Patent Publication Number: US-2023158253-A1

Title: Anesthesia applicators/injectors for dental and other applications and methods of use

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. patent application Ser. No. 16/512,102 filed Jul. 15, 2019, entitled “ANESTHESIA APPLICATORS/INJECTORS FOR DENTAL AND OTHER APPLICATIONS AND METHODS OF USE,” which is a continuation application of U.S. patent application Ser. No. 15/632,197 filed Jun. 23, 2017, entitled “ANESTHESIA APPLICATORS/INJECTORS FOR DENTAL AND OTHER APPLICATIONS AND METHODS OF USE,” which is a continuation application of U.S. patent application Ser. No. 14/679,321 filed Apr. 6, 2015, now U.S. Pat. No. 9,687,606, entitled “ARTICULATING APPLICATORS/INJECTORS FOR ADMINISTRATION OF LIQUID ANESTHETIC AND OTHER LIQUID,” which is a continuation-in-part of application of U.S. patent application Ser. No. 13/938,686 filed Jul. 10, 2013, now U.S. Pat. No. 9,713,680, entitled “ANESTHESIA APPLICATORS/INJECTORS FOR DENTAL AND OTHER APPLICATIONS AND METHODS OF USE,” The contents of the aforementioned applications are hereby incorporated by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to dental instruments and more particularly to devices and methods of use for injecting a liquid anesthetic during periodontal or other dental procedures, but which can be used for other procedures involving the injection of a liquid into tissue in the body of a living being. 
     BACKGROUND OF THE INVENTION 
     As is known, the periodontal ligament injection (“PDL”) is an accepted intraligamentary injection modality for primary anesthesia for one or two teeth. It is also used as a supplement to infiltration or block techniques. The PDL technique entails use of a small amount of anesthetic to produce instant anesthesia. In particular, an ultra-short needle is placed in the gingival sulcus on the mesial and distal surfaces and advanced along the root surface until resistance is met. Then the needle is advanced further to make contact and dispense more anesthetic liquid. This allows the numbing of the tooth without the patient feeling the process. The technique&#39;s primary advantage is that it provides pulpal anesthesia for 30 to 45 minutes without an extended period of soft tissue anesthesia. Moreover, because only a small amount of liquid anesthetic is injected at the site of the periodontal ligament (which inherently has limited blood circulation) PDL can be used in patients with bleeding disorders. 
     Various syringes and techniques have been proposed and used in the prior art for effecting PDL and there are even computer controlled anesthetic delivery systems, e.g., “The Wand” offered by Milestone Scientific, of Livingston, N.J. Such prior art syringes, techniques and systems, while suitable for their intended purposes, nevertheless leave something to be desired from one or more of the following standpoints: trauma, patient fear of needles, simplicity, cost, ease of use and effectiveness. Thus, a need exists for a low cost, simple device for readily accomplishing a periodontal ligament injection with minimal, if any patient discomfort. The subject invention addresses that need. 
     In addition, the subject invention also provides a device and method of use for injecting a liquid anesthetic into the gum and underlying tissue of a patient with less pain than accomplished with conventional needle syringes. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the invention there is provided an applicator for effecting an intraligamentary injection of a liquid anesthetic into the gingival sulcus of a patient. The applicator basically comprises a body member having an elongated tip. The tip is a generally planar, thin member having an atraumatic free end and a passageway extending therethrough and terminating at the free end of the tip. The applicator is arranged to be secured to a source of liquid anesthetic, whereupon the liquid anesthetic may be selectively introduced into the applicator. The free end of the elongated tip of the applicator is arranged for producing a substantially fluid-tight interface with the anatomic structures at the gingival sulcus, whereupon the liquid anesthetic may be forced from the applicator through the passageway out of the open free end of the tip to enter into the gingival sulcus so that it is directed downward along the root of the adjacent tooth and is prevented from flowing upward and outward. 
     In accordance with another aspect of this invention there is provided an applicator for effecting an injection of a liquid anesthetic into the tissue of a person. That applicator basically comprises a coupling, an elongated member having a distal end portion in the form of a hollow skirt having a free edge, and an elongated cannula having an open distal end located within the skirt proximally of the free edge. The open distal end of the cannula is sharp. The coupling is arranged for securing the applicator to a source of liquid anesthetic, whereupon the liquid anesthetic may be selectively introduced within the cannula and from there into the hollow skirt. The hollow skirt is formed of a flexible material suitable for producing a substantially fluid-tight interface with the tissue to locally anesthetize the tissue when the liquid anesthetic is introduced into the hollow skirt. The sharp distal end of the cannula is movable relative to the free edge of the hollow skirt to enable the sharp distal end to penetrate the tissue to inject the liquid anesthetic into the tissue. The applicator may optionally include electrodes forming a portion of a transcutaneous electrical nerve stimulation (TENS) unit. 
     In accordance with another aspect of this invention there is provided a method for effecting an intraligamentary injection of a liquid anesthetic into the gingival sulcus of a patient. That method basically entails providing an applicator comprising an elongated member having a hollow interior, an open distal free end, and a portion located proximally of the open distal free end in communication with the hollow interior. The open distal free end of the elongated member is formed of a resilient and somewhat conformable material. The open distal free end of the elongated member is introduced into the gingival sulcus to engage the anatomic structures at the gingival sulcus wherein the resilient and conformable material at the open distal free end produces a substantially fluid-tight interface thereat. A liquid anesthetic is provided into the hollow interior of the elongated member and through the open distal free end into the gingival sulcus so that the liquid anesthetic is directed downward along the root of the adjacent tooth and is prevented from flowing upward and outward by the fluid-tight interface. 
     In accordance with another aspect of this invention there is provided a method for effecting an injection of a liquid anesthetic into the tissue of a person. The method basically entails providing an applicator having a distal end portion in the form of a skirt having hollow interior and a peripheral free edge. The applicator also comprises an elongated cannula having an open distal end located within the skirt proximally of the free edge. The open distal end of the cannula is sharp. The hollow skirt is formed of a flexible material. The free edge of the hollow skirt is placed into engagement with the tissue of the person, whereupon the flexible material at the free end of the skirt produces a substantially fluid-tight interface with the tissue. Liquid anesthetic is provided into the hollow interior of the skirt and into engagement with a portion of the tissue bounded by the peripheral free edge of the skirt to anesthetize the tissue thereat. The sharp distal end of the cannula is moved relative to the free edge of the hollow skirt to cause the sharp distal end to penetrate the portion of the tissue to inject the liquid anesthetic therein. The applicator may optionally include electrodes forming a portion of a transcutaneous electrical nerve stimulation (TENS) unit so that the unit may be operated during the injection procedure. By way of example, but not limitation, instead of providing the liquid anesthetic into the hollow interior of the skirt to anesthesize the tissue thereat, the TENs unit can be operated to anesthesize the tissue, whereupon after the tissue has been anesthesized the cannula may be moved to cause its sharp end to penetrate the tissue. The tissue may comprise the gum and underlying tissue of a dental patient or any other tissue of a person. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is an isometric view of one exemplary syringe including an anesthesia applicator or injector constructed in accordance with this invention for periodontal ligament injection (intraligamentary injection); 
         FIG.  2    is an enlarged end view of the applicator shown in  FIG.  1   ; 
         FIG.  3    is an enlarged side elevation view of the applicator shown in  FIG.  1   ; 
         FIG.  4    is an enlarged top plan view of the applicator shown in  FIG.  1   ; 
         FIG.  5    is a greatly enlarged illustration, partially in section, of the exemplary anesthesia applicator/injector of  FIG.  1    shown in the process of performing a periodontal ligament injection; 
         FIG.  6    is a partial sectional view of an alternative anesthesia applicator/injector constructed in accordance with another aspect of this invention, e.g., an injector for penetrating oral tissue; 
         FIG.  7    is a partial sectional view of still another alternative anesthesia applicator/injector constructed in accordance with another aspect of this invention, e.g., a device like that of  FIG.  5    but including a electrodes of a transcutaneous electrical nerve stimulation (TENS) unit to facilitate further pain reduction; and 
         FIG.  8    is an illustration, similar to the illustration of  FIG.  4   , but showing the applicator/injector of  FIG.  5    in the process of performing an injection of through the gingiva. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the various figures of the drawings wherein like reference characters refer to like parts, there is shown in  FIG.  1    at  20  an applicator or injector mounted constructed in accordance with one exemplary embodiment of this invention shown mounted on a syringe  22  for use in a periodontal procedure. The applicator can be a separate unit or may form an integral part of the syringe. In either case the applicator is connected to the syringe by means of a coupling. In the exemplary embodiment shown in  FIGS.  1 - 4    the applicator is an integral device which is arranged to be mounted on the syringe. The applicator includes a passageway (to be described later) therethrough for enabling the liquid anesthetic to flow therethrough. The syringe  22  can be of any suitable construction so that a liquid anesthetic can be located within a chamber (not shown) in it to be forced from the chamber through into the applicator when desired. To that end the exemplary embodiment of the syringe  22  includes a plunger  24  which when depressed forces the liquid anesthetic out of the syringe&#39;s chamber through a coupling (not shown) and into the applicator  20 . 
     It should be pointed out that the applicator  20  may be used with devices, other than a syringe. For example, it can be used with any controlled anesthetic delivery system, like the “The Wand”, identified above or with any other equipment, e.g., an electric pump system, arranged to provide a liquid anesthetic under some force. 
     As best seen in  FIGS.  2 - 4   , the applicator  20  basically comprises a hollow proximally located body section  26  from which an elongated tip  28  projects. The tip  28  is a thin, generally planar member which has a generally rectangular profile in cross-section. The body section includes a proximally located chamber  30  ( FIGS.  3  and  4   ) and a distally located chamber  32 . The chamber  30  is arranged to receive a bolus of the anesthetic from the syringe when the syringe is actuated. The chamber  30  tapers downward in the distal direction in two sections,  30 A and  30 B, with the taper in section  30 B being more severe than the taper of section  30 A. The chamber  32  is in fluid communication with the chamber  30  and is located distally thereof. The chamber  32  serves to produce a jet of the anesthetic liquid from the chamber  30 . To that end, the chamber  32  is of a constant diameter, which is less than the diameter of the chamber  30 . The chamber  32  extends into the proximal portion of the tip  28 . 
     The tip  28  is preferably formed of a somewhat flexible material, e.g., polypropylene or polycarbonate or any other suitable plastic or other material. A small diameter passageway  34  extends through the tip  28  from its distal end  36  to the distal end of the chamber  32 , so that the passageway  34  is in fluid communication with the chamber  32 . As best seen in  FIG.  4   , the distal end  36  of the tip  28  is rounded to be atraumatic and includes a semi-circular shaped cut  38  ( FIG.  4   ) at its distal-most point. The distal end of the passageway  34  terminates at the cut  38  and is in fluid communication therewith. 
     As mentioned above the tip  28  has a generally flat profile. More precisely, and in accordance with one exemplary preferred embodiment of the invention, the peripheral edge of the distal end portion of the tip is tapered symmetrically at  40 . This peripheral taper feature, coupled with the fact that the tip is somewhat flexible facilitates atraumatic entry of the tip into the gingival sulcus. 
     In one preferred exemplary embodiment of the invention the total length of the applicator  20  is approximately 4 cm (e.g., 2, 3, 4, 5 or 6 cm), with the length of the applicator from its distal end  36  to the proximal end of its chamber  32  being approximately 3 cm (e.g., 1, 2, 3, 4 or 5 cm). The distal portion of the tip  28  is approximately 4 mm (e.g., 2, 3, 4, 5 or 6 mm) wide and 0.5 to 1.0 mm (e.g., 0.5, 0.6, 0.7, 0.8, 0.9 or 1 mm) thick, with the diameter of the passageway  34  being approximately 0.25 mm (e.g., 0.1, 0.2, 0.25, 0.3 or 0.4 mm). The diameter of the chamber  30  at the proximal end of section  30 A is approximately 5.4 mm (e.g., 3.0, 4.0, 5.0, 5.4, 6.0 or 7.0 mm), while the internal diameter of the proximal end of the section  30 B is approximately 3.5 mm (e.g., 2.0, 3.0, 3.5, 4.0 or 5.0 mm). The diameter of chamber  32  is approximately 2.5 mm (e.g., 1.0, 2.0, 2.5, 3.0 or 4.0 mm), while its length is approximately 1.7 cm (e.g., 0.5, 1.0, 1.7, 2.0, 2.5 or 3.0 cm). 
     It should be pointed out that the foregoing dimensions are merely exemplary and other shapes and sizes of the applicator  20  are contemplated so long as they enable the distal end of the applicator to be atraumatically introduced into the gingival sulcus along the periodontal ligament to engage the anatomic structures at the gingival sulcus to inject the liquid anesthetic therein. 
     Operation of the applicator/injection can best be appreciated by reference to  FIG.  5   . In particular, as shown therein the tip  28  of the applicator  20  is arranged to be atraumatically introduced into the gingival sulcus between the tooth  10  and the gingiva (gum)  12  along the periodontal ligament  14  to engage the anatomic structures thereat. The periphery of the distal portion of the tip being tapered and somewhat flexible forms or produces a fluid tight seal with the immediately adjacent anatomic structures. Thus, when the plunger  24  of the syringe  22  is pressed inward, a jet of the anesthetic liquid produced in the chamber  32  is forced through the communicating passageway  34  out through its open distal end at the cut  38  so that the anesthetic set is directed downward along the root  16  of the adjacent tooth  10  and is prevented from flowing upward and outward by the fluid-tight interfacial seal formed by the free end of the tip. 
     As should be appreciated by those skilled in the art the use of the thin, flexible tip of the applicator  20  enables one to readily deliver an anesthetic solution through the periodontal membrane, thus doing away with the use of needles. However, it is also within the scope of the invention to place the applicator over a conventional needle and deliver the anesthetic solution through the needle and applicator while preventing the needle from contacting the patient. 
     Turning now to  FIGS.  6 - 8    there is disclosed another exemplary embodiment of an injector  120  constructed in accordance with this invention. This embodiment and variants encompassed by this invention is primarily arranged for infiltration to numb teeth, which heretofore has been accomplished by use of a sharp cannula to pierce the oral tissue adjacent the roots of the teeth to cause the teeth to numb. To that end, the applicator  120 , like the applicator  20  is arranged to be used with a syringe (e.g., it may be a separate unit arranged to be mounted on a syringe or may be an integral part of the syringe) or may be used with any controlled anesthetic delivery system, like the “The Wand”, identified above or with any other device arranged to provide a liquid anesthetic under some force. Unlike the applicator  20  of  FIGS.  1 - 4   , the applicator  120  is arranged to penetrate the gingiva to deliver the liquid anesthetic therethrough. However, like the applicator  20 , the applicator injector  120  achieves that end in an atraumatic manner. 
     As best seen in  FIG.  7   , the applicator  120  basically comprises a coupling  122 , an elongated tubular body  124  and an elongated cannula  126 . The elongated tubular body is formed of a somewhat flexible material, e.g., silicone, and has a distal end portion in the form of a hollow skirt  128  having a free edge  130 . The cannula  126  is an elongated tubular member formed of any suitable material, e.g., silicone which is more rigid, than the silicone of the body  124 . The cannula  126  has a sharpened, open distal free end  132 . The cannula  126  extends through the tubular body  124  so that its open free end  132  is in fluid communication with the hollow skirt  128 , e.g., the free end  132  may be located within the hollow skirt  128  (show) or may be retracted slightly from it but still in fluid communication with it. The hollow body  124  is mounted on the coupling  122  via a threaded engaging portion  134 . The coupling  122  includes a passageway  136  which is in fluid communication with the interior passageway of the cannula and also with the outlet passageway of the chamber in the syringe in which the liquid anesthetic is located. 
     The periphery of the free edge  130  of the skirt  128  of the applicator/injector  120  is arranged to be brought into engagement with the surface of the gingiva where the injection is to be made, like shown in  FIG.  8   , whereupon the free edge  130  of the skirt  128  forms a substantially fluid tight seal with the outer surface of gingiva  12  thereat. Accordingly, when the syringe  22  is operated, e.g., its plunger  26  depressed, the liquid anesthetic is forced out of the syringe&#39;s chamber through the coupling&#39;s passageway  136 , into the cannula  126  and out the open end  132  of the cannula, whereupon the anesthetic will be within the skirt and thus in engagement with the portion of the gingiva bounded by the periphery of the free edge of the skirt. This initial dose of the anesthetic serves to locally anesthetize the gingiva, so that once that has occurred the cannula can be used to penetrate the gingiva to a desired depth therebelow to deliver a second dose of the anesthesia, without causing the patient to experience any pain or discomfort. To that end, the cannula  126  is arranged to be moved with respect to the free edge  130  of the skirt  128  so that it can extend distally therebeyond to inject the anesthetic through the gingiva into the underlying structure after the gingiva has been locally anesthetized. For example, the cannula may be threadedly coupled to the body  124  so that its sharp free end can be extended beyond the beyond the free edge  130  of the skirt and into the underlying structure by merely twisting a portion of the applicator  120 . Alternatively, the cannula may be coupled to the body so that its sharp free end can be extended beyond the free edge of the skirt by a sliding action, instead of a twisting action. In fact, it is even contemplated that the skirt portion  128  of the body  124  may be constructed so that it is collapsible, bendable or otherwise deformable, so that the sharpened free end of the cannula can be extended therebeyond by pushing on the applicator  120  after the free edge of the skirt has engaged the gingiva and the gingiva has been locally anesthetized to cause the skirt to collapse, bend or otherwise deform. 
     In any case, the cannula is arranged to move relative to the skirt from a retracted position, like shown in  FIGS.  6  and  7   , to an extended position (not shown) wherein the sharpened free end of the cannula extends beyond the free edge  130  of the skirt through the gingiva and into the underlying anatomic structure to a desired depth, e.g., into the bone  18 , after the gingiva has been locally anesthetized by the anesthetic in the hollow skirt. At that point the plunger of the syringe can be depressed again to inject a dose of the anesthetic into that underlying anatomic structure. 
     In the interest of making the injection procedure as atraumatic as possible, the distal edge  130 , if not the whole body  124  or skirt  128 , is formed of a resilient and conformable material. Preferably, the distal free end is also somewhat rounded in shape to form an atraumatic end surface. 
     In  FIG.  7   , there is shown an alternative embodiment of an applicator/injector  220 , which is constructed similarly to the applicator  120 . Thus, in the interest of brevity the structural details of the applicator  220  which are the same as those of the applicator  120  will be given the same reference numbers and the details of their construction and operation will not be reiterated. The applicator  220  includes a pair of electrodes  222  which are located within the tubular body  124  and which are connected to a remote TENS unit (not shown) via a pair of electrical conductors (not shown). Thus the TENS unit can be operated to numb the tissue prior to the cannula&#39;s penetration of the tissue, thus further lessening the chance that the patient will experience pain during the injection procedure. 
     It should be pointed out at this juncture that the embodiments of the applicator/injectors of  FIGS.  6  and  7    are not limited to infiltration usage as just described. Hence they can be used for PDL procedures as well. For such usage the applicator has to be appropriately sized and shaped to enter the gingival sulcus. Once the distal end of the applicator/injector  120  or  220  has entered that region the syringe can be operated to inject the liquid anesthetic into the skirt  128 , where it will engage and locally anesthetize the adjacent tissue/anatomic structure. Once that small area has been exposed to the anesthetic for a sufficient time to be numbed, the cannula  126  can then be moved relative to the free edge  130  of the skirt to cause it to penetrate the underlying tissue/anatomic structure, whereupon a second dose of the anesthetic may be injected to numb the tooth. 
     Moreover the applicator  120  is not limited to dental use. Thus, it can be used to inject a liquid anesthetic (or any other liquid substance, for that matter) into any tissue of a patient atraumatically. 
     It should also be pointed out that the particular materials used to form the applicator/injectors as described above are merely exemplary of various materials which may be used. 
     Without further elaboration the foregoing will so fully illustrate my invention that others may, by applying current or future knowledge, adopt the same for use under various conditions of service.