Figure 2. Plot of volume % mineral vs. depth from the surface for 4 groups in a pH cycling study. Each group was treated between demineralization and remineralization by a dentifrice containing, respectively, (a) no added fluoride, (b) 250 ppm F, (c) 1100 ppm F, and (d) 2800 ppm F each as NaF. Error bars are standard deviations for the data at each depth from the surface. Each group is statistically significantly different from every other group (p < 0.05).