Bone-bonding ability of P2O5-free CaO.SiO2 glasses.
An apatite- and wollastonite-containing glass-ceramic (A.W-GC) has been reported to form a tight bond with living bone through an apatite layer formed on its surface. This layer is considered to be formed by dissolution of Ca2+ and HSiO3- ions from the glass-ceramic into the surrounding body fluids. In order to confirm this proposed mechanism for the surface reaction of A.W-GC, three kinds of glass in the systems CaO-SiO2, CaO-SiO2-CaF2, and CaO-SiO2-P2O5 were implanted into the tibiae of rabbits for 3 or 8 weeks. Contact microradiography and SEM-EPMA showed that all three kinds of glass formed a Ca,P-rich layer in combination with a Si-rich layer on their surfaces within 3 weeks and formed a direct bond with bone via these layers. The detaching test, performed 8 weeks after implantation, showed that the loads required to detach the implants from the bone were almost equal for the phosphorus-free and the phosphorus-containing glasses. It was concluded that even P2O5-free CaO.SiO2 glass formed a Ca,P-rich layer on its surface and bonded tightly with living bone. If glasses and glass-ceramics release at least Ca2+ and HSiO3- ions, this would be sufficient for them to form the Ca,P-rich layer on their surfaces in vivo, enabling them to bond directly with bone.
Ohura
K
K
Department of Orthopaedic Surgery, Faculty of Medicine, Kyoto University, Japan.
Nakamura
T
T
Yamamuro
T
T
Kokubo
T
T
Ebisawa
Y
Y
Kotoura
Y
Y
Oka
M
M
D000818:Animals; D001031:Apatites / Q000737:chemistry*; D001842:Bone and Bones / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry*; D017610:Calcium Compounds; D005898:Glass / Q000737:chemistry*; D008297:Male; D010758:Phosphorus / Q000737:chemistry; D019736:Prostheses and Implants; D011817:Rabbits; D017640:Silicates; D012824:Silicic Acid / Q000737:chemistry*; D013499:Surface Properties; D013977:Tibia / Q000378:metabolism
D001031:Apatites; D017610:Calcium Compounds; D017640:Silicates; D012824:Silicic Acid; D010758:Phosphorus; C031293:calcium silicate; D002118:Calcium