Comparative analysis of osseointegration of titanium implants with acid-etched surfaces and different biomolecular coatings.

Objectives: An increasing trend toward implantation in complex cases, as well as early loading, is beginning to emerge in dental implantology. Long-term stability of the inserted implants greatly depends on the osseointegration process. Although there are numerous current research efforts aimed at functionalizing implant surfaces, no single factor has proved to be beneficial for osseointegration. The aim of the present study was to investigate whether a combination coating of collagen I and different cytokines enhances osseointegration.

Study Design: Commercially available titanium implants (Semados S; Bego Implant Systems, Bremen, Germany) were coated with collagen I and either 1 μg or 10 μg of bone morphogenic protein 2, vascular endothelial growth factor 165, basic fibroblast growth factor 2, or a combination of all 3 factors by using the biodot method. Experimental implants (1 pure titanium, 1 collagen I coated and 8 different cytokine coatings) were inserted in the frontal skulls of 9 domestic pigs (10 implants in each animal). Implants were retrieved 2, 4, and 8 weeks after surgery. Samples were subjected to microradiography and immunohistochemistry for collagen I and osteocalcin.

Results: Implant coating with collagen I significantly increased collagen I (P = .028) and osteocalcin (P = .037) expression at the 2-week follow-up and osteocalcin expression (P = .042) as well as the bone implant contact (P = .049) at the 4-week follow-up compared with pure titanium. Additional cytokine coating had no significant effect compared with the collagen I coating.

Conclusions: It can be concluded that collagen I coating enhances osseointegration. However, additional growth factor application has no further beneficial effects.