Eberhart's Manual of High Frequency
Noble M. Eberhart
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 fig. 68.
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 roots:
R - Fluoride of Ammonia.........1 gramme
Chloride of Ammonia.........1
Chloride of Potash.............1.5
Salicylate of Theobromine.
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.
Fig. 68 - Dental Electrodes.
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
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
"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.
"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.
Fig. 69 - Portable Outfit for Dentists.
"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 about.
"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
"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
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.
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
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 is devitalized.
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 treatment.
"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.