Instrument and Method for Administering an Injectable Anesthetic

The present invention is concerned with the field of anesthetic injection of the palatal tissue and more particularly to a method and instrument which can be readily used by dentists, for example, to deaden or eliminate the pain associated with the penetration of the needle into the relatively thin and sensitive palatal tissue. Various instruments have been proposed over the years to aid in the injection of anesthetics or the withdrawal of blood, as set forth in the following prior art patents:

None of the foregoing patents are, however, particularly concerned with injection at the palatal foramina where the nerves are exposed in the bone and the soft tissue is fibrous and taut. In the Fosdal U.S. Pat. No. 2,945,496, a dental instrument is suggested for gum tissue. In this instrument, a foot having top and bottom openings is placed on the gum tissue with only enough pressure to seal the opening for the application of suction. The upper opening in the foot is covered with a jacket of transparent material and, when the gum tissue is sucked up into the foot through the bottom opening, a hypodermic needle is inserted through the jacket and into the gum tissue to progressively feed a pain killing drug into the tissue. The Fosdal patent postulates that suction drawing the tissue into the interior of the foot causes the tissue to become taut, firm and immobile and that this preconditioning minimizes the shock of needle penetration. In effect, the instrument used applies a negative pressure which, as will become apparent, is the antithesis of what the present method teaches. The instrument requires movable tissue such as to be found in the gums but not in the thin, taut palatal tissue. The other patents cited are also considered not materially pertinent to the invention claimed, which is neither singularly nor combinatively disclosed or suggested in these prior art patents.

Another method which has been recommended is the use of a swab stick at a site adjacent the area to be injected, while the needle is inserted adjacent to the tissue which is pressed until it blanches by the swab stick. The swab stick may undesirably leave cotton fibers in the tissue and, more importantly, presses only a very small spot at one side of the tissue which is to be injected.

The method of pain alleviation utilized in the thin, and therefore very sensitive palatal tissue covering the palative bone employs a positive pressure to stimulate the surface tactile receptors of the palatal tissue to be injected to thereby "open the gate" of the pain transmitting fibers and interrupt their transmission to the brain. At the same time, a pressure anesthesia through ischemia is effected at the selected location. In using the instrument which will be described, the dentist firmly presses one of the ring ends of the instrument against the palatal tissue immediately adjacent to the foramen selected, until the tissue visibly blanches. The syringe needle is then gently inserted into the tissue through the open center of the instrument's ring, which also functions to provide a bullseye target, to a site just below the tissue surface, after which the instrument is slowly removed by drawing the exit slit in the instrument end past the needle. Thereafter a small amount of anesthetic is slowly administered until the tissue blanches slightly, after which the syringe is removed. After the initial anesthetic takes effect a few minutes later, further anesthetic may be administered without discomfort to the patient. The tissue immediately adjacent to that covering each of the remaining palatal foramina may be subsequently anesthetized in the same way. The instrument utilized in the method is a double ended instrument with one end being used for the right anterior palatine foramen and the other for the left anterior palatine foramen. Either end may be used for the naso-palatine foramen. The instrument includes a gripping base with compositely angled shanks at each end which terminate in a ring. The slit provided in each of the ring ends permits the instrument to be withdrawn past the needle, once the needle is inserted centrally through the ring into the palatal tissue.

One of the prime objects of the present invention is to provide a specialized instrument for the performance of the new method of injecting the palatal tissue in a manner which relieves the pain and resulting mental trauma associated with the administration of an anesthetic to this tissue by the needle.

Still another object of the invention is to provide an instrument which can be easily and efficiently used to inject the palatal tissue immediately adjacent that covering the exposed nerves at all of the palatal foramina, one after the other.

Still a further object of the invention is to provide an instrument which is light in weight, yet sturdy, and which further is of simple and inexpensive construction.

Other objects and advantages of the invention will be pointed out specifically or will become apparent from the following description when it is considered in conjunction with the appended claims and the accompanying drawings.

In the drawings,

FIG. 1 is a schematic under plan view of the palate showing the location of the palatal foramina relative to the teeth and gum tissue.

FIG. 2 is a top plan view of the specialized instrument utilized in the process.

FIG. 3 is a side elevational view thereof.

FIG. 4 is an end elevational view taken on the line 4--4 of FIG. 2, and with the opposite end of the instrument omitted from the view.

FIG. 5 is an end elevational view taken on the line 5--5 of FIG. 2, with the opposite end of the instrument omitted from the view.

FIGS. 6-8 are progressive fragmentary underplan views illustrating the steps which are progressively performed in practicing the method.

Referring now more particularly to the accompanying drawings wherein a preferred embodiment of the invention is disclosed, and in the first instance more particularly to FIG. 1, the upper teeth are numbered in the usual fashion and the palatal tissue is generally identified by the letter P. The right anterior palatine foramen is identified at 16 and the left anterior palatine foramen is identified at 17. The naso-palatine foramen is identified at 18.

The instrument I to now be described is of a specialized structure to aid in the administration of the anesthetic which is conventionally injected at these locations during the practice of various dental procedures requiring anesthesia of the palatal tissue. The instrument I comprises a knurled mid or base portion 18 which at its right end includes a transition portion 19 leading to the stem portion 20 of reduced diameter. A shank 21 extends angularly from the part 20 in a compound manner and terminates in a ring 22 which is flat in the sense that it is parallel with the stem portion 20 and base portion 18 in FIG. 3. Ring 22 is circular in cross-section to present a blunted, or curvilinear surface 22a to the palatal tissue. The ring opening 23 of predetermined diameter communicates with a through slit 24 of predetermined width in the terminal end of ring 22. As will be apparent from FIG. 2, the portion 19 of the instrument bears the indicia R so that the person using the instrument can readily distinguish the right and left hand ends.

At the other end of the instrument I, the intermediate base portion 18 has a similar transition portion 25 leading to a reduced diameter stem portion 26. A shank 27 then extends angularly from the portion 26 and terminates in a left end ring 28 which is parallel to the stem portion 26 and base 18 in FIG. 3. Ring 28 similarly is of circular cross-section to present a blunted outer curvilinear surface 28a to the palatal tissue and the opening 29. The ring 28 similarly has an opening 29 of predetermined diameter, and has a through slit 30 of predetermined width communicating with it.

The rings 22 and 28 are four millimeters in external diameter, and openings 23 and 29 are two millimeters in diameter. The slits 24 and 30 are one millimeter in width to provide the desired escape past the hypodermic needle. The cross-sectional diameter of the ring 23 is also one millimeter, and the length of shanks 21 and 27 is fourteen millimeters. The angle of the shanks 21 and 27 to the stem portions 20 and 26 is 135.degree. and the offset angle of the shanks 28 and 27 to the portions 20 and is 30.degree.. These angles have been found to best present the rings 24 and 28 to the palatal tissue while still providing the vision which the dentist needs to properly place the instrument ends and insert the needle through the center of the ring end in use.

In practice, the instrument is held in the left hand by a right handed operator with the right end being used at the right anterior palatin foramen and the left end being used at the left anterior palatal foramen. While either end may be used for the naso-palatine foramen, for a right handed operator, the left end is more convenient.

In practicing the method, it will be noted that in FIGS. 6-8 it is the naso-palatine foramen tissue to which the pain killing anesthetic is being administered. Prior to the time the ring 22 is applied to the tissue immediately adjacent to the foramen 18, as disclosed in FIG. 6, the dentist drys the foramen area and applies a topical anesthetic. After a time wait of approximately one minute for the surface tissue to be anesthetized, the ring 22 is pressed firmly into the palatal tissue immediately adjacent to the foramen 18 until the tissue visibly blanches. The ring end is applied at the base of the incisive papilla, just lateral of it. At this point the syringe needle 31 of the drug-containing hypodermic syringe 32 is inserted into the mouth of the patient, with the syringe needle 32 gently inserted through the open center of the opening 23 as a bullseye target to a level just below the thin tissue surface, i.e. 6-10 millimeters. The needle, which preferably is approaching the injection site at a forty-five degree angle, engages and is guided by the ring into substantially the very center of the blanched tissue for maximum patient comfort. Preferably the drug or anesthetic will be warmed just prior to injection to prevent a "burning" sensation when the anesthetic is being administered. After insertion of the needle, the instrument I is then slowly withdrawn, with slit 24 being moved past the needle 31. This is a safety measure so the dentist has a free hand at the time of anesthetic injection in case the patient gags or needs to swallow. Then the syringe plunger 33 is pressed and a small amount of anesthetic is very slowly administered until the tissue blanches slightly. Following this, the needle 31 is removed. A few minutes later, further anesthetic may be administered after the initial amount has fully deadened the tissue. The method is effective, simple to implement, and of great benefit to the patient. The anterior foramina 16 and 17 are treated in the same way with the ring end being pressed against the tissue immediately anterior to the foramen 16 or foramen 17. Because there is no papilla, the site is selected as the area midway between the rearmost and next rearmost molars, and halfway in the palatal tissue between the gum line and the longitudinal midpoint of the palatal tissue. The normal depth of insertion used is 10-15 millimeters.

Although preferred embodiments of the invention have been illustrated in the accompanying drawings and described in the foregoing detailed description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions of parts and elements without departing from the spirit of the invention which is defined in the following claims.