The randomization unit was the tooth, and the randomization procedure will be performed as follows. A number corresponding to each treatment group will be printed on pieces of paper and kept in dark containers. A paper will be selected from the container by a person other than the operator, and the treatment indicated will be performed (intervention/control). Blinding of the operator is not possible, because the color of intervention and control solution is different. The operator is blinded until randomization into groups, to avoid biases with regard to the application of antibacterial agent. Also, the examiner who will carry the microbiological analysis of dentin samples will be blinded to the type of agent applied during treatment. Finally, the treatment results will be assessed blindly by a statistician.