Comparative Analysis of Osseointegration Using Titanium Implants Coated with Graphene and Niobium: An Animal Model Study

Background: Surface modification may influence tissue–implant interactions. This exploratory study compared the biomechanical, coating-integrity, and histological responses associated with uncoated titanium and carbon- or niobium-containing surface-processing conditions in a rabbit model. Methods: Twelve adult male New Zealand White rabbits were initially enrolled and allocated to 30- and 60-day healing periods. Two animals were lost before endpoint and were not replaced; ten rabbits completed the study and were analyzed, with five animals at each period. Each rabbit received four implant-site conditions: uncoated titanium, carbon-based diamond-like carbon (Graphene-DLC), niobium deposited by chemical vapor deposition (Nb-CVD), and niobium deposited by sol–gel processing (Nb-Gel). Implant stability was assessed using reverse-torque testing after formalin fixation. Histological evaluation included hematoxylin and eosin and Picrosirius Red staining. Results: At 60 days, the uncoated titanium and Graphene-DLC conditions showed the highest reported mean reverse-torque values, whereas some niobium-containing conditions showed lower reported coating-integrity scores. Ordinal histological outcomes were interpreted descriptively because the sample was small, implant sites were clustered within rabbits, and implant condition was fixed to anatomical site. Conclusions: Under this protocol, the observed differences describe combined implant-site conditions and do not provide unbiased causal evidence of coating-specific effects. The findings are exploratory and support further studies using randomized or counterbalanced allocation, clustered analysis, and independent biomechanical and histological specimens.