Diederik Hentenaar

71 Erythritol air-polishing in non-surgical peri-implantits treatment None of the ultrasonic scaling studies in the current literature, evaluated the same piezoelectric ultrasonic scaler with plastic PEEK tip in the non-surgical treatment of peri-implantitis. Two studies with a comparative study design however were found evaluating subgingival instrumentation using an ultrasonic device (Vector® system) (Karring et al., 2005; Renvert et al., 2009). That ultrasonic device showed to be more effective in the reduction of BoP when compared to carbon fiber curettes and titanium curettes, respectively. However, no significant differences between the groups in clinical improvements (i.e., BOP, PPD, and bone level changes) were found. In accordance, our study showed a similar limited clinical effect of ultrasonic debridement. Therefore, from the data in the present study neither air-polishing nor ultrasonic cleaning could be considered a superior therapy in terms of our primary outcome (i.e., mean BoP at T3). Regarding the microbiological results in this study, comparable outcomes were found in two studies by Persson et al. 2010 and Persson et al. 2011. Both studies showed no difference in bacterial counts when using an air-polishing, ultrasonic scaling or laser therapy (Er:YAG), including no significant changes in bacterial load or in bacterial composition. Reduced bacterial counts of P. aeruginosa, S. aureus, and S. anaerobius were seen 1 month after the air-polishing therapy, but the bacterial counts did not decline further at the 6 month evaluation after air-polishing and laser therapy. As compared to these studies, the limited clinical effect observed in the present study seems to be underlined by the unchanged levels of periodontal pathogens. Success at 3 months after therapy was defined without BoP (%) being a discriminating factor. Rightly so, because if previously used success criteria would have been applied (e.g., criteria by Heitz Mayfield and Mombelli 2014, Carcuac et al. 2016), implants with PPD < 5 with concomitant BoP would be considered unsuccessful. According to the current treatment protocol patients subsequently would have been invited for a surgical follow- up. Looking at the gradual decline in clinical parameters (i.e., mean BoP, PPD ) within the successful group of implants, 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 this study 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. To decide which therapy could be considered preferable, next to the clinical, radiographical and microbiological parameters, treatment pain/discomfort of both therapies was assessed . In contrast to the periodontal literature, in which a low degree of discomfort for erythritol air-polishing was found compared to ultrasonic scaling, no difference in discomfort between both therapies in our study was found (Bühler et al. 2016). For both therapies an equal low level of pain was reported. Therefore 3