Background: Osteonecrosis of the jaw (ONJ) is one of the complication of bisphosphonate (BP). Despite being a major risk factor for ONJ, tooth extraction cannot explain all cases of ONJ. However, disease that induce inflammation in the jawbone, such as pulp and periapical disease is underestimated, and studies suggesting relationship are arising. This necessitates the determination of the relationship between ONJ and inflammatory disease, which would contribute to the understanding and treatment of ONJ.Methods: We analyzed the relationship between ONJ and pulp and periapical disease, and caries in women aged over 50 years who were administered BP for over 1 year from 2010 to 2015, based on a nationwide cohort study. ONJ, pulp and periapical disease, and caries were defined according to the Korean Standard Classification of Diseases and Causes of Death-7 and claims data. ONJ was operationally defined into definite ONJ and possible ONJ because of the ambiguity of population-based ONJ diagnosis.Results: Pulp and periapical disease significantly increased ONJ development [hazard ratio 2.21 (95% CI 1.40-3.48) and 2.22 (95% CI 1.65-2.98) in definite ONJ and possible ONJ, respectively]. Additionally, the risk of ONJ development increased when caries addition to pulp and periapical disease [hazard ratio 2.28 (95% 1.50-3.47) and 2.05 (95% 1.55-2.70) in definite ONJ and possible ONJ, respectively]. Nonetheless, those in the caries were not significant. Root canal treatment in most cases did not increase ONJ development significantly, but the pulp and periapical disease or caries significantly increased possible ONJ development [hazard ratio 2.17 (95% CI 1.04-4.52)].Conclusions: It is necessary to focus on pulp and periapical disease resulting in inflammation as a major risk factor for ONJ. Future studies should determine the role of low-grade inflammation for ONJ on other ONJ-inducing drugs as anti-resorptive agents.
