Histochemical observation of bony reversal lines in bisphosphonate-related osteonecrosis of the jaw

Abstract

To contrast the pattern of bony reversal linesin bisphosphonate osteonecrosis of the jaw with infected osteomyelitis derived acute osteonecrosis of the jaw. This study investigated the histochemical characteristics of reversal lines in 50 cases of BP-related osteonecrosis of the jaw (BRONJ) compared with non-BP-involved bones in 20 cases of chronic osteomyelitis of the jaws. Necrotic bones were stained by using the toluidine blue, Safranin O, Giemsa, van Gieson, and Masson's trichrome staining methods. All BP-involved bones in BRONJ were distinguishable from non-BP-involved bones in chronic osteomyelitis of the jaws by multiple thick, irregular, reversal lines, which were strongly stained with toluidine blue, Safranin O, and Giemsa solution. The reversal lines of BP-involved bones (average 31.2±10.85μm) were thicker than those of osteomyelitic bones (average 11.1±3.76μm), and they were closely associated with immature bony matrices containing collagenous materials positive for van Gieson and Masson's trichrome staining with statistical significance (P=.0212 in t test statistics). The immature reversal lines of BP-involved bones continuously appeared as thick non-birefringence lines between lamellate structures as observed under a polarizing microscope, whereas the reversal lines of non-BP-involved bones were gradually thinned as their mineralization advanced. BP-involved bones had immature bony matrices outlined by thick reversal lines, which might be crucial to rapid osteonecrosis of BRONJ and also could be hallmarks for the differential diagnosis of BRONJ from chronic osteomyelitis of the jaws.