Histopathologic effects of electric dosage in iontophoresis on dental pulp

It is well recognized that dental pulp is very sensitive to electricity. However, the extent of damage and the repair capacity of pulp tissue after the electrical excitation of iontophoresis remains to be determined. Electrical current was applied to the simian teeth via cavities on the buccal or occlusal surfaces. The current strength was set at 0.1 mA-0.4 mA. The application duration was either 1 minute or 3 minutes. The total dose of electricity received by the iontophoresed teeth varied from 0.1 mA-minute to 1.2 mA-minutes. The pulps were microscopically examined at 4, 8, and 12 weeks after electrical excitation. All of the teeth were collected and processed using routine histologic methods. The following results were obtained: (1) in the group with 1-minute iontophoresis, the histologic pictures showed no apparent differences among the specimens regardless of the strength of the current applied; (2) in the group with 3-minute iontophoresis, the pulpal response correlated positively with current strength; and (3) with an electrical current of no greater than 0.4 mA and an application period of less than 3 minutes, the pulpal changes were reversible. We conclude that iontophoresis may accelerate the repair process, if the application duration is less than 3 minutes.