| Zirconia ceramic has excellent biocompatibility, aesthetic and mechanical properties,has been widely used in the field of prosthodontics. But the inherent brittleness of theceramic, zirconia ceramic in the the oral environment, may occur failure fault, this case isconsidered to be the fatigue behavior of the material. Scholars have done a lot of researchin zirconia ceramic materials, mostly focused on the development and new coatingtechnology of the materials,made the performance of the material and processingtechnology greatly improved in recent years, but the research on the zirconia ceramicfatigue behavior is still in the infancy stage,and the research has not yet reached aconclusion for the mechanism of fatigue. For the fatigue test, the results vary widely.Objective: Two dental zirconia ceramic(Wieland and Aidite) was choosen for fatiguetest, combination experimental and theoretical analysis method, the fatigue life of thezirconia ceramic has being analysis and forecasting, Methods:1) zirconia ceramic were under different loading rates for three-point bending test andthe stress corrosion index n and the value of the constant B were calculate.2) through the crack propagation theory, the use of the obtained stress corrosionindex n and the value of the constant B, to predict the static fatigue life and the cyclefatigue life of two zirconia ceramics, drawing the stress-life figure.3) By the use of the Hertz contact method,different cyclic frequency were test on thezirconia ceramic, and flexural strength test after loading, compare the test results and datawas examined using Weibull analysis.4) Using the residual strength theory, analysis the strength decreased of the zirconiaceramic after cycling test, to correct the theoretical analysis with previously theoreticallife.Results:1) At three loading speed,WL’s bending strength were（861.50±76.50）MPa、（889.38±121.22）MPa、（915.33±97.83）MPa and the AT’s bending strength were（590.63±121.75）MPa、（610.50±210.14）MPa、（622.76±82.66）MPa, WL has a strengthhigher than that of AT (P <0.05). With the loading rate decrease, WL and AT showing thecharacteristics of resistance to dynamic fatigue,the strength show no significant change(P>0.05), only slight decrease in the average intensity. WL’s stress corrosion index n=76.58, AT’s stress corrosion index n=52.76.2) life prediction showed a monotonically decreasing trend with the stress increase.3) Cyclic loading experiments show that the the WL and AT’s residual strength willdecrease with the number of cycles increase.In WL ceramics exhibit a better resistance tocyclic fatigue characteristics than AT. Weibull modul found descending follow itsascending And the trend characteristic strength shown an overall downward trend.4) the WL and AT residual strength and number of cycles was fllow the law ofdecline exponent. According to the results of revisions to the predictions of the WL andAT zirconia ceramic life time, the two ceramic showed more than two decades life time. Conclusion: The WL and AT ceramic intensity can meet the needs of clinicalapplication, the useful life of more than two decades, and have shown a certain amount ofresistance to dynamic fatigue. Compared WL performance than the AT Ceramic,WLshowed higher strength and better resistance to cyclic fatigue. |
PDF Full Text Request