HK1109048B - Cutting insert for a vibrating dental instrument - Google Patents

Abstract

The invention relates to a vibrating insert (100) comprising a body (110) having a first end (111) designed for being mechanically coupled in a rigid manner to a surgical handpiece (100) that generates vibrations, and having a second end to which a tool holder (112) is fixed that serves to reproduce the vibrations transmitted by the handpiece. The insert also comprises a tool (120) having a working area (121). According to the invention, this tool (120) is mounted in a manner that enables it to freely rotate with the tool holder (112) whereby enabling the tool to automatically orientate itself in order to stay in contact with the tooth and to present the working area over the entire periphery of the tooth with a single insert. The tool preferably comprises two working areas for improving the holding and guiding of the tool on and to the surface of the tooth to be processed.

Description

Cutting insert for vibrating dental instruments

Technical Field

The present invention relates to dental treatment instruments, and more particularly to vibrating instruments, such as scaling instruments, which include instruments that vibrate at audible or ultrasonic frequencies.

Background

An instrument of the type shown in fig. 1A consists essentially of a handpiece 1 comprising a transducer rigidly mechanically connected to a vibrating instrument called a "tip" 10, which is connected to a vibration generator (not shown). Examples of such tips are described in particular in documents US 6312256 and US 4283175.

The tip may have a variety of shapes depending on its intended use (e.g., descaling: removal of solid deposits, polishing: removal of biofilm, grinding: cavitation or repair preparation) and is a replaceable component.

As shown in fig. 1A, the prior art device comprises a body 11, most commonly of metal, one end of which is rigidly assembled to the transducer of the handpiece 1, the other end of the body 11 extending a tool holder (tool holder) which itself extends from a tool 12 fixed to the body. The tool includes a working region, which may be a sharp edge, a smooth edge or a smooth surface, or a diamond-bearing surface, that can be associated with an abrasive suspension (abrasive subsension). The vibrations generated by the transducer are thus transmitted directly to the working area of the tool.

In order to be able to use the tip on all sides of the tooth, the tip is often designed in three shapes: straight, left-handed and right-handed. During a dental grinding operation, in particular for the purpose of peripheral preparation, the operator must use at least two different modes of the tip: right-handed and left-handed.

This is because, due to the restriction of the patient's mouth opening and the lateral closing of the mouth by the cheeks, as defined by line O in fig. 1A, the tip must be angled and its movement around the tooth to be ground is relatively limited. The double-ended arrow C shown in fig. 1A depicts the maximum travel the operator can move the handpiece 1.

Thus, during subsequent operations involving the entire periphery of the tooth, for example in order to prepare the peripheral grinding of the tooth 20 for use, for example, for fitting a prosthesis (crown), the operator must use at least two points: one tip is adapted to position the working area of the tool on the front of the tooth and the other tip is adapted to position the working area on the back of the tooth.

More precisely, as shown in fig. 1B and 1C, the operator uses a first tip 10a comprising a curved body 11a, with the working area 13a of the tool facing inwards, so as to be able to grind the rear part of the tooth 20 with the working area 13a of the tool 12a, and a second tip 10B with a curved body 11B, with the working area 13B of the tool 12B facing outwards, so as to make it possible to grind the front part of the tooth.

In order to avoid having to use two tips during peripheral grinding of the teeth, another solution consists in using a single tip with an axisymmetric working area. An example of such a tip is depicted in fig. 2A and 2B, which show two tips 30a and 30B of different sizes, with respective bodies 31a, 31B extending from a tool holder, and respective tools 32A, 32B having respective axisymmetric working zones 33a, 33B that include a diamond-bearing surface over their entire circumference. It is thus possible for the operator to perform peripheral grinding of the tooth 40 with the same tip.

Although this solution allows peripheral grinding without requiring too large an angular movement stroke of the axis of the body of the tip, it has significant drawbacks. This is because, as shown in fig. 2A and 2B, the tool must have a diameter equal to twice the grinding depth, i.e. up to twice the width of the asymmetrical tool, due to the axially symmetric nature of the working area 32A of the tip, and since the latter must have a rotary shape whose cross-section reproduces the desired preparation shape. In this case, either the tool is not available or there is a great risk of attacking parts of the adjacent teeth 41, 42.

One solution may consist in using a tool 23b of reduced diameter. However, the use of such a tip significantly reduces the depth of grinding that can be performed without completely eliminating the risk of damaging the teeth 41 and 42.

Moreover, regardless of the type of tip used, the vibrations result in vibrations in the end region of the working area due to the presence of axial vibrations. These vibrations may cause poor surface conditions of the treated part.

Thus, the use of vibrating tips, whether asymmetric or axisymmetric, especially for peripheral milling operations, has proven to be relatively difficult and provides little advantage in the field over conventional rotary instrument technology.

Disclosure of Invention

The object of the present invention is to propose a design that enables the working area of the tool to be positioned on all peripheral parts of the tooth, crown or root with the same tip, without the risk of damaging adjacent teeth. This object is achieved by a vibrating tip comprising, according to the invention, a tool mounted so as to be able to rotate freely with the end of a tool holder fixed to the body of the tip to which the body of the tip is connected and reproduce the vibrations transmitted by the handpiece.

Thus, the tip according to the invention has a design that enables the tool to be detached from the rest of the body of the tip connected to the handpiece. Since it is free to rotate about the body of the tip, the tool automatically adjusts itself (i.e., rotates) to maintain contact with the tooth, making it possible to position the working area with a single tip over the entire periphery of the tooth.

The tool further comprises two working areas for guiding and holding the tool in contact with the surface of the tooth to be treated. This is because the fact of having two working zones on the tool that can rotate freely enables working on the surface of the tooth with two different support points. Thus, during the movement of the tool over the tooth, the two working areas help the tool to remain in very stable contact with the tooth, since the pressure exerted by the operator on the handpiece is distributed between the two working areas, which results in the tool being held firmly on the tooth even during the movement.

The other parts of the tool are preferably smooth to protect adjacent teeth. The working area may be treated or covered with a material of abrasive material such as diamond. The working area preferably has a shape corresponding to the pre-treatment (grinding, descaling, polishing, etc.).

According to one embodiment of the invention, the tool comprises at least one guide pin in the lower part for limiting the penetration depth of the tool. The guide pin may be formed by a member fixed to the tool or by the end of the tool holder passing through the bottom of the cavity of the tool.

The tool is preferably a removable and interchangeable element comprising a bore forming a cavity for mating with the tool holder, a mechanism attached to the tool holder to enable the tool to rotate freely, one or more working portions which may be sharp edges, smooth surfaces, abrasive surfaces, or mechanically, chemically or thermally treated surfaces.

According to one embodiment of the invention, the means for attaching the tool to the tool holder comprises at least one rod, the end of which cooperates with retaining means made on the tool holder.

The tools may be interchangeable so that the same tip body may be used with different tools.

According to one aspect of the invention, a tool includes a cavity forming a housing for a tool holder. Particles made of flexible material may be arranged in the bottom of the cavity in order to dampen the shock or any impact effect between the end of the tool holder and the tool.

It is another object of the present invention to provide an acoustically vibrating dental treatment instrument comprising at least one surgical handpiece connected to a vibration generator, characterized in that it further comprises at least one tip as previously described.

Drawings

Further characteristics and advantages of the invention will emerge from the following description of particular embodiments of the invention, given by way of non-limiting example with reference to the accompanying drawings, in which:

FIG. 1A is a perspective view showing the movement limitation of an asymmetric tip of the prior art;

figure 1B shows a partial cross-section of at least two different tips that must be used during peripheral grinding of a tooth according to the prior art;

FIG. 1C is a top view of FIG. 1B showing that at least two different tips have to be used during peripheral grinding of a tooth according to the prior art;

figure 2A is a partial cross-sectional view of a grinding operation performed with an axisymmetric tip of the prior art;

figure 2B is a top view of a grinding operation performed with an axisymmetric tip according to the prior art;

FIG. 3 is a perspective view of a tip according to an embodiment of the invention;

FIG. 4 is a partial sectional view showing the tip of FIG. 3 during a grinding operation;

FIG. 5 is a top view showing the different positions the working head of the tip of FIG. 3 assumes during the grinding operation;

FIGS. 6A, 6B and 6C are a perspective view and two cross-sectional views, respectively, of a tip for scaling or polishing a tooth or root surface, according to one embodiment of the invention, FIG. 6C is a top view showing the tooth and tool along section VIC of FIG. 6A;

figures 7A, 7B and 7C are respectively a perspective view and two cross-sectional views of a tip according to another embodiment of the invention;

figures 8A, 8B and 8C are respectively a perspective view and two cross-sectional views of a tip according to another embodiment of the invention.

Detailed Description

Fig. 3 shows a tip 100 according to a first embodiment of the present invention. The tip 100 comprises a body 110 made of a single piece, for example made of metal, having a first end 111 adapted to be fixed to the handpiece 101. In a known manner, the handpiece 101 is a sonic or ultrasonic vibration generator, which may include a transducer (not shown) formed, for example, of piezoelectric material and rigidly mechanically coupled to the tip to transmit the vibration waves thereto. The second end of the body 110 forms a tool holder 112 for reproducing vibrations transmitted through the handpiece. The tool holder 112 is rigidly assembled with the body of the tip 110 (nut and bolt system, welding or simple extension of the tip).

In accordance with the present invention, a tool 120 is disposed on the tool holder 112. The tool 120 includes a cavity 122 that serves as a housing for the end of the tool holder 112. The tool 120 is connected to the tool holder 112 by means of a stem 123 fixed to a ring 124 which, by bearing on the shoulder 113, is able to limit the translational movement of the tool on the tool holder. In the embodiment shown in fig. 3, the tool holder 112 comprises a second shoulder 114 which forms with the shoulder 113 an annular groove 115 in which a ring 124 is received. However, the gripping of the ring 124 may be achieved by a simple collar disposed on the tool holder 112 at the shoulder 113 to prevent the tool from coming off the end of the tool holder, the bottom of the cavity 122 then acting as a limit stop to limit the lifting of the tool on the tool holder.

Other forms of mechanism for attaching a tool to the tool holder are contemplated, as will be described later. In general, any type of mechanism capable of mounting a tool to rotate freely with a tool holder is possible with the present invention.

Depending on the circumstances, the rotation of the tool about the tool holder may be complete or limited to an angular range determined by the positioning of the limit stops.

In accordance with the present invention, a tool holder 112, generally corresponding to the tip 100 of the tool, is received in a cavity 122 of the tool 120. By this mounting, vibrations reproduced at the end of the tool holder 112 are transmitted to the tool 120, in particular to the working area 121 of the tool. Thus, unlike prior art tips in which the working portion is fully secured to the body of the tip, the tip according to the present invention includes a rotationally movable element that is driven by the vibration of the end of the tool holder 112.

Optionally, particles 126 made of a flexible material (e.g., a soft metal or elastomer) may be disposed in the bottom of the cavity 122 to dampen shock or impact motion between the end of the tool holder 112 and the tool 120.

The tool 120 includes a working area 121 for contact with the walls of the teeth to be abraded or treated (scaling, polishing, etc.). To this end, the working area 121 may be coated with a friction material such as diamond, or the working area may be smooth and capable of being used in conjunction with a solution containing abrasive particles. The shape of the tool 120, and in particular the shape of the working area 121, depends on the grinding profile or the treatment to be performed on the tooth.

The other portion of the tool 120 is an untreated smooth section, which is preferably of a small size to facilitate penetration of the working head and avoid contact with adjacent teeth. Indeed, as shown in fig. 4, it can be noted that the largest part of the tool 120 is the part comprising the working area 121 that is kept in contact with the tooth wall of the tooth to be ground. The remainder of the tool 120, including the post 123 and retaining ring 124, is of a smaller size, which reduces the risk of contact with the adjacent tooth 140.

The body of the tip and the tool are preferably made of materials that are resilient and capable of withstanding vibrational motion in a frequency range that may range from subsonic to supersonic. Such a material may be, for example, a metal.

By virtue of the free rotation of the tool 120 about the tool holder 112, the tooth can be ground using a point pattern over the entire circumference of the tooth. This is illustrated in fig. 5, which shows different positions of the tool 120 during peripheral grinding of the tooth 130. It should further be noted that the free rotation of the tool 120 can keep the body 110 of the tip almost always in the same direction, and therefore the handpiece to which it is attached. This allows the operator to select the working position no longer according to the part of the tooth to be ground, but according to his most comfortable working position, for example depending on whether he is right-handed or left-handed.

According to one embodiment of the invention, the tool may be provided with guide pins 125 at its end. As shown in fig. 4, the guide pins 125 prevent the working area 121 from contacting the gums 160. Thus, since the operator no longer has to continuously control the distance between the end of the tool and the gum, his grinding operation becomes less difficult. Furthermore, as shown in fig. 4, the guide pins also enable the gums 160 to be moved away.

Furthermore, the position of the pins 125 on the tool and their height make it possible to control the penetration depth of the working area into the tooth. More precisely, the guide pins 125 make it possible to control the lateral penetration of the tool into the tooth. This is because, as shown in fig. 4, it is no longer possible to remove material once the guide pin 125 rests on the surface 130b of the tooth 130, and therefore the guide pin 125 acts as a limit stop that allows the operator to grind the tooth without having to take special care of the depth of penetration of the tool, since this was previously limited by the guide pin.

In a variant embodiment, the guide pin also includes a working area to provide descaling and cleaning of the surface of the tooth 130b and adjustment of the angle 130 c.

The tool may also have two working areas, a diamond area for grinding of the teeth and a smooth area for polishing of the tooth wall.

The shape of the guide pins may vary. It is preferably cylindrical to facilitate guidance of the tool over the tooth. Also, two guide pins may be arranged on the tool, depending on the circumstances.

Fig. 6A-6C illustrate another embodiment of the present invention. The tip 400 shown in fig. 6A and 6B is used for polishing/descaling. To this end, it comprises a tool 420 having two working areas 421a and 421b forming a rounded edge which may be treated and shaped according to the tooth anatomy. Fig. 6C highlights the advantages of two working areas guiding and holding the tool in contact with the surface of the tooth 430 to be treated. This is because, according to the invention, the tool is mounted so as to be able to rotate freely with the tool holder. Holding the tool on the surface of the tooth proves difficult for using a tool comprising a single working area when the operator exerts pressure on the handpiece in order to keep the tool in contact with the tooth having a curved surface (sliding of the tool on the tooth causes undesired rotation of the tool itself and loss of contact of the working area with the tooth surface). With two working areas spaced as shown in fig. 6C, the pressure is distributed over the two working areas (double contact points), enabling good stability of the tool support on the teeth even if the tool is moved. Thus ensuring good contact of the working area with the teeth.

Fig. 7A-7C depict another embodiment of a tip according to the present invention. The tip 200 shown in these figures differs from the tip of figures 3 and 4 firstly in that a portion of the end of the tool holder secured to the body of the tip 210 passes completely through the tool. More specifically, as shown in fig. 7A-7C, the tool holder 212 supports a tool 220 in which a cavity 222 is provided to receive an end of the tool holder 212. The end has a terminal portion 225 that passes through the bottom of the cavity 222. In this embodiment, a portion of the terminal portion 225 beyond the tool 220 forms a guide pin 226 that can limit the penetration depth in the same manner as described above with respect to the guide pin 125 of the tool 120.

Other significant differences from the embodiment shown in fig. 3 and 4 relate to the mechanism for attaching the tool to the tool holder. This is because, in the embodiment described here, the tool 220 is connected to two rods 223a, 223b, each comprising at their ends a lug 224a, 224b, which fits into a recess 215 provided on the tool holder 212. The rods 223a and 223b are resiliently deformable to facilitate the installation and/or removal of a tool from the tool holder.

As with the tips described above, the tool 220 includes a working area 221 that may be coated with an abrasive material such as diamond, or otherwise smoothed or treated and possibly used in conjunction with a solution containing abrasive particles. The tool may obviously also have many other types of shapes that the person skilled in the art will easily conceive of according to the grinding profile they want to obtain.

Fig. 8A-8C show another variant embodiment of the tip according to the invention. The tip shown in these figures differs from the tip of fig. 7A-7C in that the tool 320 includes two working zones 321a and 321b separated by a cavity. This type of tool shape allows the working area to be well supported on the periphery of the tooth. In this embodiment, tool 320 further includes two guide pins 325a and 325 b.

In the foregoing embodiment, the tool is mounted so as to be freely rotatable about the tool holder. However, the invention is not limited to this mode of connection, but may also be connected to the inside of the tool holder. In the latter case, the tool is mounted so as to be freely rotatable in the tool holder. Generally speaking, in accordance with the present invention, the tool must be mounted so as to be able to rotate freely with the tool holder.

The tip according to the invention can be used for peripheral dental instruments, such as acoustic or ultrasonic vibration treatment instruments, which, by their ergonomics and functionality, form the end product. An example of this type of instrument is described in particular in document FR 0406630. These tips may also be used with instruments in the form of modules that may be integrated with other modules in a specialized product such as a dental surgical workstation (OEM technology).

Claims (14)

1. Vibrating tip (100) comprising a body (110) having a first end (111) arranged to be rigidly mechanically connected to a vibration generating surgical handpiece (101) and a second end to which a tool holder (112) for reproducing vibrations transmitted by the handpiece is fixed, the tip further comprising a tool (120) mounted so as to be freely rotatable together with the tool holder (112), characterized in that the tool (120) comprises at least one guide pin (125) in its lower part for limiting the penetration depth of said tool (120).

2. The tip according to claim 1, characterized in that the tool (320; 420) comprises two working areas (321a, 321 b; 421a, 421b) for guiding and maintaining the tool in contact with the surface of the tooth (430) to be treated.

3. A tip according to claim 2, characterized in that each guide pin (226) itself comprises a working area.

4. A tip according to claim 2 or 3, wherein the guide pin (226) is formed by a terminal portion (225) of a tool holder (212) passing through the bottom of a cavity (222) formed in the tool (220).

5. The tip according to any of claims 1 to 4, comprising means for limiting the rotation of the tool (120) to a certain angular range.

6. The tip according to any of claims 1 to 5, characterized in that the tool (120) is detachable and interchangeable.

7. The tip according to any of claims 1 to 6, characterized in that the tool (120) is connected to the body (110) of the tip by a connection mechanism allowing free rotation of said tool (120) around the tool holder (112).

8. The tip according to claim 7, characterized in that said connection means comprise at least one rod (123) whose end cooperates with retaining means (115) provided on the tool holder (112) of the tip (100).

9. The tip according to any of claims 1 to 8, characterized in that the tool (120) comprises a cavity (122) forming a housing for the end of the tool holder (112).

10. The tip according to claim 9, characterized in that particles (126) made of flexible material are arranged at the bottom of the cavity (122).

11. A tip according to any one of claims 1 to 10, characterized in that each working area (121) is covered with a friction material.

12. A tip according to any of claims 1 to 10, wherein each working area is subjected to mechanical, chemical or thermal treatment.

13. The tip according to any of claims 1 to 12, characterized in that each working area (121) has a shape corresponding to the treatment to be performed.

14. Ultrasonic dental treatment instrument comprising at least one surgical handpiece connected to an ultrasonic generator, characterized in that it further comprises at least one tip (100; 200; 300) according to any one of claims 1 to 13.