Association of Locus Xq26.1-27.3 with Erosive Tooth Wear Phenotypes in a Group of Adolescents.

Erosive tooth wear is a multifactorial condition of an increasing prevalence. There is a need for discovering individual genetic predisposition for the development of this condition. Considering that the chromosome X locus was previously shown to be associated with dental caries, the aim of the present study was to look for the association between this locus and erosive tooth wear when dietary habits are considered as a co-factor. Saliva samples, erosive wear experience data, and dietary information from 16- to 18-year-old dental patients (n = 705) were used. Genotyping analyses were performed, and thereafter, analyses considering diet and oral hygiene data, using logistic regression, with the assumption that erosive tooth wear is a complex gene-environment model. Genotypic analyses revealed an association between chromosome X marker rs1324156 and erosive tooth wear phenotype. Logistic regression analysis showed that, in the presence of less common allele of rs12687601 and rs1324156, erosive tooth wear more likely develops when associated with numerous dietary variables from the questionnaire. These results indicate that erosive tooth wear may be the result of gene-environment interactions.

Genes and Dietary Preferences and Their Impact on Caries Susceptibility and Erosive Tooth Wear.

A dietary pattern rich in refined sugars is associated with higher caries experience. However, people show differences in references for certain foods, and these differences are genetic in origin. In this chapter, dietary preference is the focus of the discussion of individual susceptibility to dental caries and erosive tooth wear.

Comparisons of tooth sizes, dental arch dimensions, tooth wear, and dental crowding in Amazonian indigenous people.

INRODUCTION: Our objective was to assess tooth wear, arch dimensions, tooth sizes, and dental crowding in 4 remote indigenous villages on the Xingu River in Brazil. These populations have similar patterns of dietary habits and practice exclusive breast-feeding, whereas studies in human genetics show large intertribal genetic distances and low intratribal variations. METHODS: Dental casts of 107 subjects in the permanent dentition were evaluated. Tooth wear, arch dimensions, mesiodistal tooth widths, and the irregularity index of the incisors were obtained and compared using analysis of variance or the Kruskal-Wallis test (P <0.05). RESULTS: Tooth wear and tooth size in the mandible were similar among villages. Three groups were discriminated. The first group included the Xicrin-Kayapó and Arara-Laranjal villages, since no significant difference was found between them. Larger tooth sizes and arch dimensions (P <0.001) were found in both jaws in the Assurini village compared with the Xicrin-Kayapó and Arara-Laranjal villages; this resulted in similar dental crowding index values in these groups. The Arara-Iriri village, where a high coefficient of inbreeding had been reported, showed intermediate arch dimensions, with the mesiodistal tooth widths similar to those in the Xicrin-Kayapó and Arara-Laranjal villages. This scenario resulted in a group with the lowest irregularity index, close to 0. CONCLUSIONS: These Amazonian indigenous villagers, who have been genetically studied previously, showed large intergroup genetic variations and similar patterns of tooth wear. Thus, we suggest from the findings in this study that the etiology of dental crowding among the inhabitants of the Xingu River area is predominantly associated with variations in the dimensions of dental arches, related to genetic influences.

Morfologia dentofacial e características oclusais dos índios Arara: revisitando o papel da hereditariedade e da dieta na etiologia da má oclusão / Dentofacial morphology and occlusal characteristics of Arara indigenous: revisiting the role of heredity and diet in the etiology of malocclusion

A influência da dieta e da hereditariedade nas características dentofaciais foi avaliada através do exame de duas populações indígenas amazônicas divididas por um processo de fissão linear. Os indígenas que constituem a aldeia Arara-Iriri são descendentes de um único casal expulso da aldeia Arara-Laranjal. O crescimento da aldeia Iriri ocorreu pelo acasalamento de parentes próximos, ratificado por um alto coeficiente de consanguinidade (F=0,25, p<0,001). A epidemiologia da má oclusão e das características da face foi analisada nos indivíduos entre dois e 22 anos, das aldeias Iriri (n=46) e Laranjal (n=130). A biometria da dentição e da face foi obtida em 55 indígenas em dentição permanente sem perdas dentárias, através da fotogrametria facial e dos modelos de gesso. O desgaste dentário foi examinado em 126 indivíduos através da análise de regressão múltipla. Os resultados revelaram uma determinação significativa da idade no desgaste dos dentes (R2=87,6, p<0,0001), que se mostrou semelhante entre as aldeias (R2=0,027, p=0,0935). Por outro lado, diferenças marcantes foram observadas nas características dentofaciais. Revelou-se uma face mais vertical (dolicofacial) entre os índios Iriri e o predomínio do tipo braquifacial nos indígenas da aldeia original, corroborado pela fotogrametria. Uma face sagitalmente normal foi observada em 97,7% da aldeia Laranjal, enquanto faces convexas (26,1%, RR-16,96) e côncavas (15,2%, RR=19,78) eram mais prevalentes na aldeia Iriri (p<0,001). A biprotrusão, com consequente redução do ângulo nasolabial, era uma característica comum entre os Arara, porém com maior prevalência no grupo Iriri (RP=1,52, p=0,0002). A prevalência da má oclusão foi significativamente mais alta na aldeia Iriri (RP= 1,75, p=0,0007). A maioria da população da aldeia original (83,8%) apresentou uma relação normal entre os arcos dentários, contudo, na aldeia resultante (Iriri), 34,6% dos indivíduos era Classe III (RP=6,01, p<0,001) e 21,7% era Classe...

The influence of diet and genetics on dentofacial features was examined through the analysis of two split indigenous Amazon populations originated by a process of a linear fission. The Arara-Iriri indigenous are descendants of a single couple who were expelled from a larger village (Arara-Laranjal). In the resultant new village, the initial expansion occurred through the mating of closely related people, causing a high coefficient of inbreeding (F=0.25, p<0.001). The epidemiology of malocclusion and facial characteristics were analyzed in individuals aged from 2 to 22 years, from the Arara-Iriri (n=46) and Arara-Laranjal (n=130) villages. The biometric study of the dentition and face was performed in the permanent dentition of the indigenous without tooth loss (n=55) by facial photogrammetry and dental casts analysis. Tooth wear was examined in 126 individuals in the permanent dentition through multiple regression analysis. Findings pointed out a significant determination of age on tooth wear (R2=87.6, p<0.0001), which was similar between the villages (R2=0.027, p=0.0935). However, we found marked differences in the dentofacial morphology. The indigenous of the Iriri village presented a more vertical face (dolichofacial) compared to the people of the original village, predominantly braquifacial. This clinical data was corroborated by facial photogrammetry. A sagitally normal face was observed in 97.7% of the Laranjal village, while convex (26.1%, RR=16.96) and concave faces (15.2%, RR=19.78) were significantly more prevalent in the Iriri village (p<0.001). Biprotrusion, with consequent reduction of nasolabial angle, was a common feature among the Arara indigenous, but its occurrence in the Iriri village was higher (RP=1.52, p=0.0002). The prevalence of malocclusion was significantly higher in the Iriri population (RP=1.75, p=0.0007). While the majority of the population (83.8%) in the Laranjal village presented a normal ...(AU)