Histological analysis of loaded zirconia and titanium dental implants: an experimental study in the dog mandible.

Abstract

To assess whether or not peri-implant soft tissue dimensions and hard tissue integration of loaded zirconia implants are similar to those of a titanium implant. In six dogs, two one-piece zirconia implants (VC, ZD), a two-piece zirconia implant (BPI) and a control one-piece titanium implant (STM) were randomly placed. CAD/CAM crowns were cemented at 6months. Six months later, animals were killed and histomorphometric analyses were performed, including: the level of the mucosal margin, the extent of the peri-implant mucosa, the marginal bone loss and the bone-to-implant contact (BIC). Means of outcomes variables were calculated together with their corresponding 95% confidence intervals. In general, the mucosal margin was located coronally to the implant shoulder. The buccal peri-implant mucosa ranged between 2.64±0.70mm (VC) and 3.03±1.71mm (ZD) (for all median comparisons p>0.05). The relative marginal bone loss ranged between 0.65±0.61mm (BPI) and 1.73±1.68mm (ZD) (buccal side), and between 0.55±0.37mm (VC) and 1.69±1.56mm (ZD) (lingual side) (p>0.05). The mean BIC ranged between 78.6%±17.3% (ZD) and 87.9%±13.6% (STM) without statistically significant differences between the groups (p>0.05). One- and two-piece zirconia rendered similar peri-implant soft tissue dimensions and osseointegration compared to titanium implants that were placed at 6months of loading. Zirconia implants, however, exhibited a relatively high fracture rate.