In vivo dissolution behavior of various RF magnetron-sputtered Ca-P coatings on roughened titanium implants.
RF magnetron sputter deposition was used to produce 0.1, 1.0 and 4.0 microm thick Ca-P coatings on TiO(2)-blasted titanium discs. Half of the as-sputtered coated specimens were subjected to an additional infrared heat treatment for 30s at 425-475 degrees C. X-ray diffraction demonstrated that infrared radiation changed the amorphous 4 microm sputtered coatings into an amorphous-crystalline structure, while the amorphous 0.1 and 1 microm changed in a crystalline apatite structure with the presents of tetracalciumphosphate as a second phase. Scanning electron microscopically examination of the sputtered coatings revealed that annealing of the 4 microm thick coatings resulted in the appearance of small cracks. Subsequently, the discs were implanted subcutaneous into the back of rabbits. After 1, 4, 8 and 12 weeks of implantation, the implants were retrieved and prepared for histological and physicochemical evaluation. Histological evaluation revealed that the tissue response to all coated implants was very uniform. A very thin connective tissue capsule surrounded all implants. The capsule was usually free of inflammatory cells. At the interface, there was a close contact between the capsule and implant surface and no inflammatory cells were seen. Physicochemical evaluation showed that the 0.1 and 1 microm thick amorphous coatings had disappeared within 1 week of implantation. On the other hand, the 4 microm thick amorphous phase disappeared during the implantation periods, which was followed by the precipitation of a crystalline carbonate apatite. Further, at all implantation periods the heat-treated 1 and 4 microm thick coatings could be detected. Occasionally, a granular precipitate was deposited on the heat-treated 4 microm thick coating. Fourier transform infrared spectroscopy showed the formation of carbonate apatite (CO(3)-AP) on the 4 microm thick amorphous coating and on the heat-treated specimens. On basis of our findings, we conclude that 1 microm thick heat-treated Ca-P sputter coating on roughened titanium implants appear to be of sufficient thickness to show bioactive properties, under in vivo conditions.
Wolke
J G C
JG
Department of Biomaterials, College of Dental Science, University Medical Center Nijmegen, PO Box 9101, 6500 HB, Nijmegen, The Netherlands. j.wolke@dent.umcn.nl
van der Waerden
J P C M
JP
Schaeken
H G
HG
Jansen
J A
JA
D000818:Animals; D002130:Calcium Phosphates / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D005260:Female; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D019736:Prostheses and Implants; D011817:Rabbits; D011846:Radio Waves; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D014025:Titanium