Nano‐Structuring of Zirconia Implant Surfaces as an Approach to Improve Clinical Performance and Economic Efficiency—A Preclinical Study on Osseointegration

Nano-structuring of zirconia dental implants would simplify the production process compared to the currently applied sandblasting and etching. Prior in vitro studies even revealed faster cell spreading and increased viability of osteoblasts on nano-structured zirconia surfaces. The objective was to evaluate the osseointegration potential of nano-structured zirconia implants in a sheep model. Three different nano-structured surfaces were compared to a commercially available control (ZLA) by measuring the mean bone change (MBC) in radiographs and by histomorphometric analysis after 4 and 8 weeks in sheep. Radiographic and histomorphometric measurements were subjected to Kruskal-Wallis ANOVAs to test the effects of surface and time point (α = 0.05). The overall MBC increased from implant placement to 4 (0.9 mm ± 0.8 mm) to 8 weeks (1.3 mm ± 0.7 mm) (p = 0.009) with no significant differences between the groups. Histological assessment revealed that bone-to-implant contact (BIC) was increased for the micro-structured control surface compared with the nano-structured surfaces at both time points. Bone remodeling was similar for all surfaces and increased from 4 to 8 weeks. BIC in the sheep model is more dependent on surface roughness on a micro- than nano-structured level, while bone remodeling in the present setup was not influenced by surface topography. Nano-structured zirconia surfaces may be an option for clinical application; however, further research using loaded implants is needed to clarify whether BIC is sufficient to achieve long-term stability.