Influence of diet and fluoride on dentin and enamel deposition and maturation in rats

Diet and fluoride can modify tooth-germ development. In many morphological and biochemical studies malnutrition was shown to impair odontogenesis. However, quantitative observations of the morphological changes implemented by underfeeding and fluoride are still scanty. The aim of the study was to assess stereologically the enamel and dentin deposition in tooth-germ of 14-day-old rat pups derived from dams fed with deficient diet and given water without or with low (10 mg/l) and high (110 mg/l) doses of natrium fluoride, starting from the 13th day of pregnancy. The volume fractions of ameloblasts, enamel, dentin and odontoblasts in histological sections were estimated by the point counting method. The lack of fluoride in drinking water in rats maintained on low-protein diet changed the proportions of the deposited dental mineralised tissues as compared to the control animals: it substantially increased deposition of enamel (by 48%), and significantly decreased dentin production (by 28%). The supplementation of drinking water with fluoride in rats fed with deficient diet partially reversed these effects towards values found in the control rats maintained on standard diet that drank water with trace amount of fluoride. The possible toxic activity of high doses of fluoride can only be conferred to the decreased volume fraction of ameloblasts. Our findings suggests an important role of the fluoride ion in the maintenance of the proper enamel and dentin relation in the developing teeth of rats fed with low-protein, low-fat, high-carbohydrate diet.