A Comparison of Fabrication Precision and Mechanical Reliability of 2 Zirconia Implant Abutments

Purpose: Studies have described the reliability of zirconia as an implant abutment material. The purpose of this in vitro study was to compare the precision and fracture strength of 2 different zirconia abutments angled at 30 degrees and loaded to failure in a standardized testing device. Materials and Methods: Twenty-nine Atlantis abutments in zirconia (AAZ) and 29 Nobel Biocare Procera AllZirkon abutments of comparable interface were measured for key interface feature statistical differences (analysis of variance; a = 95%). Each specimen was fixed to a regular-platform Brånemark System implant and mounted in an Instron machine. Increasing incremental loads were applied until failure. A 2-tailed t test for independent specimens and unequal variances was employed (a = 95%). The Weibull method determined the probability of failure of each abutment sample (a = 95%). Fractography by scanning electron microscopy determined the flaws at the fracture origins. Results: Metrology inspection indicated that the AAZ showed no measurable dimensional differences of 4 key interface features. The mean failure load of the AAZ (831 N) was greater than the AllZirkon (740 N; P .00006). The Weibull distribution showed that the AAZ would be more likely to survive intraoral occlusal loads (P .0005). Conclusions: Both types of zirconia abutments demonstrated failure loads that exceed maximum human bite force. In vitro, the AAZ outperformed the AllZirkon in survivability. The clinical use of zirconia abutments is indicated when esthetics may be of concern. Keywords: fractography, fracture strength, key interface features, metrology inspection, Weibull modulus