Understanding Jaw Osteonercrosis – Avascular, Bisphosphonate-Related, and Osteoradionecrosis Explained: Narrative Review

Objective: This narrative review synthesizes current knowledge on Medication-Related Osteonecrosis of the Jaw (MRONJ), Osteoradionecrosis (ORN) and the newly emerging Avascular Osteonecrosis of the Jawbone (AON) due to corticosteroid use. It explores their etiopathogenesis and clinical features. Additional comparative analysis of these conditions was made to highlight their distinct and overlapping characteristics, aiding in their better understanding and differentiation. Materials and methods: A comprehensive literature search was performed using PubMed and Scopus databases. The final search was conducted on March 31, 2025. Search terms included: "osteonecrosis" AND "jaw". "mandible" AND "corticosteroid therapy". "medication-related osteonecrosis of the jaw". "osteoradionecrosis". Eligibility criteria Study design: Clinical studies (prospective or retrospective), case series, and systematic reviews. Language: English only. Population: Human patients with confirmed diagnoses of MRONJ, ORN, or corticosteroid-induced avascular osteonecrosis of the jaw. Interventions/Exposures: Use of bisphosphonates, denosumab, radiation therapy, or corticosteroid therapy. Outcomes: Diagnosis, pathophysiology, clinical manifestations, imaging, management, and treatment outcomes. Screening and selection: Two independent reviewers screened all titles and abstracts. Full-text review was conducted for potentially eligible studies. Discrepancies were resolved by consensus. No kappa statistics were calculated due to the narrative nature of this review. Included studies: A total of 46 studies met the inclusion criteria, comprising 32 clinical studies and 14 systematic reviews. These were analyzed to identify patterns in etiopathogenesis, clinical features, and comparative outcomes between MRONJ, ORN, and AON. Results: Despite differences in their pathogenesis, avascular osteonecrosis of the jaw due to corticosteroid use, MRONJ, and ORN exhibit similar clinical manifestations, including bone exposure, pain, and infection. Despite their similarities, attention should be given to fully understand their etiologic origin, as it dictates a different management strategy. Conclusion: The distinct origins of AON, MRONJ, and ORN converge on a common pathophysiological pathway: compromised vascular function leading to bone necrosis. This shared feature underscores the critical role of vascular health in maintaining bone integrity and facilitating repair processes. This literature review renders it important that future research should focus on developing targeted diagnostics and prevention protocols to optimize patient care and reduce morbidity.