Impact of Photobiomodulation and Melatonin on Periodontal Healing of Periodontitis in Immunosuppressed Rats

<b>Introduction:</b> Periodontitis is an inflammatory disease due to bacterial origin; it has a chronic course and progresses by immunosuppressive therapy. However, adjuvant therapies such as photobiomodulation (PBM) and melatonin can reduce the severity of the inflammation and inhibit the progression of periodontitis. Therefore, the present study evaluated the effects of PBM (PBM) and melatonin, as adjuvant therapies, on periodontal healing in immunosuppressed rats with periodontitis. <b>Methods:</b> Random allocation was performed on 36 albino Wistar rats, divided into the following groups: control, periodontitis, immunosuppressant only, immunosuppressant+PBM, immunosuppressant+melatonin, and immunosuppressant+melatonin+PBM. Periodontitis caused by ligature in all groups, except for the control group. Subcutaneous administration of dexamethasone was performed in the immunosuppressant groups for immunosuppression. All the groups except the control group received scaling and root planning (SRP). Each group was subdivided into three equal subgroups according to the evaluation period: (A), one week, (B) two weeks (C), 4 weeks. Histological examination was done with haematoxylin & eosin and Masson's Trichrome for inflammation and periodontal healing. Statistical Analysis of the data was done by using the chi-square test. The significance level was set at <i>P</i>≤0.05. <b>Results:</b> Regarding the inflammatory response and periodontal healing, histological examination revealed statistically significant difference in all treated groups in comparison with the control untreated immunosuppressed group (<i>P</i><0.001). The combined application of melatonin and PBM resulted in a best histological response presented by lower inflammatory response and better periodontal healing, when compared with all other treated groups (<i>P</i><0.001). <b>Conclusion:</b> After considering the circumstances of this research, the combination of melatonin and PBM by a 650 nm diode laser with output power of 100 mw for one minute for three sessions appeared to be a beneficial adjunct in periodontal healing in immunosuppressed rats with periodontitis.