Osteonecrosis of the jaw (ONJ) is a condition where bone tissue in the jaw fails to heal and dies, often after an injury or disruption to its blood supply. This results in the bone becoming exposed through the gums. The condition is uncommon but serious, as the affected bone can become infected and cause significant pain and structural damage if not addressed.
Visual Signs of Osteonecrosis of the Jaw
The most definitive visual sign of ONJ is bone exposed through the gums that persists for more than eight weeks. This exposed area often appears yellowish-white and can be in the upper (maxilla) or lower (mandible) jaw. The site may resemble a tooth extraction socket that has failed to heal properly, leaving the jawbone uncovered by the surrounding gum tissue.
The exposed bone is often accompanied by changes in the surrounding soft tissues. The gums adjacent to the necrotic bone may become swollen, red, and inflamed as a response to the dead bone or a secondary infection. In many cases, pus or drainage from the area signifies an active infection and can contribute to bad breath.
Other signs include changes to the teeth and local structure. Teeth near the exposed bone may loosen as the supporting bone deteriorates. Patients might also report numbness or a “heavy jaw” sensation. Sometimes, the condition begins as a non-healing sore on the gums that eventually exposes the underlying bone.
Key Causes and Risk Factors
The development of ONJ is strongly linked to antiresorptive medications, such as bisphosphonates and denosumab, prescribed for osteoporosis and bone complications from cancer. These medications slow the natural process of bone breakdown. This interference can impair the jaw’s ability to repair itself after minor trauma, like a tooth extraction. The risk is particularly elevated for cancer patients receiving high doses of these drugs intravenously.
Radiation therapy to the head and neck is another significant cause, leading to a condition specifically termed osteoradionecrosis. Radiation can damage blood vessels that supply the jawbone, reducing its capacity for healing and regeneration. This makes the bone more susceptible to necrosis, especially following a dental surgical procedure.
Besides medication and radiation, other factors can increase the risk of developing ONJ, with invasive dental procedures like tooth extractions being common triggers. Contributing risk factors include:
- Chronic steroid use
- Pre-existing dental issues like gum disease
- Smoking
- Diabetes
- Trauma from poorly fitting dentures that create chronic sores
The Diagnostic Process
A diagnosis of ONJ begins with a clinical examination of the mouth by a dentist or oral surgeon. The practitioner will look for the sign of exposed bone and assess the health of the surrounding gums and teeth. A detailed review of the patient’s medical history is also necessary to identify risk factors, such as bisphosphonate use or a history of radiation therapy.
The defining diagnostic criterion is the persistence of exposed bone for eight weeks or longer, which helps differentiate ONJ from slow healing. If exposed bone is present without a history of radiation, and the patient has been taking relevant medications, the condition is specified as medication-related osteonecrosis of the jaw (MRONJ).
Imaging studies are used to determine the extent of bone damage not visible to the naked eye. Panoramic X-rays can provide a broad view of the jaw, revealing changes in bone density. For more detailed analysis, a computed tomography (CT) scan may be ordered. This imaging helps clinicians stage the condition’s severity, which guides the treatment plan.
Treatment and Management Strategies
The goals of managing osteonecrosis of the jaw are to control pain, resolve any secondary infection, and prevent the area of dead bone from expanding. Treatment approaches are tailored to the stage of the condition and the patient’s overall health. For early-stage ONJ, conservative, non-surgical management is the first line of defense.
Conservative treatment focuses on creating a clean oral environment and managing symptoms. This involves using antimicrobial mouth rinses to reduce the bacterial load and systemic antibiotics to treat active infections. Pain management is also a focus, with analgesics prescribed as needed. During this period, dental work is minimized to avoid further trauma to the jaw.
In cases where necrotic bone causes persistent pain, chronic infection, or a fracture, surgical intervention may be necessary. The most common procedure is a debridement, which involves removing the dead bone tissue until healthy, bleeding bone is reached. This allows the surrounding soft tissue to cover the area and promote healing. The decision to proceed with surgery is made carefully, as it carries risks to the fragile bone.