Application of titanium alloys to porcelain fuse to metal crown.

钛具有优良的性能，是一种很有吸引力的牙科修复材料，但铸造困难。我们一直在研究一些β稳定钛合金，它们的熔化温度低于纯钛。在牙科临床应用中，由于牙科美观的要求，这些合金必须能够粘结到牙科瓷器上。结果表明，Au-1.6wt%钛合金的热膨胀系数与常规贵金属烤瓷合金相近。Au-1.6wt%Ti合金的结合强度高于ISO 9693规定的最小值25兆帕。EPMA观察发现，在金属-陶瓷界面处，钛和氧在合金侧聚集。然后，我们研究了基牙光洁度对全冠适合性的影响。Au-1.6wt%钛合金烤瓷冠的铸造精度与常规贵金属合金铸造的精度相当。在铸造试件中，烤瓷的近中、远中边缘比唇缘和舌缘有更大的间隙。烤瓷面贴面类型的金属烤瓷冠，其边缘曲率越大，唇侧边缘间隙越大。Au-1.6wt%钛合金的铸造精度与对照贵金属合金相当。基牙光洁度对烤瓷冠边缘适合性有显著影响。

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.