Diederik Hentenaar

70 Chapter 3 follow-up. Interestingly, follow-up of 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. In addition, both therapies were considered minimally painful without one of both being significantly less painful. Comparison with relevant findings from other published studies To date, no studies have evaluated erythritol air-polishing as monotherapy for the non-surgical treatment of peri-implantitis. Only two previous studies report on a single non-surgical intervention in peri-implantitis patients with glycine air-polishing therapy ( John et al. 2015; Renvert et al. 2011). When glycine powder air-polishing was compared with mechanical debridement + local antiseptic therapy using chlorhexidine in a study by John and coworkers, a significant higher reduction in mean BoP scores at 3 months was found (BoP reduced from 99.0% ±4.1 to 57.8%±30.7 in the air-polishing group and from 94.7%±13.7 to 78.1%±30.0 in the mechanical debridement group). Compared to the present study, glycine air-polishing also seemed to result in a greater reduction of BoP. However, the study by John et al. included patients with as initial or moderate forms of peri-implantitis (probing pocket depths of ≥4mm compared to ≥5mm in our study and the loss of supporting bone as ≤ 30% compared to ≥ 2mm in our study), implying that implants with a less severe state of inflammation might have been studied. In addition, only non-smoking patients were included and a high risk of bias on several items was reported (e.g., allocation concealment, blinding of participants and selective reporting) in the recent systematic review (Suárez-López Del Amo et al. 2016). Therefore, interpreting these results should be done cautiously. In comparison with Renvert et al., no statistical differences in clinical parameters (BoP, SoP, Plq and PPD) and bone level changes were found when glycine air-polishing (Perioflow®) was compared to laser therapy (Er:YAG). Also, the range of pocket depth reduction in the present study was comparable to the reductions in the study by Renvert et al. (between 0.1mm and 1mm at 6-months in the majority of patients). Moreover, comparable changes in average marginal bone loss were found for air-polishing (0.1mm (±0.8)) at 3 months. This despite the fact that suprastructures were removed, a sonic toothbrush was provided with a new brush head at the 3 month follow-up, and the treatment time was double as compared to our study (1 minute versus 30 seconds). Therefore, although it could be hypothesized that these measures might have led to a more effective removal of the peri-implant biofilm, it did not result in a better treatment outcome. Nevertheless, it might be reasonable to extend the subgingival treatment time and remove the suprastructure to secure a thoroughly cleaned peri-implant area, especially in more advanced lesions (Mensi et al. 2020).