Osteonecrosis of the jaw in Sweden associated with the oral use of bisphosphonate.

To estimate the incidence of bisphosphonate (BP)-related osteonecrosis of the jaw (BRONJ) associated with the use of oral BPs and osteonecrosis of the jaw (ONJ) not associated with current or previous medication with a BP or radiotherapy to the head and neck region (background ONJ) in Sweden. A survey was sent to all oral and maxillofacial surgery clinics and hospital dental clinics in Sweden. They were requested to report all new cases of BRONJ and background ONJ during 2007 and 2008. The response rate was 61%. The oral BRONJ incidence for patients aged 45 years or older was 67 cases/100,000 patient-years of BP medication in 2007 (1 case/1,500 patient-years). In 2008, 69 cases/100,000 patient-years (1 case/1,445 patient-years) were reported. The mean age at the development of oral BRONJ was 76.5 ± 10.8 years (median age 79, range 49 to 96) for 2007 and 79.8 ± 7.6 years (median 79, range 67 to 94) for 2008. Women were primarily affected (22 of 26 in 2007 and 25 of 29 in 2008). The incidence of background ONJ was low: 0.14 and 0.09/100,000 person-years for those aged 45 years or older in 2007 and 2008, respectively (3 cases in 2007 and 2 in 2008). The BRONJ incidence has been estimated to be more than 100-fold greater than the incidence of background ONJ. However, an average Swedish dental practice (1,234 patients) will only encounter 1 patient with new oral BRONJ every 62 nd year.