Enhanced osteoblast response to hydrophilic strontium and/or phosphate ions-incorporated titanium oxide surfaces.
OBJECTIVE
This study investigated the surface characteristics and in vitro biocompatibility of titanium (Ti) surfaces incorporated with strontium ions (Sr) and/or phosphate ions (P) produced by hydrothermal treatment for future applications as endosseous implant surfaces.


METHODS
Sr and/or P-incorporated Ti oxide surfaces were produced by hydrothermal treatment. The surface characteristics were evaluated by scanning electron microscopy, thin-film X-ray diffractometry, X-ray photoelectron spectroscopy, contact angle and surface energy measurements, inductively coupled plasma atomic emission spectroscopy, and profilometry. MC3T3-E1 pre-osteoblast cell attachment, morphology of spread cells, viability, and quantitative analysis of osteoblastic gene expression on grit-blasted microrough (RBM), P-incorporated (P), and P- and Sr-incorporated (SrP) Ti surfaces were evaluated.


RESULTS
Microstructured P and SrP surfaces showed significantly higher wettability and surface energy compared with RBM surfaces (P<0.01). After immersion in Hank's balanced salt solution, considerable apatite deposition was observed on the P and SrP surfaces. Sr incorporation significantly increased cellular attachment and viability compared with other surfaces (P<0.05). Real-time polymerase chain reaction analysis showed markedly higher mRNA expressions of the osteoblast transcription factor gene (Runx2) and the osteoblast phenotype genes (alkaline phosphatase, osteopontin, bone sialoprotein, and osteocalcin) in cells grown on the P and SrP surfaces compared with those on the RBM surface.


CONCLUSIONS
These results demonstrate that Sr- and P-incorporated Ti oxide surfaces may improve implant bone healing by enhancing attachment, viability, and differentiation of osteoblastic cells.
Department of Periodontology, School of Dentistry, Kyungpook National University, 188-1, Samduk 2Ga, Jung-Gu, Daegu 700-412, Republic of Korea. jinwoo@knu.ac.kr
Jin-Woo
JW
Park
Youn-Jeong
YJ
Kim
Je-Hee
JH
Jang
D016475:3T3 Cells; D000469:Alkaline Phosphatase / Q000096:biosynthesis / Q000235:genetics; D000818:Animals; D001031:Apatites / Q000138:chemical synthesis; D002448:Cell Adhesion; D049109:Cell Proliferation; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D050659:Core Binding Factor Alpha 1 Subunit / Q000096:biosynthesis / Q000235:genetics; D015870:Gene Expression; D006358:Hot Temperature; D007477:Ions; D051379:Mice; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism*; D015675:Osteocalcin / Q000096:biosynthesis / Q000235:genetics; D053495:Osteopontin / Q000096:biosynthesis / Q000235:genetics; D010710:Phosphates; D056951:Photoelectron Spectroscopy; D013324:Strontium; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D017155:Wettability; D014961:X-Ray Diffraction
D001031:Apatites; D020099:Coated Materials, Biocompatible; D050659:Core Binding Factor Alpha 1 Subunit; D007477:Ions; D010710:Phosphates; C493716:Runx2 protein, mouse; D015675:Osteocalcin; D053495:Osteopontin; C009495:titanium dioxide; C052774:strontium phosphate; D014025:Titanium; D000469:Alkaline Phosphatase; D013324:Strontium