Permeability Evaluation of Different Isolating Materials in Internal Bleaching

Objective: this study evaluated the permeability of different isolating barriers used in non vital tooth bleaching. Methods: forty human canines were endodontically prepared and filled with gutta-percha and Sealer 26 cement, and subsequently divided into 4 groups (n=10). After 7 days, 3 groups were randomly selected and 2mm of the filling material were removed. This place was filled with different isolating materials: Group 1 – low viscosity composite, Group 2 – resin modified glass ionomer cement and Group 3 – zinc phosphate cement. In the control group (Group 4), the filling material was maintained at the cementoenamel junction (CEJ) level. The roots were externally covered with nail varnish 2mm below the CEJ, and a 35% hydrogen peroxide gel (HP) was placed into the pulp chamber, and soon after this, sealed with composite resin. Immediately, the roots were immersed in a solution containing 0,1M potassium iodide and starch saturated agar-agar. When in contact to HP, this solution turned to dark blue, indicating that the peroxide passed through the tooth structure. After 24 hours, the teeth were photographed and the halos areas were measured in the Image Tools software. Results: data were submitted to Kruskal-Wallis test (p=0.1). The groups G2, G3 and G4 were similar and performed better than G1. Conclusion: low viscosity resin showed inferior behavior when compared to the other materials tested.