Abstract The aim of this study was to investigate the segregation patterns of molar incisor hypomineralization (MIH) in families, given the evidence that its etiology is influenced by genetics. Clinically, MIH may be detected in parents and/or siblings of MIH-affected children. Our study included children with at least one first permanent molar affected by MIH (proband) and their first-degree relatives (parents and siblings). The participants were examined clinically to detect MIH, according to the European Academy of Paediatric Dentistry criteria (2003). A total of 101 nuclear families (391 individuals) were studied. Proband diagnosis was followed by MIH classification of the subject, his parents and siblings, as affected, unaffected, or unknown. Segregation analysis was performed using the multivariate logistic regression model of the Statistical Analysis for Genetic Epidemiology package, and segregation models (general transmission, environmental, major gene, dominant, codominant and recessive models). The Akaike information criterion (AIC) was used to evaluate the most parsimonious model. In all, 130 affected individuals, 165 unaffected individuals, and 96 unknown individuals were studied. Severe MIH was found in 50.7% of the cases. A segregation analysis performed for MIH revealed the following different models: environmental and dominance (p = 0.05), major gene (p = 0.04), codominant (p = 0.15) and recessive models (p = 0.03). According to the AIC values, the codominant model was the most parsimonious (AIC = 308.36). Our results suggest that the codominant model could be the most likely for inheriting MIH. This result strengthens the evidence that genetic factors, such as multifactorial complex defect, influence MIH.
ABSTRACT Bone substitutes based on hydroxyapatite (HA) and Bonefill® (BO - inorganic bovine bone) associated with poly(lactic-co-glycolic acid) (PLGA) (HA/PLGA and BO/PLGA) were evaluated concerning cytotoxicity, genotoxicity and mutagenicity as potential candidates for bone repair. The materials were developed and provided by Bionnovation Biomedical Products Ltda. Eluates from these bone substitutes were prepared for toxicity evaluations using eukaryotic cell cultures. HA/PLGA was used as a comparison for Bonefill®. Cell viability was evaluated by XTT assay and surviving fraction was calculated for clonogenic survival. Additionally, tail moment was used to assess genotoxicity (comet assay). The frequencies of binucleated cells with micronucleus (FBMN), micronucleus (FMN), nucleoplasmic bridges (NPBs), and nuclear buds (NBUDs) were analysed by cytokinesis-block micronucleus assay (CBMN assay). Results showed no statistical difference in cell viability compared with negative control (NC) The eluates did not promote delayed cytotoxicity whereas the surviving fraction rate for cultured cells was similar to NC. Furthermore, no genotoxicity or mutagenicity effects were observed for cultured cells with the Bonefill/PLGA and HA/PLGA eluates. In conclusion, the negative cytotoxicity, genotoxicity and mutagenicity results indicate that these bone substitutes presented interesting preliminary results as potential biomaterials for bone repair.
Abstract The objective of this study was to investigate the association between single nucleotide polymorphisms (SNPs) in the IL10, NOS2A, and ESR2 genes and chronic periodontitis (CP) and aggressive periodontitis (AgP). Three groups of patients underwent periodontal and radiographic evaluations: CP (n = 61), AgP (n = 50), and periodontally healthy (control group=61). Genomic DNA was extracted from oral epithelial cells and used for genotyping by real-time polymerase chain reaction using TaqMan® probes. The investigated SNPs were: -1087G > A, -819C > T and -592C > A in the IL10; +2087G > A in the NOS2A, and +1730G > A in the ESR2 gene. Differences in genotype and allele frequencies of each polymorphism and some individual characteristics were analyzed using the chi-square test and multivariate logistic regression analysis. Analysis of SNPs and haplotypes in the IL10 and SNP in the ESR2 gene did not present any significant association with AgP or CP. The +2087G allele of the NOS2A gene tended to be significantly associated with periodontal disease. Patients carrying the genotype +2087GG in the NOS2A gene were genetically protected against the development of CP (p = 0.05; OR = 0.44; 95%CI = 0.20–0.95). This result showed greater significance when patients with AgP and CP were combined (total PD) (p = 0.03; OR = 0.46; 95%CI = 0.23–0.92). In conclusion, the studied Brazilian population had a significantly higher frequency of the GG genotype for the +2087 SNP in the NOS2A gene in individuals without periodontitis, although statistical significance was not maintained after multiple logistic regression.
INTRODUCTION: Dentinogenesis imperfecta (DI) is a hereditary dentin development disorder that affects both primary and permanent dentitions. The DI characteristics are discolored and translucent teeth ranging from gray to brownish-blue or amber. The enamel may split readily from the dentin when subjected to occlusal stress. Radiographically there are evident of cervical constrictions, short root and pulp chambers, and the root canals are smaller than normal or completely obliterated. The dental treatment choice can be decided on a case-by case‑basis, considering the degree of dental tissue loss, and child age and cooperation. OBJECTIVE: The aim of this case report was to describe the early dental treatment performed in a child affected by DI type II. CASE REPORT: The treatment involved basic preventive procedures. Primary molars were worn to such an extent that the remained tooth structure was covered with composite resin to protect the exposed dentin. Resin-based sealant was applied in all first permanent molars. Posterior cross bite was treated with the expansion of the upper arch. CONCLUSION: The early treatment restored the patient´s vertical dimension resulting in acceptable esthetics and function for the permanent teeth to complete their eruption.
INTRODUÇÃO: A dentinogênese imperfeita (DI) é uma desordem hereditária no desenvolvimento da dentina, que afeta tanto a dentição decídua quanto a permanente. A DI apresenta como características dentes escurecidos e translúcidos que vão do cinza ao marrom ou âmbar. O esmalte pode se separar facilmente da dentina quando submetido ao estresse oclusal. Radiograficamente há evidencias de constrição cervical, raiz curta e polpas reduzidas, sendo os canais menores do que o comum ou completamente obliterados. A escolha do tratamento pode ser decidida com base no caso, considerando-se a idade da criança, grau de perda de tecido dentário e de cooperação do paciente. OBJETIVO: O objetivo deste relato de caso foi descrever o tratamento odontológico precoce realizado em uma criança afetada pela DI tipo II. RELATO DO CASO: O tratamento envolveu procedimentos básicos de prevenção. Molares decíduos foram desgastados, de tal forma que a estrutura remanescente do dente foi coberta com resina composta para proteger a dentina exposta. Selante resinoso foi aplicado em todos os primeiros molares permanentes. Mordida cruzada posterior foi tratada com a expansão do arco superior. CONCLUSÃO: O tratamento precoce restaurou a dimensão vertical do paciente resultando em estética e função aceitáveis para os dentes permanentes completarem sua erupção.