Osteoradionecrosis (ORN) is a serious complication of radiation therapy in cancer treatment where radiated bone becomes necrotic and exposed. ORN occurs most commonly in the mouth during the treatment of head and neck cancer, and can arise over 5 years after radiation. Common signs and symptoms include pain, difficulty chewing, trismus, mouth-to-skin fistulas and non-healing ulcers. The pathophysiology of ORN is fairly complex and involves drastic changes to bone tissue as a result of DNA damage and cell death caused by radiation treatment. Radiation therapy targeting tumor cells can affect normal cells as well, which can result in the death of bone tissue. Advances in radiation therapy have decreased the incidence of ORN, estimated at around 2%. Certain risk factors including the size and location of tumor, history of smoking or diabetes, and presence of dental disease can affect the chances of developing ORN. Osteoradionecrosis is difficult to prevent and treat. Current prevention strategies are aimed at avoiding excess doses of radiation as well as maintaining excellent dental hygiene. Treatments are variable depending on the provider and disease severity, and can range from medical treatment with antibiotics to hyperbaric oxygen therapy (HBO) to surgical debridement or reconstruction. Clinical findings
There are not many specific clinical signs of ORN. It may be first seen as an area of exposed bone which is not healing, or the non-specific signs may become evident prior to this. Symptoms vary depending on the degree of ORN that has occurred. Early indicators may be numbness or paresthesias within the mouth or jaw.
Extractions should be completed with as little trauma as possible, and on simple extractions of mobile teeth
Primary closure for firm teeth, by a minimal periosteal flap and alveolectomy
An experienced operator
Possibly pre-operative hyperbaric oxygen for mandibular molars in areas of high radiation
Review 5 days post-extraction and weekly review after  until healing is complete. Antibiotics
Majority of studies on ORN have recommended the use of prophylactic antibiotic where extractions are needed post-radiotherapy, although there is no universally agreed choice, timing and course duration of antibiotic regime.In one study, it was discovered that cases after 1986, the incidence of ORN after extractions post-radiotherapy was 3.6% in antibiotic prescribed cases and 2.6-3.4% in cases where there is no report on the prescription of antibiotics, showing no difference in reducing the risk of ORN and possibly reconsidering antibiotic regime in preventing ORN. Hyperbaric oxygen therapy
Results since 1986 have shown of far lower rates of ORN incidence, even without HBO (3.1-3.5%) and even a slightly higher rate for HBO patients (4.0%). Prophylactic use of HBO has been recommended in some studies  with a Cochrane review suggesting evidence for some reduction in ORN. However, the use of HBO prophylaxis is not agreed by others due to the insufficient evidence. Majority of British maxillofacial surgeons who participated in a survey recommended prophylactic HBO but protocols are varied. Management
Conservative
Antiseptic mouthwashes: Mouthrinses such as 0.02% aqueous chlorhexidine and saline can be used in acute ORN together with analgesics and anti-inflammatory drugs.