 The literature recognizes that fluoride is the most widely used and studied means for dental remineralization. The use of fluoride toothpaste in brushing is considered more rational method for the prevention of caries. However, the current challenge of toothpaste is the substantivity, so new compounds have been introduced into these formulations. This study aims to evaluate the in vivo effect of fluoride dentifrice containing nanoencapsulated Fluoride Nano-F - in fluoride retention in saliva and dental plaque. A study of the clinical and laboratory type, crossover, double-blind, randomized will be held. After sample calculation, the total of 12 individuals aged between 18 and 35 years old, healthy, decayed, missing, and filled teeth index less than 6 and residents in brazilian northeast capital will be part of the sample. Fluoride bioavailability will be evaluated in the biofilm and saliva after the use of fluoridated weekly. The biofilm will be assessed on 1h and 12 h after brushing; and unstimulated saliva in times of 3, 15, 30, 45, 60 minutes and 12 hours after. It will be 3 toothpastes: 50 Nanoencapsulated Fluoride, 100 Nanoencapsulated Fluoride and Free sodium fluoride. Between weeks of use, brushing will be extended washout without fluoride to avoid carryover effect. inferential data analysis will be carried out, considering the amount of alpha 0.05. So knowing that caries is a dynamic process, the largest fluoride retention in the oral fluids promoted by the Nanoencapsulated Fluoride may have important impact on Des-Re process and in the control of dental caries 