Supplementary Figure 2: Time-lapse laser confocal microscopy images of dissolution process of regrown layer by our paste (a-c), and dental enamel (d-f) in acidic simulated saliva. Regrown layer and enamel are on the same tooth. Fig. 2g shows relationship between the change in depth by dissolution and time. Dissolution rate of re-grown layer is 5.0±0.5 m/h, lower than that of enamel, 6.5±0.6 m/h. Fig. 2h shows SEM photograph of longitudinal section of paste-treated tooth after 10,000 times of brushing. Loss of re-grown layer by brushing is less than 10 %.