title: Stimulatory effect of zinc-releasing calcium phosphate implant on bone formation in rabbit femora.
abstract: Although hydroxyapatite (HAP) and tricalcium phosphate (TCP) are currently used as bone graft substitutes or coatings on metallic prostheses because of their excellent biocompatibility and osteoconductivity, they do not stimulate bone formation or inhibit bone resorption. Zinc, an essential trace element in many animals, has a direct specific proliferative effect on osteoblastic cells and has a potent and selective inhibitory effect on osteoclastic bone resorption in vitro. Therefore, zinc-containing beta-tricalcium phosphate (ZnTCP) ceramics and composite ceramics of ZnTCP and HAP (ZnTCP/HAP) were implanted in the femora of New Zealand White rabbits for 4 weeks to promote bone formation. The implants were sintered ceramics with zinc contents of 0 (control), 0.063, 0.316 and 0.633 wt %. Histological and histomorphometrical investigation of the undecalcified sections revealed an increase by 51% (p =.0509) in the area of newly formed bone around the ZnTCP/HAP implants of 0. 316 Zn wt % compared with the control. Plasma zinc concentration was unchanged. An increased bone resorption on the endosteal surface was observed when ZnTCP and ZnTCP/HAP of 0.633 Zn wt % were implanted. To promote bone formation, the optimum zinc content of the calcium phosphate ceramics was therefore 0.316 wt %.
authors.affiliation: Department of Orthopedic Surgery, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba-shi, Ibaraki 305-8571, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kawamura
authors.forename: A
authors.initials: A
authors.lastname: Ito
authors.forename: S
authors.initials: S
authors.lastname: Miyakawa
authors.forename: P
authors.initials: P
authors.lastname: Layrolle
authors.forename: K
authors.initials: K
authors.lastname: Ojima
authors.forename: N
authors.initials: N
authors.lastname: Ichinose
authors.forename: T
authors.initials: T
authors.lastname: Tateishi
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D016723:Bone Remodeling; D018786:Bone Substitutes; D002130:Calcium Phosphates; D005269:Femur; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D011817:Rabbits; D015032:Zinc
chemical_list: D001672:Biocompatible Materials; D018786:Bone Substitutes; D002130:Calcium Phosphates; D015032:Zinc