Signs, Symptoms, and Diagnosis of Osteonecrosis of the Jaw
- Exposure of mandibular or maxillary bone through non-healing lesions in the gingiva
- Presence of pain, inflammation, secondary infection, or drainage
- Lesions most commonly develop after invasive dental procedures or spontaneously
- Lesions are more common on the mandible than the maxilla
- Symptoms may include pain, neuropathy, erythema, suppuration, bad breath, and difficulty in keeping the mouth clean
- ONJ is classified based on severity, number of lesions, and lesion size
- Grades range from asymptomatic (grade 1) to severe (grade 4)
- Lesion size is measured as the largest diameter
- Multiple lesions can be present in ONJ
- Diagnosis involves evaluating symptoms and radiographic evidence
- Routine imaging techniques like radiographs are not effective in detecting cancellous bone and marrow damage
- No specific radiographic findings are exclusive to bone infarction/osteonecrosis
- Through-transmission alveolar ultrasound combined with panoramic dental radiography can help assess changes in jawbone density
- Up-to-date understanding of the disease process, detailed clinical findings, and various imaging modalities aid in early diagnosis
Causes and Risk Factors of Osteonecrosis of the Jaw
- Toxic agents, such as infections and chronic diseases, can affect blood flow and contribute to bone infarct and ischemia
- Heavy metals like lead and cadmium have been implicated in osteoporosis and hypofibrinolysis
- Bisphosphonates, commonly used for osteoporosis treatment, have been associated with osteonecrosis of the jaw (ONJ)
- Bisphosphonate-associated ONJ was first reported in cancer patients receiving chemotherapy
- Dental extractions are often a precipitating factor for ONJ in bisphosphonate users
- The mandible is more commonly affected than the maxilla in bisphosphonate-associated ONJ (2:1 ratio)
- Dental surgical procedures often precede ONJ cases
- Oversuppression of bone turnover is the primary mechanism for the development of bisphosphonate-associated ONJ
- Patients taking glucocorticoids like dexamethasone are at an increased risk of ONJ
- Matrix metalloproteinase 2 may be a candidate gene associated with bisphosphonate-associated ONJ
Management and Treatment of Osteonecrosis of the Jaw
- Antibiotics are ineffective in treating ONJ due to the lack of blood supply to the bone
- Surgical management, including the removal of necrotic bone, improves circulation and reduces microorganisms
- ONJ makes eating and drinking difficult, and surgical intervention can alleviate these challenges
- Bisphosphonate drugs have a prolonged embedding in bone tissues, increasing the risk of ONJ even after stopping the medication
- Bone health involves more than just bone mineral density, and bisphosphonates do not address all factors contributing to bone health
- Nutrient absorption and elimination of metabolic wastes are important in treatment
- Conservative debridement of necrotic bone, pain control, infection management, and use of antimicrobial oral rinses are preferred over aggressive surgical measures
- Complete cessation of bisphosphonate therapy for at least 6 months may show some improvement in non-surgical cases
- Repeat surgeries may be required for ONJ patients, especially in multiple sites within the jaws
- Research is ongoing to explore non-surgical therapeutic modalities that can improve prognosis and reduce morbidity
Effects and Pathophysiology of Osteonecrosis of the Jaw
- ONJ can have necrotic bone or bone marrow that is nutrient-starved
- Blood flow impairment occurs following a bone infarct
- Histopathological alterations include fatty degeneration, necrosis, and marrow fibrosis
- ONJ can affect the hips, knees, and jaws
- Infections in the oral cavity can worsen the blood flow problem in ONJ
- Cancellous bone is more susceptible to damage by bone infarcts
- Osteocytes have a lifespan of 15 years in cancellous bone and 25 years in cortical bone
- Altered osteoblastic function plays a role in ON of the femoral head
- Premature cell death can occur within 12-48 hours in bone cells
- Necrotic bone does not undergo resorption
- Histopathological changes in ONJ are similar to other forms of osteonecrosis
- Trabeculae in femoral head may have intact osteocytes but reduced collagen synthesis
- ONJ can cause severe facial pain and may be associated with neuralgia-inducing cavitational osteonecrosis (NICO)
History and Future Directions of Osteonecrosis of the Jaw
- ONJ has been documented since around 1850, with cases linked to environmental pollutants and medications containing mercury, arsenic, or bismuth
- The disease primarily targeted the mandible and caused localised or generalised deep ache or pain
- Diagnosis was often delayed due to the lack of visible clinical signs and limitations of imaging techniques
- Bone infarcts mediated by local and systemic factors are now recognised as the cause of ONJ
- Improved understanding and early diagnosis can be achieved through a combination of medical history, clinical findings, and imaging modalities
- Research is ongoing to develop effective treatments for bisphosphonate-associated bone lesions
- Minimizing or correcting known causes is crucial while further research is conducted on chronic ischemic bone diseases like ONJ
- Some osteonecrosis patients have responded to anticoagulation therapies alone
- The earlier the diagnosis, the better the prognosis for ONJ
- Greater emphasis on understanding and addressing the disease process is needed to reduce the morbidity of ONJ
Osteonecrosis of the jaw (ONJ) is a severe bone disease (osteonecrosis) that affects the jaws (the maxilla and the mandible). Various forms of ONJ have been described since 1861, and a number of causes have been suggested in the literature.
| Osteonecrosis of the jaws | |
|---|---|
| Other names | Osteonecrosis of the mandible |
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| Osteonecrosis of the jaw of the upper left jaw in a patient diagnosed with chronic venous insufficiency | |
| Specialty | Rheumatology  |
Osteonecrosis of the jaw associated with bisphosphonate therapy, which is required by some cancer treatment regimens, has been identified and defined as a pathological entity (bisphosphonate-associated osteonecrosis of the jaw) since 2003. The possible risk from lower oral doses of bisphosphonates, taken by patients to prevent or treat osteoporosis, remains uncertain.
Treatment options have been explored; however, severe cases of ONJ still require surgical removal of the affected bone. A thorough history and assessment of pre-existing systemic problems and possible sites of dental infection are required to help prevent the condition, especially if bisphosphonate therapy is considered.
