); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (S.C)1 School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; [EMAIL_ADDRESS] (P.C. ); [EMAIL_ADDRESS] (A.L. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (S.C)1 School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; [EMAIL_ADDRESS] (P.C. ); [EMAIL_ADDRESS] (A.L. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (S.C)1 School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; [EMAIL_ADDRESS] (P.C. ); [EMAIL_ADDRESS] (A.L. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (S.C)1 School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; [EMAIL_ADDRESS] (P.C. ); [EMAIL_ADDRESS] (A.L. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (S.C)1 School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; [EMAIL_ADDRESS] (P.C. ); [EMAIL_ADDRESS] (A.L. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (S.C)1 School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; [EMAIL_ADDRESS] (P.C. ); [EMAIL_ADDRESS] (A.L. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (M.B. ); [EMAIL_ADDRESS] (M.B. ); saverio.ceraulo@unimib. rather, is a condition that is characterized by inflammation in the peri-implant mucosa, progressive bone loss (radiographic bone loss compared to previous examinations), bleeding on probing and/or suppuration, increased probing depths and/or recession of the mucosal margin [1]. [PERSON] et al. [2] stated that risk factors for peri-implantitis insurgence are history of chronic periodontitis and poor plaque control with the absence of an appropriate maintenance protocol; other factors with less evidence of involvement in peri-implantitis are smoking, diabetes, persistence of submucosal cement, lack of keratinized mucosa and implant positioning. Peri-implantitis treatments are mainly directed to removing bacterial biofilm from the contaminated surfaces and to provide more suitable access to implant surfaces in order to facilitate maintenance procedures. The treatments proposed involve both nonsurgical and surgical therapies; the nonsurgical approach is represented by mechanical decontamination, antibiotics and antiseptics; the surgical approach includes air-powered abrasives, resective surgery and regenerative surgery. Moreover, an important treatment option that can be added to the abovementioned therapies is represented by surface decontamination with chemical methods (citric acid, EDTA, hydrogen peroxide, saline solution) or lasers [3]. Laser therapy has been demonstrated to be effective in peri-implantitis management; in the literature, the use of an Er:YAG laser, CO\({}_{2}\) laser and photodynamic therapies (PDTs) [4], that can be defined as the eradication of target cells by reactive oxygen species using a photosensitizer and light of an appropriate wavelength, has been proposed. It may be an alternative to produce an effect on target bacteria directly in the site of infection, bypassing problems related to antibiotics [5; 6; 7; 8; 9]. \"Photodynamic therapy involves three components: a photosensitizer, light and oxygen. When a photosensitizer is irradiated with a light of a specific wavelength it undergoes a transition from one state to the low energy of a singlet excitation state. Consequently it can decay to its previous state, with fluorescence emission, or may undergo a transition to a triplet state of higher energy. The triplet state can react with the endogenous oxygen to produce singlet oxygen and other radicals, causing a rapid and selective destruction of the target tissue.