Bone bonding behavior of MgO-CaO-SiO2-P2O5-CaF2 glass (mother glass of A · W‐glass‐ceramics)

Abstract

In this study, it was found that a CaP layer and a Si layer were formed on the interface of the mother glass of apatite–wollastonite containing glass-ceramics (designated AW) and bone tissue. The dissolution of Si, Ca, and P from glass (MgOCaOSiO₂P₂O₅CaF₂) is necessary to form a chemical film (a Si layer and a CaP layer). The three kinds of glasses used were (1) a mirror surface of the mother glass (MgO 4.6, CaO 44.9, SiO₂ 34.2, P₂O₅ 16.3, CaF 0.5 weight ratio) of AW (designated GAW (mirror)), (2) an abraded surface of GAW (designated GAW (#2000)), (3) a mirror surface SiO₂ glass (designated GSi, 100%SiO₂). The glass plates (15 mm × 10 mm × 2 mm) were implanted into the metaphysis of tibia of mature male rabbits for 10 and 25 weeks. The failure load, when an implant detached from the bone or when the bone itself broke, was measured by a detaching test and the interface of glass/bone was observed by SEM-EPMA. Failure loads in GSi, GAW (mirror), and GAW (#2000) 10 weeks after implantation were 0.18 ± 0.24, 3.06 ± 1.29, and 2.94 ± 1.77 kg, respectively. Those in GSi, GAW (mirror), and GAW (#2000) 25 weeks after implantation were 1.30 ± 1.18, 3.88 ± 1.06, and 3.55 ± 1.51, respectively. The failure loads in GSi vs. GAW (mirror) and those in GSi vs. GAW (#2000) differed significantly (P < 0.01). There were no significant differences in the failure load according to the surface roughness of GAW. As shown by SEM-EPMA observation, a Si layer next to G was adjacent to a CaP layer next to the bone. The chemical film showed no increase in thickness as time passed. A CaP layer did not form on the interface of SiG and bone.