Application of titanium alloys to porcelain fuse to metal crown.

钛因其优良的性能而成为一种极具吸引力的牙科修复材料，但其铸造困难。我们一直在研究一些β稳定的钛合金，它们的熔化温度比纯钛低。为了满足牙科临床应用的美学要求，这些合金必须能够与牙科陶瓷结合。结果表明，Au-1.6 wt% Ti合金的热膨胀系数与传统贵金属合金的热膨胀系数相近，与金属烤瓷冠的结合强度和适合性相近。Au-1.6重量% Ti合金的结合强度高于25 MPa，即ISO 9693中规定的最小值。电子探针分析显示，在金瓷界面处，钛和氧的含量在合金侧有一定的积累。结果表明，Au-1.6 wt% Ti合金铸造的金属烤瓷冠与传统贵金属合金铸造的金属烤瓷冠相比，具有良好的精度。Au-1.6wt% Ti合金与对照贵金属铸造的瓷冠边缘密合性相当，基牙终饰线曲率对瓷冠边缘密合性有显著影响。

Titanium is an attractive dental restorative material because of its excellent characteristics, however it is difficult to cast. We have been investigating some beta-stabilized titanium alloys which have lower fusion temperatures than pure titanium. For dental clinical use, these alloys must be able to bond to dental porcelains because of the esthetic demands of dentistry.This time, we investigated the Au-1.6wt% Ti alloy. The bond strength to porcelain and fitness of porcelain fused to metal crown were evaluated.The coefficient of thermal expansion of the Au-1.6 wt% Ti alloy showed a close value to that of conventional precious metal alloys for porcelain fused to metal crown. Bonding strength of the Au-1.6 wt% Ti alloy was higher than 25 MPa, the minimum value specified in ISO 9693. EPMA observation showed an accumulation of Ti and O contents on the alloy side at the metal-ceramic interface.Then we investigated the effect of abutment finish-line curvature on the fit of crowns. The metal ceramic crowns cast in Au-1.6 wt% Ti alloy had accuracy as good those as-cast in control of conventional precious metal alloys for porcelain fused to metal crown.In the as-cast specimens, the greater the finish line curvature, the mesial and distal margins of copings exhibited larger gaps than labial and lingual margins.After porcelain application, for metal ceramic crowns of the facial-veneered type, the greater the finish line curvature, the larger the labial marginal gap became.Au-1.6wt% Ti alloy had equivalent accuracy to those that cast in control precious alloy, and the abutment finish-line curvature had a significant effect on the marginal fit of porcelain fused to metal crowns.