GB2143437A - Oral retractor for animals - Google Patents

Abstract

An oral retractor to hold open an animal's jaws for veterinary or dental surgery or investigation comprises a pair of spring biased side members each folded to a generally V-shaped configuration together with lower and upper cross members mounted between corresponding end portions of the side members to form a substantially rectangular frame. <IMAGE>

Description

SPECIFICATION Veterinary oral retractors This invention relates to oral retractor devices for use by veterinarians and dentists for retracting or holding open an animal's jaws.

A prior art device, known also as a dental gag, comprises a generally vertical post and two slideable arms mounted at opposite post ends and held apart by a compression spring encircling the post. In one form, the free arm ends have holes for receiving opposed anterior cuspids in the animal's jaws for anchoring of the gag. A less popular modification has rubber shod arms for mounting between the animal's jaws. Both forms are relatively complex and expensive to manufacture. In addition, both forms suffer from the disadvantage that the gag when used is positioned outside of the oral cavity on one side only of the animal's mouth, and since the animal often struggles to dislodge the gag, the resultant severe pressure can cause jaw dislocation and impair occlusion. In addition, the jaw-anchored modification has a tendency to shift or slip during use.The more popular form using tooth anchorage avoids the problem at the expense of introducing additional disadvantages as a result of relying on the anterior cuspids for its total support. Often the use of such a device causes breakage of the anchoring teeth at the cuspid or at the bone itself. Moreover, older animals may have weak, semi-mobile cuspids, or broken cuspids or worn cuspids. The teeth of young animals which are not fully developed would not be long enough to hold such a device. Such gags are not useful in such cases. Hence, use is limited only to those animals that have firm, strong cuspid teeth. However, as previously indicated, even in the latter cases, the one-sided support coupled with any animal's attempts to dislodge the gag, can still result in injury to the animal's jaw or teeth.

A principal object of the invention is an improved oral retractor which overcomes the above-mentioned disadvantages.

A further object of the invention is an oral retractor device that can be quickly, easily and comfortably inserted into an animals oral cavity to effectively and safely retract and expose all of the oral cavity to treatment by a veterinary or a dentist.

Still another object of the invention is a novel retractor which is of simple construction, light in weight, inexpensive to manufacture, yet effective and reliable in operation throughout a long useful life.

In accordance with the invention, the foregoing objects are achieved with a novel oral retractor constituted, simply, of two side spring-biased members whose corresponding ends are interconnected by lower and upper cross members to form a generally rectangular frame configuration folded at the spring sides. In a preferred embodiment, the cross members have increased width and are constituted of generally tubular sections mounted between the side member ends.

The invention will now be described in greater detail with reference to a preferred exemplary embodiment taken in conjunction with the annexed drawings, wherein: Figures 1, 2 and 3 are side, front and back views, respectively, of one form of oral retractor in accordance with the invention; Figure 4 is a side view illustrating use of the retractor of Figures 1-3.

As is well known to those versed in the veterinary-dental arts, oral retraction is necessary and desirable in most oral animal procedures including surgical procedures and dental procedure.

For example, it is now common practice in the small animal practice to clean animal teeth by hand scaling and ultrasonic scaling. Thus a need exists for a safe, effective oral retractor to provide greater access by practitioners into the oral cavity. Our novel retractor meets this need. A preferred embodiment is illustrated in Figures 1 to 3 at 5. The retractor 5, shown in its open or unbiased condition, comprises two spring steel side members 10, 11 which may be identical or mirror images of one another.Each spring steel member 10, 11 comprises a single length of spring wire coiled at its centre to form a spring loop 1 2. The wire extends from the loop as shown to form two main arms, a lower main arm 13 and an upper main arm 13', near the ends of which they underto a first angled bend at 14 towards one another to form first proximate end portions 15 lying generally in the plane of the coil 12 (also the plane of Figure 1), and then a second angled bend at 1 6 generally transverse or perpendicular to form second distal end portions 1 7 extending toward the opposite wire spring. The two main arms 13, 13' form a generally V-shaped configuration having an included acute angle indicated by 1 8 of approximately 70 degrees.The corresponding second end portions 1 7 of the lower 13 and upper 13' main arms are interconnected by tubular cross members designated, respectively 20 and 20'. The tubular cross members 20, 20' may be constituted of metal, plastic or hard rubber which are clamped or adhesively bonded to their respective end portion 1 7 as shown in Figure 2. The tubular members 20, 20' can have axial holes that extend partially as shown in Figure 2, normally extend completely through the tubular members. If of metal, it is preferred to sheath or cover the tubular members 20, 20' with a softer plastic or rubber cover. While shown round in cross-section, the tubular members 20, 20' can also have other configurations, such as square or hexagonal.

As will be observed from Figure 2, the upper cross member 20' is slightly shorter in length than the lower cross member 20, obtained by a slight bending of the upper arm portions 13' out of the plane of the wire loops.

The configuration shown in Figures 1-3 is with the device in its unbiased condition. If pressure is applied manually across the lower and upper arm members, vertically in Figure 1, tending to close the structure resulting in a reduced included angle 18 at the V apices, this action would bias the spring loops 12 which would resist such action. If the pressure were removed, the spring action would restore the device to its unbiased condition as illustrated. In the latter condition, a certain spacing indicated by reference numeral 1 9 would exist between the lower and upper cross members 20, 20. When the frame 5 is compressed, that spacing 19 would be reduced.

Figure 4 illustrates how the oral retractor 5 of the invention would be used. As will be noted, a dog's head 30 is shown with lower jaw 31 and upperjaw 32. Typically, the lower jaw 31 is wider (viewed from the front) than the upper jaw 32, which is the reason for the different lengths of the cross members 20, 20'. The practitioner would open the jaws of the animal 30, compress the frame springs 12 to reduce the spacing 19 between the lower and upper jaw members 20, 20' and then insert the device into the open jaws of the animal so as to position the lower cross member 20 inside the animal's lower jaw 31 just inside the lower teeth arch, and the upper cross member 20' inside the animal's upper jaw 32 just inside of the upper jaw teeth arch, with the spring end 12 extending inward toward the throat.Then the device would be released and the biased spring arms 13, 13' would attempt to restore the device to its unbiased condition by applying opening pressure against the animal's lower and upper jaws. The dimensions and angles are chosen such that, when positioned as shown inside the animal's oral cavity between its jaws, the springs would not fully open because of the limited size of the oral cavity and thus would be lodged firmly between the animal's jaws with the V-apices of the device extending inside the oral cavity and remote from the front teeth as shown in Figure 4. The softer sheath covering the cross tubular members 20, 20' would prevent injury to the animal's jaws or teeth. Any attempt by the animal to close its jaws, indicated by the arrow 25 in Figure 4 would be resisted by the spring coils 12.

As mentioned previously, other shapes for the tubular members 20, 20' will be suitable, and in some instances advantageous. For example, a non-circular shape, such as a flattened oval, elliptical, rectangular or hexagonal, could provide greater retention of the device within the animal's jaws by the flatter sides lodging against the inner surfaces of the upper and lower rows of teeth.

While the configuration illustrated of the two bent wire side members 1 0, 11 interconnected by the cross tubular members 20, 20' is preferred, other modifications should also be workable. For example, spring-like resilient plastics are known which can be substituted for the metal wires 10, 11. Alternatively, the coils 1 2 and the adjacent parts of the arms 13, 13' can be made of spring steel wire, and the remaining sections of the side members (remote parts 13, 13', 1 5 and 17) composed of other materials such as plastic connected to the spring wire arms.As still a further alternative, the entire frame 5 can be made up of metal but coated with an insulating plastic for added safety when an electrosurgery or electrocautery procedure is used. when metal is used for the various parts, it has the advantage that it can be made of stainless steel and autoclaved and sterilised when desired for long term use.

The device is suitable for use with different animals, including cats, dogs, pigs, sheep, cows and horses. The dimensions of course would have to be varied to fit the different sizes of the animal's oral cavities. There follows below a table of dimensions in mm for three sizes of the retractor suitable for use with small medium and large sized dogs, respectively, the numbers in parenthesis being reference numerals indicating the relevant dimension in the drawings.

Small Medium Large (50) 1.96 2.39 3.18 (51) 88.9 101.6 139.7 (52) 19.1 19.1 19.1 (53) 12.3 12.3 12.3 (54) 88.9 108.0 171.5 (55) 44.5 57.2 69.9 (56) 25.4 38.1 50.8 (57) 44.5 69.9 82.6 (58) 38.1 49.2 61.9 (59) 4.76 4.76 6.35 While an angle 18 of approximately 70 degrees is preferred for dogs, it is not critical and it can usually vary for different animals but will usually be an acute angle in the range 50-85 degrees.

While the preferred embodiment uses metal tubular members 20, 20' permanently secured to the side members 10, 11, they can, if desired be replaceably secured, as by a friction fit, to allow replacement of members 20, 20' if they become damaged or worn. In addition, they need not be composed entirely of metal, but of any reasonably stiff structural element, such as wood or plastic, or of stiff tough rawhide commonly used as teeth exercise for dogs. Also, the members 20, 20' can be scented or flavoured with an appropriate scent or flavour for greater acceptability by the animal, such as meat for dogs, catnip for cats. In addition, as mentioned, the members 20, 20' can be provided with a soft or semi-soft covering of plastic or rawhide to prevent injury, also suitably flavoured or scented if desired. Further, while stainless steel for the side members 10, 11 is preferred, other known spring metals can be substituted, such as titanium or aluminium alloys.

Still further, the device of the invention can be used at home as well as professionally.

As will be evident from the foregoing, the retractor of the invention is not only of simple construction, of light weight and inexpensive to manufacture, but in use offers the advantages of being quickly, easily, securely and comfortably inserted in the animal's oral cavity. In addition, it will safely hold the animal's jaws open, without undue pressure or uneven pressure distribution being imposed on the teeth or jaws, and readily exposes all of the oral cavity for treatment. Since the lodging inside the oral cavity is distributed over the full length of the cross tubular members, no high pressure concentrations occur and thus less tendency to crack or injur teeth or jaws, with the result that it can be safely used in older animals.

While our invention has been described in connection with specific embodiments thereof, those skilled in the art will recognise that various modifications are possible within the principles enunciated herein and thus the present invention is not to be limited to the specific embodiments disclosed.

Claims (11)

1. An oral retractor for use in holding open the jaws of an animal characterised by pair of spring biased side members each folded to form a generally V-shaped configuration defining an included angle in its unbiased condition, and lower and upper cross members mounted between corresponding end portions of the side members to form therewith a generally rectangular frame wherein the spacing between the lower and upper members when the side members are in their unbiased condition can be reduced by applying pressure to the lower and upper members tending to reduce the included angle by biasing the side members.

2. An oral retractor as claimed in claim 1 characterised by the side members are generally parallel to one another and the lower and upper cross members are generally parallel to one another.

3. An oral retractor as claimed in claim 2 characterised by each side member comprises a single spring metal wire bent approximately at its centre to form a spring loop and outwardly extending arms to form the V and having angled end portions.

4. An oral retractor as claimed in claim 3 characterised by each angled end portion of the V arms comprises a first proximal portion bent inward and generally in the plane of the V and a second distal portion bent inwardly towards the other side member and generally transverse to the plane of the V.

5. An oral retractor as claimed in claim 4 characterised by the upper and lower cross members comprise tubular members of increased width mounted across corresponding second distal portions of the side members.

6. An oral retractor as claimed in claim 2 characterised by the upper cross member is shorter than the lower cross member and is dimensioned to fit inside the upper jaw of the animal and the longer lower cross member is dimensioned to fit inside the lower jaw of the animal with the V apices of the side members extending inside the oral cavity and between the animal's jaws.

7. An oral retractor as claimed in claim 6 characterised by at least the tubular cross members are provided with a covering of nonmetallic material.

8. An oral retractor as claimed in claim 7 characterised by the covering is softer than the cross members.

9. An oral retractor as claimed in claim 1 characterised by the cross members are replaceably mounted on the side members.

10. An oral retractor as claimed in claim 1 characterised by the cross members are flavoured or scented.

11. An oral retractor substantially as herein described with reference to and as shown in the accompanying drawings.