Ramesh Ganesh, Padmanabhan T V, Ariga Padma, Subramanian R
Department of Prosthodontics, Sree Balaji Dental College and Hospital, Chennai, India.
Indian J Dent Res. 2011 Sep-Oct;22(5):733. doi: 10.4103/0970-9290.93471.
Since 1907 casting restorations have been in use in dentistry. Numerous companies have been manufacturing and marketing base metal alloys. Gold was a major component of casting alloys. But alloys with less than 65% gold tarnished easily and the increase in cost of gold post-1970s lead to the revival of base metal alloys such as nickel-chromium and cobalt-chromium alloys which were in use since 1930s.
This study was conducted to evaluate and compare the castability between an indigenous alloy and an imported alloy, as imported base metal alloys are considered to be expensive for fabrication of crowns and bridges.
This study was conducted to evaluate and compare the castability (for the accurate fabrication of crowns and bridges) between an indigenous base metal alloy-Non-ferrous Materials Technology Development Centre (NFTDC), Hyderabad (Alloy A) -and an imported base metal alloys (Alloy B). Castability measurement was obtained by counting the number of completely formed line segments surrounding the 81 squares in the pattern and later calculating the percentage values. The percentage obtained was taken as the castability value for a particular base metal alloy. The percentage of castability was determined by counting only the number of completely cast segments in a perfect casting (81 × 2 = 162), and then multiplying the resulting fraction by 100 to give the percentage completeness.
The Student t-test was used.
When the castability of alloys A and B was compared, the calculated value was less than the tabular value (1.171 < 2.048) leading to the conclusion that castability between alloys A and B is insignificant. Therefore we conclude that both the alloys have the same castability.
Using the above-mentioned materials and following the method to test castability, we were able to derive favorable results. As the results were satisfactory, we can conclude that the castability of the indigenous alloy is on par with the imported alloy.
自1907年以来，铸造修复体一直在牙科中使用。许多公司一直在生产和销售贱金属合金。黄金是铸造合金的主要成分。但含金量低于65%的合金容易 tarnished（原文此处可能有误，推测应为“变色”之类的意思），20世纪70年代后黄金成本的增加导致了自20世纪30年代以来就一直在使用的贱金属合金如镍铬合金和钴铬合金的复兴。
本研究旨在评估和比较一种国产合金与一种进口合金之间的铸造性能，因为进口贱金属合金被认为用于制作冠和桥的成本过高。
本研究旨在评估和比较一种国产贱金属合金——位于海得拉巴的有色金属材料技术开发中心（NFTDC）（合金A）与一种进口贱金属合金（合金B）之间的铸造性能（用于精确制作冠和桥）。通过计算图案中围绕81个方格的完全形成的线段数量，然后计算百分比值来获得铸造性能测量结果。所获得的百分比被视为特定贱金属合金的铸造性能值。铸造性能百分比仅通过计算完美铸件（81×2 = 162）中完全铸造的线段数量来确定，然后将所得分数乘以100以得到完整百分比。
采用学生t检验。
比较合金A和合金B的铸造性能时，计算值小于表格值（1.171 < 2.048），得出合金A和合金B之间的铸造性能无显著差异的结论。因此我们得出结论，两种合金具有相同的铸造性能。
使用上述材料并遵循测试铸造性能的方法，我们能够得出良好的结果。由于结果令人满意，我们可以得出国产合金的铸造性能与进口合金相当的结论。
