Spectrophotometric evaluation of the effect of high noble, high-palladium and base metal alloys on the color of metal-ceramic restorations

Introduction: Color match between the restoration and the patient’s natural teeth has always been a source of concern in esthetic dentistry. One of the reasons for a lack of color match between the restoration and the natural teeth is the type of the alloy used in the metallic structure of the restoration. The aim of this study was to assess and compare the effect of 4 alloys on the color of the overlying porcelain: Degobond 4 from the high noble group, Begopal from the high-palladium group, and Super Cast and Minalux from the nickel-chromium base metal group. Materials and Methods: In this in vitro study, twenty disks, measuring 2 mm in thickness and 10 mm in diameter, were prepared (5 samples from each alloy). Then Vita 3DMaster 3M2 porcelain was placed on the samples. In addition, 5 control samples, measuring 2 mm in thickness, were prepared from the porcelain. A spectrophotometer was used to determine sample colors, which were evaluated based on CIELAB system. Data was analyzed with one-way ANOVA and Tukey test (α = 0.05). Results: The four alloys in this study exhibited significant differences in a* and b* values from the control group (p value < 0.001). The alloy groups did not exhibit any significant differences from each other in a* and b* values (p value > 0.05). There were significant differences in L* values between Supercast and Begopal (p value = 0.009) and between Begopal and the control (p value = 0.013) groups. There were no significant differences in ∆E between the alloys. Conclusion: The type of the alloy has an effect on the final color of porcelain; however, this color difference is clinically acceptable. Key words: Alloys, Color, Metal ceramic restorations, Spectrophotometry