Irradiation Induced Biochemical Changes in Human Mandibular Bone: A Raman Spectroscopic Study

Abstract

Understanding the biochemical changes in irradiated human mandible after radiotherapy of cancer patients is critical for oral rehabilitation. The underlying mechanism for radiation-associated changes in the bone at the molecular level could lead to implant failure and osteoradionecrosis. The study aimed to assess the chemical composition and bone quality in irradiated human mandibular bone using Raman spectroscopy. A total of 33 bone biopsies from 16 control and 17 irradiated patients were included to quantify biochemical parameters from Raman spectra. The differences of bone mineral and matrix band intensities between control and irradiated groups were analyzed using unpaired student's t-test with statistical significance at p<0.05. The intensity of the phosphate band is significantly decreased and the carbonate band is significantly increased in the irradiated group. Further, the mineral crystallinity and carbonate to phosphate ratio are increased and the mineral to matrix ratio is decreased in the irradiated group. The Principal Component Analysis plotting based on the local radiation dose and biopsy time interval of irradiated samples did not show any specific classification between irradiation sub-groups. Irradiation disrupted the interaction and bonding between the organic matrix and hydroxyapatite minerals that may affect the deterioration of bone biochemical properties. However, the normal clinical appearance of irradiated bone would have been accompanied by underlying biochemical and microscopical changes which might result in radiation-induced delayed complications.

Microstructural changes in the irradiated and osteoradionecrotic bone: a SEM study

“…18 Hence, this causes difficulty in transposing results to the jawbone. A recent Raman spectroscopy study 19 has shown that radiation could alter the biochemical composition of the human mandible thereby affecting the quality and mechanical competence of bone. This increases radiation-associated risks and could contribute to the pathophysiology of ORN.…”

Rehabilitation of head and neck cancer patients: aspects determining implant placement

“…Several animal studies have shown that radiotherapy has a negative effect on peri-implant bone regeneration, although sufficient osseointegration can be achieved [54][55][56] . More recently, spectroscopic and quantitative studies of irradiated bone samples of human mandibles in humans have been published [57][58][59][60] . These studies show decreased vascularity, early death of osteocytes and osteoblasts leading to a decrease in bone turnover with a critical threshold of 50 Gy leading to more detrimental effects.…”