| Abstract [eng] |
Relevance: Dental caries is a disease of complex etiology, the development of which is promoted by many risk factors. Genetic factors, such as the copy number of the salivary α-amylase 1 (AMY1) genes, often remain unassessed. Data that we have collected during this study has high likelihood to contribute significantly to developing personalized dentistry strategies. Aim: To evaluate the associations between dental caries and copy number variation of the salivary α-amylase 1 (AMY1) locus genes in individuals with intellectual disabilities. Objectives: To assess sociodemographic characteristics and oral health care–related behaviors; to determine dental caries indices and their distribution by sex and age; to determine the copy number of AMY1 locus genes; to evaluate the associations between copy number of AMY1 genes and dental caries, adjusting for sociodemographic characteristics and oral health care–related behaviors. Material and methods: The study was conducted with the permission from the Vilnius Regional Biomedical Research Ethics Committee and informed consents. In this cross-sectional study using convenience sampling we analyzed data from 63 adult individuals with intellectual disabilities who received oral disease treatment under general anesthesia at the Žalgiris Clinic. Based on the 2013 WHO recommendations, calibrated clinician assessed the subjects' dental caries indexes and took a buccal mucosal swabs. The guardians of the subjects were asked to complete the WHO questionnaires, which assessed oral health care-related behaviors and sociodemographic characteristics. Genetic analysis was conducted at the Institute of Biosciences, VU LSC. DNA purification was performed using the MagMAX (Thermo Fisher Scientific, USA) nucleic acid isolation kit and the automated KingFisher Flex™ (Thermo Fisher Scientific) DNA purification system. The analysis of AMY1 genes copy number was performed using real-time PCR methodology based on the hydrolysis probe method, using the QuantStudio Pro™ 7 real-time PCR system (Thermo Fisher Scientific). Data processing and statistical analysis were conducted using Microsoft Excel (Microsoft 365, Microsoft, USA) and IBM SPSS (IBM, USA) software. Results: The mean age (SD) of 63 subjects with intellectual disabilities (44 % (N = 28) were women) aged 19-54 years was 30,9 (7.9) years. Out of the 57 subjects’ guardians who responded to the questionnaire on place of residence, 75 % (N = 43) reported living in an urban area. The mean (SD) values of dental caries indices were determined: DMFS – 38,8 (26,3), DMFS of smooth tooth surfaces – 13,6 (11,8) and DMFT – 14,3 (5,7). The mean (SD) copy number of AMY1 locus genes was 6,8 (3,1). A negative correlation was found between the copy number of AMY1 locus genes and the DMFT index (ρ = -0,272, p = 0,031). The relationships between dental caries and copy number of AMY1 genes were evident in the female group, where negative correlations were obtained between the copy number of AMY1 genes and the DMFT index (ρ = -0,552, p = 0,002) and between the copy number of AMY1 genes and the DMFS index of smooth tooth surfaces (ρ = -0,439, p = 0,020). Negative correlations between the copy number of AMY1 genes and dental caries were also observed in the group of subjects living in cities (ρ = -0,331, p = 0,030) or villages (ρ = -0,735, p = 0,024), and in the group of subjects whose caregivers did not brush their teeth the day before visiting a dental clinic (ρ = -0,670, p = 0,049). Conclusions: Lower AMY1 locus genes copy number was associated with greater dental caries experience among adults with intellectual disabilities, particularly among females, individuals living in urban and rural areas, and participants whose caregivers did not brush their teeth the day prior to the dental visit. Further large-scale studies are needed to confirm the associations between the copy number variation of AMY1 locus genes and dental caries. |
