STABILITY OF ZIRCONIA-TOUGHENED BIOACTIVE GLASS-CERAMICS - INVIVO STUDY USING DOGS

The strength of zirconia-toughened glass-ceramic composite was measured after subcutaneous implantation in dogs. The bending strength was not degraded at all 12 weeks after implantation. Scanning electron microscopy revealed that the composite reacted very slowly with body fluid. The thickness of the reaction layer was about 10 mum in depth after 12 weeks, and was less than the critical flaw size (approximately 30 mum) estimated from the bending strength and the fracture toughness. We found that the zirconia-toughened glass-ceramic composite exhibited high strength in living body fluid for a long period.