Aim: Evaluating the remineralization efficacy of noncavitated proximal incipient lesions with Colgate® PreviDent® and MI™ varnishes in comparison to the industry standard (1.23%) acidulated phosphate fluoride (APF) gel. Study design: Parallel randomized controlled, multicenter, single-blinded trial. Materials and methods: By flipping a coin, 18 patients with 91 lesions were divided into three groups. The Colgate® PreviDent (n = 33), MI varnish (n = 30), and control (APF gel) groups (n = 28) were identified as the three arms. We conducted an initial assessment and therapy as well as follow-ups at 3 and 6 months to evaluate the course of the caries lesion. Results and statistics: Caries progression was significantly reduced on treated surfaces across both groups. Nine surfaces in the Colgate® PreviDent® group with white spots and dryness did not change, one surface turned into a white patch without dryness, and another surface changed to a sound surface; only two surfaces were discontinued from treatment (restored) due to a misdiagnosis by the operator (n = 2). Nine of the surfaces in the MI™ group maintained their white patches with dryness, whereas one developed a new white patch that was not dry. Only MI varnish™-treated teeth exhibited dramatic radiographic improvement. Caries on the outside enamel were either unchanged or restored to healthy levels. Caries on the inner surface of the enamel also did not change. Conclusion: Remineralizing noncavitated early-stage lesions may be done with both MI™ and Colgate® PreviDent® varnishes. Despite this, radiographic results did not vary significantly across the three groups. In situations of rather advanced incipient caries seen on radiographs, the MI varnish™ might be recommended.