Initial caries is a condition in which minerals just below the surface of the tooth begin to dissolve and the tooth decreases in density. A tooth in this condition is one step away from developing a cavity. Initial caries can be treated by placing fluoride inside the tooth and promoting remineralization using minerals in saliva. One effective approach is to supply two kinds of fluoride together: sodium fluoride (NaF) and sodium monofluorophosphate (MFP). In normal toothpaste packaging, however, these two fluorides react with calcium-containing polishing agents, and this reduces their efficacy. Kao solved this problem by developing a dual-layered tube. The results of this work are seen in our Clear Clean Plus toothpaste.