Osteonecrosis of the jaw, commonly called ONJ, occurs when the jaw bone is exposed and begins to starve from a lack of blood. Most cases of osteonecrosis of the jaw happen after a dental extraction. Osteo means bone and necrosis means death. As the name indicates, the bone begins to weaken and die with OJN, which usually (but not always), causes pain.
ONJ is associated with cancer treatments (including radiation), infection, steroid use, or antiresorptive medications used for osteoporosis. Examples of antiresorptive medications include bisphosphonates such as alendronate (Fosamax); risedronate (Actonel and Atelvia); ibandronate (Boniva); zoledronic acid (Reclast), and denosumab (Prolia).
ONJ is much more common in those patients who use these medications for cancer of the bone treatment. When used for osteoporosis in much lower doses, it is very rare.
While ONJ is associated with these conditions, it also can occur without any identifiable risk factors.
Osteonecrosis of the jaw is a condition in which an area of jawbone is not covered by the gums, a condition of poor healing. The condition must last for more than eight weeks to be called ONJ. When the bone is left uncovered, it does not receive blood and begins to die. ONJ most often develops after an invasive (surgical) dental procedure such as dental extraction. ONJ also may occur spontaneously over boney growths in the roof or inner parts of the mouth.
ONJ has occurred in patients with herpes zoster virus infections, in those who are undergoing radiation therapy of the head and neck (radiation osteonecrosis), osteomyelitis (bone infection), and in persons taking steroid therapy chronically.
Patients taking antiresorptive medications to reduce their risk of bone fracture also may rarely experience ONJ. Why some patients taking antiresorptive medications get ONJ is unknown. It may be due to a decrease in the bone’s ability to repair itself; a decrease in blood vessel formation; or possible effects of infection.
Patients taking medicines that are classified as bisphosphonates may develop osteonecrosis of the jaw (ONJ). While there is a very low risk of ONJ occurring in people taking any of these medications, the risk may be slightly higher in people who require invasive dental procedures such as a dental extraction or dental implant if they also take bisphosphonates.
The risk of developing ONJ also depends on the medical condition the bisphosphonate is being used to treat. Patients who receive intravenous (through a needle placed in a vein) bisphosphonates as part of their cancer treatment are at higher risk for ONJ than those who receive the much lower doses for osteoporosis treatment. Older age, diabetes, gum disease and smoking also raise ONJ risk.
There is no diagnostic test to determine if an individual patient is at increased risk for ONJ, but some factors are known to raise the risk in very rare circumstances. The condition itself is diagnosed only by the presence of exposed bone, lasting more than eight weeks. Patients typically complain of pain, which is often related to infection, soft tissue swelling, drainage, and exposed bone.
Most patients with osteoporosis who develop ONJ are treated conservatively with rinses, antibiotics, and oral analgesics. Studies have shown conservative treatment to be effective. There are case reports of the use of teriparatide in management of ONJ.
Rheumatologists are specialists in musculoskeletal disorders including osteoporosis and therefore are best qualified to review the risks and benefits of antiresorptive therapy for osteoporosis. They can also advise patients about the best treatment options available.
A health program of oral hygiene and regular dental care is the optimal approach for lowering osteonecrosis of the jaw risk. Patients should inform their dentists that they are taking potent antiresorptive therapy, such as alendronate (Fosamax), risedronate (Actonel and Atelvia), ibandronate (Boniva), zoledronic acid (Reclast) or denosumab (Prolia).
For instance, endodontic (root canal) treatment is preferred to dental extraction if the tooth can be saved. If dental extraction is needed, full mouth dental extractions or periodontal surgery should be avoided. (It may be better to assess healing by doing individual extractions.)
Patients with periodontal disease should consider non-surgical therapy before agreeing to surgical treatment. Many patients taking bisphosphonates may undergo dental implants without problems. Although some dentists recommend the use of blood tests to decide who is at risk, this practice is controversial due to a very limited evidence base and should not be used at this time. This is in agreement with current American Dental Association suggestions.
Those on oral bisphosphonates are at low risk for ONJ. If patients detect any mouth pain or problems, they should seek dental care right away. It is not necessary to stop bisphosphonate use before a dental procedure, but it may be best to delay starting the drug therapy until after a scheduled dental procedure.
Updated December 2021 by the American College of Rheumatology Committee on Communications and Marketing.
This information is provided for general education only. Individuals should consult a qualified health care provider for professional medical advice, diagnosis and treatment of a medical or health condition.