Bone formation in rabbit cancellous bone defects filled with bioactive glass granules

We examined new bone formation after filling cancellous bone defects with bioactive glass (BG) in granular form. Cylindrical defects in the trochanter area of 18 rabbit femora were filled with BG granules (diameter 600-830 microns) and compared with similar defects filled with morcellized autogenous bone. New bone formation and surface reaction of BG particles were evaluated by light microscopy, histomorphometry, and scanning electron microscopy. The chemical profile at the bone- material interface was studied by energy dispersive x-ray analysis (EDXA). In the BG group, 41, 32, and 38 percent of the defects were filled with new bone after 3, 6, and 12 weeks, respectively. The corresponding figures for the autogenous bone group were 36, 29, and 34 percent. The thickness of the reaction layer on the glass surface increased from 82 to 163 microns during the observation periods. An intimate contact without intervening soft tissue between new bone lamellae and BG granules was a constant finding. EDXA showed a chemical continuum between the granules and the new bone. No adverse reactions related to BG were observed. BG is a promising material for filling cancellous bone defects.