Eberhart's Manual of High Frequency Currents
Noble M. Eberhart, M.D., Ph.D., D.C.L., 1911
High Frequency in Dentistry.
General Field of Usefulness. High frequency currents are coming
daily into more and more frequent use by dentists. They are employed in pyorrhea, in
drying cavities, in devitalizing teeth, in sterilizing root-canals, in bleaching teeth, in
abscesses, in locating devitalized teeth, and for the relief of pain. The author is not a
dentist, but has tried to give in this chapter a resume of current dental opinion and
technique as gathered from various sources. Several dental electrodes are illustrated in
Pyorrhea. Pyorrhea early manifests itself by a
light reddening of the gums at the margins and a tendency to bleed on slight provocation.
A large majority of patients having pyorrhea are anemic, and in these the gums, instead of
being red, may have a yellow and discolored appearance and are apt to be flabby or
receding instead of puffy. In the second stage of the disease, pus appears, attacking
first the peri-dental membrane. Later the bony socket of the tooth may be slowly eaten
away or destroyed. The gums gradually recede and the tooth becomes loose in its socket and
painful to the touch.
From this we can see at once indications for the
employment of high frequency currents.
A french authority says that it is necessary "to
destroy the microbic and suppurative state of the gums, correct the depleted nutrition in
the tissue and produce an over-active phagocytosis and increase the index of leucocytic
destruction. For this result one uses high frequency currents with the greatest success in
the two forms, the effleuve (spray) and the spark."
Gremeaux and Arnal (l'Est Dentaire, Sept., 1913) use
the high frequency as follows; "One introduces the metallic fulguration electrode as
far as possible between the loosened gum and the tooth, in order that the spark may reach
all the recesses and purulent foci. During the operation, which lasts an average of a
minute for each tooth, one sees the margin of the gum blanch and the pus bubble out at the
neck of the tooth. When all of the recesses have been penetrated, the fulguration point is
replaced by a small vacuum electrode, which is passes over the external and internal
surface of the gums for about ten minutes."
They wait three or four weeks to note results before
giving a second treatment, employing a rigorous antiseptic regime in the meantime,
consisting in brushing with an alkaline powder night and morning, and numerous rinsings
with boiled water, etc. About a week after the treatment the patient massages the gums
with the finger twice a day. In three or four weeks, if pressure on the gum shows presence
of pus, the treatment is repeated; otherwise the case is dismissed, with instructions to
keep up the massage of the gums an antiseptic care of the mouth. One to three treatments
were required in the cases treated.
Fig. 66 - D'Arsonval Outfit for Diathermy.
Dr RF. Morel (Bulletin du Syndicat des Chirurgiens-Dentistes de
France, Sept.-Oct., 1910, Jan.-Feb., 1911) makes use of medicaments in connection with the
high frequency. He claims that the high frequency effleuve renders mucous membranes porous
and facilitates the penetration of medicaments, and that the simultaneous application of
the solution and the current produces an electro-chemic effect. He decomposes by the
currents a solution of potassium bi-chromate, claiming that the base will be taken up by
the diseased tissues.
After thoroughly removing the tartar from the teeth, he carefully
irrigates with peroxide and evacuates all of the pus. Then he paints the teeth and gums
with the following solution, using a spatula to get it up as far as possible around the
R - Fluoride of Ammonia.........1 gramme
Chloride of Ammonia.........1 gramme
Chloride of Potash.............1.5 gramme
Salicylate of Theobromine. 1 gramme
Distilled Water...................20 grammes
M. - Filter.
This solution favors ionization and lessens the resistance of the
tissues to porosity.
A pad is then soaked in a ten per cent aqueous solution of
bichromate of potash and held over four teeth and a vacuum electrode held over this for
about fifteen minutes, with close contact. He only treats four teeth at a time. In
advanced cases he uses a metal point and carries a few sparks up into the infected canals.
The vacuum tube application is for cataphoric purposes, and one of
the electrodes illustrated herewith having a cup to hold the saturated cotton may be used
for this purpose.
He repeats this treatment every second day, sometimes giving three
five-minute seances with eight minutes' rest between. Usually four treatments produce a
cure, occasionally six, seven or eight have been required. During the whole course of
treatment the patient washes the mouth six times a day with the following solution, using
half a glass each time:
Sodium salicylate.............10 grammes
Sodium fluorosilicate........2 grammes
Distilled water..................1 Litre
Dr. Irwin Jirka applies methyl salicylate in these
cases, driving it in with the vacuum electrode. He treats for eight minutes every other
day. Reports a number of cases cured in three to fifteen treatments. Hubbel uses the
cataphoresis electrode first and then the ball pointed pyorrhea electrode to massage the
gums for five or six minutes each, treating daily until improvement takes place.
Dessication, Metallic Ionization and Phoresis. I
have been furnished with a translation of a paper by Dr. A. A. Nouel of Venezuela. This
paper, read at the Dental Section of the Medical Congress at Caracas in 1911, is entitled,
"Dessication, Metallic Ionization, and Phoresis of the Canals in One Sitting with
High Frequency Currents." The author's methods seem to be distinctly original. He
speaks of using at first a coil and resonator and with this and iodide of potash because
this chemical absorbed the ozone when the current was introduced into infected root
canals. After four years of experimenting he found a method and a machine that enabled him
to get simultaneously metallic ionization and thermopenetration.
He says: "I have used the *** high frequency coil
but even though the machine is just as efficient as other more powerful coils for
fulguration; with vacuum electrodes and with the ozone inhaler, in the dessication of the
canals, the current is found to be of too pronounced faradic character.
"I have also used several other types of high
frequency machines, and found the one most suitable giving a smooth, high frequency
current without any faradic sensation, such as is used in diathermy. In this case there
will be felt by the patient nothing but a progressive increase of warmth, if there is no
continuity of solution. If there is one, no matter how small, beside the progressive
thermic increase, there will result an ionization of the canal in which a small arc will
be established. This arc is formed between the walls of the canal and extends the full
length of the electrode.
Fig. 68 - Dental Electrodes.
"The electrode is connected by means of a flexible
and well-insulated metallic conductor to the right hand 'auto-condensation' terminal. The
electrode handle may be about ten centimeters long, and made of either fine wood or ivory,
with a metallic point similar to that of the broach holders employed in dentistry. Small
pieces of either copper or zinc wire, as required in each case, will be fitted to the
handle. In some cases, where no abscess is formed, I believe the copper is superior to the
zinc electrode. To substantiate this statement, I have observed that after a diseased spot
has been treated with a copper electrode no pain is felt if that spot is touched.
"Before the current is turned on, it is better to
thoroughly dry the cavity leading to the canal in order that the sparks may not be
diverted, but will confine themselves to the length of the wire and walls of the canal
throughout its length.
"I firmly believe that the metal, during its
ionization, is cataphorically introduced into the dental canals through the apex, and that
once in the presence of the salts that form the composition of the blood, a chloride is
formed, this being the reason why the peridontium and adjacent parts are irritated when
zinc is employed. A zinc electrode is beneficial in case of an abscess on account of the
chemical composition formed by the zinc.
"The ionized and ozonized copper is also
introduced into the dental canals by means of the cataphoric action of the current, thus
forming a deposit of oxide or bi-oxide of copper, which will permanently act as a
disinfectant. I shall later on explain the method through which its action is brought
"Although a tooth may be profoundly infected (it
is understood that I refer to a tooth without pulp), with inflammation of the peridontium,
with an abscess or fistula, it can be 'stopped' in one sitting, fearing no ulterior
difficulties, if this novel method is employed.
"The technique is very simple; After the pulp
chamber is open it is to be moistened with a small quantity of trikresol and iodoform or
trikresol and formalin, after which the electrode is applied, being held at a distance of
half to one millimeter and moving it over the surface until the cavity is dry. A broach is
now employed, being operated into one-half the length of the canal, drying with cotton and
compressed air, not too warm; then the copper wire is introduced and the current turned on
for five minutes. The broach is now used again, this time reaching to the apex. The canal
now being perfectly freed from the bits of pulp and other foreign bodies, is now
thoroughly dried with cotton inserts. The copper electrode treatment is then repeated for
five minutes, and after this time has elapsed the tooth may be 'stopped.'
"The great efficacy of this modality is supported
by the fact that the dental canals constantly maintain a certain humidity, which serves as
an easy conductor for the introduction of the ionized metal, and permits the easy access
of the flowing-in process of the ozone while being dried by the thermopenetration, which
goes to complete the oxidation and the consequent coating of copper, leaving it
permanently deposited in a state of oxide or bi-oxide of copper."
Abscesses. The dental technique advised by some
operators consists in ten or fifteen minute applications of a mild current in contact with
the cheek, followed by the use of one of the cataphoresis electrodes containing cotton
saturated with iodine and aconite solution. Duration of this application about eight or
ten minutes. Jirka uses methyl salicylate, and also speaks of formo-cresol, which I infer
is used with the cataphoresis electrode.
Drs. Barber and Van Valkenburg have reported a case
where the copper wire was employed in treating an abscess.
Post-operative Pains. For the pains and soreness
existing after extraction or after setting bridges or crown, the use of the cataphoric
electrode with any suitable solution has been recommended, followed by application of mild
current with the ball-pointed pyorrhea electrode.
Sterilizing Root Canals. Another method of
sterilizing root canals is the touching of the pointed dental electrode (carrying current
enough for a half-inch spark), to a broach which has previously been inserted in the
canal. The broach carries the current into the canal. The direct D'Arsonval current may be
used the same way.
Fig. 69 - Portable Outfit for Dentists.
Bleaching the Teeth. Hubbel says: "Place
your bleaching solution on a fibre of asbestos or cotton, placing it in the cavity of the
tooth and applying the point of the electrode directly against this fibre, the cataphoric
action of the current driving the solution into the dentine, getting results much quicker
than from ordinary measures. Care must be taken that the apex of the tooth is first
stopped with gutta-percha so that there is no danger of the solution being forced through
the apical foramen."
Diagnosing Live from Dead Pulp. The pointed
dental electrode is used with a mild current, and the point applied to the cusp of the
tooth. If the pulp is alive the patient will feel the current; if he does not, the tooth
Obtunding Sensitive Dentine and Devitalizing Teeth.
"In obtunding sensitive dentine, a small crystal of carbolic acid is placed in the
cavity and the pointed electrode is used in the generator, the current being toned down as
mildly as possible. The point of this electrode is then placed against the cavity, and if
still sensitive, use the current for a half minute longer. You may now start to excavate,
and if the one application of the carbolic acid does not last sufficiently long to
complete the operation, place another tiny crystal in the cavity and apply as before. In
the majority of cases, operations have been rendered entirely painless by this method of
"In devitalizing the teeth a small crystal of
novocain is placed in the cavity, or, if no cavity is apparent, cut into the enamel with a
very small stone, placing a crystal of novocain therein and dipping the tip of the
electrode in adrenalin. Apply the high frequency current to this with a very mild flow of
current the same as in obtaining sensitive dentine, using the current for about one
minute. Drill into the teeth until as close to the pulp cavity as possible without
unnecessary pain, and again apply a crystal of novocain and use the current for about a
minute to a minute and a half, and in most cases it is then possible to cut into the pulp
cavity. If the nerve is then sensitive, pressure anesthesia is advisable. The greatest
trouble that we find in getting success from this treatment is the inability of the
operator to successfully control his current, as it takes considerable practice in order
to get the proper amount of stimulation. But, after some experimenting, it is possible to
get results in the majority of cases." - Hubbel.