WO2019180673A1

WO2019180673A1 - Device for assisting in the drilling of a dental implant well

Info

Publication number: WO2019180673A1
Application number: PCT/IB2019/052339
Authority: WO
Inventors: André GENIQUE; Irène GENIQUE
Original assignee: Gencowatt
Priority date: 2018-03-23
Filing date: 2019-03-22
Publication date: 2019-09-26
Also published as: FR3079131A1

Abstract

A device for assisting in the drilling of an implant well using a guide comprising a base (100) provided with a tapped hole (101) coinciding with the position of said well, the device comprising: - a bushing (1) having a threaded outer face (11) capable of cooperating with the tapping of the hole (101) in the base (100) and an inner face (12) delimiting an axial bore (13) intended for a tool to pass through, the proximal end of said bushing carrying a flange (14) comprising at least two radial grooves (15); - a screwing key (2) comprising a cylindrical coupling head (22) comprising at least two tenons (25) capable of being inserted into the grooves (15) of the flange (14) in order to rotate said bushing, and a gripping pin (23) capable of sliding into the bore (13) of said bushing.

Description

DEVICE FOR ASSISTING THE DRILLING OF A WELL FOR A DENTAL IMPLANT

The present invention belongs to the field of dental surgery and relates more specifically to the materials used for implant placement.

It relates to a device for assisting the drilling of a implantation well using a surgical guide, in which a guide sleeve and a screw wrench cooperate to facilitate the work of the practitioner. It also relates to a set of tools comprising a series of sockets and wrenches for a progressive drilling of an implantation well.

A dental implant is intended to provide an anchoring element in the jawbone, on which a prosthesis is fitted to replace one or more damaged teeth between healthy, natural or artificial teeth. Endosseous implants have been developing since the 1970s and 1980s. They are included directly in the heart of the bone tissue, after digging a cavity called "implantation well". A pilot hole is made with a drill of small diameter, then is widened by means of drills of increasing size, until a bore of a suitable diameter for the insertion of the implant is obtained. This operation, performed under local anesthesia, can be performed after incision of the gingiva at the implant site, then separation of the gingival flaps. It can also be performed without a flap, by piercing directly through the gum. Calibrated instrumentation facilitates the placement of implants, either by screwing or by impact, and allows a good fit in the bone.

The implementation of an implant, however, remains a delicate operation. It is first necessary to determine the optimal location of the implant in the maxillary bone, in order to restore the chewing function while providing sufficient mechanical resistance to the efforts, notwithstanding the more or less degraded state of the structure bone of the patient. It is imperative to preserve nearby anatomical structures, such as nerve endings, ligaments and muscles near the implantation area. Special attention should be paid to the dental nerve and sinuses. It is therefore imperative to accurately determine not only the insertion point of the implant, but also its orientation and depth.

Once these dimensional parameters are determined, the installation of the implant must be performed with great precision. In this context, the bore of the implantation well in the maxillary bone is of decisive importance. Indeed, its positioning and orientation will depend on the correct placement of the implant and finally the artificial tooth. It is therefore a delicate operation that requires all the know-how of the surgeon.

To help the implant in the implementation of the implant, various methods have been proposed, the most common are based on the use of a surgical guide. This surgical guide, sometimes called a template, is a counter impression of the intervention zone that includes one or more perforations to the right of the future implant wells. During the operation, the guide is placed on the plantar site by resting on the adjacent teeth of the latter or failing on the gum, and the perforations provide guidance of the drills to practice the bores at the location desired.

The manufacture of surgical guides, initially made by molding, now benefits from advances in computer science and virtual imaging. Thus, computer-assisted implantology has been developed, which makes it possible to manufacture bespoke surgical guides by stereo- lithography corresponding to a pre-established implant planning based on the data obtained by means of a scanner. The data is converted into a virtual drill template and then transferred to a robot for making the actual template corresponding to the topology of the maxillary bone. Virtual imaging is also used to design and produce drill guides for flapless surgery, that is, without incision of the gingiva.

There are different equipments able to plan the implantation in 3D and to realize a template of drilling. It is possible to machine such transparent denture resin templates, for example biocompatible polymer such as PMMA (polymethylmethacrylate), either in a specialized prosthetist or in the dental office if he has suitable equipment.

Whatever the technique chosen, a surgical guide is formed of a rigid base conforming to the forms of the implant site (with or without the gingival tissue) and adjacent teeth so that when it is placed on the alveolar ridge, its position will be unique and stable. The perforation made in the base to guide the drills during the digging of the implant well will also adopt a well-defined position. Most often this perforation will also be useful for guiding the insertion of the implant itself into the well thus prepared. During this operation, several drills of increasing diameter are successively used so as to progressively widen the implantation well without traumatizing the bone tissue. Rather than manufacture several bases, each having a perforation of diameter corresponding to that of a given drill, it is possible to adapt the diameter of the perforation by inserting a guide sleeve. A single base is thus manufactured to which are successively associated bushings of inner diameter corresponding to the diameter of each drill. The bushings are placed and removed one after the other from the perforation of the base.

A difficulty is then to perform these manipulations with dexterity despite the small size of the objects and the inconvenience caused by wearing protective gloves. Another problem is that the bushing must be securely held in place so as not to rotate or disengage while drilling the well, but must then be unscrewed and replaced.

Different types of sockets have been proposed which try to take into account these problems. Interchangeable guide sleeves are known. For example, WO 99/2654 describes a master cylinder fixed in the dedicated hole of the base which successively receives different guide bushes. The bushings are held by clamping a flange contained in the master cylinder, which prevents them from rotating or disengaging during drilling of the well. No particular means is provided for the introduction and removal of sockets.

It has also been proposed in EP 1 596 754 to use interchangeable bushings of different internal diameters for guiding drills. The base comprises a conduit in the form of a chimney in which is fixed a cylindrical metal element by gluing or screwing. The sleeves are then screwed into the cylindrical element. A side slot is provided in this assembly to provide a lateral passage to the drill towards the axis of the conduit. For their installation, the sleeves are threaded on the drill and are screwed automatically when it turns.

These systems have the disadvantage of being long and difficult to implement.

Another guided implant placement technique dispenses with the use of fixed sleeves, using a tool called "spoon insert", consisting of a handle completed by a cylindrical eyelet through which a drill can pass. Once the guide is installed in the mouth of the patient, the practitioner can as desired place the eyelet in the guide hole of the base and remove it, almost instantaneously. During drilling, he must hold the handle in hand so that the spoon is not driven by the rotation of the drill. In doing so, he can not maintain the base. This procedure is inconvenient or impractical when the implantation area is not sufficiently accessible. It is especially a source of inaccuracy in the drilling, because it happens that the drill skids when it encounters a harder structure, which causes a shift of the guide relative to its normal position. The surgeon cluttered by the spoon has no tactile contact with the guide allowing him to feel the drift and correct the drilling.

Thus, none of the current devices is entirely satisfactory. The object of the present invention is to overcome the disadvantages described above by proposing a device contributing to a safe and precise surgical guidance system during an implant placement operation. An object of the invention is more particularly to provide convenient tools and easy to use for the practitioner, regardless of the implantation technique selected. Another objective is to provide a guidance system that can be used for drilling a well using several drills. Yet another object of the invention is to allow the use of drilling guns of different sizes adaptable to a single surgical guide, and whose replacement can be performed quickly, in particular by virtue of a guide element associated with tooling designed for easy handling. An object of the invention is also to propose a set of guide elements and the associated tooling, in the form of a complete work kit, directly usable by the surgeon. It is also sought that the device is robust, easy to maintain and inexpensive.

The present invention meets these objectives. It relates to a device for assisting the drilling of a implantation well for receiving a dental implant in a predetermined position in the maxillary bone, using a surgical guide comprising a base provided with a threaded cylindrical hole whose position is predefined to coincide with the position of said well, the device comprising at least:

- A cylindrical sleeve having an outer face of diameter De provided with a threaded portion adapted to cooperate with the tapping hole of the base; and an inner face delimiting an axial bore of diameter Di intended for the passage of a drilling tool, the proximal end of the sleeve bearing a flange extending overflow in a plane perpendicular to the axis of the bushing, the flange having at least two grooves arranged radially according to a diameter;

a tightening wrench comprising a handle axially extended by i) a cylindrical coupling head comprising at least two tenons capable of being inserted freely in the grooves of the collar to rotate said sleeve and ii) a diameter gripping pin. Dp, able to slid into the bore of said sleeve.

It is specified that the device and the component parts will be described and represented without prejudging the particular orientation that they may adopt during their implementation. The terms "distal" and "proximal" will be used to denote the portion of a piece furthest or closest to the hand of the operator handling the device. The elements having a thread have a given nominal diameter according to the usual conventions (at the bottom of the thread for an internal thread, the tip of the thread for an external thread). The term "maxillary" is the adjective meaning "which refers to the jaw", and it is also a name that will be used interchangeably to designate the upper jaw or the lower jaw, the latter often being called "mandible".

The drilling assistance device according to the invention is intended to be used with a surgical guide previously drawn and produced according to a so-called implant planning process, by one of the techniques which the person skilled in the art has and which he knows. implement, in his office or workshop, with or without the aid of 3D medical imaging equipment and assisted manufacturing, currently commercially available. Such a surgical guide comprises a base conforming to the shape of the gingiva or jawbone and teeth adjacent to the prosthesis, with a hole placed and oriented appropriately to guide the drill during drilling of the well. It can happen that two implants

- or more - must be placed side by side on the jaw, in which case the base may have more than one hole, each corresponding to one of the wells to be dug. Although for the sake of clarity and simplicity, the description that follows presents the invention for the implantation of a single prosthesis, it goes without saying that it extends expressly to a situation where several drilling should be practiced. .

The base can be made from any suitable material, for example a resin or a polymer such as PMMA (polymethylmethacrylate) which has the advantage of being translucent, alone or in mixture, and can incorporate other compounds such as manufacturing aids or the like. According to the invention, the base comprises a tapped hole, cylindrical and through, which is made in the desired location with an optimal orientation in accordance with the planning of the implementation. The threaded hole has a predefined diameter so that a threaded sleeve is inserted by screwing.

The assistance device according to the invention comprises at least one socket and an associated screwdriver whose characteristics allow operation cooperation. The socket and the wrench are made of a strong and inert material, such as a treated stainless steel, preferably food grade or surgical. In general, as will be discussed below, the surgeon uses several pairs each comprising a socket and an associated wrench for complete drilling of a implantation well, each pair having the same operating characteristics in cooperation. Additional tools that may have utility when drilling an implant well will be described later.

The generally cylindrical sleeve, has a threaded outer face adapted to be screwed into the tapping hole of the base for receiving it, the outer diameter De of the sleeve being defined in relation to that of the tapped hole. It also comprises an axial bore for the passage of a drilling tool, whose diameter Di corresponds to the size of the drill. Note that other tools can be guided by a socket according to the invention, such as a drill bit to remove the gingival tissue when operating without flap, depth gauges, and finally the implant itself. These aspects, which will be described later, are an integral part of the invention.

The sleeve carries at its proximal end a circular collar in which are formed grooves for receiving the tenons of the wrench. These grooves, arranged radially according to a diameter of the collar, may be at the preferred number of two, or even three or four, preferably placed equidistant from each other, symmetrically to ensure regular screwing.

The wrench has a coupling head whose function will be to transmit a rotational movement to the sleeve via the tenons it has. The tenons may preferably be two, but also three or four, and in any case equal in number (or possibly less) to the number of grooves of the collar, and placed at the same distance from each other as said grooves, to allow interlocking.

Thus, according to a preferred feature of the device according to the invention, the coupling head of the screwdriver has at its distal end two pins arranged radially along a diameter of said coupling head, which are able to be inserted freely in two diametrically opposite grooves of the flange.

The coupling head is also provided with a gripping pin adapted to slide into the bore of said sleeve. According to a preferred characteristic, the pin is placed in the axial extension of the coupling head between two pins. In this way, when the coupling head and the socket are nested, the tenons are engaged in the grooves while the pin occupies the free space of the bore. It ensures in this way a precise centering of the wrench with respect to the sleeve during insertion thereof into the hole of the base.

The pin also performs a gripping function particularly interesting for handling the sleeve before its introduction into the hole of the base. The key-socket couple, once assembled, remains united thanks to the pin pee in the bore of the socket. It is sufficient if the surgeon holds the key slightly raised or even horizontal, to hold and transport the sleeve to the edge of the hole of the base. The key remaining secured to the sleeve, it remains only to place the latter at the desired location by a simple tilting movement of the wrench, which is then rotated to put the sleeve in rotation. The bushing begins insertion into the base automatically when its net grips the tapping of the base. This sequence, directed from the handle of the wrench, offers the surgeon considerable freedom of maneuver, far superior to that of direct manual insertion of the socket into the hole of the base. It can be performed with ease despite wearing gloves, quickly and without requiring special dexterity of the practitioner.

To make the most of the centering and gripping features shown above, it is recommended that the clearance between the pin and socket be as small as possible. Therefore, in a preferred embodiment of the present invention, the pin has a diameter Dp slightly less than the inner diameter Di of said sleeve, as it allows a fit without floating in the bore of the sleeve. In other words, it means that the clearance between the two parts is minimum but not zero, so that the pin and the bore are associated by sliding adjustment. The common know-how in machining makes it easy to meet these criteria.

To further take advantage of these centering and gripping functions, according to a also preferred embodiment of the present invention, the pin has a length substantially equal to the depth of the socket, such that its distal end is flush with the distal orifice of the bush when the tenons are inserted in the grooves of the collar. Thus the length of the pin (ie the depth of the socket) is maximized.

As already indicated, it is sought to operate safely and without hindrance. By its shape, the coupling head of the wrench meets this requirement. Indeed according to the invention, the cylindrical coupling head preferably has a diameter substantially equal to the diameter of the flange. In this way, it does not create clutter at the periphery of the socket, nor hinders visual access to the implantation site. On the other hand, it constitutes for the tenons the base of support as wide as possible, thus optimizing the torque of rotation.

Also, according to an advantageous embodiment of the invention, the coupling head comprises a double-sided shaped portion converging converging to the two pins. This creates a clearance to better see in all positions the pin and tenons at the distal end of the coupling head, which otherwise would have been masked. It is thus easier to correctly orient the screw wrench relative to the socket when seeking to associate them, and during the screwing to control the advance of the penetration of the socket in the hole of the base.

The operations described above are carried out by maneuvering the device according to the invention using the handle of the wrench. It can come in different shapes and sizes. It may consist of a rod of circular or polygonal section, it may be provided with a conical extension, spherical, or other. Advantageously, the handle of the screwdriver is a smooth rod of circular cross-section having a restricted diameter, smaller than the external diameter De of the bushing, for example between 3 mm and 6 mm, preferably of the order of 3 mm to 4 mm. In this way, the tightening torque that the practitioner can apply to bare hands is limited, which avoids damaging the tapping of the base, or even breaking the base. As for the length of the handle, it must be sufficient for it to be held with two or three fingers, but without creating an inconvenient clutter on the work plan of the surgeon. It may for example be between 25 mm and 35 mm.

Finally, according to another advantageous feature of the present invention, the flange forms a circular shoulder adapted to bear on a flat circular surface formed at the edge of the threaded hole of the base to achieve an axial stop of the sleeve. The sleeve thus overhangs the tapping of the thickness of the flange when the bearing face of the shoulder is in contact with the circular range. This thickness is known and taken into account during the implant planning, the thickness of the base at the threaded hole corresponding to the depth of the sleeve off flange. The surgeon can screw the socket in peace until it reaches the stop.

All of these provisions gives the device according to the invention compactness and ease of handling appreciable. By securing a socket with the base, the practitioner obtains a guide in one piece that can hold with one hand while drilling. He can concentrate totally on the operation, watch the minutia of his gesture and feel a possible displacement of the base requiring an angle correction on his part. This results in a high degree of accuracy and a high level of safety, all for the benefit of patients.

As stated above, during an implant operation, several drills of increasing diameter are successively used so as to progressively widen the implantation well without traumatizing the bone tissue. It is known to use a single base in which will be inserted successively different bushings whose inner diameter corresponds to the diameter of each drill. In this context and according to the invention, the surgeon may wish to use a series of guide bushes and a series of associated wrenches, to proceed to complete drilling of an implantation well. This set forms a complete drilling assistance kit (or surgical kit), comprising several pairs of socket and associated wrench.

Thus, a second object of the present invention relates to an assistance kit for drilling an implantation well intended to receive a dental implant using a surgical guide comprising a base having a threaded cylindrical hole which the position is predefined to coincide with a predetermined position of said well in the maxillary bone, the kit comprising at least:

a set of N cylindrical bushings, each having an outer face of identical diameter With a thread adapted to cooperate with the tapping of the hole of the base; and an inner face delimiting an axial bore of different diameter Di (N) intended for the passage of a drilling tool, the proximal end of each sleeve carrying a flange extending overflow in a plane perpendicular to the axis of the bore. sleeve, the collar having at least two grooves arranged radially in a diameter;

- A set of N wrenches each comprising a shaft axially extended by i) a cylindrical coupling head having at least two pins adapted to be inserted freely in the grooves of the collar of one of said sleeves to rotate it; and ii) a gripping pin of different diameter Dp (N) capable of slidably penetrating into the bore of said bushing of said bushing set.

This drilling assistance kit comprises several pairs of socket and associated wrench, such as the socket and the key belonging to the device described above. In other words, the kit according to the invention comprises a series of N guiding sleeves and N wrenches, intended to be used for drilling an implantation well using a single guide. surgical. The N bushings have an identical outer diameter, so that they can all be installed in the tapped hole of the base. On the other hand, the internal diameter Di of the sockets is different for each of them, in relation to the size of the drills which the surgeon plans to use to prepare the implantary well.

Some elements are dimensionally adapted accordingly. The pins of the N coupling heads have a different diameter Dp (N) corresponding to the bore of each of the N bushings. The collar of the bushings is all the more extensive as the bore is of small diameter, which implies that the length of the radial grooves is also increasing. It is then convenient although optional, that the tenons of the screwing head are extended accordingly.

Other elements can keep their size regardless of the size of the drill to which the sleeve is intended to serve as a guide. Particularly concerned are the section and length of the handle of the wrench, the size of the coupling head, the thickness and depth of the posts in relation to the width and depth of the grooves. he

In a particular embodiment, the drilling assistance kit according to the invention comprises:

i) a set of three to six sockets, and ii) as many screw wrenches each with a pin diameter Dp (N) slightly smaller than the internal diameter Di (N) of one of the sleeves of said set of sockets, so that each pin is adjusted without floating in the bore of the sleeve corresponding thereto. In other words, this means that the clearance (i.e. space) between the two pieces is minimum but not zero, so that the pin and the bore are associated by sliding fit. .

It should be noted that the design of the device according to the invention leads to there being no clearance between the bushings and the hole of the base, which promotes a guide exactly according to the planning. The first drilling, which is decisive for the smooth running of the implant, is made with an unequaled position accuracy, so that the following drills will easily adopt the desired orientation. Under these conditions, it is possible to use one drill less for the drilling of the implantation well compared to the number of drills usually used.

In the kit according to the invention, preferably, the coupling head of each wrench comprises a double-sided converging double-sided portion, the distal end of said portion carrying two tenons arranged radially according to a diameter of the d-head. coupling and a pin diameter Dp (N) placed in the axial extension of the coupling head, between the two pins.

The kit according to the invention may furthermore comprise a screwdriver dedicated to unscrewing a socket after drilling. Such a screwdriver may advantageously comprise a handle extended axially by a beveled rod whose distal end comprises a blade adapted to be inserted into the grooves of a socket, the handle having a diameter greater than the outer diameter of said sockets. Indeed, it is common that during drilling, the sleeve is rotated by the drill and blocked in the hole of the base, so that its withdrawal requires the use of a relatively high torque, and certainly higher that does not allow the wrench whose handle is designed precisely to avoid a too powerful tightening. Thus, to unlock the socket without difficulty, it is possible to use a screwdriver serving as an unscrewing key, whose handle has a large diameter so as to increase the unscrewing torque. The blade of the screwdriver when placed in the grooves, occupies preferably the entire diameter of the flange, so that the torque is maximum.

It will be advantageous to also add to the parts of the kit according to the invention one or more depth gauges. Each gauge comprises a gripping member carrying a pin of defined length. The dimension between the top of the surgical guide (which can be materialized by the range surrounding the tapping of the base) and the top of the already placed implant being known, it is possible to control the depth of insertion of the implant, particularly when the flapless technique is used (in this case indeed, the depth reached is not visible). An accuracy of less than 0.5 mm is thus obtained.

The present invention provides the practitioner who uses it an increased tranquility and working comfort, because it can have more assured and precise gestures, without loss of time. It is guided efficiently, allowing it to focus more on the drilling process, in particular to regulate the speed of the drill thus avoiding the phenomena of stuffing and overheating. Finally, the placement of the implant is better controlled, leading to better osseointegration for the benefit of the patient.

The present invention will be better understood, and details will arise, in the light of the description which will be made of different embodiments, in relation to the accompanying figures, in which:

Fig.1 is an exploded perspective view of a drill guide according to the invention comprising a base and a socket, with a wrench.

Fig. 2a is a longitudinal sectional view of a socket according to the invention.

Fig. 2b is a top view of the same socket.

Figs. 3a and 3b are side and side views of a wrench according to the invention. Fig. 4 is a representation of a set of keys and sockets of a kit according to the invention.

Figs. 5a and 5b are perspective views of a depth gauge according to the invention. Fig. 6 is a front view of a screwdriver according to the invention.

EXAMPLE 1: Assistance device for drilling

FIG. 1 represents a device for assisting the drilling of an implantation well according to the invention, comprising a base 100, a socket 1 and a screwdriver 2. These parts can be made of treated stainless steel, such as a food grade stainless steel or surgical stainless steel. All the dimensions given below are by way of example. They may vary in proportions compatible with the intended use and subject to the limitations inherent in the invention, which will be indicated where appropriate. The general tolerance of workpiece processing (by machining) is +/- 0.1 mm unless otherwise stated.

The base 100 made of PMMA or other suitable material, includes the threaded hole 101 bordered by the circular range 102. Windows 103 are formed at the projecting portions of the supporting teeth, which makes it possible to control the placement of the bases unequivocally. The threaded hole 101 has a diameter which is here 7 mm (M7 not 100). It is desirable to be able to adapt the size of the tapped hole according to the patient's own parameters (the size of the implant to be placed, the space of the available implantation area, the shape and quality of the maxillary bone). As a result, the tapping may be made in different sizes (for example small, medium or large diameter). This example relates to a tapped hole having a large diameter. It will be easily transposed for other dimensions.

The sleeve 1 also shown in Figures 2a, 2b, is cylindrical and has an outer face 11 of diameter De, with a threaded portion adapted to cooperate with the thread of the hole of the base. The diameter De can be classically 7 mm (M7 not 100). The bushing 1 has an inner face 12 delimiting the axial bore 13 of diameter Di intended for the passage of a drill bit. Of course, the value of the diameter Di is a function of the diameter of the wick used, which varies commonly between 2 mm and 5.5 mm (with a tolerance of +0.02 mm to +0.05 mm).

The proximal orifice of the bore 13 comprises the chamfer 17 forming for example on 1 mm an angle of 30 ° with the axis of the sleeve, so as to facilitate the correct introduction of the drill (pre-centering). The proximal end of the sleeve carries the collar 14 which extends overflow perpendicularly to the axis of the sleeve and has the grooves 15, here two in number, arranged radially in a diameter of the flange 14. The flange 14 , wider than the threaded portion of the sleeve, forms the circular shoulder 16 which will be supported on a flat circular range 102 formed at the edge of the threaded hole 101 of the base 100 to make an axial stop of the sleeve 1 and stop its operation. advanced without the surgeon having to exercise particular control. The sleeve 1 may have a total height of 6 mm, the flange 14 occupying 1 mm, the threaded portion extending over 4 mm and being separated from the flange 14 by the clearance groove 18.

The tightening key 2 shown in FIGS. 3a and 3b comprises the handle 21 extended axially by the cylindrical coupling head 22 which comprises, on the one hand, two diametrically opposed tenons 25 and, on the other hand, the gripping pin 23.

The tenons 25 can be inserted freely into the two grooves 15 of the flange 14, in order to rotate the sleeve 1 when the surgeon applies a rotational movement to the tightening key 2 via the handle 21. sliding fit with minimal clearance between pins 25 and grooves 15. Grooves 15, carefully deburred, may have a width of 1 mm (tolerance +0.1 to +0.2) and pins 1 mm (tolerance 0 to -0.05). The depth of the grooves 15 as the length of the tenons 25 may be equal to 1 mm. The grooves 15 and tenons 25 and have an optimal cohesion which gives great precision to the surgeon's gesture.

The gripping pin 23 is placed in the axial extension of the coupling head 22, between the two tenons 25, so that it is placed in the bore 13 of the sleeve 1 when the tenons 25 are inserted into the pins. grooves 15. It has a diameter Dp slightly smaller than the internal diameter Di of the sleeve 1, as it achieves a sliding fit without floating in the bore 13. To do this, the tolerances are from +0.02 to +0 , 05 for the diameter of the bore 13, and 0 to -0.05 for the diameter 23 of the pin. The nominal diameter Dp of the pin 23 is a function of the value of the internal diameter Di of the sleeve 1, itself imposed by the diameter of the drill used. Furthermore, the pin 23 has a length substantially equal to the depth of the sleeve 1, for example 5 mm from the end of the tenons 25. In this way its distal end 24 is flush with the distal orifice of the sleeve 1 when the tenons 25 are inserted into the grooves 15 of the collar 14.

The coupling head 22 of generally cylindrical shape has a diameter substantially equal to the diameter De of the flange 14, for example 8 mm, for a total length of the order of 12 mm. It comprises at its distal end, a bit portion ace shaped double bevel 26 converging to the two tenons 25, at an angle of 45 ° to the axis of the key 2. The handle 21 is a smooth section rod circular right whose diameter may be 3.5 mm for example, for a length of 30 mm. Key 2 can be manufactured in one piece, or in two parts, the pin 23 can be machined separately and then inserted into force (clamping 0.01 to 0.02 mm) in a bore of 8 mm to 10 mm deep made at 1 distal end of the coupling head 22, between the studs 25.

In accordance with the rules of the art, different chamfers are provided to soften the sharp angles of the parts described above. It is not necessary to describe them all.

EXAMPLE 2: Drilling Assistance Kit

In Figure 4 is shown a portion of the elements of a tool kit for drilling a well implementation. It comprises a series of three wrenches 201, 202, 203 and a series of three sockets 101, 102 and 103. The wrenches and sockets are paired pairwise to work together in three pairs N1, N2 and N3. Each of these pairs corresponds to a device such as that presented in Example 1, to which reference will be made. They differ from each other by the characteristics outlined below.

The bushes 101, 102 and 103 have an identical outer diameter, for example 7 mm (M7 steps of 100), each being able to cooperate with the tapping of a single base 100. On the other hand, the axial bore 13 is different for each, since each bushing is intended to guide a drill bit of a different given diameter. The internal diameter Di (N) of the sleeves 101, 102 and 103 may be between 2 mm and 5.5 mm. The flange 14 extending overflow at the proximal end of each bushing 101, 102 and 103 is even narrower than the bore 13 is important. The same is true of the length of the grooves 15 formed in the collar.

The wrenches 201, 202, 203 are distinguished from each other by two characteristics. On the one hand, the pin 23 will have a larger diameter as the axial bore 13 will be wide, to maintain a sliding fit regardless of the dimensions of the tools. Due to minimal play between the pieces, the surgeon's gesture can have excellent precision. On the other hand and corollary manner, the tenons 25, which preferably have the same length as the grooves 15, will shorten with the increase of the axial bore 13.

For an implant 5 mm in diameter, it is generally used according to the hand techniques current lifting five successive drills of increasing diameter, for example 2 mm, 3.2 mm, 3.7 mm, 4.2 mm and 4.7 mm. Thanks to the tooling according to the present invention, it will be possible to perform the drilling optimally with only four drills, having a diameter of respectively 2 mm, 3.2 mm, 4.2 mm and 4.7 mm. The resulting time saving can then be used by the practitioner to concentrate on other actions and to relieve more quickly the patient undergoing the procedure.

A kit according to the present example may thus include four drills and four sockets of corresponding dimensions. Complementary tools may also be implemented with the help of these sockets, as illustrated below.

EXAMPLE 3: Complementary tools

A: Screwdriver

The kit according to the invention may comprise a screwdriver (or key unscrewing) dedicated to unscrewing the bushes 1, 101, 102, 103, after drilling, although it may have other uses.

As shown in Figure 6, the screwdriver 3 is generally cylindrical. It comprises the handle 31 extended axially by the beveled rod 32 whose distal end comprises the blade 33. This blade 33 can be inserted into the grooves 15 of a sleeve 1, to apply a torque for the unscrewing of the sleeve 1 , 101, 102, 103. The blade 33 has a width ideally identical to the diameter of the flange 14, 8 mm in the kit given in Example 2. The handle 31 has meanwhile a diameter greater than the outer diameter of the sleeve 1, for example 15 mm. The total length of the screwdriver 3, for example 30 mm to 60 mm, must remain compatible with its use and not clutter the worktop.

B: Depth Gauge

The kit according to the invention may comprise depth gauges 4 (FIGS 5a and 5b), each consisting of a grip button 41 carrying a pin 42 of different definite length. The button 41 has a flat circular distal face 44 which can bear on the flange 14 when the pin 41 is slid through the bore 13 of the sleeve 1. Such a support will be achieved if the implant is deeper than the freelancer 42. The distal edge of the pin 42 is advantageously fluted. The length L of a peg is defined from the distance separating the top of the base 100 and the implant, known during the planning of the implantation. The top of the base can conveniently be marked by the position of the range 102 surrounding the tapped hole 101 of the base. Each gauge 4 is marked with the corresponding dimension (taking into account the thickness of the flange 14), for example on the upper face 43 of the button 41, easily visible.

EXAMPLE 4: Assistance Kit

In the case of a flap-free operation, a first socket guides a bit for removal of a gingival tissue core. Several other bushings are intended to guide the drills. A socket allows depth control using a depth gauge. Finally, a socket is dedicated to guiding the insertion of the implant. Some sockets are used several times (see following examples).

The kit ideally comprises two series of gauges 4. A given series of gauges 4 is assigned to a particular key-socket couple, whose pin 23 has the diameter Dp (N). The diameter of the rod 42 of the gauges 4 is then equal to the diameter Dp (N) of the pin. In the series concerned, the rods have different lengths L, one slightly lower and the other slightly greater than the desired depth (see following example).

EXAMPLE 5: Installation of an implant with a diameter of 3.5 mm

The surgeon can practice according to the following steps, using a base and the tool according to the invention.

- Removal of a gingival tissue core: 3.5 mm diameter drill bit used with a 4.2 mm diameter socket + screwdriver (case of flapless technique)

- Drilling a pilot hole: 2 mm drill bit used with a 2 mm diameter socket + wrench

- Axis control

- Second drilling: 3.2 mm drill bit used with a 3.2 mm diameter socket + screwdriver

- Third drill: 3.35 mm drill bit used with 3.35 mm diameter socket + wrench

- Implant placement (3.5 mm diameter): 3.7 mm diameter socket + screwdriver - Depth control: series of gauges 3.7 mm in diameter, for example for a theoretical length of 11.2 mm, an 11 mm gauge and a gauge of 11.5 mm, used with a socket of 3, 7 mm diameter + screw wrench

- Installation of a cover screw, chosen with adequate convergence.

- At each step: unscrewing screwdriver

EXAMPLE 6: Installation of an implant with a diameter of 5 mm

- Removal of a carrot of gingival tissue: 4 mm diameter drill bit used with a 4.7 mm diameter socket + screwdriver (case of flapless technique)

- Axis control

- Third drilling: 4.2 mm drill bit used with 4.2 mm diameter socket + wrench

- Fourth drilling: 4.7 mm drill bit used with a 4.7 mm diameter socket + wrench

- Implant placement (5 mm diameter): 5.2 mm diameter socket + screwdriver

- Depth control: series of 4.7 mm diameter gauges, used with a 4.7 mm diameter socket + wrench

- Installation of a cover screw, chosen with adequate convergence.

- At each step: unscrewing screwdriver

Claims

1 - Assistance device for drilling a implantation well intended to receive a dental implant in a predetermined position in the maxillary bone, with the aid of a surgical guide comprising a base (100) provided with a threaded cylindrical hole (101) whose position is predefined to coincide with the position of said well, the device being characterized in that it comprises at least:

- A cylindrical sleeve (1) having an outer face (11) of diameter With a threaded portion adapted to cooperate with the tapping hole (101) of the base (100); and an inner face (12) delimiting an axial bore (13) of diameter Di intended for the passage of a drilling tool, the proximal end of said bushing carrying a flange (14) extending overflow in a plane perpendicular to the axis of the sleeve (1), said flange comprising at least two grooves (15) arranged radially in a diameter;

- A wrench (2) comprising a handle (21) extended axially by i) a coupling head (22) cylindrical having at least two pins (25) adapted to be inserted freely in the grooves (15) of the collar (14) for rotating said sleeve and ii) a pin (23) for gripping diameter Dp, able to slide into the bore (13) of said sleeve.

2 Device according to claim 1, characterized in that the coupling head (22) of the wrench (2) has at its distal end two lugs (25) arranged radially along a diameter of said coupling head, which are able to be inserted freely in two diametrically opposite grooves (15) of the flange (14).

3. Device according to claim 1 or 2, characterized in that the pin (23) is placed in the axial extension of the coupling head (22) between two pins (25).

4 Device according to one of the preceding claims, characterized in that the pin (23) has a diameter Dp slightly smaller than the internal diameter Di of the sleeve (1), and such that it allows adjustment without floating in the bore (13) of said socket.

5 Device according to one of the preceding claims, characterized in that the counter

(23) has a length substantially equal to the depth of the sleeve (1), such that its distal end (24) is flush with the distal orifice of said socket when the tenons (25) are inserted into the grooves (15) of the flange (14). 6. Device according to one of the preceding claims, characterized in that the coupling head (22) has a diameter substantially equal to the diameter De of the flange (14).

7. Device according to claim 2, characterized in that the coupling head (2) comprises a double bevel shaped portion biface (26) converging to said two pins (25).

8. Device according to one of the preceding claims, characterized in that the handle (21) of the wrench (2) is a smooth rod of circular cross section having a diameter of between 3 mm and 6 mm.

9. Device according to one of the preceding claims, characterized in that the flange (14) forms a circular shoulder (16) adapted to bear on a flat circular surface (102) formed at the edge of the threaded hole (101) of the base (100) for producing an axial stop of the sleeve (1).

10. An assistance kit (100) for drilling an implantation well for receiving a dental implant using a surgical guide comprising a base (100) having a threaded cylindrical hole (101) whose position is predefined to coincide with a predetermined position of said well in the maxillary bone, the kit comprising several pairs of socket and associated wrench belonging to an assistance device according to one of claims 1 to 9, and being characterized in that it comprises at least:

a set of N cylindrical sockets (1), each having an outer face (11) of identical diameter With a thread capable of cooperating with the tapping of the hole (101) of said base; and an inner face (12) delimiting an axial bore (13) of different diameter Di (N) for the passage of a drill bit, the proximal end of each sleeve (1) carrying a collar (14) extending overflow in a plane perpendicular to the axis of said bushing, said collar comprising at least two grooves (15) arranged radially in a diameter;

- A set of N wrenches (2) each comprising a handle (21) axially extended by i) a cylindrical coupling head (22) having at least two pins (25) adapted to be inserted freely in the grooves (15). ) of the flange (14) of one of said sleeves to rotate it; and ii) a peg (23) with a different diameter Dp (N) suitable for slidingly penetrate into the bore (13) of said bushing of said bushing set.

11. Kit support (100) to the drilling according to claim 10, characterized in gu ^r \\ comprises i) a set of three to six sleeves (1), and ii) as many tongs (2) each provided with a pin (23) of diameter Dp (N) slightly smaller than the internal diameter Di (N) of one of the sockets (1) of said set of sockets, so that each pin (23) is fitted without floating in the bore ( 13) of the corresponding sleeve.

12 Assistance kit (100) for drilling according to one of claims 10 or 1 1, characterized in that the coupling head (22) of each wrench (2) comprises a double-sided shaped portion ( 26), whose distal end carries two pins (25) and a pin (23) of diameter Dp (N) placed in the axial extension of the coupling head (22), between said two pins. 13-. Drill assistance kit (100) according to one of claims 10 to 12, characterized in that it further comprises a screwdriver (3) comprising a handle (31) axially extended by a beveled rod (32) whose distal end comprises a blade (33) adapted to be inserted into the grooves (15) of a sleeve (1), said handle having a diameter greater than the outer diameter of said sleeves.