The influence of implant position and of prosthetic characteristics on the occurrence of peri-implantitis: a retrospective study on periapical radiographs

Abstract Objective The present retrospective study aimed to investigate how implant position and the characteristics of the implant-supported prosthesis may influence the occurrence of peri-implantitis. Materials and methods The study included systemically healthy patients with single and partial implant-supported rehabilitations and at least 1-year post-loading follow-up. The parameters collected included implant-related factors, patient-related factors, site-related factors and prosthesis-related factors. The radiographic measurements were taken by using a dedicated software and the diagnosis of peri-implantitis was made based on all the available clinical and radiographic data. Descriptive statistics were provided for all variables. Following an exploratory approach, an implant-level analysis of factors influencing the occurrence of peri-implantitis was done through a multilevel multivariate logistic regression (mixed). Results A total of 180 implants belonging to 90 subjects were randomly selected. According to the multi-level analysis, the parameters that were significantly associated with peri-implantitis included presence / history of periodontitis (OR = 5.945, 95% CI: 1.093–32.334, P = 0.039) and presence of an emergence profile angle ≥ 45° (OR 9.094, 95% CI: 2.017–40.995, P = 0.005). Conclusions History of periodontitis and presence of a prosthetic emergence profile with an angle ≥ 45° were correlated to an increased risk of peri-implantitis. Conversely, we did not find a correlation between peri-implantitis and implant malposition.