In vitro and in vivo studies of ultrafine-grain Ti as dental implant material processed by ECAP

• Published in: Materials Science & Engineering C 2016-10, Vol.67, p.34-41
• Main Authors: An, Baili, Li, Zhirui, Diao, Xiaoou, Xin, Haitao, Zhang, Qiang, Jia, Xiaorui, Wu, Yulu, Li, Kai, Guo, Yazhou
• Format: Article
• Language: English
• Subjects: Animals; Biocompatibility; Cell Adhesion; Cell Proliferation; Commercially pure titanium (CP-Ti); Dental implant; Dental Implants; Dental materials; Equal channel angular pressing; Equal channel angular pressing (ECAP); In vitro testing; In vivo methods and tests; Materials Testing - methods; Rabbits; Sandblasting and acid-etching (SLA); Surface Properties; Surgical implants; Titanium; Titanium base alloys; Ultrafine-grain titanium (UFG-Ti)
• ISSN: 0928-4931; 1873-0191
• DOI: 10.1016/j.msec.2016.04.105

The aim of this study was to investigate the surface characterization of ultrafine-grain pure titanium (UFG-Ti) after sandblasting and acid-etching (SLA) and to evaluate its biocompatibility as dental implant material in vitro and in vivo. UFG-Ti was produced by equal channel angular pressing (ECAP) using commercially pure titanium (CP-Ti). Microstructure and yield strength were investigated. The morphology, wettability and roughness of the specimens were analyzed after they were modified by SLA. MC3T3-E1 osteoblasts were seeded onto the specimens to evaluate its biocompatibility in vitro. For the in vivo study, UFG-Ti implants after SLA were embedded into the femurs of New Zealand rabbits. Osseointegration was investigated though micro-CT analysis, histological assessment and pull-out test. The control group was CP-Ti. UFG-Ti with enhanced mechanical properties was produced by four passes of ECAP in BC route at room temperature. After SLA modification, the hierarchical porous structure on its surface exhibited excellent wettability. The adhesion, proliferation and viability of cells cultured on the UFG-Ti were superior to that of CP-Ti. In the in vivo study, favorable osseointegration occurred between the implant and bone in CP and UFG-Ti groups. The combination intensity of UF- Ti with bone was higher according to the pull-out test. This study supports the claim that UFG-Ti has grain refinement with outstanding mechanical properties and, with its excellent biocompatibility, has potential for use as dental implant material. [Display omitted] •Yield strength and Vickers hardness of Ti are improved significantly after it is grain-refined by ECAP process.•The hierarchical micro-porous structure with superior wettability could be formed on the surface of ECAP Ti after SLA.•The results in vitro exhibited excellent cell biocompatibility of UFG-Ti after sandblasting and acid-etching.•The osseointegration between UFG-Ti implant and surrounding bone could be enhanced in vivo study.