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An experimental investigation has been made into the possibilities of retarding the progress of carious attack by infiltrating cariostatic material into enamel lesions. The problems associated with this kind of procedure are discussed against the background of experimental observations made using a formulation based on a resorcinol-formaldehyde resin.

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The rise and fall of caries prevalence (DMFT) and its relation to changing F concentration of drinking water and other health-related factors is analysed based on dental findings of more than 286,000 subjects of either sex (6–15 years old) from the two industrial towns Chemnitz and Plauen. Water fluoridation (1.0 ± 0.1 ppm F) was implemented in Chemnitz (formerly Karl-Marx-Stadt) in 1959. It was in operation until autumn 1990 with an interruption lasting 22 months around the year 1971. In the F-poor town of comparison, Plauen, 55% of the citizens were supplied with F-enriched drinking water (0.9 ppm F) during the years 1972-1984. Another 20% received F-containing mixed water (0.4–0.7 ppm F). During the first three decades of the study the level of caries prevalence was strictly correlated with the availability of an optimal caries preventive F concentration in the drinking water. Water fluoridation was followed by a decrease of caries, and interruptions in fluoridation were followed by increasing caries levels. A different caries trend was observed in the years from 1987 to 1995. There was a significant caries decrease down to the lowest DMFT (2.0) since 1959 in spite of the fact that only F-poor water was available over years in both towns. This improvement of oral health is explained by changes in caries-preventive and environmental conditions.

In contrast to the anticipated increase in dental caries following the cessation of water fluoridation in the cities Chemnitz (formerly Karl-Marx-Stadt) and Plauen, a significant fall in caries prevalence was observed. This trend corresponded to the national caries decline and appeared to be a new population-wide phenomenon. Additional surveys (N=1017) carried out in the formerly-fluoridated towns of Spremberg (N=9042) and Zittau (N=6232) were carried out in order to support this unexpected epidemiological finding. Pupils from these towns, aged 8/9-, 12/13- and 15/16-years, have been examined repeatedly over the last 20 years using standardised caries-methodological procedures. While the data provided additional support for the established fact of a caries reduction brought about by the fluoridation of drinking water (48% on average), it has also provided further support for the contention that caries prevalence may continue to fall after the reduction of fluoride concentration in the water supply from about 1 ppm to below 0.2 ppm F. Caries levels for the 12-year-olds of both towns significantly decreased during the years 1993-96, following the cessation of water fluoridation. In Spremberg, DMFT fell from 2.36 to 1.45 (38.5%) and in Zittau from 2.47 to 1.96 (20.6%). These findings have therefore supported the previously observed change in the caries trend of Chemnitz and Plauen. The mean of 1.81 DMFT for the 12-year-olds, computed from data of the four towns, is the lowest observed in East Germany during the past 40 years. The causes for the changed caries trend were seen on the one hand in improvements in attitudes towards oral health behaviour and, on the other hand, to the broader availability and application of preventive measures (F-salt, F-toothpastes, fissure sealants etc.). There is, however, still no definitive explanation for the current pattern and further analysis of future caries trends in the formerly fluoridated towns would therefore seem to be necessary.

Marked erosion at the mesial edges of upper front teeth was observed during an examination of Cuban children. The preferential erosion of mesial edges produced characteristic V-shaped defects on upper central incisors, and the aim of the present study, carried out on 12-yr-old children (N = 1010) in 10 communities in the Province of Havana was to establish the frequency of dental erosion and explain its occurrence. The symmetrical erosion of teeth 11 and 21 (excluding crown injuries and attrition) were clinically classified into four grades: 0.5 = objectionable; 1 = abnormal mesial shortening of incisal edges; 2 = V-shaped defect of cutting edges; 3 = exposure of dentine and extension of the erosive defect to the lateral incisors. In four of the communities, children did not show or rarely showed incisal erosion. In the other six communities, the frequency was surprisingly high (16.6-40.9%). Overall, 17.4% of children exhibited erosion, and the occurrence was significantly higher in girls (20.7%) than in boys (15.0%). The typical V-shaped pattern of erosion seems to be a consequence of the manner in which citrus fruits are eaten. There was also a positive correlation between the frequency of dental erosion and the proximity of citrus plantations, which presumably related to the extent of (daily) orange consumption.

Our results show that the vaccine is safe and effective and should be recommended to TXL-R.