Antimicrobial photodynamic therapy Shows Promise in Preventing Osteoradionecrosis of Jaw: Study

A total of 26 Wistar male rats were randomly divided into five separate experimental groups that differed in pathways of the treatment: the non-irradiated extraction control group, the irradiated extraction group undergoing only the systemic pharmacological treatment, the irradiated extraction group undergoing both the systemic therapy and aPDT treatment, the irradiated extraction group undergoing only aPDT treatment, and the irradiated extraction group without any treatment after extraction. The initial step of the experimental protocol included administering a one-time dose of 20 Gy of radiation in a focal manner directed to the left mandible. Exactly 10 days after such a procedure allowing acute damage of the tissue to appear, animals underwent surgical extraction of the left first mandibular molar.

Some of the animals were lost during the experiment for the reasons totally irrelevant to the therapeutic procedures used; this fact led to a change in the numbers of animals in groups to 5, 5, 3, 4, and 6, respectively. All therapeutic procedures have been thoroughly evaluated based on the use of high-resolution micro-computed tomography, structural radiographic examination, histopathological examination of the mandibles, and the systemic toxicity evaluation of hepatic steatosis.

Key findings:

• For the preclinical experiment, the initial randomization involved 26 male Wistar rats distributed among five separate experimental groups.
• There were a few procedural losses not related to the interventions themselves, which meant that the actual number of subjects in each analyzed cohort was 5, 5, 3, 4, and 6 animals, respectively.
• The model provided the experimental setting for the serious tissue injury via a single 20 Gy focal radiation exposure to the left mandibular region 10 days before surgery of tooth extraction.
• The irradiated and totally untreated subjects revealed the most intense and extensive structural and histopathological changes, including poor bone filling and disorganized tissue architecture.
• All the treatment procedures provided the significant improvement of bone healing in comparison with the irradiated untreated group, confirmed by the micro-computed tomography (p = 0.02).

In summary, aPDT in combination with systemic pharmacological treatment seems to be an innovative multimodal approach in treating irradiated mandibular bone damage related to ORN. The findings from this conclusive study provide a necessary empirical basis for the contemporary maxillofacial treatments, showing that a combined treatment modality is better than the traditional one.

Reference:

L. L. Fonseca, L. d. R. P. Queiroz, A. L. O. Costa, et al., “Antimicrobial Photodynamic Therapy Associated With Systemic Treatment in Osteoradionecrosis: An In Vivo Study,” Lasers in Surgery and Medicine0 (2026): 1–10. https://doi.org/10.1002/lsm.70163.