Anesthesia electrode and applicator assembly

TENS electrodes and connectors useful with such electrodes are disclosed. The electrodes include active electrodes and return electrodes having a common carrier with a field of pressure sensitive adhesive for adhering the electrode to a hand (finger or thumb) of the practitioner or an applicator. Extraoral electrodes adhere to facial skin of mammals and provide TENS treatment for intraoral-procedures. The electrodes can be single channel or dual channel to combine active electrodes and return electrodes on one electrode. The connector can be single channel or dual channel and has a ridge for projecting through the tab portion of the electrode for more secure mechanical and electrical connection. Optionally, a dual channel electrode is used in combination with an elongated applicator having a bifurcated end in order to facilitate guiding a syringe needle toward a desired injection site.

FIELD OF THE INVENTION 
This invention relates to electrodes and applicators used for anesthesia. 
BACKGROUND OF THE INVENTION 
The treatment of intraoral conditions typically involves pain or 
discomfort. Since the earliest days of anesthesia, attempts have been made 
to minimize pain or discomfort during medical and dental procedures, 
including intraoral-procedures. 
For purposes of this invention, "intraoral-procedures" means health care 
manipulations by a health care practitioner done inside the oral cavity of 
a mammalian patient. Nonlimiting examples of intraoral-procedures include 
periodontal procedures, dental procedures, oral surgery, and orthodontia. 
Typically, injections of local anesthetics are employed intraorally for 
temporary anesthesia. But these invasive procedures produce discomfort and 
cause high anxiety levels in patients. There is also a delay inherent 
between the injection and the onset of anesthesia. 
Transcutaneous electrical nerve stimulation (TENS) has been employed as a 
method to reduce pain or discomfort for mammalian patients. Typically, the 
application of a low voltage, low current electrical signal through the 
skin counteracts nerve stimulation indicating pain or discomfort. 
TENS biomedical electrodes are well known but have not previously been 
widely applied to intraoral-procedures. None of the TENS biomedical 
electrodes for intraoral-procedures were convenient to use because these 
electrodes were intended to stick to the soft intraoral tissue during the 
intraoral procedure, particularly while a cavity was being prepared and 
filled with restorative material. These electrodes frequently did not 
maintain adhesion to soft, moist tissue during these procedures in the 
crowded, irrigated, saliva-filled mouth. Further, saliva or irrigating 
fluids can drain current away from the tooth needing pain control. Another 
difficulty with these electrodes was the use of a splayed wire as the 
electrical conductor contacting the conductive adhesive in the electrode. 
This splayed wire could cause unacceptably high current densities. 
U.S. Pat. No. 4,782,837 (Hogan) discloses a dental analgesia method and 
apparatus where one TENS electrode is applied to the hand and another TENS 
electrode is applied to the face. 
TENS biomedical electrodes have employed a delivery path for electrical 
signals that emphasizes the surface area of the field of conductive 
adhesive being greater than the surface of the electrical conductor 
delivering the electrical signals to the field of conductive adhesive. 
U.S. Pat. Nos. 4,694,835 and 4,458,696 disclose TENS electrodes where 
perimeter dimensions of pad portions of electrical conductors are within 
perimeter dimensions of contiguous fields of conductive adhesives. 
Thus, the present intraoral medical practices have not found a solution to 
a comfortable and quick administration of anesthesia. 
SUMMARY OF THE INVENTION 
The present invention solves the need for a comfortable and quick 
administration of anesthesia. 
The present invention provides a transcutaneous electrical nerve 
stimulation assembly that comprises an elongated applicator having a shaft 
and a head connected to the shaft. The assembly also includes an electrode 
having an electrically conductive pad portion releasably connected to the 
head of the applicator. A lead is electrically coupled to the pad portion, 
and a means is provided to releasably connect the lead to the shaft such 
that the lead extends along at least a portion of the length of the shaft. 
The present invention also provides a transcutaneous electrical nerve 
stimulation assembly that comprises an elongated applicator having a shaft 
and a head connected to the shaft, and the head includes a bifurcated end. 
The bifurcated end presents a first end section, a second end section and 
a channel located between the first end section and the second end 
section. The assembly also includes an electrode releasably connected to 
the head. The electrode includes a first pad portion extending over the 
first end section, a second pad portion extending over the second end 
section and a notch located between the first pad portion and the second 
pad portion. The notch is aligned with the channel. 
Another aspect of the invention relates to a transcutaneous electrical 
nerve stimulation applicator that comprises an elongated shaft, and an 
elongated neck connected to the shaft and extending at an angle relative 
to the longitudinal axis of the shaft. The applicator also includes a head 
that is connected to the shaft, and the head includes a bifurcated end. 
An advantage of the present invention is that the lead is retained against 
the shaft of the applicator by the adhesive, and normally does not 
interfere with other concurrent intraoral procedures. The lead also does 
not normally obstruct the practitioner's view of the oral cavity, thereby 
providing a convenience to the user. Additionally, the channel of the 
bifurcated end of the applicator, being aligned with the notch between pad 
portions of the electrode, provides a guide for assisting the practitioner 
in guiding the needle during an injection. The channel and the notch 
increase the accuracy of placement of the injection and enable the 
practitioner to avoid using his or her fingers to guide the needle, so 
that inadvertent puncture or other injury of the practitioner's hand from 
the needle can be avoided. 
A feature of the present invention is that perimeter dimensions of the 
electrically conductive surface are at least equal to and preferably 
greater than the perimeter dimensions of the field of conductive adhesive 
receiving the TENS electrical signals from the electrical conductor. 
Another feature of the present invention is the maintenance of relative 
uniform current densities during TENS oral administration without 
significant areas of high and low current density. 
The present invention also solves an unexpected problem associated with the 
dimensions of the perimeter of a field of conductive adhesive relative to 
the perimeter dimensions of the electrical conductor delivering electrical 
signals to that field of conductive adhesive. This problem is one of 
current density. Since current density decreases significantly when 
traveling transversely even several millimeters through a field of 
conductive adhesive, it has been found in the present invention that it is 
important that the distance traveled by the current be minimized. The 
electrodes of the present invention minimize the distance traveled by the 
current to only a few millimeters or less of the thickness of the field of 
conductive adhesive. 
In the present invention, the current density of TENS administration is 
substantially uniform due to the construction of the electrode such that 
the perimeter of the electrically conductive surface is beyond the 
perimeter of the field of conductive adhesive which the conductor 
contacts. Thus, the maximum distance through which current must travel is 
through the thickness of the conductive adhesive between the electrically 
conductive surface and mammalian skin. 
Embodiments of the invention are described with reference to the following 
drawings.

EMBODIMENTS OF THE INVENTION 
FIGS. 1 and 2 are bottom and side plan views, respectively, of one 
embodiment of an intraoral-procedures TENS electrode 10 of the present 
invention. From the surface farthest away from mammalian skin, electrode 
10 comprises a non-conductive flexible backing 12 having an electrically 
conductive surface 14 contacting both a field 15 of conductive adhesive 
and two opposing fields 16 and 17 of biocompatible pressure sensitive skin 
adhesive. Not shown is a release liner that contacts fields 15, 16, and 17 
of adhesive when electrode 10 is not in use. 
Flexible backing 12 comprises a tab portion 18 and a pad portion 19. Both 
tab portion 18 and pad portion 19 have electrically conductive surface 14, 
but field 15 of conductive adhesive contacts only pad portion 19. Tab 
portion 18 is suitable for releasable attachment to a electrical connector 
that delivers the TENS administration. 
Pad portion 19 has a perimeter defined by edges 21, 22, 23, and 24. By 
comparison, field 15 of conductive adhesive has a perimeter defined by 
edges 25, 26, 27, and 28. The surface area of field 15 of conductive 
adhesive within edges 25-28 contacts the surface area of pad portion 19 
within edges 21-24 of pad portion 19, such that the surface area of the 
pad portion of electrically conductive surface 14 is equal to or greater 
than the surface area of field 15 of conductive adhesive and such that the 
perimeter dimensions of the field 15 of conductive adhesive are within the 
perimeter dimensions of the pad portion 19 of the electrical conductive 
surface. 
The significance of the perimeter dimensions of electrically conductive 
surface 14 relative to field 15 of conductive adhesive has been previously 
summarized in the features of the invention. A substantially uniform 
current density has been achieved by electrode 10 of the present invention 
because, while field 15 of conductive adhesive is conductive, it is also 
more resistant to transmission of electrical signals to mammalian skin 
than electrically conductive surface 14. Based on the principles of Ohm's 
Law, the preferred delivery of TENS treatment to mammalian skin should be 
the path of least resistance. Constructing electrode 10 such that the 
maximum delivery path for TENS electrical signals is the thickness of the 
field 15 of conductive adhesive minimizes the resistance encountered in 
the delivery of TENS treatment. 
Thus, a TENS electrode of the prior art with perimeter dimensions of 
conductive adhesive exceeding perimeter dimensions of an electrical 
conductor contacting that conductive adhesive provides an unwanted high 
current density in a narrow region of the surface area of the electrode, 
causing uncomfortable sensations during TENS administration. The 
undesirable high peak of current density could cause such pain for the 
mammalian patient as to challenge the pain of intraoral-procedures itself. 
Fields 16 and 17 of biocompatible skin adhesive are not ionically 
conductive as is field 15 but are preferably at opposing locations to 
assist in the maintenance of adhesive contact of electrode 10 to skin of a 
mammalian patient. The opposing locations proximal and distal to tab 
portion 18 provide a relatively high level of adhesion to mammalian facial 
skin. In several mammalian species facial skin (as opposed to non-facial 
skin) has a high concentration of oil secreting glands that can disrupt 
continued adhesion of electrode 10. Since during TENS administration, 
mammalian patients can perceive that electrode 10 is becoming dislodged, 
assurance of adhesion of electrode 10 to the face throughout the intraoral 
procedure is important. 
Unlike TENS electrodes of the prior art, use of two electrodes 10 can be 
adhered to a mammalian face to assist intraoral-procedures. Unexpectedly, 
location of electrodes 10 as an active electrode and a return electrode 
both extraorally on the face of a patient can provide pain relief 
intraorally within the jaw and mouth of the patient. While the principles 
are not completely understood, and not being limited to any particular 
theory, using two electrodes 10 can provide effective pain relief during 
intraoral-procedures. 
Selection of materials to construct electrode 10 are known to those skilled 
in the art of biomedical electrode construction. U.S. Pats. Nos. 4,352,359 
(Larimore); 4,524,087 (Engel); 4,539,996 (Engel); 4,554,924 (Engel); 
4,848,348 (Carim); 4,848,353 (Engel); 5,012,810 (Strand et al.); 5,133,356 
(Bryan et al.); co-pending and co-assigned U.S. patent application Ser. 
No. 07/686,049 (Anderson et al.); co-pending and co-assigned U.S. patent 
application Ser. No. 07/792,442 (Duan et al.); and co-pending and 
co-assigned U.S. patent application Ser. No. 07/792,957 (Uy et al.) all 
describe suitable materials for the construction of biomedical electrodes 
useful for TENS treatment, and all are incorporated by reference as if 
fully rewritten herein. 
Of the numerous electrically nonconductive materials known to those skilled 
in the art, presently preferred for backing material 12 are polyester 
films of about 0.01 mm thickness commercially available as "Melinex" 
branded films (e.g., 329 and 339) from ICI Americas of Hopewell, Va. 
Preferably, the film can be treated with a corona treatment to improve the 
adhesion of the electrically conductive surface to the backing material. 
Of the numerous electrically conductive materials known to those skilled in 
the art, inks containing electrical conductive particles such as graphite 
or metals are useful with metal-containing inks being preferred. Presently 
preferred for electrically conductive surface 14 is a silver loaded ink 
"N-30" ink or a silver/silver chloride "R-300" ink, both commercially 
available from Ercon, Inc. of Waltham, Mass. 
Of the numerous conductive adhesives known to those skilled in the art, 
presently preferred for field 15 of conductive adhesive are those 
conductive adhesives as described in the table at Column 16 of U.S. Pat. 
No. 5,012,810 (Strand et al.) and as disclosed in U.S. Pat. Nos. 
4,524,087; 4,539,996; 4,848,353; and 4,554,924 (all Engel); co-pending and 
co-assigned U.S. patent application Ser. No. 07/792,442 (Duan et al.); and 
co-pending and co-assigned U.S. patent application Ser. No. 07/792,957 (Uy 
et al.). Presently preferred for field 15 of conductive adhesive is an 
acrylic acid/N-vinyl-pyrrolidone copolymer plasticized with glycerol 
prepared according to the disclosure of U.S. Pat. No. 4,848,353 (Engel), 
which is incorporated by reference herein. The adhesive preferably 
comprises about 10 weight percent acrylic acid monomer, about 10 weight 
percent N-vinyl-pyrrolidone, about 51 weight percent glycerol, about 0.12 
weight percent guar gum, about 3 weight percent sodium hydroxide, about 25 
weight percent water, about 0.07 weight percent benzildimethylketal 
photoinitiator, and about 0.12 weight percent 
triethylene-glycol-bis-methacrylate chemical crosslinker prepared 
according to Example 1 of U.S. Pat. No. 4,848,353. 
Of the numerous biocompatible skin adhesives known to those skilled in the 
art, presently preferred for fields 16 and 17 of adhesive are acrylate 
pressure sensitive adhesives. Acrylate ester copolymer adhesives are 
particularly preferred. Such materials are generally described in U.S. 
Pat. Nos. 2,973,286; Re 24,906; Re 33,353; 3,389,827; 4,112,213; 
4,310,509; 4,323,557; 4,732,808; 4,917,928; 4,917,929; and European Patent 
Publication 0 051 935, all incorporated herein by reference. Presently 
preferred is a pressure sensitive adhesive tape commercially available as 
No. 1522 pressure sensitive medical tape from the Medical Specialties 
Department of the Consumer and Professional Health Care Division of 
Minnesota Mining and Manufacturing Company of St. Paul, Minn. 
Now referring to FIGS. 3-5, bottom plan views (as modified with fields of 
adhesive removed), three alternative embodiments of the present invention 
having two TENS channels of intraoral stimulation are described. 
Electrodes 30, 40, and 50 each differ from electrode 10 previously 
described in that there are two channels of TENS adminstration created by 
electrically conductive surfaces 34a, 44a, 54a, respectively, for one 
channel and electrically conductive surfaces 34b, 44b, and 54b, 
respectively, for the second channel. Thus, tab portions 38a, 48a, and 
58a, respectively, and pad portions 39a, 49a, and 59a, respectively, 
connect to one channel, while tab portions 38b, 48b, and 58b, 
respectively, and pad portions 39b, 49b, and 59b connect to a second 
channel. 
The embodiments of FIGS. 3-5 differ based on the placement of fields of 
biocompatible skin adhesive. In FIG. 3, a single strip 36 of biocompatible 
skin adhesive bisects the electrically conductive surfaces 34a and 34b. 
Fields of conductive adhesive (not shown) reside in contact with the 
surfaces 34a and 34b. In FIG. 4, strip 46 corresponds to strip 36 in FIG. 
3, and electrode 40 further has a strip 47 of biocompatible skin adhesive 
proximal to tab portions 48a and 48b for greater assurance of adhesion 
during TENS treatment. FIG. 5 also shows the separation of channels 
between pad portions 59a and 59b using strip 56. Opposing strips 57a and 
57b of biocompatible skin adhesive in FIG. 5 correspond to fields 16 and 
17 of adhesive shown in FIGS. 1 and 2. 
In each embodiment of FIGS. 3-5, the principle of the invention of 
perimeter dimensions is retained. Indeed, the total of the conductive 
adhesive surface areas is less than the total of the electrically 
conductive surfaces' areas, and the surface area of each respective field 
of conductive adhesive is no greater than the surface area of its 
respective pad portions 39a, 39b, 49a, 49b, 59a, or 59b. Further, each 
field of conductive adhesive has a perimeter dimension within the 
perimeter dimension of its respective pad portions 39a, 39b, 49a, 49b, 
59a, or 59b. 
Electrodes 30, 40, and 50 can be constructed from materials selected by 
those skilled in the art in a similar manner to those selected for 
electrode 10. Preferred materials for each component described for 
electrode 10 apply also to electrodes 30, 40, and 50. 
Electrodes 30, 40, and 50 are advantageous because only one medical device 
is employed for two purposes. Traditionally, two devices have been 
required, one for each electrode purpose. Electrodes 30, 40, and 50, each 
having two channels of TENS administration, provide a time-savings and 
convenience to the health care provider while reducing cost since only one 
dual channel connector is required. Further, for the mammalian patient, 
less facial tissue is being stimulated using one dual channel electrode 
than if two single channel electrodes were used. With less facial tissue 
being stimulated, the mammalian patient generally experiences fewer 
tingling sensations, increasing comfort and augmenting pain control during 
the intraoral procedure. 
Now referring to FIGS. 6-8, all bottom plan views, three alternative 
embodiments of intraoral TENS electrodes of the present invention are 
described. Like electrodes 30, 40, and 50, these electrodes 60, 70, and 80 
each have two channels, an active channel and a return channel. Unlike 
electrodes 30, 40, and 50, electrodes 60, 70, and 80 are designed for 
intraoral TENS administration. 
These embodiments of the present invention provide intraoral TENS 
electrodes 60, 70, and 80, each comprising at least one active electrode 
pad 62, 72, and 82, respectively, and at least one return electrode pad 
64, 74, and 84, respectively, integrally joined to a common carrier, 61, 
71, and 81, respectively. Each electrode pad 62, 64, 72, 74, 82, and 84 
has a tab portion 66, 68, 76, 78, 86, and 88, respectively, and a pad 
portion 67, 69, 77, 79, 87, and 89, respectively, such that each tab 
portion has sufficient length to extend extraorally. Optionally, the 
common carrier is a backing material having a pressure sensitive adhesive 
thereon. Typically the common carrier is useful for adhesion to the gloved 
hand of a dental or oral practitioner for placing the TENS electrode 
intraorally. 
Of the three embodiments, electrode 80 is preferred. Optionally, electrode 
80 has a notch 83 in common carrier 81 between pads 82 and 84 to permit 
alignment of electrode adjacent to an injection site, preferably within 
notch 83. 
Electrodes 60, 70, and 80 need not have both the active and return pads 
mounted on a common carrier. Electrodes 60, 70, and 80 can be split along 
the long axis to provide a separation of active and return TENS 
administration sites, including placement of either the active pad or the 
return pad intraorally and the other extraorally, or the placement of both 
pads intraorally in separate locations. In these embodiments, presence of 
the pressure sensitive adhesive on the backing material facilitates 
separated placement of the pads in adjustable locations for comfort and 
effectiveness. 
Referring to FIG. 9, a sectional view of the embodiment of FIG. 8 along 
lines 9--9 is shown for pad 84, although the sectional view also 
demonstrates the construction of pad 82 as well as the embodiments of 
FIGS. 6 and 7. Pad 84 of electrode 80 has a flexible backing 92 comprising 
a tab portion 88 and a pad portion 89 and is adhered to common carrier 81. 
Both tab portion 88 and pad portion 89 have electrically conductive 
surfaces 94, but field 95 of conductive adhesive contacts only pad portion 
89. Tab portion 88 is suitable for releasable attachment to an electrical 
connector that delivers the TENS administration. Covering field 95 at 
portions other than the distal end of pad 84 is a non-conductive layer 96 
such as a single-coated pressure sensitive medical tape, so that field 95 
only resides at the distal end of electrode pad 84. Covering common 
carrier 81 is a field of biocompatible pressure sensitive adhesive 98 to 
permit pad 84 to be adhered to glove or hand of a health care 
practitioner, or an applicator, for intraoral placement of electrode 80. 
Alternatively, field 95 has sufficient adhesiveness to permit electrode 80 
to adhere to less moist portions of the intraoral cavity, such as the soft 
palette. 
Pad portion 89 has perimeter dimensions that at least exceed perimeter 
dimensions of field 95 in accordance with the principles of the present 
invention as described with respect to electrode 10 above. 
Electrodes 60, 70, and 80 can be constructed from materials selected by 
those skilled in the art in a similar manner to those selected for 
electrode 10, with the addition of non-conductive layer 96 being 
constructed from a single-coated pressure sensitive medical tape 
commercially available as No. 1525L medical tape from the Medical 
Specialties Department of the Consumer and Professional Health Care 
Division of Minnesota Mining and Manufacturing Company, and the addition 
of field 98 being constructed from a double-coated pressure sensitive 
medical tape such as No. 1522 tape described above. Preferred materials 
for each component described for electrode 10 apply also to electrodes 60, 
70, and 80. 
Referring to FIG. 10, which is a cross-sectional view of an alternative 
embodiment of an intraoral TENS electrode of FIG. 8 in conjunction with an 
instrument to assist placement of the TENS electrode intraorally. 
Electrode 100 is adhered to a shaft 101 providing support for both active 
electrode pad 102 and return electrode pad 104 with pad portions 106 and 
108, respectively, extending from head 105 at the end of shaft 101. The 
arrangement of active electrode pad and return electrode pad to head 105 
is similar to the arrangement of electrode 80. Optionally on the surface 
of head 105 (not shown) is a field of conductive adhesive that assists in 
the intraoral delivery of TENS treatment. 
Selection of materials for the various components of electrode 100 can be 
made from materials known to those skilled in the art. 
Shaft 101 can be made from autoclavable polymers such as 
acrylonitrile-butadiene-stryene (ABS), polycarbonate, polysulfone, 
polyethersulfone, or polyetherimide polymers. Presently preferred polymers 
are injection-molded polyetherimide or polyethersulfone polymers. 
Electrode pads 102 and 104 can be made from the same materials as employed 
for electrodes 10, 30, 40, and 50. Head 105 can be made from the same 
material as shaft 101. The field of pressure sensitive adhesive can be 
made from the same pressure sensitive adhesives as employed in electrodes 
10, 30, 40, or 50. The field of conductive adhesive can be made from the 
same conductive adhesives as employed in electrodes 10, 30, 40, and 50. 
Features of intraoral electrodes of the present invention include the 
following. Active and return electrode pads are parallel and in the same 
plane. Active and return electrode pads are attached to a common carrier, 
preferably in a shaft such as shaft 101 terminating at a head such as head 
105. The pad portions are leads that are an integral part of the electrode 
pads and extend extraorally to connect to the electrical stimulation unit. 
The integral electrode pads and leads have an adhesive thereon that can 
adhere to a gloved hand or to the surface of the head of an instrument, 
making the electrode a disposable item while permitting reuse of the head 
and shaft after sterilization. The pad can deliver TENS treatment through 
the pad portions at the exposed surface of the head, either through a 
conductive adhesive or without a conductive adhesive. The active and 
return electrode pads are configured as shown in FIGS. 6-8 for maximum 
uniform pain control at the treatment site. A single electrode connector 
of the present invention described below can be used to connect the 
intraoral electrode to the TENS stimulation unit, which minimizes the 
number of connections and wires in and about the oral cavity during 
intraoral-procedures. 
Now referring to FIGS. 11 and 12, top and side plan views, respectively, of 
a connector of the present invention for use with a TENS electrode of the 
present invention is described. All electrodes 10, 30, 40, 50, 60, 70, 80, 
and 100 require firm and unmistakable engagement with the electrical 
stimulation unit to maintain electrical connection for TENS treatment and 
continued anesthesia during intraoral-procedures. The respective tab 
portions of the electrodes are particularly suited for connectors that 
surround the tab portions and firmly and electrically contact the 
electrically conductive surfaces of such tab portions. 
To assure mechanical connection with connector 110, the respective tab 
portions of the electrodes of the present invention can be modified to 
provide a slot opening 111, cut on two, three, or four sides, for 
mechanical engagement of connector 110 when electrical connection is 
desired. 
Connector 110 improves upon a connector shown and described in U.S. Pat. 
No. 4,842,558 (Strand), the disclosure of which is incorporated by 
reference herein. Connector 110 has a housing 112 having an opening 114 
for insertion of each tab, a slide 116 moveable within the housing to 
contact a slot opening 111 in an electrode tab portion, a ridge 118 
extending from the slide to extend through the slot opening 111 of the tab 
at the point of contact with the tab, and a receptacle 120 in the housing 
112 for receiving the ridge after ridge 118 has been moved to a position 
where it is extending through the tab. 
Slot opening 111 in the tab portion can be completely open with the cut 
portion (slot portion of the backing) removed or the slot portion can be 
cut on three sides. In the latter instance, slot opening 111 would be 
pushed by ridge 118 on slide 116 into the corresponding receptacle 120. In 
either instance, the tab portion of an electrode of the present invention 
would be securely held in the connector 110. 
Electrodes 30, 40, 50, 60, 70, 80, and 100 each comprise both an active 
electrode channel and a return electrode channel. The proximity of the two 
channels on one electrode permits a single connector to be employed 
according to the present invention. FIG. 13 shows a top plan view of an 
alternate embodiment of a connector of the present invention. Connector 
130 differs from connector 110, in that connector 130 has two channels 
corresponding to the two channels of electrodes 30, 40, 50, 60, 70, 80, 
and 100. Connector 130 has two electrical pathways within housing 132 such 
that two electrical pathways on slide 136 electrically and mechanically 
contact corresponding channels through opening 134 on electrode tab 
portions. Use of connector 130 allows one connector to attach to a single 
electrode yet provides the requisite two channels for TENS administration. 
An elongated applicator 140 as shown in FIGS. 14-16 has an elongated, 
cylindrical shaft 142. One end of the shaft 142 is integrally connected to 
a first cylindrical neck 144, while the opposite end of the shaft 142 is 
integrally connected to a second cylindrical neck 146. Both of the necks 
144, 146 extend at an angle relative to the longitudinal axis of the shaft 
142. The first neck 144 is integrally connected at its outer end to a 
first head 148, while the second neck 146 is integrally connected at its 
outer end to a second head 150. 
As illustrated in FIG. 14, the first head 148 includes a bifurcated end 151 
that presents a first end section 152, a second end section 154 and a 
generally V-shaped channel 156 located between the spaced apart end 
sections 152, 154. An outer wall 158 of the first head 148 extends away 
from the end sections 152, 154 in a flat plane, and is integrally joined 
to a curved wall that presents a second end 160 opposite the bifurcated 
end 151. 
The second head 150 of the applicator 140 has a first bifurcated end 153 
similar to the first bifurcated end 151 of the head 148. The first 
bifurcated end 153 is located on its outermost end of the second head 150 
(i.e., the end of the second head 150 remote from the second neck 146). 
The second head 150 also has an outer wall 162 that extends in a flat 
plane from the first bifurcated end 153 to a second bifurcated end 155 
located next to the neck 146. 
The applicator 140 can be made of the same materials as mentioned earlier 
in connection with shaft 101 illustrated in FIG. 10. Preferably, the 
applicator 140 is integrally molded of a clear, translucent or opaque 
aromatic liquid crystal polyester such as VECTRA A530 (from 
Hoechst-Celanese); an alternative material is an acetal resin such as 
DELRIN (from E.I. dupont de Nemours & Co.). The applicator is sterilized 
by cold sterilization or by an autoclave process. 
FIG. 16 depicts an intraoral-procedures TENS assembly that comprises the 
applicator 140 along with an intraoral electrode 170. Electrode 170 is 
substantially the same as electrode 80 described above in connection with 
FIGS. 8 and 9, and as a consequence a detailed description of each element 
of the electrode will not be repeated. 
Biocompatible pressure sensitive adhesive 173 (similar to adhesive 98), 
covers a common carrier and provides a means to releasably connect the 
electrode 170 to shaft 142 as well as to the outer wall 158 of the first 
head 148. Typically, the electrode 170 is spaced from the neck 144 at the 
location marked "A" in FIG. 16 as it extends about neck 144, to facilitate 
flat, firm contact of the electrode 170 with both the outer wall 158 of 
the first head 148 as well as with the side of the applicator shaft 142 
that is remote from the first head 148. Other connecting means are also 
possible, such as a mechanical clip or interlocking structure. 
As shown in FIGS. 16-17, a notch 172 of the electrode 170 is located 
between a first pad portion 174 and a second pad portion 176. Preferably, 
the notch 172 is aligned with the channel 156 when the applicator 140 and 
the electrode 170 are assembled together. Such alignment facilitates use 
of the channel 156 and the notch 172 as guides to assist in alignment of 
the electrode 170 to a particular location in the oral cavity. For 
example, the needle of a syringe containing an anesthetic may be guided by 
the channel 156 and the notch 172 toward an injection site in the oral 
cavity that is directly between the pad portions 174, 176. 
Advantageously, adhesive 173 retains the electrode 170 in place against the 
applicator 140, such that electrode 170 does not normally obstruct the 
view of the practitioner toward the injection site. In this regard, the 
applicator 140 together with the electrode 170 can be oriented as desired 
in the oral cavity in such a manner as may be most useful for the 
situation at hand. 
The electrode 170 may be connected to the applicator 140 in a variety of 
different configurations, and the illustration in FIG. 16 shows only one 
example. As an alternative, the orientation of electrode 170 may be 
reversed such that the notch 172 is in alignment with the channel of the 
first bifurcated end 153 of the second head 150. As another alternative, 
the pad portions 174, 176 may be placed on the second head 150 in such an 
orientation that the notch 172 is in alignment with the channel of the 
second birfurcated end 155 of second head 150. The larger head 148 is 
useful for placement of the pad portions 174, 176 on the maxillary 
incisive papilla, while the smaller head 150 is useful for placing the pad 
portions 174, 176 in remaining areas of the patient's oral cavity. 
Electrode 170 has tab portions 180, 182 (FIG. 17) that are leads and that 
are an integral part of the electrode portions 176, 174 respectively. FIG. 
17 also illustrates a flexible backing (similar to backing 92) upon which 
the pad portions 174, 176, tab portions 180, 182 as well as the common 
carrier are mounted. A field of conductive adhesive (similar to field 95) 
covers the pad portions 174, 176. 
Preferably, the areas of the outer walls 158, 162 are each equal to or 
slightly smaller than the area of the electrode 170 adjacent pad portions 
174, 176. Optionally, the electrode 170 overhangs the bifurcated end of 
the adjacent applicator head by a distance of 2 to 4 mm, to facilitate 
conforming the shape of pad portions 174, 176 to the patient's tissue or 
skin in regions where the tissue or skin is curved. 
The invention shown in FIG. 16 is especially useful for dental or medical 
procedures where local anesthesia is needed for only a relatively short 
time. Examples include injections, tooth extractions, or tooth restorative 
procedures. Applicator 140 could be held by the practitioner, or 
optionally by the patient. When the assembly shown in FIG. 16 is used 
intraorally, tab portions 180, 182 and applicator shaft 142 are of lengths 
sufficient to extend extraorally when the pad portions 174, 176 are in 
place in the oral cavity. 
Various embodiments of the invention have been described. The following 
claims and their equivalents provide a complete understanding of the 
present invention.