To evaluate the effect of artificial aging on the mechanical resistance and micromechanical properties of commercially and noncommercially available zirconia dental implants. Methods: Scanning electron microscopy (SEM) and X-ray computed tomography (X-CT) were performed on implant systems including: Z-systems®, Straumann®, Zibone® and commercially and non-commercially available TAV dental® with varying grain sizes. Accelerated aging was performed at 134 °C and 2-bar pressure for 30 hours. Before and after aging, the mechanical load to failure was investigated and the bending moments were calculated. Nanoindentation responses of the representative Zibone implant before and after aging were per-formed to evaluate the effects of aging on hardness (H) and Young's modulus (E). A two-sample t-test statistical analysis was used to determine significant differences of bending moments within groups. Results: All implants presented with compact and homogenous core structures without porosities. The bending moment was significantly increased after aging for all groups (P ≤ 0.05) except for Z-systems (significant de-crease (P = 0.022)) and TAV group 3 (no significant increase (P = 0.181)). The increase in bending moment was less pronounced with increasing grain size in TAV groups (group 1: P = 0.036, group 2: P = 0.05, group 3: P = 0.18). E and H were reduced approximately 32% and 18% respectively following aging within the trans-formed, microcracked zone of the presentative Zibone implant. Conclusions: Aging led to both increase and decrease of the mechanical properties of the implant systems ana-lyzed. The apparent contrast amongst groups can be explained based on differences in grain sizes and surface features. Aging decreased micromechanical properties of one implant system which warrants further in-vestigation.

Objective Limited clinical evidence has been reported in dental literature regarding zirconia dental implants. The aim of the present retrospective consecutive case series was to evaluate the clinical outcome of zirconia dental implants with 1 to 5 years of follow‐up. Clinical considerations The clinical outcome of 24 implants in 12 consecutive patients (male 5, female 7) with a mean age of 55 years (range 27‐86) is reported. Radiographic crestal bone level was assessed by the use of “ImageJ” software program. Gingival and plaque indices were recorded at baseline and latest follow‐up. Conclusion The overall success rate of zirconia implants was 92%. Within the limitations of the present clinical evaluation, zirconia implants provided excellent clinical results and esthetic outcomes. A mean periimplant bone loss of 0.3 mm was measured in 33.3% of the implants and 66.7% were not affected by radiographic detectable periimplant bone loss. Two implants in two patients failed. Low gingival and plaque indices were predominant values for both interim and final restorations. The apparent less affinity to plaque accumulation may favor soft tissue health around zirconia dental implants and decrease the risk of inflammation or infection. Zirconia dental implant merits further investigation. Clinical significance Zirconia dental implants are emerging as an option in clinical practice of implant dentistry providing stable clinical results and esthetic outcomes.