title: Spark anodization of titanium-zirconium alloy: surface characterization and bioactivity assessment.
abstract: Titanium (Ti) and its alloys have been popularly used as implant biomaterial for decades. Recently, titanium-zirconium (TiZr) alloy has been developed as an alternative implant material with improved strength in load bearing areas. Surface modification is one of the key factors to alter the surface properties to hasten osseointegration. Spark anodic oxidation (anodization) is one such method that is reported to enhance the bone formation around implants. This study aims to anodize TiZr and study its surface characteristics and cytocompatibility by cell culture experiments using osteoblast-like cells. Titanium (Ti) and TiZr discs were anodized in an electrolyte containing DL-α-glycerophosphate and calcium acetate (CA) at 300 V. The surface characteristics were analyzed by scanning electron microscopy, electron dispersive spectroscopy, X-ray diffraction (XRD), atomic force microscopy and goniometry. Using osteoblast-like cells viability, proliferation, differentiation and mineralization was assessed. The anodized surfaces demonstrated increased oxygen, entrapped calcium and phosphorous from the electrolyte used. XRD analysis confirmed the presence of anatase in the oxide layer. Average roughness increased and there was a significant decrease in contact angle (P < 0.01) following anodization. The anodized TiZr (aTiZr) surfaces were more nano-porous compared to anodized Ti (aTi). No significant difference was found in the viability of cells, but after 24 h the total number of cells was significantly higher (P < 0.01). Proliferation, alkaline phosphatase activity and calcium deposits were significantly higher on anodized surfaces compared to machined surfaces (P < 0.05, ANOVA). Anodization of TiZr resulted in a more nanoporous and hydrophilic surface than aTi, and osteoblast biocompatibility appeared comparable to aTi.
authors.affiliation: Department of Oral Sciences, Faculty of Dentistry, Sir John Walsh Research Institute, University of Otago, Walsh Building, 310 Great King Street, Dunedin, 9016, New Zealand, ajsharma.perio@gmail.com.
authors.forename: Ajay
authors.initials: A
authors.lastname: Sharma
authors.forename: A James
authors.initials: AJ
authors.lastname: McQuillan
authors.forename: Lavanya A
authors.initials: LA
authors.lastname: Sharma
authors.forename: John Neil
authors.initials: JN
authors.lastname: Waddell
authors.forename: Yo
authors.initials: Y
authors.lastname: Shibata
authors.forename: Warwick John
authors.initials: WJ
authors.lastname: Duncan
mesh_terms: D000497:Alloys / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D002470:Cell Survival; D006801:Humans; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D016348:Osseointegration; D010006:Osteoblasts / Q000166:cytology; D019736:Prostheses and Implants; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; C000599177:Ti-Zr alloy; D015040:Zirconium; D014025:Titanium