Tool holder apparatus capable of rotating an endodontic instrument, and endodontic device comprising such an apparatus

Abstract

The present invention relates to tool holder apparatus capable of releasably holding an endodontic instrument, said apparatus having a chuck (2) comprising three movable elements angularly distributed about a longitudinal axis (100), each of these movable elements having an inner surface surrounding an inner recess (220), for holding a portion of the endodontic instrument. The inner surface of each of the movable elements has at least one holding portion, these movable elements being movable between a closed configuration, in which the holding portions are parallel to the longitudinal axis and located at the same distance therefrom, and an open configuration, in which the inner surface of said movable elements is further away from the longitudinal axis than in the closed configuration thereof. The invention further relates to a endodontic device comprising such an apparatus.

Description

Instrument-holding equipment capable of rotating an endodontic instrument, and endodontic device comprising such equipment Field of invention

[0001] The present invention relates to devices for performing oral care.

[0002] It relates in particular to rotary oral instruments, which can be rotated to perform work on a tooth, and to instrument-holding equipment capable of holding rotary oral instruments and rotating them.

[0003] It also concerns oral-dental devices composed of such instrument-holder equipment carrying an oral-dental instrument and driving it in rotation.

[0004] In particular, the invention relates to oral-dental devices in which the oral-dental instruments are endodontic instruments. Prior art

[0005] There are several types of rotary dental instruments. Some instruments, such as dental burs, designed to cut teeth, are driven to rotate at high speeds, around 200,000 rpm. In this case, the instrument is driven to rotate with relatively low torque.

[0006] Implantology instruments are also known, designed to cut the jawbone before inserting an implant. Such instruments, which often have a diameter of several millimeters, are generally driven at a relatively slow speed, of the order of a few hundred revolutions per minute, but with a high torque, often between 5 and 50 N / cm, in order to efficiently cut the bone.

[0007] Finally, there are special rotary oral-dental instruments for endodontics, which have a small diameter, generally less than or equal to 1.2 mm, and which are intended to be inserted into the root canal of a tooth. Such endodontic instruments are generally rotated at relatively slow speeds, of the order of a few hundred revolutions per minute. Such endodontic instruments must be driven with a higher torque than dental burs. However, this torque must be precisely controlled and not exceed a ceiling value. Indeed, endodontic instruments are fragile and, in the event of jamming, risk breaking in the root canal of the tooth if too high a torque is applied to them. Thus, generally speaking, endodontic instruments are driven with a torque between 0.5 N / cm and 3 N / cm.

[0008] The present invention applies, in particular, to such rotary endodontic instruments.

[0009] Usually, such endodontic instruments are held and rotated by an oral instrument holder. Such an instrument holder generally comprises a body, which can be held by the practitioner and which may include a motor, and an oral instrument holder head which ensures the holding of the endodontic instrument. This assembly of an endodontic instrument with an oral instrument holder forms the endodontic device. The present invention applies particularly to this type of oral device intended for endodontics.

[0010] Endodontic instruments generally comprise an active portion, which is the portion of the instrument that is intended to perform work on or in the patient's teeth or mouth, and a non-active portion that is intended to be inserted into the instrument-holding equipment head. In prior art endodontic instruments, conventionally, this non-active portion of the instrument intended to be inserted into the instrument-holding equipment head is constituted by a handle, and the active portion of this endodontic instrument is constituted by a blade attached to this handle.

[0011] Such prior art handles often have a standardized shape and dimensions, making them compatible with the head of the instrument-holding equipment that is intended to accommodate them. These handles have a peripheral groove allowing the handle to be locked in an axial direction. They also have a flat surface allowing the head of the instrument-holding equipment to transmit a high torque to it. Such handles most often have standardized characteristics and dimensions, for example corresponding to “Type 1” handles, as defined by the EN ISO 1797 standard concerning rotary oral-dental instruments including endodontic instruments. Disadvantages of the prior art

[0012] The manufacturing cost of endodontic instruments is generally relatively high. Since such instruments are susceptible to fatigue failure, they can only withstand a limited number of uses and are often single-use. They therefore represent a significant source of expense for practitioners.

[0013] For manufacturers of such endodontic instruments, manufacturing is generally carried out in two stages. First, the blade is machined and shaped. Second, this blade is assembled with the handle. This assembly step requires specialized tooling and several operations that are often carried out manually. Furthermore, the manufacture of the handle itself, often made of copper alloys that can be plated with nickel and gold, is relatively expensive. The handle and its assembly to the blade therefore represent a significant part of the manufacturing cost of the endodontic instrument.

[0014] Furthermore, instrument holder heads designed to accommodate standardized “Type 1” handles are relatively bulky, which can be inconvenient for the practitioner. In fact, such large instrument holder heads can obstruct the practitioner’s vision when they are inserted into the patient’s mouth.

[0015] Finally, assembling an endodontic instrument into an instrument holder head requires rotating the handle on itself to the unique angular position in which its flat is aligned with the corresponding surface of the instrument holder head. This assembly complicates the use of the endodontic equipment by the practitioner. Objectives of the invention

[0016] The present invention aims to overcome these drawbacks of the prior art.

[0017] In particular, the present invention aims to enable a reduction in the manufacturing costs of endodontic instruments. Its particular objective is to reduce the number of manual interventions and specific machines used for the manufacturing and assembly of such instruments.

[0018] Another particular objective of the invention is to allow the use of endodontic instruments whose cost is reduced, compared to the endodontic instruments with which dental practitioners are usually equipped.

[0019] Yet another objective of the invention is to enable the use of endodontic devices, composed of an endodontic instrument carried by an instrument-holding equipment head, which have a reduced footprint in the patient's mouth, and thus which allow easier access, for the practitioner, to the area to be treated in the patient's mouth, and a better view of this area, during treatment.

[0020] Another objective of the invention is also to facilitate the assembly, by the practitioner, of an endodontic instrument in an instrument-holding equipment head.

[0021] These objectives, as well as others which will appear more clearly hereinafter, are achieved using an instrument-holding device, capable of removably holding an endodontic instrument, this instrument-holding device comprising a mandrel, pivotally mounted in the instrument-holding device, around a longitudinal axis, this mandrel having a first end, on the longitudinal axis, and a second end, opposite the first end on the longitudinal axis, the mandrel comprising exactly three movable elements distributed angularly around the longitudinal axis, these movable elements each comprising an internal surface surrounding an internal housing defined in the mandrel, which extends along the longitudinal axis and is open at the second end, this internal housing being capable of receiving a portion of the endodontic instrument.According to the invention, the internal surface of each of the movable elements has at least one flat or substantially flat holding portion, these movable elements being movable between a closed configuration, in which the holding portions are substantially parallel to the longitudinal axis, and located at the same distance from this longitudinal axis, and an open configuration, in which their internal surface is further from the longitudinal axis than in their closed configuration.

[0022] By "comprising exactly three movable elements distributed angularly around the longitudinal axis" is meant that these movable elements are three in number, no more, no less. This does not prevent the mandrel from comprising other elements, which may also be movable, but which do not have the characteristics of the three movable elements described above.

[0023] In the present description, surfaces which would be considered to be planar by a person skilled in the field of dental equipment are referred to as "planar" or "substantially planar". Similarly, surfaces which would be considered to be parallel to this axis by a person skilled in the field of dental equipment are referred to as "parallel to an axis" or "substantially parallel to an axis".

[0024] Such an instrument-holding device according to the present invention makes it possible to center and removably hold a small-diameter endodontic instrument, being capable of rotating it by transmitting a relatively high torque to it. Thus, this instrument-holding device can, for example, receive an endodontic instrument consisting of a simple blade, fitting into a cylindrical envelope which may have a diameter of 1.2 mm, or even 0.8 mm. Despite the absence, on such an instrument, of a large “Type 1” handle, the instrument-holding device according to the invention is capable, thanks in particular to its holding portions, of rotating such an instrument by transmitting sufficient torque to it to carry out endodontic treatment. Such an instrument-holding device according to the invention can also have a reduced footprint, thereby offering better visibility to the dental practitioner who uses it.

[0025] The internal triangular shape of the chuck allows the instrument holder to accommodate endodontic instrument blades with very small diameters. In addition, this triangular shape allows the instrument holder to hold blades with a greater variability of diameters than an instrument holder with a pentagonal or hexagonal shape. More specifically, the contact surface between the moving elements and the blade of the endodontic instrument, which preferably fits into an equilateral triangle, allows the transfer of significant torque, including on blades with small diameters.

[0026] This technical solution makes it possible to overcome a prejudice held by those skilled in the art who usually thought that blades with too small diameters, and in particular diameters less than 1.6 mm, must necessarily be carried by handles with larger diameters in order to be able to transfer sufficient torque to them. On the contrary, the mandrel of the instrument-holding equipment according to the invention can hold an endodontic instrument blade with a diameter of 0.8 mm as well as an endodontic instrument blade with a diameter of 1.2 mm, and transfer to them the torque usually used in endodontic operations.

[0027] Advantageously, the movable elements are constituted by elongated legs extending between two ends, a first end of each leg being fixed to another part of the mandrel and the second end of each leg being free, and forming the second end of the mandrel, the internal housing being formed between the legs.

[0028] Preferably, these legs are able to deform elastically, in order to be mobile relative to each other.

[0029] The legs can thus move easily to allow the insertion or removal of a portion of an endodontic instrument into the internal housing of the mandrel.

[0030] According to an advantageous embodiment, the mandrel comprises restraining means movable between a so-called locking position, in which they maintain the movable elements in the closed configuration, and a so-called unlocking position, in which they do not maintain the movable elements in this closed configuration.

[0031] These mobile retention means ensure that the mobile elements are held in their closed configuration when they are in the so-called locking position, thus preventing the removal of an endodontic instrument placed in the internal housing.

[0032] Preferably, these restraining means surround the legs and are slidable along them, in a direction parallel to the longitudinal axis, between their locked position and their unlocked position.

[0033] This makes it very easy to move the restraints from their locked position to their unlocked position, and vice versa.

[0034] In this case, preferably, the restraint means comprise a helical spring surrounding the legs.

[0035] This helical spring can thus itself form the movable restraint means between a locking position in which it maintains the legs in their closed configuration, and an unlocking position in which it does not maintain the legs in this closed configuration. It is also possible for it to push another component, such as for example a ring surrounding the legs, towards its position corresponding to the locking position of the restraint means.

[0036] Advantageously, the internal surfaces have at least one shoulder oriented towards the first end of the mandrel.

[0037] This shoulder of the internal surfaces can advantageously participate in maintaining in the mandrel a portion of endodontic instrument having a complementary shape, preventing its removal from the internal housing.

[0038] According to a preferred embodiment, the holding portions, in the closed configuration, are located at a distance from the longitudinal axis of less than 0.4 mm.

[0039] The holding portions can thus contribute to effectively holding a small endodontic instrument in the chuck and rotating it, transmitting sufficient torque to perform endodontic treatment. This instrument can thus be a simple blade, formed from a cylindrical rod with a diameter of 1.2 mm, or even 0.8 mm.

[0040] In the case where the chuck is designed to hold blades of 0.8 mm diameter, the holding portions, in the closed configuration, are advantageously located at a distance from the longitudinal axis of less than 0.3 mm.

[0041] Advantageously, the holding portions, in the closed configuration, form angles of 60° between them.

[0042] This angular distribution of the surfaces of the holding portions, which are inscribed in an equilateral triangle, allows an endodontic instrument to be placed in the chuck in 3 different angular positions. This makes it easier for the practitioner to place an endodontic instrument in the chuck.

[0043] The present invention also relates to an endodontic device, comprising an instrument-holding device as described above and an endodontic instrument, a portion of which is introduced into the internal housing, the movable elements and this portion of the endodontic instrument having complementary shapes, such that the movable elements maintain the portion of the endodontic instrument in the internal housing, when they are in the closed configuration, called the first configuration, and allow the withdrawal of the endodontic instrument from this internal housing, when they are in the open configuration, called the second configuration.

[0044] This holding of the endodontic instrument, in the closed configuration, by three substantially flat holding portions, substantially parallel to the longitudinal axis and located at the same distance from this longitudinal axis, allows effective centering of the instrument and rotational drive, with sufficient torque to carry out endodontic treatment, even when the instrument has small dimensions, smaller than the dimensions of the handles of instruments commonly used in the prior art.

[0045] According to a preferred embodiment, the endodontic instrument consists of a blade inscribed in a cylindrical envelope with a diameter less than or equal to 1.6 mm, or even less than or equal to 1.2 mm.

[0046] Particularly advantageously, the portion of the endodontic instrument which is inserted into the internal housing is inscribed in a cylindrical envelope with a diameter less than or equal to 0.8 mm.

[0047] The endodontic instrument can thus be formed from a simple blade, and be devoid of the handle which equipped most of the endodontic instruments of the prior art.

[0048] Preferably, this portion of the endodontic instrument has three flats, distributed angularly around its perimeter, in contact with the holding portions when the mobile elements are in the closed configuration.

[0049] This arrangement ensures that the endodontic instrument is held in the mandrel, preventing it from becoming detached from it when the moving elements are in the closed configuration, and allows it to be driven in rotation efficiently, with sufficient torque to carry out endodontic treatment. List of figures

[0050] The invention will be better understood upon reading the following description of preferred embodiments, given as a simple figurative and non-limiting example, and accompanied by the figures among which:1a is a sectional view of an instrument holder head according to an embodiment of the invention, along a plane passing through the longitudinal axis of the instrument.1a is a first cross-sectional view of the instrument holder equipment head of the.1a is a second cross-section of the instrument holder equipment head of the.1a is a third cross-section of the instrument holder equipment head of the.1a is a fourth cross-section of the instrument holder equipment head of the.1a is a perspective view of the mandrel of the instrument holder equipment head of the, in an open configuration.1a is a perspective view of the mandrel of the instrument holder equipment head of the, in a closed configuration.lais a sectional view along a longitudinal plane of the mandrel of the instrument-holding equipment head of la.lais a side view of the end of an endodontic instrument intended to be placed in the instrument-holding equipment head.lais a sectional view of the end of an endodontic instrument intended to be placed in the instrument-holding equipment head.lais a perspective view of an endodontic instrument according to an embodiment of the invention.lais a perspective view of the endodontic instrument of la, placed in a sheath.lais a perspective view of the mandrel of the instrument-holding equipment head of lain a closed configuration, cooperating with the endodontic instrument and the sheath of la.lais a perspective view of the mandrel of the instrument-holding equipment head of lain a closed configuration, holding the endodontic instrument of la.lais a sectional view of the non-active portion of an endodontic instrument, adapted to perform irrigation.lais a sectional view of the non-active portion of another endodontic instrument, adapted to perform irrigation.lais a sectional view of a head of an instrument-holding equipment according to another embodiment of the invention, adapted to perform irrigation.lais a sectional view of a head of an instrument-holding equipment according to yet another embodiment of the invention, adapted to perform irrigation.lais a sectional view of an instrument-holding head according to yet another embodiment of the invention.lais a side view of a part of an endodontic instrument intended for the instrument-holding equipment head of la, placed in a sheath, a part of which is shown in section.lais a perspective view of the endodontic instrument and sheath parts represented by la.Detailed description of an embodiment of the invention.

[0051] An instrument-holding device is a dental device comprising a body, intended to be held by the hand of a dental practitioner, and a head, assembled to the body, having means for holding a dental instrument. The body of the instrument-holding device often includes drive means, such as a motor, for rotating the instrument held by the head of the instrument-holding device.

[0052] La represents an instrument-carrying equipment head 1 according to an embodiment of the invention, in sectional view along a plane passing through the longitudinal axis 100, which corresponds to the axis of rotation of the instrument which can be carried by this instrument-carrying equipment head 1.

[0053] The instrument-carrying equipment head 1 comprises a housing 11 which is intended to be assembled to the body of an instrument-carrying equipment. A sleeve 12 is mounted in the housing 11 by means of bearings 121 and 122, so as to be pivotable, relative to the housing 11, around the longitudinal axis 100. The external face of this sleeve 12 forms a toothed wheel 123. This toothed wheel 123 can be engaged with a drive pinion, not shown in the, which can for example be linked to a drive shaft coming from the body of the instrument-carrying equipment, and capable of transmitting to the toothed wheel 123 of the sleeve 12 a rotary movement coming from a drive motor.

[0054] At one end, called the front end 120 of the sleeve 12, the sleeve 12 is open to allow an endodontic instrument to be carried by the instrument-holder equipment head 1 to be inserted therein. At another end, called the rear end 129 of the sleeve 12, opposite the front end 120, the housing 11 is closed by a cap 111.

[0055] A mandrel 2 is mounted in the sleeve 12, securely attached to this sleeve 12. This mandrel 2 is intended to hold an endodontic instrument and to drive it in rotation, with a torque adapted to carrying out an endodontic treatment.

[0056] The mandrel 2 is visible in longitudinal section view, along a plane passing through the longitudinal axis 100, in the, in cross section, perpendicular to the longitudinal axis 100, in figures 2 to 5, and in perspective, separated from the other elements of the instrument-carrying equipment head 1, in figures 6 and 7.

[0057] This mandrel 2 is elongated along the longitudinal axis 100, and is inscribed in a cylindrical envelope whose axis corresponds to the longitudinal axis 100. It has a first end 25 on the longitudinal axis 100, held close to the rear end 129 of the sleeve 12, and a second end 26, opposite its first end 25 on the longitudinal axis 100, which is held close to the front end 120 of the sleeve 12.

[0058] Near its first end 25, the mandrel 2 has an assembly portion 21, which is intended to be assembled to the other elements of the instrument-holder equipment head 1. In the embodiment shown, this assembly portion 21 is a cylindrical portion, intended to be force-fitted into the cylindrical opening of the sleeve 12, near its rear end 129.

[0059] Advancing towards its second end 26, the mandrel 2 continues with an intermediate portion 23, which is a cylindrical portion concentric with the assembly portion 21, but of smaller diameter. This intermediate portion 23 is represented by the section of the. It should be noted that the helical spring 29, which surrounds this intermediate portion 23, is not shown in Figures 2 to 5.

[0060] The mandrel 2 has an internal housing 220 open on its second end 26, and extending along the longitudinal axis 100, over a portion of the length of the mandrel 2. This internal housing 220 is intended to receive the non-active portion of a blade of an endodontic instrument. According to the invention, this internal housing 220 is surrounded by several elements of the mandrel 2, which are movable relative to each other.

[0061] In the embodiment shown, the portion of the mandrel 2 which surrounds the internal housing 220 is formed by three distinct and identical tabs 22. These tabs 22 form the movable elements of the mandrel 2. Each of these three tabs 22 is secured, by one of its ends, to the intermediate portion 23 of the mandrel 2. From this intermediate portion 23, each of the three tabs 22 extends substantially parallel to the longitudinal axis 100 of the mandrel 2, to its free end, at the level of the second end 26 of the mandrel 2.

[0062] Each of these legs 22 has an external surface 221, the greater part of which is in line with the cylindrical external shape of the intermediate portion 23. At the free end of the legs 22, these external surfaces 221 have stops 225, the surface of which is further from the longitudinal axis 100 than the rest of the external surface 221 of the legs 22.

[0063] Each of these legs 22 also has an internal surface 226 surrounding the internal housing 220, and forming the surface of this internal housing 220. This internal surface 226 has a variable shape along the leg 22, from the intermediate portion 23 to the second end 26 of the instrument. This shape of the internal surface 226 is described below, in connection with figures 2 to 5 and the sectional view of the.

[0064] La represents a cross-section CC of the instrument-carrying equipment head 1, showing a section of the legs 22 close to the intermediate portion 23. At this section, each of the legs 22 advantageously has a reduced section compared to the neighboring portions of the leg 22, and therefore a lower moment of inertia, so as to form a flexible hinge 222, this flexible hinge 222 being defined by the shape of the internal surface 226 of the leg 22, which is locally closer to the external surface 221. The mandrel 2 being advantageously made of a material having a high elasticity, such as for example a nickel-titanium alloy, the legs 22 can deform elastically, in particular at the flexible hinges 222, in order to be movable relative to each other.

[0065] La represents another cross-section DD of the instrument-carrying equipment head 1, showing a section of the legs 22, further from the intermediate portion 23 than the section represented by la. At this section, the internal surfaces 226 of each of the three legs 22 form a first surface portion 223.

[0066] In the configuration represented by figures 7 and 8, each of these first surface portions 223 is substantially planar and parallel to the longitudinal axis 100 of the mandrel 2, and is distant from this longitudinal axis 100 by a distance D1 which is, in the embodiment represented, substantially equal to 0.4 mm.

[0067] La represents another cross-section EE of the instrument-carrying equipment head 1, showing a section of the legs 22, further from the intermediate portion 23 than the section represented by la. At this section, the internal surfaces 226 of each of the three legs 22 form a second surface portion, also called holding portion 224, which is substantially planar, and closer to the longitudinal axis 100 than the first surface portions 223. These holding portions 224 of the three legs 22 are advantageously arranged in such a way that together they form portions of the sides of an equilateral triangle centered on the longitudinal axis 100 of the mandrel 2.

[0068] In the first configuration called the “closed configuration” of the mandrel 2 shown in Figures 7 and 8, each of these holding portions 224 is substantially parallel to the longitudinal axis 100. Furthermore, these holding portions 224 are preferably spaced apart from this longitudinal axis 100 by the same distance D2. To effectively hold an endodontic instrument without a handle, this distance D2 can advantageously be less than 0.4 mm. Thus, in the embodiment shown, in which the mandrel 2 carries an instrument formed from a bar with a diameter of 0.8 mm, each of these holding portions 224 is spaced apart from the longitudinal axis 100 by a distance D2 which is, in the embodiment shown, substantially equal to 0.3 mm.

[0069] The first surface portion 223 and the holding portion 224 are connected to each other by a shoulder 227. This shoulder 227 is a portion of the internal surface 226 which can provide support for blocking a movement along the longitudinal axis 100. In this embodiment, the shoulder 227 extends substantially in a plane perpendicular to the longitudinal axis 100 and is oriented towards the first end 25 of the mandrel 2. It therefore makes it possible to provide support for a component inserted in the internal housing 220 coming into contact with the shoulders 227, this support blocking the translation of this component along the longitudinal axis 100 towards the second end 26 of the mandrel 2.

[0070] It should be noted that, in certain embodiments, such a shoulder may have an angle relative to the perpendicular to the longitudinal axis 100, for example to form a chamfer. Thus, any surface portion making it possible to provide a support capable of blocking a translation along the longitudinal axis 100 may be considered as forming a shoulder within the meaning of the present description. This is particularly the case, for example, for several complementary chamfers which together make it possible to block a translation, along the longitudinal axis 100, of a complementary shape of an instrument bearing on these chamfers.

[0071] In the longitudinal sectional view of the mandrel 2 of the, the internal surface 226 of the legs 22 forms a third surface portion 228, further from the intermediate portion 23 than the holding portions 224 shown in the section of the. This third surface portion 228 forms an entry portion of the internal housing 220, widening as it approaches the second end 26 of the mandrel 2, corresponding to the free end of the legs 22, to form a chamfer facilitating the introduction of a blade into the internal housing 220.

[0072] The three legs 22 of the mandrel 2 are separated from each other by slots extending longitudinally on the mandrel 2. According to an advantageous embodiment, these slots are formed by cutting using an electroerosion wire, extending in a plane transverse to the longitudinal axis 100, which is moved relative to the mandrel 2 in order to form the internal surfaces 226 of each of the legs 22. Consequently, when the legs 22 are in their closed configuration, all the portions of the internal surfaces 226 of the legs 22 have at least one generatrix constituted by a straight line not colliding with another surface of the mandrel 2.

[0073] In the embodiment shown, the slots separating the three legs 22 are substantially rectilinear, and parallel to the longitudinal axis 100. It is however possible, in other embodiments, for these slots to have different shapes, for example helical slots centered on the longitudinal axis 100.

[0074] To form the flexible hinge portion 222, the EDM wire which is used to cut the internal surfaces 226 of the legs 22 can be moved, in a plane transverse to the longitudinal axis 100 of the mandrel 2, in order to make the cuts locally reducing the cross-section of the legs 22.

[0075] As shown in Figures 6 and 7, a helical spring 29 surrounds the intermediate portion 23 and the external surface 221 of the legs 22, up to the stops 225. When this helical spring 29 is relaxed, in its position called the “locking position” represented by 1a, it bears on the assembly portion 21, on one side, and on the stops 225, on the other side.

[0076] The dimensions of the helical spring 29, and in particular its internal diameter, and the shape and dimensions of the external surface 221 of the legs 22 near the stops 225 are such that, when the helical spring 29 is in this locking position, its turns bearing against the stops 225 surround the external surfaces 221 of the legs 22, keeping these legs 22 in their closed configuration.

[0077] In this closed configuration, the legs 22 do not allow the introduction of an endodontic instrument into the internal housing 220 which they surround. On the other hand, if a suitable endodontic instrument is placed in this internal housing 220, it is held by the legs 22 without being able to be removed.

[0078] The helical spring 29 can also be compressed, as shown in 1a, into a position called the “unlocking position” in which it only partially surrounds the legs 22 and is no longer in abutment against the stops 225. The shape of the external surfaces 221 of the legs 22 is such that, in this unlocking position of the helical spring 29, this helical spring 29 no longer maintains the legs 22 in their closed configuration but, on the contrary, allows them to move slightly apart from each other, into their second configuration called the “open configuration” shown in 1a. In this open configuration, the legs 22 can move slightly apart from each other. They then allow the introduction of an endodontic instrument into the internal housing 220 which they surround, or the removal of such an endodontic instrument.

[0079] The helical spring 29 thus forms a movable restraining means between a locking position, represented by 1a, in which it maintains the legs 22 in their closed configuration, and an unlocking position, represented by 1a, in which it does not maintain the legs 22 in their closed configuration.

[0080] In the embodiment shown by these figures, the tabs 22 are advantageously in a rest position when they are in their open configuration, and are elastically deformed to move to their closed configuration. Thus, when the helical spring 29 moves into its unlocked position, these tabs 22 can move, without further intervention, into their open configuration. In other embodiments, the tabs 22 may be in their rest position when they are in their closed configuration. In this case, the separation of the tabs 22 to move them into their open configuration may for example be obtained by introducing an object into the internal housing 220 between these tabs 22.

[0081] The chuck 2 is designed to receive a specially adapted endodontic instrument, which can advantageously be formed of a simple blade, which is not assembled to a handle. Thus, for example, the represents an endodontic instrument formed by the blade 3, which has a first end, or assembly end 31, forming the end of its non-active portion 35, and a second end, or free end 37, forming the end of its active portion 36.

[0082] The active portion 36 is the part of the instrument which extends from its free end 37 and which is intended to be introduced into the root canal of a tooth, in order to carry out work or cleaning there. This active portion 36 thus has a specific shape, generally obtained by machining, which allows it to carry out the necessary work inside this root canal. In the, this active portion 36 is represented schematically by a cone. It is however common for such an active portion 36 of an endodontic instrument to have a helical shape, fitting into a cone. Those skilled in the art will of course be able to produce the blade 3, or an equivalent blade, with an active portion 36 having any known shape.

[0083] The non-active portion 35 of the blade 3 is a portion of the blade 3 intended to connect the active portion 36 to the instrument-holding equipment. This non-active portion 35 is inscribed in the cylindrical shape of the bar in which the blade 3 is machined, which is, in the embodiment shown, a bar with a diameter of 0.8 mm. The axis of this cylindrical shape is subsequently designated as the longitudinal axis 300 of the blade 3, which corresponds, when the blade 3 is assembled to the mandrel 2 of the instrument-holding equipment head 1, to the longitudinal axis 100 of the mandrel 2.

[0084] This non-active portion 35 of the blade 3 is shown in detail by la and in cross-sectional view by la. Near its assembly end 31, this non-active portion 35 first has a short end segment 32, having three main flat surfaces parallel to the longitudinal axis 300, positioned in such a way that the cross-section of this end segment 32 is inscribed in an equilateral triangle centered on the longitudinal axis 300 of the blade 3. At the assembly end 31, this end segment 32 advantageously ends with chamfers 310 approaching the longitudinal axis 300. Next to this end segment 32, the non-active portion 35 has a holding segment 33, around which three flats 34 are distributed.These flats 34 preferably form flat surfaces parallel to the longitudinal axis 300, positioned in such a way that the cross-section of this holding segment 33, which is visible in the figure, is inscribed in an equilateral triangle centered on the longitudinal axis 300 of the blade 3. In the embodiment shown, each of these flats 34 is located at a distance of 0.3 mm from the longitudinal axis 300.

[0085] These flats 34 are advantageously closer to the longitudinal axis 300 of the blade 3 than the main flat surfaces of the end segment 32, such that shoulders 341 appear at the junction between the flats 34 and the end segment 32. These shoulders 341 are parts of the surface of the blade 3 which can provide support making it possible to block a movement of the blade 3 along its longitudinal axis 300. They are advantageously oriented towards the free end 37 of the blade 3, and can extend in a plane substantially perpendicular to the longitudinal axis 300. It is however possible for these shoulders 341 to be inclined relative to a plane substantially perpendicular to the longitudinal axis 300.

[0086] It should be noted that the blade 3 can also be manufactured from a cylindrical bar of different diameter, and in particular of larger diameter. It is thus possible, for example, to manufacture it from a bar with a diameter of 1.2 mm. In this case, the non-active portion 35 of the blade 3 can have flats 34 located at a distance of 0.3 mm from the longitudinal axis 300 which form an equilateral triangle centered on this longitudinal axis 300. Such flats are very easy to obtain, regardless of the diameter of the bar in which the blade is formed.

[0087] According to the invention, the mandrel 2 can receive and hold, reversibly, a suitable blade such as the blade 3, the non-active portion of the blade being introduced into the internal housing 220 of the mandrel 2. The following description describes the assembly of the blade 3 with the mandrel 2.

[0088] In the unlocked position of the helical spring 29, when it is pushed back towards the intermediate portion 23, the helical spring 29 only partially surrounds the legs 22, the legs 22 then being able to move away from each other and pass into their open configuration. This passage can be done by the elastic return effect, if the rest position of the legs 22 corresponds to their open configuration, or under the effect of an action moving the legs 22 away from each other, if the rest position of the legs 22 corresponds to their closed configuration.

[0089] When the coil spring 29 is in the unlocked position, the non-active portion 35 of the blade 3 can be inserted between the legs 22 of the mandrel 2. In the embodiment shown, the blade 3 can penetrate until the assembly end 31 of the blade 3 comes into contact with the intermediate portion 23 of the mandrel 2. In this position, the end segment 32 of the blade 3 is located in the segment of the internal housing 220 of the mandrel 2 which is defined by the first surface portions 223.

[0090] The non-active portion 35 of the blade 3 advantageously has dimensions such that, when the assembly end 31 of the blade 3 is in contact with the intermediate portion 23, the flats 34 are opposite the segment of the internal housing 220 defined by the holding portions 224.

[0091] When the blade 3 is in this position in the internal housing 220, the helical spring 29 can then return to its locking position. The tabs 22 then return to their closed configuration, if necessary by slightly rotating the blade 3 around its longitudinal axis 300, in order to ensure the alignment of the surfaces of the holding portions 224 and the flats 34. Once returned to its locking position, the helical spring 29 maintains the tabs 22 in their closed configuration, in which the holding portions 224 are in contact with the flats 34.

[0092] At this moment, the non-active portion 35 of the blade 3 is then locked in the mandrel 2 in its closed configuration. Indeed, the end segment 32 of the blade 3 is introduced into the internal housing 220 so that the assembly end 31 of the blade 3 comes into contact with the intermediate portion 23 of the mandrel 2, which blocks the translation of the blade 3 in a direction tending to bring the blade 3 closer to the mandrel 2. In addition, the shoulders 227 of the legs 22 of the mandrel 2, having come into contact with the shoulders 341 joining the flats 34 to the end segment 32 of the blade 3, prevent the blade 3 from being removed from the mandrel 2, as long as this mandrel 2 is in its closed configuration. Finally, the holding portions 224 of the legs 22, in contact with the flats 34, center the blade 3 relative to the mandrel 2, such that the longitudinal axis 300 of the blade 3 corresponds to the longitudinal axis 100 of the mandrel 2.

[0093] The introduction of an endodontic instrument into the mandrel 2, or the removal of an endodontic instrument from this mandrel 2 requires pushing the movable retention means from their locking position to their unlocking position. In the embodiment shown in Figures 1 to 7, it is thus necessary to push the helical spring 29 towards the intermediate portion 23, which is difficult to implement without suitable equipment.

[0094] To facilitate this manipulation, the endodontic instrument which must be introduced into the mandrel 2 can advantageously be equipped with a specific sheath, allowing the retention means of the mandrel 2 to pass into their unlocking position. The figure thus represents, by way of example, the blade 3 inserted into such a sheath 7.

[0095] This sheath 7 advantageously has a case 71 surrounding the active portion 36 of the blade 3. This case 71, of tubular shape, can be made of a relatively flexible plastic and can be open, close to the tip of the active portion 36 of the blade 3, or on the contrary be closed, for example in order to keep this active portion 36 sterile. At its end closest to the assembly end 31 of the blade 3, the sheath 7 forms a rigid crown having three fingers 72, which extend along the non-active portion 35 of the blade 3, in a direction parallel to the longitudinal axis 300 of this blade 3, in the direction of its assembly end 31.

[0096] The dimensions and shape of these fingers 72 are chosen so as to allow their introduction into the slots located between the legs 22 of the mandrel 2, when the non-active portion 35 of the blade 3 is introduced into the internal housing 220 located between these legs 22. This introduction into the mandrel 2 of a blade 3, surrounded by a sheath 7, is represented by the. During this introduction, the ends of the fingers 72 come into contact with the helical spring 29 to push it back towards its unlocking position.

[0097] Preferably, the sheath 7 has, between these fingers 72, inclined planes 73 capable, when the fingers 72 are introduced into the slots located between the tabs 22, of coming into contact with the third surface portions 228 of the tabs 22 to separate these tabs 22 from each other.

[0098] The sheath 7 thus allows the mandrel 2 to pass from its closed configuration represented by to its open configuration represented by, together with the introduction of the blade 3 into this mandrel 2.

[0099] Once the non-active portion 35 of the blade 3 is inserted into the internal housing 220 of the mandrel 2, the sheath 7 can be removed, while maintaining the blade 3 in the mandrel 2. The mandrel 2 then returns to its closed configuration, securely maintaining the blade 3, as shown in.

[0100] The removal of the blade 3 from the mandrel 2 can be achieved by replacing the sheath 7 on the blade 3, such that the fingers 72 are inserted into the slots located between the legs 22 of the mandrel 2, pushing back the helical spring 29, and the third surface portions 228 of the legs 22 are separated by the inclined planes 73, such that the legs 22 move away from each other. The mandrel 2 then returns to its open configuration, and the blade 3 can be removed from the mandrel 2, for example at the same time as the sheath 7.

[0101] According to particular embodiments, an instrument-holder equipment head 1 according to one embodiment of the invention can be adapted to supply irrigating liquid to an instrument specially adapted to conduct this irrigating fluid into the patient's tooth.

[0102] Figures 17 and 18 show two examples of such instrument-carrying equipment heads 1. In these two embodiments, the mandrel 2 equipping the instrument-carrying equipment heads 1 has an axial conduit 24 passing through the assembly portion 21 and the intermediate portion 23, along the longitudinal axis 100. This axial conduit 24 therefore opens on the one hand onto the first end 25 of the mandrel 2, and on the other hand at the bottom of the internal housing 220.

[0103] Such a mandrel 2 can receive a specifically adapted instrument, such as the instruments 301 and 302 whose non-active portions are represented, respectively, by figures 15 and 16. These instruments 301 and 302 have axial conduits, respectively 3010 and 3020, extending along their longitudinal axis 300. The instrument 302 represented by the also comprises a conduit portion 3021 extending its non-active portion, which is capable of being introduced into the axial conduit 24 of the mandrel 2.

[0104] At the first end 25 of the mandrel 2, the cover 112 of the housing 11 is adapted to allow the supply of fluid to the axial pipe 24 of the mandrel 2. Thus, this cover 112 may have an opening aligned with the longitudinal axis 100, as represented by la, or a fluid supply chamber 113, facing the first end 25 of the mandrel 2, which is itself supplied by a supply pipe 114, as represented by la.

[0105] Laest is a sectional view of an instrument-holding equipment head 1 according to another possible embodiment of the invention. This instrument-holding equipment head 1 has a housing 11 and a socket 12 similar to those of the instrument-holding equipment head 1 of the. The socket 12 holds a mandrel 2 which, as shown in the, has an assembly portion 21, an intermediate portion 23 and three legs 22, extending the intermediate portion 23 and defining an internal housing 220 capable of receiving the non-active portion 35 of a blade such as the blade 3.

[0106] The external surface 221 of the legs 22 has, at the free end of the legs 22, stops 225. A ring 27 is slidably mounted around the external surface 221 of the legs 22 and the intermediate portion 23 of the sleeve 12. It is held in contact with the stops 225 by a helical spring 29 surrounding the legs 22 and the intermediate portion 23.

[0107] This helical spring 29 and this ring 27 constitute restraining means. When the ring 27 is in contact with the stops 225, these restraining means are in their locking position, in which they maintain the legs 22 in their closed configuration. On the contrary, when the ring 27 is pushed towards the assembly portion 21 of the mandrel 2, by compressing the helical spring 29, these restraining means are in their unlocking position in which they allow the legs 22 to move away from each other to reach their open configuration.

[0108] This instrument-holder equipment head 1 represented by is intended to be used with the blade 3 surrounded by a sheath 8, as shown in. This shows the non-active portion 35 of the blade 3, surrounded by a sheath 8 which is shown in sectional view. The also shows, in perspective, the non-active portion 35 of the blade 3 and a portion of the sheath 8.

[0109] The sheath 8 has a circular opening forming a crown 81, surrounding the assembly end 31 of the blade, which is capable of pushing the ring 27 towards its unlocking position, passing between the sleeve 12 and the lugs 22. The dimensions of this crown 81 are such that it does not hinder the spacing of the lugs 22, when these pass into their open configuration. Thus, when the non-active portion 35 of the blade 3 surrounded by the crown 81 of the sheath 8 as shown in FIGS. 20 and 21 is introduced into the internal housing 220 of the mandrel 2, the sheath 8 pushes the ring 27 towards its unlocking position at the very moment when the assembly end 31 of the blade 3 enters the internal housing 220, between the lugs 22 which then pass into their open configuration.

Claims

Instrument-holding equipment, capable of removably holding an endodontic instrument, said instrument-holding equipment comprising a mandrel (2), pivotally mounted in said instrument-holding equipment, around a longitudinal axis (100), said mandrel having a first end (25), on said longitudinal axis, and a second end (26), opposite said first end on said longitudinal axis, said mandrel comprising exactly three movable elements distributed angularly around said longitudinal axis, said movable elements each comprising an internal surface (226) surrounding an internal housing (220) defined in said mandrel, which extends along said longitudinal axis and is open at said second end, said internal housing being capable of receiving a portion of said endodontic instrument, said internal surface (226) of each of the movable elements having at least one flat holding portion (224),said movable elements being movable between:- a closed configuration, in which said holding portions (224) are substantially parallel to said longitudinal axis (100), and located at the same distance from said longitudinal axis (100),- and an open configuration, in which their internal surface (226) is further from said longitudinal axis (100) than in their closed configuration., Instrument-carrying equipment according to the preceding claim, characterized in that said movable elements are constituted by elongated legs (22) extending between two ends, a first of said ends of each leg being fixed to another part of said mandrel (2) and the second of said ends of each leg being free, and forming said second end (26) of said mandrel, said internal housing (220) being formed between said legs. Instrument-carrying equipment according to the preceding claim, characterized in that said legs (22) are capable of deforming elastically, in order to be movable relative to each other. Instrument-carrying equipment according to any one of the preceding claims, characterized in that said mandrel (2) comprises restraining means movable between a so-called locking position, in which they maintain said movable elements in said closed configuration, and a so-called unlocking position, in which they do not maintain said movable elements in said closed configuration. Instrument-carrying equipment according to claims 2 and 4, characterized in that said restraining means surround said legs (22), and are sliding along said legs, in a direction parallel to said longitudinal axis (100), between their locked position and their unlocked position. Instrument-carrying equipment according to claim 5, characterized in that said restraining means comprise a helical spring (29) surrounding said legs (22). Instrument-carrying equipment according to any one of the preceding claims, characterized in that said internal surfaces (226) have at least one shoulder (227) oriented towards said first end (25) of said mandrel (2). Instrument-carrying equipment according to any one of the preceding claims, characterized in that said holding portions (224), in said closed configuration, are located at a distance from said longitudinal axis (100) of less than 0.4 mm. Instrument-carrying equipment according to any one of the preceding claims, characterized in that said holding portions (224), in said closed configuration, form angles of 60° between them. Endodontic device, comprising an instrument-holding device according to any one of the preceding claims and an endodontic instrument, a portion of which is introduced into said internal housing (220), said movable elements and said portion of said endodontic instrument having complementary shapes, such that said movable elements:- hold said portion of said endodontic instrument in said internal housing, when they are in said closed configuration, and- allow the removal of said endodontic instrument from said internal housing, when they are in said open configuration. Endodontic device according to the preceding claim, characterized in that said endodontic instrument consists of a blade (3) inscribed in a cylindrical envelope with a diameter less than or equal to 1.6 mm. Endodontic device according to any one of claims 10 and 11, characterized in that said portion of said endodontic instrument is inscribed in a cylindrical envelope with a diameter less than or equal to 0.8 mm. Endodontic device according to any one of claims 10 to 12, characterized in that said portion of said endodontic instrument has three flats (34), distributed angularly around its perimeter, in contact with said holding portions (224) when said movable elements are in said first configuration.

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