Relação entre fluorose dental e a concentração de flúor no dente ? um estudo em área endêmica / The relat ionship between denta l fluorosis and toot h fluoride concentrat ion ? A studyn in an endemic area

Objective: To determine the relationship between dental fluorosis (DF) severity and fluoride [F] concentration in tooth and water in DF endemic areas. Methods: Life-long residents from two DF endemic communities were studied. Forty-five extracted teeth were collected and analyzed for DF severity and tooth [F]. Thylstrup-Ferjeskov Index (TFI) was used to measure DF severity and instrumental neutron activation analysis (INAA) for tooth [F] concentration. Water from regional wells was also collected (n=9) and analyzed for F content using specific ion F electrode. Results: Water [F] varied between 0.2ppm and 4.7ppm. TFI scores ranged from 0 to 6; [F] from 120ppm to 2,140ppm in enamel and 304ppm to 4,800ppm in dentin. No correlation was found between DF severity and [F] in enamel (rs=0.22,p=0.15) and dentin (rs=-0.19,p=0.20), nor between water [F] and [F] in enamel (rs=-0.09,p=0.65) and dentin (rs=-0.11,p=0.56). Weak correlation between DF severity and water [F] (rs=0.38,p=0.04) was found. Linear regression analysis showed that TFI couldn?t be predicted from a linear combination of the independent variables (age, enamel and dentin [F]). When enamel, dentin and water [F] were used as independent variables in the linear regression (predict DF severity), only water [F] showed influence in DF severity (p=0.013;t=2.67). Conclusion: Even in areas of endemic DF, tooth [F] didn?t correlate with DF severity and the relationship between water [F] and DF severity was very weak. Therefore, tooth [F] may not be a good predictor/indicator of DF severity.

Objetivo: Determinar a relação entre severidade de fluorose dental (FD), e concentração de flúor [F] no dente e água em áreas endêmicas de FD. Métodos: Residentes de duas comunidades endêmicas de FD foram estudados. 45 dentes foram coletados e analisados para severidade de FD e concentração de flúor. O índice de Thylstrup-Ferjeskov (TFI) foi utilizado para medir a severidade de FD e análise por ativação com nêutrons (AAN) para concentração de [F] dental. Águas de poços da região foram coletadas (n=9) e analisadas para [F], utilizando eletrodo específico de flúor. Resultados: Concentração de [F] da água variou entre 0,2 e 4,7ppm. Os escores do TFI variaram entre 0 e 6; [F] no esmalte entre 120 e 2140ppm e na dentina entre 304 e 4800ppm. Não se observou correlação entre severidade de DF e [F] no esmalte (rs=0,22,p=0,15) e dentina (rs=-0,11,p=0,56). Encontrou-se correlação fraca entre FD e [F] na água (rs=0,38,p=0,04). Análise de regressão linear demonstrou que TFI não podia ser predito por uma combinação linear das variáveis (idade, e concentração de flúor no esmalte e dentina). Quando a concentração de flúor no esmalte, dentina e água foram analisadas de forma independente na regressão linear, apenas flúor na águademonstrou influência na severidade de FD (p=0,013;t=2,67). Conclusão: Mesmo em áreas endêmicas de FD, concentração de flúor dental não se correlaciona com severidade de FD, e a relação entre este e a concentração de flúor nas águas foi fraca. Assim, concentração de flúor dental pode não ser um bom preditor/indicador de severidade de FD.

Fluoride's effect on human dentin ultrasound velocity (elastic modulus) and tubule size.

Despite fluoride (F) use in caries prevention, not much is known about its effects on tooth quality. This study evaluated the effect of tooth F concentration ([F]) on selected dentin structural and mechanical properties. Third molars (n = 136) from Toronto, which has 1 part per million (p.p.m.) water [F], Montreal (0.2 p.p.m. water [F]), and Fortaleza (Brazil) (0.7 p.p.m. water [F]), were analyzed for [F], dental fluorosis (DF) severity, ultrasound velocity, and dentin tubule size and density. The enamel [F] was found to vary between 32 and 940 p.p.m., the dentin [F] was found to vary between 110 and 860 p.p.m., while the DF severity varied between TF0 and TF4. The enamel [F] showed no correlation with dentin [F], DF severity, ultrasound velocity, dentin tubule size or density. The dentin [F] correlated with DF severity, dentin tubule size, and ultrasound velocity. DF severity showed a correlation with dentin [F] and ultrasound velocity. It was concluded that dentin [F] is an indicator of dentin structural properties (dentin tubule size and ultrasound velocity), while DF severity is an indicator of dentin mechanical properties (ultrasound velocity).