電気麻痺による新しい象牙質除痛法

Abstract

Various kinds of desensitizing method have been tried in case of the operation of the dentine which is highly sensitive. Recently the author devised a new and simple desensitizing method of dentine, “ELECTRO-ANESTHESIA”, only by means of weak direct current, and not by any anesthetica.PRINCIPLEIt has been well known that the direct current does not cause an irritation to the nerves, but causes the change in excitability while turning on a direct current, except when breaking or making the current, excitability increasing at the negative pole and its surrounding area while decreasing at the positive pole and its surrounding area (Electrotonus by Pfluger, 1859) . Application of this phenomena has been tried in anesthesia during minor operations at the end of the nineteenth century: A positive pole is fixed near to the operating field, while a negative pole is connected to the area far from the positive pole. Then a direct current is sent to both poles in order to decrease excitability of the operating field and to perform an electro-anesthesia and surgical operation.As the human body, however, is not so simple as a specimen of nerve and muscle, it is impossible to cause sufficient electrotonus jast at the operating field. Consequently this method could not be beyond the confines of theory and it has never been succeeded.Now the author devised a new method using a metallic surgical instrument as an electrode in order to obtain a successful electric potential in an operating field.TECHNICA positive pole from an electric source of D. C. is connected with an end of a handpiece and bur is used partly as an operating instrument during cavity preparation and partly as an electrode, while a negative pole, i.e., an indifferent electrode is connected, with the hand of a patient, (Fig. 3, 4.) . Then the routine operation is performed by a weak direct current such as about 4μA to 20μA being supplied from a D. C. source. (Fig. 5, 6.) .NOTICEThe following notices should be taken of:1. Decreasing an electric current, as we approach the, pulp chamber.2. Covering or painting a hand-piece and contra-angle with some isolating substances in order to keep from a leakage of the electric current.3. Keeping a good electric' connection between bur and hand-piece or contra-angle, using some kind of well-conducting lubricant, sich as potassium soap solution (10%) .4. Keeping a good electric connection between bur and tooth, using some harmless electrolytic solutions, such as procaine hydro-chloride etc..RESULT1) EffectOn 294 teeth of the 126 patients ( _??_59, _??_67, ) from 7 to 67 years, the author tried to make the cavity preparation by this method and obtained the following results: effective in 186 cases (91%) and ineffective in 18 cases (9%) .No case showed that the pain increased when the current had been on.2) Strength of the current which is effective to sud cient anesthesiaEach frequency curve expressing an effective strength of the current for anterior teeth, premolars, and molars (Figs, 8, 9, 10, ) did not show a normal form in distribution state. The curve for anterior teeth and premolars showed the maximum value at the point of 4μA., and that for molars showed two maximum values at the point of 4μA. and 10μA. It seemed that the curves of anterior teeth and premolars had possibility to show another maximum value at about 10μA.This technic can be applied not only to the dentin-desensitizing but also to anesthesia in case of incision of absesses, removal of serumal calculi, painful injections, and others.