Effectiveness of pit and fissure sealants on primary molars: A 2-yr split-mouth randomized clinical trial

The primary objective of this study was to evaluate the effects of sealants in preventing pit and fissure caries in primary molars. The secondary objective was to assess the sealant retention during a 2-yr study period. A 2-yr split-mouth randomized clinical trial including 90 3-7-yr-old children was conducted in the paediatric dental department of Montpellier hospital. The dentition of each included patient was divided into an experimental side and a control side, with annual follow-up visits. Caries increments, measured as the number of new occlusal cavitated lesions, were not different between the sealed (mean 0.23) and the control primary molars (mean 0.29). A multiple mixed-effects logistic regression showed that male gender, moderate/high caries risk, and a higher oral hygiene index score, had a statistically significant effect resulting in higher caries increments in the primary molars, than did female gender, low caries risk, and lower oral hygiene index scores. Sealing showed no statistically significant influence on the development of new caries lesions. After 2 yr, the percentages of partially or totally lost sealants were 22.7% and 32.0%, respectively. In this sample of children, the caries increment was not significantly different between the sealed and the unsealed molars. At the end of this 2-yr study, more than half of the sealants were totally or partially lost, which could explain the low sealant effectiveness.

Dental caries and enamelin haplotype

In the literature, the enamelin gene ENAM has been repeatedly designated as a possible candidate for caries susceptibility. Here, we checked whether ENAM variants could increase caries susceptibility. To this aim, we sequenced coding exons and exon-intron boundaries of ENAM in 250 children with a severe caries phenotype and in 149 caries-free patients from 9 French hospital groups. In total, 23 single-nucleotide polymorphisms (SNPs) were found, but none appeared to be responsible for a direct change of ENAM function. Six SNPs had a high minor allele frequency (MAF) and 6 others were identified for the first time. Statistical and evolutionary analyses showed that none of these SNPs was associated with caries susceptibility or caries protection when studied separately and challenged with environmental factors. However, haplotype interaction analysis showed that the presence, in a same variant, of 2 exonic SNPs (rs7671281 and rs3796704; MAF 0.12 and 0.10, respectively), both changing an amino acid in the protein region encoded by exon 10 (p.I648T and p.R763Q, respectively), increased caries susceptibility 2.66-fold independent of the environmental risk factors. These findings support ENAM as a gene candidate for caries susceptibility in the studied population.

Common SNPs of AmelogeninX (AMELX) and dental caries susceptibility

Genetic approaches have shown that several genes could modify caries susceptibility; AmelogeninX (AMELX) has been repeatedly designated. Here, we hypothesized that AMELX mutations resulting in discrete changes of enamel microstructure may be found in children with a severe caries phenotype. In parallel, possible AMELX mutations that could explain resistance to caries may be found in caries-free patients. In this study, coding exons of AMELX and exon-intron boundaries were sequenced in 399 individuals with extensive caries (250) or caries-free (149) individuals from nine French hospital groups. No mutation responsible for a direct change of amelogenin function was identified. Seven single-nucleotide polymorphisms (SNPs) were found, 3 presenting a high allele frequency, and 1 being detected for the first time. Three SNPs were located in coding regions, 2 of them being non-synonymous. Both evolutionary and statistical analyses showed that none of these SNPs was associated with caries susceptibility, suggesting that AMELX is not a gene candidate in our studied population.

[The impact of socioeconomic status in the estimation of non-adult dental age]

The aim of this study is to observe the possible impact of socioeconomic level on stages of macroscopic dental development. The sample consists of 456 children from European origin, aged 3.5 to 16 years (242 girls and 214 boys). We apply a radiographic method of non-adult dental age estimation based on Bayes' theorem. Both socioeconomic level and geographic origin of grandparents are given in a questionnaire devised by the first author. First, results obtained with the Bayesian dependent method (BD method) are compared to those obtained with a more commonly used method of dental age estimation based on Correspondence Analysis and linear Regression (CAR method). Second, two approaches are proposed in order to test potential relationships between socioeconomic level and stages of macroscopic dental development. Both are based on observed shifts between dental age and chronological age with regard to socioeconomic level. Results obtained with the BD method are better, in terms of quality, than those obtained with the CAR method. We observed no influence of socioeconomic level on stages of macroscopic dental development.

Non-adult dental age assessment: correspondence analysis and linear regression versus Bayesian predictions

This study focuses on the evaluation of factors influencing the quality (accuracy and reliability) of non-adult dental age assessment from radiographic stages of permanent teeth (excluding the third molar). We used four distinct cross-sectional samples of 1,528 healthy children: 3 of known geographic origin (Ivory Coast, Iran and France) and 1 additional sample of children whose grandparents originated from a different continent. Two different methods of calculations are compared: the correspondence analysis combined with linear regression (CAR) and Bayesian predictions (with no independence assumption). Our results indicate that the quality of age assessment does not seem to depend predominantly on the use of geographic-specific standards. In the case of Bayesian predictions, we observed a clear trend in favour of significantly higher accuracy and reliability levels when using non-geographic-specific standards. One of the main advantage of Bayesian predictions over maximum likelihood methods of estimation is an overall increase in accuracy with high levels of reliability on a fraction of the test sample and, importantly, across all age categories (contrary to methods based on regression analysis). Importantly, in the case of Bayesian non-adult predictions, and contrary to age estimation techniques based on regression, a better quality does not depend on age.