Antimicrobial Photodynamic Therapy Associated With Systemic Treatment in Osteoradionecrosis: An In Vivo Study

OBJECTIVE: To evaluate the effects of antimicrobial photodynamic therapy (aPDT), systemic pharmacological therapy, and their combination on irradiated mandibular post-extraction bone repair relevant to osteoradionecrosis (ORN) development in a rat model. METHODS: Twenty-six male Wistar rats were initially randomized into five experimental groups: non-irradiated extraction control, irradiated extraction plus systemic pharmacological therapy, irradiated extraction plus combined systemic pharmacological therapy and aPDT, irradiated extraction plus aPDT alone, and irradiated extraction without post-extraction treatment. The model included a single 20 Gy focal irradiation dose to the left mandible, followed by the first mandibular molar extraction 10 days later. During the experiment, some animals were lost due to procedural causes unrelated to treatment, resulting in final group sizes of 5, 5, 3, 4, and 6, respectively. The results were evaluated by micro-computed tomography (p = 0.02), radiographic examinations, histopathological analysis, and assessment of hepatic steatosis. RESULTS: Irradiated untreated animals showed the most pronounced structural and histopathological alterations. All treatment protocols improved bone repair compared with the irradiated untreated group. However, the combined protocol consistently showed the most favorable structural, radiographic, and histological findings, with better preservation of bone architecture and more organized osteogenesis. CONCLUSIONS: aPDT combined with systemic pharmacological therapy may represent a promising multimodal strategy for irradiated mandibular bone injury relevant to ORN development.