 - subject age of 7 to 8 years, high caries risk evaluated by oral hygiene, dietary habits and fluoride exposure, according to Kidd 2011, with the first permanent molars without caries cavities, restorations, enamel defects, morphological anomalies andor signals of fluorosis. Subjects had to be willing to comply with all study procedures and protocols. They had to be residents of Ribeirão Preto or other nearby local communities with the same water fluoridation pattern to eliminate water fluoridation as a potential con- founding variable. Subjects had to be healthy and the parents or the child legal guardian need to be willing to sign the Authorization and informed consent for research form. There were no gender restrictions. 