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Effect Of Speed Sintering And Aging On Translucency Of High-Translucent Zirconia

Posted on:2024-06-21Degree:MasterType:Thesis
Country:ChinaCandidate:Y LiFull Text:PDF
GTID:2544307064962849Subject:Stomatology
Abstract/Summary:PDF Full Text Request
Purpose:The purpose of this in vitro study was to evaluate the effect of speed sintering and low-temperature degradation on the translucency of high-translucent zirconia,and compared with high-strong zirconia.Material and method:Total of 120 square-shaped specimens with length of 10 mm and thickness of 1.5mm were prepared from CAD\CAM A2 color ST-ML and TT-ML zirconia blocks from Upera according to 22% sintering ratio,with 60 pieces each.The ST-ML and TT-ML specimens were randomly divided into two groups according to the sintering process.The conventional sintering of ST-ML was heated to a final temperature of 1530℃ held for 2 hours,while the speed sintering was heated to 1550℃ and held for 10 minutes.The conventional sintering of TT-ML was heated to a final temperature of 1480℃ and held for 2 hours,while the speed sintering was heated to 1500℃ and held for 10 minutes.The sintered specimens were divided into 3 subgroups according to the aging time,which were respectively aged for 0 hours,5 hours and 20 hours.The aging procedures were performed at 134℃ and at 0.2MPa.Chromatics characteristic parameters(L*,a*,b* values)were respectively measured by Shade Eye NCC computer colorimeter(SHOFU,Japan)in a dark environment under black and white background,and using translucency parameter(TP)to evaluate the translucency of zirconia.The surface morphology was observed by field emission scanning electron microscopy(SEM).SPSS 25.0 was used for statistical analysis,two-factor analysis of variance and Bonferroni were used for comparative analysis,and the test level α=0.05.Result:1.As for the effect of speed sintering on the translucency of zirconia,for ST-ML,the TP value of speed sintering was significantly lower than that of conventional sintering(P < 0.05),while for TT-ML,the TP value of speed sintering was significantly higher than that of conventional sintering(P < 0.05).2.As for the effect of low-temperature degradation on the translucency of zirconia,TP value of ST-ML decreased with the extension of aging time(P < 0.05),and no significant difference was found in rapid sintering ST-ML(P>0.05).Although the TP value of TT-ML was decreased,there was no statistical difference(P > 0.05).3.The interaction between speed sintering and low-temperature degradation has a significant effect on the translucency of high-strong zirconia ST-ML and hightranslucent zirconia TT-ML(P < 0.05).4.Scanning electron microscopy(SEM)showed that the grain size decreased significantly after speed sintering of ST-ML,and no significant difference was observed in TT-ML.After low-temperature degradation,the two kinds of zirconia surface can be intergranular ejection and microcracks.Conclusion:1.Speed sintering may decrease the translucency of high-strong zirconia and increase the translucency of high-translucent zirconia.2.Low-temperature degradation may decrease the translucency of high-strong zirconia and there is no effect of low-temperature degradation on the translucency of high-translucent zirconia.3.Speed sintering can be recommended for high-translucent zirconia in terms of translucency.
Keywords/Search Tags:speed sintering, low-temperature degradation, high-translucent zirconia, translucency
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