Morey E F, Earnshaw R
Department of Operative Dentistry, University of Sydney, Surry Hills, NSW, Australia.
J Dent Res. 1992 Dec;71(12):1858-64. doi: 10.1177/00220345920710120101.
Measurements were made of the fit of full-crown gold-alloy castings produced with two types of pre-wetted ring liner (asbestos and cellulose) and a typical gypsum-bonded investment (Cristobalite Inlay, Sybron/Kerr Products, Romulus, MI; W/P = 0.40). Laboratory measurements were made of the effects of the liners on potential investment expansion, and properties of the lining materials considered relevant to casting accuracy were also measured. There was a wide variation in values for mean dimensional inaccuracy. One liner produced a series of castings all of whose inaccuracies lay within the range +/- 0.1%, with a mean value of + 0.01%. With the other five liners, all or most castings were undersize. With three, all or most castings showed inaccuracies worse than -0.2%. The values for casting inaccuracy with the various liners showed a probable correlation with potential investment expansion (p < 0.05); however, no correlation was found between casting inaccuracy and any apparently relevant liner properties, alone or in combination. In casting techniques which use a pre-wetted ring liner, the choice of a specific lining material is an important factor which has a significant effect on casting inaccuracy. With at least three of the six liners tested, a higher investment expansion was needed for accurate full-crown castings to be ensured.
对使用两种预湿铸圈衬里（石棉和纤维素）以及一种典型石膏粘结包埋材料（方石英嵌体，Sybron/Kerr产品，密歇根州罗穆卢斯；水/粉比=0.40）制作的全冠金合金铸件的贴合度进行了测量。对衬里对潜在包埋材料膨胀的影响进行了实验室测量，还测量了与铸造精度相关的衬里材料性能。平均尺寸误差值存在很大差异。一种衬里制作的一系列铸件，其所有误差都在±0.1%范围内，平均值为+0.01%。使用其他五种衬里时，所有或大多数铸件尺寸过小。使用三种衬里时，所有或大多数铸件的误差超过-0.2%。使用各种衬里时的铸造误差值与潜在包埋材料膨胀可能存在相关性（p<0.05）；然而，未发现铸造误差与任何单独或组合的明显相关衬里性能之间存在相关性。在使用预湿铸圈衬里的铸造技术中，选择特定的衬里材料是一个重要因素，对铸造误差有显著影响。对于测试的六种衬里中的至少三种，需要更高的包埋材料膨胀才能确保全冠铸件的准确性。
