Osteonecrosis of the jaw (ONJ) is a debilitating bone condition that affects the jaws and occurs as a result of reduced local blood supply to the bone. However, the literature involving ONJ -- especially as it relates to the consumption of bisphosphonates -- has been severely limited because most investigations cannot evaluate sufficient numbers of afflicted individuals to accurately determine the incidence of the disease and associated risk factors, according to the International and American Associations for Dental Research (IADR/AADR).
But two new studies published in the Journal of Dental Research (JDR, February 11, 2011) could lead to the development of better definitions for ONJ, the associations noted in a press release. These studies represent some of the largest published studies to date on ONJ patients.
In one, researchers from the University of Alabama School of Dentistry conducted a case-control study with three dental practice-based research networks to determine the risk associated with bisphosphonates and identify other ONJ risk factors, including dental diseases and procedures. They enrolled 191 ONJ cases and 573 controls from 119 dental practices and found that bisphosphonate use was "strongly associated" with ONJ with an odds ratio of 299.5 for intravenous use and 12.2 for oral use.
The second JDR paper involved a dental practice-based research network study that estimated ONJ incidence and odds ratios from bisphosphonate exposure and other risk factors using patients' electronic records.
Researchers from the Kaiser Permanente Center for Health Research identified 572,606 health plan members; of those patients, about 25,000 had a diagnosis or procedure code that suggested a necrotic bone lesion, including inflammatory jaw condition, cyst of bone, aseptic necrosis of the bone, and open wound of the jaw.
In analyzing these members' electronic medical records, the researchers identified 73 suspected ONJ cases, of which 16 were later confirmed by manual chart review. An additional seven cases were identified through oral surgeons or the Peer Review Committee for a total of 23 confirmed ONJ cases.
Patients with oral bisphosphonates were 15.5 times more likely to have ONJ than nonexposed patients, the researchers noted. However, the number of ONJ cases limits firm conclusions and suggests that absolute risk of developing ONJ from oral bisphosphonates is low, they added.
"ONJ represents a challenging clinical dilemma affecting dental and cancer patients, and communities at many levels of dentistry, notably oral/maxillofacial surgery and oral oncology, are called upon to manage these cases," stated JDR Editor-in-Chief William Giannobile, DDS, DMSc. "The work underscores important clinical implications that will be of value to not only the IADR and AADR communities, but especially practicing clinicians."
