Probe fixation tool in a dental implant

Abstract

Probe Fixing Tool in a Dental Implant. The invention relates to a tool for screwing an ultrasonic probe into a dental implant that is fixed in the bone of a patient's mouth. The tool comprises a body having a proximal portion (111) and a distal portion (112). The proximal portion (111) of the body includes a handle or gripping interface (1110) to allow a practitioner to grasp the body by hand in order to apply a rotational moment about a longitudinal axis (A) of the body. The distal portion (112) of the body includes a deformable portion (1120) adapted to engage with the probe head and surrounding a central cavity (E) that is centered on said longitudinal axis of the body. Figure for the abstract: Fig. 3E

Description

Title of the invention: Probe fixation tool for a dental implant. Technical field

[0001] The present invention relates to a clamping tool for an ultrasonic probe in a dental implant which is fixed in the bone of the mouth of a patient. STATE OF THE ART

[0002] It is important to be able to control the stability of a dental implant fixed in the bone of a patient's mouth. This stability is necessary for proper implantation and therefore for the effectiveness of the implant.

[0003] There are known means for carrying out such a control.

[0004] In particular, a probe is known which allows the stability of a dental implant fixed in the bone of a patient's mouth to be checked by analyzing ultrasonic signals.

[0005] Such a probe may include an ultrasonic transducer intended to be coupled to the implant (for example by screwing the probe onto the implant during the implant stability check operation), to emit an ultrasonic wave which propagates inside the implant, to collect the reflected ultrasonic wave, in order to evaluate from a measurement of this reflected wave the integration of the implant into the bone.

[0006] Document WO 2019 / 201888 discloses a device using such a probe.

[0007] In the case where the probe is coupled to the implant by being screwed into the implant, it is important, for the reliability of the measurement of the reflected ultrasonic wave, that the screwing of the probe into the implant is carried out with precise control of the tightening torque at which the screwing was carried out.

[0008] As is known, this screwing can be carried out by a practitioner (typically a dental surgeon) with the aid of a torque wrench. Such a wrench is used manually by the practitioner, who engages the wrench with the probe head (said probe head having, for example, the shape of a bolt with a polygonal cross-section), and manually tightens the probe into the implant by turning the torque wrench.

[0009] In this case, the wrench is designed to stop transmitting its tightening torque to the probe head when the torque applied by the practitioner reaches a given torque value. It is this value that will determine the tightening of the screw.

[0010] The torque wrench thus allows a certain degree of control over the tightening of the implant. However, this control can be improved, and in particular its reproducibility (that is, the fact that the same tightening torque is obtained by repeating the operation of screwing probes into implants). This is an objective of the invention.

[0011] Another objective of the invention is to facilitate the operation of tightening the probe in the implant in the mouth of a patient. SUMMARY

[0012] To achieve this objective, according to an embodiment, a tool for screwing an ultrasonic probe into a dental implant which is fixed in the bone of the mouth of a patient is provided, the tool comprising a body which has a proximal part and a distal part, the proximal part of the body comprising a handle or gripping interface to allow a practitioner to grasp the body by hand in order to apply a rotational moment to it around a longitudinal axis of the body, the distal part of the body being integral with said proximal part, and comprising a deformable part adapted to be engaged with the head of the probe, said deformable part surrounding a central cavity which is centered on said longitudinal axis of the body.

[0013] Some preferred, but not limiting, aspects of this tool are as follows: • The deformable zone is capable of deforming to release the rotational connection around the longitudinal axis of the body between the probe head and the body when, with the distal part of the body positioned in a clamping position on the probe head, the rotational moment transmitted by said distal part of the body to the probe head exceeds a predetermined value, • said determined value is preferably between 3 and 9 N.cm, • the said determined value is 5 N.cm, • said deformable part comprises one or more deformable tabs which extend in the longitudinal direction of the body and each have an inner face that is adjacent to said central cavity, • the inner faces of the tabs which are turned towards the central cavity form an n-sided polygon, the number n of sides being between 2 and 12 and preferably equal to 6, • Each deformable tab of the deformable part is separated from each of its neighboring tabs by a respective groove, each tab being free in its distal part and attached to the body by its proximal part, • the body also includes a lug, a distal part of which protrudes into said central cavity along the direction of said longitudinal axis, and thus constitutes a stop along the direction of this axis, • said stop allows control of the position of the tool relative to the probe along the longitudinal direction and therefore of the depth, along the longitudinal direction of the tool axis, of the part of the probe head that is engaged in contact with the deformable part of the tool, • The body dimensions are as follows: • Height (h) of the protruding lug in the central cavity: between 0.1 mm and 4 mm, • Thickness (e) of the tabs in the radial direction: between 0.3 mm and 3 mm. • The body dimensions are as follows: • Height (h) of the protruding lug in the central cavity = 2 mm • Thickness (e) of the tabs in the radial direction = 1.25 mm, • The body dimensions are as follows: • Internal diameter (Dint) of the central cavity E = 6.35 mm, • The tool body material is a deformable plastic polymer, which is resistant to high temperatures to allow for autoclaving in clinical use. • The material of the tool body is PPSU (Polyphenylsulfone).

[0014] According to a second aspect, the invention also proposes an assembly for characterizing the stability of an implant in a patient's bone, comprising a tool according to one of the aspects mentioned above, and an ultrasonic probe intended to be screwed into the implant.

[0015] Preferred, but not limiting, aspects of such a set of characteristics for assessing the stability of an implant in a patient's bone are as follows: • said deformable part comprises n deformable tabs extending parallel to the longitudinal axis of the body and around this axis to form a ring of tabs around the central cavity, each deformable tab having an inner face which is adjacent to the central cavity and which is able to cooperate with one of the n faces of the polygonal head of the probe to establish the rotational link around the longitudinal axis of the body between the head of the probe and the body, • The difference in diameter between the internal diameter of the central cavity and the external diameter of the probe head is between 0 and 2 mm. BRIEF DESCRIPTION OF THE FIGURES

[0016] The aims, objects, features and advantages of the invention will become clearer from the detailed description of an embodiment thereof, which is illustrated by the following accompanying drawings in which:

[0017] [Fig. 1] Fig. 1 represents a medical device comprising a handpiece and an ultrasound probe, with a partial enlarged view showing the application of a connector of the handpiece onto the probe head,

[0018] [Fig.2] Fig.2 represents a dental implant fixed in the bone of a patient's mouth, an ultrasonic probe screwed into the implant, and a tightening tool according to a first embodiment of the invention,

[0019] [Fig.3A] [Fig.3A] is part of a set of figures 3A to 3E which represent the clamping tool illustrated in [Fig.2], in perspective view in an unassembled state ([Fig.3A]), and in assembled state in top view, bottom view, front elevation, and sectional view.

[0020] [Fig. 3B] Figure [Fig. 3B] shows the same clamping tool, in top view,

[0021] [Fig.3C] Fig.3C represents the same clamping tool, viewed from below,

[0022] [Fig.3D] Fig.3D represents the same clamping tool, in elevation,

[0023] [Fig. 3E] Fig. 3E represents the same clamping tool, in cross-sectional view along the plane AA defined on the [Fig.3D],

[0024] [Fig.4] [Fig.4] represents a clamping tool according to a second mode of realization of the invention,

[0025] [Fig.5A]

[0026] [Fig.5B] Figures 5A and 5B schematically represent test installations for measuring respectively the tightening torque of a torque wrench ([Fig.5A]), and the tightening torque of a tool according to the invention ([Fig.5B]).

[0027] [Fig.5C] [Fig.5C] shows the dimensions of a tool according to the invention according to the first embodiment illustrated in Figures 2 and 3.

[0028] The drawings are given by way of example and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate understanding of the invention and are not necessarily to scale with practical applications. DETAILED DESCRIPTION

[0029] Fig. 1 represents a device comprising a handle or handpiece P which includes a tip PL. This device also includes an ultrasonic probe S, which is screwed into an implant I. The implant I is fixed in the bone of the mouth of a patient.

[0030] The probe S is screwed into the implant, to measure its stability in the bone as explained below.

[0031] The handpiece contains means for generating an output signal (for example an electrical pulse), means for receiving and processing an input electrical signal, a memory for storing this input signal and a display P2 for displaying a result of the measurement produced by the processing means.

[0032] The handpiece tip includes a Pli connector which is connected to the means for generating an outgoing signal and to the means for receiving an incoming signal. This connector has a free distal end which can be brought into contact with the probe S.

[0033] The probe S includes means for transforming an electrical signal received from the handpiece connector into an ultrasonic signal, and for emitting this ultrasonic signal into the implant.

[0034] The probe S also includes means for collecting the ultrasound signal reflected by the implant, following the emission of an ultrasound signal emitted by the probe.

[0035] The connector is capable of receiving, upon contact with the probe, an incoming electrical signal that is representative of the reflected ultrasonic signal in response to the ultrasonic signal emitted by the probe, and of transmitting this electrical signal to the processing means. The processing means are capable of deducing from this incoming electrical signal a measurement of the implant's stability. The display P2 is capable of displaying this implant stability measurement.

[0036] The application of the PI 1 connector of the tip is illustrated in more detail in the box on the left side of the figure (on this enlarged view the Pli connector has the general shape of a ring).

[0037] Applying the Pli connector to the probe head activates the probe, causing it to emit an ultrasonic wave into the implant and to receive a signal representing the reflected ultrasonic wave. This signal is transmitted to the processing equipment, and at the end of the processing, the handpiece P displays a stability measurement result for the implant on the display P2.

[0038] Fig. 2 illustrates an implant I fixed in the bone of a patient's mouth, a probe S screwed into the implant to measure its stability in the bone, and an embodiment of a clamping tool 10 according to the invention.

[0039] The left part of this figure shows the three parts (implant, probe, and clamping tool) assembled in a position allowing the probe to be tightened into the implant with the clamping tool 10.

[0040] The right part of this figure shows more particularly the probe S (at the bottom of the right part of the figure), and the clamping tool 10 according to the invention (at the top of the right part of the figure).

[0041] The probe comprises a polygonal head SI which forms a bolt head, and a distal end S2 which has fastening means such as a thread, adapted to fix the probe in the implant (the implant having a complementary thread for this purpose). In [Fig. 2] the probe head is hexagonal.

[0042] The clamping tool 10 comprises a body 11 which has a proximal part 111 and a distal part 112, as well as a central lug (not visible in this figure) integral with the body.

[0043] In the embodiment illustrated in this figure, the body 11 includes a narrowing 110 between its distal and proximal parts. This notably minimizes the amount of material required to manufacture the body.

[0044] The proximal part 111 of the body includes a handle or gripping interface 1110 to allow a practitioner to grasp the body by hand in order to apply a rotational moment to it about a longitudinal axis A of the body.

[0045] In the figures, this gripping interface is polygonal, in particular octagonal. It may have a different shape. It is generally advantageous for this shape to be adapted to allow a user to position the tool on the probe head, and to manipulate the tool to apply a clamping torque to the probe head, directly by hand (i.e. without using a tightening wrench).

[0046] The tool according to the invention can, in its various embodiments, be manipulated directly by hand without requiring a tightening key. This is particularly advantageous in the confined space of a patient's mouth.

[0047] The distal part 112 of the body is configured to be positioned, as shown on the left side of this figure, on the probe head in the clamping position in which: • The longitudinal axis A of the body is aligned with the longitudinal axis A' of the probe, • and the probe head is made fixed to the body in rotation around the longitudinal axis of the body, by the complementary shape of the distal part 112 of the body and the shape of the probe head SI. More precisely, the distal part of the body surrounds the probe head and is able to rotate it around the longitudinal axis A.

[0048] The distal part of the body can thus be positioned in a clamping position on the probe head, and by applying a clamping torque to the body around the axis A as indicated by the arrow T, this clamping torque is transmitted to the probe head through the cooperation of the complementary shapes of the distal part of the body and the probe head.

[0049] When the tool is positioned on the probe head and manipulated to apply a clamping moment, this allows the probe head to rotate, in order to screw it into the implant.

[0050] The distal part 112 of the body comprises in the embodiments illustrated in the figures a peripheral ring C which surrounds a central cavity E. The central cavity E is centered on the axis A. The shape of this cavity is complementary to the shape of the probe head, so that the probe head can be housed, and fixed in rotation, in this cavity.

[0051] Thus, when the probe head is engaged and positioned in the cavity E, the form cooperation between the tool and the probe head allows the tool to transmit a tightening torque to the probe head.

[0052] Furthermore, the bottom of cavity E (said bottom being at the top of the cavity in the figures) acts as a stop for the probe head, allowing control of the tool's position relative to the probe along the longitudinal direction. This control allows control of the depth (along the longitudinal direction of axis A) of engagement of the probe head with the tool, and in particular with the deformable part of the tool.

[0053] The crown C includes a deformable part 1120 capable of deforming.

[0054] This deformable part is capable of deforming when the tightening torque applied to the probe by the tool reaches a so-called release value, this value being determined by the characteristics of the deformable part.

[0055] When this release value is reached and the deformation of the deformable part occurs, the rotational link between the probe head and the body is released (in other words: the rotation of the distal part of the body no longer causes the probe head to rotate).

[0056] Generally, this release value is preferably between 3 and 9 N.cm (Newton-centimeter). Particularly preferred, this release value is 5 N.cm.

[0057] In the embodiments illustrated in the figures, the deformable area 1120 includes deformable tabs 1121.

[0058] Each deformable tab 1121 extends in the longitudinal direction of the body and has an inner face which is adjacent to the central cavity and which is able to cooperate with one of the n faces of the polygonal head of the probe to establish the rotational link between the head of the probe and the body.

[0059] For a polygonal probe head with n facets, the number of tabs can be between 2 and n. In the embodiments illustrated in the figures, the number of tabs is n (i.e., the distal part of the tool body comprises as many deformable tabs as there are faces on the probe head, and in this case, the inner faces of the tabs that are turned towards the central cavity E form an n-sided polygon). Furthermore, in these embodiments, n = 6, and the tabs form a hexagon.

[0060] As illustrated in [Fig.2], each tongue 1121 of the crown is separated from each of its neighboring tongues by a respective groove 1122, each tongue being free in its distal part and attached to the body by its proximal part.

[0061] The body of the tool is made of a deformable material, to allow the deformation of the tabs 1121 when the tightening torque transmitted by the tool to the probe head reaches the release value.

[0062] Figures 3A to 3E show in more detail the tool 10, with the body 11 as well as the lug 12 which is clearly visible in particular on [Fig.3A].

[0063] View 3A shows the body and the lug side by side, the lug not being mounted in the body in this view. As can be seen, for example, in section AA of [Fig. 3E], which represents the assembled tool, to constitute the tool ready for use, the lug is fixedly assembled in the body, in a central recess 1111 that extends around the longitudinal axis A of the body. The lug is thus rigidly attached to the body.

[0064] The lug has a cylindrical proximal part 121 which is fixedly mounted in the recess 1111 - this is also visible on the top view 3B of the assembled tool.

[0065] The lug also has a distal part 122. When the lug is mounted in the body, this distal part 122 of the lug protrudes into the central cavity E along the direction of the longitudinal axis A, and thus constitutes a stop along the direction of this axis for the probe head when the latter is engaged in the central cavity E. The stop provided by this lug thus makes it possible to control the position of the tool relative to the probe along the longitudinal direction and therefore to control the depth, along the longitudinal direction of the axis of the tool, of the part of the probe head that is engaged in contact with the deformable part of the tool.

[0066] This distal part 122 of the lug can be, as shown in [Fig.3E] and also in [Fig.3E] which is a bottom view of the assembled tool, wider than the proximal part of the lug in order to present in the assembled position of the tool a rear face 1220 which allows the lug to be held in position in the body 11, even when the probe head comes to press along the longitudinal axis A on the stop of the distal part 122 of the lug.

[0067] This allows the probe head to be precisely maintained in the direction of the longitudinal axis A, when the tool is assembled on the probe. This control of the probe's insertion depth in the tool helps to control the tightening torque applied to the probe head by the tool.

[0068] To screw an ultrasonic probe S into an implant I in order to check the stability of the implant, using a tool according to the invention as shown for example in Figures 3 or 4, the screwing procedure is as follows: • The probe is lightly screwed into the implant by the practitioner using their finger, then the practitioner takes the tightening tool and forcefully inserts it onto the upper part of the probe. Alternatively, the tightening tool is inserted onto the probe beforehand, and then the practitioner manually inserts the assembly (probe and tightening tool) into the mouth. • The practitioner then rotates the tightening tool, holding it by the upper part, until the tightening torque he applies to this tool is reached. When the release value is reached, the tool's tabs will deform radially outwards (i.e., away from the longitudinal axis A), followed by a rotation of the tool relative to the probe head until the deformed tabs return to their original configuration against the probe head faces, pulled back towards axis A by their elasticity. This momentary release of the tool from the probe will also be audible, as a "click" sound emitted by the tabs returning to contact with the probe head faces. • To ensure proper tightening, the practitioner can then continue to rotate the tool by a number of degrees corresponding to one or more "clicks" (in the case of a hexagonal probe head cooperating with a six-tab tool: each new click corresponds to a 60-degree rotation of the tool relative to the probe head, and the additional rotation can thus, for example, be between 60 and 360 degrees, which amounts to 1 to 6 clicks).

[0069] The limitation of the tightening torque thus uses the deformation in spacing of the tabs as well as by the geometry of the cavity E and the deformable part 1120 of the crown.

[0070] The deformation in spacing of the tabs (and, more generally, of the deformable part of the distal part of the tool body) is caused by the radial stress directed outwards (away from the axis A) and applied on the internal faces of the tabs (and generally of the deformable part), by the parts of larger diameter of the probe head which constitute the edges of the polygonal probe head.

[0071] And this deformation is made possible by the mechanical properties of the material used to manufacture the body and its tabs 1121,

[0072] A “click” as mentioned above refers to the rapid elastic tightening of the tabs on the faces of the probe head when the rotation of the tool relative to the probe head is continued—actually resumed—after the release value has been reached. The click mentioned in this text should therefore be understood as a step in this resumption of rotation once the release value of the torque has been reached and then exceeded by the force applied to the tool by the practitioner, and when the complementary shapes of the probe head and the deformable part of the tool have faces separated by edges.

[0073] This resumption of rotation occurs in "steps" when the complementary shapes of the probe head (hexagonal in the examples illustrated in the figures), and the internal faces (i.e., those facing the central cavity E) of the The crown tongues have flat faces extending in a direction generally parallel to the longitudinal axis A and separated by edges.

[0074] These flat faces represent in fact regions of smaller diameter of the central cavity E (on the edges of the cavity), and also of the probe head (on the external faces of the probe head).

[0075] The material of the tool body is, in an embodiment which may reproduce the characteristics shown with reference to figures 2 to 5, PPSU (or Polyphenylsulfone).

[0076] Generally, the body material is a deformable plastic polymer that is resistant to high temperatures to allow autoclaving for clinical use. Preferably, this material should also be biocompatible.

[0077] The geometry of the central cavity E and that of the deformable portion of the body must allow the deformable portion to move apart in order to release the probe head from the tool body by rotation about the longitudinal axis A when a given tightening torque (called the "release torque") is reached. This release torque is preferably between 3 and 9 N.cm, and is particularly preferably 5 N.cm.

[0078] The dimensions of the central cavity E, which is delimited on its sides by the tabs and at its bottom by the central lug, are controlled. The height (along the longitudinal axis A) of the contact area between the tabs of the tool and the faces of the probe head is also controlled by the positioning of the probe relative to the stop.

[0079] This ensures reproducible positioning of the probe in the tool, and reproducibility of the axial and radial force exerted by the tool on the probe.

[0080] Thus, the tightening torque applied to the probe by the tool is reproducible, and the applicant has determined that this tightening torque depends in particular on three geometric parameters, once the tool body material is fixed. These three geometric parameters are, as illustrated in [Fig. 5C]: • the radial thickness e of the tabs, • the distance Dint between two inner faces of two opposite tabs, and • the height h which is the distance, along the longitudinal axis A, from the part of the central lug which protrudes into the central cavity E.

[0081] Fig. 4 shows a second embodiment of the tool body, in which the only modification compared to the first embodiment is that the body does not have a narrowing between its distal and proximal parts.

[0082] In this variant the body and the lug form a single piece of material, and therefore do not require assembly.

[0083] Section B-Ben, upper right of the figure, which is a cross-section as defined in the elevation view of the upper left of the figure, thus comprises the following parts which follow one another from the proximal end to the distal end of the tool: • A proximal part whose height (always along the longitudinal direction) is in this example 4 mm - generally this height is preferably between 2 and 10 mm. • A central part (along the longitudinal axis) whose height is 3.8 mm in this example - generally this height is preferably between 1 and 10 mm. • A transition section with a width and a height of 0.68 mm in this example – generally, this height is preferably between 0.1 and 3 mm. This transition section forms a shoulder cone with a 45-degree angle to the longitudinal axis, and its length along the direction of the cone surface visible in this section is 0.95 mm. • A deformable distal portion, the height of which in this example is 5.35 mm, the legs of this deformable portion having a height of 5 mm - generally this height is preferably between 2 and 10 mm.

[0084] A lug also protrudes 2 mm (along the longitudinal direction) into the central cavity.

[0085] The bottom view of this same figure shows the following diameters: • Diameter of the rounded tip of the lug = 1 mm • Diameter of the base of the spur (i.e., the proximal part of the tip of the lug) = 3.5 mm • Internal diameter of the ring formed by the tabs = 6.35 mm • External diameter of the crown formed by the tabs = 8.85 mm.

[0086] Finally, the top view which is below the bottom view shows a distance of 6.5 mm between two opposite edges of the proximal part of the tool, this proximal part being here octagonal with eight faces and eight edges distributed around the longitudinal axis.

[0087] This embodiment is also identical to the first embodiment, and its operation and performance are the same.

[0088] Tests were carried out to characterize the influence of the three geometric parameters mentioned above on the performance of the tool, and more particularly on the reproducibility of the tightening torque obtained (which corresponds to the release value of this torque).

[0089] The tests were carried out with a tool whose body was made of PPSU (Polyphenylsulfone).

[0090] They were carried out on the same probe, the hexagonal head of which had the following dimensions: • Distance between two opposite faces: 6.20 mm • Distance between two opposite edges: 6.70 mm • Height of the faces (along the longitudinal axis A): 3.00 mm • Width of the faces (perpendicular to the longitudinal axis A): 2.54 mm

[0091] For screwing an ultrasonic probe into a dental implant, the aim is to obtain a tightening torque preferably between 3 and 9 N.cm, and particularly preferably a tightening torque of 5 N.cm.

[0092] For these tests, as illustrated in Figures 5A and 5B, the distal part of the probe S was fixedly mounted in a torque meter M allowing the torque applied to the probe to be measured, the torque meter being mounted on a fixed frame (not visible in the figures).

[0093] The tests consisted of two measurement campaigns.

[0094] A first measurement campaign, the device of which is illustrated in [Fig.5A], was carried out by measuring the value of the release of the torque applied to the head of the probe by a torque wrench D with hexagonal head and of the type “Torque ratchet, Josef Ganter, torque range 10-70 Ncm, No. 1000701”.

[0095] In this first measurement campaign, measurements of the release value of the moment (value of the tightening moment applied by the key to the head of the probe, at which the key no longer causes the probe to rotate, when this tightening moment is progressively increased) were carried out for four series of twenty successive tightenings, by an operator handling a tightening key such as is usually used in a dental clinic.

[0096] The results of these series of measurements had a standard deviation of 0.64 N.cm

[0097] A second measurement campaign, the device of which is illustrated in [Fig. 5B], was carried out by measuring the release value of the torque applied to the probe head by a tool 10 according to the invention, made of PPSU. This tool had the geometry of the tool illustrated in Figures 2 and 3 - its crown was therefore made up of six deformable tabs forming a hexagon.

[0098] The dimensions of this tool, based on the geometric parameters illustrated in [Fig. 5C], were as follows: • Height h of the protruding lug in the central cavity = 2 mm • Thickness e of the tabs in the radial direction = 1.25 mm • Internal diameter Dint of the central cavity E = 6.35 mm.

[0099] In general, the following dimensions were identified in the development of the invention as advantageous for use in screwing the probe into the implant in a controlled manner, with a tool having the geometry of [Fig. 5C], the tool being in particular able to be made of PPSU:

[0100] Height (h) of the protruding lug in the central cavity: between 0.1 mm and 4 mm,

[0101] Thickness ( e) of the tabs in the radial direction: between 0.3 mm and 3 mm.

[0102] During the development of the invention, it was observed that the difference in diameter between the internal diameter of the central cavity and the external diameter of the probe head can advantageously be between 0 and 2 mm. These diameters, in the case of a tool crown and probe head that are polygonal in shape, are measured between opposite faces of the polygon.

[0103] In this second measurement campaign, measurements of the release moment value (the value of the tightening moment applied by the wrench to the probe head, at which the wrench no longer causes the probe to rotate, when this tightening moment is progressively increased) were carried out for ten series of twenty successive tightenings, by an operator handling the tightening tool, each series being carried out with a different tool, all the tools having the same dimensions and being made of PPSU.

[0104] The results of these series of measurements had a standard deviation of 0.37 N.cm (Newton.centimeter).

[0105] We have therefore observed with the use of a tool according to the invention a very significant decrease in the standard deviation (and therefore in the variability) of the release value, compared to measurements carried out using a torque wrench.

[0106] This illustrates the improvement in reproducibility offered by the invention, and therefore the increase in the reliability of the stability measurement of an implant fixed in a bone.

[0107] The clamping tool can consist of two separate, assembled parts (body and lug), with the lug being press-fitted into a central recess in the body. This allows the body and lug to be manufactured separately and simplifies manufacturing operations (molding, machining, etc.). The body and lug are fixed together, with no degree of freedom possible between these two parts.

[0108] In one embodiment, it is possible to provide that the body and the lug are made of two different materials. The body must be able to deform and is preferably made of a material such as PPSU, whereas deformation of the lug is not required and this lug can therefore be made of a more rigid material than the material of the body.

[0109] By allowing direct hand operation, without the need for a tightening key, the invention simplifies the operation of checking the stability of an implant.

[0110] The invention also makes this control more economical by eliminating the need for a tightening key.

[0111] Furthermore, it has been shown that the invention makes it possible to increase the reproducibility of the tightening torque obtained. This makes it possible to increase the reliability of the stability control of an implant fixed in bone because the tightening torque influences the acoustic response of the implant.

[0112] The invention relates to a tool as described above. It also relates to an assembly for characterizing the stability of an implant in a patient's bone, comprising such a tool and an ultrasonic probe intended to be screwed into the implant. The invention further relates to a complete device comprising such an assembly and a handheld device as described with reference to the prior art, intended to operate with the tool and the probe.

[0113] The invention is not limited to the embodiments previously described and extends to all embodiments covered by the invention.

Claims

Demands

1. A tool for screwing an ultrasonic probe into a dental implant that is fixed in the bone of a patient's mouth, the tool comprising a body having a proximal portion (111) and a distal portion (112), the proximal portion (111) of the body comprising a handle or gripping interface (1110) to enable a practitioner to grasp the body by hand in order to apply a rotational moment about a longitudinal axis (A) of the body, the distal portion (112) of the body being integral with said proximal portion, and comprising a deformable portion (1120) capable of being engaged with the probe head, said deformable portion surrounding a central cavity (E) that is centered on said longitudinal axis of the body.

2. Tool according to the preceding claim, characterized in that the deformable area (1120) is capable of deforming to release the rotational connection around the longitudinal axis of the body between the probe head and the body when, the distal part of the body being positioned in clamping position on the probe head, the rotational moment transmitted by said distal part of the body to the probe head exceeds a determined value.

3. Tool according to the preceding claim, characterized in that said determined value is preferably between 3 and 9 N.cm.

4. Tool according to the preceding claim, characterized in that said determined value is 5 N.cm.

5. Tool according to any one of the preceding claims, characterized in that said deformable part (1120) comprises one or more deformable tabs (1121) which extend in the longitudinal direction of the body and which each have an inner face which is adjacent to said central cavity.

6. Tool according to the preceding claim, characterized in that the inner faces of the tabs which are turned towards the central cavity form an n-sided polygon, the number n of sides being between 2 and 12 and preferably being 6.

7. A tool according to one of the two preceding claims, characterized in that each deformable tab (1121) of the deformable part is separated from each of its neighboring tabs by a groove (1122) respective, each tongue being free in its distal part and attached to the body by its proximal part.

8. Tool according to any one of the preceding claims, characterized in that the body also includes a lug (12) a distal part of which (122) protrudes into said central cavity in the direction of said longitudinal axis, and thus constitutes a stop in the direction of this axis.

9. Tool according to the preceding claim, characterized in that said stop allows control of the position of the tool relative to the probe along the longitudinal direction and therefore of control of the depth, along the longitudinal direction of the axis of the tool, of the part of the probe head which is engaged in contact with the deformable part of the tool.

10. Tool according to any one of claims 5 to 7 taken in combination with the preceding claim, characterized in that the dimensions of the body are as follows: • Height (h) of the protruding lug in the central cavity: between 0.1 mm and 4 mm, • Thickness (e) of the tabs in the radial direction: between 0.3 mm and 3 mm.

11. Tool according to the preceding claim, characterized in that the dimensions of the body are as follows: • Height (h) of the protruding lug in the central cavity = 2 mm • Thickness (e) of the tabs in the radial direction = 1.25 mm.

12. Tool according to the preceding claim, characterized in that the dimensions of the body are as follows: • Internal diameter (Dint) of the central cavity E = 6.35 mm.

13. Tool according to any one of the preceding claims, characterized in that the material of the body of the tool is a deformable plastic polymer, which is resistant to high temperatures to allow passage in an autoclave in clinical use.

14. Tool according to the preceding claim, characterized in that the material of the tool body is PPSU (Polyphenylsulfone).

15. A set for characterizing the stability of an implant in a patient's bone comprising a tool according to one of the claims previous ones, and an ultrasonic probe intended to be screwed into the implant.

16. Assembly according to the preceding claim characterized in that said deformable part comprises n deformable tabs extending parallel to the longitudinal axis of the body and around this axis to form a ring of tabs around the central cavity, each deformable tab having an inner face which is adjacent to the central cavity and which is able to cooperate with one of the n faces of the polygonal head of the probe to establish the rotational link around the longitudinal axis of the body between the head of the probe and the body.

17. Assembly according to the preceding claim characterized in that the difference in diameter between the internal diameter of the central cavity, and the external diameter of the probe head, is between 0 and 2 mm.

Images