Diederik Hentenaar

173 Summary considered succesfull at 3 month follow-up, parameters were additionally assessed at 6, 9 and 12 months. Moreover, evaluation of patient percepted pain scores took place directly after intervention using a VAS-scale. A total of eighty patients having 139 implants with peri-implantitis were non-surgically treated. Patients were randomly assigned to the test group or control group. In both groups, a single session of full mouth periodontal cleaning was performed and the peri-implant area was treated with either eryhtritol air-polishing treatment or piezo-electric ultrasonic therapy with PEEK plastic tip. Three months post therapy no significant difference between both therapies for the primary outcome mean bleeding on probing (%) (BoP) was found. Moreover, other clinical parameters, including suppuration on probing (SoP), levels of plaque (Plq) and probinig pocket depth (PPD), marginal bone levels or microbiological parameters showed any difference between both groups. Both therapies resulted in limited success i.e. 18% of the patients was considered succesfull. Evaluation of patient percepted pain scores directly after intervention indicated that both therapies were considered minimally painful without one of both being significantly less painful. Therefore, it was concluded that air-polishing seemed to be as effective as ultrasonic scaling in the reduction of inflammatory signs without being perceived more or less painfull (BoP, SoP, Plq and PPD). Hence, neither erythritol air-polishing nor ultrasonic cleaning could be considered a superior therapy in terms of our primary outcome i.e., mean BoP at T3. When baseline characteristics of the successful group of patients were compared with the unsuccessful ones, lower PPD (4.0mm vs 4.9mm, respectively), less marginal bone loss (3.0mm versus 4.0mm, respectively) and shorter time in function before therapy took place (7.2 versus 9.5 year) were seen. Interestingly, follow-up of the successful patients showed gradual improvement of peri-implant parameters up to 12 months when supportive peri-implant therapy (supragingival instrumentation when plaque/calculus was visible) and oral self-care re-inforcement were applied at 6 and 9 months. Hence, considering the success of these patients up to 12 months after therapy, these parameters indicate the importance of early diagnosis and early commencement of non-surgical therapy. Moreover, it seemed that stable bone levels and absence of progression of disease could be attained in implants showing PPD < 4mm with the presence of BoP up to 12 months. Therefore the outome of chapter 3 underlines that the sensitivity of BoP for the prediction of disease progression is quite low and that strict success criteria need to be cautiously interpreted and applied. In chapter 4 we aimed to evaluate the effect of mechanical implant surface decontamination using an air polisher with erythritol powder on clinical, radiographical and microbiological parameters. The parameters were assessed before treatment (baseline), 3,6,9 and 12 months follow-up. Patients which were considered unsuccessful at 3 month follow-up in the non-surgical peri-implantitis study of chapter 3 were A