Figure 5.

Alkaline phosphatase activity (ALP) of human osteoblasts growing on electrodes (a) and coverslips (b) with and without electrical stimulation. Results are displayed relative to the unstimulated controls after one, three, and seven days. For this experiment, 0.2 V, 1.4 V, and 2.8 V groups were stimulated 3 × 45 min per day, while the cont. 1.4 V group was stimulated continuously with 1.4 V. # indicates significant differences between the stimulated and control groups: # p < 0.05 and ## p < 0.01 (Wilcoxon matched pair test), * indicates significant differences between stimulation groups: * p < 0.05, ** p < 0.01, *** p < 0.001 and **** p < 0.0001 (two-way ANOVA). n ≥ 3.