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ABSTRACT
Despite some studies correlating dental fluorosis (DF) and fluoride (F) concentration in dental enamel, no information is available about DF and dentin F concentration. Our objective was to determine the correlation between teeth F concentration and DF severity in unerupted human 3rd molars, and the correlation between dentin and enamel F concentrations in the same tooth. Ninety-nine 3rd molars were studied-53 from Fortaleza, Brazil (F water, 0.7 ppm), 22 from Toronto (1.0 ppm), and 24 from Montreal (0.2 ppm). DF severity was evaluated according to the Thylstrup-Fejerskov Index, while F concentration was analyzed by Instrumental Neutron Activation Analysis. DF severity varied between TF0 and TF4, while F concentration ranged between 39 and 550 ppm in enamel and 101 and 860 ppm in dentin. Our results showed correlation between dentin F concentration and DF (r^sub s^ = 0.316, p = 0.001), but no correlation between enamel F concentration and DF (r^sub s^ = 0.154, p = 0.133). No correlation was observed between dentin and enamel F concentrations in the same tooth (r^sub s^ = 0.064, p = 0.536).
KEY WORDS: fluoride, dentin, enamel, dental fluorosis.
Received December 18, 2002; Last revision September 24, 2003; Accepted November 4, 2003
INTRODUCTION
Dental fluorosis (DF) is a tooth malformation believed to be caused by chronic ingestion of high levels of fluoride (F) during tooth development (Murray et al., 1991a; Den Besten, 1994). However, in addition to the major risk factors previously identified (related to ingestion of F) (Mascarenhas, 2000), other factors, such as genetic susceptibility, have also been shown to be important (Everett et al., 2002) in DF prevalence. DF prevalence has increased throughout the world (Angmar-Mansson et al., 1994), ranging between 7.7% and 80.9% in areas with fluoridated water and between 2.9% and 42% in areas without fluoridated water (Clark, 1994; Mascarenhas, 2000; Pendrys, 2000; Everett et al., 2002).
Few studies have analyzed the F concentration and distribution in mineralized tissues (Richards et al., 1977, 1989, 1992; Olsen and Johansen, 1978). It has been shown, for example, that F concentration is higher in cementum followed, respectively, by alveolar bone, dentin, and enamel (Kato et al., 1990; Ishiguro et al., 1994). Differences between F concentrations in the enamel surfaces of various tooth types in...