Color Analysis of Metal Ceramic Restorations Fabricated from Different Dental Laboratories

Objective: The aim of the present in vitro study was to explore the differences in color matching of most frequently used shades for metal ceramic dental restorations fabricated by different laboratories. Materials and Methods: A total sample size of 180 discs of metal ceramic were prepared by six laboratories (labs): each lab prepared 30 samples, 10 for each shade (A1, B1, and C1). Instructions for standardization were provided. A spectrophotometer and CIE LAB system was used to find ∆E value for difference between shades observed by spectrophotometer. For statistical analysis, ANOVA and post hoc Tukey tests were used. Significance level was <0.05. Results: Significant variation (p = 0.000) was observed among the labs for ∆E. The maximum value for ∆E in shade A1 was 77.0 ± 0.065 and minimum value for ∆E noted for shade A1 was 69.19 ± 1.39. The values of ∆E for shade B1 were maximum 80.14 ± 0.16 and minimum 68.38 ± 0.40 and the values of ∆E for shade C1 were maximum 80.16 ± 0.14 and minimum 71.62 ± 1.23. Twelve out of 15 comparisons between labs for shade A1, 14 of 15 comparisons for shade B1, and 11 of 15 comparisons for shade C1 showed significant difference (p = 0.000). Conclusions: Similar tooth shades (A1, B1, and C1) when duplicated by different labs exhibited highly significant color variations.