GB2460643A

GB2460643A - A securing device for dental drill guides

Info

Publication number: GB2460643A
Application number: GB0810023A
Authority: GB
Inventors: Alessio Esposti; Carl Van Lierde
Original assignee: Materialise Dental NV
Current assignee: Materialise Dental NV
Priority date: 2008-06-02
Filing date: 2008-06-02
Publication date: 2009-12-09
Also published as: GB0810023D0

Abstract

A securing device 2 comprises a first or bone component 1 to be anchored into the jaw bone of the patient, and a second or guide component 8 that engages with the first component and locks the drill guide in position. The bone component 1 has a screw thread 3 to anchor it in the jaw bone, an external polygonal connection (4, figure 1) and a flexible ring 6 made from resilient material such as elastomer or rubber. The guide component 8 has a receiving feature 7 to accommodate the polygonal connection (4, figure 1) of the bone component 1, and an annular recess 15 into which the flexible ring 6 can snap. In use, the securing device 2 is screwed into the bone through the cylindrical tube (12, figure 4) of the drill guide (10, figure 4) until a flange 14 on the securing device 2 hits part of the tube indicating that the desired anchorage has been reached.

Description

I

DEVICE FOR STABLE REPEATABLE POSITIONING OF DRILL GUIDES

FIELD OF THE INVENTION

The present invention is related to computer guided dental implantology and dental drill guides and methods.

BACKGROUND TO THE INVENTION

The use of implant planning software in combination with surgical drill guides is known technology in dental implantology. Typically, a CT scan is made of the patient's jaw to visualize the bone in which implants will be placed. In general a scan prosthesis is worn during image acquisition to visualize the desired tooth setup. Based on these CT images and by means of dental planning software (e.g. SimPlant, Materialise Dental N.y.) dental implants can be planned, taking into account aesthetics (i.e. desired tooth setup) and anatomical information (i.e. bone quantity and quality).

To transfer the planning to the patient's mouth a drill guide (e.g. SurgiGuide, Materialise Dental N.y.) can be manufactured and used. This drill guide is used in the mouth where it fits on a predetermined mating region (soft tissue, teeth, bone) and contains cylindrical tubes for guiding the drilling actions at the planned implant positions. More advanced drill guides (e.g. SAFE system, Materialise Dental N.y.) also provide depth control and guide the implant placement itself.

Shortcomings to this system are the lack of dedicated devices for releasably securing * * the drill guide to the jaw of the patient in order to assure immobility of the drill guide during the surgical intervention : *. 25 Patent application WO 03/055407 Al describes the use of 2 or more anchoring **** elements in combination with a soft tissue born template to form holes for implants in bone. The anchoring elements are arranged to extend through side holes or recesses in :. : * . the side walls of the template. The anchoring elements have long and narrow or needle- * shaped designs and are intended to extend horizontally through the gum and into and preferably through substantial components of the whole bone. The purpose of the anchoring elements is to anchore the template to the bone; the resiliency of the gum lying in between should not be allowed to affect the position of the template when the template has been anchored to the bone/jaw bone by means of the anchoring elements.

The patent application (WO 03/055407) does not describe a means for repeatable repositioning of the template. The described anchoring elements are not rigidly connected to the bone and risk of damaging the tissues, both soft and hard, when trying to reposition the template.

SUMMARY OF THE INVENTION

The present invention provides a device that (i) on the one hand allows the dental drill guide to be secured to the patient's jaw and in a predetermined position; and (ii) on the other hand offers an easy way to remove and reintroduce the dental drill guide in said position or to position another dental drill guide in the said position.

Accordingly, the present invention also provides a device intended for releasably securing a dental drill guide to the jaw bone of the patient in a predetermined location allowing the guide to be positioned or re-positioned in a unique, stable and repeatable manner. The present invention provides means to stably and repeatably secure dental drill guides in a predetermined position on the jaw. The device also allows for a sequence of guides related to the same intervention to be secured in an identical position relative to the bone.

The securing device comprises two components: (1) a first component to be anchored into the jaw bone of the patient, and (2) a second component that engages with e.g. *.* snaps onto the first component and locks the drill guide in position. In the remainder of S..

*.. the text the first component will be referred to as the bone component', while the second component will be referred to as the guide component'.

* The bone component is characterized in that when anchored in the bone, all degrees of *. freedom of the component have been removed. *.* *** *

The guide component is characterized in that it physically constrains the movement of the drill guide once engaged with the bone component.

The connection between the bone component and the guide component is characterized in that it is a reversible one.

The present invention also provides methods and apparatus for computer guided dental implantology and dental drill guides.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a preferred embodiment of the bone component of the securing device; Figure 2 shows a preferred embodiment of the guide component of the securing device; Figure 3 shows a mid-section of a preferred embodiment of the securing device (bone component and guide component connected); Figure 4 shows a section of the securing device anchored in the patient's jawbone and securing a dental drill guide. The arrow indicates the insert direction of the guide and parallel to this direction a lateral opening is foreseen in the drill guide to ensure that the bone component of the securing device can pass through.

Figure 5 shows a plug-like design for the bone component of the securing device.

Figure 6 shows an embodiment of the securing device, in which the bone component has a plug-like design.

DEFINITIONS 0'$* * . -*

The bone component is characterized in that when anchored in the bone, all degrees of : 25 freedom of the component have been removed.

The guide component is characterized in that it physically constrains the movement of * the drill guide once engaged with the bone component.

* The connection between the bone component and the guide component is characterized in that it is a reversible one.

DESCRIPTION OF PREFERRED EMBODIMENTS

In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings, which form a part hereof, and within which are shown by way of illustration specific embodiments by which the invention may be practiced.

The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. Those skilled in the art will recognize that other embodiments may be utilized and structural changes may be made without departing from the scope of the invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other orientations than described or illustrated herein.

It is to be noticed that the term "comprising", used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other *:.,.. elements or steps. Thus, the scope of the expression "a device comprising means A and *.,., B" should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device S...

areAandB.

In the following reference to "patient" or "jawbone" should be construed broadly to include not only humans but also animals, especially mammals in need of surgery.

With reference to Figs. 1 to 4, the present invention provides a securing device 2 intended to be used in combination with a dental drill guide 10 as well as the combination itself. According to a particular embodiment of the invention the drill guide 10 has one or more hollow cylindrical tubes 12 through which a drilling action, e.g. a drill, can be guided in case the anchorage site in the bone needs to be prepared prior to instalment of a bone component 1 of the securing device 2. This can for instance be done by means of a dedicated drill with a guidance part adapted to said hollow cylindrical tubes 12 in the drill guide 10. Alternatively standard drills can be used in combination with a key that engages in said tubes 10 and reduces their diameter to the required tolerance to be used with said standard drills.

The securing device 2 comprises a first or bone component I and a second or guide component 8. According to a preferred embodiment of the securing device 2, the bone component 1 has a screw thread 3 to anchor it in the jawbone, an external polygonal 4 at its head, e.g. preferably a hexagonal connection which engages with a corresponding receiving feature 7, e.g. a negative featured element (mirror image element) in the guide component 8, and a flexible ring 6 (e.g. made from a resilient material such as an elastomer or rubber) over which the guide component 8 can press fit or snap. The guide component 8 can include an annular recess 15 into the flexible ring 6 can snap.

The polygonal, e.g. hexagonal connection 4-7 between the bone component 1 and the guide component 8 prevents relative rotation between said components 1, 8, allowing torque loads to be transferred. Thus the securing device 2 can be screwed into the bone directly without the need to disengage the two components 1, 8. The guide component * *. also includes an interlocking feature 13 such as an external or internal polygonal :::::: component, e.g. hexagonal component which allows connection to a torque device for S... . . . screwing the securing device 2 into the bone by application of torque to the guide : .. component 8. S...

S *.*

Also according to the preferred embodiment of the invention, the securing device 2 is : screwed into the bone through the cylindrical tube 12 in the dental drill guide 10 until a * physical stop e.g. a flange 14 on the securing device 2, e.g. a physical stop on the guide component 8 hits a part of said cylindrical tube 12 indicating that the desired anchorage has been reached. Since the securing device 2 is put into the bone through the dedicated cylindrical tubes 12 in the dental drill guide 10, the drill guide 10 cannot be removed as long as the securing devices 2 (and more in particular the guide component 8) is in place.

In order to secure another guide in the same position it must be possible to remove the drill guide 10 or any other guide by only removing the guide component 8 of the securing device 2. This means that the bone component 1 remains anchored in the bone, and the bone component, the guide component 8 and the drill guide 10 are adapted so that only removing the guide component 8 of the securing device 2 allows removal of the guide. This can be realized in different ways, each of which is an embodiment of the present invention. According to a preferred embodiment the guide component 8 of the securing device 2 is sufficiently long to ensure that only it interacts with the cylindrical tubes 12 in the drill guide 10. This means that the bone components 1 are fully submerged relative to said tubes 12 in the drill guide 10.

According to another embodiment, the cylindrical tubes 12 in the drill guide 10 have a lateral opening with a width sufficiently large to ensure that the bone component 1 of the securing device 2 can pass through. These lateral openings for the different securing devices within one drill guide must be foreseen parallel to the insert direction of the drill guide.

Referring to figs 5 and 6, according to another embodiment of the securing device 2, the bone component 1 has a plug-like design, which means that it has parts 20 that expand and move outwardly by use of expansion and optionally locking means such as *:: by inserting a central pin 16, in order to anchor it in the jawbone. The outward motion I...

of the parts 20 can be realized by for instance providing two flexible legs that can bent :.:::. outwardly by moving down a central pin 16 having a conically shaped part 18 that * * 25 mates with a corresponding internal conical part on the bone component 1. This * ** expansion motion is indicated in Fig. 5 -the left hand figure has the central pin 16 only partly inserted, whereas the right hand figure shows the pin 16 completely S..

inserted by which means the legs of the bone component are expanded.

The locking of the central pin I 6 in a certain position can be realized by providing a screw thread 22. Alternatively the central pin 16 and the mating surface of the outwardly moving parts 20 of the bone component 1 can have a rough surface to ensure locking of the central pin 16 by friction. Alternatively a bayonet connection can be provided for locking the central pin (not shown).

Referring to Fig. 6, according to another embodiment the connection between bone component I and guide component 8 can be a screw thread 24. The bone component 1 then has an external screw thread at the top to engage with a receiving feature e.g. a corresponding mirror image feature, i.e. an internal screw thread, featured in the guide component 8.

According to yet another embodiment the connection between bone component and guide component can be a bayonet system (not shown). The bone component can have a radial elevation, protruberance or bump to engage with a receiving feature, i.e. a groove with a tangential slot, featured in the guide component.

According to yet another embodiment the connection between bone component and guide component can be a magnet system (not shown).

According to a preferred embodiment the securing devices 2 have their positional planning included in implant planning software similar to that for dental implants. This is preferred to ensure a correct design of the dental drill guide: the cylindrical tubes for * ** inserting the securing devices are best included in the dental drill guide at the correct position and orientation and if needed the lateral openings must be foreseen for the different securing devices so that removal and repositioning of drill guides is possible. * ** * * S **.*

* . 25 According to another embodiment the positions and orientations of the securing * devices are planned physically on a plaster model onto which the dental implant positions have also been planned. Based on this plaster model one or more dental drill S..

guides can be manufactured using conventional dental lab procedures. The resulting drill guides will include the cylindrical tubes for the securing devices.

Another application of the current invention is to ensure that the drill guide is positioned in the same position as a scan prosthesis. For this purpose the scan prosthesis includes cylindrical tubes placed at candidate sites for placing the securing devices, These cylindrical tubes may be radio-opaque to enhance their visibility in the CT-images of the patient, acquired while wearing the scan prosthesis. By means of dental planning software, it is possible to plan the securing devices according to the position and direction of some or all of the cylindrical tubes included in the scan prosthesis. The dental drill guide will include cylindrical tubes for the planned securing devices, in exactly the same position and with an identical orientation as the corresponding tubes included in the scan prosthesis. During a surgical intervention the scan prosthesis is positioned in the mouth of the patient and secured by means of the current invention. In a next step the guide components of the securing devices are disengaged from the bone components allowing the scan prosthesis to be removed.

Afterwards the drill guide can be positioned and secured by fixing e.g. snapping the guide components back onto the bone components. In this way the drill guide is secured in an identical position as the scan prosthesis and will allow a correct transfer of the implant planning to the mouth of the patient. * ** * a * * S. *... * S S... * *. * S S aS..

S 5.

S * *. * * S *S. *

S 5.

S

Claims

Claims 1. A securing device for use with a guide in dental surgery, comprising: a first component suitable for anchoring into ajaw bone of a patient, and a second component that is adapted to engage and connect to the first component and to reversibly lock the guide in position on the jaw bone.
2. The securing device of claim 1, wherein the second component is secured to the first component by a snap connection, a screw thread, a bayonet fitting or a magnet system.
3. The securing device of claim br 2, wherein the guide is a drill guide.
4. The securing device of any previous claim wherein the guide has a hollow cylindrical tube.
5. The securing device of according to claim 4, wherein the securing device has a stop so that when it is anchored to the bone through the cylindrical tube, the stop hits said cylindrical tube indicating that a desired anchorage has been reached.
6. The securing device of claim 5, wherein the stop is a flange on the second component. * S * S S...
7. The securing device of any previous claim wherein, the second component is : .: adapted so that the guide can be removed after the second component has removed. *. 25

* *
8. The securing device of according to claim 7, wherein the second component is sufficiently long to ensure that only it interacts with the cylindrical tube in the guide. *.S
9. The securing device of according to claim 7, wherein the cylindrical tube in the guide has a lateral opening with a width sufficiently large to ensure that the first component can pass through.
10. The securing device of according to claim 7, wherein the first component has a plug-like design having a part that expands and moves outwardly to lock the first component in the jawbone.
11. The securing device of according to claim 10, further comprising an expansion and locking means outwardly to lock the first component in the jawbone.
12. The securing device of according to claim 11, wherein the expansion and locking means comprises a central pin for insertion in the first component 1 in order to anchor it in the jawbone.
13. The securing device of according to claim 11, wherein the first component has two flexible legs that can be bent outwardly by moving down the central pin having a conically shaped part.
14. The securing device of according to claim 12 or 13, wherein the locking of the central pin in a certain position can be realized by a screw thread.
15. The securing device of according to claim 12, wherein the central pin and the mating surface of the outwardly moving parts of the bone component have a rough surface to ensure locking of the central pin by friction.*
16. The securing device of according to claim 12, wherein a bayonet connection is : .: provided for locking the central pin.S **.S * ** * S S *,S *S *SIS