Hydroxyapatite and silk combination-coated dental implants result in superior bone formation in the peri-implant area compared with hydroxyapatite and collagen combination-coated implants.

The objective of this study was to compare bone formation after installation of uncoated (UC), hydroxyapatite-coated (HA), collagen plus HA-coated (CH), and silk plus HA-coated (SH) implants. Implants in the UC group had acid-etched surfaces. Surface coating was applied using the aerosol deposition method. Cellular responses on the coated surfaces were examined with scanning electron microscopy. Cellular responses to the surfaces were studied with the corresponding coated discs and MG63 cells. Subsequently, 3-(4, 5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and alkaline phosphatase (ALP) assays were performed. Peri-implant bone formation was evaluated with the rabbit tibia model. Twenty-four implants from each group were installed. The animals were sacrificed 6 weeks after implant installation. Peri-implant bone formation and implant-to-bone contact were measured in histologic sections. Significance of differences across groups was evaluated using analysis of variance. Scanning electron microscopic images showed that the CH and SH groups exhibited cells that appeared more spread out than those in the other groups. The SH group exhibited the highest value in the MTT assay. The CH group exhibited the highest level of ALP activity. Comparisons of these modifications with the acid-etched surfaces showed that the CH and SH groups displayed significantly greater peri-implant bone formation (P < .001). The SH group displayed significantly greater new bone formation and bone-to-implant contact than did the other groups.