VARIABILITY OF HYDROXYAPATITE-COATED DENTAL IMPLANTS

Uniformity, surface roughness, and chemical phase structure are all im portant features of implant coatings. While the first two variables ar e important for implant placement, the phase structure affects implant fixation. This study examined the coating morphology and the amount, size, and distribution of crystalline regions of press-fit and screw-t ype dental implants. Implants obtained from five commercial vendors we re sectioned sagitally, mounted, and polished to reveal the coating mi crostructure. The crystalline phase content varied depending on the im plant supplier; however, general trends were observed. Amorphous regio ns were predominantly found at the metal interface and decreased towar d the outside of the coating, producing a crystallinity graded coating . The distal end of the implant, where heat build-up was more likely d uring the coating procedure, displayed a higher crystalline content an d larger crystalline regions. Similarly, the thread apex consisted of more of a crystalline phase. The results of this study of coating micr ostructure may be used to improve the quality and performance of impla nts and may help to explain different in vivo responses to the many av ailable varieties of hydroxyapatite-coated dental implants.