Association of Cytokine Gene Polymorphism with Peri-implantitis Risk

Purpose: To investigate whether polymorphisms of cluster of differentiation 14 (CD14), tumor necrosis factor alpha (TNFα), interleukin (IL)6, IL10, and IL1ra genes are associated with the risk of peri-implantitis susceptibility in patients with dental implants in the Serbian population. Materials and Methods: Isolated DNA from the blood was used for IL10-1082, TNFα-308, IL6-174, CD14-159, and interleukin 1 receptor antagonist (IL1ra) genotyping using polymerase chain reaction (PCR)-based methodology. Clinical parameters included: peri-implant pocket depth (PPD), Plaque Index (PI), Gingival Index (GI), bleeding on probing (BOP), and radiologic bone loss. Results: The study included 98 patients with dental implants in function for at least 1 year, divided into peri-implantitis (34) and healthy peri-implant tissue (64) groups. The percentage distribution of smokers was significantly different between patients who developed periimplantitis and patients with healthy peri-implant tissue (71% vs 42%, respectively) and associated with increased peri-implantitis risk (OR: 3.289, 95% CI: 1.352 to 8.001; P = .007). A positive history of periodontitis was more frequent in the peri-implantitis group (62%) than in the healthy peri-implant tissue (20%) group and associated with increased peri-implantitis risk (OR: 6.337, 95% CI: 2.522 to 15.927; P = .0001). Frequencies of CD14-159, TNFα-308, IL10-1082, and IL6-174 genotypes were significantly different between patients with and without peri-implantitis. However, logistic regression revealed only TNFα-308 polymorphic GA/AA genotypes (OR: 8.890, 95% CI: 2.15 to 36.7; P = .003) and smoking (OR: 6.2, 95% CI: 1.44 to 26.7; P = .014) as independent factors associated with increased peri-implantitis risk, while CD14-159 polymorphic CT/ TT genotypes were associated with decreased risk for peri-implantitis (OR: 0.059, 95% CI: 0.009 to 0.355; P = .002). Conclusion: The findings suggest that smoking and the presence of TNFα-308 GA/AA genotypes may increase the risk for peri-implantitis, while CD14-159 polymorphic CT/TT genotypes decrease the risk. The results also indicate significant association of CD14-159, TNFα-308, and IL6-174 genotypes and clinical parameters in the Serbian population. However, future studies in larger patient groups are necessary to confirm these observations. Keywords: cytokines, genetic polymorphism, inflammation, peri-implantitis