Zoledronic acid and bisphosphonate related osteonecrosis of the jaw

Zoledronic acid is the most potent bisphosphonate (BP) currently available for use in various clinical conditions. This increasing use of the high potency drug has led to an elevated incidence of a unique but well-documented oral adverse effect termed "bisphosphonate-related osteonecrosis of the jaws (BRONJ)". BRONJ, as a clinical entity, is classically described as a non-healing ulcer on the jaw bone (maxillae or mandible) in a patient with a history of BP use in the absence of radiotherapy. Initially, the aetiology of BRONJ was considered to be related to direct suppression of osteoclastic activity in the jaw bone. However, recent literature suggests that a host of factors are involved in the pathogenesis of this complex condition and a wide variation exists in its occurrence, mainly based on the potency of the BP used. BRONJ is specifically reported in jaw bones and zoledronic acid, due to its high potency is the most commonly implicated drug. A thorough knowledge of BRONJ is important for a dental surgeon as it is essential for initial identification, prompt diagnosis and successful management of this unique condition. This chapter comprises an overview of BRONJ as a clinical entity, classification and staging, various etio-pathological theories, and general guidelines in management of zoledronic acid induced BRONJ