Dentifrices have been recognized as one of the contributors in the increased prevalence of dental fluorosis, due to the fact that children in early childhood usually eat lots of them during brushing. As an alternative to the reduction of fluorosis have been suggested to reduce the concentration of fluoride toothpaste, however, its efficacy is not well established, increasing when the pH of the toothpaste is acidic, with a greater diffusion of F in the enamel. Therefore, this study aims to assess the overall effect of pH and fluoride concentration of liquid dentifrices in the control of children dental caries of a fluoridated area. A randomized double-blind study will be conducted with approximately 360 children aged 2 to 4 years old at public daycare centers located in a fluoridated area. Children will be examined by two examiners and classified according to caries activity. For 12 months, children will use 3 times a day, one of the toothpaste to be tested, with different concentrations of fluoride and pH. At the end of this period, children will be examined by the same examiners to check the progression of lesions. Clinical examinations should be performed by 2 calibrated examiners (kappa 0.8) at baseline and after 12 months. The diagnostic criteria of caries activity (active, inactive) and integrity of the surface of the lesion will be used. There will be a quantitative assessment of carious lesions fluorescence with a portable QLF equipment. In half of the sample, nails and plaque will be collected 6 months after initiation of the dentifrices use. Samples of plaque will be analyzed for fluoride using an ion-specific electrode after diffusion with hexamethyldisiloxane-facilitated disiloxane (HMDS). The presence of nails F will be analyzed as described above. For statistical analysis will be used ANOVA and test for individual comparisons.