Osteoradionecrosis of the jaw: signs, prevention and treatment

Radiotherapy to the head and neck saves lives, and it can leave the jawbone less able to repair itself for years afterwards. Osteoradionecrosis of the jaw, usually shortened to ORN, is one of the most serious of those late effects. This guide covers what it is, who is most at risk, the signs to report, how dental care lowers the risk, and what the treatment evidence actually shows, including the honest and largely negative picture for hyperbaric oxygen.

What is osteoradionecrosis of the jaw?

Macmillan Cancer Support explains that radiotherapy to the head and neck can affect the blood supply to the jawbone, and that this might cause tissue in the bone to die. When that happens, the bone struggles to heal after even minor injury, such as a tooth extraction or a denture rubbing the gum.

It is not rare. In a 2024 study in the Journal of Clinical Oncology, ORN was identified in 219 of 2,732 people (8%) treated with modern intensity-modulated radiotherapy for head and neck cancer at one Canadian centre between 2011 and 2017. It can affect the lower jaw (mandible) or the upper jaw (maxilla), and the same study found that older classification systems failed to recognise upper jaw cases.

Who is most at risk?

The same study found higher risk in people who had:

• cancers of the mouth (oral cavity) or oropharynx
• a radiotherapy dose to the area of 60 Gy or more
• a current or past smoking habit
• advanced gum (periodontal) disease

The high-risk group developed ORN at 12.7%, against 3.1% in the lower-risk group. Macmillan also lists everyday risk factors: surgery, having a tooth removed, a dental infection, a broken filling or sharp tooth injuring the gum, and badly fitting dentures that cause an ulcer.

What are the symptoms?

According to Macmillan, ORN can cause:

• pain, numbness or a feeling of heaviness in the jaw
• a rough area on the gum, or bone showing through it
• swelling around the gum
• loose teeth
• tiny pieces of bone coming away in the mouth

Many of these have other causes, which is exactly why they need looking at. Tell your dentist, GP or hospital team if you notice any of them after head and neck radiotherapy, even years later.

How does dental care lower the risk?

The strongest recommendations in the 2024 international guideline from ISOO, MASCC and ASCO concern prevention and surgical management. In practice, UK hospital advice follows a familiar pattern:

• Before radiotherapy: a thorough dental check. Badly broken down or infected teeth may be removed beforehand to reduce later risk, according to Hull University Teaching Hospitals NHS Trust.
• For life afterwards: high-fluoride toothpaste used as prescribed, regular dental visits at the interval your team sets, and fewer sugary and fizzy drinks.
• Smoking and alcohol: stopping smoking and cutting down on alcohol are both advised. Macmillan notes that smoking affects the blood supply to the bone.
• If a tooth must come out: Macmillan advises that extractions after radiotherapy are best planned with a specialist oral and maxillofacial surgeon.
• Dentures: make sure they fit well and do not rub.

How is osteoradionecrosis staged?

Doctors grade ORN so they can match treatment to severity. The ClinRad system, developed in the 2024 study above, grades ORN by how far the dead bone extends vertically on imaging and whether there is exposed bone or a fistula (a channel through to the skin or mouth). It outperformed 15 older systems at picking out serious events such as jaw fracture, and a 2025 study in Radiotherapy and Oncology notes it is endorsed by ASCO, ISOO and MASCC. Your team may use a different scale, but the principle is the same: small, early areas are managed very differently from advanced disease.

How is osteoradionecrosis treated?

Treatment depends on stage. Macmillan lists antibiotics for infection, surgery to remove dead bone, and in severe cases reconstruction of the jaw.

Conservative care. The standard care arm of the UK RAPTOR trial describes pain relief, mouthwash, antibiotics and reducing local trauma to the area.

Pentoxifylline-based medicines. Pentoxifylline with vitamin E (tocopherol), sometimes with a third drug called clodronate (the combination is known as PENTOCLO), is used by some teams. The evidence is still early. A French phase II study of 54 people with refractory ORN of the lower jaw reported complete recovery in all of them after a median of 9 months, but it had no comparison group and its authors said a randomised trial was needed. A Gloucestershire Hospitals NHS leaflet describes the treatment as experimental because no randomised trials have been published. The RAPTOR trial, planned across about 15 UK centres with 120 patients, is now testing PENTOCLO against standard care.

Surgery. Advanced ORN, especially with fracture or fistula, may need removal of the affected bone and reconstruction.

Does hyperbaric oxygen help osteoradionecrosis?

Hyperbaric oxygen has long been advocated to prevent and treat ORN, on the reasoning that more oxygen could help poorly supplied bone. Better trials have made that much less certain.

Prevention after extraction. The UK HOPON trial, published in 2019, randomised 144 people who needed extractions or implants in a lower jaw that had received more than 50 Gy. Everyone had antibiotics and chlorhexidine mouthwash; half also had 30 daily sessions of 100% oxygen at 2.4 ATA for 80 to 90 minutes. At 6 months, ORN was diagnosed in 6.4% of the hyperbaric group and 5.7% of the control group, among the 100 people analysed. The hyperbaric group had fewer short-term symptoms but no difference in later pain or quality of life. The authors concluded that hyperbaric oxygen for these procedures was unnecessary.

The wider review. The 2023 Cochrane review of late radiation tissue injury pooled 18 randomised trials with 1,071 participants. For ORN, pain scores improved slightly at 12 months (2 trials, 157 participants, moderate certainty). Overall, it found that hyperbaric oxygen may be associated with improved outcomes in late radiation injury of the head and neck, bladder and rectum, but called for cautious interpretation because the studies were small. It also recorded harms: a higher risk of reduced visual sharpness, usually temporary, and ear barotrauma. The trials used between 2.0 and 3.0 ATA, most at 2.4 or 2.5 ATA.

The guideline view. The 2024 ISOO, MASCC and ASCO guideline concluded that hyperbaric oxygen for preventing and managing ORN "remains largely unjustified, with limited evidence to support its practice."

So where it is still considered, it is a specialist hospital decision made by the head and neck team, not a first step.

Where does HBOT Medics fit?

Plainly: we are not an ORN service. Our single-person chamber runs at 1.5 ATA, well below the pressures used in these trials, and a private course here is not a substitute for a head and neck, maxillofacial or hospital hyperbaric pathway. If you have symptoms of ORN, the right people to see are your dentist and your cancer team.

We also do not offer hyperbaric oxygen as a treatment for cancer itself. Our article on HBOT and cancer explains that distinction. If you want to understand the therapy more generally, start with what hyperbaric oxygen therapy is and who it is not suitable for.