title: Ultrastructural study of the A-W GC-bone interface after long-term implantation in rat and human bone.
abstract: The interface between apatite- and wollastonite-containing glass-ceramic (A-W GC) and bone after long-term implantation was studied by scanning and transmission electron microscopy (SEM and TEM) using rat and human specimens. First, particles of A-W GC (100-220 microns in diameter) were implanted into rat tibiae, and specimens were prepared for observation at 24, 48, 72, and 96 weeks after the operation. These long-term specimens showed an A-W GC-bone interface different from that at an earlier stage, which was investigated in our previous studies. SEM showed that the Ca-P-rich layer was wider, suggesting that leaching of ions from the A-W GC had continued even after bonding with bone. In some regions, the material particles were evidently replaced by the bone. TEM showed that the intervening apatite layer had become indistinct, and that A-W GC had intermingled with bone at the interface. In some regions, the surface of the A-W GC was degraded. These findings suggest that the surface region of A-W GC is slowly replaced by bone. Second, a human bone specimen, which included A-W GC particles (300-700 microns in diameter) implanted as a bone filler for about 75 weeks was harvested and investigated. Excellent A-W GC-bone bonding was observed, and the ultrastructure of the interface was similar to that in rats after long-term implantation. This finding demonstrated that A-W GC possibly worked in human bone in the same way as in rat bone, showing excellent bioactivity.
authors.affiliation: Department of Orthopedic Surgery, Faculty of Medicine, Kyoto University, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Neo
authors.forename: T
authors.initials: T
authors.lastname: Nakamura
authors.forename: C
authors.initials: C
authors.lastname: Ohtsuki
authors.forename: R
authors.initials: R
authors.lastname: Kasai
authors.forename: T
authors.initials: T
authors.lastname: Kokubo
authors.forename: T
authors.initials: T
authors.lastname: Yamamuro
mesh_terms: D000328:Adult; D000818:Animals; D001031:Apatites; D001672:Biocompatible Materials; D016723:Bone Remodeling; D001842:Bone and Bones / Q000648:ultrastructure*; D002130:Calcium Phosphates / Q000032:analysis; D002516:Ceramics; D005269:Femur / Q000601:surgery / Q000648:ultrastructure; D005357:Fibrous Dysplasia of Bone / Q000473:pathology / Q000601:surgery; D006801:Humans; D008297:Male; D008422:Materials Testing; D008852:Microradiography; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D016348:Osseointegration; D019736:Prostheses and Implants; D051381:Rats; D017208:Rats, Wistar; D012824:Silicic Acid
chemical_list: D001031:Apatites; D001672:Biocompatible Materials; D002130:Calcium Phosphates; C485828:alpha-tricalcium phosphate; C077777:apatite-wollastonite-containing glass ceramic; C485830:tetracalcium phosphate; D012824:Silicic Acid; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous