ABSTRACT
The aim of this study was to compare the effectiveness of white mineral trioxide aggregate and gray mineral trioxide aggregate with different thicknesses and light curing glass ionomer cement when used as a barrier material in intracoronal bleaching procedures. In this study, 130 freshly extracted, caries free human permanent single rooted maxillary canine teeth were used. The teeth were randomly divided into six experimental groups, and positive and negative control groups. The specimens in the experimental groups 1, 2 and 3 received white mineral trioxide aggregate, gray mineral trioxide aggregate and light curing glass ionomer cement with a thickness of 2 mm, respectively. The specimens in the experimental groups 4, 5 and 6 received white mineral trioxide aggregate, gray mineral trioxide aggregate and light curing glass ionomer cement with a thickness of 5 mm, respectively. The positive control group received no barrier material and the negative control group did not undergo bleaching. There was no difference in leakage between gray mineral trioxide aggregate and white mineral trioxide aggregate (p>0.001). In conclusion, both gray and white mineral trioxide aggregate provided good coronal seal and decreased the amount of coronal leakage.