Anti-infective therapy of peri-implantitis with adjunctive local drug delivery or photodynamic therapy: six-month outcomes of a prospective randomized clinical trial

Objective To compare the adjunctive clinical effects in the non-surgical treatment of peri-implantitis with either local drug delivery (LDD) or photodynamic therapy (PDT). Material and methods Forty subjects with initial peri-implantitis, i.e. pocket probing depths (PPD) 46 mm with concomitant bleeding on probing (BoP) and marginal bone loss ranging from 0.5 to 2 mm between delivery of the reconstruction and pre-screening appointment were randomly assigned to two treatment groups. All implants underwent mechanical debridement with titanium curettes, followed by a glycine-based powder airpolishing. Implants in the test group (n = 20) received adjunctive PDT, whereas minocycline microspheres were locally delivered into the peri-implant pockets of control implants (n = 20). At sites with residual BoP, treatment was repeated after 3 and 6 months. The primary outcome variable was the change in the number of sites with BoP. Secondary outcome variables were changes in PPD, in clinical attachment level (CAL), and in mucosal recession (REC). Results After 3 months, implants of both groups yielded a statistically significant reduction (P < 0.0001) in the number of BoP-positive sites compared with baseline (LDD: from 4.41 +/- 1.47 to 2.20 +/- 1.28, PDT: from 4.03 +/- 1.66 to 2.26 +/- 1.28). After 6 months, complete resolution of mucosal inflammation was obtained in 15% of the implants in the control group and in 30% of the implants in the test group (P = 0.16). After 3 months, changes in PPD, REC, and modified Plaque Index (mPlI) were statistically significantly different from baseline (P < 0.05). No statistically significant changes (P > 0.05) occurred between 3 and 6 months. CAL measurements did not yield statistically significant changes (P > 0.05) in both groups during the 6-month observation time. Between-group comparisons revealed no statistically significant differences (P > 0.05) at baseline, 3 and 6 months with the exception of the mPlI after 6 months. Conclusions In cases of initial peri-implantitis, non-surgical mechanical debridement with adjunctive use of PDT is equally effective in the reduction of mucosal inflammation as with the adjunctive use of minocycline microspheres up to 6 months. Adjunctive PDT may represent an alternative treatment modality in the non-surgical management of initial peri-implantitis. Complete resolution of inflammation, however, was not routinely achieved with either of the adjunctive therapies.