Department of Prosthetic Dentistry, University Hospital, Ludwig-Maximilians-University, Goethestrasse 70, 80336, Munich, Germany.
Estetic Ceram ag, Landstrasse 109, 9495, Triesen, Liechtenstein.
J Mech Behav Biomed Mater. 2022 Jun;130:105213. doi: 10.1016/j.jmbbm.2022.105213. Epub 2022 Apr 1.
This investigation evaluated the impact of multiple firings during the veneering process of anterior all-ceramic restorations on the fracture load (FL) of zirconia crowns veneered with different ceramics (ZRT, ZRO, HFZ, STR).
All-ceramic crowns with anatomically reduced zirconia frameworks were prepared using four different veneering ceramics (N = 192/n = 48 per veneering ceramic). The crowns were fired 2 and 10 times. Half of them were thermocycled (5000 cycles, 5 °C/55 °C, 20s). FL using Voss shear test was measured. Data was analyzed using ANOVA with partial eta squared and post-hoc Scheffé-test as well as t-test and Weibull analysis.
Regarding FL, greatest differences were among the number of firings (p<0.001, η = 0.369). FL was not influenced by the interaction of both number of firings and aging level (p = 0.231) and the interaction of number of firings and veneering ceramic (p = 0.222). Differences were found comparing FL values of ZRT and STR (p<0.001) and of HFZ and STR (p<0.001). No differences occurred among the veneering ceramics after 2 (p = 0.430) and after 10 firings (p = 0.057) in respect to initial FL. For all initially tested veneering ceramics, FL showed higher values after 10 firings (p≤0.001-0.014). When aged, ZRO, HFZ, and STR also provided higher FL values after 10 firings (p≤0.001). For ZRT, FL values differed between initial and aged testing after 2 firings (p = 0.001) with aged specimens providing higher FL values. After 10 firings, none of the veneering ceramics showed differences regarding FL values between initial and aged testing. Weibull modulus was higher for ZRT specimens after 10 firings when tested initially (m = 10.1) and for aged ZRT specimens after 2 firings (m = 11.1). Failures occurred either with chipping of the veneer or total fracture.
Veneered zirconia restorations tested presented higher FL after 10 firings compared to 2 firings. Aging via thermocycling showed a positive effect on the FL.
本研究评估了在前牙全瓷修复体的贴面过程中多次烧制对涂覆不同陶瓷（ZRT、ZRO、HFZ、STR）的氧化锆冠的断裂载荷（FL）的影响。
使用四种不同的贴面陶瓷制备具有解剖学减小的氧化锆框架的全瓷冠（N=192/n=48/每种贴面陶瓷）。将牙冠烧制 2 次和 10 次。其中一半进行热循环（5000 次循环，5°C/55°C，20s）。使用 Voss 剪切试验测量 FL。使用方差分析（ANOVA）和偏 eta 平方以及事后 Scheffé 检验以及 t 检验和 Weibull 分析来分析数据。
关于 FL，烧制次数之间的差异最大（p<0.001，η=0.369）。FL 不受烧制次数和老化水平的相互作用（p=0.231）以及烧制次数和贴面陶瓷的相互作用的影响（p=0.222）。在 ZRT 和 STR（p<0.001）和 HFZ 和 STR（p<0.001）之间发现了 FL 值的差异。在经过 2 次（p=0.430）和 10 次（p=0.057）烧制后，初始 FL 方面，各贴面陶瓷之间没有差异。对于所有最初测试的贴面陶瓷，经过 10 次烧制后，FL 值更高（p≤0.001-0.014）。当老化时，ZRO、HFZ 和 STR 经过 10 次烧制后也提供了更高的 FL 值（p≤0.001）。对于 ZRT，在经过 2 次烧制后，初始和老化测试之间的 FL 值存在差异（p=0.001），老化后的标本提供了更高的 FL 值。经过 10 次烧制后，在初始和老化测试之间，没有一种贴面陶瓷的 FL 值存在差异。经过 10 次烧制后，初始测试时 ZRT 试件的 Weibull 模数更高（m=10.1），经过 2 次烧制后老化的 ZRT 试件的 Weibull 模数更高（m=11.1）。失效要么是贴面剥落，要么是完全断裂。
与 2 次烧制相比，经涂覆的氧化锆修复体经过 10 次烧制后的 FL 值更高。通过热循环进行老化对 FL 有积极影响。
