Increased incidence of osteonecrosis of the jaw after tooth extraction in patients treated with bisphosphonates: a cohort study

This study estimated the cumulative incidence and risk ratio for osteonecrosis of the jaw (ONJ) after tooth extraction in patients with and without administration of bisphosphonates (BP) and identified potential risk factors for bisphosphonate-induced osteonecrosis of the jaw (BIONJ). A cohort study was conducted in all patients undergoing tooth extraction at a university hospital in Japan from April 2006 to June 2009. Of 3216 patients, 126 had BP administration, of whom 5(3.9%, 95% confidence interval (CI): 1.2-9.2) developed ONJ, versus 1 (0.032%, 95% CI: 0.00081-0.18) among 3090 patients without BP administration. BP administration was associated with the development of ONJ after tooth extraction, with an unadjusted risk ratio of 122.6 (95% CI: 14.4-1041.8). When stratified by age and route of BP administration, the risk ratio for ONJ patients aged 65 years or older with intravenous BP administration compared to those without was 200.2 (95% CI: 23.8-1679.4, P < 0.001). Patients receiving BP showed a significant association between the incidence of BIONJ and alveolar bone loss score. The risk of ONJ is higher in patients with than without BP administration, particularly intravenous administration. Severe periodontitis might be a risk factor for BIONJ.