Morphological Assessment of Osseointegration of Titanium Implants with Ag- and Zn-Containing Calcium Phosphate Coatings

Background. The condition of the implant surface plays an important role in extending the service life of implants and metal structures in the human body. The aim of the study — to assess the effect of titanium implants with Ag- or Zn-containing calcium phosphate coatings on the surrounding bone tissue in experimental study. Methods. Using light microscopy, we studied the condition of bone tissue in the proximal tibia (PT) of rabbits 4 weeks after the implantation of 3D-printed titanium cone-shaped implants with Ag- or Zn-containing calcium phosphate coating. Results. In all cases, 3D-printed titanium implants with a rough surface integrated in the PT adhered very tightly to the bone tissue, the edges of which had minor cicatricial changes. Removal of the implants was difficult, and many tissue fragments remained on their surface. Small foreign fragments were present in the bone tissue samples examined. The sizes of foreign fragments were smaller after the use of silver ions, compared to the use of zinc ions, in both compact and cancellous bone by 84.4% (9.50±4.17 vs 17.78±7.95 μm) and 87.2% (11.21±10.68 vs 20.67±8.08 μm), respectively. In cancellous bone, the average diameter of the fragment groups and the average distance between the coating fragments or their groups were not statistically significantly different. In compact bone, they were 59.1% (155±35.98 vs 246.67±39.62 μm) and 21.2% (253.04±44.87 vs 308±50.85 μm) larger, respectively, after application of the Zn-containing coating. Conclusions. Surface-modified titanium implants have demonstrated a tendency to osseointegration, even when the coating is damaged with the formation of foreign fragments migrating into the surrounding tissues. It is possible that modifying the technique and modes of coating application, as well as varying their thickness, will enable the full realization of the positive properties of the modified surface, including the beneficial antimicrobial characteristics of silver and zinc.