What is the Risk of Developing Osteonecrosis Following Dental Extractions for Patients on Denosumab for Osteoporosis?

Purpose: Osteonecrosis of the jaws (ONJ) occurs in patients on antiresorptive drugs for osteoporosis with the risk with oral bisphosphonates being known to be of the order of 0.1 to 0.3% while the risk for patients on denosumab for osteoporosis is not known. The aim of this study was to determine the risk of developing ONJ in a consecutive series of patients on denosumab for osteoporosis having dental extractions.

Material And Methods: A prospective cohort study of patients on denosumab for osteoporosis having dental extractions in the period January 1, 2017 and June 30, 2021 were compared to a control group not on antiresorptives. Detailed demographic records including length of time on antiresorptives and CTX values were obtained. Comparison to further define risk factors was made between those patients developing ONJ to those who didn't.

Results: The treatment group included 427 patients who were on denosumab for osteoporosis; they collectively underwent 561 episodes of dental treatment involving extractions for a total of 1081 extractions, with 10 developing ONJ (risk 2.3%). The control group consisted of 299 patients who were not taking denosumab; they collectively underwent 315 episodes of dental treatment for a total of 669 extractions, and none of them developed ONJ. There were significant differences in age and sex, but not medical comorbidities between the treatment and control groups. Within the treatment group, there were no significant differences in any of these characteristics between those who did, and those who didn't, develop ONJ. Within the treatment group, the number of extractions modified the risk of developing ONJ (odds ratio, 1.35; confidence interval, 1.1-1.7). Of the 76 patients who had extractions between 6 and 7 months after the last denosumab injection, none developed ONJ.

Conclusions: The risk of ONJ in patients on denosumab for osteoporosis is a magnitude greater than for patients on the oral bisphosphonates 2.3% v 0 - 0.3%, which is 7.7 times more likely. Number of extractions and early resumption of the next dose of denosumab increases the risk of ONJ.