All study participants must have two early class V carious lesions in need of a treatment but not of an invasive treatment (split-mouth design). One lesion will be treated with Curodont Repair and one with placebo as control (single application). 3 months later fluoride (Duraphat) will be applied on both lesions. Study duration is 9 months. For assessment visual and tactile evaluation, pictures, ECM, Diagnodent Pen, Canary System, VAS is used.