Fracture resistance of all ceramic crowns supported by zirconia and alumina versus titanium implant abutments

Purpose: High-strength ceramic materials can be used to fabricate esthetic and stable implant-supported single-tooth abutment. Study compared in vitro the fracture resistance of individual components of single-tooth implant-supported all-ceramic restorative systems after artificial aging and analyzing mode of failure using scanning electron microscope. Materials and methods: Forty-eight analogues represent maxillary first premolar. The implants were divided, according to the type of abutments used into three groups (of 16 specimens each): Group A: Ti titanium abutments; Group B: Al2O3 alumina abutments; Group C: ZrO2 zirconia abutments. IPS Impress crown was fabricated and cemented to abutments by resin cement (Rely X ARC) and artificially aged through dynamic loading (2400000 cycles) and thermal cycling (600 cycles). Afterwards, all specimens were tested for fracture resistance using compressive load and scanned by electron microscope. The results were statistically analyzed with one way ANOVA and t-test. Results: All test specimens survived the artificial aging process using simulated oral conditions. No screw loosening was recorded. The median fracture resistance was 844.52 ± 12.26N, 494.92 ± 8.99N and 795.56 ± 6.22N for groups Ti, Al2O3, and ZrO2, respectively. Significant differences were found for the fracture resistance comparisons of Ti and ZrO2 groups with Al2O3 one. Also significant differences were found between Ti and ZrO2 group. Conclusion: All types of implant-supported restorations tested have the potential to withstand physiologic occlusal forces applied in the premolar region (450N). Unfavorable fracture occurred in eight Al2O3 specimens indicated unfavorable behavior of this material after aging.