Machinable preform for coronary-radicular reconstruction, machinable element comprising such a preform, method for carrying out coronary-radicular reconstruction, and method for manufacturing a preform

Abstract

Machinable preform for crown-root reconstruction, machinable element comprising such a preform, method for performing crown-root reconstruction, and method for manufacturing a preform. The preform (1) for a dental prosthetic element comprises two opposing principal faces (2, 3) and first fibers (7) parallel to a first direction (Y) and connecting the two opposing principal faces (2, 3). Layers (20) of fibers are superimposed along the first direction (Y). The first fibers (7) include at least one reference fiber (8) formed in a different color from the other first fibers. The preform has different mechanical properties at its two ends in response to a load perpendicular to the first direction (Y). Figure for the abstract: Figure 1

Description

Title of the invention: MACHINABLE PREFORM FOR CORONO-RADICULAR RECONSTRUCTION, MACHINABLE ELEMENT COMPRISING SUCH A PREFORM, METHOD FOR PRODUCING A CORONO-RADICULAR RECONSTRUCTION AND METHOD FOR PRODUCING A PREFORM Technical field

[0001] The invention relates to a preform for forming a prosthetic element, a machinable element comprising such a preform, a method of manufacturing the preform and a method of carrying out a coronal-radicular reconstruction using the preform and a coronal-radicular reconstruction. Prior art

[0002] In dentistry, it is conventional to use prosthetic elements to perform treatments and in particular to perform dental reconstructions. It is common to use an inlay-core, an implant abutment or a dental crown which are monobloc elements, that is to say which form a single piece. These prosthetic elements are made from a single material or a single set of materials. It is known to use metal alloys for the manufacture of prosthetic elements. Generally, the metal alloys used are stainless steels, titanium or equivalent materials such as minerals. It is also possible to produce prosthetic elements in monolithic ceramics and in particular zirconia.Unfortunately, the materials presented above have a modulus of elasticity that is higher than that of dentin, which can lead to detachment between the dentin and the prosthetic element or to fracture of the dental root. Furthermore, the use of a prosthetic element in a hard, one-piece material makes dismantling the tooth dangerous when it is necessary to intervene by grinding the prosthetic element to access the apical canal areas. Such an intervention must be carried out when an infection occurs.

[0003] The prosthetic elements can be formed in different ways, for example by a lost wax casting technique in a prosthetics laboratory or by machining a preform made from a metal alloy, a composite material or a ceramic. The prosthetic element can be obtained from the preform following a computer-aided design operation (CAD CAM in French or CAD CAM in English for Computer-Aided Design and Computer-Aided Manufacturing).

[0004] Different configurations of prosthetic elements have been proposed and / or are used. Document FR2588181 proposes an endobuccal prosthesis made of composite material. This prosthesis is used for the formation of a post for abutments or an inlay for dental reconstruction, for example for a coronal-radicular reconstruction. The post is formed by bundles of fibers assembled in a resin matrix. These posts are conventionally made by pultrusion. With such a post, it is necessary to glue the abutment to the post, which creates an additional interface and therefore an increased risk of failure. The abutment fills the empty space left by the tooth to serve as support for the crown. Such a structure replaces a single-piece inlay core by providing a prosthetic element formed by two pieces.Another post made of fiber composite material is described in document EP0432001 which uses parallel and continuous fibers along the longitudinal axis of the post. However, these posts are manufactured on site with fibers arranged by hand in the dental canal which implies disparities between the achievements and immobilization of the patient during all the stages of production.

[0005] Document US 2002 / 086266 proposes producing a preform that will be machined by CAD / CAM in order to form a dental prosthetic element such as a crown, a post, an inlay or an onlay. The preform is formed by a composite material reinforced by fibers. The fibers can be of any size and possibly woven. They can also be flocked. Document WO2017 / 098096 describes the manufacture of an inlay core manufactured by CAD / CAM from a machinable disc. The inlay core is formed by unidirectional fibers embedded in a polymer matrix. Circular rods are manufactured by pultrusion. The rods are made of unidirectional fibers embedded in a polymer matrix. The rods are cut into sections and are positioned in circular cells of a support. The support is a standard circular disc in CAD / CAM.

[0006] Document WO2010 / 109496 describes the use of a composite material which is formed by strong fibers associated with a polymer matrix. The composite material is intended to form either a dental crown or a post. The mechanically strong fibers are woven or knitted together to form planar reinforcing layers superimposed and bonded together. It appears that the layers bonded together by through-threads can slide. The planar layers are bonded together by means of several transverse reinforcing elements. The transverse reinforcing elements can be interknitted with the planar reinforcing layers. The composite material is subjected to an etching step to form a prosthetic element. Subject of the invention

[0007] An object of the invention is to provide a method of manufacturing a prosthetic element which is easy to implement and which makes it possible to form a prosthetic element which provides better mechanical performance.

[0008] The method of manufacturing at least one machinable preform for a prosthetic element comprising the following steps: - providing a three-dimensional lattice formed by a plurality of fibers and a plurality of attachment points, each fiber of the plurality of fibers comprising at least one attachment point with another fiber of the plurality of fibers so that the lattice retains its shape when subjected to a first stress value, the lattice defining a porous structure, the plurality of fibers comprising a plurality of first fibers arranged parallel to each other and oriented in a first direction, - fill the lattice with a first resin, the first resin applying the first stress to the lattice, - polymerize the first resin.

[0009] The method is remarkable in that the lattice forms at least two distinct zones arranged successively in the first direction and has different mechanical properties in response to a first stress perpendicular to the first direction.

[0010] In one embodiment, the plurality of attachment points is formed by a weld between two fibers, a brazing between two fibers, a node between two fibers, an attachment between two fibers by means of a second resin in the polymerized state.

[0011] Preferably, the method successively comprises the installation of the plurality of first fibers on a support, the first fibers being parallel to each other and the production of the other fibers of the plurality of fibers to form the lattice.

[0012] Advantageously, the lattice is formed by a single piece by means of an additive manufacturing process or by a subtractive manufacturing process.

[0013] In another embodiment, the plurality of fibers includes a reference fiber having a different color from the first fibers and the first resin, the reference fiber being parallel to the first fibers.

[0014] In a preferred configuration, the lattice forms at least a central portion, an intermediate portion and a peripheral portion, the intermediate portion surrounding the central portion and separating the central portion and the peripheral portion, the volume content of first fibers in the central portion being greater than the volume content of first fibers in the intermediate portion, itself greater than the volume content of first fibers in the peripheral portion.

[0015] It is also to be provided, in the central portion, that the volume content of first fibers is greater than the total volume content of the other fibers of the plurality of fibers.

[0016] Advantageously, the first fibers extend continuously from a first face to a second opposite face, the first face and the second face being opposite in the first direction.

[0017] In another configuration, the first resin has a Young's modulus lower than the Young's modulus of the lattice in the first direction and in a direction perpendicular to the first direction.

[0018] Preferably, the method further comprises forming at least one mark on the at least one lateral face of the machinable preform at the interface between two distinct zones of the at least two distinct zones.

[0019] In an advantageous embodiment, the plurality of fibers comprises second fibers extending perpendicular to the first direction in the form of a plurality of sheets of second fibers.

[0020] It is preferable to provide that each first fiber is attached to at least one of the plurality of sheets by an attachment point of the plurality of attachment points.

[0021] In a particular configuration, the at least two distinct zones are three zones arranged consecutively in the first direction. The three zones are distinguished from each other by at least one of the following parameters: - the volume percentage of second fibers, - the distance between two successive layers of second fibers, - the reinforcement of the second fiber layers when the layers are woven, - the chemical composition of the second fibers forming the layers of second fibers, - the orientation of the warp and weft fibers when the layers of second fibers are woven layers.

[0022] It is also advantageous to consider a method which comprises at least the following steps: - provide an impression of a tooth to be repaired, - calculate the dimensions of three zones arranged successively in the first direction and representative of a root anchor, a pulp box and a coronal reconstruction, - define the dimensions of the central portion perpendicular to the first direction, the dimensions of the central portion being chosen to be greater than the dimensions of the root anchoring zone perpendicular to the first direction - define the dimensions of the second fiber layers so as to extend beyond the dimensions of the root anchoring zone, the pulp box zone and the coronal reconstruction zone perpendicular to the first direction and define the configurations of the fiber sheets along the first direction to define the at least three zones, - form the three-dimensional lattice.

[0023] Preferably, the method comprises the manufacture of a plurality of machinable preforms rigidly connected to each other in the form of a support, the preforms of the plurality of machinable preforms being mechanically connected to each other at least by the first polymerized resin.

[0024] Advantageously, the preforms of the plurality of machinable preforms are mechanically connected to each other by fibers of the plurality of fibers with the exception of the first fibers.

[0025] It is also interesting to provide a step of singulating each of the machinable preforms by etching the support.

[0026] The invention also relates to a machinable preform facilitating the production of a prosthetic element and ensuring better mechanical behavior with respect to dentin in comparison with the machinable preforms of the prior art. To this end, the machinable preform for a dental prosthetic element comprises a three-dimensional lattice embedded in a first resin in the polymerized state. The three-dimensional lattice is formed by a plurality of fibers and a plurality of attachment points, each fiber of the plurality of fibers comprising at least one attachment point with another fiber of the plurality of fibers. The plurality of fibers comprises a plurality of first fibers arranged parallel to each other and oriented in a first direction, the plurality of attachment points having an interface with the first resin. The first fibers continuously connect two opposite faces in the first direction.The lattice forms at least two distinct zones arranged successively in the first direction and having different mechanical properties in response to a first stress perpendicular to the first direction.

[0027] Advantageously, the lattice forms three zones arranged consecutively in the first direction.

[0028] The invention also relates to a method for manufacturing a dental prosthetic element which is easy to implement and which makes it possible to form a prosthetic element better adapted to the differences in mechanical strength required between root anchoring and coronary reconstruction.

[0029] This problem is being solved by means of a method for manufacturing a dental prosthetic element comprising at least the following steps: - provide a machinable preform according to the previous configurations, - provide an impression of a tooth to be repaired, - engrave the machinable preform to reproduce the dimensions of the impression of the tooth to be repaired and define at least one root anchor, and a reconstruction coronary, from a root anchoring zone and a coronary reconstruction zone respectively.

[0030] The invention relates to a method for producing a coronal-radicular restoration which is easy to implement and which forms a coronal-radicular restoration mechanically better adapted to the dental wall. The method for producing a coronal-radicular restoration comprises the following steps: - provide a prosthetic element according to the preceding claim, - installing the prosthetic element in a dental canal of a laboratory model.

[0031] The invention also relates to a coronal-radicular restoration which is better adapted to the dental wall. This problem tends to be solved by means of a coronal-radicular restoration of a laboratory model, in which the prosthetic element comprises: - a three-dimensional lattice embedded in a first resin in the polymerized state, the three-dimensional lattice being formed by a plurality of fibers and a plurality of attachment points, each fiber of the plurality of fibers comprising at least one attachment point with another fiber of the plurality of fibers, the plurality of fibers comprising a plurality of first fibers arranged parallel to each other and oriented in a first direction, the plurality of attachment points (6) having an interface with the first resin.

[0032] The first fibers continuously connect two opposite faces of the prosthetic element from a root anchor to a coronal reconstruction in the first direction. The mesh has different mechanical properties between the root zone and the prosthetic reconstruction zone arranged successively in a first direction. The different mechanical properties are in response to a first stress perpendicular to the first direction. Summary description of the drawings

[0033] Other advantages and characteristics will emerge more clearly from the following description of particular embodiments and implementations of the invention given as non-limiting examples and represented in the appended drawings, in which:

[0034] [Fig-1] [Fig.l] schematically represents a preform according to the invention

[0035] [Fig.2] [Fig.2] schematically represents a form of pro element thetic to be machined in a preform according to the invention;

[0036] [Fig.3] [Fig.3] schematically represents a prosthetic element made from from a preform according to the invention;

[0037] [Fig.4] [Fig.4] schematically illustrates a coronal reconstruction dicular using a prosthetic element according to the invention;

[0038] [Fig.5] [Fig.5] illustrates, schematically, another embodiment of a preform according to the invention;

[0039] [Fig.6] [Fig.6] illustrates, in a schematic manner, yet another mode of rea preparation of a preform according to the invention;

[0040] [Fig.7] [Fig.7] schematically illustrates a machinable element grouping a plurality of preforms according to the invention;

[0041] [Fig.8] [Fig.8] schematically illustrates a machinable element grouping a plurality of preforms according to the invention, the constituent elements of which have been partially pooled. Description of the embodiments

[0042] [Fig.l] represents a preform 1 which is a machinable preform intended to cooperate with a computer-aided manufacturing machining device to form a dental prosthetic element and preferably a prosthetic element for a dental restoration. The preform 1 is a three-dimensional element which has a first main face 2, a second main face 3 and at least one lateral face 4 which connects the first and second opposite main faces 2 and 3. The preform 1 is intended to be machined so as to define a prosthetic element which will be used in a dental restoration, for example a dental restoration of a laboratory model.

[0043] The preform 1 is a composite block which comprises a first resin 5 which is associated with fibers. The machinable preform 1 comprises a three-dimensional lattice embedded in a first resin 5 in the polymerized state. The three-dimensional lattice is formed by a plurality of fibers and by a plurality of attachment points 6 between the fibers. An attachment point 6 is an attachment point between at least two fibers having different orientations such that the at least two fibers are mounted fixed relative to each other. Each fiber of the plurality of fibers comprises at least one attachment point 6 with another fiber of the plurality of fibers. The first resin 5 has a Young's modulus lower than the Young's modulus of the lattice in the first direction Y and in a direction perpendicular to the first direction Y.

[0044] The plurality of fibers comprises a plurality of first fibers 7 which are arranged parallel to each other and oriented in a first direction Y. The plurality of fixing points 6 has an interface with the first resin 5. The plurality of fixing points 6 ensures the mechanical strength of the mesh in addition to the first resin 5. The first fibers 7 continuously connect the two opposite faces 2, 3 of the machinable preform 1 in the first direction Y. The mesh forms at least two distinct zones arranged successively in the first direction Y. The two distinct zones have different mechanical properties in response to a first stress perpendicular to the first direction Y. After adding the first resin 5, the machinable preform 1 comprises at least two distinct zones, preferably three or at least three distinct zones 8, 9 and 10 arranged successively in the first direction Y.

[0045] The machinable preform 1 is formed by several sets of fibers which are oriented in different directions. The orientation of a fiber is defined by its longitudinal axis, the axis of its largest dimension. The machinable preform 1 is anisotropic. It has different mechanical characteristics, for example a Young's modulus, in the first direction Y and in a direction perpendicular to the first direction Y. The machinable preform 1 also has different mechanical characteristics, for example a Young's modulus, at each of its ends in the first direction Y when a stress is exerted in a direction perpendicular to the first direction Y.

[0046] In a particular embodiment, the first fibers 7 may be twisted fibers. In a preferred embodiment, the first fibers 7 have a maximum diameter of less than 0.45 mm and are advantageously unidirectional fibers. The first fibers 7 used may be glass fibers and for example E, R, S, AR and XRO fibers. It is also possible to use silica fibers. Ceramic fibers, boron fibers, silicon carbide fibers, carbon fibers are also usable. In general, the fibers may be mineral, organic and / or natural and / or metallic. It is also possible to use hybrid fibers, for example Zr-Ti fibers. The first fibers 7 may be formed by fibers made of ethylene, polyetheretherketone (PEEK) or polyamide. In general, the first fibers 7 are biocompatible fibers.It can also be fibers obtained using an additive manufacturing process, for example metal-ceramic or metal-zirconia hybrid fibers, in particular titanium-zirconium or metal-ceramic material fibers.

[0047] The machinable preform 1 does not have the same mechanical properties at its two ends, which makes it possible to better adapt the machinable preform 1 to the differences in stresses which exist in the dental canal and in the coronal part. The machinable preform 1 being inhomogeneous along the first direction Y, it has one end intended to form a coronal portion and one end intended to form a root anchor.

[0048] In order to further adapt the machinable preform to the needs of a dental prosthetic element, for example a coronal-radicular reconstruction, the machinable preform 1 comprises three or at least three zones 8, 9 and 10 mounted successively in the first direction Y. The different zones are distinguished from each other by different mechanical characteristics in response to a perpendicular stress. dicular to the first direction Y. Preferably, the mechanical differences correspond to deviations of at least 10% to distinguish a chosen mechanical difference and a manufacturing hazard.

[0049] The three zones 8, 9 and 10 of the preform 1 are intended to form respectively, after machining, a prosthetic element 14 which has a root anchor 11, a pulp box 12 and a coronal reconstruction 13 as illustrated in [Fig. 4]. The pulp box 12 separates the coronal reconstruction 13 and the root anchor 11. Advantageously, the pulp box 12 has a section greater than the section of the root anchor 11 and less than the section of the coronal reconstruction 13. The root anchor 11, the pulp box 12 and the coronal reconstruction 13 have different dimensions perpendicular to the Y direction as well as different mechanical properties.

[0050] The preform 1 has a root anchoring zone 8 which will be machined to form the root anchor 11, a pulp box zone 9 which will be machined to form the pulp box 12 and a coronal reconstruction zone 10 which will be machined to form the coronal reconstruction 13. The root anchor 11 is intended to ensure the mechanical connection between the prosthetic element 14 and the dentin wall 15 inside the dental canal 16 of the dental root 17.

[0051] To facilitate the use of the machinable preform 1 and in particular its etching to form a prosthetic element 14, it is advantageous to mark one end of the machinable preform 1, for example the end intended to form the root anchoring zone 8. At least one mark 18 is preferably made in a zone of the preform 1 which is intended to be etched, that is to say a sacrificial zone during the etching step to form the prosthetic element 14. It is advantageous for the mark(s) to indicate the interface between two zones 8 to 10 having different mechanical performances.

[0052] In order to functionalize the different zones 8 to 10 of the machinable preform 1 to adapt to the specific needs that exist and that are different from one end to the other of the prosthetic element 14, the fibers that form the lattice are arranged in different ways. The organization of the fibers at one end is different from the organization at the other end and it is even possible to define more zones having different fiber organizations to obtain different mechanical characteristics. The different zones 8 to 10 are mechanically connected at least by means of the first fibers 7 to ensure good transfer of forces along the first direction Y.

[0053] To form a machinable preform 1 whose mechanical characteristics differ between the two ends while being well controlled, it is advantageous to provide a lattice formed from the plurality of fibers.

[0054] The three-dimensional lattice is formed by a plurality of fibers and by a plurality of attachment points 6. Each fiber of the plurality of fibers has at least one attachment point 6 with another fiber of the plurality of fibers so that the lattice retains its shape when subjected to a first stress value. The lattice defines a porous structure. The fibers of the lattice are attached to each other with at least one attachment point 6 per fiber and preferably several attachment points 6 per fiber. It is advantageous if the first fibers 7 or at least a portion of the first fibers 7 have several attachment points with other fibers. By means of the plurality of attachment points, the lattice forms a rigid structure for the subsequent steps of the preform manufacturing method.

[0055] Conventionally, when a preform 1 is made with a set of fibers forming, for example, a woven or knitted material, the introduction of the resin results in a deformation of the stack of the different layers of fibers of the preform. The fiber sheets 20 deform, the fibers move inside the sheets 20 which deliberately have a certain laxity to allow the passage of the resin. Consequently, the structures initially formed to support mechanical characteristics deform and no longer meet the initial need.

[0056] In order to overcome this drawback, the lattice is configured to retain its shape when subjected to a first set of constraints. The first set of constraints corresponds to the set of constraints applied when filling the porous structure formed by the lattice with a first resin 5. Thus, when filling the lattice with the first resin 5 which applies the first constraint to the lattice, the lattice retains its shape and it retains the technical characteristics which were initially defined.

[0057] The first resin 5 is introduced into the mesh so that the first resin 5 completely fills the pores of the mesh. The first resin 5 is subsequently polymerized.

[0058] A machinable preform 1 is obtained with a lattice embedded in the first polymerized resin 5. The preform 1 is anisotropic in its characteristics between a stress in the first direction Y and a stress perpendicular to the first direction Y and there is a difference in mechanical performance for a stress perpendicular to the first direction Y between the two opposite ends of the preform.

[0059] The fixing points 6 between the fibers can be formed by any suitable means, for example by welding, by brazing, by a knot between fibers, by a second resin. It is possibly possible to use a prior fixing of the fibers by fixing points 6 in the material forming the first resin 5. This material is polymerized before embedding the mesh in a subsequent step. It is also possible to use a resin which is different from the first resin 5 and which advantageously has a Young's modulus greater than that of the first resin 5. The first resin 5 and the second resin are advantageously resins of the same family to facilitate the mechanical connection between the matrix in first resin 5 and the fixing points in second resin. The first resin 5 and the second resin can be differentiated by their filler content which modifies the mechanical properties.

[0060] The first resin 5 may be a single resin or a mixture of resins. The first resin 5 mechanically bonds the fibers together in addition to the attachment points. The first resin 5 may be a thermosetting resin or a thermoplastic resin. The first resin 5 may be a hybrid composite resin or a nanohybrid composite resin. The hybrid and nanohybrid composite resins have fillers that are less than 10 microns or less than 5 microns or less than 3 microns or less than 1 micron. The first resin 5 may be an organic, mineral, plant or organic resin. The first resin 5 forms the matrix of the preform 1. The matrix may be doped with micrometric and / or nanometric sized particles in order to modify its mechanical performance, its color, its crosslinking and / or other physicochemical properties. The matrix may also be doped with short fibers or whiskers / whiskers.

[0061] For the first resin 5, it is possible to use one or more thermosetting resins chosen from PMMA, TEGDMA, BISGMA, BDMA, HDDMA, UDMA, epoxy resins and polyester resins, for example vinylester. It is also possible to use thermoplastic resins chosen from PC, PGM and PU.

[0062] In a particular configuration, the preform 1 is solid. It is also advantageous to provide that the preform 1 is formed solely by the fibers and the resin matrix.

[0063] The plurality of fibers comprises the first fibers 7 and other fibers to form the lattice. The plurality of fibers may comprise second fibers 19 which extend at least in a direction perpendicular to the first direction Y to form the lattice. In a particular embodiment, the second fibers 19 are linked together in order to define several sheets 20 of second fibers 19. The sheets 20 of second fibers 19 define planes perpendicular to the first direction Y. Alternatively, it is possible to provide sheets 20 of second fibers 19 which are not planes perpendicular to the first direction Y. The fibers 19 forming a sheet 20 are preferably fixed together by fixing points 6. The sheet may be a woven, non-woven or knitted material. In an alternative embodiment, the lattice is without a sheet.Preferably, each first fiber 7 is fixed to at least one sheet 20 of the plurality of sheets 20 by a fixing point. 6 of the plurality of attachment points 6.

[0064] It is particularly advantageous to install the first fibers 7 parallel to each other on a support and then to fix the sheets 20 on the first fibers 7. The pre-assembled sheet is fixed on the first fibers 7. The monolithic sheet is fixed to the first fibers by the fixing points. In an alternative embodiment, the sheet 20 can be a monolithic element obtained by an additive method, of the three-dimensional printer type or subtractive by etching a substrate. In another alternative embodiment, the sheet 20 is woven, knitted or a non-woven structure.

[0065] The preform may also have fabric plies 20 and monolithic plies 20. Different types of attachment points can be used between the plies 20 and within a ply.

[0066] When the second fibers 19 are strictly perpendicular to the first direction Y, the plurality of fibers may also include third fibers 21 which have any orientation and which serve to fix the fibers together to form the lattice.

[0067] In a particular embodiment, the lattice is a monolithic element exclusively formed by an additive method, also known as 3D printing, or formed by a subtractive method by etching a substrate to define the different orientations of the fibers.

[0068] In another embodiment, the first fibers 7 are arranged on a support parallel to each other. The other fibers are installed so as to define the lattice. The fibers are placed in a three-dimensional manner, for example from the arms of one or more robots, and the physical connection between the fibers is made permanent by means of the fixing points. For example, the fibers are pre-impregnated and polymerization is carried out at the junction of the fibers to form a fixing point 6. The polymerization can be obtained by a thermal or electromagnetic stimulus. It is also possible to produce a welding or brazing point at the junction of the fibers. The support makes it possible to fix first fibers relative to each other during the preform formation step. After formation of the preform, the support can be removed without deforming the preform.The connections between the fibers ensure that the shape of the mesh is maintained when the resin is added to form the preform regardless of the presence or absence of the support.

[0069] In this way, step by step, the fiber mesh is mounted in three dimensions around the first fibers 7. This technique can be combined with the use of one or more sheets 20 in order to fix the position of the sheets 20 according to the first direction Y. By installing the fibers differently between the bottom of the mesh and the top of the mesh, it is possible to differentiate the characteristics of the preform 1 over the height of the preform 1, that is to say in the first direction Y.

[0070] The use of a method which successively comprises the installation of the plurality of first fibers 7 on a support then the production of the other fibers of the plurality of fibers to form the lattice is particularly advantageous because such a method is simple to implement and it is economical.

[0071] The lattice structure has a first Young's modulus along the first direction Y, a second Young's modulus along a second direction perpendicular to the first direction Y and a third Young's modulus along a third direction perpendicular to the first direction and to the second direction. The first fibers 7 and the second fibers 19 are chosen and arranged preferentially so that the first Young's modulus is different from the second and third Young's moduli and preferentially to be greater than the second and third Young's moduli. Advantageously, the first Young's modulus has a value of less than 35 GPa so as not to overstress the dentin or any other organ inside which the preform is intended to be inserted, for example during the chewing phases.

[0072] The preform 1 preferably has different mechanical performances depending on whether the machinable preform 1 is stressed at its center or at its periphery in the first direction Y. In a section plane perpendicular to the first direction Y, it is possible to divide the machinable preform 1 into a central portion 22 and a peripheral portion 24 or into a central portion 22, an intermediate portion 23 and a peripheral portion 24. The central portion 22 is inscribed inside the intermediate portion 23, itself inscribed inside the peripheral portion 24. The intermediate portion 23 defines a ring separating the central portion 22 and the peripheral portion 24. The intermediate portion 23 can have any internal shape and any external shape, but preferably circular shapes.The central portion 22, the intermediate portion 23 and the peripheral portion 24 extend from the first main face 2 to the second main face 3.

[0073] The central portion 22, the intermediate portion 23 and the peripheral portion 24 are distinguished from each other by different mechanical characteristics with respect to mechanical stresses in the first direction Y. It is possible to differentiate the central portion 22, the intermediate portion 23 and the peripheral portion 24 by different contents of first fibers 7. The content of first fibers 7 is preferentially decreasing from the central portion 22 to the peripheral portion 24. The peripheral portion may optionally be devoid of first fiber 7.

[0074] The plurality of fibers includes fibers that mechanically connect the portion central portion 22, the intermediate portion 23 and the peripheral portion 24, preferably second fibers 19.

[0075] In a preferred embodiment, in the central portion 22, the fibers are predominantly first fibers 7 and advantageously unidirectional fibers. In the central portion, the volume content of first fibers is greater than the total volume content of the other fibers of the plurality of fibers. The central portion acts mainly on the mechanical characteristics in the first direction Y. The first fibers 7 advantageously represent less than 50% of the volume of the central portion 22 and more preferably at least 80% of the volume of the central portion. In the central portion 22, the volume content of resin or resin and fillers is at least equal to 10%, preferably at least equal to 20% and less than 50%. Advantageously, the central portion 22 has an oval, circular or substantially circular section along the cutting plane perpendicular to the first direction Y.

[0076] Preferably, the central portion 22 extends over a distance at least equal to 1 mm in all directions perpendicular to the first direction Y. It is also advantageous to provide that the central portion 22 extends over a distance at most equal to 4 mm in all directions perpendicular to the first direction. By way of example, the central portion 22 contains or has a circular section whose diameter is between 1 mm and 4 mm, preferably between 1 mm and 2 mm.

[0077] In order to facilitate the machining of the preform 1, it is particularly advantageous to be able to identify a specific axis of the preform 1 which represents the first direction Y. The specific axis is advantageously formed by a reference fiber 25 oriented in the first direction Y or possibly offset by a known value relative to the first direction Y. The reference fiber 25 is advantageously a fiber different from the first fibers 7. The reference fiber 25 is advantageously a colored fiber whose color is different from the other fibers and from the matrix at least in the central portion 22. Thus, by observing the two opposite faces of the preform 1, the user is able to identify the reference fiber 25 and therefore to identify the first direction Y between the two opposite main faces 2 and 3. The reference fiber 25 can be fixed only to first fibers 7 or it can be fixed to other fibers.It is advantageous to place the reference fiber 25 in the center of the central portion 22. This makes it possible to identify the position of the central portion 22 in the machinable preform 1. It is then easier to machine the machinable preform 1 to form the prosthetic element and to have the maximum of the first fibers 7 which extend over the entire height of the prosthetic element to ensure good transfer of forces between the root anchor 11 and the coronary reconstruction 13.

[0078] It is also advantageous to provide that, in the intermediate portion 23, the fibers connecting the two opposite faces 2 and 3 are predominantly or exclusively first fibers 7 and more preferably unidirectional fibers. The first fibers 7 advantageously represent less than 80% of the volume of the intermediate portion 23, preferably between 50% and 80% of the volume of the intermediate portion 23. The volume content of resin or resin and dopants is at least equal to 10%, preferably at least equal to 20% and less than 50%.

[0079] When the intermediate portion 23 has a circular cross-section, it is advantageous to place the reference fiber 25 in the center of the intermediate portion 23. Thus, the user is able to identify the first direction Y and the center of the intermediate portion 23. The user can then machine the preform 1 without taking into account the planes defined by the two main faces 2 and 3, the lateral face 4 and possibly the hazards during the definition of the preform 1, for example when the two main faces are not parallel and / or are damaged. The use of the reference fiber 25 in association with a mark 18 on the external face of the preform to delimit at least one of the zones 8 to 10 in the Y direction allows a user to know the distribution of the fibers and therefore the orientation of the preform 1 and the position of the central portion 22.It is easier to machine the preform 1 according to the shape of the impression to be reproduced and to place the mechanical characteristics of the central portion 22 in a part of the prosthetic element 14 which extends over the entire height of the impression from the root anchor 11 to the coronal reconstruction 13.

[0080] It is particularly advantageous for the fiber content in the intermediate portion 23 to be lower than the fiber content in the central portion 22. It is also advantageous for the fiber content in the peripheral portion 24 to be lower than the fiber content in the intermediate portion 23. The fiber content is calculated by dividing the volume occupied by the fibers by the total volume of the central portion 22, the intermediate portion 23 or the peripheral portion 24 over the height of the preform 1.

[0081] Advantageously, the reference fiber 25 is made of a material which is more easily etched compared to the materials forming the matrix and compared to the materials forming the first fibers 7, the second fibers 19 and the third fibers 21. It is then easier to intervene on an infected apex by etching the reference fiber 25 with a reamer or any other equivalent device.

[0082] Advantageously, the volume percentage of first fibers 7 in the peripheral portion 24 is lower than the volume percentage of first fibers 7 in the central portion 22 and in the intermediate portion 23 by at least 20% by volume. In a particular embodiment, the volume proportion of second fibers 19 is greater than the volume proportion of first fibers in the peripheral portion 24 as illustrated in [Fig.6] and which can be obtained in the embodiment of [Fig.5].

[0083] In a preferred configuration, in the peripheral portion 24, the volume percentage of first fibers 7 decreases as one moves away from the center of the central portion 22. The decrease in the volume percentage may be linear with the distance from the center or the decrease may apply another rule. It is also possible to provide a volume percentage of first fibers 7 which is constant in the intermediate portion 23 or substantially constant in the intermediate portion 23 as one moves away from the center of the central portion 22. The same may be true in the peripheral portion 24.

[0084] Preferably, in the peripheral portion 24, the volume content of first fibers 7 is at least equal to 10% and preferably less than 50%. In the peripheral portion 24, the first fibers 7 are advantageously unidirectional fibers and they preferably represent between 10% and 50% of the volume of the peripheral portion 24.

[0085] As illustrated in Figures 1, 2, 5 and 6, in order to form a machinable preform 1 which is particularly well suited to the production of a dental prosthetic element, it is particularly advantageous to provide that the preform 1 has at least three consecutive zones 8 to 10 having different mechanical properties along the first direction Y as well as for at least the coronal reconstruction zone 10 and possibly for the pulp box zone 9 at least three portions 22 to 24 having different mechanical properties along a direction perpendicular to the direction Y.

[0086] It is advantageous to have a root anchor 11 which is formed or mainly formed or exclusively by the central portion 22. Preferably the volume of the root anchor is mainly formed by a bundle of first fibers 7. It is particularly advantageous to provide that the root anchor 11 is devoid of the peripheral portion 24 and possibly devoid of the intermediate portion 23, that is to say only formed by the central portion 22 or a part of the central portion 22.

[0087] In the root anchor 11, the other fibers and preferably the second fibers 19 are arranged so that the root anchor 11 has identical mechanical performances in the different directions perpendicular to the first direction Y or substantially identical. For example, the root anchor 11 has identical or substantially identical mechanical characteristics radially from the reference fiber 25 in all directions perpendicular to the first direction.

[0088] The first fibers 7 of the root anchor 11 are arranged so as to withstand tensile stresses in the first direction Y. Preferably, the volume proportion of first fibers 7 and other fibers is constant over the height of the root anchor 11. It is advantageous to form the root anchor zone with sheets 20 which have different orientations at least in the central portion 22 to homogenize the composition of the root anchor 11 radially of a first fiber 7 and of the reference fiber 25.

[0089] In the root anchoring zone 8 of the preform 1 and therefore in the root anchor 11, the first fibers 7 are predominantly unidirectional fibers oriented in a first direction Y in order to better withstand tensile stresses. It is therefore particularly advantageous to provide that the first direction Y will be the longitudinal direction of the prosthetic element 14 or substantially the longitudinal direction of the prosthetic element 14 so that the first fibers 7 are oriented in the longitudinal direction, for example a post or an inlay core. The first direction Y corresponds to the main direction of insertion of the prosthetic element 14.

[0090] The pulp box 12 makes it possible to embed the coronal-radicular reconstruction A in the pulp chamber 17. It has been observed that the pulp box 12 is subjected to a significant set of constraints in the form of peripheral tensile stresses perpendicular to the first direction Y. The peripheral tensile stresses are the cause of an accentuated deformation and delamination of the pulp box 12. It is therefore advantageous to form a pulp box 12 having mechanical performances different from the root anchor 11 to reduce the probability of delamination and thus avoid secondary fractures of the residual dental tissue and decohesion of the prosthetic elements.

[0091] In the pulp box zone 9 intended to form the pulp box 12, the volume percentage of other fibers is greater than the volume percentage of first fibers 7. The first fibers 7 ensure mechanical cohesion over the height of the pulp box 12. This configuration makes it possible to improve the resistance of this part of the preform 1 to peripheral tensile stresses perpendicular to the first direction Y. The pulp box 12 has a central portion 22 and at least part of the intermediate portion 23 or even the entire intermediate portion 23 and part of the peripheral portion.

[0092] A proportion of other fibers greater than the proportion of first fibers 7 is advantageously present in the peripheral portion 24, preferably in the intermediate portion 23.

[0093] It is particularly advantageous to use a pulp box area 9 whose fiber volume contains up to 80% other fibers and 20% first fibers 7.

[0094] The coronal reconstruction 12 is subjected, in the contact zone with the external edge of the root 17, to multidirectional tensile stresses and must in particular withstand the strongest peripheral stresses. In the coronal reconstruction zone 10 intended to form the coronal reconstruction 13, the volume percentage of other fibers, for example second fibers 19, is greater than the volume percentage of first fibers 7. The coronal reconstruction 13 comprises the central portion 22, the intermediate portion 23 and a part of the peripheral portion 24.

[0095] It is advantageous for the central portion 22 to be configured to adapt to the mechanical constraints of the root anchor 11, for the intermediate portion 23 to be adapted to the mechanical constraints of the pulp box 12 and for the peripheral portion 24 to be adapted to the mechanical constraints of the coronal reconstruction 13.

[0096] The ratio of the volume percentages between fibers connecting the two opposite faces 2 and 3 and the other fibers, for example the second fibers, is different between the coronal reconstruction 13, the pulp box 12 and the root anchor 11 in order to provide different mechanical properties and adapt the performance of the preform to the stresses to be supported.

[0097] Preferably, the central portion 22 is formed mainly, by volume, of first fibers 7 extending in the first direction Y. The central portion 22 preferably comprises between 75% and 85% by volume of fibers and between 15% and 25% by volume of resin. Preferably, the central portion 22 comprises 80% by volume of fibers and 20% by volume of resin.

[0098] It is also advantageous to provide that the volume proportion in sheets 20 in the intermediate portion 23 and of the peripheral portion 24 is preferably greater than the volume proportion in the central portion 22. Preferably greater by at least 10% by volume, even more preferably at least 30% by volume, or even equal to 50%, but preferably not more than 70% by volume.

[0099] It is possible to provide uniform plies 20 from one end to the other of the preform 1, for example woven, braided or knitted plies 20. The differentiation of the mechanical characteristics for the three successive zones of the first direction Y is carried out by modifying the materials used, the orientation of the plies 20 relative to each other, the reinforcement of the plies 20 and / or the distance between the plies 20. It is also possible to differentiate the mechanical performances between the intermediate portion 23 and the peripheral portion by means of the third fibers 21. The fibers in the ply 20 can be linked together in the form of a fabric, a knit or a braid. The plies 20 are superimposed in the first direction Y.

[0100] Alternatively, the sheets 20 are not uniform and they have differences between their central part and their peripheral part, for example the central portion of the sheet corresponding to the central portion 22 is identical for all the sheets 20 in order to impose the position of the first fibers 7. The central portion forms openings of a first size. Around the central portion, the organization of the fibers differs between the root anchor 11 and the coronal reconstruction 13 and preferentially between the root anchor 11, the pulp box 12 and the coronal reconstruction 13. The differentiation in the size of the openings outside the central portion between two consecutive sheets 20 makes it possible to modify the mechanical performances between the root anchor 11, the pulp box 12 and the coronal reconstruction 13.

[0101] As indicated above, the preform 1 defines at least three zones having different mechanical performances and, successive according to the first direction Y. The differentiation of the mechanical performances can be obtained by differentiating the characteristics of the plies 20. The differentiation of the mechanical characteristics can be obtained by differentiating at least one of the following parameters:

[0102] - the distance between two successive layers 20 in the first direction,

[0103] - the volume proportion in sheets 20 at least in the central portion 22,

[0104] - the volume proportion in sheets 20 at least in the intermediate portion 23,

[0105] - the volume proportion in sheets 20 at least in the peripheral portion 24,

[0106] - the intrinsic mechanical performances of the plies 20,

[0107] - the orientation of the sheets 20 relative to each other relative to a reference direction perpendicular to the first Y direction,

[0108] - the mechanical connections or welds installed between the fibers 19 and the first fibers 7.

[0109] The different plies 20 defining the zones of the preform 1 may be identical or different. It is particularly advantageous to use different plies 20, that is to say having different mechanical performances in order to be able to differentiate more easily the mechanical performances of the preform 1 in directions perpendicular to the first direction Y.

[0110] The different plies 20 are separated by a resin zone 5. The separation distance between the plies 20 may be different between two successive plies 20. By different distances, we mean at least two different distances of a value of at least 10%, preferably at least 20%. The difference in distance is a manufacturing choice and not a production hazard. Preferably, two consecutive plies 20 in the first direction Y are separated by a resin layer 5 whose thickness is advantageously at least equal to the thickness of the plies 20.

[0111] To define the different zones of the preform 1, the plies 20 can be divided into groups of plies 20 having different mechanical performances. The differences in mechanical performance can come from a different weaving between the groups of sheets 20 and / or by the use of different materials and / or by a different distribution of the fibers in the sheets 20 in each group.

[0112] In another embodiment of the preform not illustrated, the preform 1 has a section that increases from one end to the other, preferably continuously increasing. Advantageously, the evolution of the section of the preform 1 is carried out in stages. Each stage corresponds to a zone in the first direction Y having predefined characteristics to easily delimit each zone. The narrowest section corresponds to the root anchor. The root anchor may comprise only the central portion 22. The central portion 22 extends from one end to the other of the preform 1 in the first direction Y. The intermediate portion 23 may extend from one end to the other of the preform in the first direction Y. The intermediate portion is preferably present in the pulp box zone 9 and the coronal reconstruction zone 10.This embodiment is more complicated to produce or corresponds to a preliminary machining step to show the arrangements of the different zones in the preform 1.

[0113] In a particular embodiment illustrated in [Fig. 5], a central portion 22 is separated from the intermediate portion 23 by a first sheath 26 formed by one or more fibers which continuously go around the central portion 22, for example a sheet 20. The sheath can be limited to one of the multiple zones 8 to 10 in the first direction Y. It is advantageous for the first sheath 26 to extend over the entire height of the preform 1.

[0114] A second sheath 27 can be used to separate the intermediate portion 23 and the peripheral portion 24. The second sheath 27 advantageously extends over the entire height of one of the zones 8 to 10, preferably the pulp box zone 9 and / or the coronal reconstruction zone 10. It is advantageous for the second sheath 27 to be absent from the root anchoring zone 8. It is also possible to provide a third sheath 28 which is located at the periphery of the peripheral portion 24.

[0115] In a particular embodiment, several additional sheaths are arranged in the intermediate portion 23 and / or in the peripheral portion 24 to form the lattice.

[0116] Each sheath is separated from the adjacent sheath by first fibers 7 and by first resin 5. The sheaths advantageously have a circular or substantially circular section along a cutting plane perpendicular to the first direction Y. The sheaths can be woven or knitted. Depending on the desired configurations, the same preform may comprise only woven sheaths, only knitted sheaths or a mixture of woven sheaths and knitted sheaths.

[0117] The first fibers 7 arranged between the sheaths are advantageously in the form of a crown. In other words, it is advantageous to distribute uni form the fibers between the two sheaths. The fibers can be arranged in the form of individual fibers separated from each other by resin or in the form of an assembly of fibers, for example fiber-resin rods. The fibers can have a diameter between 1 mm and 0.5 mm.

[0118] Between two consecutive sheaths, the volume percentage of fibers is advantageously less than 80% and preferably greater than 30%. The resin forming the preform can be deposited by injection, infiltration, infusion or any other process allowing the production of a laminate preferably free of bubbles and resin gaps.

[0119] In another embodiment of the preform which is illustrated in [Fig.6], the central portion 22 extends from one end of the preform to the other in the first direction Y. Several different layers of fibers 19, 21 are wound around the central portion 22. The multiple layers of different fibers are distinguished from each other in their mechanical performances. They are also distinguished in their winding in order to be able to define an intermediate portion 23 and a peripheral portion 24. They are further distinguished in their extent in the first direction Y in order to be able to distinguish the root anchor 11, the pulp box 12 and the coronal reconstruction 12. In the illustrated embodiment, there is at least one fiber 19, 21 which extends in a shape which resembles a spiral to connect several first fibers and form at least a part of the mesh.

[0120] It is particularly advantageous, during the winding step, to install one or more fibers extending in the first direction Y. The fibers may be unpolymerized or partially polymerized pre-impregnated fibers.

[0121] The fibers are preferably unidirectional fibers, ribbons, simple woven sheaths, simple knitted sheaths. It is also possible to use hybrid sheaths with a core formed by a unidirectional fiber.

[0122] The first resin 5 of the preform 1 is polymerized before the machining step.

[0123] In addition to the reference fiber 25, the preform 1 advantageously has one or several markers 18 which are arranged on the at least one side wall 4. The marker(s) 18 are arranged so as to identify the separation between the different zones 8 to 10 arranged successively in the first direction Y.

[0124] The preform 1 is made by initially forming the lattice structure from the first and second fibers and then the first resin 5 is introduced to fill the holes. The preform 1 is intended to be machined in order to form a prosthetic element 14.

[0125] If necessary, the preform 1 is etched so as to define the height of the prosthetic element 14, i.e. the dimension along the first direction Y. The preform 1 is etched so as to define the dimensions of the prosthetic element perpendicular to the first direction Y. generally in the first direction Y and advantageously in the first direction Y. The preform is engraved from an imprint representing the prosthetic element 14 to be formed.

[0126] The preform advantageously has a height greater than the height of the impression. It is then advantageous to engrave a greater or lesser height of the root anchor compared to the engraving of the coronal zone in order to facilitate the adaptation of the shape of the prosthetic element 14 to that of the impression.

[0127] In a particular embodiment, the preform 1 is formed from the impression of the tooth to be repaired. The tooth is identified and the impression is taken so as to estimate the dimensions and the stress sets to be supported in each of the parts of the prosthetic element 14 intended to replace the tooth. The mesh is manufactured so as to respond to its multiple stress sets which are distributed over the height of the prosthetic element 14 as well as between its central portion 22 and its peripheral portion 24. Once the mesh is manufactured, the first resin 5 is added to a mold to form the machinable preform. The preform is then machined according to the impression of the tooth to be repaired so that the external shape of the preform adapts to that of the impression. The preform 1 can have any shape. The preform 1 can have a circular, square or rectangular section.

[0128] In another embodiment of a dental prosthetic element 14, the preform 1 is made in a standardized manner. The shape of the preform 1 is chosen so as to be compatible with the machining equipment. The dimensions of the root anchoring zone 8, the dimensions of the pulp box zone 9 and the dimensions of the coronal reconstruction zone 10 are defined independently of the associated impression and the prosthetic element 14 to be made on the basis of information generically representing teeth to be repaired. The lattices are made to represent standard configurations of teeth. The preforms can distinguish the type of tooth, for example, a molar, a premolar and a canine which induces differences in mechanical characteristics in the lattices.

[0129] It is advantageous to provide different preform models distinguished from each other by differences in the dimensions of the coronal portion perpendicular to the first direction Y. It is also advantageous to provide different models of preform 1 which are distinguished from each other by differences in the dimensions of the root portion 8 perpendicular to the first direction Y. By modulating the dimensions of the root anchoring zones 8 and coronal reconstruction 10, it is possible to best adapt the characteristics of the preform 1 to those of the reconstruction. The dimensions of the lattices perpendicular to the first direction Y are adapted accordingly.

[0130] The preform 1 is machined in order to define the shape of the root anchor 11 and define the shape of the coronary reconstruction 13. This machining makes it possible to define the dimensions of the prosthetic element in order to allow its insertion with the impression of a laboratory model.

[0131] The impression is taken, preferably by optical and computer means, for example with an impression camera, in order to determine the shape of the prosthetic element to be produced. Once the impression has been taken, the lateral dimensions of the prosthetic element are calculated and the preform can be machined. The lateral dimensions of the prosthetic element can be calculated by means of a computer, for example with instructions stored in a memory.

[0132] The mechanical characteristics of the preform being different along the first direction and perpendicular to the first direction, the positions of the central portion 22, of the root anchoring zone 8, of the pulp box zone 9 and of the coronal reconstruction zone 10 are determined in the preform before carrying out the machining independently of the distance separating the two opposite faces 2 and 3 and of the orientation of these two faces.

[0133] An impression of a tooth to be repaired is initially provided. This impression is scanned in a laboratory scanner. Alternatively, an impression calculated from data from a computer-aided design system is provided. Then, from the data representative of the impression, a step is carried out to calculate the dimensions of a root anchor 11, a pulp box 12 and a coronal reconstruction 13 in three dimensions. Preferably, a digitized three-dimensional image of the future reconstruction is provided.

[0134] In a particular embodiment, the root anchoring zone 8, the pulp box zone 9 and the coronal reconstruction zone 11 are aligned consecutively along the first direction Y on the preform 1. The three zones are aligned so as to make predefined markers coincide on the digitized image in the three dimensions of the preform 1.

[0135] The alignment of the three zones can be carried out by aligning the axes of the preform 1 with the axes of the image representative of the future reconstruction. Subsequently, it is advantageous to align a reference zone of the image representative of the reconstruction, for example the pulp box zone, to make it coincide with the equivalent zone from the mark(s) 18 of the machinable preform.

[0136] In a preferred embodiment, the position of the central portion 22 of the root part 11 inside the root anchoring zone 8 is calculated first. Once the central portion 22 of the root part 11 is placed in the preform, the positions of the other parts of the reconstruction are calculated.

[0137] When producing the preform 1, in a calculation step, a computer advantageously defines and aligns one or more reference points which will be used by the machining equipment for producing the root anchor 11 in the root anchor zone 8, as well as the shape of the pulp box 12 and the coronal reconstruction 13 in their respective zones of the preform 1.

[0138] An impression-taking step has been carried out and the information collected and / or calculated is used to carry out the machining of the preform 1. From the impression, the specialist defines the orientation of the first direction Y as well as the height of the different zones.

[0139] The reference mark 18 of the preform 1 is preferably used to determine the position and extent of the pulp box area. By means of the reference mark 18 and the reference fiber 25 of the preform 1, it is possible to define the position of the three-dimensional image of the reconstruction in the preform independently of the orientation of the external faces of the preform which will be machined. A set of machining data is provided to the machining equipment to engrave the prosthetic element in the preform 1. The machining order of the different parts of the reconstruction can vary according to the equipment and the needs.

[0140] The machining of the preform 1 can be used to form an inlay core, a dental post or an implant abutment. After machining at least a portion of the long unidirectional fibers of the central portion 22 extend from one end to the other of the prosthetic element which has been formed by machining.

[0141] The calculation steps can be carried out by a calculator, for example a computer.

[0142] As illustrated in [Fig.4], once the prosthetic element has been formed by machining, it can be introduced into the dental canal as illustrated in [Fig.4]. The coronal reconstruction rests on the dental wall above the pulp box, which makes it possible to create, for example, an inlay core. The coronal-radicular reconstruction can be without a crown.

[0143] Advantageously, the reference fiber 25 is made of a material which can be preferentially etched relative to the matrix material and the other first fibers 7. In a completed coronal-radicular reconstruction, it is possible, later, to preferentially etch the coronal-radicular reconstruction A so as to access an infected apex. The preferential etching can be done by means of a reamer using a material having a hardness lower than the hardness of the other first fibers 7 and the resin. This configuration does not exist in prosthetic elements made by means of machinable preforms.

[0144] Machining the preform to form a coronal-radicular reconstruction makes it possible to form a reconstruction whose three-dimensional shape is defined from the impression of the tooth to be repaired and / or from a calculated impression of the tooth to be replaced. The three-dimensional shape of the reconstruction is specific for adapt as best as possible to the dentin wall.

[0145] The machining defines the shape of the tooth and therefore the dimensions relative to the reference fiber 25 perpendicular to the first direction Y. The machining also defines the height of the prosthetic element 14 along the first direction Y as well as the height of the root anchor 11 and of the coronal reconstruction 13 by removing a part of the two opposite ends of the preform 1. By using preforms that are higher than conventional reconstructions, the same preform can be adapted to a large number of repair configurations.

[0146] By using the reference 18 present on the preform 1 and by indicating the characteristics of the preform 1, in particular the position of the interface between the pulp box and the root anchor and the position of the interface between the pulp box and the coronal reconstruction, the machining equipment is able to machine the preform to define its height as well as the height of the root anchor and the height of the coronal reconstruction.

[0147] [Fig.7] and 8 illustrate a machinable element which comprises several machinable preforms described previously. The manufacturing method allows a single preform to be produced but it also allows several preforms to be produced. Depending on the case, the preforms are identical or different.

[0148] The multiple machinable preforms are formed together so that the machinable element forms a monolithic element that contains the multiple preforms. The different lattices can be formed simultaneously or successively. A single step of adding the first resin 5 is preferably carried out. The multiple preforms are mechanically connected to each other by the first resin 5 so as to form a single-piece element that facilitates handling and avoids damaging the preform edges. In a particular embodiment, the preforms are mechanically connected by one or more fibers with the exception of the first fibers.

[0149] The machinable preforms are distinguished from each other by a step of etching the machinable element. Preferably, the etching device detects the presence of a reference fiber 25 representing the center of the preform 1 and it etches the machinable element to isolate the machinable preform.

[0150] When the preforms are formed by fixing the first fibers on a support before installing the other fibers forming the lattice, the support is preferably removed from the preform before carrying out the machining. When several preforms are produced on the same support, the support is preferably separated from the machinable system before singulating the multiple machinable preforms by cutting the machinable system.

[0151] It is advantageous that the first fibers 7 used in the central portion 22 are thinner than the first fibers 7 used in the intermediate portion 23, themselves thinner than the first fibers 7 used in the peripheral portion 24.

Claims

Claims

1. A method of manufacturing at least one machinable preform (1) for a prosthetic element (14) comprising the following steps: - providing a three-dimensional lattice formed by a plurality of fibers (7, 19, 21) and a plurality of attachment points (6), each fiber of the plurality of fibers (7, 19, 21) comprising at least one attachment point (6) with another fiber of the plurality of fibers (7, 19, 21) such that the three-dimensional lattice retains its shape when subjected to a first stress value, the three-dimensional lattice defining a porous structure, the plurality of fibers (7, 19, 21) comprising a plurality of first fibers (7) arranged parallel to each other and oriented in a first direction (Y), - filling the three-dimensional lattice with a first resin (5), the first resin (5) applying the first stress to the three-dimensional lattice, - polymerizing the first resin (5),the three-dimensional lattice forming at least two distinct zones (8, 9, 10) arranged successively in the first direction (Y) and having different mechanical properties in response to a first stress perpendicular to the first direction (Y), in which the three-dimensional lattice forms at least a central portion (22), an intermediate portion (23) and a peripheral portion (24), the intermediate portion (23) surrounding the central portion (22) and separating the central portion (22) and the peripheral portion (24), the volume content of first fibers (7) in the central portion (22) being greater than the volume content of first fibers (7) in the intermediate portion (23), itself greater than the volume content of first fibers (7) in the peripheral portion (24) so ​​that the central portion (22),the intermediate portion (23) and the peripheral portion (24) have different mechanical properties in a direction perpendicular to the first direction (Y).,

2. Method for manufacturing at least one machinable preform (1) according to claim 1 in which the plurality of fixing points (6) is formed by a weld between two fibers, a brazing between two fibers, a knot between two fibers, a fixing between two fibers by means of a second resin in the polymerized state.

3. Method for manufacturing at least one machinable preform (1) according to one of of claims 1 and 2 successively comprising the installation of the plurality of first fibers (7) on a support, the first fibers (7) being parallel to each other and the production of the other fibers of the plurality of fibers (7, 19, 21) to form the three-dimensional lattice.

4. A method of manufacturing at least one machinable preform (1) according to claim 1 wherein the three-dimensional lattice is formed by a single piece by means of an additive manufacturing method or by a subtractive manufacturing method.

5. A method of manufacturing at least one machinable preform (1) according to any one of the preceding claims wherein the plurality of fibers (7, 19, 21) comprises a reference fiber (25) having a different color from the first fibers (7) and the first resin (5), the reference fiber (25) being parallel to the first fibers (7).

6. Method for manufacturing at least one machinable preform (1) according to the preceding claim wherein, in the central portion (22), the volume content of first fibers (7) is greater than the total volume content of the other fibers of the plurality of fibers (7, 19, 21).

7. Method of manufacturing at least one machinable preform (1) according to any one of the preceding claims in which the first fibers (7) extend continuously from a first face to a second opposite face, the first face and the second face being opposite in the first direction (Y).

8. Method for manufacturing at least one machinable preform (1) according to any one of the preceding claims in which the first resin (5) has a Young's modulus lower than the Young's modulus of the three-dimensional lattice in the first direction (Y) and in a direction perpendicular to the first direction.

9. Method for manufacturing at least one machinable preform (1) according to any one of the preceding claims, further comprising forming at least one mark (18) on the at least one lateral face (4) of the machinable preform (1) at the interface between two distinct zones (8, 9, 10) of the at least two distinct zones (8, 9, 10).

10. A method of manufacturing at least one machinable preform (1) according to any one of the preceding claims wherein the plurality of fibers (7, 19, 21) comprises second fibers (19) extending perpendicular to the first direction (Y) in the form of a plurality of sheets (20) of second fibers (19).

11. Method for manufacturing at least one machinable preform (1) according to the re-

12.

13.

14. claim 10 wherein each first fiber (7) is attached to at least one web (20) of the plurality of webs (20) by an attachment point (6) of the plurality of attachment points (6). Method for manufacturing at least one machinable preform (1) according to one of claims 10 and 11 in which the at least two distinct zones (8, 9, 10) are three zones arranged consecutively in the first direction (Y) and in which the three zones (8, 9, 10) are distinguished from each other by at least one of the following parameters: - the volume percentage of second fibers (19), - the distance between two successive layers (20) of second fibers (9), - the reinforcement of the layers (20) of second fibers (9) when the layers (20) are woven, - the chemical composition of the second fibers (19) forming the sheets (20) of second fibers (19), - the orientation of the warp and weft fibers when the sheets (20) of second fibers (19) are woven sheets (20). Method for manufacturing at least one machinable preform (1) according to any one of the preceding claims comprising at least the following steps: - provide an impression of a tooth to be repaired, - calculate the dimensions of three zones (8, 9, 10) arranged successively in the first direction (Y) and representative of a root anchor (11), a pulp box (12) and a coronal reconstruction (13), - defining the dimensions of the central portion (22) perpendicular to the first direction (Y), the dimensions of the central portion (22) being chosen to be greater than the dimensions of the root anchoring zone (10) perpendicular to the first direction (Y), - defining the dimensions of the sheets (20) of second fibers (19) so as to extend beyond the dimensions of the root anchoring zone (8), the pulp box zone (9) and the coronal reconstruction zone (10) perpendicular to the first direction (Y) and defining the configurations of the sheets (20) of fibers (19) along the first direction (Y) to define the at least three zones (8, 9, 10), - forming the three-dimensional lattice. A method of manufacturing at least one machinable preform (1) according to any one of the preceding claims comprising the manufacture of a plurality of machinable preforms (1) rigidly connected together they in the form of a support, the preforms (1) of the plurality of machinable preforms (1) being mechanically connected to each other at least by the first polymerized resin (5).

15. Method for manufacturing at least one machinable preform (1) according to the preceding claim in which the preforms (1) of the plurality of machinable preforms (1) are mechanically connected to each other by fibers of the plurality of fibers (19, 21) with the exception of the first fibers (7).

16. Method for manufacturing at least one machinable preform (1) according to claims 14 or 15 comprising a step of singulating each of the machinable preforms (1) by etching the support.

17. Machinable preform (1) comprising a three-dimensional lattice embedded in a first resin (5) in the polymerized state, the three-dimensional lattice being formed by a plurality of fibers (7, 19, 21) and a plurality of attachment points (6), each fiber of the plurality of fibers (7, 19, 21) comprising at least one attachment point (6) with another fiber of the plurality of fibers (7, 19, 21), the plurality of fibers (7, 19, 21) comprising a plurality of first fibers (7) arranged parallel to each other and oriented in a first direction (Y), the plurality of attachment points (6) having an interface with the first resin (5), in which the first fibers (7) continuously connect two opposite faces (2, 3) in the first direction (Y), and in which the lattice forms at least two zones (8, 9,10) distinct ones arranged successively in the first direction (Y) and having different mechanical properties in response to a first stress perpendicular to the first direction (Y), and in which the three-dimensional lattice forms at least a central portion (22), an intermediate portion (23) and a peripheral portion (24), the intermediate portion (23) surrounding the central portion (22) and separating the central portion (22) and the peripheral portion (24), the volume content of first fibers (7) in the central portion (22) being greater than the volume content of first fibers (7) in the intermediate portion (23), itself greater than the volume content of first fibers (7) in the peripheral portion (24) so ​​that the central portion (22), the intermediate portion (23) and the peripheral portion (24) have different mechanical properties in a direction perpendicular to the first direction (Y).,

18. Machinable preform (1) according to the preceding claim in which the lattice forms three zones (8, 9 10) arranged consecutively in the first direction (Y).

Images