The aim of this study was to evaluate the remineralization of incipient carious lesions in bovine enamel in situ. Artificial carious lesions were produced and fixed in removable lower appliances in the region of the lingual surfaces of first molars, in six volunteers with ages between 18 and 22 years, who were subjected to 3 distinct experimental periods of 1 week each. In the first period (control group), patients brushed their teeth with a non-fluoridated dentifrice 4 times a day (after meals), and, in the second period (group I), patients used a dentifrice containing 1,500 ppm of fluorine (in the form of MFP). In the third period (group II) volunteers brushed their teeth with non-fluoridated dentifrice and used chewing gum containing 60% of sucrose during 20 minutes, 4 times a day (after meals). Before and after each treatment, the specimens underwent Vicker's hardness test (200 g of load), and the remineralization percentage (alpha) was calculated. The control group showed 2.78% of demineralization, and groups I and II showed 3.36 and 5.21% of remineralization, respectively. Statistical analysis (with Kruskal-Wallis and Miller's tests) showed significant difference (p < 0.05) between the control and experimental groups (I and II). Group II showed greater alpha than group I, but this difference was not significant. These results suggest that the use of sucrose-containing chewing gum and fluoridated dentifrice has a considerable effect on the remineralization of incipient carious lesions and may be a valuable alternative for their prevention.