**4.2 Inflammation or infection**

In the pathogenesis of medication-related osteonecrosis, inflammation plays a significant role development. Advanced periodontal disease and tooth extraction are one of the main triggers for occurrence of necrosis. Pathohistological analysis of bone parts, which are affected with osteonecrosis, decontamination with various bacteria is present, especially *Actinomyces* species in 70–100% of cases [34]. The main role in development of MRONJ has bacterial decontamination [35, 36]. Bisphosphonates have synergistic effect with bacteria because they increase the possibility of bacterial adhesion to hydroxyapatite found in the bone, resulting in the invasion of microorganisms into the bone itself afterwards the bone loses blood supply, becomes avascular and necrotic.
