title: Osteoblast response and osseointegration of a Ti-6Al-4V alloy implant incorporating strontium.
abstract: This study investigated the surface characteristics, in vitro and in vivo biocompatibility of Ti-6Al-4V alloy implants incorporating strontium ions (Sr), produced by hydrothermal treatment using a Sr-containing solution, for future biomedical applications. The surface characteristics were evaluated by scanning electron microscopy, thin-film X-ray diffractometry, X-ray photoelectron spectroscopy, optical profilometry, contact angle and surface energy measurement and inductively coupled plasma-mass spectroscopy (ICP-MS). Human osteoblast-like cell (MG63) attachment, proliferation, alkaline phosphatase (ALP) activity, and quantitative analysis of osteoblastic gene expression on Sr-containing Ti-6Al-4V surfaces were compared with untreated Ti-6Al-4V surfaces. Fifty-six screw implants (28 control and 28 experimental) were placed in the tibiae and femoral condyles of seven New Zealand White rabbits. The osteoconductivity of Sr-containing Ti-6Al-4V implants was evaluated by removal torque testing and histomorphometric analysis after 4weeks implantation. Hydrothermal treatment produced a crystalline SrTiO(3) layer. ICP-MS analysis showed that Sr ions were released from treated surfaces into the solution. Significant increases in ALP activity (P=0.000), mRNA expressions of key osteoblast genes (osterix, bone sialoprotein, and osteocalcin), removal torque values (P<0.05) and bone-implant contact percentages (P<0.05) in both cortical and cancellous bone were observed for Sr-containing Ti-6Al-4V surfaces. The results indicate that the Sr-containing oxide layer produced by hydrothermal treatment may be effective in improving the osseointegration of Ti-6Al-4V alloy implants by enhancing differentiation of osteoblastic cells, removal torque forces and bone apposition in both cortical and cancellous bone.
authors.affiliation: Department of Periodontology, School of Dentistry, Kyungpook National University, Jung-Gu, Daegu, Republic of Korea. jinwoo@knu.ac.kr
authors.forename: Jin-Woo
authors.initials: JW
authors.lastname: Park
authors.forename: He-Kyung
authors.initials: HK
authors.lastname: Kim
authors.forename: Youn-Jeong
authors.initials: YJ
authors.lastname: Kim
authors.forename: Je-Hee
authors.initials: JH
authors.lastname: Jang
authors.forename: Hwangjun
authors.initials: H
authors.lastname: Song
authors.forename: Takao
authors.initials: T
authors.lastname: Hanawa
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000497:Alloys; D000818:Animals; D001672:Biocompatible Materials; D002448:Cell Adhesion; D002460:Cell Line; D049109:Cell Proliferation; D006801:Humans; D008855:Microscopy, Electron, Scanning; D016348:Osseointegration; D010006:Osteoblasts / Q000166:cytology* / Q000201:enzymology; D019736:Prostheses and Implants; D011817:Rabbits; D013324:Strontium; D014025:Titanium; D014961:X-Ray Diffraction
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; C031462:titanium alloy (TiAl6V4); D014025:Titanium; D000469:Alkaline Phosphatase; D013324:Strontium