BIOACTIVE GLASS GRANULES AND POLYTETRAFLUOROETHYLENE MEMBRANE IN THE REPAIR OF BONE DEFECTS ADJACENT TO TITANIUM AND BIOACTIVE GLASS IMPLANTS

An experimental animal model was used to investigate the effect of bio active glass (BG) granules and nonresorbable polytetrafluoroethylene ( PTFE) membrane on the repair of cortical bone defects adjacent to tita nium and BG implants. Thirty-two Astra(R) (diameter 3.5 mm) dental imp lants were inserted bicortically and 42 conical BG implants (diameter 2.5-3.0 mm) monocortically, into fitted holes of rabbit tibia. Before implantation, a standardized bone defect was created by drilling an ex tra hole (diameter 3.0 mm) adjacent to each implant site. Twenty-eight defects were filled with BG granules (diameter 630-800 mu m) (BG grou p) and 28 defects were left empty but covered with PTFE membrane (PTFE group). No material was used in 18 control defects (control group). M orphometrical evaluation with a digital image analysis system was used to measure bone repair as percentages of the defect area on scanning electron microscopy (SEM) and light microscopy pictures. Bone-implant contact was measured as percentages of the thickness of the cortical b one. At 6 and 12 wk, bone repair in defects in connection with titaniu m implants was 23.2% and 36.6% in the BG group, 23.2% and 32.4% in the PTFE group, and 47.2% and 46.2% in control defects. Corresponding fig ures for BG implants were 33.2% and 40.1% in the BG group, 16.6% and 3 3.5% in the PTFE group, and 25.7% and 54.9% in control defects. BG gra nules and new bone together filled 82.7% and 68.5% of the defect area adjacent to titanium implants, a nd 75.9% a nd 74.4% of the defect adj acent to BG implants at 6 a nd 12 wk, respectively. Better bone-implan t contact was achieved at the defect side with BG than titanium implan ts (77.0% versus 45.0% at 12 wk). The results indicate that BG granule s are useful in treatment of bone defects adjacent to dental implants. BG coating of the implant seems to improve osseointegration in the de fect area.