Hydroxyapatite (HAp) coatings were formed on cp titanium plates and rods by the
thermal substrate method in an aqueous solution that included 0.3 mM Ca(H2PO4)2 and 0.7 mM
CaCl2. The coating experiments were conducted at 40-140 oC and pH = 8 for 15 or 30 min. The
properties for the coated samples were studied using XRD, EDX, FT-IR, and SEM. All the specimens
were covered with HAp, which had different surface morphologies such as net-like, plate-like and
needle-like. After cleaning and sterilization, all the coated specimens were subjected to in vivo and
vitro testing. In the in vitro testing, the mouse osteoblast-like cells (MC3T3-E1) were cultured on the
coated and non-coated specimens for up to 30 days. Moreover, the specimens (φ2 x 5 mm) were
implanted in rats femoral for up to 8 weeks, the osseoinductivity on them were evaluated. In in vitro
evaluations, there were not significant differences between the different surface morphologies. In in
vivo evaluations, however, two weeks postimplantation, new bone formed on both the HAp coated
and non-coated titanium rods in the cancellous and cortical bone. The bone-implant contact ratio,
which was used for the evaluation of new bone formation, was significantly dependent on the surface
morphology of the HAp, and the results demonstrated that the needle-like coating appears to promote
rapid bone formation.
Selective inhibitors of the osteoblast proteasome stimulate bone formation in vivo and in vitro