At the end of the 4-day experimental period, the implants were carefully removed from the splints by breaking the resin caps that held them in place. Each implant was randomly assigned to a treatment method (Cont, control (no decontamination); G, gauze soaked in saline; US, ultrasonic scaler (SUPRASSON P-MAX, Satelec-Acteon Group, Bordeaux, France; power setting: P5, tip: Implant Protect IP3L/R); Air, air abrasive (AIR-FLOW MASTER PIEZON®, EMS, Nyon, Switzerland; power setting: water flow 100%, air pressure 75%, powder: AIR-FLOW® PERIO POWDER, nozzle: PERIO-FLOW® nozzles, distance from the nozzle to the implant 2 mm); Rot, Rotary stainless steel instrument (iBrush, NeoBiotech©, Los Angeles, CA, USA; rotating speed 1500 rpm); Las, Er:YAG laser (Erwin AdvErL, J.Morita©, Kyoto, Japan; power setting 60 mJ/pulse, 10 pps, tip C600F, distance from the tip to the implant 2 mm) according to the random number table generated by a spreadsheet software (random number table generator: Excel® for Mac 2011, version 14.7.2, Microsoft®) (Fig. 3). All methods, including Cont, were applied to each set of 6 implants. One investigator (M.O) was blinded to which implant was assigned to which method. The investigator was experienced in using each method to treat peri-implantitis in clinical practice. The implant driver was connected to the implants to hold them without touching with the implant surface during decontamination. The implants were decontaminated by their assigned method, apart from those assigned to the Cont group, for 1 (one) min. After cleansing, decontaminated implants were immediately stored in a phosphate-buffered saline solution. Qualitative SEM analysis was performed using samples taken from the participant who had shown average plaque accumulation on the implant surface in the preliminary study (data not shown), and quantitative colony-forming unit (CFU) counts were taken care using the remaining 10 participants’ samples.