FOR USE WHILST ADMINISTERING INJECTIONS

FIELD OF THE INVENTION

The present invention relates to a device and an associated method that may be used to temporarily anesthetise tissue at a proposed site of the administration an injection. Embodiments of the present invention find application, though not exclusively, in the field of dentistry for use when administering injections into a patient's palatal tissue and/or gum region.

BACKGROUND OF THE INVENTION

Many medical procedures require injections to be administered to patients;

however such injections often entail a substantial degree of pain and discomfort. Known prior art attempts to minimize or eradicate this pain and discomfort include a tooth anesthesia device marketed as the "STA™ System", which is marketed by Milestone Scientific. This prior art system features computerised control of the flow rate and overall dosage for delivery of local anesthesia via the periodontal ligament and associated space, through the cribriform plate and into the medullary bone. Whilst this system may be effective in reducing or eliminating the pain and discomfort of oral injections, it suffers the disadvantage of excessive complexity and expense.

U.S. Patent Nos. 4,681,101 and 5,088,925 disclose prior art devices that may be used to apply pressure to a patient's tissue to provide temporary local anesthesia.

However, the devices disclosed in these two U.S. prior art patent specifications require the medical practitioner to ascertain when the patient's tissue is blanched and this may be difficult in some circumstances and particularly when the proposed injection site is located inside the patient's mouth.

Any discussion of documents, acts, materials, devices, articles or the like which has been included in this specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed in Australia or elsewhere before the priority date of this application.

SUMMARY OF THE INVENTION

It is an object of the present invention to overcome, or substantially ameliorate, one or more of the disadvantages of the prior art, or to provide a useful alternative.

In one aspect of the present invention there is provided an anesthetic device for application to a patient at a proposed injection site, said anesthetic device including: an arm;

a substantially transparent head disposed at or adjacent a distal end of said arm, said head defining a patient abutment surface and an opposite surface; and

an aperture extending through said head from the opposite surface to the patient abutment surface, said aperture being sized for the passage there through of a hypodermic needle.

Preferably the head is constructed from a substantially transparent plastics material, which in some preferred embodiments may be, or include, any one or more of Perspex, Lexan, surgical silicone, thermoplastic acrylic resin, polymethlamethacrylate, cellulose acetate butyrate, polycarbonate and/or glycol modified polyethylene

terphthalate.

In a preferred embodiment of the anesthetic device the aperture defines a first opening at an intersection of the aperture and the opposite surface. In this embodiment the aperture defines a second opening at an intersection of the aperture and the patient abutment surface whereby the first opening is larger than the second opening. Preferably the aperture tapers from the first opening to the second opening.

A preferred embodiment includes a slot extending from the aperture to an outer edge of the head, said slot being sized for the passage there through of said hypodermic needle. Preferably the arm is shaped for application of the patient abutment surface to a position within a patient's mouth and the shape may be arcuate. In one preferred embodiment an elongate dimension of the arm defines at least one bend having a total angular divergence of between 10° and 150°. Preferably a handle is disposed at a proximal end of the arm.

In another aspect of the present invention there is provided a method of administering an injection to a patient, said method including the steps of:

providing an anesthetic device having a substantially transparent head defining an aperture extending there through;

abutting said head against said patient at a site of a proposed injection;

using the head to apply pressure to said site;

viewing said site through said substantially transparent head to ascertain if said site is blanched and therefore temporarily anesthetised; and

once said site is temporarily anesthetised, inserting a hypodermic needle through said aperture and injecting said hypodermic needle into said site.

Preferably the method also includes the steps of:

providing a slot extending from the aperture to an outer edge of the head; and whilst the hypodermic needle is injected into the site, removing the anesthetic device by causing an exposed portion of the needle to exit from the aperture via the slot.

The features and advantages of the present invention will become further apparent from the following detailed description of preferred embodiments, provided by way of example only, together with the accompanying drawings.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1 is a perspective view of a first preferred embodiment of the invention; Figure 2 is an enlarged perspective view of a head and part of an arm of the first preferred embodiment;

Figure 3 is another enlarged perspective view of a head and part of an arm of the first preferred embodiment;

Figure 4 is a perspective view of a second preferred embodiment of the invention;

Figure 5 is another perspective view of the second embodiment;

Figure 6 is a perspective view of a third preferred embodiment of the invention;

Figure 7 is another perspective view of the third embodiment;

Figure 8 is a top perspective view of a fourth preferred embodiment of the invention;

Figure 9 is an underside perspective view of the fourth embodiment;

Figure 10 is a top view of the fourth embodiment;

Figure 11 is an underside view of the fourth embodiment;

Figure 12 is a right hand side view of the fourth embodiment;

Figure 13 is a left hand side view of the fourth embodiment;

Figure 14 is a front view of the fourth embodiment;

Figure 15 is a rear view of the fourth embodiment;

Figure 16 is an enlarged partial perspective view showing the head of the fourth embodiment;

Figure 17 is an enlarged partial perspective view showing an alternative head; Figure 18 is an enlarged partial perspective view showing another alternative head.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Referring to the figures, the preferred embodiment of the anesthetic device 1 has an arm 2 and a substantially transparent head 3 disposed at a distal end of the arm 2. The head 3 defines a patient abutment surface 4, which is best shown in figure 2, and an opposite surface 5. An aperture 6 extends through the head 3 from the opposite surface 5 to the patient abutment surface 4. The aperture 6 is sized for the passage there through of a hypodermic needle. The head 3 (and optionally the remainder of the device 1) is constructed from a substantially transparent material, which in the preferred embodiment is either Perspex, Lexan or surgical silicone. However, in some alternative embodiments other transparent plastics materials may be used, such as a thermoplastic acrylic resin, a

polymethlamethacrylate, a cellulose acetate butyrate, a polycarbonate, a glycol modified polyethylene terphthalate, or a combination thereof. The use of a plastics material allows the preferred embodiment to be manufactured by means of injection moulding, or the like. This allows the preferred embodiments to be manufactured relatively inexpensively and quickly, especially as compared to the metal devices disclosed in the U.S. prior art specifications mentioned above. In some embodiments the material from which the device 1 is made has a degree of flexibility. However, in other embodiments the degree of flexibility is preferably minimised or substantially eradicated such that the device is substantially rigid.

As used in this patent specification, including in the claims, the term "substantially transparent" is to be given a broad construction. More particularly, a material is to be considered "substantially transparent" if it is possible to discern a colour change through the material from a shade of pink that is characteristic of a typical patient's gum or palatal tissue in an unblanched state to a lighter shade of pink or white that is characteristic of a patient's gum or palatal tissue when in a blanched state. That is, the term "substantially transparent" is to be construed broadly so as to include any degree of transparency, or translucency, which is sufficient for the blanching of the site of the patient to be discernable.

A first opening 7 is defined at an intersection of the aperture 6 and the opposite surface 5. A second opening 8 is defined at an intersection of the aperture 6 and the patient abutment surface 4. The aperture 6 tapers from the first opening 7 to the second opening 8 and therefore the first opening 7 is larger than the second opening 8. The relatively larger size of the first opening 7 allows for easier threading of the hypodermic needle into the aperture 6, whereas the relatively smaller size of the second opening 8 helps to increase the available area of the patient abutment surface.

A slot 9 extends from the aperture 6 to an outer edge of the head 3. The slot 9 is sized to allow the hypodermic needle to pass there through. In some embodiments the head 3 has a width of approximately 6mm, although it will be appreciated that the heads of other embodiments may have differing dimensions.

The arm 2 is shaped for application of the patient abutment surface 4 to a site within a patient's mouth, such as a site on the patient's palatial tissue and/or gum, for example. In one preferred embodiment the elongate dimension of the arm 2 is arcuate. More particularly, the arm 2 has two bends 10 and 11, which together give rise to a total angular divergence of approximately 80°. This arrangement is generally suited to a usage context in which the user of the device 1 stands upright and the patient reclines such that the patient's upper body and head are inclined backwards. However, it will be appreciated that other embodiments may be manufactured with alternative angular divergences that may be better suited to differing relative relationships between the user of the device 1 and the patient. A handle 12 is disposed at a proximal end of the arm 2.

An example of a method of usage of the preferred embodiment in a dental context is set out below; however it will be appreciated that the invention may be utilized in other contexts. The dentist commences the method by abutting the patient abutment surface 4 on the head 3 of the device 1 against the patient at a site of a proposed injection, such as the patient's palatial tissue or gum. The dentist then applies pressure to the handle 12, which is communicated along the arm 2, to the patient abutment surface 4 and ultimately onto the site of the proposed injection. Next the dentist views the patient's palatial tissue or gum through the

substantially transparent head 3. The pressure applied to the site will typically cause blanching of the palatial tissue or gum, which temporarily anesthetizes the site. A typical amount of force that is required to be exerted by the dentist to induce blanching is equivalent to approximately 200 to 500 grams. The degree of anesthetisation may be visually ascertained by the dentist based upon the extent to which the colour of the tissue at the site changes. Sufficient blanching (and therefore anesthetisation) is typically achieved when the colour of the tissue at the site changes from the initial shade of pink to a lighter pinky- white shade.

The provision of a transparent head 3 on the device 1 allows for easy and accurate visual confirmation of the degree of blanching of the tissue upon which the patient abutment surface 4 is exerting pressure. This is especially so as compared to the opaque heads on the devices disclosed in the U.S. prior art patent specifications mentioned above.

Once sufficient blanching (and therefore anesthetisation) of the site has been visually confirmed through the transparent head 3 , the dentist inserts a hypodermic needle through the aperture 6 and injects the hypodermic needle into the patient. With the use of the present invention, the piercing of the hypodermic needle into the patient's tissue is typically much less painful than it would have been without any anesthetisation. Hence, use of the preferred embodiment as an alternative to the use of topical anesthetics typically allows the patient to avoid the potentially unpleasant after-effects that may be associated with such anesthetics. Additionally, use of the preferred embodiment has the potential to reduce the dentist's costs for maintaining an inventory of topical anesthetics.

The insertion of the hypodermic needle into the patient may be achieved by holding the proposed injection site still, and displacing the hypodermic needle tip towards the site. The initial insertion of the hypodermic needle into the patient's blanched tissue is shallow in comparison to the depth of insertion that is ultimately required. Whilst at the shallow insertion depth a small amount of anaesthetic is delivered through the hypodermic needle. The pressure being exerted through the device is then released, which is likely to result in further insertion of the needle at which point the needle is likely to have penetrated a significant proportion of the depth required to deliver the remainder of the dose of anaesthetic. Once the small amount of anaesthetic has taken effect, the needle is fully inserted and the remaining dose of anaesthetic is delivered.

In an alternative insertion methodology the hypodermic needle may be held still with the needle tip immediately adjacent the proposed injection site, at which point the pressure being exerted through the device is relieved. This causes displacement of the proposed injection site towards the needle tip, which results in insertion of the hypodermic needle into the patient. Additionally, some combination of these two approaches may be utilised.

Whilst the hypodermic needle is injected into the site, the dentist removes the anesthetic device 1 by moving the device so as to thread the exposed portion of the injected hypodermic needle through the slot 9. Once the needle has exited from the aperture 6 via the slot 9 in this manner, the dentist completes the injection in the usual fashion.

An embodiment of the invention is disposable and is intended for only a single use. An alternative embodiment is reusable and in accordance with standard steralisation protocols it should be sterilised between usages, for example in an autoclave or the like.

The illustrated embodiments are all one-piece devices and are therefore advantageously resistant to breakage. However, in another embodiment (not illustrated) the head is detachable from the handle at a point approximately half way along the arm. This allows the handle (which is unlikely to be contaminated in typical usage) to be reused, whereas the head and the distal end of the arm (which are contaminated in typical usage) may be disposed of and replaced afresh for each new usage.

The second embodiment as illustrated in Figs. 4 and 5 is shaped for the administration of injections into a patient's inferior alveolar block. The handle 20, arm 21 and head 22 are rectilinearly aligned, with the patient abutment surface 23 being disposed substantially at right angles to the elongate dimension of the arm 21 and handle 20. In this embodiment the aperture is in the form of a U-shaped slot 24.

The third embodiment as illustrated in Figs. 6 and 7 is shaped for the

administration of palatial injections. The arm 30 is arcuate so as to orient the patient abutment surface 31 of the head 32 at an angle relative to the handle 33. This allows the dentist to insert the head 32 and part of the arm 30 into the patient's mouth such that the patient abutment surface 31 can be readily aligned with a proposed injection site on the patient's palate. In this embodiment the aperture is in the form of a U-shaped slot 34

The words "BLOCKBUSTER" and "PALATIZER", as formed in the handles of some of the illustrated embodiments, are examples of potential names under which the device may be marketed. It will be appreciated that such names may be readily omitted, or replaced with other suitable product marketing names, as deemed appropriate.

The fourth embodiment as illustrated in Figs. 8 to 16 is shaped for the administration of both palatial injections and injections into the patient's inferior alveolar block. This advantageously reduces the number of implements with which the dentist must deal. It also simplifies the process of administering injections as it dispenses with a requirement for the dentist to decide whether to use the second or third embodiment for any particular injection.

The arm 40 of the device 39 of the fourth embodiment includes an arcuate portion 41, which bends the arm downwards and to the right relative to the elongate dimension of the handle 42. The rightwardly directed component of the bending of the arm 40 is best shown in the top view of Fig. 10. The extent of the bend to the right, as projected from a top view, is preferably between 5° and 55° and in the fourth

embodiment is approximately 25° to 30°. The downwardly directed component of the bending of the arm 40 is best shown in the side views of Figs. 12 and 13, in which the arm 40 is seen to bend downwardly with reference to the elongate dimension of the handle 42. The extent of the downward bend, as projected from a side view, is preferably between 5° and 55° and in the fourth embodiment is approximately 35° to 40°.

As mentioned in the preceding paragraph, a component of the bending of the arcuate portion 41 is to the right relative to the elongate dimension of the handle 41. This configuration is generally suited to use of the device 39 by a right-handed user.

However, in another embodiment, the rightward component of the bending is replaced by bending to the left, which results in a device that is generally suited for use by left-handed users. That is, for the embodiment that is intended for use by left handed users, the arcuate portion 41 results in a leftwardly directed component of bending, along with a downwardly directed component of bending as described in the preceding paragraph.

The length of the arcuate portion 41 is preferably between 15mm and 45mm and in the fourth embodiment this length is approximately 30mm. It has been appreciated by the inventor that spacing the bend of the arcuate portion 41 along a length of between 15mm and 45mm allows the arcuate portion 41 to take the form of a broad sweeping curve, which may be gently applied to the patient's lip and then used to retract the patient's cheek if this is necessary for access the proposed injection site.

The handle 42 of the fourth embodiment includes ribs 43 so that it may be securely gripped by the user. Additionally, the handle 42 includes upper and lower concave regions 44 and 45, which are shaped so as to comfortably receive the tips of a typical user's thumb or finger. This further facilitates comfortable and secure gripping of the handle 42 by the user.

As can been best seen, for example, in Figs. 10 and 11, the handle 42 is wider than the arm 41 and the head 46. Hence the handle 42 is wide enough to exhibit good ergonomics, whilst the bulk of the arm 41 and head 46 may be minimised. This is desirable because the distal part of the arm 41 and the head 46 are the parts of the device 39 that are inserted into the patient's mouth. Hence, a reduction in the bulk of these parts is likely to help minimise patient discomfort and anxiety about having these parts inserted into their mouth.

The head 46 of the fourth embodiment is best illustrated in Figs. 14 and 16. The slot-shaped aperture 47 tapers from a broader opening 48 on the opposite side of the head to a narrower opening 49 on the patient abutment side of the head. The width of the slot- shaped aperture 47 at the narrow opening is approximately 2mm, whereas the width of the slot-shaped aperture 47at the broader opening is approximately 4mm. This assists the user to thread the needle through the aperture 47.

As shown for example in Figs. 8, 10, 14 and 16, a channel 50 extends longitudinally along a portion of the arm 41 that is proximate to the head 46. This channel 50 is aligned with, and merges into, the slot-shaped aperture 47.

The patient abutment surface 51 includes a plurality of raised formations 52 that are each generally hemispherical and which have a radius of between 0.2mm and 1mm. In the preferred embodiment, the radius of the hemispherical raised formations 52 is approximately 0.5mm. Advantageously, the raised formations 52 assist to minimise slippage of the patient abutment surface 51 relative to the patient's tissue. Additionally, the raised formations 52 have the potential to assist by stretching the patient's tissue to allow for easier penetration of a hypodermic needle.

The alternative head 60 illustrated in Fig. 17 has a longitudinally extending channel 61 which tapers to an end that defines the patient abutment surface 62. A plurality of raised formations 63, in the form of hemispheres, are disposed in a U-shaped pattern along the patient abutment surface 62.

Another alternative head 70 is illustrated in Fig. 18, which is generally similar to that shown in Fig. 16, except with the addition of two curved extensions 71 and 72. The two curved extensions 71 and 72 increase the range of angles at which the head 70 may be applied to the patient. In particular, curved extensions 71 and 72 are suited for application to the steeper portions of a patient's palate.

While a number of preferred embodiments have been described, it will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.