Medication-Related Osteonecrosis of the Jaw (MRONJ) is an uncommon but serious condition defined by exposed bone in the mouth that fails to heal for more than eight weeks. This complication arises in people taking or who have previously taken certain medications. It often occurs after a minor jaw injury, such as a tooth extraction, where the bone cannot properly repair itself.
Associated Medications and Underlying Conditions
The medications most frequently linked to MRONJ fall into a category known as antiresorptive agents. These drugs function by slowing the natural process of bone breakdown, which is useful in treating certain medical conditions. This category includes two main classes: bisphosphonates and RANK ligand inhibitors. Bisphosphonates are widely prescribed for osteoporosis, with common brand names including Fosamax, Boniva, and the intravenous drug Reclast. They are also used in higher doses to manage bone complications from cancers like multiple myeloma and solid tumors with bone metastases.
RANK ligand inhibitors, such as Prolia and Xgeva, represent another class of antiresorptive drugs. Denosumab, the active ingredient, is a monoclonal antibody that disrupts the cells responsible for bone resorption. These medications are used to treat osteoporosis and to prevent skeletal-related events in patients with bone cancer. While less common, another class of drugs called antiangiogenic agents, which interfere with the formation of new blood vessels to restrict tumor growth, has also been associated with MRONJ.
Dental Risk Factors and Triggers
While specific medications create a predisposition for MRONJ, the condition is often initiated by a triggering event, most commonly an invasive dental procedure. Other procedures that involve direct manipulation of the jawbone, such as the placement of dental implants and other oral surgeries, also carry a significant risk.
In contrast, routine dental work that does not disturb the bone is considered low-risk. This includes procedures like professional cleanings, fillings for cavities, and standard root canal therapy. However, several other factors can elevate a person’s risk. The duration of medication use is a notable consideration; taking oral bisphosphonates for more than four years can increase susceptibility. Co-existing medical conditions like diabetes, as well as lifestyle choices such as smoking and poor oral hygiene, are also recognized as contributing risk factors that can compound the effects of the medication.
Preventative Strategies in Dentistry
For individuals identified as being at risk for MRONJ, proactive preventative measures are a primary focus in dental care. A comprehensive dental examination is strongly recommended before a patient begins taking an associated medication. This allows the dental team to identify and address any potential sources of infection or issues that might later require invasive procedures. The goal is to complete any necessary extractions or bone-related surgeries before the drug therapy starts, giving the jaw ample time to heal.
Effective communication between the patient, their dentist, and the prescribing physician is fundamental to managing risk. Maintaining excellent oral hygiene, including regular dental check-ups, is a continuous strategy to prevent dental diseases that could lead to the need for extractions. The idea of a “drug holiday,” or temporarily stopping the medication before a dental procedure, has been discussed. However, this is a complex and controversial topic, as the long half-life of some drugs means they remain in the skeletal system for years. Any decision regarding a drug holiday must be made in close consultation with the prescribing physician.
Symptoms and Management of an MRONJ Diagnosis
Symptoms of MRONJ can include pain, swelling of the surrounding soft tissues, signs of infection like pus or drainage, and numbness in the jaw. The management approach is often guided by the stage of the condition, which is used to classify its severity.
For early stages (Stage 1), where the exposed bone is present but there are no symptoms of infection, treatment is conservative. This often involves the use of antimicrobial mouth rinses, such as chlorhexidine, to keep the area clean and manage the bacterial load. If infection and pain develop (Stage 2), systemic antibiotics and pain-control medications are added to the regimen. Surgical intervention to remove the area of necrotic bone is reserved for more advanced cases (Stage 3) or for patients who do not respond to conservative management.