Gardner F M, Tillman-McCombs K W, Gaston M L, Runyan D A
Medical College of Georgia, Augusta, USA.
J Prosthet Dent. 1997 Jul;78(1):1-4. doi: 10.1016/s0022-3913(97)70079-9.
This in vitro study compared the load necessary to cause porcelain failure on traditionally fabricated metal-ceramic crowns cemented to metal tooth analogs with two different types of margins.
Metal-ceramic crowns were constructed with either metal facial collars or porcelain facial margins. The metal tooth analogs were embedded in polymethyl methacrylate resin blocks, so that a load applied to the lingual surface compressed the facial margins. Increasingly greater loads were applied to specimens until failure occurred and the failure load values of all specimens were statistically evaluated.
The load required to cause porcelain fracture in the crowns with porcelain facial margins was statistically significantly greater than the load required to cause porcelain fracture for crowns with metal collars (p < 0.02).
本体外研究比较了粘结在具有两种不同边缘类型的金属牙代型上的传统制作的金属烤瓷冠发生瓷层崩裂所需的负荷。
制作具有金属唇侧边缘或瓷唇侧边缘的金属烤瓷冠。将金属牙代型嵌入聚甲基丙烯酸甲酯树脂块中，使得施加于舌面的负荷压缩唇侧边缘。对试件施加逐渐增大的负荷直至发生崩裂，并对所有试件的崩裂负荷值进行统计学评估。
具有瓷唇侧边缘的冠发生瓷层崩裂所需的负荷在统计学上显著高于具有金属边缘的冠发生瓷层崩裂所需的负荷（p < 0.02）。
