Figure 3. Uptake of calcium ions from the upper solution by gelatin gel containing 1.5% amelogenin with (, sample) and without (, control) phosphate ions. Comparisons between the sample and the control for each measurement were made by Student’s t test, and statistically significant differences were defined at p < 0.05. Induction time was defined as the time when the comparison between the sample (phosphate-containing gel) and the control for each measurement was statistically significant. Values are based on ratio percentages of ⁴⁵Ca radioactivity (counts per min) at time t to that measured at time zero as the function of time. The data (13 points) shown are the mean ± SD of 3 separate experiments. The variability ranged between SD = 0.4–1.9 for control and SD = 0.3–2.3 for sample.