TOOLS OR IMPLANTS USING DENTAL DRILL GUIDES

FIELD OF THE INVENTION The current invention is related to computer guided dental implantology and dental drill guides, and is intended to provide position and/or orientation control during implant drilling or implant placement. The current invention is a device that will generate a signal (audible, perceptible, tangible or visible) to inform the user when the dental tool (implant holder/driver, drill...) reaches a predetermined position and/or orientation planned for dental implant planning software, e.g. in CT-based dental implant planning software.

BACKGROUND TO THE INVENTION

In dental treatment drive apparatuses for rotary tools, known as handpieces, are well known. Dental handpieces come in several shapes and most commonly are either straight or have a swan neck. Figure 1 shows a typical swan-necked dental handpiece, which comprises a handle A, a neck B and a head C in which a rotary tool (e.g. drill, bur, implant driver) is fixed. The handpiece is typically driven by a drive shaft or belt, which extends between the head of the handpiece and a remotely located drive motor. The drive shaft transmits the rotational movement of the motor to the handpiece. Handpieces can alternatively be driven by electric or pneumatic drive motors. Handpieces are used to drive tools during various dentistry operations, such as filling cavities, cleaning and the fitting of dental implants.

The use of implant planning software in combination with surgical drill guides is known technology in dental implantology. For example, 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 scanning to visualize the desired tooth setup. Based on these CT images and by means of dental planning software (e.g. SimPlant, Materialise Dental N.V.) dental implants can be planned taken 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 typically a drill guide (e.g. SurgiGuide, Materialise Dental N.V.) is manufactured. This drill guide fits in the patient's mouth and contains cylindrical tubes which guide the drilling actions in accordance to the treatment plan. More advanced drill guides (e.g. SAFE system, Materialise Dental N.V.) provide additional functionality, guiding the implant placement itself and guaranteeing the axial position (i.e. depth) of the implants relative to the gums. Such depth control is commonly provided by means of a physical stop or by a mark on the dental tool which acts as a visual cue. There are several shortcomings to the available systems for depth control though. These limit the accuracy of the axial position (i.e. the depth) of the implant. When a physical stop is used, the surgeon still needs to pay attention in order to detect the contact between the guide and the tool e.g. drill, implant driver as soon as it occurs. Otherwise there is a risk that the surgeon forces the tool deeper than planned for example due to compression of the soft tissue underneath the drill guide. In case of depth control by marks on the tool, the visibility of the marks can be poor due to for instance water cooling applied during drilling, limited opening of the mouth by the patient, etc. Moreover, detecting the alignment of the mark on the device with the top surface of the guiding tube in the dental drill guide is a subjective action, which can be influenced by the viewing direction of the surgeon.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an alternative device and a method, particularly alternative systems and methods for computer guided dental implantology and dental drill guides. An advantage of the present invention for some embodiments can be that a better depth control is possible and especially that a better position and/or orientation control during implant drilling or implant placement is possible.

The object is achieved by a device according to claim 1 as well as by a method according to claim 9, wherein preferred embodiments of the invention are given by the dependent claims.

The present invention is particularly directed to a device to be used in combination with a dental drill guide, and is intended to generate a signal (audible, perceptible, tangible or visible) to inform the user when the dental tool (e.g. drill) or implant reaches the desired position and/or orientation, i.e. corresponding with the implant position and/or orientation as planned in a dental implant planning software.

The device is particularly characterized in that it has a circuit having two electrical states connected to a signal generator. In a first state, e.g. an open electrical circuit state, no signal is audible, perceptible, tangible or visible that is generated by the signal generator. The circuit enters a second state, e.g. an electrical switch closes, when the desired position and/or orientation of the dental tool or implant (i.e. the one of the planning) is achieved, causing a signal to be produced.

In an embodiment of the present invention a device is provided for use with a dental drill guide and a dental tool or implant, comprising: a signal generator that generates a signal when the dental tool or implant reaches a desired position and/or orientation with respect to the drill guide.

The desired position and/or orientation with respect to the drill guide can correspond with an implant position and/or orientation as planned in a dental implant planning software.

The dental tool can be a drill for example.

The signal generator can be adapted to generate an audible, perceptible, tangible, or visible signal.

Additionally, a circuit can be provided having a first and a second electrical state, wherein the circuit is connected to the signal generator, whereby in the first state, no audible, perceptible, tangible or visible signal is generated by the signal generator, wherein when the desired position and/or orientation of the dental tool or implant is achieved, the circuit is adapted for entering the second state causing an audible, perceptible, tangible or visible signal to be produced by the signal generator.

The first state can be in one option an open electrical circuit state.

A sensor can be provided to sense when the dental tool or implant reaches the desired position and/or orientation with respect to the drill guide.

This sensor can comprise two conductive parts normally in an electrical open circuit condition, wherein the conductive parts are adapted to close when the dental tool or implant reaches the desired position and/or orientation with respect to the drill guide. 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 dental handpiece; Figure 2 shows a preferred embodiment of the invention mounted on the head of a dental handpiece;

Figure 3 shows a preferred embodiment of the invention with a decomposition of the different parts;

Figure 4 shows a sectional view of a preferred embodiment of the invention; Figure 5 shows the moveable part with the ring shaped metal plate;

Figure 6 shows the fixed part with the two half ring shaped metal plates;

Figure 7 shows the clip including the metal plate;

Figure 8 shows a schematic overview of the electrical circuit used by a device according to the present invention.

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 are A and B.

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

According to a preferred embodiment of the invention a device is provided that can be used during implant placement in combination with a dental drill guide and a dental handpiece 1. It is intended to provide depth control during said implant placement by providing e.g. an audible signal to inform the user when the planned implant depth is reached.

Referring the drawings, according to the preferred embodiment the device is an assembly of several components: (i) a signal generator 2 (e.g. LED, buzzer, or vibration motor); (ii) an electrical power transferring means such as a wire mount 3; (iii) a sensor component, such as a circuit gap (CG) component 4 and (iv) a switch 5. The device is connected to a power source 6. This can be a separate power source (e.g. a battery) or can be the same source as the dental handpiece 1. Together the components and the power source form an electrical circuit which can be opened or closed via the switch 5. The design of the components is such that the device can easily be mounted on the dental handpiece 1. According to the embodiment, the sensor component is designed to sense when a certain depth has been reached. In one embodiment the sensor component is exemplified by the CG component 4. CG component 4 has a cylindrical part 7 which fits to the bottom plate 8 of the head C of the dental handpiece 1. This cylindrical part 7 has a central cylindrical hole 9 which lines up with the axis 10 of said head C in order not to hinder the rotary tool 11 (drill, implant driver...) when inserted in the handpiece 1. Extending from the cylindrical part 7 towards the handle A of the handpiece 1 is a retention brace 12 which snaps onto the neck B of the handpiece 1 from the bottom side, directly behind the head C. This retention brace 12 has two arms 13 engaging the neck B of the handpiece 1 on respectively the right and left hand side. The bulk of the CG component 4 is made of an electrically non-conductive material. The component is further characterized in that the bottom 1' of the cylindrical part 7 is equipped with two C-shaped conductive plates 14 (e.g. metallic material), one on either side of the central cylindrical hole 9. Each C- plate 14 is connected to an electrical wire embedded in the CG-component 4. The two wires run up respectively along either arm 13 of the retention brace 12 ending in small metal plates 15 at the outer end of the arms 13. Two similar metal plates 16 are located at the outer ends of the wire mount 3, which also is shaped like a brace with two arms 17 snapping over the neck of the handpiece 1. The wire mount 3 is positioned diametrically opposite to the retention brace 12 of the CG-component 4 so that the respective ends of the arms 13, 17 overlap, forcing the metal plates 15, 16 of both components in contact with one another. The metal plates 16 of the wire mount 3 are connected - via electric wiring 18 - to the poles of the power source 6. The electrical circuit is completed by the signal generator 2 and the switch 5. The former can be integrated for instance in the design of the wire mount 3 as a small LED or can be a separate unit placed in the circuit producing e.g. an auditory signal. Alternatively the signal generator 2 may act as a relay, de-activating the dental handpiece 1 when the circuit is closed i.e. when the desired depth has been reached.

According to the preferred embodiment, the switch 5 snaps onto the head C of the dental handpiece 1, covering the cylindrical part 7 of the CG-component 4. Orientated in the same manner as said cylindrical part 4 and facing the two metal C- shaped plates 14 is the moveable portion 19 of the switch 5. It is thereby also aligned with the axis 10 of the head C of the handpiece 1, necessitating a central opening 20 through which the rotary tool 11 can operate freely. Relative to the portion 21 of the switch 5 attached to the head C of the handpiece 1, the moveable portion 19 can be temporary displaced along the axis of the rotary tool in the direction of the handpiece 1 when loaded (in that direction). A spring or spring-like element/feature 22 (e.g. an annular element or wedge shape) forces the moveable portion 19 back into its original position once the load has been removed. The moveable portion 19 is fitted with a circular metal plate 23 facing the C-shaped plates 14 of the CG-component 4. In use, the moveable portion 19 is loaded when it abuts against the drilling template. As a result, the metal plate 23 of the moveable portion 19 contacts the C-shaped plates 14, which closes the electrical circuit and activates the signal generator 2.

According to a preferred embodiment of the invention the moveable portion 19 of the switch 5 has at the bottom part a means to connect an additional ring shaped part with a certain height in order to adapt the depth position of the tool or implant relative to the dental drill guide.

According to another preferred embodiment of the invention the switch 5 to be mounted on the head C of the dental handpiece 1 can use a screw fitting. Alternatively a bayonet fitting or any other suitable form can be used to mount the switch 5 on the head C of the dental handpiece 1.

According to another preferred embodiment of the invention any connection can be used for the moveable portion 19 of the switch 5 that ensures non-contact with the C-shaped plates ol4 f the CG-component 4 except when the moveable portion 19 of the switch 5 is in contact with the dental drill guide, i.e. at the moment the position and/or orientation of the dental tool as planned in dental implant planning software is reached.

According to another preferred embodiment of the invention the device can be incorporated within or mounted on a manual screw driver that is used in combination with a dental drill guide and is intended to provide depth control during implant placement by providing a signal to inform the user when the implant has reached the planned depth.

According to another preferred embodiment of the invention the device can be designed to provide a signal when the planned rotational position is reached for the implant.

According to yet another preferred embodiment of the invention the device can be designed to provide two particularly different perceptible signals: a first perceptible signal is generated at the moment the planned depth position of the implant is reached and after that a second perceptible signal is generated at the moment the planned rotational position of the implant is reached.

According to another preferred embodiment of the invention the device is used during implant drilling through a dental drill guide by means of a dental handpiece 1 and is intended to provide depth control during said implant drilling action by providing a signal (audible, perceptible, tangible or visible) to inform the user when the drill depth that corresponds with the planned implant depth is reached.

The invention is further directed to a method for indicating the position and/or orientation of a device during the use of said device with a dental drill guide and a dental tool or implant, wherein a signal is generated when the dental tool or implant reaches a desired position and/or orientation with respect to the drill guide. The used device can be designed as previously described. The method can be further designed as previously described with respect to the device according to the invention.

Any of the functionality of devices or methods according to the present invention may be implemented as hardware, computer software, or combinations of both. The signal generator may be implemented with a general purpose processor, an embedded processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination designed to perform the functions described herein. A general purpose processor may be a microprocessor, controller, microcontroller or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.