The Association of Developmental Dental Defects and the Clinical Consequences in the Primary Dentition: A Systematic Review of Observational Studies.

Purpose: Assess whether children with developmental defects of enamel (DDE) in primary teeth have a higher risk of having dental caries or a higher prevalence of clinical consequences due to the disease than those without DDE. Methods: Search was performed in PubMed, Scopus, Web of Science™, Cochrane Library, LILACS, BBO, Embase databases and in gray literature. Three independent reviewers were involved in study selection, data extraction, and bias assessment. Risk of bias was evaluated by the Newcastle-Ottawa scale. DDE and its subtypes (demarcated opacities, hypoplasia, hypomineralized second primary molars (HSPM), and fluorosis) were regarded as exposure. Dental caries and clinical consequences of untreated caries were also assessed. In the meta-analyses, odds ratio (OR) was used in the random effects model for dichotomous outcomes. Quality of evidence was assessed using the Grading Recommendations Assessment, Development and Evaluation (GRADE). Results: The search yielded 5,750 studies, 39 of which were included in the systematic review and 20 in the meta-analysis. The risk of bias ranged from 4 to 9 points. Children with DDE were more prone to primary tooth caries (OR=2.79; 95% CI:1.29-6.03), and so were those with demarcated opacities (OR=1.75; 95% CI:1.09-2.78), hypoplasia (OR=2.84; 95% CI:1.73-4.67), and HSPM (OR=2.89; 95% CI:1.65-5.06). Fluorosis was not associated with caries (OR=1.39; 95% CI:0.97-1.98). Regarding tooth as a unit of analysis, DDE was highly associated with caries (OR=2.34; 95% CI:1.74-3.16). As for the clinical consequences of caries, only the qualitative analysis was conducted and there was no consensus in the studies. Conclusion: DDE is associated with higher primary tooth caries experience.

Analyses of RAG1 and RAG2 genes suggest different evolutionary rates in the Cetacea lineage.

V(D)J recombination is a process of somatic recombination catalyzed by proteins encoded by RAG1 and RAG2 genes, both restricted to the genome of jawed vertebrates. Their proteins constitute the enzymatic core of V(D)J recombination machinery and are crucial for jawed vertebrate adaptive immunity. Mammals possess great ecological diversity, and their complex evolutionary history associated with radiation to different environments presented many distinct pathogenic challenges from these different habitats. Cetaceans comprise a mammalian order of fully aquatic mammals that have arisen from a complete terrestrial ancestor and, accordingly, was confronted with challenges from changing environmental pathogens while they transitioned from land to sea. In this study we undertook molecular evolutionary analyses of RAG1 and RAG2 genes, exploring the possible role of natural selection acting on these genes focusing on the cetacean lineage. We performed phylogenetic reconstructions on IQ-TREE, together with selection analyses in the codeml program of the PAML package, and in the FITMODEL program for codon evolution and switching on both the RAG1 and RAG2 genes. Our findings demonstrate that RAG1 and RAG2 remained fairly conserved among tetrapods, with purifying selection acting on both genes, with evidence for a few punctuated shifts in nucleotide substitution rates of both genes along tetrapod evolution. We demonstrate differential evolution in the closely linked genes RAG1 and RAG2 specifically in cetaceans.