Gene-environment interaction in molar-incisor hypomineralization.

Molar incisor hypomineralization (MIH) is an enamel condition characterized by lesions ranging in color from white to brown which present rapid caries progression, and mainly affects permanent first molars and incisors. These enamel defects usually occur when there are disturbances during the mineralization or maturation stage of amelogenesis. Both genetic and environmental factors have been suggested to play roles in MIH's development, but no conclusive risk factors have shown the source of the disease. During head and neck development, the interferon regulatory factor 6 (IRF6) gene is involved in the structure formation of the oral and maxillofacial regions, and the transforming growth factor alpha (TGFA) is an essential cell regulator, acting during proliferation, differentiation, migration and apoptosis. In this present study, it was hypothesized that these genes interact and contribute to predisposition of MIH. Environmental factors affecting children that were 3 years of age or older were also hypothesized to play a role in the disease etiology. Those factors included respiratory issues, malnutrition, food intolerance, infection of any sort and medication intake. A total of 1,065 salivary samples from four different cohorts were obtained, and DNA was extracted from each sample and genotyped for nine different single nucleotide polymorphisms. Association tests and logistic regression implemented in PLINK were used for analyses. A potential interaction between TGFA rs930655 with all markers tested in the cohort from Turkey was identified. These interactions were not identified in the remaining cohorts. Associations (p<0.05) between the use of medication after three years of age and MIH were also found, suggesting that conditions acquired at the age children start to socialize might contribute to the development of MIH.

Dental caries: Genetic and protein interactions.

OBJECTIVE: To present a genetic and protein interaction analysis associated with dental caries. MATERIAL AND METHODS: The first step was to conduct a systematic literature review (SLR) through an electronic database search. Case-controls that reported associations between genes and dental caries were the main type of study design used as inclusion criteria, retrieved from the PubMed and the Virtual Health Library databases, comprising the chronological range from 1982 to 2017. The SLR was guided by PRISMA protocol and the methodological quality of the studies was established through Newcastle-Ottawa Scale (NOS). In the second step, the String Protein Interaction (SPI) approach was used to analyze protein interaction (by esyN software) and also the Ingenuity Pathway Analysis (IPA) to check biological pathways associated with dental caries genes. RESULTS: A total of 51 articles were included to perform this SLR, describing a number of 27 genes associated with dental caries development. At the genetic level, 23 genes have at least one other gene with which they interact. The genes TUFT1, VDR, TFIP11, LTF, HLA-DRB1, MMP2, MMP3 and MUC5B were shown to be connected in interactive networks by at least 10 other genes. CONCLUSION: It is essential to apprehend the multifactorial pattern of inheritance in human disease. This study presents pathways which may be directly correlated with several dental caries phenotype and this contributes to a better understanding of this disease, opening up a wider range of biotechnology options for its effective control in the future.

KLK4 Gene and Dental Decay: Replication in a South Brazilian Population.

OBJECTIVE: The objective of this research was to identify and replicate the participation of KLK4 gene polymorphisms in the susceptibility to dental decay. METHODS: A total of 200 patients were recruited using ICDAS criteria - 100 of them with dental caries and 100 with no history of the disease. Buccal cells were collected and the DNA was extracted and amplified using PCR. RESULTS: During the descriptive analysis, the variables ethnicity, biofilm, and gingivitis and the markers rs2242670 and rs2978642 were statistically significant. In the multivariate analysis, the marker rs2242670 and the variable biofilm maintained statistical significance. CONCLUSION: Genetic variations in the KLK4 gene may contribute to dental decay.

Assessment of the quantity and purity of DNA obtained from buccal cells under different storage methods / Avaliação da quantidade e pureza do DNA obtido por meio de raspagem de células da mucosa buccal sob diferentes condições de armazenamento

Aim: This study aimed to verify the quantity and purity of DNA obtained from buccal cells under different storage conditions. Methods: Thirty students, between 18 and 23 years of age participated in the study. Three samples of genetic material were collected from each student (samples A, B, and C) through a mouth rinse with 5 mL of 3% glucose. The first phase of DNA extraction from sample A was carried out on the same day of sample collection, whereas samples B and C were stored in a refrigerator and a freezer, respectively, for 1 month before the first extraction phase. DNA extraction was performed with 10 M ammonium acetate and 1 mM EDTA. Sample purity was assessed by spectrophotometry. Statistical analyses were performed through descriptive analysis and analysis of variance ANOVA using the SPSS software, version 21.0. Results: the samples presented no statistically significant differences between the DNA quantity (p = 0.37) or quality (p = 0.16). Conclusion: the quantity and purity of DNA extraction from the three samples were satisfactory, and no differences in storage conditions were found.(AU)

Objetivo: O objetivo desta pesquisa foi avaliar a quantidade e pureza do DNA obtido por células bucais utilizando diferentes meios de armazenagem. Métodos: trinta estudantes do curso de Odontologia entre 18 e 23 anos participaram desta pesquisa. O material genético foi coletado 3 vezes de cada indivíduo (amostras A B e C) por meio de bochechos com 5 ml de glicose 3%. Para a amostra A, foi realizada a primeira fase da extração do DNA no dia da coleta, já as amostras B e C, ficaram armazenadas em geladeira e freezer, respectivamente, por um mês antes da primeira extração. A extração do DNA foi realizada com acetato de amônio 10M e EDTA 1mM. Avaliouse a pureza das amostras por espectrofotometria. Resultados: as amostras não apresentaram diferenças estatisticamente significativas entre a quantidade (p = 0,37) ou pureza (p = 0,16) do DNA. Conclusão: a quantidade e a pureza do DNA das três amostras foram satisfatórias e não houve diferenças nas condições de armazenamento.(AU)