ABSTRACT
In this study, we evaluated early bone responses to a vitronectin-derived, minimal core bioactive peptide, RVYFFKGKQYWE motif (VnP-16), both in vitro and in vivo, when the peptide was treated on sandblasted, large-grit, acid-etched (SLA) titanium surfaces. Four surface types of titanium discs and of titanium screw-shaped implants were prepared: control, SLA, scrambled peptide-treated, and VnP-16-treated surfaces. Cellular responses, such as attachment, spreading, migration, and viability of human osteoblast-like HOS and MG63 cells were evaluated in vitro on the titanium discs. Using the rabbit tibia model with the split plot design, the implants were inserted into the tibiae of four New Zealand white rabbits. After two weeks of implant insertion, the rabbits were sacrificed, the undecalcified specimens were prepared for light microscopy, and the histomorphometric data were measured. Analysis of variance tests were used for the quantitative evaluations in this study. VnP-16 was non-cytotoxic and promoted attachment and spreading of the human osteoblast-like cells. The VnP-16-treated SLA implants showed no antigenic activities at the interfaces between the bones and the implants and indicated excellent bone-to-implant contact ratios, the means of which were significantly higher than those in the SP-treated implants. VnP-16 reinforces the osteogenic potential of the SLA titanium dental implant.
ABSTRACT
This study evaluated how zirconia thickness affects shear bond strength (SBS) between zirconia and dual-cure resin cement. Eighty specimens (40 blocks of 1 mm thickness zirconia and 20 of each 1.5 and 2 mm) were divided into 8 groups according to zirconia thickness and light-curing time. Group A, B, C, and D were light-polymerized during 20 s and group E, F, G, and H were light-cured during 40 s. Self-adhesive dual-cure resin cement was placed onto the zirconia surfaces and then light-polymerized. The mean SBS of the 40 s curing time group was statistically higher than that of the 20 s curing time group. However, curing time did not affect the SBS significantly in the 2 mm thickness groups. The mean SBS of the 1.5 and 2 mm groups were statistically lower than those 1 mm groups. Therefore, zirconia thickness significantly affected the SBS of self-adhesive dual-cure resin cement.