The purpose of this study was to evaluate the difference in mineral loss of incipient enamel artificial carious lesions that were sealed with fluoride- or nonfluoride-containing resin sealant. Two artificial lesions (2x2 mm2 each) were created on buccal surface of 60 premolars by using Carbopol demineralizing solution. Lesions in the first group (30 teeth) was sealed with Delton and Delton Plus, the second group (30 teeth) was sealed with Helioseal and Helioseal F. All teeth were immersed in artificial saliva for 7 days and sectioned through the lesions. The cross-sectioned surfaces were polished and then subjected to Vickers hardness measurement at 20 mm from the resin-enamel interface, and every 10 mm inwards across the lesion to the underlying sound enamel. Mineral content was converted from hardness number. Mean mineral loss was calculated and was compared between lesions sealed with fluoride- or nonfluoride-containing sealants. Mean +/- SD of mineral loss for Delton, Delton Plus, Helioseal and Helioseal-F were 1423 +/- 441, 1287 +/- 421, 1223 +/- 284, and 1165 +/- 267 VPM*mm, respectively. Paired t-test showed that the mineral loss of incipient enamel carious lesions sealed with fluoride-containing sealants, Delton Plus and Helioseal-F were not significantly different from those of nonfluoride-containing sealants, Delton and Helioseal (P > 0.05).