Clinical findings, epidemiology, etiology, and pathophysiology - Area of exposed bone that does not heal - Numbness or paresthesias within the mouth or jaw - Pain - Swelling - Non-healing sore or ulcer in the mouth - Incidence of osteoradionecrosis estimated at around 2% - Improvement in radiation therapy has decreased the incidence - Radiation therapy causes DNA damage and cell death - Tumor cells are more susceptible to radiation damage - Excessive radiation doses can cause normal cells to be overwhelmed by DNA damage - ORN is the result of cumulative tissue damage caused by radiation - Radiation creates disturbances in cell metabolism and homeostasis - Hypovascular environment due to injury to endothelial cells - Decreased oxygen delivery leads to hypoxic tissues - ORN is essentially hypocellular-hypovascular-hypoxic tissues

Risk factors, prevention, and treatment - Size and location of tumor - Dose and delivery of radiation - Smoking - Diabetes mellitus - Presence of dental disease - Prevention strategies aim to avoid excess doses of radiation - Maintaining excellent dental hygiene can help prevent ORN - Treatments vary depending on disease severity - Medical treatment with antibiotics - Hyperbaric oxygen therapy (HBO) or surgical debridement/reconstruction can be used as treatments

Staging and prevention - Staging system provides baseline reference for management after diagnosis - No universally accepted prevention and management - Many proposed preventive approaches lack high quality evidence - Lack of evidence to determine most effective approach - Uncertainty for clinicians and patients in choosing treatment - Dental assessment recommended before radiotherapy - Strict preventive regime paired with IMRT can prevent ORN - Dental extractions are a major risk factor but not recommended as treatment - Frequency of ORN similar in pre- and post-radiotherapy extractions - Teeth extraction should consider prognosis, oral care, and patient's wishes - Tooth brushing technique and habit should be high standard - Chlorhexidine mouthwash and fluoride regime encouraged - Tailored oral care for trismus and altered taste - High level of motivation and regular dental appointments important - Denture adjustments to avoid ORN secondary to trauma

Management options - Antiseptic mouthwashes and analgesics for acute ORN - Tetracyclines and penicillin antibiotics to eliminate infection - Ultrasound therapy improves blood circulation and induces healing - Hyperbaric oxygen therapy (HBO) recommended by some studies - Conservative approaches to manage ORN - Hyperbaric Oxygen Therapy (HBO) - First described in 1973 as an adjunctive treatment for ORN - Increases tissue oxygen tension - Improves collagen synthesis, angiogenesis, and epithelialization - Controversial use as the only method for ORN management - Little evidence of clinical benefit and questionable therapeutical significance - Surgical Management - Multidisciplinary approach combining HBO therapy and surgery - Improves local blood circulation - Resection of necrotic bone and reconstruction with a free flap - Some studies question the benefit of HBO therapy - Microvascular reconstruction without HBO therapy is successful - Pharmacological Methods - Pentoxifylline enhances blood flow and reduces cytokine cascade - Tocopherols (vitamin E) inhibit platelet aggregation and scavenge reactive oxygen species - Clodronate inhibits bone resorption and increases bone formation - Pharmacological methods target etiologic factors of ORN - Pentoxifylline not meant for long-term treatment of ORN - Surgical Procedures - Removal of small sequestra - Sequestrectomy - Alveolectomy with primary closure - Closure of orocutaneous fistula - Large resections for advanced disease or failed conservative measures

References (not included in the content grouping)