Methods: Two groups of PSZ materials were provided from two manufacturers, with differing grain sizes (4 groups n=5). SEM images were used to determine grain sizes using line intercept technique. Artificial accelerated aging was accomplished using a MidMark M11 Ultraclave Automatic Sterilizer for 5 hours. A Siemens D500 XRD device with Cu-K-alpha radiation was used to measure tetragonal to monoclinic transformation (t→m). Surface roughness analysis was performed using Scantron Proscan 2000, a non-contact surface-measuring instrument. Nano-hardness and Modulus of Elasticity were measured using MTS Nano G200.
Results: Grain sizes, monoclinic transformations, surface roughness, modulus, and nano-hardness values are indicated below for each group.
Grain Size (μm) |
Aging |
Transformation(%Tm) |
Surface roughness (Ra) |
Modulus (GPa) |
Hardness (GPa) |
|
LK Group 1 |
0.224 (0.019) |
Before |
0 |
0.204(0.054) |
241.2(3.63) |
15.9(0.61) |
After |
0.39(0.46) |
0.324(0.142) |
267.7(2.82) |
16.6(0.32) |
||
LK Group 2 |
0.239 (0.015) |
Before |
0 |
0.328(0.089) |
266.7(5.37) |
16.6(0.50) |
After |
2.54(0.61) |
0.360(0.161) |
270.8(4.61) |
15.6(0.33) |
||
Lava Plus |
0.274 (0.013) |
Before |
0 |
0.156(0.051) |
299.6(5.39) |
17.0(0.32) |
After |
4.03(0.54) |
0.184(0.047) |
269.4(12.9) |
16.4(1.05) |
||
Lava |
0.368 (0.035) |
Before |
0 |
0.168(0.075) |
285.1(5.34) |
16.4(0.26) |
After |
6.64(1.01) |
0.220(0.082) |
276.3(4.81) |
16.5(0.42) |
Conclusions: Within the limits of this study, the monoclinic transformation decreases with smaller grains and the zirconia samples experienced a surface roughening upon aging. Furthermore, the modulus and hardness decreased after aging in all but one group. However, grain size did not appear to influence the amount of roughening.