title: Apatite Formation and Biocompatibility of a Low Young's Modulus Ti-Nb-Sn Alloy Treated with Anodic Oxidation and Hot Water.
abstract: Ti-6Al-4V alloy is widely prevalent as a material for orthopaedic implants because of its good corrosion resistance and biocompatibility. However, the discrepancy in Young's modulus between metal prosthesis and human cortical bone sometimes induces clinical problems, thigh pain and bone atrophy due to stress shielding. We designed a Ti-Nb-Sn alloy with a low Young's modulus to address problems of stress disproportion. In this study, we assessed effects of anodic oxidation with or without hot water treatment on the bone-bonding characteristics of a Ti-Nb-Sn alloy. We examined surface analyses and apatite formation by SEM micrographs, XPS and XRD analyses. We also evaluated biocompatibility in experimental animal models by measuring failure loads with a pull-out test and by quantitative histomorphometric analyses. By SEM, abundant apatite formation was observed on the surface of Ti-Nb-Sn alloy discs treated with anodic oxidation and hot water after incubation in Hank's solution. A strong peak of apatite formation was detected on the surface using XRD analyses. XPS analysis revealed an increase of the H2O fraction in O 1s XPS. Results of the pull-out test showed that the failure loads of Ti-Nb-Sn alloy rods treated with anodic oxidation and hot water was greater than those of untreated rods. Quantitative histomorphometric analyses indicated that anodic oxidation and hot water treatment induced higher new bone formation around the rods. Our findings indicate that Ti-Nb-Sn alloy treated with anodic oxidation and hot water showed greater capacity for apatite formation, stronger bone bonding and higher biocompatibility for osteosynthesis. Ti-Nb-Sn alloy treated with anodic oxidation and hot water treatment is a promising material for orthopaedic implants enabling higher osteosynthesis and lower stress disproportion.
authors.affiliation: Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Hidetatsu
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Mori
authors.affiliation: Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Noro
authors.affiliation: Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kogure
authors.affiliation: Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kamimura
authors.affiliation: Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Norikazu
authors.initials: N
authors.lastname: Yamada
authors.affiliation: Institute for material research, Tohoku University, Sendai, Miyagi, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Hanada
authors.affiliation: Institute for material research, Tohoku University, Sendai, Miyagi, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Masahashi
authors.affiliation: Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Itoi
mesh_terms: D000497:Alloys / Q000494:pharmacology*; D000818:Animals; D001031:Apatites / Q000378:metabolism*; D018786:Bone Substitutes / Q000494:pharmacology*; D055119:Elastic Modulus / Q000502:physiology*; D005269:Femur / Q000254:growth & development / Q000502:physiology; D005593:Fracture Fixation, Internal; D006801:Humans; D008297:Male; D008422:Materials Testing; D009556:Niobium / Q000737:chemistry; D010084:Oxidation-Reduction; D019736:Prostheses and Implants; D011817:Rabbits; D013499:Surface Properties; D014001:Tin / Q000737:chemistry; D014025:Titanium / Q000737:chemistry / Q000494:pharmacology; D014867:Water / Q000737:chemistry
chemical_list: D000497:Alloys; D001031:Apatites; D018786:Bone Substitutes; D009556:Niobium; D014867:Water; C031462:titanium alloy (TiAl6V4); D014001:Tin; D014025:Titanium