Medication-Related Osteonecrosis of the Jaw (MRONJ) is a serious condition characterized by the progressive destruction and death of bone tissue in the jaw. This condition is observed in patients who are currently receiving or have previously received certain medications, such as antiresorptive or antiangiogenic agents [1, 5, 2.1]. These medications are often prescribed to manage conditions like osteoporosis, osteopenia, or various cancers that involve bone. Staging is a classification system used by healthcare providers to describe the severity and extent of MRONJ, guiding its management.
Why Staging Matters
Staging provides a standardized framework for understanding MRONJ progression and predicting prognosis [4.4]. It helps healthcare professionals select appropriate treatment strategies [2.2].
The staging system facilitates clear communication among the medical team, ensuring a shared understanding of the disease’s status [4.4]. For patients, staging offers valuable information about their condition, helping them understand what to expect and participate more actively in treatment decisions [4.4]. Staging systems, particularly those developed by organizations like the American Association of Oral and Maxillofacial Surgeons (AAOMS), provide standardized criteria for classification, ensuring consistency in diagnosis and management [2.2, 3.2, 4.4].
The Stages of MRONJ Explained
The AAOMS staging system categorizes MRONJ into stages.
Stage 0
Stage 0 represents a preclinical phase with no visible exposed bone, but patients may experience non-specific symptoms [1.1, 2.2, 4.4]. These can include unexplained tooth pain, a dull ache in the jaw that might radiate to the temporomandibular joint, or altered nerve sensations [2.2, 4.4]. Radiographic changes, such as bone sclerosis or thickening of the lamina dura, may also be present without overt bone exposure [3.3, 4.4]. This stage can be a precursor to more advanced MRONJ [4.4].
Stage 1
Stage 1 is characterized by exposed and necrotic bone in the jaw, or a fistula that probes to the bone, without signs of infection or inflammation [1.1, 2.2, 4.4]. Patients in this stage are asymptomatic despite the visible bone exposure [1.1, 2.2, 4.4]. The surrounding soft tissue remains intact [3.3].
Stage 2
In Stage 2, exposed and necrotic bone is present with clear evidence of infection and inflammation [1.1, 2.2, 4.4]. Individuals are symptomatic, often experiencing pain, redness, and swelling in the affected area [2.2, 3.3]. Pus discharge and foul breath can also be present, indicating a localized infection [3.3].
Stage 3
Stage 3 represents the most advanced form of MRONJ, featuring extensive exposed and necrotic bone, persistent infection, and additional severe complications [1.1, 2.2, 4.4]. These complications can include pathologic fractures of the jaw, extraoral fistulae (openings outside the mouth), or communication between the oral cavity and the maxillary sinus or nasal cavity [2.2, 4.4]. Bone necrosis may extend beyond the alveolar bone, potentially involving areas like the inferior border of the mandible or the zygoma in the maxilla [2.2, 4.4].
How Staging is Determined
Determining the stage of MRONJ involves several key components. A comprehensive clinical examination of the oral cavity and jaw is a primary step. A healthcare professional inspects for visible exposed bone, swelling, or signs of infection [3.3, 5.5]. The presence of exposed bone or a fistula that can be probed to bone, persisting for more than eight weeks, is a defining clinical criterion for MRONJ [1, 2.1, 3.3].
A detailed review of the patient’s medical history is also reviewed, with particular attention to current or previous medication use [3.3]. This includes identifying exposure to antiresorptive drugs like bisphosphonates or denosumab, as well as anti-angiogenic agents, which are commonly associated with MRONJ [1, 2.1, 3.3]. It is also important to rule out a history of radiation therapy or metastatic disease to the jaws, as these can cause similar bone conditions [1, 2.1].
Imaging studies play a supporting role in assessing the extent of bone involvement, though often not sufficient for definitive staging without clinical correlation [4.4, 5.5]. Panoramic radiographs are frequently used as an initial tool to provide a broad view of the jaw structures, showing potential signs like osteolysis, osteosclerosis, or thickened lamina dura [1.5, 2.2, 5.5]. Cone-beam computed tomography (CBCT) or conventional CT scans offer more detailed three-dimensional views, particularly helpful in advanced stages to delineate the disease’s full extent, including nerve or sinus involvement [1.5, 2.2]. An oral and maxillofacial surgeon or a dentist experienced in MRONJ combines these findings to assign the appropriate stage [3.3].
Treating MRONJ Based on Stage
Treatment strategies for MRONJ are tailored to the specific stage of the disease, with interventions becoming more aggressive as the condition advances.
Stage 0 Treatment
For patients with Stage 0 MRONJ, management focuses on non-surgical approaches [2.2, 3.3]. This involves systemic management, including pain medication and potentially antibiotic rinses to control oral bacteria [2.2, 3.3]. Close monitoring of the patient’s symptoms and oral health is also an aspect of care at this initial stage [2.2].
Stage 1 Treatment
Stage 1 MRONJ involves conservative management aimed at preventing progression and maintaining oral hygiene [2.2, 3.3]. This includes meticulous oral hygiene practices and the use of antibiotics as needed, particularly if there is a risk of infection [2.2, 3.3]. While surgical intervention is avoided, localized debridement of mobile bony sequestra (loose pieces of dead bone) may be considered to facilitate soft tissue healing [1.6].
Stage 2 Treatment
For individuals with Stage 2 MRONJ, treatment involves more aggressive medical management to address the exposed bone and accompanying infection [2.2, 3.3]. This includes systemic antibiotics and pain control [2.2, 3.3]. Minor surgical debridement of the exposed necrotic bone may also be performed [2.2, 3.3].
Stage 3 Treatment
Stage 3 MRONJ necessitates more extensive surgical intervention due to widespread bone necrosis and associated complications [2.2, 3.3]. This can involve resection of necrotic bone, which may require reconstructive procedures to restore jaw function and appearance [2.2, 3.3]. Long-term medical management, including ongoing antibiotic therapy and pain control, is part of the care plan for these advanced cases [2.2, 3.3]. Throughout all stages, treatment is individualized, reflecting the patient’s overall health and specific presentation, and involves a multidisciplinary team approach [2.2, 3.3].