What Is an Irradiated Jaw?
An irradiated jaw refers to the range of biological changes that develop in the jawbone following radiotherapy to the head and neck, usually for cancer of the mouth, larynx, pharynx or salivary glands.
It presents a particularly complex clinical challenge because the underlying changes are not immediately visible. They may become apparent much later, when the tissue is required to respond to trauma or another biological stress.
The irradiated jaw has a depleted blood supply, a reduced osteoblast population and chronic hypoxia. Under these conditions, even a simple tooth extraction—a routine procedure in healthy tissue—may trigger osteoradionecrosis, a progressive necrotic process that persists because the tissue is unable to heal effectively.
The risk remains elevated for decades after radiotherapy.
Characteristics of the Irradiated Jaw
The pathophysiology of radiation-induced injury to the jaw follows the classic Marx model: hypoxia, hypovascularity and hypocellularity.
Radiation damages the vascular endothelium and reduces vascular density, leaving bone tissue unable to receive sufficient oxygen, nutrients or immune support.
Of particular importance is the fact that radiation-induced injury progresses over time. The jaw gradually becomes more vulnerable rather than less so. Patients who completed radiotherapy years or even decades earlier continue to require special precautions and protective measures before undergoing any invasive dental procedure.
Scientific Studies and Evidence
The scientific evidence supporting the use of hyperbaric oxygen therapy in the irradiated jaw is among the strongest in the field.
The landmark randomized study by Marx, which evaluated patients undergoing dental extractions in irradiated jaws, reported a marked reduction in the incidence of osteoradionecrosis among those who received hyperbaric oxygen therapy, at 5.4%, compared with 29.9% among those who did not.
These findings led to the establishment of a prophylactic hyperbaric oxygen protocol before invasive dental procedures involving irradiated jawbone, an approach now recognized by international organizations in oral and maxillofacial surgery and hyperbaric medicine.
The Role of Hyperbaric Oxygen Therapy
In the irradiated jaw, hyperbaric oxygen therapy is used for two distinct purposes.
The first is prophylactic. Before an invasive dental procedure, such as an extraction, implant placement or surgery, 20 sessions of hyperbaric oxygen therapy may be administered to improve the biological condition of the irradiated tissue and substantially reduce the risk of osteoradionecrosis. These are followed by 10 postoperative sessions to support healing.
The second purpose is therapeutic. In patients who have already developed osteoradionecrosis, hyperbaric oxygen therapy may form a key part of the treatment plan by improving tissue viability, creating more favorable conditions for surgery and reducing the risk of recurrence.
Treatment is always planned in close collaboration with the oral and maxillofacial surgeon and the oncologist.