Osseointegration of Titanium Implants with Different Rough Surfaces: A Histologic and Histomorphometric Study in an Adult Minipig Model

Background: Many chemical and physical modifications of titanium surfaces were introduced, aiming at improving surface bioactivity, but few comparative evidence exists. Objective: To evaluate histologically in minipigs the osseointegration of implants made of commercially pure (CP) titanium or titanium alloy, treated by different roughening procedures. Material and Methods: Three sandblasted acid-etched (SA) surfaces, 2 anodized (AN), and 1 double acid-etched (DAE) were compared. Surface microtopography was characterized with scanning electron microscope; surface element composition was also assessed. One implant per group was inserted in each proximal tibia of 2 minipigs. Three months after healing, block biopsies were taken for histomorphometric analysis. Implant stability quotient (ISQ) was measured at insertion and before harvesting. Results: The highest amount of cortical bone-implant contact was observed around SA implants and showed positive correlation with surface roughness. The greatest increase in ISQ was observed in CP-AN implants. In the medullary region, SA implants showed the best osteogenic response, whereas inflammatory cells were found around DAE and alloy-AN implants. Conclusions: SA surfaces were more osteogenic than anodized or dual acid-etched ones, although not significantly. Surface roughness affected osseointegration.