Objective

Porcelain fused to zirconia (PFZ) restorations are widely used in prosthetic dentistry. However, their tendency to delaminate along the P/Z interface remains a practical problem so that assessing and improving the interfacial strength are important design aspects. This work examines the effect of modifying the zirconia veneering surface with an in-house felspathic glass on the interfacial fracture resistance of fused P/Z.

Methods

Three material systems are studied: porcelain fused to zirconia (control) and porcelain fused to glass-graded zirconia with and without the presence of a glass interlayer. The specimens were loaded in a four-point-bend fixture with the porcelain veneer in tension. The evolution of damage is followed with the aid of a video camera. The interfacial fracture energy G_C was determined with the aid of a FEA, taking into account the stress shielding effects due to the presence of adjacent channel cracks.

Results

Similarly to a previous study on PFZ specimens, the fracture sequence consisted of unstable growth of channel cracks in the veneer followed by stable cracking along the P/Z interface. However, the value of GC for the graded zirconia was approximately 3 times that of the control zirconia, which is due to the good adhesion between porcelain and the glass network structure on the zirconia surface.

Significance

Combined with its improved bonding to resin-based cements, increased resistance to surface damage and good esthetic quality, graded zirconia emerges as a viable material concept for dental restorations.

中文翻译：

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使用玻璃梯度氧化锆增加瓷/氧化锆牙科结构中的脱层生长阻力

客观的

融合至氧化锆（PFZ）修复体的瓷器广泛用于义齿牙科。但是，它们沿P / Z界面分层的趋势仍然是一个实际问题，因此评估和提高界面强度是重要的设计方面。这项工作研究了使用内部魔方玻璃修饰氧化锆贴面表面对熔融P / Z界面抗断裂性的影响。

方法

研究了三种材料系统：在有玻璃夹层的情况下和不存在玻璃夹层的情况下，与氧化锆熔合的瓷（对照）和与玻璃梯度氧化锆熔合的瓷。将样品装在四点弯曲的夹具中，使瓷贴面处于张紧状态。借助摄像机跟踪损坏的演变过程。考虑到由于相邻通道裂纹的存在而产生的应力屏蔽效应，借助于有限元分析法确定了界面断裂能G _C。

结果

与先前对PFZ试样的研究相似，断裂顺序由单板中通道裂纹的不稳定增长，沿P / Z界面的稳定裂纹组成。但是，梯度氧化锆的GC值约为对照氧化锆的3倍，这是由于瓷与氧化锆表面上的玻璃网络结构之间具有良好的附着力所致。

意义

结合改善的与树脂基胶粘剂的粘合性，增强的抗表面损伤性和良好的美学品质，梯度氧化锆已成为一种用于牙齿修复的可行材料概念。