CA2002627A1 - Device for dental electroanalgesia - Google Patents

Abstract

DEVICE FOR DENTAL ELECTROANALGESIA
Abstract of the Disclosure The device for dental electroanalgesia com-prises series-connected a low-frequency electric pulse generator with an electric pulse repetition frequency setter, an electric pulse front discrimi-nator, an electric pulse shaper, a current ampler, a transformer, and an electric pulse amplitude regu-lator electrically connected to electrodes. The elect-rodes are placed on a corresponding reflexogenic zone of the auricular concha and on the mucosa of the al-veolar process of one of the jaws within the area of the projection of the root apices of the patient's teeth being prepared. The device comprises also a temperature sensor placed on the patient's face skin in the area of segmental innervation of the patient's dental tissues being prepared. Connected to the tem-perature sensor output is the input of an electric pulse duration regulator whose output is connected to the input of the electric pulse shaper.

Description

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Z0026~7 ., :
~ `, Technical Field .:
~ he present invention relates generally to ele-ctrotherapy and more speci~ically to devices ~or den-5 tal electroanalgesia. ~- -Background of the Invention ~ he present invention will flnd application ror anesthesiological support of an opsrative interferenGe involved in a stomatological manipulation, i~e., pre-10 paration o~ har~ dental tissues ~or a ~i~ed partial ~;
denture, a~ well as in tooth ~illing and in operative treatment Or carie~
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An analgesic effect o~ a pulsed electric curreut --i9 based on activatio~ o~ the antinociceptive orga-nism's system, which causes a complete or partial blocking o~ nociceptive impulses' conduction. A dis-tinguishiQg ~eature o~ such an analgesic technique resides not ouly in a reduced patient~s appreciation pain but also amelioration or hi~her p~yc~oe~o~
tional state and normalization Or somatovegetative reaction~ o~ the patient'9 organi~m.
One state-of-the-art device ~or electrostimula- ~-tion o~ patient's ti~sue~ is known to be e~tensively ~1 used curre~tly (SU, A, 1,0~4,650~, said device com~
25 prising a low-frequency current pulse generator, a ~-high-irequency current pulse generator, the outputs o~ both bein~ conclected to the inputs o~ an electric `" ~

20~\Z627 pulse front discriminator, whic~ is in fact a shift -register. The device comprises also a pulse shaper based on series-connected a ~irst ~lip-flop and an A~D gate.
The output o~ the low-frequency generator is also connected to the input o~ the first flip-~lop.
~he output Q~ the A~D gate is connected to the input of a current amplifier, while the output of the current amplifier is connected to the primary winding of a transformer, and the secondary winding of the transformer is connected, via the shift regist-er, to electrodes. The input of a second pulse shaper is connected to a resistor, while the output of the pulse shaper i~ connected to a first input of a se-¦ 15 cond flip-~lop. The other input o~ the second ~lip-¦ flop is connected to the output of the high-~requency curre~t pulse ge~erator, while the output of the se-cond rlip-flop is connected to the other input of the AND gate. The high-~requency pulse generator produc-es a train of electric stimuli tpulses) o~ a prede-termined adjustable duration and repetition ~requency~
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The output voltage of the second rlip-flop gates the pulses at the input of the AND gate so that those -~
pulses are passed at the output of the AND gate whose duration is not in excess o~ a value preset ~ the low-frequency generator. The electric stimuli arrived ~

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from the output of the AND gate, are applied to the current amplifier, which is loaded with the trans~
former. The amplitude of electric pulses delivered Il by the transrormer secondar~ is increased with an 5 increase in the duration of the voltage puLses applied to the transformer primar~, whereas the electric puls-es rrOm the trans~ormer secondary are delivered to the electrodes. To provide an analgesic erLect in pre- ;~
paration of hard dental tissues the active electrodes 10 o~ the device are applied to the skin o~ re~lexOgenic `~
zones, such as, e.g., the auricular concha, while the passive electrodes of the device are applied to the patient's ~ace skin clo~e to the area o~ an intend-i ed stomatological inter~erence. In a given device a 1 15 derinite pulse repetition ~requency and duration are j set by manual adjustment of a variable resistor, while the intensity of tissue electrostimulation at the ;~
place o~ application o~ the active electrodes is pre~
set according to patient's subjective sense o~ intense vibration under the electrodes due to electric cur-rent ~lowing therealong. As a result o~ the electro~
stimulation process the patient~s pain sensitivity threshold is increased and tne intensity Or v~bra- ;
tion se~se is reduced or aisappears altogether. To provide an analgesic ef~e,ct adequate to the patient's painful sensations during an ope~ative interrerence ; .

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t~e dentist increases the amplitude o~ the current pulses by manual adjustment of the variable resistor s in order to increase the intensity of electrostimula-s tion and to attain the original sensory acuity o~
electrostimulation. ~o provideanan~gesic e~ect adequate to the intensity of ~he patient's pain~ul sensations, it is necessary to correct the intensity or electrostimulation ~ive or six times ~or 25 to 30 minutes by manual adjustment o~ the varia~le resistor.
~i~ Thus, the intensity of anesthesiologic electro-stimulation depends on patient~s subjectivesensation, which is inrluenced by his/her psychoemotional state, and on practical skill and experience of the dentist involved.
Manual adjustment in the course of electrostimu-Iation results in a prolonged period o~ time required rOr attaining an analgcsic e~rect a~fects adversely the adequacy o~ electroanalgesic eY~ect to patient'a pain~ul sensations during surgery. Tne parameters o~
e~fec~ive electric pul~es, i.e., amplitude, repetition ~3 ~requency and duratiocl are not concerne~ with an in-` dividual dynamics o~ increasing the patient's pain : sensitivity threshold. The device Yails ~o provide prognostication o~ an analgesic ef~ect o~ electro-stimulation. Inadequacy o~ the analgesic e~ect to patient's pain~ul sensations during surgery can be ;' ~ 5 -.,. ,,,~, "
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determined only in the course o~ a stomatologic inter~
~erence according to patient's painrul sensation.:~ .
Summary o~ the Invention It is an object of the invention to provide an 5 analgesic efrect produced by electric pulses ade~uate-:~ :
to patient's painful sensations during an operativs i nterf ere nc e .
Said object is accomplished due to the ~act that ~.
in a device ~or dental electroanalgesia, comprising 10 series-connectea a low-frequency electrlc pulse ge- ~ ;
nerator with an electric pulse repetition fre~uency setter, an electric pulse iront discriminator, an elec-trio pulse shaper, a ourrent amplifier, a trans~ormer, and an electric pulse amplitude reg~ulator electric-~-ally connect~d to at least two electrodes, according to the invention, the output of the electric pulse re- ~ ;
; petition ~requenc~ setter is ¢onnected to a ~irst ad~
justment input of the low-~requency electric pulse generator and there are additionally incorporated a;
20 temperature sen~or placed o~ the patient's Yace skin:; :
in the area o~ segmental innervation o~ the patient's ;
dental tissues being prepared, and an electric pulse .
duration regulator whose input is connected to the~:
output o~ the temperature sensor and its output is~:
connected to the input o~ the electric pulse shaper, while the electrodes are placed on a corresponding re~

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flexogenic zone of the auricular concha and on the mucosa o~ the alveolar process o~ OQe of the iaWs within the area of the projection o~ the root apices o~ the patient's teeth being prepared.
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It is expedient that, with a view to increa~ing the e~Yiciency o~ dental electroanalgesia in res-ponse to a change in patient's pain sensitivity thre-shold, the device should comprise additionally an electric pulse repetition ~requenc~ regulator whose input i9 connectea to the output o~ the te~perature sensor, while its output is connected to a second ad-justment input o~ the low-rrequency electric-pulse generator.
Practical application o~ the present invention makes it possible to automatically adjust the Para~
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meters o~ the pulses generated, that is, repetition ~re-quency and duration depending on patient's skin tempe-,, rature as measured by the temperature sensor and is ;-. ... ~
in errect an objective evidence o~ a reduced patient's ~
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- 20 pain~ul sensation and a measure of a prolonged clinic-al errect o~ electroanalgesia applied to patient's tissues being operated upon. In the process o~ anal- ~ -; gesia application the puise duration is increased, -while the pulse repetition rrequency is reduce~,thus -;
retaining t~e patient'3 orig~nal sensation of tissue vibration under the electrodes when electric cur-;,. .: ~, '' ,'' '`'-. ~

~` 200~ 7 ~:' rent flows therealong. ~his enables one to carry out dental electroanalgesia adequate to the intensity o~
patient' 5 painful sensations during an operative in-terference.
Brie~ Description o~ the Drawings In what rollows the present invention is illust-rated by a detailed description o~ a device ror den-tal electroanalgesia and s~me specific exemplary em-bodiments thereof with rererence to the accompanying , 10 drawings, wherein:
,, FIG. 1 presents a ~unctional electric bloc~ dia-l~ gram o~ a ~irst embodiment o~ the device, according I to the invention;
P~IG. 2 is an elementary electric diagram o~ a rirst em~odiment o~ the device, according to tne in-i vention;
¦ FIG. 3 shows a functional electric block diagram ¦ o~ a second embodiment o~ the device, according to the invention; and ~IG. 4 is an elementary electric diagram o~ a second embodiment o~ the device, according to ~he in- :~
, vention.
De~ailed Description o~ t~e Invention Tne device ror dental electroanalgesia compris-25 es series-connected a low-~requency electric puLse ge- ~ :
nerator 1 (~IG. 1) with an electric pulse rep~tition - 8 - ~ :

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~requency setter 2, an electric pulse front discrimi-s nator ~ made as a difrerentiating circuit, an elect-. ric puLse shaper 4, a current amplifier 5 and a step-up trans~ormer 6, an electric pulse amplitude regulat-5 or 7, a current meter 8 connected to an active elect-rode 9 and a passive electrode 10. The active elect-rode 9 i9 placed on a refle~ogenic zone o~ the pati-ent's auricular concha innervated with a respective branch of tne prigeminal nerve. The passive electrode 10 is placed on the mucosa of the vestibular surface of the alveolar process o~ one o~ the ~aws within the area o~ the projection o~ the root apicei o~ the ~-pa~
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tient's teeth being prepared. The device comprises also a temperature sensor 11 made as a thermoresist~
15 or placed on the skin o~ patient's ~ace-in the area o~ segmental innervation o~ patient's dental tissues being prepared. The output of the temperature sensor 11 is connected to the input o~ an electric pulse du-ration regulator 12 made as a transistor-based ampli- ~ -~
20 ~ier. An alternative embodiment is possible, wherein ;
the electric pulse duration regulator 12 is made a9 an electric element with variable parameters,` e.g., - ~
a variable capacitor. ~ --The output o~ the electric pulse duration re- --~
gulator 12 is connected to the input of tAe electric pulse shaper 4. The input o~ the temperature sensor ~-_ g ~
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~ ll and the input of the electric pulse duration regu-.~.~ . .
; lator 12 are connected to the output of a voltage re- -`; gulator 13.
In a specilic embodiment of the device the low-~re~uency electric pulse ~enerator l (FIG. 2) is made aQ a first inverter 14 connected in parallel to the electric pulse repetition frequency setter 2 made as a varia~le resistor. Tne output of the inverter 14 is connected to the input o~ a second inverter 15. A
capacitor 16 is connected to tne out~ut of ~he invert-er 15 and to the input of the inverter 14. ~he elect-ric pulse ~ront discriminator 3 i9 made as a ~i~feren-tiating circuit, i.e,, a capacitor in this particular case. Tne electric pulse shaper 4 is made as a one-.; 15 shot multivibrator incorporating an AND gate 17, whose ~irst input is connected to the output o~ the electric pulse front discriminator 3, while its output is con-nected, via a capacitor 18, to the input o~ an inver~- ;
er 19. ~he output of the inverter l9 is connected to a second input of the AND gate 17. ~he current ampli-fier 5 is built around a composite transistor and com-prises a ~irst transistor 20 whose base is connected, via a resistor 21, to the output of the inverter 19 . .
and its emitter is connected, via a resistor 22, to ,2 25 the base of a second transistor 23. ~he collector of `. the rirst transistor 20 is connected to the collector ~ . .

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` 2002627 i of the second transistor 23. The emitter of the se-cond transistor 23 is connected to a voltage source ~omitted in the Drawing). A primary winding 24 o~ the tep-up trans~ormer i3 connected to the collector o~
the second transistor 23. A secondary windi~g ~5 o~
the step-up transformer 6 is connected to the termin-als of the electric pulse amplitude regulator 7 made as ~1-a potentiometer. The current meter 8 is connected ac- -`
ross a diagonally opposite pair o~ terminals o~ a lU brid~e circuit 26 ~uilt around semiconductor diodes ~ :~
27. ~he bridge circuit 26 is connecte~ with one o~ its .-~
outputs to the control input o~ the electric pulse ¦ -amplitude regulator 7 and with the other output, to -the electrodes 9, 10. ;.
~5 ~he electric pulse duration regulator 12 is made as a transistor 28 whose collector is connected to the ~;
input o~ the inverter 19 of the electric pulse shaper 4, while the emitter is connected to a resistor 29, - `~
and the base is connected to tne temperature sensor -, 20 11. ~ne voltage stabiiizer 13 comprises a Zener diode :~
- 30 connected, via a resistor 31, to a voltage source ;~
omitted in the DrawingJ, and via a resistor 32, to tne temperature sensor 11.
Tns device comprises also a common bus 33, which is connected to the negative pole o~ an electric pow-er source (omitted in the ~rawing~. Connected to the :~

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common bus 33 are the passive electrode 10, tne anode o~ the ~ener diode 3~, one o~ the ou~puts o~ the tem- -i~ perature sensor 11, the lead of the resistor 29, the leads o~ the pri~ary wi~ding 24 and ~he secondary ~ 5 winding ~5 o~ the transformer 6, and o~e o~ the out~
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puts of the electric pulse amplitude regulator 7.
~ith a view to adjusting the pulse repetition frequency the device comprises additionally an elect-ric pulse repetition frequency regulator 34 (FIG.
10 which consists of a transistor 35 (~IG. 4) whose ~ collector is connected to the input o~ the inverter 14 : :;
¦ o~ the low-~requency electric pulse generator 1, while ¦ the emitter is connected to a resistor 36. ~ha base o~ the transistor 35 is connected, via a resistor 15 37, to the resistor 32 o~ the electric pulse duration ~ ~.
regulator 12, as well as to the cathode of a diode 38 whose anode is connected to the temperature sensor 11.
In addition, the electric pulse duration regu-~:- lator 12 comprises also a diode ~9 wr~ose cathode is : 20 connected to the base o~ the transistor ~8 and its - anode is connected to the te~erature sensor Ll.
he device ~or dental electroanaigesia, accord-I ing to the invention, operates as follows.
The active electroae 9 (~IG. 1) is applied to 25 a corresponding re~le~o~enic zone of the auricular ;-~
concha, while the passive electrode 10 is placed - 12 - .

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j on the mucosa of the vestibular sur~ace of the alveolar process of the upper or lower jaw in the area of the - -projection of the root apices o~ the patient's teeth being prepared. The temperature sen~or 11 is placed ~ -5 on the skin o~ the patient's race in the area of seg~
mental innervation of the patient's tissues being :;
prepared, for instance, at the place o~ the pro~ection ~`
of the infraorbital or mental roramen. ~hen the re-petition rrequency of the pulses produced Dy the low- ~`~
10 Irequency generator is adjusted within 14 and 16 Hz with the aid of the electric pulse repetition frequ~
ency setter 2, whereupon the pulse amplitude is set .:~
against the patient's subjective sensation o~ a mode- -~-rately intense vibration under the electrodes 9, 10, `~:.
15 using the electric pulse amplitude regulator 7. :-A change in the resistance value of the resistor . `-of the electric pulse repetition frequency setter 2 results in a change of the discharge time constant ..
Or the capacitor 1~ (FIG~ ~) of the low-frequency `~
20 electric pulse generator 1, whereDy the repetition ` `, ~requency of the pulses produced ~y the generator 1 is altered. ~ext the one-shot multivi~rator o~ the .
pulse shaper 4 is triggerea against the leading edge an output electrio pulse delivered from the out-25 put o~ the generator 1 through the electric pulse ,~
~ront discriminator 3 to the input o~ the electric 13 .
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pulse shaper 4. As a result, electric puLses are de-livered ~rom the output of the pulse shaper 4, the du-ration of which pulses depends on the resistance va-lue o~ the electric pulse duration regulator 12.
5 The resistance value o~ the regulator 12 depends in turn on the temperature o~ the patient~s race skin as measured by the temperature sensor 11. With a cer-tain approximation the resistance value of the tempe-rature sensor 11 is in linear relationship With the 10 temperature of the patient~s race skin, ~here~ore the duration of electric pulses passing through the pati-ent's race skin located between the active electrode 9 and the passive electrode 10 is also in linear re-lationship with the skin temperature.
¦ 15 The voltage regulator 13 provides for stable ~-¦ regula.tion of electric pulses ror duration and repe-tition rrequency in response to a change in the volt-~ age of a power source (omitted in the Drawingj.
¦~- The one-shot multivibrator of the pulse shaper ¦~20 4 is triggered by the positive electric pulses deliv-- ered ~rom the output of the electric pulse rront dis-criminator 3. As a result, the AND gate L7 is en~
abled, and the capacitor 18 o~ the pulse shaper 4 dis-charges. The inverter 19 of the pulse shaper 4 is 25 disabled during discharge o~ the capacitor 18. The resistance value of -the température sensor 11 de- -~,j l ~"
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creases depending on an increase in the temperature o~ the patient's face skin, whereby the transistor 28 o~ the regulator 12 i9 disabled, its internal resist~
ance increases and duration of the- output electric 5 ~ulses of the shaper 4 is increased, too. All the time `~
while the one-shot multivibrator o~ the pulse shaper 4 iS enabled the inverter 19 is disable~, which en-ables the composite transistor o~ the current ampli~ier 5 based on the transistors 20 and 23. With the tran- ;
sistor ~3 enabled electric current is ~ree to ~low through the primary winding ~4 o~ the transiormer 6 ~;~
and the common bus 33 o~ the device. ~-Volta~e pulses are induced in the secondary;``
winding ~5 o~ the transformer 6, the value o~ said--~
pulses being adjusted with the aid of the electric pulse amplitude regulator 7.
The mean value o~ the output electric pulses is measured by means o~ the current meter 8 connected between diagonally opposite pairs o~ terminals o~ the bridge circuit 26. ~lectric pulses are applied to the active electrode 9 through the bridge circuit 26 -and the current meter 8. Thus, electric current ~lows ~;
along a circuit incorporating the active electrode-~
9, the patient's tissues, t~e passive electrode 10, $ 25 the common bus 33 o~ the device. ~-An automatic increase in ~he load c ~rent, the , ... ....
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oad ~eing in ~act the patient's race skin located between the active electrode 9 and the passive elect-rode 10, in the course of dental electroanalgesia procedure, makes it possible to ma~ntain efricient 5 electrostimulation of the re~lexogenic zone o~ the auricular concha in response to increased threshold t value of pain appreciation. However, an increase in 9 the mean value o~ electrostimulation current might in-rlict painrul sensations upon tne rerlexogenic zone o~

10 tne patient's concha or its "~reakdown~' and insurri-cient~y opiate-~ediated analgesic e~ect on the pati-j ent~s organism. ~n automatic adjustment o~ the mean value o~ electric pulses in the course of dental elect- ``
roanalgesia is carried out by the elec~ric pulse.; re-15 petition frequency regulator ~4 (~IG. 3).
~ The electric pulse-repetition ~requency regulat- .
¦ or 34 is controlled by the ~emperature sensor 11. As `~
~ soon as the temperature o~ the pabient's face skin ¦ rises at the place of application o~ the temperature 1 20 sensor 11 its resistance value drops, the transistor 1 35 (FIG. 4) o~ the regulator 34 is disabled and its internal resistance increases, which in turn reduces the repetition ~requency o~ electric pulses due to a higher resistànce o~ the discharge circuit in the ~5 capacitor 16 of the generator 1. .
The diodes 38, 39 perrorm electric isolation of - 16 - - ...

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~ zoozl6Z7 the output Of the temperature sensor 11 and the elect-ric pulse duration regulator 12 from the electric pulse repetition ~requency regulator 34.
~ne value of the electric pulse repetition fre-quency is substantially in linear relationship (with some approximation~ to the pa~ient's race skin. Thus, -~`
simultaneous increase in the duration of electric sti~
muli (pulses) and reduction or the electric pulse re-petition ~requency make it possible to maintain a sta~
ble mean value o~ electric stimuli applied, which in turn enables one to attain higher opiate-mediated anal~esic e~rect on the patient's organism.
The proposed device have been trialled in thera-peutic and orthopedic dentistry clinics. Application of the device makes it possi~le to carry out painless preparation of hard dental tissues in ~8 percent o~
- cases in operative treatment o~ caries and in 95 per- -~
cent of cases in teeth preparation for rixed partial dentures.
Given below is an example o~ practical a~plica-tion o~ the device ~or dental electroanalgesia, ac- ;~
cording to the invention.
Patient~s diagnosis is one o~ the de~ectso~
the maxillary teeth of t~e third class after Eennedy. '~
25 Teeth preparation for artificial crowns is indicated. ~
The active electrode is smeared with an elect- -- ,.~.. .
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~- 200;~627 rode paste and placed in the area o~ the re~le~ogenic zone o~ the auricular concha, that is, in the middle o~ the auricular lobule under the tragus and is fixed in position by a holder. The passive electrode is 5 placed on the mucosa o~ tne vestibular sur~ace of the alveolar process of the upper jaw in the area oY the projection of the root apices o~ the teeth being pre-pared.
The temperature sensor is placed on the patient's 10 face skin at the place of the projection of ~he right infraorbital ~oramen and is secured in position with a piece o~ plaster. Next the device is turne~ in and an electric pulse repetition frequency o~ 15 Hz is adjusted by means of the ~requency setter 2, and an ~-electric pulse amplitude of 1.0 mA is set by the re-gulator ~7 against tne patient's subaective sensation o~ intense vioration in the area of the re~le~ogenic zone. For the following 15 minutes the skin tempera-ture in the area o~ the right infraorbital ~oramen rises ~rom 33.5 to 37.0C.In the course o~ the dent-al electroanalgesia procedure the electric pulse re-petition ~requency reduces to 2 Hz, whereas the dura-tion of electric pulses increases rrOm 101 ~9 to 400 ~s. The mean value of electric pulse amplitude remains nearly stable, ran~ing within 1.7 to 6.6 mA.
Electrostimulation was contlnued throug~hout the whole - 18 - , 200Z627 ~ ~-period o~ teeth preparation. In the course o~ the teeth preparation there is noticed stable indices of peripheral hemodynamics; no painful sensations are felt by the patient.
Clinical application o~ the device makes it pos- `;
sible to cut down the treatment costs per patient ~.5 to 3.0 times and to increase the ~cope of stomatolo~
gical service 15 to 16 times. Use of the device en~
ables one to prognosticate the clinical ef~ect of ele-ctrostimulation analgesia, to increase the adequacy o~ anesthesiologic stimulation 3 or 4 times, to en-hance electroanalgesia er~icacy and to redu¢e by 20 to 40 percent the time within which an analgesiG ef-fect is attained.
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Claims (2)

1. A device for dental electroanalgesia, com-prising:
- at least two electrodes; a first electrode placed on a corresponding reflexogenic zone of the auricular concha; a second electrode placed on the mucosa of the alveolar process of one of the jaws within the area of the projection of the root apices of the patient's teeth being prepared;
- a low-frequency electric pulse generator hav-ing a first adjustment input and an output;
- an electric pulse repetition frequency sett-er having an output connected to the first adjustment input of said low-frequency electric pulse generator;
- an electric pulse front discriminator having an input and an output and connected with its input to the output of said low-frequency electric pulse generator;
- an electric pulse shaper having a first input, a second input, and an output and connected with its first input to the output of said electric pulse front discriminator;
- a current amplifier having an input and an output and connected with its input to the output of said electric pulse shaper;

- a transformer having an input and an output and connected with its input to the output of said current amplifier;
- an electric pulse amplitude regulator having an input and an output and connected with its input to the output of said transformer, while its output is electrically connected to said electrodes;
- a temperature sensor having an output and plac-ed on the patient's face skin in the area of segmental innervation of the patient's dental tissues being prepared;
- an electric pulse duration regulator having an input and an output and connected with its input to the output of said temperature sensor and with its output to a second input or said electric pulse shaper.

2. A device for dental electroanalgesia, com-prising:
- said low-frequency electric pulse generator having a second adjustment input;
- an electric pulse repetition frequency regulat-or having an input and an output and connected with its input to the output of said temperature sensor and with output, to a second adjustment input of said low-frequency electric pulse generator.