The influence of alendronate and tooth extraction on the incidence of osteonecrosis of the jaw among osteoporotic subjects.

Background: Although bisphosphonate-related osteonecrosis of the jaw (ONJ) develops mainly after tooth extractions (TEs), the strength of the association between them and how the existence of the disease among bisphosphonate (BP)-treated osteoporotic patients exposed to TE remain uncertain.
Methods: A nationwide retrospective cohort study investigated the influence of alendronate and TE on the development of ONJ.
Results: Incidence of ONJ following long-term alendronate therapy was 262/100,000 person-years, while no event developed in the control group on raloxifene. Overall prevalence of ONJ in osteoporotic subjects receiving alendronate was estimated at 0.34% which rose to 2.16% after TE. Multiple logistic regression analysis, adjusted for the potential confounders, showed TE (adjusted odds ratio, 9.60 [4.33-21.29]), drug duration exceeding 3 years (3.00 [1.33-6.76]), and concomitant rheumatoid arthritis (4.94 [1.64-14.90]) were independent predictors of ONJ.
Conclusions: This article strengthens the relationship between ONJ and BPs. Among osteoporotic patients exposed to alendronate, TE confers a 9.6-fold increased risk for ONJ and it should be performed with caution irrespective of drug duration.