Prognostic indicators for surgical peri-implantitis treatment

Objectives: Objective of this study was to identify prognostic indicators for the outcome of resective peri-implantitis treatment, by an analysis of the pooled data of two previously conducted randomized controlled trials. Material and methods: Data of 74 patients with peri-implantitis (187 implants) who had received resective surgical treatment were available. Primary outcome variable was failure of peri-implantitis treatment after 12 months. Multilevel univariable and multiple logistic regression analyses were performed to evaluate the effect of various potentially prognostic indicators on the primary outcome. Results: Peri-implantitis treatment was unsuccessful in 106 implants (57%) and 48 patients (67%) after 12 months. In the multiple regression analysis, the variables "order of inclusion" (P = 0.016) and mean bone loss at baseline (P = 0.030) were significant prognostic indicators for treatment failure. To eliminate the effect of " order of inclusion," post hoc analyses were carried out in a subgroup of patients. The univariable post hoc analysis showed a significant association for smoking (P = 0.015), maximum pocket depth at baseline (P = 0.073), mean bone loss at baseline (P = 0.003), and presence of plaque (P = 0.100). In the multiple regression post hoc analysis, only the variables smoking (P = 0.044) and mean bone loss (P = 0.043) remained statistically significant. Conclusions: The outcome of surgical peri-implantitis treatment is influenced by the experience of the surgical team with the surgical procedure. The observed learning effect has consequences for clinical practice and for conducting and interpreting clinical trials on peri-implantitis treatment. Other prognostic indicators are amount of peri-implant bone loss at baseline and smoking, and to a lesser extent, probing pocket depth at baseline and presence of plaque during follow-up. Early diagnosis of peri-implantitis and control of behavioral factors are crucial in achieving periimplantitis treatment success.