Osteoblast and bone tissue response to surface modified zirconia and titanium implant materials.

Objective: This study examined the in vitro and in vivo response of osteoblasts to a novel, acid-etched and sandblasted zirconia surface.

Methods: Osteoblastic hFOB 1.19 cells were cultured either on electrochemically anodized titanium (TiUnite(®)), machined titanium (Ti-m), sandblasted and acid-etched zirconia (TZP-proc), and machined zirconia (TZP-A-m). The surface topography of the various substrates was analyzed by 3D laserscan measurements and scanning electron microscopy. At culture days 1, 3, 7, 14, 21, and 28, cell proliferation was determined. Gene expression was analyzed using RT-PCR. Histologic analysis and biomechanical testing was performed on miniature implants placed in the rat femur.

Results: During the first 7 days, a retarded cell proliferation was observed on the TiUnite(®) surface. After 28 days of cultivation, cell proliferation reached similar levels on all surfaces. An up-regulation of bone and extracellular matrix specific genes could be seen for TZP-proc at day 21. The mean bone-implant contact rate after a healing period of 14 and 28 days, respectively, was higher for TiUnite(®) than for TZP-proc. At 28 day, the biomechanical test showed significantly higher values for TiUnite(®) than for all other surfaces.

Significance: The novel, rough zirconia surface was accepted by hFOB 1.19 cells and integrates into rat bone tissue. However, osseointegration seemed to proceed more slowly and to a lesser extent compared to a moderately roughened titanium surface.