Diederik Hentenaar

172 Addendum SUMMARY The gold standard for treatment of peri-implantitis remains to be found. The aim of the research presented in this thesis was to perform randomized clinical trials to clinically, radiographically, microbiologically and immunologically evaluate the influence of a single implant surface decontaminating/peri-implant debridement intervention. In addition, the aim was to add knowledge on the peri-implant diagnosis and on the influence of the implant supported crown contour with regard to the peri-implant condition. The aim of the study presented in chapter 2 was two-fold: first, to compare biomarker levels in peri-implant crevicular fluid (PICF) of implants with a peri-implant healthy status with levels in PICF of implants with peri-implantitis and second to compare biomarker levels before and after non-surgical treatment. In total, periopaper samples were taken from 20 healthy implants in 17 patients and from 20 implants with peri- implantitis in 19 patients, before and 3 months after non-surgical treatment using the Airflow Master Piezon ® (EMS). For test group samples, patients from the study in presented in chapter 3 were asked to additionally participate in the study described in chapter 2 . A Luminex™ assay was used to evaluate pro-inflammatory and anti- inflammatory cytokines IL-1β, TNF-α, IL-6 & G-CSF, collagen degradation enzyme MMP-8, chemokines MCP-1 & MIP-1α/CCL3, bone markers OPG & sRANKL and interferon-γ. Clinical and radiographical characteristics were assessed at baseline and at 3 months. Results showed significantly elevated levels of IL-1β and MMP-8 levels in implants with peri-implantitis when compared to implants with a healthy status ( p = .007; p=< .001, respectively). No difference in other biomaker levels (i.e., TNF-α, IL-6, MCP-1 and MIP-1α/ CCL3, OPG & G-CSF) between healthy and diseased implants were found. Levels of sRANKL and INF-γ were under the level of detection. Evaluation of biomarker levels 3 months after non-surgical therapy did not significantly improve, levels of IL-1β and MMP-8 remained high. Hence, it was concluded that Implants diagnosed with peri- implantitis have higher levels of IL-1β and MMP-8 in PICF compared to healthy implants and non-surgical therapy did not seem to influence the inflammatory immune response. In chapter 3 and 4 two randomized controlled trials are presented which together describe a two-staged peri-implantitis treatment protocol evaluating the effect of mechanical debridement using an air-polisher in a non-surgical study ( chapter 3 ) and a resective surgical approach ( chapter 4 ). The aim in the study described in chapter 3 was to evaluate the effect of a single non-surgical intervention using air-polishing with erythritol powder (test group) and compare the effect with piezo-electric ultrasonic cleaning (control group) on clinical, radiographical and microbiological parameters. Patients were assessed at baseline and 3 months follow-up. In patients which were