ONJ in two dental practice-based research network regions

The incidence of osteonecrosis of the jaw (ONJ) in the population is low, but specifics are unknown. Potential risk factors include bisphosphonate treatment, steroid treatment, osteoporosis, and head/neck radiation. This Dental Practice-Based Research Network study estimated ONJ incidence and odds ratios from bisphosphonate exposure and other risk factors using a key word search and manual chart reviews of electronic records for adults aged ≥ 35 yrs enrolled during 1995-2006 in two large health-care organizations. We found 16 ONJ cases among 572,606 cohort members; seven additional cases were identified through dental plan resources. Among 23 cases (0.63 per 100,000 patient years), 20 (87%) had at least one risk factor, and six (26%) had received oral bisphosphonates. Patients with oral bisphosphonates were 15.5 (CI, 6.0-38.7) more likely to have ONJ than non-exposed patients; however, the sparse number of ONJ cases limits firm conclusions and suggests that the absolute risks for ONJ from oral bisphosphonates is low.