Experimental Study on the Pulp Treatment by Means of High Frequency Current (Animal Experiment)

Abstract

Tried pulpamputation or pulpextirpation on totally 132 cases of dog's teeth in situ by means of short waves (wave length 13 m) or diathermy current (wave length 158 m) and the effects of the high frequency current, in surgical application, on the pulp and the periodontal tissue were histologically observed.
The results were as follows.
1) When the active electrode was inserted into the pulp and the pulp was amputated at the portion of the extremity of the electrode, where the coagulation of the pulp tissue was expected, it was observed in many cases that the rest of the pulp was fallen into the retrogressive degeneration, reticular atrophy for example.
2) When spark discharge was made to form a thick layer of the coagulated tissue over the wound of the amputated pulp, the tissue under the layer was kept almost intact. Even in short elapse, there, observed a very slight inflammatory symptoms; hyperaemia and round cell infiltration. And the wound was soon healed in forming a hard tissue under the coagulated layer.
3) Pulp coagulation was caused in bifurcated root canals when the electrode was inserted as far as the apex. The remnant pulp in contact with the coagulated tissue in the bifurcated root canals and the periapical tissue showed a very slight inflammatory changes and the border regions of the coagulated tissue were healed in a scar or in a osseous scar.
4) In performing pulpextirpation applying high frequency current it is desirable to leave a layer of the coagulated tissue at the wound surface. Quantity of the coagulated tissue left, has little influence upon healing of the periodontal tissue.
5) When electrifying the high frequency current, necrosis due to a burn could be easily caused in cementum, periodontal membrane and alveolar bone etc. These necrotic tissues were absorbed and replaced with a newly formed osseous tissue and the ankylosiss between the root and the alveolar bone was occurred. These changes were observed in 75 per cent of the cases of coagulating pulpextirpation.
6) The severest burn was observed in periodontal tissue at the extremity of the electrode and in the case of diathermy was observed frequently, in the environs of the root and often, at the cervical region only. In general, a burn is apt to be caused at the regions where the canal wall is comparatively thin.
7) To prevent the periodontal tissue from a burn, it is considered that the duration of electrification should be within 1 sec. for the purpose of decreasing a thermal conduction from the interior of the canal and the usage of spark discharge at the same time will be recomenderable.