Abstract: Objective To investigate the short-term clinical curative effects of Er:YAG laser on the treatment of peri-implantitis, hoping to be of help to the clinical treatment of peri-implantitis in the future. Methods 20 patients with peri-implantitis were randomly recruited and grouped after meeting the inclusion and the exclusion criteria. They were divided into conventional scaling treatment group and laser irradiation treatment group. Periodontal clinical indicators were recorded before treatment (baseline level), 3 months after treatment, and 6 months after treatment. All of the indicators included modified plaque index (mPLI), bleeding on probing (BOP), modified sulcus bleeding index (mSBI), probing depth (PD),attachment level (ALP). All of the indicators were measured and averaged at 6 sites of each implant: the mesial side, the buccal center, the distal mesothelial side, the mesial lingual side, the lingual center, and the distal lingual side. A periodontal probe (PCP 12) was used for all examinations. Results At the baseline level, clinical periodontal parameters were similar between the experimental group and the control group, and there was no significant difference after statistical analysis (P>0.05). At 3 months after treatment, all clinical periodontal indicators were reduced compared with baseline levels, and the rate of the decrease of the laser irradiation treatment group was bigger than the conventional scaling treatment group, and the decrease was statistically significant (P＜0.05). At 6 months after treatment, the overall clinical periodontal indexes were still below the baseline, but compared with the results at 3 months after treatment, except the lower BOP, the other periodontal indexes had a little bit of increase. Conclusion All the tested clinical periodontal indexes of patients with peri-implantitis can be improved by the treatment of conventional scaling and laser irradiation. And the laser irradiation treatment has more obvious, but less stable effects. However, this improvement may just be short-term, and the long-term efficacy may depend on a long-term observation and follow-up of larger samples.

Key words: peri-implantitis, non-surgical periodontitis, Er:YAG laser irradiation