THE EFFECT OF INVESTMENT TYPE ON THE FIT OF CAST TITANIUM CROWNS
THE EFFECT OF INVESTMENT TYPE ON THE FIT OF CAST TITANIUM CROWNS
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DOI：
10.1111/j.1834-7819.1994.tb03104.x
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发表时间：
1994-12-01
影响因子：
2.1
通讯作者：
TOGAYA, T
中科院分区：
文献类型：
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作者：
MORI, T;JEANLOUIS, M;TOGAYA, T
为了确定钛冠铸造的最佳实验室程序，使用铸造机（氩气，压差型）和三种不同的包埋料（两种传统的SiO2基包埋料和一种新的Al 2 O（3）/MgO基包埋料）进行了一组热膨胀测量和铸造实验。热膨胀测量涉及加热和冷却的循环。对于传统的包埋件，推荐的（200 ℃）或选择的（350 ℃）相对较低的模具温度提供了零或负的模具膨胀，以补偿金属收缩。由这些包埋料制成的牙冠与模具发生了严重的反应，因此喷砂的常用清洁方法显得至关重要。然而，这种清洁过程不足以评估铸造精度，因为短喷砂时间（15秒）迅速改变了牙冠的适合性。金属与新的包埋料几乎没有反应，并且当包埋料被加热到950摄氏度，然后冷却到推荐的模具温度（600摄氏度）时，实现了对金属收缩的最佳补偿（0.15 mm差异），如“铸态”评估的。
In order to determine the best laboratory procedure for titanium crown casting, a set of thermal expansion measurements and casting experiments were carried out using a casting machine (argon are, pressure difference type) and three different investments, two conventional SiO2 based investments and a new Al2O(3)/MgO based investment. The thermal expansion measurements involved a cycle of heating and cooling. The relatively low mould temperatures recommended (200 degrees C) or chosen (350 degrees C) for the conventional investments provided zero or negative mould expansion for the compensation of metal shrinkage. Crowns made from these investments exhibited heavy reaction with the mould, and the common cleaning method of sand blasting appeared to be essential. This cleaning process, however, was not adequate for the assessment of casting accuracy as the short sand blasting time (15 s) rapidly altered the fit of the crowns. The metal reacted little with the new investment and the best compensation (0.15 mm discrepancy) for the metal shrinkage, as assessed 'as cast', was achieved when the investment was heated to 950 degrees C and then cooled to the recommended mould temperature(600 degrees C).