In vivo dissolution behavior of various RF magnetron sputtered Ca-P coatings.
Radiofrequency magnetron sputter deposition was used to deposit Ca-P sputter coatings on titanium discs, and these coatings were implanted subcutaneously into the backs of rabbits. Half of the as-sputtered coatings were subjected to additional heat treatment for 2 h at 500 degrees C. X-ray diffraction (XRD) demonstrated that annealing at 500 degrees C changed the amorphous sputtered coating into an amorphous-crystalline apatite structure. Scanning electron microscopic (SEM) examination of the sputtered coatings showed excellent coverage of the substrate surface. Annealing of the 4-microm-thick coatings resulted in the appearance of small cracks. SEM demonstrated that until 4 weeks of implantation, all heat-treated coatings were present and all amorphous coatings were completely or mostly dissolved. Fourier transform infrared spectroscopy showed the formation of carbonate apatite (CO3-AP) on these specimens. Furthermore, XRD analysis showed that these CO3-AP precipitated coatings disappeared after 8 weeks of implantation. On the other hand, SEM inspection of these specimens revealed that the 4-microm heat-treated coating was still partially maintained and that small Ca-P crystals were present on the titanium substrate. On the basis of these results, we conclude that apparently 0.1 microm heat-treated Ca-P sputter coating is of sufficient thicknesses to stimulate carbonate apatite deposition under in vivo conditions.
Wolke
J G
JG
Department of Oral Function, Dental School, University of Nijmegen, The Netherlands.
de Groot
K
K
Jansen
J A
JA
D000818:Animals; D001672:Biocompatible Materials; D002118:Calcium; D008280:Magnetics; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010758:Phosphorus; D011817:Rabbits; D011846:Radio Waves; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
D001672:Biocompatible Materials; D010758:Phosphorus; D002118:Calcium