Application of oxygen ion implantation to titanium surfaces: effects on surface characteristics, corrosion resistance, and bone response.
BACKGROUND
The surface oxide layer of titanium plays a decisive role in determining biocompatibility. However, there are some reports demonstrating that the natural oxide film may not be sufficiently protective in the aggressive biologic environment.


OBJECTIVE
The goal of this study was to examine the effectiveness of a thick oxide layer on corrosion resistance in vitro and the bone formation around titanium implants in vivo.


METHODS
A plasma source ion implantation (PSII) method was used to increase the thickness of the surface oxide layer. Several instruments were employed to confirm the surface properties before and after the surface modification. Potentiodynamic polarization measurements in a phosphate-buffered saline (PBS) solution were carried out to investigate corrosion resistance in vitro. Bone formation around this surface-modified specimen was examined in a rabbit model and assessed in histomorphometry.


RESULTS
Improved corrosion resistance was demonstrated by the potentiodynamic polarization measurements. Light microscopic histomorphometry showed that all implants were in contact with bone and had some proportion of bone within the threads at 4 weeks; however, there were no significant differences compared with as-machined controls.


CONCLUSIONS
The results indicate that in spite of improved corrosion resistance in vitro, a thick oxide layer fabricated with the PSII method does not influence early bone formation around titanium implants in vivo.
Sawase
T
T
Department of Biomaterials, Handicap Research Institute for Surgical Sciences, Göteborg University, Göteborg, Sweden.
Wennerberg
A
A
Baba
K
K
Tsuboi
Y
Y
Sennerby
L
L
Johansson
C B
CB
Albrektsson
T
T
D000818:Animals; D020099:Coated Materials, Biocompatible; D003343:Corrosion; D015921:Dental Implants; D004563:Electrochemistry; D004577:Electron Probe Microanalysis; D020007:Implants, Experimental; D007477:Ions; D008297:Male; D016348:Osseointegration; D011817:Rabbits; D013499:Surface Properties; D013977:Tibia; D014025:Titanium / Q000737:chemistry
D020099:Coated Materials, Biocompatible; D015921:Dental Implants; D007477:Ions; C009495:titanium dioxide; D014025:Titanium