Objetive:

Osteonecrosis of the jaw (ONJ) is a recently reported disease whose origin and development are unknown, although prolonged bisphosphonate treatment has been attributed, among other causes. While ONJ is a localized condition, the action of bisphosphonates is widespread and affects all bones. No studies show the general bone status of patients with ONJ. Our study examines the general condition in patients with ONJ using quantitative measurements and qualitative estimates of bone by means of bone mineral density (BMD) and trabecular bone score (TBS) and ultrasound parameters in the calcaneus (QUS), along with other diseases and the taking of drugs (especially bisphosphonates) in patients with ONJ who may be involved in the pathogenesis.

Material and method:

Observational and cross-sectional study of cases and controls, conducted in 304 patients of both sexes, in which the case group (group I) was formed by 24 patients who had suffered ONJ. The control group (group II) contained 280 patients who did not present ONJ and who received bisphosphonates over at least 5 years for various reasons. All of them underwent bone densitometry (DXA, Hologic 4500 Discovery®) in the lumbar spine and proximal femur. In addition, TBS measurements were made in the lumbar spine, as well as ultrasound parameters in the calcaneus (Hologic, Sahara®) in the dominant foot (QUS).

Results:

Patients suffering ONJ presented greater comorbidity than controls, with a higher prevalence of diabetes mellitus, cancer, rheumatoid arthritis, hyperthyroidism, heart disease, arrhythmias, heart failure and hypercholesterolemia. Therefore, the consumption of corticosteroids, (oral and inhaled), anticoagulants, hypnotics, bisphosphonates i.v. (zoledronate), and antineoplastic chemotherapy was also higher among patients with ONJ than control patients. However, among the patients with ONJ the percentage taking oral bisphosphonates was lower. Densitometric values (BMD measured in lumbar spine L2-L4, femoral neck and total hip) were higher in patients with ONJ compared to those in controls. The TBS showed no statistically significant differences between the two groups, and the ultrasound showed higher values of QUI and SOS in patients with ONJ than in controls. The prevalence of fragility fractures was similar in both groups.

Conclusions:

Patients with ONJ in our study presented greater comorbidity and a higher consumption of drugs than the patients in the control group, except for oral bisphosphonates. On the other hand, both BMD and ultrasound showed higher values in patients with ONJ than in controls. If we consider DXA as a technique for measuring the amount of bone mass, and TBS and calcaneal ultrasound estimating qualitative aspects of bone, we could assume that neither bone quantity nor quality in general seems to be affected in ONJ, and that its etiopathogenic mechanism is probably another. Oral bisphosphonates do not appear to be among the drugs involved in ONJ’s origin and development, but the most potent and intravenously administered bisphosphonates are, although they cannot be considered independently of the underlying disease for which they are administered.

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