Figure 6. Brittleness distribution for the young and old enamel.

The brittleness numbers in this figure were calculated according to Eqn. 1 using the H and E distributions obtained using nanoindentation (Fig. 3) and the K_c(app) distribution obtained using microindentation (Fig. 5). The region highlighted in gray represents the range in brittleness numbers obtained for the dental materials listed in Table 1. *The line denotes significant difference over the range in normalized distance covered. The p-value increases from left to right.