## 3 Results
### Group 3--Use of Diode Laser in Peri-Implantitis Treatment (Table 3)  
Photodynamic therapy (PDT) with diode laser in the non-surgical therapy of peri-implantitis was studied by [PERSON] [19]. Forty subjects with 4-6 mm PPD, bleeding on probing and marginal bone loss were randomly divided into two groups, according to the administered treatment. Patients in the control group received exclusively local drugs delivery (LLD) in the peri-implants pocket. After 3 months of healing, implants showed a significant BOP reduction (\(p<0.0001\)) compared to the initial situation in both groups. After 6 months, complete resolution of the mucosal inflammation was found in 30% of cases treated with PDT and 15% in the LDD group. The authors conclude their analysis by stating that the adjunctive PDT may represent a reliable treatment in the non-surgical therapy of peri-implantitis. [PERSON] et al. presented the outcomes of the same study but with a follow-up of 12 months. The authors observed a statistically significant (\(p<0.05\)) decrease in PPD from baseline after conventional treatment followed by laser irradiation [20]. In accordance with the results of this study, mechanical treatment accompanied by photodynamic therapy could favor an improvement of clinical parameters in cases of mild or moderate peri-implantitis. Positive effects of the diode laser in the PDT mode on the treatment of PI with PPD \(<5\) mm were highlighted also by [PERSON] [21]. The evaluation was conducted in patients with mild (PPD less than 5 mm) and severe (PPD more than 5 mm) PI. In all patients, a reduction of BOP and PPD was observed 3 months after conventional non-surgical therapy followed by diode laser irradiation. However, in the patients affected by severe PI, BOP reduction was not maintained, and a slight increase in PPD was observed after 6 months. [PERSON] et al. divided 20 patients in four groups: two test groups treated with photodynamic therapy + conventional manual therapy (PDT + CT) and two control groups treated only with conventional therapy (CT) [22]. Patients were also divided into two groups according to bore defects' depth (\(\leq\)2 mm or \(\geq\)2 mm). In defects more than 2 mm, a mucoperiostel flap was carried out. CT consisted in scaling associated to chlorhydamine irrigation; PDT consisted in applying blue into peri-implantitis site and irradiating it with a diode laser for 1.5 min in a continuous wave mode. Immediately after treatment, bacterial-count results showed a 93.6% reduction in the PDT + TC group and 83.5% in the control group. However, a recolonization of some bacterial species emerged at 6 months. The authors concluded that PDT can be effectively used as a supplement to conventional therapy. [PERSON] tested the effectiveness of the adjunctive diode laser irradiation during the surgical treatment of peri-implantitis [23]. Nineteen patients were enrolled in this clinical trial, and, on all of them, surgical regenerative therapy of the peri-implant infrabony defects was performed. Only for 10 randomly chosen patients (test group) was an additional irradiation with diode laser performed, with the aim to improve the decontamination of the infected implant parts and of the surrounding tissues. Clinical peri-implant indices (CAL, PPD, BOP and PI) were recorded into clinical chart at the baseline and at 3 and 6 months after treatment. Patients who received additional laser therapy showed a better CAL gain, but no substantial differences were found regarding the efficiency in the reduction of the other analyzed indices at 3 and 6 months after surgery (\(p<0.05\)). Therefore, following the results obtained in this study, the additional use of the diode laser does not seem to have given supplementary clinical advantages in surgical management of peri-implantitis [23]. [PERSON] et al. treated 23 patients affected by mucositis (PiM) and initial peri-implantitis (Pi) [24].