Validation of fingernail fluoride concentration as a predictor of risk for dental fluorosis

The aim of this study was to validate the use of fingernail fluoride concentrations at ages 2-7 years as predictors of the risk for developing dental fluorosis in the permanent dentition. Fifty-six children of both genders (10-15 years of age) had their incisors and premolars examined for dental fluorosis using the Thylstrup-Fejerskov index. Fingernail fluoride concentrations were obtained from previous studies when children were 2-7 years of age. Data were analyzed by unpaired t test, ANOVA, and Fisher's exact test when the fingernail fluoride concentrations were dichotomized (<= 2 or > 2 mu g/g). Children with dental fluorosis had significantly higher fingernail fluoride concentrations than those without the condition, and the concentrations tended to increase with the severity of fluorosis (r(2) = 0.47, p < 0.0001). Using a fingernail fluoride concentration of 2 mu g/g at ages 2-7 years as a threshold, this biomarker had high sensitivity (0.84) and moderate specificity (0.53) as a predictor for dental fluorosis. The high positive predictive value indicates that fingernail fluoride concentrations should be useful in public health research, since it has the potential to identify around 80% of children at risk of developing dental fluorosis. Copyright (C) 2012 S. Karger AG, Basel

Dental fluorosis in the primary dentition and intake of manufactured soy-based foods with fluoride

Background & aims: To identify manufactured soy-based products more recommended by pediatricians and nutritionists; to determine fluoride concentrations in these products; to evaluate children concerning fluorosis in primary teeth and its association with the consumption of soy-based products. Methods: Pediatricians and Nutritionists answered a questionnaire about soy-based products they most recommended to children. Fluoride concentrations of the 10 products more cited were analyzed with the ion-specific electrode. Dental fluorosis exams were performed in 315 4e6-year-old children. Dean’s Index was used to assess fluorosis. Among the children examined, 26 had lactose intolerance. Their parents answered a questionnaire about children’s and family’s profile, besides permitting the identification of soy-based products use. Chi-squared and Multivariable Logistic Regression tests were used (p < 0.05). Results: Fluoride content in the analyzed products ranged from 0.03 to 0.50 mg F /mL. Dental fluorosis was detected in 11% of the children, with very mild and mild degrees. Dental fluorosis in primary teeth was associated with lactose intolerance (p < 0.05), but there was no significant association with the use of manufactured soy-based products. Conclusions: Isolated consumption of soy-based products recommended by health professionals to children do not offer risk of dental fluorosis in primary teeth, which had a low prevalence and severity.

Renal proteome in mice with different susceptibilities to fluorosis

A/J and 129P3/J mouse strains have different susceptibilities to dental fluorosis due to their genetic backgrounds. They also differ with respect to several features of fluoride (F) metabolism and metabolic handling of water. This study was done to determine whether differences in F metabolism could be explained by diversities in the profile of protein expression in kidneys. Weanling, male A/J mice (susceptible to dental fluorosis, n = 18) and 129P3/J mice (resistant, n = 18) were housed in pairs and assigned to three groups given low-F food and drinking water containing 0, 10 or 50 ppm [F] for 7 weeks. Renal proteome profiles were examined using 2D-PAGE and LC-MS/MS. Quantitative intensity analysis detected between A/J and 129P3/J strains 122, 126 and 134 spots differentially expressed in the groups receiving 0, 10 and 50 ppmF, respectively. From these, 25, 30 and 32, respectively, were successfully identified. Most of the proteins were related to metabolic and cellular processes, followed by response to stimuli, development and regulation of cellular processes. In F-treated groups, PDZK-1, a protein involved in the regulation of renal tubular reabsorption capacity was down-modulated in the kidney of 129P3/J mice. A/J and 129P3/J mice exhibited 11 and 3 exclusive proteins, respectively, regardless of F exposure. In conclusion, proteomic analysis was able to identify proteins potentially involved in metabolic handling of F and water that are differentially expressed or even not expressed in the strains evaluated. This can contribute to understanding the molecular mechanisms underlying genetic susceptibility to dental fluorosis, by indicating key-proteins that should be better addressed in future studies

Dental caries associated factors in 12 year-old schoolchildren from a municipality in the state of São Paulo, Brazil

Objective To analyze the possible association between dental caries, fluorosis and the need for treatment in 12 year-old schoolchildren and the socioeconomic conditions of parents/guardians in the city of Franca, in the state of São Paulo. Methods A random sample of schoolchildren aged 12 was obtained from the school records in Franca, using a systematic random technique. The epidemiological survey was carried out by a single calibrated examiner, on 258 public and private schoolchildren in order to obtain the prevalence of dental caries, the need for treatment and the severity of dental fluorosis. Parents/guardians were also interviewed to assess their socioeconomic conditions (education and per capita income). We used multiple correlation analysis to investigate associations between category variables. Results It was possible to identify two distinct groups, with associations between the variables: the first group, represented by schoolchildren with average prevalence of caries, need for treatment, low level of parental education and income; and a second group represented by schoolchildren with low prevalence of caries, no need for treatment, high parental education and income. The two dimensions explained approximately 35% of total inertia. The factors within each group are related. Conclusion High income and parental education are associated with the low prevalence of dental caries but there is no association with dental fluorosis.