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A Comparison of the Marginal Accuracy of Metal Copings Made with Three Different Brands of Nickel–Chromium Alloys and Various Sprue Designs: An Vitro Study

Introduction: It is important to construct the sprue in a way that ensures that the mold gets an appropriate supply of metal at the right speed. Many manufacturers now offer sprue designs that have not been advocated in textbooks or publications for their normal use. Aim: The goal of this research was to compare the sprue design's marginal fit to that of the other designs. Methods: During this investigation, we attempted to see whether the fabrication of metal copings could be improved. Three sprue designs were used in this research for the assessment of casting accuracy: normal cylindrical, funnel-shaped, and cuboidal or flattened sprue forms. Results: The mean marginal disparity of nickel–chromium (Ni–Cr) alloy copings made by three distinct brands was determined to be statistically insignificant. Conclusion: Within the limitation of the study, it was concluded that the marginal accuracy of metal copings fabricated with three different brands of Ni–Cr alloy did not reveal a statistically significant result. However, out of the three different sprue designs, that is, cylindrical, cuboidal, and funnel shape, the marginal accuracy of cylindrical and cuboidal sprue designs was found to be better than that of the funnel shape sprue design because the funnel shape sprue design is narrow at the point of attachment, thereby increasing the flow pressure and decreasing the turbulence of the molten metal.