The effect of interleukin-1 allele 2 genotype (IL-1a(-889) and IL-1b(+3954)) on the individual's susceptibility to peri-implantitis: case-control study.

Individuals bearing the combination of interleukin (IL)-1 allele 2 at IL-1A(-889) and IL-1B(+3954) are referred to as being genotype positive and are susceptible to increased periodontal tissue destruction. The aim of this study was to assess the possible association of IL-1 allele 2 (IL-1A(-889) and IL-B(+3954)) genotypes with the severity of peri-implantitis progression and the effect of this combination on treatment outcomes. Fifty patients with International Team for Implantology implants were studied; patients ranged in age from 35-55 years, and each patient had 1 implant. According to peri-implant tissue status, patients were divided into 2 groups: group I consisted of 25 patients with peri-implantitis, and group II comprised 25 patients with healthy peri-implant tissue. Clinical parameters were assessed at baseline and after 3 and 6 months. Epithelial cells were collected from the oral mucosa by plastic spatula and were used for IL-1 genotyping by the polymerase chain reaction technique. Group I patients were subjected to a peri-implantitis treatment and maintenance program. In all, 17 patients from group I and 5 patients from group II were genotype positive, with a statistically significant difference noted between the 2 groups. Group I genotype-positive patients presented with higher scores and measurements of clinical parameters with increased suppuration from peri-implant tissues compared with group II; differences were statistically significant (P < .05). In terms of response to treatment, genotype-negative patients demonstrated better response than genotype-positive patients. The combination of IL-1 allele 2 (IL-1A(-889) and IL-1B(+3954)) in patients with inflamed periodontal or peri-implant tissues acts as a risk factor that leads to greater tissue destruction. IL-1 gene polymorphism at IL-1A(-889) and IL-1B(+3954) may affect outcomes of treatment for peri-implantitis in genotype-positive individuals.