Histopathologic effects of various electric dosage on the dental pulp of the monkey with iontophoresis.
Iontophoresis may enhance the efficacy of some medicaments and help them to reach inaccessible parts of the treated area. However, the extent of tissue damage and its recovery after electric excitation remain to be determined. An animal experiment was performed to find out the proper combination of electric current and applied duration in iontophoresis that did no irreversible harm to the pulp tissue. Cavities of 2mm in diameter and 1-2mm in depth were prepared on the buccal or occlusal surfaces of the teeth of monkeys. The strength of electric current was regulated to 0.1 mA, 0.2 mA, 0.3mA and 0.4 mA, respectively. The applied duration was 1 or 3 minutes. The total amount of electricity received by the iontophoresed teeth varied from 0.1 mA-min to 1.2 mA-min in dosage. Observation was made at 4 weeks, 8 weeks and 10 weeks after experiments. The teeth, including the surrounding jaw bone, were resected and prepared for histopathologic study. The following results were obtained: (1) In the group with one-minute iontophoresis, the histologic pictures showed no apparent difference among the specimens regardless of the strength of the electric current applied and were similar to that of the control group. (2) In the group with 3-minute iontophoresis, pulp response correlated with an increase in the electric current applied. (3) Obvious histopathologic changes were shown in the 4-week specimens, mostly odontoblast disruption, vascular dilatation, hemorrhage and round cell infiltration. (4) Subsequent investigation of the 8-week specimens as well as the 10-week specimens revealed that the reparative process in the damaged pulp took a lot of time to heal.
Lan
W H
WH
D000818:Animals; D003731:Dental Caries / Q000473:pathology; D003782:Dental Pulp / Q000473:pathology*; D004560:Electricity; D007478:Iontophoresis; D008251:Macaca; D013997:Time Factors