This article describes a novel approach to treat smooth-surface white spot lesions microinvasively. The technique is based on the infiltration of enamel caries lesions with lowviscosity light-curing resins called infiltrants. After the surface layer is eroded, the lesions are desiccated and a resin infiltrant is applied. The resin penetrates into the lesion microporosities driven by capillary forces and is subsequently hardened. Infiltrated lesions lose their whitish appearance and look similar to sound enamel. Additionally, the treatment prevents lesion progression. The proposed technique might be an alternative to microabrasion and restorative treatment, in particular for white spot lesions of esthetically relevant teeth. Keywords: caries, infiltrant, infiltration, penetration, resin, white spot