Effects of Infrared and Dual‐Wavelength Photobiomodulation Therapy on Mandibular Bone Healing Following Radiotherapy and Tooth Extraction: An Experimental Study
Göksal Keldal, Sefa Çolak, Asiye Yancı, Gülhan Güler Avcı, Rutkay Fırat Bulut, Bilal Bahar, Yunus Balel, Fikret GevrekABSTRACT
Background
Osteoradionecrosis (ORN) is a serious complication of head and neck radiotherapy characterized by impaired bone healing. Infrared photobiomodulation therapy (IR‐PBMT) and dual‐wavelength photobiomodulation therapy (Dual‐PBMT) have been proposed as non‐invasive approaches to enhance bone regeneration.
Methods
Twenty‐nine male Wistar–Albino rats were included. An experimental protocol designed to induce mandibular ORN was performed using a single 35 Gy radiation dose followed by mandibular molar extraction. Animals were allocated to four groups: control, radiotherapy plus extraction (RT + EX), RT + EX + IR‐PBMT, and RT + EX + Dual‐PBMT. IR‐PBMT was performed using a 940 nm diode laser, whereas Dual‐PBMT combined 632–650 nm red and 904–940 nm infrared wavelengths. Both PBMT protocols were applied extraorally for 14 consecutive days. Bone samples were evaluated histopathologically and immunohistochemically for alkaline phosphatase (ALP), bone morphogenetic protein‐2 (BMP‐2), osteonectin (ONC), and tartrate‐resistant acid phosphatase (TRAP).
Results
The RT + EX group exhibited severe inflammation and tissue destruction, whereas both PBMT‐treated groups showed reduced inflammation and partial epithelialization. Osteogenic marker expression was significantly lower and TRAP expression was significantly higher in the RT + EX group than in the control group ( p < 0.05). Compared with the RT + EX group, both IR‐PBMT and Dual‐PBMT significantly increased ALP, BMP‐2, and ONC expression and reduced TRAP expression ( p < 0.05). ALP expression was significantly higher in the Dual‐PBMT group than in the IR‐PBMT group, whereas no significant differences between the two protocols were observed for BMP‐2, ONC, or TRAP.
Conclusion
Both IR‐PBMT and Dual‐PBMT improved the evaluated histological and bone‐remodeling parameters following radiotherapy and tooth extraction. Because the control animals did not undergo tooth extraction, comparisons with the control group should be interpreted cautiously. Although Dual‐PBMT produced a greater increase in ALP expression, the findings do not demonstrate the overall superiority of one PBMT protocol over the other. Both approaches may represent promising adjunctive strategies for mitigating radiation‐associated impairment of mandibular bone healing.