An in Vitro Comparison of Coronal Discolouration Caused by White Mineral Trioxide Aggregate, Theracal, Calcium-Enriched Mixture and Biodentine

Objective: The use of calcium silicate-based cements has greatly increased in the past decade. This study compared coronal discolouration caused by white mineral trioxide aggregate (MTA), TheraCal (TC), calcium enriched mixture (CEM), and Biodentine (BD) on bovine enamel-dentin block. Methods: In this in vitro, experimental study, enamel-dentin blocks (7x7x3.5 mm) were cut out of 60 extracted sound bovine central incisors. A cavity (2.5 mm diameter and 1 mm depth) was created at the center of each block with 1 mm distance from the labial surface. The blocks were randomly divided into four experimental groups (n=12) of MTA, CEM, BD, and TC and two groups of positive (blood) and negative (empty) controls. After filling cavities with experimental materials, the surfaces of the materials were covered with composite resin. The colour parameters were measured using a spectrophotometer, before (T0) and 1 week (T1), 1 month (T2), and 6 months (T3) after the application of the materials. The data was analysed using repeated measures ANOVA and the Kruskal-Wallis test. Results: At 1 week and 1 month, a significant difference in ∆E was noted in the control groups compared to the experimental groups (P<0.001). The difference among the four cements was not significant (P=0.06) at 1 week but it was significant at 1 month. TC showed greater ∆E whereas BD showed lower ∆E in the six-month period (P<0.001). Colour change was significant over time in the MTA and TC groups (P<0.05). Conclusion: TheraCal caused greater discolouration in the bovine tooth blocks after 6 months, which may make it inappropriate for application in the aesthetic zone.