The Effect of Implant Surfaces sputter-coated with Hydroxyapatite Target

Abstract

The aim of this study was to develop experimental titanium implants sputter-coated from a hydroxyapatite target and to evaluate peri-implant tissue responses in an animal experiment. The experimental implants were prepared from plastic rods, each of which was 1.6 mm in diameter and 7 mm in length. A thin titanium film was deposited onto the rods by DC magnetron sputtering. The surface of each rod was subsequently sputter-coated from a hydroxyapatite target by RF magnetron sputtering. The experimental implants were placed in the tibiae of 8-week-old male SD rats. Titanium-coated implants were placed as controls using the same method. Tissue samples were obtained 3, 5, 7, 10, 14, and 28 days after implant placement. Histological evaluation was performed using a light microscope, and the bone-implant contact ratios (BICs) were measured. Microstructural observations of implant-bone interfaces were made using a transmission electron microscope (TEM). Peri-implant osteoblastic activity was evaluated using samples obtained 5, 7, and 10 days after implant placement. Immunohistochemical evaluation of type I collagen, osteopontin, and osteocalcin was performed. Uniform smoothness of experimental implant surfaces was confirmed by scanning electron microscope(SEM) images. In the calcium phosphate layer, the compositional ratio of the experimental implant surface was Ca:P:O=1.0:0.79:2.8 based on the results of X-ray photoelectron spectroscopy(XPS). In the trabecular bone region, the BIC ratio was significantly higher in the experimental group than in the control group at 5, 7, 10, and 28 days after implant placement. Type I collagen, osteopontin, and osteocalcin immunostaining revealed that the experimental group tended to show positive results earlier than the control group. The results of this study suggest that surface treatment using a hydroxyapatite target and RF magnetron sputtering can enhance new bone formation during implant osseointegration.

The Effects of Implant Surface Characteristics on Surrounding Bone: A Comparative Study of Two Types of Surface Characteristics

“…Morinaga et al 16) were able to make chronological observations of mineralized tissue surrounding a similar experimental implant using micro-CT. However, the previous experimental implants had smooth surfaces 9,[16][17][18][19] , and the reaction of the peri-implant tissue is therefore expected to be different from that of the rough-surfaced implants that are currently commonplace in clinical work. The present study compared differences in periimplant tissue reactions to implants with two different types of surface characteristics.…”