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.
Department of Biomaterials, College of Dental Science, University Medical Center Nijmegen, PO Box 9101, 6500 HB, Nijmegen, The Netherlands. j.wolke@dent.umcn.nl
J G C
JG
Wolke
J P C M
JP
van der Waerden
H G
HG
Schaeken
J A
JA
Jansen
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