Effect of a multiphasic anodic spark deposition coating on the improvement of implant osseointegration in the osteopenic trabecular bone of sheep

Purpose: Anodic spark deposition techniques have been effectively applied to achieve a microporous morphology on metals. To investigate the effect of a new anodic spark deposition-based treatment in the enhancement of titanium implant osseointegration in trabecular bone of aged and ovariectomized sheep, a histomorphometric and microriardness study was carried out. Materials and Methods: Ten sheep were divided into 2 groups. Five were submitted to a bilateral ovariectomy to induce an estrogen-deficiency osteopenia (Ovariectomized), and 5 were left untreated (Aged). Twenty-four months later, they underwent a bilateral implantation of commercially pure titanium screw threads in the lateral surface of femoral condyles: electrochemically treated titanium (SP) and acid-etching treated titanium (BioRough). Twelve weeks after the second operation, the animals were sacrificed and femur segments and iliac crest biopsy specimens were examined for histomorphometric and microhardness evaluations. Results: The histomorphometry of the trabecular bone of the iliac crest biopsy specimens and that around screws showed marked signs of bone rarefaction in the Ovariectomized group when compared to the Baseline and Aged groups. Significantly greater bone-implant contact was observed for SP implants in comparison with BioRough implants in both the Aged (P <.001) and Ovariectomized (P <.01) groups. No significant differences in terms of microhardness were found between SP and BioRough implants within the Aged group, while a significantly higher Bone Maturation Index was observed for SP in the Ovariectomized group (P <.05). Conclusions: The novel electrochemical treatment SP produced the most promising results and was able to introduce substantial improvements in achieving the fast and stable osseointegration of implants in osteopenic bone.