Throughout the past 30 years, there has been a decline in dental caries much of which can be attributed to the development, increasing availability and use of effective fluoride dentifrices. In most industrialized countries, the reduction in dental caries has been in the order of 50%. It is important to note that the development costs and the clinical evaluation of fluoride dentifrices has been primarily absorbed by the major manufacturers. Little expenditure has been incurred by governmental or health service agencies. Indeed, it could be argued that the improvement in dental health has been manufacturer led. Manufacturers have continued to invest considerable resources in order to improve the efficacy of fluoride dentifrices available for the benefit of the consumer. It is relevant to briefly review the "milestones" in the development of fluoride dentifrices, as so much has been achieved in such a relatively short time. These milestones may be highlighted by considering them in terms of the progress made in the last three decades. The scientific community, including many of the dental associations of the world, have widely accepted that dentifrices containing either sodium fluoride or sodium monofluorophosphate possess comparable anticaries efficacy. Recently, however, a symposium held in Toronto and published in a special issue of Caries Research has called this into question. This paper reconsiders these data so that the dental profession, the scientific community and the general pubic can make informed decisions as to the relative merits of fluoride dentifrices currently available in world markets.
(Am. J. Dent., Vol. 6, Sp. Iss. 5, 1993)
The 10 pivotal caries clinical studies employed in a recent meta-analysis to compare the anticaries efficacy of sodium fluoride (NaF) and sodium monofluorophosphate (MFP) dentifrices were subjected to a critical review. When reporting the meta-analysis, the author, Johnson, considered these 10 pivotal caries clinical studies as "head-to-head" comparisons of NaF and MFP® dentifrices. For the most part, it is difficult to find any common denominator among these 10 caries clinical studies since there were so many diverse factors associated with them. The 10 pivotal studies were conducted over a 20-year period of time in many different geographic areas of the world, using different protocols and study designs, different clinical examiners and caries assessment criteria, as well as evaluating commercially outdated or specially formulated dentifrices. Any attempt to integrate the results from these 10 studies is further complicated by the diversity of statistical methodology used to evaluate the results obtained from the studies. Also, in two of the 10 studies, the comparison of the fluoride dentifrices was obscured by the fact that the participating children used a fluoride mouthrinse during the course of the study. In any case, when all relevant dentifrice comparisons are made, the results of a critical review of the 10 pivotal ("head-to-head") caries clinical studies indicate a high degree of variability with no clear result.
(Am. J. Dent., Vol 6, Sp. Iss., 13-42, 1993)
A 36-month double-blind clinic-at caries study was conducted to determine the comparative anticaries efficacy of sodium monofluorophosphate (MFP) and sodium fluoride (NaF) as incorporated in dentifrice formulation. The test dentifrices which were utilized are commercially available in the United States and all have been granted the American Dental Association Seal of Acceptance for anticaries efficacy. The study was conducted in accordance with the 1988 Guidelines of the American Dental Association Council on Dental Therapeutics. The two formulations used in the NaF versus MFP® comparison were Colgate® Winterfresh® Gel with 0.76% sodium monofluorophosphate in a silica base and Crest® Regular Flavor Toothpaste with 0.24% sodium fluoride in a silica base. A third commercially-available NaF dentifrice, Colgate Jr.® Toothpaste with 0.243% sodium fluoride in a silica base, was included in the study for further comparison. Schoolchildren residing in Maine, USA received a baseline caries clinical examination and then were randomly assigned to the twice-daily use of one of the three dentifrices which were purchased in the marketplace and repackaged in plain white tubes. Caries clinical examinations were subsequently conducted after 2 and 3 years' use of the dentifrices. A total of 2,222 children participated in both the 2 and 3-year caries clinical examinations. The 36-month DFS (decayed and filled surfaces) and the DFT (decayed and filled teeth) mean caries increments for the three dentifrice groups were virtually identical. The children using the MFP® formulation experienced a DFS of 1.50 and a DFT of 1.08; those using the Crest NaF formulation experienced a DFS of 1.48 and a DFT of 1.07; subjects in the third group (Colgate Jr.® Toothpaste, 0.243% NaF) had a DFS of 1.49 and DFT of 1.06. The statistical evaluation of the data consisted of the calculation of 90% confidence bounds for the ratio of (true) mean increments, in accordance with the 1988 American Dental Association Guidelines. Expressed in the language of the Guidelines, the analyses indicated that, (1) the anticaries efficacy provided by the MFP® formulation, (Colgate® Winterfresh® Gel with 0.76% MFP) is "as good as" that provided by the NaF formulation, (Crest® Regular Flavor Toothpaste, with 0.243% NaF), and (2) the anticaries efficacy provided by the one NaF formulation (Colgate Jr.® Toothpaste, with 0.243% NaF) is 11 as good as" that provided by the other, (Crest® Regular Flavor Toothpaste, with 0.243% NaF).
(Am. J Dent., Vol 6, Sp. Iss. 7-12, 1993.)
Studies were conducted to determine fluoride availability in saliva after dentifrice use and to relate this parameter to cariostatic efficacy in rat caries experiments. Three dentifrices-two commercial formulations (Colgate® Winterfresh® Gel and Crest® Dentifrice with Na-Sr-polyacrylate) and an Experimental dentifrice-were compared with respect to salivary fluoride availability. All of the dentifrices tested contained 1100 ppm F- as sodium fluoride. It was observed that the Experimental dentifrice and Crest® dentifrice with Sr-polyacrylate exhibited low salivary fluoride availability relative to the Colgate® Winterfresh® Gel. Salivary fluoride availability was assessed by means of two parameters: (a) the fluoride concentration in the dentifrice saliva slurry expectorated after brushing, and (b) the area under the curve of salivary F- concentration vs. time for up to two hours after dentifrice use. In two rat caries experiments, it was observed that both the Experimental dentifrice and the Sr-polyacrylate dentifrice provided less cariostatic efficacy than the clinically validated Positive Control (Colgate® Winterfresh® Gel). Analysis of these data provides further evidence in support of the concept that fluoride availability in saliva following dentifrice vise is an important parameter related to anticaries efficacy.
(J Dent Res, Vol.71, Sp. Iss., 541-845, 1992)
For practical reasons, evaluation of topical fluoride products must depend upon clinical and laboratory assessments. While not always a good predictor of clinical efficacy by itself, fluoride uptake is the most commonly used laboratory test. A consideration of the relationship between possible anticaries mechanisms of fluoride, different product types, and the meaning of various kinds of fluoride uptake data suggests that both the amount of fluoride taken up by early lesions and the amount of ambient fluoride present at a cariogenic site may play key roles in determining the efficacy of a product. While formulations applied annually or semi-annually probably depend on fluoride deposition, those used daily might not. There are no clear data supporting the superiority of one fluoride compound over another, even for infrequently used products, although there are significant differences among them in fluoride uptake by enamel. This suggests that fluoride uptake in vivo at a cariogenic site might actually be different from that suggested by in vitro data, or that larger differences are required for a clinical effect to be observable. Clinical data support the conclusion that a large increase in the fluoride concentration of a product will somewhat increase its anticaries effectiveness, although the increase will nor be linearly related to concentration. There also are no obvious differences in clinical effectiveness caused by the addition of gelling agents to topical solutions. Fluoride varnishes are clinically effective but have not been shown to be superior to topical solutions or gels.
The abrasive, humectant, and thickener systems used in most prophylaxis pastes reduce both fluoride uptake and clinical effectiveness, even though, in some cases, the components may be chemically compatible. Precleaning prior to a topical application appears unnecessary, but a delay in rinsing after the application and longer application times appear beneficial. Mouthrinse formulations essentially differ only in fluoride source, concentration, and pH. Higher fluoride concentrations are likely to provide greater benefits, but pH differences probably will not. The stannous ion in SnF2 rinses is unstable, and its effect on anticaries activity is unknown.
This review of the composition of topical fluoride products emphasizes the lack of clear evidence for the making of definite scientific judgments regarding relative clinical efficacy. Future efforts should be directed toward the development of test models that utilize the natural oral environment, so that more precise and valid comparison of compositions may be made.
(J Dent Res, Vol 69, Sp Iss, 771-779, 1990)
This report summarizes the findings from eight individual remineralization studies that used the thin-section sandwich model. This model uses thin sections of human enamel (or dentin) containing caries-like lesions sandwiched between sheets of thin plastic which are then implanted into the buccal surfaces of molars in removable partial mandibular dentures. Toothbrushing with a sodium fluoride-positive control dentifrice for two-week periods always produced positive remineralization of the lesions, and similar use of a placebo always produced mean mineral loss. In most studies, the difference was significant at p < 0.01. However, variation among specimens placed within an individual mouth were often large and even included cases where one lesion gained mineral while a closely adjacent lesion lost mineral. Similarly, mean mineral changes produced by an individual subject were not consistent from study to study and ranged from net demineralization in one study to net remineralization in another study. Nevertheless, mean mineral changes from all eight studies showed that all subjects produced more remineralization than demineralization when using a sodium fluoride-positive control dentifrice. Data are presented showing remineralization of thin-section lesions from a number of other fluoride and non-fluoride dentifrices and mouthrinses and showing that a product with reduced anti-caries activity (as measured by several tests) also resulted in reduced remineralization by the thin-section model.
(J Dent Res, Vol. 71, Sp. Iss., 850-855, 1992)