METHOD FOR DESIGNING A PROSTHETIC ELEMENT

Abstract

A disclosed method for designing a prosthetic element is executable prior to a cutting of a tooth of a patient for placing the prosthetic element.

Claims

1. A method for designing a prosthetic element comprising the following steps: (i) providing a first computer file comprising: an intra-oral three-dimensional representation of a dentition comprising at least one tooth to be restored by means of said prosthetic element; and a radiographic image of said dentition; identifying common reference axes on said intra-oral three-dimensional representation and on said radiographic image; and comparing said intra-oral three-dimensional representation with said radiographic image, this comparison sub-step comprising an overlay of said common reference axes; (ii) determining a three-dimensional representation of an extrados of said prosthetic element on the basis of said first computer file; (iii) determining technical parameters comprising at least one of: a dental protocol; a type of dental preparation; and technical constraints, on the basis of said first computer file, at least one of said technical parameters being determined on the basis of the comparison sub-step of the step (i); (iv) generating a second computer file comprising a three-dimensional representation of a volumetric reduction of said at least one tooth on the basis of said technical parameters; (v) validating and/or modifying said second computer file; (vi) obtaining a three-dimensional representation of an intrados of said prosthetic element on the basis of said second validated and/or modified computer file; (vii) generating a third computer file comprising information relating to the three-dimensional representations of said extrados and intrados of said prosthetic element; and (viii) producing said prosthetic element on the basis of said third computer file.

2. The method according to claim 1, wherein the step (ii) comprises the following sub-steps: (ii.1) selecting a three-dimensional representation model of a model dentition from a database on the basis of said first computer file; (ii.2) selecting a zone of the three-dimensional representation model corresponding to a zone of the intra-oral three-dimensional representation corresponding to said at least one tooth; (ii.3) validating and/or modifying the zone of the three-dimensional representation model on the basis of said first computer file; and (ii.4) defining the three-dimensional representation of the extrados of said prosthetic element from the validated and/or modified zone of the three-dimensional representation model.

3. The method according to claim 1, wherein the step (iii) comprises the following sub-steps: (iii.1) determining a type of dental preparation on the basis of said first computer file; (iii.2) algorithmically generating a dental protocol on the basis of the type of dental preparation determined in the step (iii.1), said dental protocol consisting of a collection of numerical data to geometrically parameterise said three-dimensional representation of the volumetric reduction; and (iii.3) validating and/or modifying said dental protocol on the basis of the comparison sub-step of the step (i).

4. The method according to claim 3, wherein the sub-step (iii.1) comprises the following sub-steps: visualizing said intra-oral three-dimensional representation of a dentition; segmenting said intra-oral three-dimensional representation of a dentition so as to obtain an isolated three-dimensional representation of the at least one tooth; algorithmically generating vestibular, lingual, mesial, distal and occlusal faces of the at least one tooth by identifying a point on each of these faces at the isolated three-dimensional representation of the at least one tooth; modifying and/or validating boundaries of said vestibular, lingual, mesial, distal and occlusal faces of the at least one tooth by adding, moving and/or removing points of these faces on the isolated three-dimensional representation of the at least one tooth; and identifying a reference frame of at least one of said reference axes on the basis of the comparison sub-step of the step (i), the reference frame comprising an insertion axis of the at least one tooth.

5. The method according to claim 4, wherein the numerical data comprise: for each face among the vestibular, lingual, mesial and distal faces of said at least one tooth: a radius; and a height corresponding to a parameterisation of a transverse section of an elliptical fillet of the face along an elliptical arc of semi-major axis corresponding to said radius measured essentially perpendicularly to said insertion axis and of semi-minor axis corresponding to said height measured essentially parallel to said insertion axis; for each of the vestibular, lingual, mesial and distal faces of said at least one tooth, a first offset data corresponding to a displacement of each point of the face on the isolated three-dimensional representation of the at least one tooth towards the insertion axis; for the occlusal face of said at least one tooth a first offset data corresponding to a displacement of each point of the occlusal face on the isolated three-dimensional representation of the at least one tooth along the insertion axis; two percentages defining two zones consisting of marginal and middle zones of the at least one tooth on the isolated three-dimensional representation of the at least one tooth, each percentage corresponding to the ratio between a height of one zone and a height of both zones, these heights being measured essentially parallel to the insertion axis; and for each of said zones: a volumetric reduction orientation angle measured with respect to the insertion axis; and a minimum height.

6. The method according to claim 5, wherein the technical constraints comprise a minimum thickness of a material for the design of the prosthetic element, and in that the first offset data of the faces depend on this minimum thickness.

7. The method according to claim 5, wherein the step (iv) comprises a sub-step of algorithmic generation of a three-dimensional representation of a volumetric reduction of said at least one tooth, this sub-step comprising the following sub-steps: (iv.1) generating a marginal surface consisting of the elliptical fillets of the vestibular, lingual, mesial and distal faces of said at least one tooth; (iv.2) generating a first conical surface around said insertion axis (Z) from an end curve bordering the marginal surface generated in the sub-step (iv.1), this first conical surface extending parallel to said marginal zone and having an inclination towards the insertion axis of an angle corresponding to the volumetric reduction orientation angle of said marginal zone; (iv.3) generating a second conical surface around said insertion axis from an end curve bordering the first conical surface generated in the sub-step (iv.2), this second conical surface extending parallel to said middle zone and having an inclination towards the insertion axis of an angle corresponding to the orientation angle of volumetric reduction of said middle zone; (iv.4) calculating a second offset data for each point of the marginal and middle zones on the isolated three-dimensional representation of the at least one tooth, this second offset data corresponding to a displacement of this point towards or away from the insertion axis to displace this point on one of the first or second conical surfaces; and defining a primary reduction surface by moving each point from the marginal and middle zones towards the insertion axis according to: the second offset data of this point if it corresponds to a displacement towards the insertion axis and if it is larger than the first offset data of this point, and the first offset data of this point otherwise; (iv.5) generating an occlusal surface from an end curve bordering the primary reduction surface generated in the sub-step (iv.4) by a displacement of each point on the occlusal face on the isolated three-dimensional representation of the at least one tooth along the insertion axis according to the first offset data; and (iv.6) smoothing and/or regularising a total surface consisting of the assembly of the marginal, primary reduction and occlusal surfaces, this total surface having a plane tangent to the total surface at an intersection with the insertion axis perpendicular to the insertion axis.

8. The method according to claim 1, wherein: said second computer file consists of a file of modifiable STL format; and the step (v) comprises a validation and/or a modification of each of the geometric parameters relating to said three-dimensional representation of the volumetric reduction of said at least one tooth in a set of admissible values previously defined by at least one of said technical parameters determined in the step (iii).

9. The design method according to claim 1, wherein: said information of said third computer file comprises instructions for machining a material; and the step (viii) comprises a sub-step of machining said material on the basis of said machining instructions.

10. The design method according to claim 1, further comprising the step of: (vii′) generating a fourth computer file on the basis of said second validated and/or modified computer file, said fourth computer file comprising machining instructions for said at least one tooth corresponding to said three-dimensional representation of said volumetric reduction of said at least one tooth.

11. The design method according to claim 1, further comprising the following steps: (vii″) generating a fifth computer file on the basis of said second validated and/or modified computer file, said fifth computer file comprising information relating to the three-dimensional representation of the intrados of said prosthetic element obtained in the step (vi), this information comprising instructions for machining a rigid raw material corresponding to said three-dimensional representation of the intrados of said prosthetic element; and (viii″) machining a block of said rigid raw material on the basis of the machining instructions of said fifth computer file, so as to produce a control key of a machining of said at least one tooth corresponding to a machining according to said three-dimensional representation of the volumetric reduction of said at least one tooth.

12. The design method according to claim 11, further comprising the step of cutting the control key into slices parallel to a plane.

13. The design method according to claim 7, further comprising the following steps: (iv′) generating a sixth computer file on the basis of said first computer file and said dental protocol validated and/or modified in the step (iii.3), the sixth computer file comprising three collections of instructions for machining a rigid raw material, each of these collections comprising machining instructions for creating a cavity in the rigid raw material corresponding to the isolated three-dimensional representation, a first of the collections of instructions further comprising machining instructions for creating an access window at least partially conical around the cavity following the first and second conical surfaces, a second of the collections of instructions further comprising machining instructions for creating two windows of upper access to the cavity bordering mesial and distal faces of the cavity which correspond to the mesial and distal faces of said at least one tooth on the isolated three-dimensional representation, and a third of the collections of instructions further comprising instructions for machining a portion of the rigid raw material surrounding a middle zone of the cavity corresponding to the middle zone of said at least one tooth on the isolated three-dimensional representation, to create two sloping edges according to the orientation angle of volumetric reduction of the middle zone; and (viii′) machining a first, a second and a third block of said rigid raw material respectively on the basis of the first, second and third collections of machining instructions of said sixth computer file to produce three guides for machining the at least one tooth according to said three-dimensional representation of the volumetric reduction of the at least one tooth.

14. The design method according to claim 13, further comprising the step of interlocking at least one safety abutment and a rail for positioning a dental drill on the guides.

15. A set of apparatus for designing a prosthetic element by carrying out the design method according to claim 1, the set of apparatus comprising: at least one imaging apparatus for providing the first computer file of the step (i) of the design method; a computer system comprising: an interface for receiving: at least one technical parameter determined in the step (iii) of the design method, and validations and/or modifications of the second computer file of the step (v) of the design method; and to visualise and/or communicate data on: the intra-oral three-dimensional representation and the radiographic image of the first computer file provided in the step (i); the three-dimensional representation of the extrados of said prosthetic element obtained in the step (ii); the three-dimensional representation of the volumetric reduction of the at least one tooth of the second computer file generated in the step (iv); the three-dimensional representation of the volumetric reduction of the at least one tooth of the second computer file validated and/or modified in the step (v); and the three-dimensional representation of the intrados of said prosthetic element obtained in the step (vi); and a logic unit for at least partially implementing the steps (ii), (iv), (vi) and (vii) of the design method; and a production machine for reading the information from the third computer file generated in the step (vii), and for implementing the step (viii) of the design method.

16. A non-transitory computer-readable medium having logic stored thereon that in response to execution by a computer, causes the computer to perform actions comprising the steps of: executing a first set of instructions that implement step (iv) of the design method according to claim 1; and executing a second set of instructions that implement step (vii) of the design method according to claim 1.

17. The non-transitory computer-readable medium according to claim 16, wherein the steps further include generating a fourth computer file on the basis of said second validated and/or modified computer file, said fourth computer file comprising machining instructions for said at least one tooth corresponding to said three-dimensional representation of said volumetric reduction of said at least one tooth.

18. A computer-readable medium on which is recorded at least one of the sets of instructions according to claim 16.

19. A computer-readable medium on which is recorded: a third computer file generated by the design method according to claim 1.

20. A prosthetic element produced by the design method according to claim 1.

21. A control key produced by the design method according to claim 11.

22. Machining guides produced by the design method according to claim 13.

Description

DESCRIPTION OF FIGURES

[0194] Other characteristics and advantages of the present invention will appear when reading the following detailed description, for the understanding of which reference is made to the annexed figures among which:

[0195] the FIG. 1 shows a schematic view of a flow chart of a method for designing a prosthetic element according to a preferred embodiment of the invention;

[0196] the FIG. 2 shows a schematic view of an implementation of a dental restoration method comprising a method for designing a prosthetic element according to a preferred embodiment of the invention;

[0197] the FIG. 3 shows a simplified perspective view of a dental office equipped with an operator assistance system in a dental restoration described in the summary;

[0198] the FIG. 4 shows a three-dimensional view of elements of a robot and a spatial guidance system of the robot described in the summary;

[0199] the FIG. 5 shows a three-dimensional view of a control key according to the invention;

[0200] the FIG. 6 shows a three-dimensional view of a use of the control key illustrated in FIG. 5;

[0201] the FIGS. 7 to 9 show a top view of the guides according to the invention;

[0202] the FIG. 10 shows a three-dimensional view of a use of a guide according to the invention;

[0203] the FIG. 11 shows a schematic view of an implementation of the steps (iv.1) to (iv.6) of a method for designing a prosthetic element according to a preferred embodiment of the invention;

[0204] the FIG. 12 shows a particular application of the steps (iv.1) to (iv.6) of a design method according to a preferred embodiment of the invention.

[0205] The drawings of the figures are not to scale. Generally, similar features are denoted by similar references in the figures. In the context of this document, the identical or similar elements may have the same references. Furthermore, the presence of reference numbers or letters in the drawings cannot be considered as limiting, even where such these numbers or letters are indicated in the claims.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS OF THE INVENTION

[0206] The present invention is described with particular achievements and references to figures but the invention is not limited by them. The drawings or figures described are only schematic and are not limiting.

[0207] FIGS. 1 and 2 illustrate at least partially an implementation of a method of dental restoration of a tooth 91 of a dentition 92 of a patient P comprising a method for designing a prosthetic element 1 according to a preferred embodiment of the invention. Reference is hereafter made to the notations (i), (ii), (iii), . . . of the different steps of the design method introduced in the summary of the invention and in the claims.

[0208] It is assumed that the patient P is to undergo a dental restoration comprising milling of the tooth 91 and the placing of a prosthetic element consisting of a crown 1 on the milled tooth 91. The design method according to the invention is applied to the crown 1 to be designed. This method allows, according to a preferred embodiment, to be completed in such a way that the tooth 91 of the patient P can be restored easily and quickly.

[0209] To this end, the method proposes to the patient P to go to a three-dimensional imaging centre 81 and undergo an intra-oral scan of his dentition 92 by means of an intra-oral scanner 2, in order to carry out the step (i), i.e., to provide a first computer file 11 comprising an intra-oral three-dimensional representation of the dentition 92 comprising the tooth 91 to be restored by means of the crown 1. The three-dimensional imaging centre 81 is preferably one of: a dental office, a medical centre, or a local imaging centre. Advantageously, such a scan takes less than five minutes to complete; after this time, the patient P is released. It is preferably supplemented by a two-dimensional panoramic radiographic image of the mouth and/or the dentition 92 of the patient P, which is either attached to the first computer file 11, or provided simultaneously with the first computer file 11 in another first computer file 11′.

[0210] The panoramic radiographic image is preferably captured by means of an X-ray machine. It provides more information on the structure of the dentition 92 of the patient P, the associated nerves, the soft and hard tissues associated, comprising a comparison of the intra-oral three-dimensional representation with the radiographic image.

[0211] The first computer file 11 is then sent, via a computer-readable medium and/or via a shared data cloud, to a data centre 82 comprising a computer system 3 allowing the steps (ii) to (vii), and (vii′) of the design method to be carried out according to the preferred embodiment of the invention, in the order illustrated in FIG. 1, and as detailed in the summary of the invention. A dental technician and/or a specialised CAD designer processes the first computer file 11 to determine a representation of the crown 1, which comprises three-dimensional representations 1A and 1B of its extrados and intrados respectively, obtained from the steps (ii) and (vi) respectively. This representation is comprised in one or more computer files in STL format of CAD type designed at least partially by means of a first computer program according to the present invention. A second and a third computer program according to a preferred embodiment of the invention allows dental and prosthetic protocols to be used to generate a third 13 and a fourth 14 computer files of the CAM type which comprise instructions for machining respectively a ceramic material to form the crown 1, and the tooth 91 to fit the intrados 1B of the crown 1 during the placement.

[0212] The third computer file 13 is then sent, via a computer-readable medium and/or via a shared data cloud, to a laboratory 83 comprising a machining machine 4 allowing an implementation of the step (viii) of the design method according to the preferred embodiment of the invention. In particular, the machining machine 4 reads the third computer file 13 and executes the machining instructions so as to machine the ceramic material to form the crown 1, the extrados and the intrados of the crown 1 consisting of surfaces of a shape corresponding to the three-dimensional representations 1A and 1B. The fourth computer file 14 is sent via a computer-readable medium and/or a shared data cloud to a dental office 84 of a dentist and/or surgeon practitioner D equipped with an assistance system 5 as described in the summary. It has to be noted that a practitioner D with such a machining machine 4 in the dental office 84 can receive the third computer file 13 and produce the crown 1 he needs himself. In particular, the locations 81, 83 and 84 are likely to coincide.

[0213] The practitioner D, having the fourth computer file 14 at his disposal, then carries out the dental restoration operation by milling the tooth 91 and attaching the crown 1 to the milled tooth. This operation is well known, but it can be significantly improved within the scope of the invention because the tooth 91 is milled with the help of the assistance system 5 described in the summary and in such a way as to fit into the already designed crown 1, and not the other way round. Thus, the operation lasts less than thirty minutes and the patient P regains a smile when leaving the dental office.

[0214] The procedure leading to the dental restoration is now described in FIG. 3, which shows a simplified view of an operating room of the dental office 84 equipped with an assistance system 5 as described in the summary. The elements of the dental office 84 shown in FIG. 2 are all illustrated in FIG. 3. The room comprises standard technical tools of the practitioner D such as a seat 84A to accommodate the patient P, a station 84B comprising a water supply and a tower carrying a lamp 84C placed high up, and a mobile arm extending around the seat 84A, to which a pallet 84D of standard instruments of the practitioner D is mechanically coupled. The assistance system 5 comprises a robot 6 which is mobile around the seat 84A, in a zone 80R. It is equipped with wheels to ensure its mobility. It is also equipped with a robotic articulated arm 61 which is mobile and attached to a machining tool consisting of a dental drill 62 placed at one end of the robotic arm 61. The assistance system 5 also comprises a spatial guidance system for the robot 6 comprising a detector 73, preferably attached to a lamp support 84C, overhanging the seat 84A. As shown in FIG. 4, the detector 73 is configured to determine: [0215] a first distance separating one of its points of at least one of the first target symbols 74 from a first spatial reference frame 71 attached to the robotic arm 61; [0216] a second distance separating the one of its points from at least one of the second target symbols 77 of a second spatial reference frame 72 which is attached to a point in an operating zone of the dentition 92.

[0217] To allow the detector 73 to determine these first and second distances with depth, in any direction in space, two cameras 73A and 73B spaced on the detector 73 are provided. The second spatial reference frame 72 comprises a dental part 75 which is adapted to fit into a portion of the dentition 92 comprised within the operating zone, which portion does not comprise the tooth 91, and a protruding element 76 comprising the second target symbols 77. The dental part 75 and the protruding element are provided with a female-male attachment system 78 which allows a male end of the protruding element 76 to be clipped into a female end of the dental part 75, so that the protruding element 76 can be advantageously reused from one dental operation to the next, while discarding the dental part 75 after use. Preferably, the dental part is made of a solid and inexpensive material from the first computer file 11 to make a partial dental impression that fits perfectly into the portion of the dentition 92. The dental part 75 is, for example, designed by an additive manufacturing process. It is necessary to design the protruding element as extending outside the operating zone to facilitate the visibility of the second target symbols 77 by the detector 73 while ensuring that the second spatial reference frame 72 reports the movements of the patient P relative to a fixed room reference frame and the robotic arm 61. Finally, the spatial guidance system comprises a computer logic unit 52 comprising a processor arranged within a robot housing 6, so as to limit the space requirement of the assistance system 5. The computer logic unit 52 is configured to: [0218] reading the fourth computer file 14, [0219] receiving data on the first and second distances from the detector 73, and [0220] determining information for comparing the data with the machining instructions of the fourth computer file 14, [0221] controlling and/or stopping the robot 6 and/or the dental drill 62 according to the comparison information.

[0222] The assistance system 5 also comprises a communication tool 51 digitally connected to the computer unit 52 and comprising a screen to communicate the comparison information to the practitioner D. Thus, and as detailed in the summary of the invention, the practitioner D can be guided in his milling by the assistance system 5 in such a way as to guarantee a high degree of reliability and speed of the operation, as well as a high degree of milling precision, and in particular, obtaining a surface of the milled tooth 91 corresponding exactly to the intrados of the crown 1 to be placed. Optionally, the robot 6 comprises another mobile mechanical arm comprising another detector 73′ of a structure and for a use similar to the detector 73′. Optionally, the robot 6 comprises another tool 51′ of a structure and a use similar to the communication tool 51. In particular, it is digitally connected to the computer unit 52 to communicate and/or receive comparison information to the practitioner D. It preferably consists of one of a laptop computer, or an interactive tablet, for the practitioner D. During the dental surgery operation, the practitioner D acting as an assisted operator is essentially located in a zone 80D, surrounded laterally by the zone 80R.

[0223] The procedure leading to the dental restoration described in FIGS. 3 and 4 is advantageously (semi-)automated with the aid of the assistance system 5 as described in the summary. However, this assistance system 5 is likely to be expensive and complex to implement. The invention therefore proposes inexpensive and very advantageous alternatives for control key and guides for machining the at least one tooth 91. This control key 100 and these guides 110, 120 and 130 are introduced precisely in the summary of the invention and illustrated in FIGS. 5 to 10. The control key 100 is formed from a block of rigid raw material which is machined by means of the embodiments of the invention, so that the three-dimensional representation of the intrados 13 of the prosthetic element 1 is formed from a lower face of the block. Preferably, three-dimensional representations of the adjacent teeth 91A and 91B are also machined in a similar manner. The control key 100 therefore acts as a mould that can be placed on the dentition 92 of the patient when the at least one tooth 91 has been prepared by a practitioner. The control key 100 thus allows the practitioner to detect any cutting errors in the at least one tooth 91. To facilitate this, the control key 100 is cut into slices 101 parallel to a plane (vertical in the case illustrated, but which can just as easily be horizontal). In this way, the practitioner can move certain slices 101 so that he can observe the evolution of its cutting and its good correspondence with the intrados 1B of the prosthetic element 1. This is shown in particular in FIG. 6. The guides 110, 120 and 130 are for their part directly associated with the practice of machining the at least one tooth 91 with regard to the method comprising the steps (iv.1) to (iv.6) as explained in the summary of the invention. They are shown from above (downstream of the insertion axis when arranged on the at least one tooth 91) in FIGS. 7 to 9 and are obtained by applying the first, second and third collections of machining instructions to the first, second and third blocks of a transparent rigid raw material respectively, as explained in the summary of the invention. Each comprises a cavity 91′ in this raw material corresponding to the isolated three-dimensional representation of the at least one tooth 91 which is obtained by the step (iii.1). Windows 111, 121 and 132 are provided in the guides 110, 120 and 130 respectively to access this cavity 91′ according to the directions and angles of attack for the dental cutting adapted to best reproduce certain sub-steps or results resulting from sub-steps of the step (iv). The guide 130 is machined so that two sloping edges 131 are created giving a roof shape to this portion of the block of raw material, the slopes being determined according to an orientation angle of volumetric reduction of the middle zone of the at least one tooth 91 comprised in the dental protocol according to the step (iii). The placement of such a guide 110 during the dental preparation is shown in FIG. 10. These guides 110, 120, 130 guide the machining of the at least one tooth 91 to reproduce in particular the primary surface according to the sub-step (iv.4). Other such guides can be derived from the sub-steps of the step (iv) without departing from the scope of the invention.

[0224] The decomposition of the step (iv) into the sub-steps (iv.1) to (iv.6) is commented in the summary of the invention and illustrated in FIG. 11 with respect to a crown, this choice being not limitative as these sub-steps apply effectively to the case of other prosthetic elements 1, since they influence a choice of insertion axis Z by the dental protocol according to the step (iii.1) to (iii.3). Thus, this figure can be used to illustrate these sub-steps according to the following references. The elliptical fillets 201 are generated in the sub-step (iv.1) at the marginal zone of the at least one tooth 91, the first conical surface 202 (this one being approximately cylindrical) is generated in the step (iv.2) around the marginal zone of the at least one tooth 91, the second conical surface 203 is generated in the step (iv.3) around the middle zone of the at least one tooth 91, the step (iv) allows to compare the conical surfaces 202 and 203 with an offset surface that would be obtained by moving each point of the marginal and middle zones towards the insertion axis Z according to the first offset data from the dental protocol. This is because it is possible for particular teeth that points on the conical surfaces 202 and 203 are outside the (three-dimensional representation of the) at least one tooth 91, so that it would no longer make sense to define a volumetric reduction of the at least one tooth 91 on this basis. This is illustrated in FIG. 12 in particular. It is therefore necessary to project these points into the (three-dimensional representation of the) at least one tooth 91. This projection must be made taking into account that it must “enter far enough” into the (three-dimensional representation of the) at least one tooth 91 to ensure sufficient space for the prosthetic element 1, as this has a certain thickness. It is the great interest of first offset data that comes from the dental protocol and encode sort of a preference this minimum thickness that is necessary to remove on each face of the at least one tooth 91 in order to be able to place the prosthetic element 1 taking into account the tolerances associated with it. Thus the step (iv.4) proposes this advantageous and judicious correction of the conical surfaces 202 and 203 to allow a suitable primary reduction surface to be defined for carrying out the volumetric reduction of the at least one tooth 91. Next, a reduced occlusal surface 204 is generated in the step (iv.5) and finally a final total surface 205 is generated in the step (iv.6), which consists of the assembly of the fillets 201, the smoothed and regularised primary reduction and occlusal surfaces 204.

[0225] In summary, the invention concerns, a method for designing a prosthetic element 1 that can be executed prior to a cutting of a tooth 91 of a patient for the placement of the prosthetic element 1.

[0226] The present invention has been described in relation to specific embodiments, which are purely illustrative and should not be considered as limiting. In a general manner, it will be obvious to a person skilled in the art that the present invention is not limited to the examples illustrated and/or described above. The invention comprises each of the new features as well as all their combinations.