Surface Modification Enhances Osteoblast Behavior and Bone Formation on Thin Hydroxyapatite Layers Deposited Using a Novel Anodization-Hydrothermal Treatment on Commercially Pure Titanium Endosseous Implants

In the present study, we assessed the effects of commercially pure titanium (cpTi) by anodic oxidation and hydrothermal treatment (SA-treated cpTi) on osteoblastic differentiation and interfacial bone formation through parallel in vitro and in vivo investigations. Osteoblast cells were cultured on SA-treated cpTi disks for 5, 7, 10, and 14 days. Bone matrix mineralization was assessed by EPMA. The levels of collagen I, alkaline phosphatase, osteocalcin, osteopontin, bone sialoprotein, and β-actin mRNA were analyzed using RT-PCR. In addition, SA-treated cpTi implants were placed in the mandibles of beagles for 14 days, and then examined histologically by light microscopy. Widespread Ca and P signals were observed early in the in vitro culturing period, and mRNA expression was up-regulated in cells that were in contact with the SA-treated cpTi. The bone-to-implant contact formed at the mandible SA-treated cpTi implant sites involved direct contact of the implant with the surrounding bone tissue. These results demonstrate the potential of SA-treated cpTi surfaces for enhancing surface-specific expression of osteoblastic phenotypes and for inducing changes in bone matrix gene expression.