Single Nucleotide Polymorphisms of Salivary Human Beta Defensins 1 in Relation to Dental Caries

Background: The role of genetics in determining an individual’s susceptibility to caries is significant, with the human Beta-Defensin 1 gene ( DEFB1 ), responsible for encoding the human β -defensin 1 (hBD1) antimicrobial peptide, being a potential candidate for studying genetic susceptibility to caries due to its constitutive expression. Genetic variations in DEFB1 have been associated with impaired production of hBD1, increasing the vulnerability to oral pathogen infections and potentially leading to dental caries. Objectives: As hBD1 localizes in the oral cavity, the objective of the study is to investigative level of salivary Beta defensins 1 and genetic variation that could contribute to caries susceptibility among adolescents in Baghdad city. Materials and Methods: A case–control study was conducted among 78 ad olescents (39 very low caries and 39 high caries) aged 13–15 years old in Baghdad city. Three single nucleotide polymorphisms (SNPs) were identified from unstimulated saliva samples, namely rs1799946, rs5743418, and rs11362. Saliva collection was done, and then dental caries was evaluated with the D1-4MFS/D1-4MFT (decayed, missing, filled surface/teeth) index. Results: There were high concentrations of salivary B-Defensin 1 in control group (very low caries group) compared to study group (high caries group) with significant difference ( P = 0.038). It also showed that no significant difference was found between the study and the control groups in genotype distribution except for SNP (rs5743418) there was significant difference in heterozygous genotype (CT) and no significant deviation from Hardy-Weinberg equilibrium in genotype distribution of both groups. DEFB1 SNPs were significantly associated with the caries experience: the strongest association emerged from rs5743418 SNP ( P = 0.006). Conclusions: The rs5743418 SNPs of DEFB1 gene and its level in saliva had a relation with caries experience suggesting that these could be considered as potential marker for assessing the risk for developing caries.