Estrogen receptor gene is associated with dental fluorosis in Brazilian children.

OBJECTIVES: The aim of this study was investigate the association between genetic polymorphisms in ESR1, ESR2, and ESRRB and dental fluorosis (DF) in a well-characterized sample of children from Curitiba, Brazil. MATERIAL AND METHODS: From a representative sample of 538 children, 12-year-old were evaluated. DF was assessed in erupted permanent teeth by the Dean's index modified. Fourteen polymorphisms were selected in intronic and intergenic regions of ESR1, ESR2, and ESRRB and genotyped in genomic DNA source from saliva using TaqMan chemistry and end-point analysis. Allele and genotype distributions between DF and DF free groups were analyzed using the Epi Info 7.2. Chi-square or Fisher's exact tests at a level of significance of 5% and odds ratios calculations with 95% confidence intervals were used to determine the statistical associations. RESULTS: Among 538 children, 147 were DF and 391 were DF free. Genotype distribution for the polymorphism rs12154178 in ESR1 was different between the two groups (p = 0.037; OR = 0.91; CI = 0.67-1.22). The dominant model analysis (AA+AC vs. CC) demonstrated that CC is a protective factor for DF (p = 0.038; OR = 0.51, 0.27-0.97 95% CI). We did not find differences in frequency distributions in the other evaluated polymorphisms. CONCLUSION: This study provides evidence that ESR1 is associated with DF. CLINICAL RELEVANCE: Dental fluorosis is an important condition that affects the mineralized tissues of the teeth. In severe cases, the treatment takes time and is extremely costly. This research provides evidences that there are genetic factors involved in dental fluorosis and will help professionals to plan more precise strategies to reduce dental fluorosis occurrence.

Fine-mapping of 5q12.1-13.3 unveils new genetic contributors to caries.

Caries is a multifactorial disease and little is still known about the host genetic factors influencing susceptibility. Our previous genome-wide linkage scan has identified the interval 5q12.1-5q13.3 as linked to low caries susceptibility in Filipino families. Here we fine-mapped this region in order to identify genetic contributors to caries susceptibility. Four hundred and seventy-seven subjects from 72 pedigrees with similar cultural and behavioral habits and limited access to dental care living in the Philippines were studied. DMFT scores and genotype data of 75 single-nucleotide polymorphisms were evaluated in the Filipino families with the Family-Based Association Test. For replication purposes, a total 1,467 independent subjects from five different populations were analyzed in a case-control format. In the Filipino cohort, statistically significant and borderline associations were found between low caries experience and four genes spanning 13 million base pairs (PART1, ZSWIM6, CCNB1, and BTF3). We were able to replicate these results in some of the populations studied. We detected PART1 and BTF3 expression in whole saliva, and the expression of BTF3 was associated with caries experience. Our results suggest BTF3 may have a functional role in protecting against caries.

Effect of sucrose containing iron (II) on dental biofilm and enamel demineralization in situ.

Since the effect of iron (Fe) on the cariogenicity of sucrose in humans is unexplored, this study assessed in situ the effect of Fe co-crystallized with sucrose (Fe-sucrose) topically applied in vitro on the acidogenicity, biochemical and microbiological composition of the dental biofilm formed in vivo and on the demineralization of the enamel. During two phases of 14 days each, 16 volunteers wore palatal appliances containing blocks of human enamel, which were submitted to four groups of separate treatments: (1) water; (2) 20% sucrose; (3) 20% (w/v) sucrose plus 18 microg Fe/ml, and (4) 20% (w/v) sucrose plus 70 microg Fe/ml. The solutions were dripped onto the blocks 8 times per day. The biofilms formed on the blocks were analyzed with respect to acidogenicity, biochemical and microbiological composition. Mineral loss was determined on enamel by surface and cross-sectional microhardness. Lower demineralization was found in the blocks subjected to Fe-sucrose (70 microg Fe/ml) than in those treated with sucrose (p < 0.05). This concentration of Fe also reduced significantly the populations of mutans streptococci in the biofilm formed on the blocks. In conclusion, our data suggest that Fe may reduce in situ the cariogenic potential of sucrose and the effect seems to be related to the reduction in the populations of mutans streptococci in the dental biofilm formed.