Osseointegration of Zirconia (Y-TZP) Dental Implants: A Histologic, Histomorphometric and Removal Torque Study in the Hip of Sheep

Objectives: The purpose of the present study was to demonstrate the biocompatibility and rigid osseointegration of a zirconia (Y-TZP) dental implant with acid-etched surface. Materials and methods: Eight zirconia (Y-TZP) implants (CeraRoot, Barcelona) were inserted in the hip of an adult sheep. The animal was sacrificed after 2 months. Four implants were used for histology and histomorphometric analysis, and the other four implants were used for removal torque test (RTQ). Results: The histological evaluation showed a direct bone to implant contact (BIC) with no signs of inflammatory or foreign body reaction. The histomorphometric analysis values ranged from 79.5 to 79.9% of BIC. The RTQ showed values ranging from 75 to 83 Ncm. Discussion: In this animal study, the biocompatibility of CeraRoot zirconia (Y-TZP) implants was demonstrated with the histologic observations of healthy bone tissue in direct contact with the zirconia (Y-TZP) implant surface. Moreover, the histomorphometric analysis and the RTQ confirmed a rigid fixation of the implant within the bone. Comparative studies with acid-etched titanium implants are needed to further evaluate the characteristics of CeraRoot zirconia dental implants.