Konstantoulakis E, Nakajima H, Woody R D, Miller A W
Texas A&M University System--Baylor College of Dentistry, Dallas, USA.
J Prosthet Dent. 1998 Sep;80(3):337-45. doi: 10.1016/s0022-3913(98)70135-0.
Conventional investing and casting techniques following the manufactures' recommendations are time-consuming. Accelerated casting techniques have been reported, but their accuracy has not been adequately studied for complete crown castings.
This study evaluated the marginal fit and surface roughness of complete crowns made with a conventional and an accelerated casting technique.
Part I of the study determined the mean time interval required for each investment to reach its maximum exothermic setting reaction temperature. Part II determined the marginal discrepancy of standardized complete crowns cast in a high noble metal ceramic alloy, with the use of four phosphate-bonded investments. A conventional technique (as recommended by the manufacturer) was compared with an accelerated technique that used 13- to 17-minute bench set time (as determined in part 1 for each investment)_ and 15-minute wax elimination cycle in a 815 degrees C (1500 degrees F) preheated furnace. Part III evaluated the surface roughness of castings made with the same techniques as in part II.
For the marginal discrepancy and surface roughness, crowns fabricated with the accelerated casting technique were not significantly (P > 0.05) different from those fabricated with the conventional technique.
The accelerated casting technique described in this study could be a vital alternative to the time-consuming conventional techniques.
遵循制造商建议的传统包埋和铸造技术耗时较长。已有加速铸造技术的相关报道，但对于全冠铸造，其准确性尚未得到充分研究。
本研究评估了采用传统铸造技术和加速铸造技术制作的全冠的边缘适合性和表面粗糙度。
研究的第一部分确定了每种包埋材料达到其最大放热凝固反应温度所需的平均时间间隔。第二部分确定了使用四种磷酸盐结合包埋材料铸造的高贵金属烤瓷合金标准化全冠的边缘差异。将一种传统技术（制造商推荐的）与一种加速技术进行比较，加速技术采用13至17分钟的台架凝固时间（由第一部分针对每种包埋材料确定）以及在815℃（1500°F）预热炉中的15分钟除蜡周期。第三部分评估了采用与第二部分相同技术制作的铸件的表面粗糙度。
对于边缘差异和表面粗糙度，采用加速铸造技术制作的全冠与采用传统技术制作的全冠无显著差异（P>0.05）。
本研究中描述的加速铸造技术可能是耗时的传统技术的重要替代方法。
