Figure 3. Log FTIR intensity ratios of amide I to HPO₄^2– showing the mineral content of restored enamel and restored root surface with 3 different restorative materials (scan area: 100 x 100 µm) (n = 5 for each restorative tested). The log [amide I:HPO₄^2–] for glass-ionomer cement was lower than that of the other 2 materials (P = 0.04). The statistical analysis of the restorative materials (v1) was: Type III sum of squares = 0.90, df = 2, mean square = 0.45, F = 4.19, and sig. = 0.03. The statistical analysis of sound and demineralized tissue (v2) was: Type III sum of squares = 0.51, df = 1, mean square = 0.51, F = 4.69, and sig. = 0.03. The statistical analysis of v1*v3 was: Type III sum of squares = 0.07, df = 2, mean square = 0.03, F = 0.32, and sig. = 0.73.