Biomechanical evaluation of a microstructured zirconia implant by a removal torque comparison with a standard Ti-SLA implant

Objectives The purpose of this study was to evaluate the biomechanical bone tissue response to novel microstructured zirconia implants in comparison to sandblasted and acid-etched (SLA) titanium implants through the analysis of removal torque (RTQ) measurements. Materials and methods Ti-SLA implants with a sandblasted, large-grit and acid-etched surface were compared with zirconia implants with an acid-etched surface. All implants had the same shape, a diameter of 4.1 similar to mm and a length of 10 similar to mm. A total of 136 implants were placed in the maxillae of 17 miniature pigs. Six animals were sacrificed after both 4 and 8 similar to weeks and five animals were sacrificed after 12 similar to weeks, thus providing a total of 102 implants for RTQ testing (34 implants were reserved for future histological analysis). The RTQ analysis was successfully performed, using a mixed model regression with P-values calculated using the nonparametric Brunner-Langer method, on 100 of the 102 implants, two were excluded from the analysis. Results The adjusted mean RTQ values for Ti-SLA implants were 131 similar to Ncm (95%CI: 107155) at 4 similar to weeks, 128 similar to Ncm (108148) Ncm at 8 similar to weeks, and 180 similar to Ncm (153207 similar to Ncm) at 12 similar to weeks of healing, whereas RTQ values for the zirconia implants were 110 similar to Ncm (86134), 97 similar to Ncm (76118) and 147 similar to Ncm (121174) at the corresponding time intervals. A comparison of the implant materials resulted in P-values of P similar to=similar to 0.114 at 4 similar to weeks, P similar to=similar to 0.034 at 8 similar to weeks and P similar to=similar to 0.105 at 12 similar to weeks (significance set at P similar to<similar to 0.05). Conclusions Within the limits of the present study, it could be confirmed that the biomechanical bone-tissue response of the investigated zirconia implants is non-inferior to that of the well-documented, roughened titanium surface, at each time point, within the set tolerance. There were no statistically significant differences between the two materials after a healing period of 4 and 12 similar to weeks. The RTQ values of both implant types increased significantly from the 8-week to the 12-week time point.