This study was approved by the research ethics committee of School of Dentistry of University of Sao Paulo (Protocol# 1.981.756). The experimental design is in according to CONSORT. The present research will be a blind, parallel and randomized study with similar allocation between the treatment groups. It will be included 200 participants, selected among the patients of the Special Laboratory of lasers in dentistry (LELO-FOUSP). After being being informed of the objectives of the study the participants will be randomly divided into a treatment group (n = 25):