RESUMEN
Color matching, visual combination and accurate shade selection with natural teeth are important issues in restorative dentistry. In ceramometal restorations, the type of substructure alloy affects the final color of bonded porcelain. Minalux alloy, is the most commonly used Iranian product which is a base metal alloy [Ni-Cr]. The aim of this study is to compare the effect of three base metal alloys [Wirron 99, Bellabond and Minalux] on their masking of porcelain color and to assess various color dimentions between them. In this in vitro study, ten disks, approximately 0.3 mm thick and 1 cm diameter, were prepared from each alloy. Then a 1 mm thickness layer of vita VMK68 porcelain shade A[2] was baked onto them, following the manufacture's instruction. Ten samples with 5 mm thickness were prepared from the same porcelain and designated the "control group". All samples, with similartining and in similar conditions of environmental light were assessed by a computer colorimetry instrument; and color values such as 1*, a* and b* under CLE-LAB system were measured. The data were analyzed by one-way-Anova and Tukey tests. Three alloys in this study as compared with the control group, had significant effect on the three variables 1*, a* and b* [respectively P=0.004, P=0.037, P<0.001]. In these alloys, Wirron 99 and Bellabond, had significant difference on the two variables l* [P-value=0.025] and a* [P-value=0.037]; but Minalux alloy did not have any significant difference with other groups. The comparison between the average of deltaE quantities alloys, indicated that the difference of Vita porcelain shade A[2] baked on Wirron 99 and Bellabond was significant. The effect of Iranian minalux alloy on color's parts and it's related deltaE quantity, is in a similar range of two foreign alloy products Wirron 99 and Bellabond