Effect of framework design on crown failure
Effect of framework design on crown failure
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DOI：
10.1111/j.1600-0722.2008.00608.x
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发表时间：
2009-04-01
影响因子：
1.9
通讯作者：
Bonfante, Gerson
中科院分区：
文献类型：
--
作者：
Bonfante, Estevam A.;da Silva, Nelson R. F. A.;Bonfante, Gerson
本研究评价了玻璃渗透氧化铝（In-Ceram）（伊卡）与金属烤瓷（PFM）相比，核设计修改对特征强度和失效模式的影响。制作标准设计（PFMs和ICA）或改良框架设计（PFMm和ICAm）的前磨牙牙冠，将其粘固在模具上，并加载直至失效。在中央窝处使用6.25 mm碳化钨球以0.5 mm min（-1）加载牙冠。记录断裂载荷值，并使用扫描电子显微镜评估代表性样本的断裂分析。计算每组的概率Weibull曲线和双侧90%置信限，并获得特征强度的等高线图。设计修改显示PFMm和ICAm组的特征强度增加，PFM组显示出比伊卡组更高的特征强度。PFMm组在所有组中表现出最高的特征强度。PFMs和PFMm的断裂模式经常在舌尖处到达核心界面，而伊卡表现出通过氧化铝核心的大块断裂。核设计修改显着提高了PFM和伊卡的特征强度。PFM组的特征强度高于伊卡组。
This study evaluated the effect of core-design modification on the characteristic strength and failure modes of glass-infiltrated alumina (In-Ceram) (ICA) compared with porcelain fused to metal (PFM). Premolar crowns of a standard design (PFMs and ICAs) or with a modified framework design (PFMm and ICAm) were fabricated, cemented on dies, and loaded until failure. The crowns were loaded at 0.5 mm min(-1) using a 6.25 mm tungsten-carbide ball at the central fossa. Fracture load values were recorded and fracture analysis of representative samples were evaluated using scanning electron microscopy. Probability Weibull curves with two-sided 90% confidence limits were calculated for each group and a contour plot of the characteristic strength was obtained. Design modification showed an increase in the characteristic strength of the PFMm and ICAm groups, with PFM groups showing higher characteristic strength than ICA groups. The PFMm group showed the highest characteristic strength among all groups. Fracture modes of PFMs and of PFMm frequently reached the core interface at the lingual cusp, whereas ICA exhibited bulk fracture through the alumina core. Core-design modification significantly improved the characteristic strength for PFM and for ICA. The PFM groups demonstrated higher characteristic strength than both ICA groups combined.