GB2357432A

GB2357432A - Tooth extractor

Info

Publication number: GB2357432A
Application number: GB9930044A
Authority: GB
Inventors: Rajesh Khanna
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-12-20
Filing date: 1999-12-20
Publication date: 2001-06-27
Also published as: GB9930044D0; AU2204101A; WO2001045584A1

Abstract

This invention relates to the field of dentistry, and in particular to the extraction of teeth or roots of teeth. According to one aspect of the present invention there is provided an extraction device for removing a tooth, or root of a tooth, embedded in a patient's jaw, which device comprises tooth engaging means (11), abutment means (41) to be placed around or adjacent to the tooth to be extracted and means (21, 32) for displacing said engaging means relative to the abutment means in a direction which draws the tooth from its bed. The engagement means may be a screw cutting thread and the abutment means may be a collar for the tooth. The displacement means may be a rack and pinion mechanism. Also claimed is an extraction kit comprising a range of replacement screw threaded cutting bits and replacement collars.

Description

2357432 Tooth Extractor

This invention relates to the field of dentistry, and in particular to the extraction of teeth or roots of teeth. 5

A tooth consists of a crown covered by very hard translucent enamel and a root covered by bone-like cement. The enamel covers an internal structure comprising substantially dentine. The dentine contains an interior pulp cavity which typically extends into core of the root to form a pulp canal. The human jaw is formed with a plurality of sockets which accommodate rows of teeth. A periodontal ligament separates each root from the jaw socket. Fleshy gums surround the teeth and cover the neighbouring areas of jaw.

Tooth decay causes localised destruction of the enamel and rapid erosion of the internal dentine. In severe cases the pulp cavity is opened to reveal painful nerves in the interior of the tooth. Treatment of decayed teeth may involve filling, to replace decayed and eroded tooth material. In certain cases, for example where infection has set in, the tooth must be removed. Similarly orthodontal treatment of the arrangement and appearance of teeth may require removal of selected teeth. Recent 2 developments in prosthetic teeth involve removal of individual teeth and immediate replacement by individual prosthetic teeth.

Removal of a tooth is a time consuming and difficult procedure. A typical method involve the use of forceps to grip the crown of the tooth and pull the tooth f rom the jaw. This is an awkward technique which is may be uncomfortable for the patient whose tooth is being extracted, and difficult for the dentist who must exert relatively high levels of force to pull the tooth from its bed in the jaw. Frequently, when the tooth is decayed or otherwise damaged, the crown may be pulled off by the forceps, leaving the root behind and embedded in the jaw.

Removal of this remaining fragment of the tooth is very difficult because it is almost impossible to get any purchase on the embedded root. Because of this elevators may have to be wedged between the root and socket. The elevators are rocked to lever against the root and cause it to lift from the socket. Occasionally it is necessary to operate on the jaw to remove bone f rom around the socket in order to access, a nd permit clamping of the obscured root. This can be damaging to the jaw, and renders the adjacent teeth vulnerable. The above described complications increase the time taken for 3 extraction and greatly increases the pain, especially post-operatively, due to the extensive tissue damage.

It is an object of the present invention to provide an improved apparatus and method of removing teeth from the jaw of an person or animal According to one aspect of the present invention there is provided an extraction device for removing a tooth, or root of a tooth, embedded in a patient's jaw, which device comprises tooth engaging means, abutment means to be placed around or adjacent to the tooth to be extracted and means for displacing said engaging means relative to the abutment means in a direction which draws the tooth from its bed.

The present invention has many advantages, but in particular it provides a controlled means of extraction from the surrounding tissue. Because the abutment means may be placed on the surrounding teeth, jaw or gums, the drawing movement is braced and stabilised.

Preferably the engaging means comprises a screw cutting thread capable of being driven into the interior of a tooth or root of a tooth. An advantage of this is that 4 the engaging means may engage with the relatively soft interior of the tooth, providing good mechanical keying and a sound mechanical cannectionf whatever the state of the crown. In addition, because the interior of the tooth is engaged, it is not necessary to remove the surrounding tissue from around the root. Thus the trauma suffered by the patient may be reduced.

In a preferred embodiment of the present invention the abutment means comprises a collar configured to fit around the tooth to be extracted, and abut the gums and jaw adjacent the tooth to be removed. The collar may be removably attached to the device, thereby permitting attachment of alternative collars.

is The collars may be rendered removable by the provision of screw threaded attachment means operative between the device and an end of each collar. A plurality of replacement collars may be provided, each configured for different tooth shapes and sizes.

In one embodiment, the means for displacing the engaging means comprises a rack and pinion mechanism. Preferably a rack is f ixed for travel with the engaging means and a pinion is rotatably attached to the abutment means. The pinion may then be rotated to move the engaging means in a tooth-drawing direction, with the f orce reaction being directed in an opposite direction to brace the abutment means in position against the jaw. There may be two pinions, for example on one either side of a cylindrical rack. In one embodiment each pinion is provided with a lever which permits manual rotation of the pinion through an arc corresponding to drawing out of the engaged tooth. The pinion lever may be provided with a handle portion. 10 In another aspect of the present invention the pinion forms a component of a gear train, which gear train provides a mechanical advantage.

The displacing means may comprise a powered mechanical mechanism. This is preferably a mechanism compatible with the electrically driven, hydraulically driven or compressed air driven power systems currently used for dental tools.

In yet another aspect of the invention, the cutting screw is adapted to be replaceable. The screw may be provided on a bit, which bit may engage with the device by means of a bayonet mount or chuck engagement arrangement of a type common in the field of dental or other drilling

6 tools. The replacement screws may be of varying thread pitch, wavelength, amplitude and length. In this way the optimum engagement with a particular tooth can be made.

In one aspect of the present invention the screw thread is rotated by a handle to effect engagement with a tooth. In another aspect of the present invention the screw thread is rotated by a powered mechanical drive means. Conveniently a dental power tool connection may be made to take advantage of known power drives, such as electrical, compressed air or hydraulic.

According to yet another aspect of the present invention, there is provided a method of extracting a tooth or root of a tooth from an animal or person comprising: providing an extraction device as hereinbefore described, causing the engagement means to engage with the tooth or root, causing the abutment means to abut a portion of the gum or jaw or teeth surrounding the tooth or root to be removed, and operating the displacing means whereby the engaging means and engaged tooth or root are displaced relative to the abutment means, which abutment means is braced in position by the reaction of the abutment means against the displacing force, thereby to draw the tooth or root from its bed.

7 According to yet another aspect of the present invention there is provided a dental surgeon's tooth extraction kit comprising a tooth extraction device as hereinbefore described wherein the engaging means comprises a removable screw threaded cutting bit and the abutment means comprises a removable collar to be located around a tooth, and wherein the kit further comprises a plurality of replacement screw threaded cutting bits in a range of different configurations and a plurality of 10 replacement collars in range of configurations.

Following is a description by way of example only and with reference to the drawings of a method of putting the present invention into effect.

is In the drawings:- Figure 1 is side elevation, partially in section, of an extraction device according to the present invention.

Figure 2 is a top elevation of the handle shown in f igure Figure 3 is a side elevation of an extraction device 25 according to the present invention.

8 Figure 4 shows the different possible sizes and shapes of the collar shown in f igure 3.

Figure 5 shows a gear train located between the rack and 5 pinion of an extraction device according to an alternative embodiment of the present invention.

In figure 1 a screw head 11 comprises a bit formed with a sharp cutting thread 12 sufficient for cutting into a tooth or root of a tooth. The screw head is selected from a plurality of screw heads of dif f ering sizes to suit the dimension of the tooth or root being removed. The plurality of screw heads typically all have a length of less than 25 millimetres and a diameter of between 2 and 4 millimetres at the top and tapering to a point at the bottom. The plurality of screw heads may be made f rom stainless steel or tungsten- carbide. It may be necessary to specify a tool grade steel, or another high performance material, in order to maintain cutting performance and confer sufficient strength to permit tooth extraction.

The screw head is attached at a base end thereof to a generally cylindrical shaft 13. The attachment is by means of a bayonet mount 14 (detail not shown) of 9 conventional construction. The bayonet mount permits screw head detachment and replacement with another screw head of a dif f erent conf iguration.

The shaf t is formed from stainless steel and is formed with a plurality of axially spaced annular rings 2 1. An extension 22 of the shaft is provided at a lower end thereof with a rectilinear handle 23. The handle is fixed to the shaft by suitable means, for example a grub screw engagement. An upper end of the shaft extension is formed with a flat 24. This permits drivable engagement with a mechanical power drive (not illustrated) of a type conventional in the art. The handle 23 is preferably removed when the power drive is attached. The handle is formed from stainless steel and is about 40 millimetres in length. The handle has a rectangular groove 27 intruding from each end face of the handle. The overall length of the shaft and extension is about 100 millimetres.

The shaft is accommodated in a sleeve 30 formed from stainless steel. The shaft is not attached to the sleeve and thus is free to rotate within the sleeve. The sleeve has a generally cylindrical configuration. A mid region of the sleeve is formed with two radially extending arms 31. An end region of each arm is provided with a rotatably mounted pinion gear 32. Each pinion is provided with an elongate lever portion 33 which extends radially from the pinion. When the handles are perpendicularly, that is fully extended, the total width is about 80 millimetres or less. Elongate slots (not shown) are formed longitudinally of the sleeve, on opposite sides thereof and adjacent each arm. The pinion teeth are entered into the slots to engage with the annular rings on the shaft 21.

A lower end region of the sleeve is formed with an internal threaded portion 40. A generally tubular abutment collar 41 is provided at an upper end thereof with a screw threaded external portion 42. This engages with the threaded portion 40 of the sleeve, as shown in figure 1. The collar accommodates the screw threaded cutting bit 11.

The collar may be replaced by a range of differently sized collars 45, examples of which are shown in figure 4. One of the collars 46 has a generally oval section and flares outwardly at a base end 47 thereof. Another of the collars tapers 48 inwardly at a base end 49 thereof. The cross section of the lower end regions of the collars is 11 not limited to round or oval. The configurations available are dictated by the likely tooth shapes encountered. The primary concern is. that the collar should surround the tooth to be extracted and provide sufficient clearance for the tooth to be raised within the collar.

In an alternative embodiment a gear train 50 is inserted between the pinion and the rack. The incorporation of a gear train advantageously provides a mechanical advantage and thus less downward pressure is required to raise the shaft.

In use, the dentist f irst has to attach the bit to the tooth. In the case of decayed teeth or damaged teeth direct access to the pulp interior of the tooth may be possible. In cases where the tooth is structurally sound and the crown is intact it may be necessary to provide an initial access bore by drilling into the interior of the tooth. This initial boring may be performed by conventional dentists drilling equipment.

The screw threaded cutting bit is then placed against a top end surface of the tooth. The bit is manually turned by the handle 23. It cuts into the interior of the tooth, 12 preferably into at least the upper end region of a root canal of the tooth. As the cutting continues the collar is drawn down around the tooth and against the gums. Eventually the collar will abut the bone of the jaw surrounding the tooth to provide a solid bracing of the collar.

The tooth removal process involves depressing the lever arms 33. This rocks the pinions which act upon the annular rings to lift the shaft within the sleeve. The cutting bit is lifted along with the shaft. The collar directs a reaction to the lifting forces onto the jaw bone surrounding the tooth, and maintains stable bracing of the device. The tooth is gradually and controllably drawn from its socket.

The present invention allows the controlled and safe removal of teeth from the jaw. A particular advantage is the ability to remove root portions of damaged teeth, even in the absence of a crown portion. This is done without the removal of surrounding bone, and therefore results in considerably less damage to the patient. For the dentist, the device is considerably easier and less time consuming to use.

Claims

13 Claims

1. An extraction device for removing a tooth, or root of a tooth, embedded in a patient's jaw, which device comprises tooth engaging means, abutment means to be placed around or adjacent to the tooth to be extracted and means for displacing said engaging means relative to the abutment means in a direction which draws the tooth from its bed.

2. An extraction device as claimed in claim 1 wherein the abutment means comprises a collar configured to fit around the tooth to be extracted, and abut the gums and jaw adjacent the tooth to be removed.

is

3. An extraction device as claimed in claim 2 wherein the collar is removably attached to the device, thereby permitting attachment of alternative collars.

4. An extraction device as claimed in claim 3 wherein the collars are rendered removable by the provision of screw threaded attachment means operative between the device and an end of each collar.

5. An extraction device as claimed in claim 3 or claim 14 4 wherein a plurality of replacement collars are provided, each configured for different tooth shapes and sizes.

6. An extraction device as claimed in any preceding claim wherein the means for displacing the engaging means comprises a rack and pinion mechanism.

7. An extraction device as claimed in claim 6 wherein the rack is fixed for travel with the engaging means and a pinion is rotatably mounted and fixed relative to the abutment means.

8. An extraction device as claimed in claim 7 wherein is the pinion is rotated to move the engaging means in a tooth drawing direction, with the force reaction being directed in an opposite direction to brace the abutment means in position.

9. An extraction device as claimed in any of claims 6 to 8 wherein there are two pinions, f or example on one either side of a cylindrical rack.

10. An extraction device as claimed in any of claims 6 to 9 wherein a pinion is provided with a lever which is permits manual rotation of the pinion through an arc corresponding to drawing out of the engaged tooth.

11. An extraction device as claimed in claim 10 wherein 5 the pinion lever is provided with a handle portion.

12. An extraction device as claimed in any of claims 6 to 11 wherein a pinion f orms a component of a gear train, which gear train provides a mechanical advantage.

13. An extraction device as claimed in any preceding claim wherein the displacing means comprises a powered mechanical mechanism, operative between the engagement means and the abutment means.

14. An extraction device as claimed in claim 13 wherein the mechanical mechanism is adapted to be powered by an electrically driven, hydraulically driven or compressed air driven power system.

15. An extraction device as claimed in any preceding claim wherein the engaging means comprises a screw cutting thread capable of being driven into the tooth or root of a tooth.

is

16 16. An extraction device as claimed in claim 15 wherein the cutting screw is adapted to be replaceable.

17. An extraction device as claimed in claim 15 or 16 wherein the screw is provided on a bit, which bit may engage with the device by means of a bayonet mount or drill chuck engagement.

18. An extraction device as claimed in any of claims 15 to 17 wherein replacement screws of varying in one or more of thread pitch, wavelength, amplitude and length are provided such that in use the optimum engagement with a particular tooth can be made.

19. An extraction device as claimed in any of claims 15 to 18 wherein the screw thread is adapted to be manually rotated by means of a handle thereby to effect engagement with a tooth.

20. An extraction device as claimed in any of claims 15 to 18 wherein the screw thread is rotated by a powered mechanical drive means.

21. An extraction device as claimed in claim 20 wherein a dental power tool connection is provided whereby 17 advantage may be taken of a power drive, such as electrical, compressed air or hydraulic power drives.

22. A method of extracting a tooth or root of a tooth from an animal or person comprising: providing an extraction device as hereinbefore described, causing the engagement means to engage with the tooth or root, causing the abutment means to abut a portion of the gum or jaw or teeth surrounding the tooth or root to be removed, and operating the displacing means whereby the engaging means and engaged tooth or root are displaced relative to the abutment means, which abutment means is braced in position by the reaction of the abutment means against the displacing force, thereby to draw the tooth or root f rom its bed.

23. A dental surgeon's tooth extraction kit comprising a tooth extraction device as hereinbefore described wherein the engaging means comprises a removable screw threaded cutting bit and the abutment means comprises a removable collar to be located around a tooth, and wherein the kit further comprises a plurality of replacement screw threaded cutting bits in a range of different configurations and a plurality of replacement collars in range of configurations.