Effects of microrough and hierarchical hybrid micro/nanorough surface implants on osseointegration in ovariectomized rats: A longitudinal in vivo microcomputed tomography evaluation.

This study aimed to evaluate the effects of microrough and hierarchical hybrid micro/nanorough surface implants on osseointegration in ovariectomized rats at different time points. Implants with machined, microrough and hierarchical hybrid micro/nanorough surfaces were inserted into the distal femurs of ovariectomized Sprague-Dawley female rats. At weeks 0, 4, and 12 following implantation, in vivo microcomputed tomography (micro-CT) scanning was used to assess bone microarchitectural changes. After 12 weeks, all the rats were sacrificed, and the femurs with implants were harvested for histological analysis and pull-out test. For the Micro-CT analysis, the trabecular number and the bone volume ratio increased significantly in the microrough group (p < 0.01) and micro/nanorough group (p < 0.01) compared with the machined group. The trabecular separation decreased significantly in the micro/nanorough group (p < 0.01) compared with the other two groups. For the maximum pull-out forces and the bone-implant-contact analyses, significant statistical differences were found among the three groups, with the following sequence: micro/nanorough group > microrough group > machined group. The results indicate that the microrough and the hierarchical hybrid micro/nanorough surfaces of the implant can be beneficial to osseointegration under osteoporotic conditions, and the hierarchical hybrid micro/nanorough surface is more efficient.