Faculty Bibliography

Over 500 residents of Tecumseh, Michigan, were dentially examined in 1959 as part of a community-wide health study. In 1987, the dental examinations were repeated, with use of the same criteria as in 1959, for 167 dentate persons from the original group. Another 28 reported by telephone that they had become edentulous since 1959. This report uses a historical cohort analysis for exploration of the risk factors for tooth loss, both total and partial, over the 28-year period. Over that time, the edentulous lost an average of 18.0 teeth (95% confidence interval 15.5, 20.7), whereas the age-matched 90 dentate persons lost only 3.2 (2.2, 4.2) teeth each. Descriptive data showed the edentulous to have higher baseline scores for plaque, calculus, and gingivitis, and a higher proportion of them smoked, though only loss of periodontal attachment (LPA) of 4 mm or more, early loss of first molars, and educational attainment were significant risk factors in regression analysis. Odds ratios for these three variables were 4.0 (1.2, 12.8), 2.0 (1.3, 3.1), and 0.6 (0.4, 0.9), respectively. The strongest risk factors for partial tooth loss among 116 dentate persons were baseline gingivitis (which was correlated with LPA of 4 mm or more) and the baseline number of teeth present, with odds ratios of 2.4 (1.2, 5.2) and 0.8 (0.7, 1.0), respectively. While the analysis had to be carried out without caries data, it was concluded that total tooth loss is a social-behavioral issue as much as it is disease-related. Social-behavioral factors were less clearly related to partial tooth loss in dentate persons; oral disease characteristics were the most prominent risk factors for partial tooth loss.

The widespread availability of fluoride from many sources is accepted as a major reason for the caries decline among children in developed countries. There is still controversy, however, about its principal mode of action. This article reviews the evidence on fluoride's preeruptive and posteruptive effects, and suggests reasons for its continuing role in the caries decline. Early fluoridation studies accepted that fluoride acted preruptively through incorporation into developing enamel; but further research could not explain why fluoride levels were not clearly higher in enamel exposed to fluoride, nor why there were no clear correlations between caries experience and enamel fluoride concentration. Instead, considerable evidence suggests that fluoride acts mainly, though not entirely, through posteruptive remineralization of demineralized enamel. Caries experience has declined in nonfluoridated as well as in fluoridated areas, though DMF scores are still consistently lower in fluoridated areas. Posteruptive remineralization effects are seen from fluoridated drinking water as well as with fluoride from other sources. The continuing caries decline, beyond the level suggested by early fluoridation field trials, can be attributed either to more efficient remineralization or to long-term, intraoral ecological change, or to both.

Recent questions about the effectiveness of water fluoridation have come from Diesendorf in Australia and Colquhoun in New Zealand. This report examines the arguments of both authors in detail and finds errors in each. Diesendorf employed an outdated view of how fluoride exerts its anticariogenic action and took a number of quotations out of context. Colquhoun's data are questionable. Neither author has produced evidence to challenge the established safety and effectiveness of water fluoridation.