NIH: Consensus Development Conference on Diagnosis and Management of Dental Caries Throughout Life: Background

Elizabeth T. Treasure, B.D.S., Ph.D., FRACDS, FDSRCS:

The diversity of Europe is such that it is not possible to present one point of view as the European perspective. The use of fluoride across Europe varies greatly, from countries with fluoridation of public water supplies and household salt to countries where there is considerable use of topical fluorides to still others where the emphasis is on fluoridated toothpaste. The differences in the delivery of dental services also vary from emphasis on independent practitioners to employment of practitioners in salaried agencies. There are also wide variations in the importance given to a population approach to the prevention of disease. In essence, then, the discussion I give you has to be influenced by my background, which is that of a British practitioner of dental public health with considerable experience in undertaking systematic reviews.

The aims of this presentation are:

• To identify if any studies were missed by the RTI
• To discuss the limitations identified
• To make recommendations for future research.

The first task was to identify any studies that were missing from the review. This was undertaken in the following way:

• The searches were repeated, using slightly different key words

• The searches were limited to MEDLINE and excluded languages other than English as well as the grey literature.

• The abstracts were scanned against the inclusion criteria, and when the papers appeared to meet the inclusion criteria, they were read.

Two additional papers were found that, in my opinion, fulfilled the inclusion criteria. The first (Bruun, Bille, Hansen, et al., 1985) compared a 0.2 percent sodium fluoride rinse with a difluorosilane varnish using radiographs on the approximal surfaces of molar and premolar teeth. The progression of initial lesions was slightly less in the varnish group, but statistical tests were not reported for this analysis.

The second paper (Forsman, 1974) reported a comparison of 0.2 percent sodium fluoride with 0.025 percent sodium fluoride, both used as a weekly rinse. The author reports the surprising conclusion that the 0.025 percent solution was more effective at preventing caries than the 0.2 percent solution. The picture becomes more confusing when examination focuses on initial lesions. More initial lesions progressed with the lower concentration, but more also regressed with it. Again, statistical tests were not reported for this analysis.

These two additional studies do not add much to those cited in the main report. The total number of studies only increases from five to seven, and there remain the very varied study design and population characteristics with which to contend. They do not alter the conclusions of the main report.

Several issues were identified for discussion. A conflict in outcome measures was found, but the outcome measures commonly reported in clinical trials were not those that this review was looking for. This has to lead to recommendations for future research. The second problem�the ability to measure initial dental caries�has been reviewed in detail in the first part of this conference. Only if this can be done accurately in a clinical setting is it possible to evaluate accurately the effect of any clinical intervention on initial lesions.

From a European perspective, fluoride toothpaste is seen as the major item in control of caries, both at an individual level and in the public health approach. Most would only wish for a clinical method that produced better results than the use of fluoridated toothpaste by an individual. There are sound practical and ethical reasons for taking this approach. With the exception of Scandinavia, it is not possible to envisage a situation in Europe where professional application of fluoride would be available on a very frequent basis except to specific high-risk groups.

Several areas are suggested for future research. The first is to identify suitable study designs for answering this question. It is necessary that this should be specified in some detail, including the study populations to be used, the data that need to be recorded, and the confounding variables that should be considered. As suggested in the report, radiographic studies need to be reanalysed where possible, using the criteria decided in the earlier part of this conference, although the methodological problems of doing this need examination.

The third research task should be completion of further systematic reviews. These should pose slightly different questions and use different inclusion criteria. The first would look at caries preventive methods using �in situ� methodology. Although this is an unusual suggestion for a systematic review, it would be of benefit here as a way of suggesting which techniques might be most promising to test in a clinical setting.

The second review would look at the effects of fluoridated toothpaste on caries in general and on initial caries in particular, while the third would look at the effects of topical fluorides on caries in general. Protocols for these are currently registered with the Cochrane Collaboration. The problems caused by the great heterogeneity of the existing studies are large, and that is something that needs to be considered in future research.

Once these tasks are finished, it will then be possible to commission appropriate research designed to fill in the lacunae identified by the reviews. These would fulfil the criteria identified in the first piece of research on study design. By planning the research in this way, it would be possible to reduce greatly the heterogeneity between studies and allow studies to be combined.

References

Bruun C, Bille J, Hansen KT, Kann J, Qvist V, Thylstrup A. Three-year caries increments after fluoride rinses or topical applications with a fluoride varnish. Comm Dent Oral Epidemiol 1985;13:299�303.

Forsman B. The caries preventing effect of mouthrinsing with 0.025 percent sodium fluoride solution in Swedish children. Comm Dent Oral Epidemiol 1974;2:58�65.

Additional papers for evidence table

Abstracts Index