BACKGROUND: The primary aim of this systematic review is to address the following focused question: Is laser therapy, as a monotherapy or as an adjunctive therapy, an efficacious treatment modality for patients with peri-implantitis?METHODS: The PubMed database of the U.S. National Library of Medicine and the Cochrane Central Register of Controlled Trials were electronically searched, complemented by manual searches up to June 2013.RESULTS: The search yielded 137 titles and abstracts. After initial screening, 15 of 137 publications were scrutinized during the second phase of the review. In the second phase, nine articles were excluded from the analysis and six controlled, clinical studies were selected. Narrative synthesis of the results revealed that non-surgical laser treatment with a single application of either an erbium:yttrium-aluminum-garnet (Er:YAG) (2,940-nm) laser or a diode (660-nm) laser in combination with a phenothiazine chloride dye is efficient in controlling inflammation around treated implants for at least 6 months following intervention, whereas it has only a mild effect on reduction in probing depth (PD) and gain in clinical attachment level (CAL). There is limited information regarding the clinical application of the CO2 (10.6-µm) laser in the surgical treatment of peri-implantitis; however, its use may be promising. A meta-analysis could be performed only for the efficacy of Er:YAG laser due to the heterogeneity of the studies and the limited amount of data available. Meta-analysis did not reveal statistically significant evidence for treatment effects in reducing PD and CAL levels in comparison to controls.CONCLUSIONS: Based on the limited information currently available, any superiority of laser treatment in comparison to conventional treatment of peri-implantitis could not be identified. Considering the high heterogeneity and the low number of included studies, the authors cautiously conclude that non-surgical laser therapy may be investigated as phase I therapy for the treatment of peri-implantitis. Future research should emphasize detailed description of the specific laser characteristics and power settings in clinical studies.