Frontal bone defect repair with experimental glass-fiber-reinforced composite with bioactive glass granule coating

The aim of this preliminary study was to test the bioactive glass-coated fiber-reinforced composite (FRC) as a reconstruction material in the treatment of experimental defects in the frontal bone of rabbits.

FRC made of E-glass fiber and BisGMA-PMMA resin matrix system was used in the study. Pieces of nonpolymerized FRC were coated with particulate bioactive glass granules S53P4 (BAG), and then the FRC was polymerized and post-cured by heat in air to reduce the quantity of residual monomers, and to sterilize the material for the animal study. Two round defects (5 mm in diameter) were drilled in the upper bony walls of 12 NZW rabbits' frontal sinuses, and rectangular FRC plates were applied over the defects. In the control group, no FRC plates were used. The bone defect healing process was evaluated on histological sections at 3, 6, and 8 weeks, postoperatively. SEM-EDX analysis was used to determine reactive layers of bioactive glass granules.

The healing progressed from the fibroconnective tissue phase at 3 weeks to lamellar bone formation at 6 and 8 weeks. The difference in new bone formation between the implantation groups and control groups was not statistically significant, although in some animals the effect of the implant on bone healing was clearly positive. A moderate foreign body reaction was seen on the implant surface where BAG granules did not uniformly cover the implant's polymer matrix.

This study suggests that the tested FRC implant with bioactive glass coating provides an alternative for bone defect reconstruction. However, more research on this composite material and its biocompatibility is needed.