Evaluation of nano-technology-modified zirconia oral implants: A study in rabbits

Objective: The objective of this study was to screen candidate nano-technology-modified, micro-structured zirconia implant surfaces relative to local bone formation and osseointegration. Materials and Methods: Proprietary nano-technology surface-modified (calcium phosphate: CaP) micro-structured zirconia implants (A and C), control micro-structured zirconia implants (ZiUnite™), and titanium porous oxide implants (TiUnite™) were implanted into the femoral condyle in 40 adult male New Zealand White rabbits. Each animal received one implant in each hind leg; thus, 20 animals received A and C implants and 20 animals received ZiUnite™ and TiUnite™ implants in contralateral hind legs. Ten animals/group were euthanized at weeks 3 and 6 when biopsies of the implant sites were processed for histometric analysis using digital photomicrographs produced using backscatter scanning electron microscopy. Results: The TiUnite™ surface demonstrated significantly greater bone-implant contact (BIC) (77.6±2.6%) compared with the A (64.6±3.6%) and C (62.2±3.1%) surfaces at 3 weeks (p<0.05). Numerical differences between ZiUnite™ (70.5±3.1%) and A and C surfaces did not reach statistical significance (p>0.05). Similarly, there were non-significant differences between the TiUnite™ and the ZiUnite™ surfaces (p>0.05). At 6 weeks, there were no significant differences in BIC between the TiUnite™ (67.1±4.2%), ZiUnite™ (69.7±5.7%), A (68.6±1.9%), and C (64.5±4.1%) surfaces (p>0.05). Conclusion: TiUnite™ and ZiUnite™ implant surfaces exhibit high levels of osseointegration that, in this model, confirm their advanced osteoconductive properties. Addition of CaP nano-technology to the ZiUnite™ surface does not enhance the already advanced osteoconductivity displayed by the TiUnite™ and ZiUnite™ implant surfaces.