Shedding Light on the Therapeutic Efficiency of Oxygen-Releasing Gel and Photodynamic Therapy as Adjuvants in the Treatment of Experimental Periodontitis

<b><i>Objectives:</i></b> We aimed to compare the effectiveness of oxygen-releasing gel (Blue®M [BM]) alone or associated with photodynamic therapy (PDT), after scaling and root planing (SRP), as adjuvants during the treatment of ligature-induced experimental periodontitis (EP). <b><i>Materials and Methods:</i></b> For this aim, Wistar rats underwent EP by placing a cotton ligature around the lower first molar. Ligatures were maintained for 7 days and were subsequently removed. Then, rats were arbitrarily allocated into five groups: EP group-untreated animals; SRP group-SRP followed by the application of saline; BM group-SRP followed by the application of BM gel (0.4 mL); PDT group-SRP followed by photosensitizer and low power laser irradiation (660 nm, 40mW, 60 s); and BM+PDT-SRP followed by BM and later PDT. <b><i>Results:</i></b> Treatment with BM, PDT, and BM+PDT groups at both 7 and 30 days resulted in decreased alveolar bone destruction compared with the EP and SRP groups. At 30 days, the PDT and BM+PDT groups enhanced the resolution of inflammation by decreasing the inflammatory infiltrate and increasing alveolar bone neoformation, as evidenced by increased immunostaining of osteocalcin, transforming growth factor beta 1, bone morphogenetic protein-2, and -4. The BM group showed positive effects regarding the inhibition of bone resorption and inflammation but was less effective when compared with the PDT group. <b><i>Conclusion:</i></b> In conclusion, our findings demonstrate that PDT significantly reduces alveolar bone loss and enhances connective tissue repair. Treatment with BM gel alone also decreases bone loss and ameliorates the repair of periodontal tissues. However, combining BM with PDT appears to diminish the effects of PDT.