Effectiveness of cervical bases in the intracoronal bleaching

Discoloration of nonvital teeth is aesthetic deficiency frequently requiring bleaching treatment. Objectives:The purpose of this study was to evaluate in vitro the cervical bases efficacy, in order to prevent or to minimize the leakage along the root canal filling and into the dentinal tubules. Methods: Thirty-eight extracted single-root human teeth were used, which were biomecanically prepared, filled and divided into 3 experimental groups (12). G1: a cervical base was accomplished (3mm of thickness), up to the cementoenamel junction, with resin-modified glass-ionomer cement (Vitremer); G2: the base was accomplished with glass-ionomer cement (Vidrion R) and G3 (Control): did not receive any material as base. A mixture of sodium perborate and hydrogen peroxide 30% was placed inside the pulp chamber for 3 days and the access opening sealed with Cimpat. This procedure was repeated twice. Soon after, a paste of calcium hydroxide was inserted in the pulp chamber for 14 days. All teeth were covered with two layers of sticky wax, except the access opening, and immersed in blue India Ink for 5 days. Results: The results showed no statistically significant differences between the 3 groups concerning the leakage inside the dentinal tubules, however, in apical direction, there was statistical difference (ANOVA p<0,05) between the experimental and control groups and there was no statistical difference among the experimental groups G1 and G2. Conclusions: it is recommended the placement of a cervical base (glass ionomer cement or resin-modified glass-ionomer cement) before intracoronal bleaching procedures.