ABSTRACT BACKGROUND: There is a lack of studies evaluating the oral health of traditional indigenous communities in Brazil. OBJECTIVES: Thus, the objective of this study was to describe the oral health characteristics of the indigenous Fulni-ô ethnic group in Northeast Brazil. DESIGN AND SETTING: A cross-sectional observational investigation was conducted within the Project on Atherosclerosis among Indigenous Populations. METHODS: This study included participants of both sexes from the Fulni-ô ethnic group. The participants included in this investigation underwent a comprehensive oral health evaluation by a registered and experienced dentist to assess oral health and identify potentially malignant oral lesions. Participants with suspicious lesions were referred for biopsy. Shapiro-Wilk, Mann-Whitney, and Student’s t-tests were used, and measures of central tendency and dispersion were described. Statistical significance was 5%. RESULTS: A total of 104 individuals were included in this study. The prevalence of the use of tobacco derivatives was 94.0%, with similarities between sexes. The prevalence of oral changes in this study population was 84.4%. Fifty-one individuals who underwent oral reassessment were referred for oral lesion biopsy. CONCLUSIONS: This study demonstrated a high prevalence of oral alterations in the Fulni-ô population. Histopathological analyses indicated the presence of mild oral epithelial dysplasia in five cases.

Several studies have shown that mutations and polymorphisms in clock genes are associated with abnormal circadian parameters in humans and also with more subtle non-pathological phenotypes like chronotypes. However, there have been conflicting results, and none of these studies analyzed the combined effects of more than one clock gene. Up to date, association studies in humans have focused on the analysis of only one clock gene per study. Since these genes encode proteins that physically interact with each other, combinations of polymorphisms in different clock genes could have a synergistic or an inhibitory effect upon circadian phenotypes. In the present study, we analyzed the combined effects of four polymorphisms in four clock genes (Per2, Per3, Clock and Bmal1) in people with extreme diurnal preferences (morning or evening). We found that a specific combination of polymorphisms in these genes is more frequent in people who have a morning preference for activity and there is a different combination in individuals with an evening preference for activity. Taken together, these results show that it is possible to detect clock gene interactions associated with human circadian phenotypes and bring an innovative idea of building a clock gene variation map that may be applied to human circadian biology.