Sealing ability of MTA used as cervical barrier in intracoronal bleaching.

The aim of this study was to compare the sealing ability of white mineral trioxide aggregate (MTA) with that of other materials used as a cervical barrier during intracoronal bleaching. Thirty eight extracted teeth were endodontically treated and 3 mm of filling was removed to receive the barrier material: G1-Coltosol; G2 - Vidrion R; G3 - White MTA; G4-No barrier (negative control) and G5- Roots totally protected with three layers of cyanoacrylate (positive control). The 30% hydrogen peroxide associated with the sodium perborate was left in the pulp chamber for 24 h. The specimens were immersed in a test tube containing a solution of potassium chromate (yellow), which turns blue in the presence ofhydrogen peroxide. Two calibrated evaluators scored according to color in the presence of the detecting solution (0 - unaltered color, 1 - light blue and 2 - dark blue). Data were analyzed by the Kruskall-Wallis test (p<0.05). The results showed no statistically significant differences between the experimental group G3 and positive control (G5). No statistically significant difference was observed between G1 and G3. However a statistical difference was verified between G2 and G3. MTA presented higher sealing ability than Vidrion R and did not differ from the positive control. However there was no difference between MTA and Coltosol.