Local tissue effects and peri-implant bone original architecture recovery induced by implants micro- and nanotopography: an in vivo study in the sheep

IC85R ePOSTER CLINICAL RESEARCH – PERI-IMPLANT BIOLOGY

Background: Surface chemical and topography modifications are currently of major interest to improve osseointegration and long-term success of dental implants. Currently, very few studies assess the performance of dental implants presenting both micro- and nanofeatures in vivo and for animal models used in the context of preclinical studies for medical device certification.

Aim/Hypothesis: This study intends to evaluate the local tissue effects and performance of a dental implant presenting both micro- and nanofeatures compared to one of identical design and material without surface treatment.

Materials and Methods: Implants surfaces are characterized in terms of topography through Scanning Electron Microscopy and surface chemical composition through Energy-Dispersive X-Ray Spectroscopy. After 4 weeks and 13 weeks of bilateral implantation in sheep femoral condyles, a total of forty explants were harvested and fixed in neutral buffered formalin. Qualitative and semi-quantitative analyses were conducted through histopathological studies to assess the local tissue effects of dental implants. Histomorphometric analyses were carried to determine bone-to-implant contact at coronal and apical regions of interest. Finally, micro-computed tomography was conducted to assess implants osseointegration at these same regions.

Results: No adverse effect was observed around implants. Histomorphometric analyses indicate that resulting bone-to-implant contact in the coronal region of the surface treated implant is significantly higher at week 4 and week 13, reaching respectively 79.3% and 86.4%, than the implant without surface treatment, reaching respectively 68.3% and 74.8%. Micro-computed tomography analyses revealed different healing patterns between the coronal and apical regions, with higher bone-to-implant contact for the coronal one at week 13. Histopathological results indicate at week 13 that bone around the surface treated implant recovered its original architecture while the implant without surface treatment still presents bone condensation and traces of the initial drill defect.

Conclusions and Clinical Implications: Such results suggest that the surface treated implant, in addition of not being deleterious for local tissues, promotes faster regeneration and remodeling of bone around the implant towards peri-implant bone original architecture recovery, allowing earlier implant load bearing and ensuring long-term implant stability.

Keywords: Osseointegration, Dental implants, Nanostructures, Surface treatment, Sheep model