Bisphosphonate related osteonecrosis of the jaws: clinico-pathological investigation and histomorphometric analysis

Objectives. Clinico-pathological evaluation of bisphosphonate (BP)-related osteonecrosis of jaws, comparison between oral (PO) and intravenous (IV) BPs and histomorphometric analysis of associated actinomyces. Study design. Retrospective clinical and histomorphometric analysis. Data on background, clinical, treatment and follow-up were analyzed. Actinomyces colonies were identified by typical filamentous colony morphology, Gram, and PAS stains. Colony density and relative colony surface area were measured. Results. Fifty-two patients were included, 37 (71.2%) IV, 15 (28.8%) PO BPs. with a mean duration of 2.33 and, 4.33 years respectively. One hundred percent of cases exhibited actinomyces colonization. The relative colony surface area was significantly higher in PO treatment (P = .024), with no differences in density, healing time or antibiotic treatment periods. High frequency of diabetes mellitus (60% PO cases) and corticosteroid treatment (25% of cases) were recorded. Conclusion. Infection with actinomyces is a common denominator in BP-related osteonecrosis of the jaws (BRONJ), regardless of administration route. Diabetes and corticosteroid treatment seem to be important contributing factors for BRONJ.