groups. Nine of those are either random or quasi-random, or controlled studies. Although the countries in which the studies were carried out are not given, studies were not excluded on linguistic grounds.

The studies reviewed involve 3965 patients, who ran a high risk of contracting secondary caries. The intervention group had received glass ionomer, composite, or amalgam fillings, and the incidence of secondary caries was the outcome investigated.

The results show that there does not seem to be a connexion between the incidence of secondary caries and the type of the dental filling material used. The results fail to show glass ionomers having any greater inhibitory effect on the development of secondary caries than the other filling materials.

The review places the findings in four categories:

• Five studies found no incidence of secondary caries in the group with glass ionomer fillings, but found them in the control group.• Ten studies found no secondary caries either in the glass ionomer or the control group.• Three studies found secondary caries in the glass ionomer group, but not in the control group.• Ten studies found secondary caries in both groups.

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The reviewers conclude that better clinical studies are needed to ascertain the properties of glass ionomers, both those in use today, and newer varieties of the future.

Assessment of the methodology in useSources of the material reviewed include two databases, and technical journals. Language has not been a criterion for exclusion, and clear selection criteria have been provided.

Resin-ionomersOnly one review concerned with resin-ionomers has been found:

Hsee KMY, Leung SK, Wei SHY. Resin-ionomer restorative materials for children: A review. Australian Dental Journal 1999; 44: (1): 1–11)

However, it does not seem to meet our standards of quality, and is therefore not discussed here.

The filling techniquesThe following systematic review works on the relationship between different dental filling techniques applied to deciduous and permanent teeth, and the durability of the dental fillings and the incidence of secondary caries.

McComb D. Systematic Review of Conservative operative Caries Management Strategies. Journal of Dental Education. Vol 65, no 10 2001.

Three different techniques are considered here; tunnelling, minibox, and fissure sealing. However, only the minibox method was assessed in the treatment of caries in deciduous teeth. The filling materials involved were amalgam, composites and glass ionomers.

The studies under review investigate the durability of the fillings, and the incidence of caries. While 16 of those studies were concerned with the deciduous teeth, 28 studies involved permanent teeth. The studies are prospective; the clinical studies are with and without control groups. They were undertaken between 1978 and 1999, but where they were carried out has not been indicated.

Results, tunnel techniqueNine studies carried out between 1992 and 1999 are considered here. Filling material in use was glass ionomer cement, and three of the studies included a control group where amalgam was used. The technique is not suited for the treatment of deciduous teeth.

The technique requires high technical skill. According to the studies involving a long follow-up, the fillings showed a 50% survival rate after 6 years. However, more recent studies indicate a high incidence of associated caries among the recipients of this treatment, as much as 45% after 3 years. The review does not generalise on the results of the 9 studies.

Results, minibox techniqueThree studies carried out between 1995 and 1998, where either amalgam or composites were used, have been reviewed. Comparatively few patients, 14, 37, and 48 were included in those studies.

The follow-up period was 5 or 10 years.

This method is better than the tunnel technique. Compared with conventional class II amalgam or composite fillings, it affords an acceptable survival rate of fillings. The review does not generalise on the results of the three studies.

Results, prophylactic use of compositesThe treatments involved here include minor occlusal fillings and fissure sealing. The article reviews 18 studies, of which 13 are prospective while the remainder are retrospective studies. They were carried out between 1990 and 1999.

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At least during the first five years after the treatment, the method seems to compare favourably with the same procedure carried out using amalgam. Detachment of the sealant appears to be the greatest problem encountered here. The review makes no attempt to generalise on the findings of the studies involved.

Results, fillings in deciduous teeth; glass ionomers and minibox techniqueSixteen studies carried out between 1990 and 2000 are reviewed in the article. These include 12 studies that assess the proximal minibox technique, while the remainder compare the use of glass ionomers in traditional class II fillings and amalgam.

There seems to be a great variation between the results of the studies reviewed. Amalgam appears to be as good as, or better than glass ionomers in class II (failure rate from 0–29,4%), while the other materials generally show lower durability.

ConclusionsMinimal extension does not guarantee a longer life for dental fillings. All dental filling materials have individual material weaknesses, and their durability is influenced by how they are applied and the effect of subsequent caries. Applied in conjunction with regular and adequate dental check-ups, dental restorative techniques that involve minimal extension help to prolong the life of the teeth.

Inadequacies in some of the studies reviewed make it difficult to draw definite conclusions about the issues they investigate. More studies are needed to clarify the issues the review attempted to elucidate.

Assessment of the method in useThe sources of the material reviewed are Medline and Embase. Although the studies chosen for review were said to have been subject to quality control, what selection criteria were applied is not given. Meanwhile, the authors point out the uneven quality of the material under review.

A considerable number of the studies included in the review seem to display inadequacies with respect to control groups, presentation of the case histories and descriptions of carious lesions present, or information on who carried out the treatment. Moreover, the follow-up period used by many studies is often minimal. These render it difficult to make useful generalisations based on the material under review. Minimal interventionThe search for systematic reviews on minimally invasive operative care in Dentistry proved to be less than fruitful. However, the two following reviews were found, which do not seem to address satisfactorily, the issues considered significant here;Peters MC, McLean ME. I. Minimal Intervention and Concepts for Minimally Invasive Cavity Preparations. J Adhesive Dent 2001, 3:7–16 and II. Contemporary techniques and Materials: an Overview. J Adhesive Dent 2001, 3:17–31 .

Question 2: Which substances are released by various types of dental filling materials?This issue is discussed in 11.3.4 below.

Question 3: Are there adverse effects on health of diverse dental filling materials?As it is customary in literature to deal with the substances released by the dental fillings in terms of their adverse effects, the two issues will be taken up together here.

Exposure to Mercury from amalgam, and its effects on healthThere seems to be a scarcity of systematic reviews that deal adequately with this issue. The following seven reviews were carefully assessed:

11.3.4

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Dodes, JE: Dental Silver-Amalgam fillings: are Dentist Poisoning Their Patients? The Scientific Review of Alternative Medicine. Vol 5, No 1 (winter 2001).

Dodes, JE: The amalgam controversy An evidence-based analysis JADA, Vol 132, March 2001(¨Duplikat¨ of Dodes 2001).

Eley, BM: The future of dental amalgam: a review of the literature. Part 5: Mercury in the urine, blood and body organs from amalgam fillings. British Dental Journal, Vol 182, number 11, June 14 1997.

The safety of dental amalgam: a state of the art review - non-systematic review 1997. Sammendrag publisert av NHS Centre for reviews and dissemination.

Cranmer, M: Gilbert, S; Cranmer, J Neuro-toxicity of mercury – Indicatiors and Effects of low-Level expousure: overview Neuro Toxicology 17(1): 9–14,1996.

Halbach, S: Amalgam Tooth Fillings and Man’s mercury Burden. Human & Experimental Toxicology (1994), 13,496–501.

Barregård, L: Biological monitoring of exposure to mercury vapour. Scand J Work Environ Health. 1993; 19 suppl 1:45–9.

The reviews were published between 1993 and 2001. None of these articles provide the source of the materials under review, selection criteria, or the method of assessment used. This lack makes it difficult to exclude personal bias from those selections. These reviews agree that according to the studies reviewed, no adverse effects on health due to amalgam fillings can be shown to exist in populations with such fillings. Meanwhile in some individuals, amalgam may elicit an allergic reaction.

Effect of the substances released by composites on healthOne review of limited quality concerned with this subject has been found:

Søderholm KJ, Mariotti A. BIS-GMA-Based resins in dentistry: are they safe? JADA, Vol 130, February 1999.

The article does not provide the source of the materials under review, selection criteria, or the method of assessment used.

Effect of the substances released by polymers on healthOne review of limited quality dealing with the side effects associated with the use of polymers on patients and dental health professionals has been found:

Geurtsen, W Biocompatibility of resin-modified filling materials. Crti Rev Oral Biol Med 2000; 11(3): 333–355.

The review does not provide the source of the materials under review, selection criteria, or the method of assessment used.

Question 4: What are the effects of various dental filling materials on the working environment of the dental health professionals?

Effects of dental filling materials on the health of dental health professionalsWe could not through our search strategy identify any systematic reviews in this area.

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Question 5: What are the costs of treatment using different dental filling materials?No systematic search for work in this area was undertaken, because the Department of Knowledge Support does not have at present, the competence to make assessments in cost-benefit analysis nor was it possible to get additional support within the time frame.

Other findings

A comparison between the use of pre-formed metal crowns and amalgam in the restoration of deciduous molars.The following systematic review will be considered here:

Randall RC, Vri Jhoef MMA, Wilson NHF. Efficacy of preformed metal crowns vs amalgam restorations in primary molars: a systematic revew. JADA 2000; 131:337–343.

It reviews 10 studies undertaken between 1975 and 1997, which compare the durability of pre-formed metal crown and amalgam used in the restoration of deciduous molars. These consist of 8 retrospective studies involving 4410 children, a controlled study involving 188 children, and a prospective evaluation of 732 children.

The children were between 3 to 7 years of age, and the treatment was given at a dental hospital or a dental paediatric clinic.

The susceptibility to caries among the children involved varied, and some of the children had behavioural problems. The follow-up period varied among the studies, ranging from 1.6 to 10 years. Summary of the resultsAll studies reviewed show that pre-formed metal crowns (PMC) were more durable than amalgam. While the PMC had a failure rate between 1.9% and 30.3%, that of amalgam ranged between 11.6% and 88.7%.

Overall significantly lower failure rates were found for PMC compared with amalgam. Pooled OR = 0.23 (95% CI: 0.19, 0.28). The meta-analysis did not indicate similar results between studies but showed heterogeneity between studies.

Assessment of methodology in useThe inclusion criteria were defined in terms of intervention, participants, and outcome of interest, but the definition of outcome appears to have varied between studies. It is unclear what influence that variability of the definition had on results.

Dependence on only one database and published studies may have led to the omission of other relevant studies and to publication bias. Linguistic restrictions and methods of selection applied to primary studies have not been given.

Soundness of the included studies was not assessed and results were not measured against any standard of adequacy such as study design.

The meta-analysis indicated heterogeneity and thus pooling of results from studies was not appropriate. Several potential sources of clinical heterogeneity between studies have been discussed.

The discussion mentions some potential sources of bias in the evidence presented. While the evidence supports their conclusions, the authors rightly point out that caution is advised in view of the preponderance of evidence based on retrospective studies in which outcomes were variably defined. There is a need for good quality randomized trials.

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11.4 Conclusions

Section 11 sums up some relevant reviews of research papers on different aspects of dental filling materials. This work represents more a critical compilation of readily accessible reviews of research within some areas, rather than a complete and comprehensive assessment of the research undertaken to evaluate various dental filling materials.

However, notwithstanding certain reservations their methodology invites, the reviews and the basic studies involved allow one to draw some approximate conclusions about different dental filling materials and application techniques.

It has been repeatedly pointed out that there is a significant variation in adequacy among the basic studies under review. Their inadequacies are often associated with the requirements such as control groups, case histories, extent of caries, and who provided the treatment, which renders comparisons among them difficult. Moreover, frequently too few patients are included in the basic studies, and the follow-up period seems to be minimal.

We have not been able to identify systematic reviews dealing with certain areas of our inquiry. This does not necessary indicate lack of research in the area concerned, but the lack of good systematic reviews in the area. Our problem here has been the scarcity of works of adequacy for consideration. While many reviewers conclude that the material under review does not permit generalisation owing to various inadequacies, other reviewers seem to deviate from the norms of reviewing. This is a problem common to all disciplines, and it ought to be seen as a serious challenge.

Hence it is important to acknowledge the need for further work concerning various aspects of dental filling materials. This involves primal research with robust designs and systematic reviews of their results. Needless to say, both types of work must be subject to the requirements of scientific and academic rigour. Moreover, both basic research and reviews must be kept as up-to-date as possible.

In our opinion, there is sufficient amount of adequate material dealing with the durability of dental filling materials. Meanwhile in the areas given below, there is either a lack of material, or what is available is of uncertain adequacy:

Possible inhibition of secondary caries by glass ionomers.

Filling techniques.

Comparison of preformed metal crowns with amalgam in the treatment of carious deciduous molars.

We were unable to find adequate reviews dealing with the following areas:

Degree of exposure to mercury associable with amalgam fillings.

Side effects of polymers and composite filling materials.

Effect of dental filling materials on the working environment of dental health professionals.

Minimal extension in cavity preparation.

Polymer based filling materials and health.

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Norwegian Board of HealthOla Johan Basmo, the chairmanLiljan Smith Aandahl, the secretaryPaul Christoffersen

Representative of the County Dental Officers Bjørn Horgen Ellingsen

University of Bergen, Faculty of Dentistry, Department of Dental BiomaterialsRune Eide

Scandinavian Institute of Dental MaterialsJon Dahl

UNIFOB / University of Bergen, Dental Biomaterials Adverse Reaction UnitLars Björkman

Norwegian Dental Association Trond Strandenes

Norwegian Dental Patient AssociationMaryanne RyggJorunn �Østberg

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Reference group responsible for the revision of the draft guidelines in preparation for further discussion at the National Conference on Oral Biomaterials in May 2000.

Scandinavian Institute of Dental MaterialsJon E. Dahl, the secretaryDag �Ørstavik

University of Oslo, Faculty of Dentistry, Department of Cariology Asbjørn Jokstad

University of Bergen, Faculty of Dentistry, Department of Odontology - Gerodontology Gunhild Westerhus Strand

University of Copenhagen, School of DentistryVibeke Qvist

Norwegian Dental AssociationJan AskKari Odland

Representative of the County Dental OfficersMagnar Torsvik

National Insurance AdministrationTore Ramstad

Norwegian Dental Patient AssociationMaryanne Rygg (replacement for Dagfinn Reiersøl)Christer Malmström (nominated by the association)

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Directorate for Health and Social AffairsDepartment of Planning and Professional StandardsFrode ForlandHåkon Lund

Department for Municipal Health and Social ServicesNils Lunder (On secondment from the Public Dental Health Service in Oppland)Liljan Smith Aandahl

Department for Knowledge SupportGro JamtvedtLiv Merete ReinarAnne Seierstad

Consultants

UNIFOB / University of Bergen, Dental Biomaterials Adverse Reaction UnitLars Björkman

University of Bergen; Faculty of Dentistry, Department of Dental BiomaterialsNils Roar Gjerdet

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Scandinavian Institute of Dental MaterialsEystein RuyterArne Hensten Pettersen

University of Oslo, Faculty of Dentistry, Clinic for Adult Oral Health CareOle Skogedal

University of Bergen, Faculty of Dentistry, Department of Dental BiomaterialsNils Roar Gjerdet

Representatives of the County Dental OfficersBjørn EllingsæterTurid Album Alstad

Norwegian Dental AssociationReidun Stenvik

Directorate for Health and Social AffairsKari StorhaugBjørn GuldvogFrode ForlandHans Petter AarsethLiljan Smith AandahlLiv Merete Reinar

Norwegian Dental Patient AssociationAsbjørn Saxegård

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Scandinavian Institute of Dental MaterialsJon E. DahlArne Hensten Pettersen

UNIFOB / University of Bergen, Dental Biomaterials Adverse Reaction UnitLars BjörkmanHelene Tvinnereim

University of Oslo, Faculty of Dentistry, Department of Cariology Morten Rykke

University of Oslo, Faculty of Dentistry, Clinic for Adult Oral Health CareOle Skogedal

University of Bergen, Faculty of Dentistry, Department of Dental BiomaterialsNils Roar Gjerdet

University of Tromsø, Faculty of Medicine, Institute of Odontology Harald Eriksen

Representatives of the County Dental OfficersBjørn EllingsæterBjørn Horgen Ellingsen

Directorate for Health and Social AffairsBjørn GuldvogKirsten PetersenHåkon LundLiljan Smith AandahlLiv Merete ReinarAnne SeierstadNils Lunder (on secondment from the Public Dental Health Service, Oppland)

Norwegian Institute of Public HealthJan Hongslo

Norwegian Dental AssociationReidun StenvikMorten Rolstad

Norwegian Dental Patient AssociationAsbjørn SaxegårdSigny Aarnes

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National Health Service CfRaD, University of York. The Longevity of dental restorations. 19. 2001.

Hickel R, Manhart J. Longevity of restorations in posterior teeth and reasons for failure. J Adhes Dent 2001; 3(1):45–64.

Randall RC, Vrijhoef MM, Wilson NH. Efficacy of preformed metal crowns vs. amalgam restorations in primary molars: a systematic review. J Am Dent Assoc 2000; 131(3):337–343.

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Tveit AB, Espelid I, Skodje F. Restorative treatment decisions on approximal caries in Norway. Int Dent J 1998.

Dahl J, Mjør IA. Fyllingsterapi i Norge - materialvalg, holdbarhet og årsaker til revisjon. Nor Tannlegeforen Tid 2001; 111:552–556.

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Bengtsson C, Ahlqwist M, Bergdahl IA, Lapidus L, Schütz A. Inget samband mellan antal amalgamfyllningar och hälsa. Epidemiologiska erfarenheter från populationsstudie av kvinnor i Göteborg. Läkartidningen 2001; 98(9):930–933.

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University of Bergen, Faculty og Dentistry http://www.uib.no/ood/Pekere/IOBpekere

University of Oslo, Faculty og Dentistry http://www.odont.uio.no/allmennodontologi-voksen

http://www.odont.uio.no/allmennodontologi-barn

NIOM – Scandinavian Institute of Dental Materials http://www.niom.no

The Norwegian Dental Journalhttp://www.tannlegetidende.no/pls/dntt/pa_dtdm.tidende

The Norwegian Center for Health Technology Assessment http://www.oslo.sintef.no/smm Dental Biomaterials: Adverse Reaction Unithttp://www.uib.no/bivirkningsgruppen/

The Swedish Resource Center for Dental Materials (KDM)http://www.sos.se/kdm/

The Swedish Council on Technology Assessment in Health Care http://www.sbu.se

Cooperation of The Swedish Dental Trade Association and The Swedish Dental Association http://www.dentmr.com/

The Nordic Dental Association’s Dental Material Registerhttp://www.dtf-dk.dk/db/materiale/materiale_index.asp

Eastman Dental Institute for oral health care scienceshttp://www.eastman.ucl.ac.uk/

NHS Centre for Reviews and Dissemination http://www.york.ac.uk/inst/crd

Scottish Intercollegiate Guideline Network http://www.sign.ac.uk

Centre for Evidence-Based Dentistry http://www.ihs.ox.ac.uk/cebd

British Dental Journalhttp://www.nature.com/bdj/

Journal of the American Dental Associationhttp://www.ada.org/prof/pubs/jada/index.asp

The ADA Seal of Acceptancehttp://www.ada.org/prof/prac/seal/index.html

Journal of the Canadian Dental Associationhttp://www.cda-adc.ca/jcda/

Web sites were operative in 2003

W E B A D D R E S S E S

Trykkeri: Lobo media 12/2003

Sosial- og helsedirektoratetDirectorate for Health and Social Affairs

P.O. BOX 8054 DepN-0031 Oslo, NorwayTlf.: +47 24 16 30 00Fax: +47 24 16 30 01

www.shdir.no

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