No abstract

The present study describes the histological features of enamel in teeth showing either mild or severe fluorosis. Sections were examined in transmitted and polarized light after imbibition in aqueous media or alcohols and quinoline. For semiquantitative study contour maps were prepared. Furthermore quantitative imbibition studies were performed along a traverse through the enamel and at selected points. From the values of total path difference, birefringence was calculated and imbibition graphs drawn. Finally, contact microradiographs were made. The study showed that it is only possible to correlate the degree of histological change with clinical features in severe cases of dental fluorosis. The general morphology of fluorosed enamel does not differ from normal enamel, but the tissue comprise areas of diffuse hypomineralization. In polarized light, opposite to microradiography, much more extensive changes were observed. Thus, slight degrees of dental fluorosis were recorded only when using polarized light. In severe cases, a maximum degree of 25% porosity or more were recorded and located immediately deep to a well-mineralized enamel surface. In severe cases of fluorosis, only dark zones were observed when examined in quinoline, and the quantitative imbibition studies showed that the enamel in these cases reacted similar to what is described in initial caries lesions. In both slight and severe dental fluorosis the subsurface porous region behaved as a ‘mixed body’ in aqueous media, but when examined in alcohols, these could only penetrate the tissue completely in severe cases. Thus, in mild dental fluorosis the subsurface region behaved as a ‘molecular sieve’. The findings in the present study are correlated to previous observations of enamel formation in order to explain the pathogenesis of dental fluorosis.

While there is broad consensus in the research community that fluoride dentifrices provide important anticaries benefits, debate still remains as to the most efficient form of fluoride used in toothpastes. Recently, the authors of this paper collaborated as part of a scientific advisory group whose objective was to comprehensively review all clinical information available comparing the anticaries efficacy of the two agents most widely used in fluoridated toothpastes, sodium fluoride (NaF) and sodium monofluorophosphate (SMFP). This review included a detailed analysis of each published study pertinent to the question, a comprehensive meta-analysis of all available clinical findings, and an epidemiological assessment of how anticaries benefits of dentifrices may be anticipated to propagate with time. Overall, the use of meta-analysis of head-to-head clinical comparisons between the two fluoride-active systems was found to be the most valid means for comparing the relative efficacy of NaF and SMFP dentifrices. Results of this analysis demonstrated that NaF was significantly more effective than SMFP in preventing caries (p < 0.01). While the numerical difference in efficacy between NaF and SMFP measured between 5 and 10% (total DMFS) over a 2- to 3-year clinical period, this could be expected, on theoretical grounds, to propagate to substantially larger differences (e.g. 10–20%) over 10–20 years. Hence, the difference in efficacy between these two actives was judged to be clinically important as well as statistically significant. Based upon these findings the authors recommend that NaF be used as the active system in fluoridated dentifrices whenever practically feasible. However, the authors caution that this recommendation pertains to the formulation of NaF in highly compatible abrasive systems, which must be demonstrated by critical evaluation of ionic fluoride within formulations for stability, availability and bioavailability. One additional recommendation emanating from this review is that important improvements must be made in the design, execution and reporting of future caries clinical trials in order to bring these important methods up to scientifically acceptable standards.

– The present paper describes a standardized system for diagnosing, recording and analyzing dental caries data, based on diagnostic criteria previously described. Each surface is examined, and the diagnosis is coded on punch cards and processed by computer. Different diagnostic levels can be used in diagnosis or analysis depending on the purpose of the study. Data can be analyzed using one or more programs contained in a program library. The advantage of this system in comparison with others seems to be the high degree of flexibility, making it possible to employ the system in many different types of studies (longitudinal clinical trials as well as cross‐sectional epidemiologic surveys).

– In the eastern part of Java and on the island of Bali betel chewing is a very common habit confined principally to females. The purpose of the present study was to examine the influence of betel chewing on the prevalence of dental caries. The study, which is based upon 982 villagers, indicates a strong inverse relationship between the prevalence of dental caries and the intensity of betel chewing. The possible mechanisms whereby betel chewing may have a caries‐inhibiting effect are discussed.