BACKGROUND: The aim of this study was to investigate the association between T950C (rs2073617) and G1181C (rs2073618) polymorphisms of the osteoprotegerin gene (OPG) and the susceptibility of peri-implantitis in the Chinese Han population. 

MATERIAL AND METHODS: 110 patients with peri-implantitis and 116 healthy persons from the Chinese Han population were included in this study using a case-control design; rs2073617 and rs2073618 in OPG were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The linkage disequilibrium (LD) and haplotype analysis were performed with Haploview software. Hardy-Weinberg equilibrium (HWE) was assessed in the control group based on the genotype distributions of OPG polymorphisms. The genotype, allele, and haplotype distribution differences between the case and control groups were analyzed by chi-square test, and the relative risk of PD was expressed by odds ratio (OR) and 95% confidence interval (CI). 

RESULTS: The study results showed that people carrying the CC genotype of rs2073618 were more likely to have peri-implantitis than GG genotype carriers (OR=2.18, 95% CI=1.03–4.62, p=0.04). In addition, patients with the C allele had 1.47 times the risk of suffering from peri-implantitis (OR=1.47, 95% CI=1.01–2.13, p=0.04), but not rs2073617 polymorphism. The G-C haplotype frequency of rs2073618-rs2073617 in OPG was significantly correlated to the increased susceptibility of peri-implantitis (OR=2.27, 95% CI=1.20–4.30). 

CONCLUSIONS: OPG rs2073618 polymorphism may be related to the risk of peri-implantitis, but not rs2073617. Moreover, haplotype is also a non-ignorable risk factor. 

Keywords: Case-Control Studies, Alleles, Ethnic Groups - genetics, Gene Frequency, Genetic Predisposition to Disease, Haplotypes, Linkage Disequilibrium, Osteoprotegerin - metabolism, Peri-Implantitis - metabolism, Polymorphism, Single Nucleotide