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Dental fluorosis (DF) is an enamel malformation related to fluoride (F) ingestion. DF may, depending on its severity, influence tooth quality (hardness and mineralization). Poor correlation between tooth F concentration and DF severity was shown. Even when a correlation was present, tooth F concentration explained very little of DF severity. This fact calls into question the generally accepted hypothesis that the main factor responsible for DF severity is tooth F concentration. We believe that genetic factors (susceptibility to DF) play an important role in DF severity. DF severity relates to individual susceptibility to F (genetics) while tooth F concentration relates to F ingestion (environmental). Objectives: The objective of this study was to investigate the correlation between tooth F concentration, bone F concentration, tooth DF severity and tooth quality. Methods: Three inbred strains of mice (previously shown to have different susceptibility to DF) were given four different levels of F in their water (0, 25, 50 and 100ppm). Teeth and bone were tested for F concentration (INAA). Teeth were tested for DF severity (QLF), and tooth quality (microhardness and mineralization). Results: Water F concentration correlated with tooth F concentration but not with DF severity. Correlation was observed between DF severity and tooth F concentration (r=0.583); DF and enamel microhardness (r=-0.640); and DF and dentin microhardness (r=0.424). No correlation was seen between DF and dentin mineralization. Correlation was seen between tooth F concentration and enamel microhardness (r=0.516), and tooth F concentration and dentin mineralization (r=0.245). No correlation was seen between tooth F concentration and dentin microhardness. Conclusion: Environmental (F concentration in tooth structure) and genetic (DF severity) factors influence tooth quality. Genetic factors had a greater affect on tooth biomechanical property (microhardness), while environmental factors had a stronger influence on tooth material property (mineralization). (NIDCR DE014853-01A1 support to ETE) |