METHOD FOR DEFINING DIFFERENT LAYER ELEMENTS OF AN ARTIFICIAL DENTAL ELEMENT

Description

[0001] The invention relates to a method for defining different layer elements of an artificial tooth element.

[0002] When manufacturing artificial teeth, a key goal is to ensure that the artificial tooth resembles the patient's natural teeth as closely as possible. In natural teeth, the dentin is surrounded by enamel in the visible area. It is particularly difficult to replicate the appearance of old teeth, as these often exhibit additional effects.

[0003] For the production of dental elements, which can be a complete artificial tooth, a crown, or the like, it is known to manufacture the dental element from at least two different materials and to replicate the boundary between dentin and enamel. For this purpose, it is known from DE 10 2010 002 484 A1 to determine the boundary between dentin and enamel on the patient's natural tooth using an X-ray procedure and then to produce a dental element in which an inner material simulating the dentin has the same geometric shape as the patient's natural dentin and, in particular, to form the layer thickness of the material replacing the enamel according to the thickness of the natural enamel.Since the materials replacing the enamel and dentin in the artificial tooth element do not have the same optical properties as natural materials, artificial tooth elements produced in this way continue to differ in appearance from the patient's other teeth. Further prior art is provided by US 2018 / 116772, US 2010 / 105011, EP 1 252 867, and EP 2 363 094.

[0004] The object of the invention is to provide a method for defining different layer elements of an artificial tooth element in order to create an artificial tooth element whose optical properties correspond to or are as close as possible to the optical properties of the patient's natural tooth.

[0005] The object is achieved according to the invention by a method according to claim 1.

[0006] According to the method according to the invention, an interface is first defined between an inner core element and at least one outer layer element that at least partially surrounds the inner core element. Compared to the natural tooth, the inner core element corresponds to the area in which the tooth has dentin. Compared to the natural tooth, the outer layer element corresponds, in particular, to the area that has enamel.

[0007] The definition of the interface can be done in such a way that a representation of the actual interface between enamel and dentin of the natural tooth to be reproduced is obtained.

[0008] Preferably, at least one interface is defined inside an artificial tooth element, although this does not necessarily have to correspond to the natural interface. The at least one interface represents an interface between at least two different materials from which the artificial tooth element is made. This interface does not correspond, or at least not completely, to the interface between dentine and enamel of the patient's natural tooth, or is not defined taking the actual interface into account. By defining at least one different interface, i.e. one that differs at least partially from the natural interface, the optical properties of the materials used are utilized in such a way that the optical appearance of an artificial tooth element produced in this way comes as close as possible to the optical appearance of the natural tooth and preferably essentially corresponds to it.

[0009] First, according to the invention, the three-dimensional outer contour of the tooth element is determined. The outer contour of the artificial tooth element corresponds to the outer contour of the natural tooth to be replaced. This can be done, for example, by selecting a suitable outer contour from a tooth library, which is adapted to the individual anatomy in order to meet the functional and aesthetic requirements of the restoration to be produced. As an alternative to selecting the shape from a tooth library, for example, in the case of a single crown, the tooth contour of the opposing tooth can also be mirrored. In a step preceding the method according to the invention, a three-dimensional outer contour of a tooth element can be determined and, in particular, recorded. It is also possible to open a data set containing the three-dimensional outer contour of the tooth element.

[0010] Furthermore, in preparation for the method according to the invention, a three-dimensional outer contour of the tooth element can be aligned to a coordinate system. The coordinate system is preferably related to anatomically defined directional designations, so that the coordinate system includes, in particular, the mesial, distal, apical, and incisal / occlusal directions. Aligning a tooth element to a coordinate system has the advantage that, starting from the three-dimensional outer contour of the tooth element, it is easily possible to define at least one interface located inside the tooth element.

[0011] A first boundary curve is defined on the tooth surface. A first boundary curve can be defined based on the tooth equator. The tooth equator is the largest circumference of a tooth in the region of the tooth crown. Likewise, the first boundary curve can also be based on a preparation margin as a curve, whereby the preparation margin represents the boundary between the artificially processed tooth element and the unprocessed tooth surface. It is also possible to define the first boundary curve at least partially manually. Manual adjustment of a curve that is defined, for example, based on the tooth equator and / or the preparation margin, in particular automatically, is also possible. It is preferred that the first boundary curve is defined between the tooth equator and the preparation margin. In this case, it is possible, for example, to define the first boundary curve at a fixed distance from the tooth equator and / or the preparation margin.In particular, the first limit curve can have the same distance to the tooth equator and to the preparation border, ie be provided exactly between the tooth equator and the preparation border.

[0012] Based on the first boundary curve, an incisal or occlusal tooth surface is determined. According to the invention, this tooth surface is shifted inward. The shift occurs in the direction of the surface normal, with the shift occurring in particular by varying amounts. Thus, there are areas of the tooth surface that are shifted inward to a greater or lesser extent. These different amounts of shift are based on variable design parameters. By shifting the tooth surface in this way, the at least one boundary surface is created.

[0013] The design parameters can vary, especially depending on the patient's teeth. Different design parameters may also be necessary, for example, if the restoration is being made on differently colored tooth stumps or if the restorations have different thicknesses, as the optical appearance of the tooth stumps influences the appearance of the artificial tooth element due to the translucency of the materials used for the artificial tooth element. The design parameters also depend, in particular, on the material used. For example, a minimum wall thickness of a material may be specified. This is particularly the case for the inner, particularly dentin-colored material, which essentially determines stability. Furthermore, the optical properties of polymer-based material differ from those of purely ceramic materials.

[0014] In a preferred development of the method, the variable design parameters describe a maximum first displacement of the tooth surface and / or a first length for defining a transition surface.

[0015] Preferably, the first displacement is selected such that, for anterior and posterior teeth, no displacement occurs immediately at the first boundary curve. For posterior teeth, no displacement occurs at the central fissure. The amount of the first displacement then increases, preferably continuously, in the direction of the surface normal incisally or occlusally, starting from the first boundary curve, until the amount of the displacement reaches the maximum first displacement.

[0016] The transition surface can be defined, for example, by specifying the design parameter of the first length. Thus, the first length preferably defines a transition region starting from the first limit curve. This is defined from zero to the full first displacement. A transition region is provided to realize a particularly smooth transition starting from the first limit curve to the full first displacement. By defining such a transition surface, it is possible to recreate the natural appearance of a tooth, in which the enamel becomes progressively thinner in the apical direction.

[0017] A transition surface can also be defined by projecting the first boundary curve incisally or occlusally by the first length, whereby this projection defines a second boundary curve. The transition surface is then defined between the first and second boundary curves.

[0018] It is therefore particularly preferred that the definition of the at least one interface inside the artificial tooth comprises at least the following steps: Definition of a first boundary curve on the tooth surface, determination of a tooth surface located incisally / occlusally with respect to the first boundary curve and displacement of this tooth surface inwards in the direction of the surface normal by different amounts to generate the at least one boundary surface, in particular the first boundary surface.

[0019] Preferably, the variable design parameters describe a maximum first displacement of the tooth surface and a first length for defining a transition surface, wherein in the case of anterior and posterior teeth directly at the first boundary curve and in the case of posterior teeth additionally at the central fissure, no displacement occurs upon a first displacement and wherein the amount of the first displacement in the direction of the surface normal incisally / occlusally increases continuously starting from the first boundary curve until the maximum first displacement is reached, wherein the first length is defined as a design parameter.

[0020] Furthermore, the first boundary curve can be projected incisally / occlusally by the first length to define a second boundary curve, wherein the transition surface between the first and the second boundary curve is defined.

[0021] After defining an interface between the inner core element and at least one outer layer element at least partially surrounding the inner core element, at least one additional layer element is selected according to the invention. According to the invention, an additional layer element is selected from a provided selection list containing a plurality of additional layer elements. In particular, this can be a selection list or selection box displayed on a screen, so that a dentist or dental technician can easily select one or more additional layer elements contained in the selection list, for example by simply clicking or marking them. The dentist or dental technician therefore does not have to model the corresponding additional layer elements or the like, but merely has to select them.The at least one selected additional layer element is then automatically arranged in a spatially defined relationship to the core element and / or the outer layer element according to the method according to the invention. If necessary, the automatic arrangement can be displayed directly on a screen, so that the dentist or dental technician already has an initial impression of whether the selection of one or more additional layer elements will bring the visual appearance of the artificial tooth element to be inserted close to the natural tooth.

[0022] The automatic arrangement of the at least one selected additional layer element occurs in a spatially defined relationship to the core element and / or the outer layer element. Preferably, the automatic arrangement is based on anatomical features and / or auxiliary lines or auxiliary points. The auxiliary lines and / or auxiliary points are preferably created or defined on the surfaces based on anatomical features. In particular, the anatomical features and definitions of the auxiliary lines and / or auxiliary points are different for each layer element. This preferably occurs as described below with respect to the respective layer elements.

[0023] The selection list may include in particular: accentuation of mamelons and / or chromatic neck and / or translucency effect and / or halo effect and / or horizontal band and / or surface effect.

[0024] The additional layer elements "translucency effect" and "halo effect" are, in particular, subgroups of an additional layer element "incisal / occlusal optical effect".

[0025] To further improve the visual appearance of the artificial tooth element, it is preferably possible to select a material and / or color for at least individual additional layer elements. An additional layer element can also be made of different materials, have different colors, or have a color gradient. If an additional layer element is provided in the artificial tooth element not just once but multiple times, it is preferably possible to select different materials, colors, and the like for it, so that a corresponding material and / or color selection can be made separately for each additional layer element.

[0026] When selecting the additional layer element "accentuation of mamelons," it is preferred that it be arranged on the core element in the region of the mamelon. The at least one mamelon is preferably defined by the interface. It is possible to form several additional layer elements such that different additional layer elements "accentuation of mamelons" are arranged on different mamelons. It is particularly preferred that the additional layer element "accentuation of mamelons" is arranged at least partially within the outer layer element. In particular, to form the additional layer element "accentuation of mamelons," the interface is shifted on at least one mamelon. The interface is shifted in particular in the incisal direction.

[0027] It is preferred that the additional layer element "accentuation of mamelons" be arranged on the mamelon defined by the interface. In particular, the additional layer element "accentuation of mamelons" is placed on the mamelon similar to a cap or hat.

[0028] In a preferred development of the method according to the invention, control points of at least one mamelon are defined. The control points are preferably high points. A high point defines the tip or the upper region of the mamelon. Control points, which are in particular high points, are preferably shifted incisally. Low points, i.e. the deepest points between adjacent mamelons, are preferably not shifted. A polygon that defines the outer contour of the mamelons thus has maxima that correspond to the high points of the mamelons and minima that correspond to the low points in the valleys between the mamelons. In a preferred embodiment, the maxima of the polygon are thus shifted incisally, whereby the minima are not shifted.

[0029] It is particularly preferred that the additional layer element "accentuating mamelons" be formed in the area between the interfaces before and after the interfaces are shifted. The shift is preferably in the range of 0 to 1 mm and in particular in the range of 0 to 0.7 mm.

[0030] To define such a polygon, a third or additional boundary curve can first be defined or created. This is done by projecting the first or second boundary curve by a second length, whereby the provision of a second boundary curve is optional. In particular, the third or additional boundary curve is created by incisal or occlusal projection of the first boundary curve or by apical projection of the second boundary curve. Alternatively, the third boundary curve can be created independently of the first or second boundary curve, manually or based on other features of the tooth element, for example, the equator or the preparation margin.

[0031] Furthermore, an incisal or occlusal first surface contour is preferably determined. The first surface contour is defined by the highest curve on the first interface created by the first maximum displacement. The highest curve can be determined automatically and, if necessary, manually corrected. Node points are created or defined on the first surface contour. The node points are then at least partially shifted in the apical or incisal / occlusal direction. The at least partially shifted node points are connected to one another with a second surface contour. The second surface contour created in this way defines the maximum second displacement of the tooth surface (or the first interface) in the area of ​​the incisal or occlusal surface contour. Preferably, two different mamelon curves are created, which generate the second displacement according to the method steps described below.Two different mamelon curves create two different geometries. Subtracting the smaller geometry from the larger one creates spaces in which the additional layer elements "Accentuate Mamelons" are placed.

[0032] In this preferred embodiment of the method according to the invention, the amount of the second displacement decreases continuously in the apical direction in the direction of the surface normal for anterior and posterior teeth by a third length until the third limit curve or a length defined as the maximum for this purpose is reached. For posterior teeth, the amount of the second displacement also decreases continuously in the direction of the central fissure until the central fissure is reached. Preferably, the amount of the second displacement is "0" immediately at the third limit curve or immediately at the central fissure. The central fissure can also be defined manually, and / or a manual correction of an automatically defined or predefined central fissure can be performed.

[0033] Preferably, the maximum first displacement of the tooth surface is in the range of 0 mm to 4 mm.

[0034] Furthermore, it is preferred that the first length required to create the transition surface has an extension of 0.1 mm to 10 mm.

[0035] In a preferred embodiment of the invention, a boundary, i.e. the beginning and the end of the automatically determined highest curve on the first and / or second incisal surface contour, is defined by an angle for anterior teeth. The angle is an angle between the tangents on the incisal surface contour and the tooth axis, wherein the angle is 0° to 90°, preferably 10° to 70° and particularly preferably 40° to 50°. The tooth axis is defined for teeth as the connecting line between the root tip in single-rooted teeth and the center of the incisal edge or chewing surface, and in multi-rooted teeth between the root bifurcation and the center of the chewing surface. In particular, it is also possible to manually define or adapt the boundaries, i.e. the beginning and the end, as well as if necessary the course of the incisal surface contour.

[0036] Preferably, the position of the node points on the incisal surface contour of anterior teeth is specified or defined relative to the total length of the incisal surface contour. It is preferred that at least five points be defined on the incisal surface contour. It is preferred to define a larger number of points, in particular more than 10 and particularly preferably more than 20 points.

[0037] For posterior teeth, it is preferred that the position of the node points on the incisal / occlusal surface contour per cusp be specified relative to the lengths of the cusp degrees. In particular, the length of the cusp degrees between the mesial cusp beginning and the cusp tip, or between the cusp tip and the distal cusp end, is used. It is preferred, in turn, that at least five points be defined per cusp along the total length of the occlusal surface contour. A higher number of points, at least 10, and in particular at least 20, is preferred.

[0038] The displacement of the node points on the incisal / occlusal surface contour in the apical direction is preferably in the range of -4.0 mm to +4.0 mm.

[0039] In addition to or instead of providing one or more additional layer elements for "accentuating mamelons," the additional layer element "chromatic neck" can be selected. To match the visual appearance of the artificial tooth element to the natural tooth, it is often appropriate and necessary to adjust, especially intensify, the tooth color in the neck area. Particularly preferred is the use of material with a shade that is more intense than the shade of the dentin. In particular, this involves a yellowish and / or brownish hue of the tooth.

[0040] When the additional layer element "chromatic tooth neck" is selected, this material is at least partially colored in an area of ​​the outer layer element located apical to a boundary curve.

[0041] To form the additional layer element "chromatic tooth neck," the material of the outer layer element can be colored. Additionally or alternatively, an additional element made of a different material can be provided to form the additional layer element "chromatic tooth neck." This is then preferably arranged within the outer layer element. If necessary, no outer layer element is provided in the area where the additional layer element "chromatic tooth neck" is arranged, since the outer layer element may not extend into the lower region of the tooth neck. In this respect, the additional layer element "chromatic tooth neck" can also be provided entirely or partially within the core element, with the core element possibly forming the outer layer of the artificial tooth element in the region of the tooth neck.

[0042] Preferably, the additional "chromatic tooth neck" layer element is delimited by the outer contour of the outer layer element. To improve the visual appearance, it is also possible for the additional "chromatic tooth neck" layer element to be partially arranged beneath the outer layer element, particularly if the outer layer element extends completely to the underside of the tooth, thus covering at least part of the tooth neck with the outer layer element.

[0043] Furthermore, it is possible, particularly to create a continuous color transition, to change the layer thickness of the additional layer element "chromatic neck of the tooth" so that it decreases particularly in the apical and / or incisal or occlusal direction.

[0044] In addition to or instead of the additional layer elements "accentuation of mamelons" and / or "chromatic neck of tooth" described above, it is preferable to provide an additional layer element "incisal / occlusal optical effect." The additional layer element "incisal / occlusal optical effect" is, in particular, the additional layer element "translucency effect" or "halo effect."

[0045] A translucency effect or transparency effect often occurs in the incisal region of a crown or tooth. The additional layer element "translucency effect" is preferably arranged in an incisal edge region of the artificial tooth element within the outer layer element. It is preferred that the additional layer element "translucency effect" is delimited by the outer contour of the outer layer element, with the additional layer element "translucency effect" being arranged on the outer edge of the artificial tooth, so that the additional layer element "translucency effect" forms the outer contour of the tooth.

[0046] To define the additional layer element "translucency effect," control points are preferably arranged automatically on the surface of the outer layer element. These are then moved apically.

[0047] The additional layer element "Translucency Effect" is preferably arranged as described for the additional layer element "Accentuation Mamelons," based on the definition of the polygon. However, the outer contour is preferably reduced to a lesser extent.

[0048] Preferably, the displacement occurs along a normal to the surface of the outer layer element. It is particularly preferred that the displacement occurs by 0 to 1 mm, in particular 0 to 0.5 mm.

[0049] Furthermore, it is preferred that the additional layer element "translucency effect" be formed in the area between the surface of the outer layer element before and after displacement. It is particularly preferred that the outer contour of the additional layer element "translucency effect" be delimited by the original outer contour of the outer layer element.

[0050] Another optical effect is the halo effect. In this respect, the dentist or dental technician can select the additional "Halo Effect" layer element in addition to or instead of the additional layer elements described above. The halo effect is a slight, bright accentuation of the incisal edge of the artificial tooth element. This is usually less pronounced than the translucency. The arrangement, size, etc., of the additional "Halo Effect" layer element should preferably correspond to the additional "Translucency Effect" layer element. The additional "Halo Effect" layer element is preferably less pronounced than the additional "Translucency Effect" layer element.

[0051] Another additional or alternative additional layer element is the additional layer element “horizontal band”.

[0052] For the particularly automatic arrangement of the additional layer element "horizontal band," it is preferable that a horizontal line is first defined on the tooth element. Relative to the height of the tooth element, it is preferable to position the horizontal line approximately in the middle region of the tooth element. In particular, the horizontal line is defined relative to the center of the height of the tooth element ± 10%. Starting from the horizontal line, the horizontal band extends in both directions by a predetermined width. This is preferably in the range of 0.3 to 2 mm. In addition to this incisal / apical extension, the horizontal band preferably has a depth of 0.2 to 1.5 mm. It is further preferable that the horizontal band is arranged between the core element and the outer layer element and, in particular, protrudes into the core element and / or the outer layer element.

[0053] As with the other additional layer elements, a material, possibly several different materials, and a color scheme can be selected for the additional layer element "Horizontal Band", which can also be a color gradient or different colors.

[0054] Another additional layer element is the "surface effect" additional layer element. The "surface effect" additional layer element is arranged on the interface (i.e., the area between the core element and the outer layer element) in a frontal area. The frontal area is the visible area of ​​the tooth facing forward when the tooth element is inserted. The "surface effect" additional layer element is particularly relevant for incisors. To arrange the "surface effect" additional layer element, a virtual mesh, in particular, can be arranged on the interface. This mesh has crossing or intersection points. By selecting appropriate intersection points, the area in which the "surface effect" additional layer element is arranged can be defined. The "surface effect" additional layer element has a width of preferably 1 to 8 mm, a height of preferably 1 to 10 mm, and a depth of preferably 0.1 to 1 mm.Furthermore, the additional layer element "surface effect" extends into the core element and / or the outer layer element.

[0055] If necessary, the additional layer element "Accentuation Mamelons" can be covered with the additional layer element "Surface Effect" or with the additional layer element "Horizontal Band".

[0056] Particularly preferred for implementing the method according to the invention is the provision of a virtual mesh that is placed on the surface of the outer layer element. This allows control points, which are in particular intersection points of the mesh lines, to be automatically defined. These control points can then be used to define the position and extent of individual additional layer elements. This enables, in particular, a precise and automatic placement of the individual additional layer elements.

[0057] Preferably, the vertical and horizontal extent of the virtual mesh is defined by the maximum vertical and horizontal extent of the outer contour silhouette of the tooth element. Furthermore, it is preferred that the mesh comprises vertical and horizontal lines that preferably divide the tooth contour equidistantly. The outer contour silhouette is the projected contour of the tooth element in a front view.

[0058] All additional layer elements can be arranged individually or in combination with one another. In addition to the preferred selection of materials, colors, color gradients and the like, a dentist or dental technician can also define the position and characteristics, e.g. the dimensions of the individual additional layer elements. The system preferably automatically suggests a position and characteristics for the corresponding additional layer elements depending on the type and patient-specific size of the tooth element. Appropriate dimensions can, for example, be defined automatically using the defined size or the external dimensions of the additional tooth element. It is also possible for a system to automatically suggest shapes, materials, etc. This can be done, for example, by automatically comparing photographs or images with the natural tooth to be replaced.other, particularly adjacent, natural teeth of the patient.

[0059] The invention is explained in more detail below using preferred embodiments with reference to the accompanying drawings.

[0060] They show: Fig. 1 a schematic front view of an artificial tooth element of a front tooth, Fig. 2 a schematic side view of an artificial tooth element of a front tooth, Figs. 3 and 4 a schematic front view and side view of an artificial tooth element of a front tooth respectively Figures 1 and 2 , where additional surfaces and curves are shown, Figs. 5 and 6 a schematic front view and side view of an artificial tooth element of a front tooth corresponding Figures 1 and 2 , where additional surfaces and curves are shown, Fig. 7 an incisal view of the Fig. 5 illustrated tooth element, Figs. 8a to 8c alternative representations of the Fig. 5with different tangent angles, Fig. 9 a schematic representation of a first and a second surface contour, Fig. 10 a schematic front view of a tooth element of a front tooth corresponding Figures 1 and 2 , where additional surfaces and curves are shown, Fig. 11 a schematic side view along the section plane XI in Fig. 10 , Fig. 12 a schematic side view of an artificial tooth element of a posterior tooth, Fig. 13 a schematic view of incisal of the Fig. 12 shown artificial tooth element of a posterior tooth, Fig. 14 a schematic front view of a section of an artificial tooth element for determining the arrangement of the additional layer element "accentuation of mamelons", Fig. 15 a side view of the in Fig. 14illustrated artificial tooth element, Fig. 16 a front view and a side view of an artificial tooth element together with the additional layer element "accentuation mamelons", Fig. 17 a front view and a side view of an artificial tooth element showing the additional layer element "chromatic tooth neck", Fig. 18 a detailed view of an artificial tooth element to illustrate the additional layer element "chromatic tooth neck", Fig. 19 a front view and a side view of an artificial tooth element to illustrate the additional layer element "translucency effect", Fig. 20 a front view and a side view of an artificial tooth element to illustrate the additional layer element "horizontal band", Fig. 21 a front view and side views of an artificial tooth element to illustrate the additional layer element "surface effect", Fig.Fig. 22 shows a front view and a side view of an artificial tooth element with a virtual mesh, Fig. 23 shows a front view and a side view of an artificial tooth element with a virtual mesh in conjunction with the production of the additional layer element "translucency effect", and Fig. 24 shows a front view and a side view of an artificial tooth element with a virtual mesh in conjunction with the production of the additional layer element "surface effect".

[0061] To carry out the method according to the invention, it is first necessary to define an interface between an inner core element and an outer layer element that at least partially surrounds this core element. A possible method for defining this interface is described below using the Figures 1 to 13 explained in more detail.

[0062] In the Figures 1 and 2An artificial tooth element 10 of an anterior tooth is shown in front and side views. This is the three-dimensional outer contour of the tooth element, wherein preferably a corresponding data set has been opened which includes the data of the three-dimensional outer contour of the tooth element. After aligning the tooth element 10 to a coordinate system (not shown), a first boundary curve 12 is defined, wherein the first boundary curve 12 can be defined manually and / or based on a preparation margin or on the basis of a tooth equator. In the incisal direction, ie in Figures 1 and 2 above the first limit curve 12, a tooth surface 14 is defined by the first limit curve 12.

[0063] The tooth surface 14 is turned inwards in the direction of the surface normal to create a first boundary surface 16 ( Figures 3 and 4 ). A maximum displacement of 17 is shown as an example.

[0064] As in Figures 3 and 4 As shown, based on a preferred embodiment of the invention, a transition surface 18 extending in the incisal direction 19 can be defined starting from the first boundary curve 12. In the illustrated embodiment, the transition surface 18 is defined in such a way that a second boundary curve 20 is defined. The second boundary curve 20 can be created by projecting the first boundary curve 12 by a first length 22.

[0065] In the illustrated embodiment, a third limit curve 24 ( Figures 5 and 6 ). The third limit curve 24 can be created by projecting the first limit curve 12 by a second length 26.

[0066] The highest curve on the first boundary surface (16) created by the first maximum displacement is defined as the incisal / occlusal first surface contour 28. The first surface contour 28 has two boundaries 30, or in particular a beginning and an end. The boundaries 30 are defined by tangents 32. Fig. 5 the tangents 32 have an angle of approximately 45° to the tooth axis 34.

[0067] As in the Figures 8a to 8c As shown, the position of the limits 30 changes when the tangent angle changes.

[0068] In top view or incisal view ( Fig. 7 ) the course of the first surface contour 28 is shown.

[0069] On the surface contour, a number of nodes ( Fig. 9 ). These nodes are shown as an example in Fig. 9labeled node 1 to node 9 and listed in a table. As indicated by arrows, the nodes located on the first surface contour 28 are shifted in the apical direction. Connecting the shifted nodes results in the second surface contour 36.

[0070] From the above method steps, a three-dimensional boundary surface results in the illustrated embodiment, which is defined by the third boundary curve 24, parts of the first boundary surface 16 and the second surface contour 36 ( Figures 10 and 11). Within this three-dimensional area, i.e., in the space 38, a different material is provided in a preferred embodiment of the invention than in the volume of the artificial tooth element 10 surrounding this space. These two volumes are defined, in particular, by different materials, with the inner volume 38 simulating the dentin. The interface between the volume forming the dentin and the surrounding volume is not identical to the corresponding interface of the associated natural tooth.

[0071] In the Figures 12 and 13 The corresponding contours of a posterior tooth are shown, corresponding to the contours described for the protruding edge of an anterior tooth. In addition, the central fissure 40 ( Fig. 13). The line representing the central fissure 40 has two boundary points 42, which represent the cusp beginning and the cusp end, respectively. Furthermore, 36 cusp tips 44 are drawn on the second surface contour. A point 46 designates a cusp end and the cusp beginning of the next cusp.

[0072] In a three-dimensional interface defined according to the above method steps, the inner volume 38 forms the inner core element and the volume 50 surrounding the inner volume 38 forms the outer layer element.

[0073] To arrange the additional layer element "Accentuation Mamelons," high points 54 are defined on the silhouette curve 52, i.e., the boundary curve between the inner core element 38 and the outer layer element 50 in a preferred embodiment. The high points 54 are shifted incisally so that points 56 are defined. The position of the silhouette curve 52 is changed accordingly. Between the silhouette curve 52 and the boundary surface 58 defined by the points 56 after the incisal shift, gaps 60 are created. The additional layer elements "Accentuation Mamelons" are arranged in these gaps 60. These can be colored differently or made of different materials, as shown in particular in Fig. 16 indicated.

[0074] In the Figures 17 and 18An example of the additional layer element "chromatic tooth neck" is shown. As can be seen, the artificial tooth element is colored in the area of ​​the tooth neck, so that an additional element is arranged. The additional layer element "chromatic tooth neck" 62 can, as can be seen from Fig. 18 As can be seen, the additional layer element 62 can be arranged at least partially within the core element 38. This is defined in particular by the location of the interface 53. The additional layer element "chromatic tooth neck" is preferably delimited by the outer contour of the outer layer element 50. It is also possible for the additional layer element "chromatic tooth neck" 62 to be arranged partially within the outer layer to change the optical appearance, so that the outer layer element 50 covers the additional layer element "chromatic tooth neck" 62 with a possibly thin layer.

[0075] In another in Fig. 19The schematically illustrated additional layer element is the "Translucency Effect" 64 additional layer element. This is an additional layer element that is provided in the incisal edge area of ​​the artificial tooth element within the outer layer element 50. To define the position and design of the "Translucency Effect" 64 additional layer elements, control points can be defined on an upper surface of the outer layer element, which are then moved inward, i.e., toward the inner core element.

[0076] In a preferred embodiment, the outer boundary of the additional layer element “translucency effect” represents the outer surface of the outer layer element 50.

[0077] In another case, particularly in Fig. 20The additional layer element "horizontal band" 66 shown is a horizontal line located approximately in the central region of the artificial tooth element. The horizontal band preferably extends from a horizontal line 68 located approximately at the height of the center of the tooth element. In cross-section, the horizontal band 66 can be elliptical. In particular, the horizontal band 66 extends partially into the outer layer element 50 and is partially located within the inner partial element 38.

[0078] With an additional layer element ( Fig. 21) is the additional layer element "surface effect" 70. This is arranged in a front area of ​​the artificial tooth element, preferably between the core element 38 and the outer layer element 50. If there is an overlap in the vertical direction between the additional layer element "surface effect" 70 and the additional layer element "accentuation of mamelons" 60, the additional layer element "surface effect" can be arranged relative to a front side 72 of a Fig. 1 The incisor shown can be arranged in front of or behind the additional layer element "Accentuation Mamelons" 60.

[0079] To carry out and in particular to at least partially automate the method according to the invention, a virtual network ( Figures 23 to 24). The virtual mesh has, in particular, equidistantly arranged horizontal lines 74 and vertical lines 76. The outer boundary of the mesh is the outer contour silhouette 78 of the artificial tooth element. Nodes 80 can be defined by points of contact of the vertical and horizontal lines 74, 76 with the outer contour silhouette. Wide nodes 82, see for example Fig. 24 , can be defined at the intersection points of the horizontal and vertical lines 74, 76.

[0080] With the help of the individual nodes 80, 82, the arrangement, alignment, size, etc. of the individual additional layer elements can be defined and adjusted in a simple manner, in particular automatically.

[0081] For example, the nodes 80 arranged on the silhouette 78 can be used for the translucency effect by individual points, as shown in Fig. 23 visible, be postponed.

[0082] Nodes 82 can, for example, Fig. 24 As can be seen, these nodes can be used to define the position of the surface effect. Other nodes can be used to define the remaining additional layer elements.

Claims

1. Computer-implemented method for defining different layer elements of an artificial tooth element comprising the steps of: determining a three-dimensional, outer contour of the artificial tooth element, defining an interface between an inner core element (38) and an outer layer element (50) which surrounds the inner core element (38) at least in part, characterized by the further steps of selecting at least one additional layer element (60, 62, 64, 66) from a provided selection list containing a plurality of additional layer elements, which includes: accentuation of mamelons, wherein when selecting the additional layer element "accentuation of mamelons", the additional layer element (50) "accentuation of mamelons" is automatically arranged at the core element in the region of a mamelon defined by the interface, wherein the additional layer element "accentuation of mamelons" is arranged at the core element (38) in the region of the at least one, preferably all mamelons defined by the interface and an additional layer element "accentuation of mamelons" is arranged which at least partly surrounds the at least one, preferably all mamelons defined by the interface, and automatically arranging the at least one selected additional layer element (60, 62, 64, 66) in spatially defined relation to the core element (38).

2. Method according to claim 1, characterized in that the selection list further includes the following additional layer elements: chromatic tooth neck and / or translucence effect and / or halo effect and / or horizontal band and / or surface effect, and wherein, when selecting one of these additional layer elements, the selected additional layer element (60, 62, 64, 66) is automatically arranged in spatially defined relation to the core element (38) and / or the outer layer element (50).

3. Method according to one of claims 1 or 2, in which a material and / or a color can be selected at least for individual additional layer elements (60, 62, 64, 66).

4. Method according to claim 3, characterized in that the additional layer element "accentuation of mamelons" is arranged at least partly within the outer layer element (50).

5. Method according to one of claims 3 or 4, characterized in that for forming the additional layer element "accentuation of mamelons", the interface at at least one mamelon is displaced in particular incisally, wherein control points of at least one mamelon, which are defined in particular by height points, are displaced incisally, wherein the additional layer element "accentuation of mamelons" is formed preferably in the region between the interface prior to and after the displacement and / or the displacement is 0 to 1.0 mm, in particular 0 to 0.7 mm.

6. Method according to one of claims 1-5, in which, when selecting the additional layer element "chromatic tooth neck", a material is at least partly colored in a region of the outer layer element located apically with respect to a boundary curve.

7. Method according to one of claims 1-6, in which, when selecting the additional layer element "chromatic tooth neck", the outer layer element (50) is replaced at least partly with the additional layer element "chromatic tooth neck" in a region located apically with respect to a boundary curve and / or in which the outer contour of the additional layer element "chromatic tooth neck" is limited by the outer contour of the outer layer element (50).

8. Method according to one of claims 1-7, in which, when selecting the additional layer element "incisal / occlusal optical effect", which includes in particular the additional layer element "translucence effect" and / or the additional layer element "halo effect", the additional layer element "incisal / occlusal optical effect" is arranged within the outer layer element (50) in an incisal edge region of the artificial tooth element.

9. Method according to claim 8, in which the additional layer element "incisal / occlusal optical effect" is limited by the outer contour of the outer layer element (50) and / or in which, for the definition of the additional layer element "incisal / occlusal optical effect", control points defined on the surface of the outer layer element (50) are displaced apically, wherein the displacement occurs preferably along a normal to the surface of the outer layer element (50).

10. Method according to claim 8 or 9, in which a displacement by 0 to 1 mm, in particular 0 to 0.5 mm occurs and / or in which the additional layer element "incisal / occlusal optical effect" is formed in the region between the surface prior to and after the displacement and / or in which the outer contour of the additional layer element "incisal / occlusal optical effect" is limited by the outer contour of the outer layer element (50).

11. Method according to one of claims 1-10, in which, when selecting the additional layer element "horizontal band", a horizontal centre line is defined and the additional layer element "horizontal band" is arranged between the core element (38) and the outer layer element (50) in the region of the centre line, wherein the additional layer element "horizontal band" protrudes into the core element (38) and / or the outer layer element (50), wherein the additional layer element "horizontal band" preferably comprises an incisal / apical dimension from 0.3 to 2 mm and / or a depth from 0.2 to 1.5 mm.

12. Method according to one of claims 1-11, in which, when selecting the additional layer element "surface effect", the additional layer element "surface effect" is arranged on the interface in a front region. wherein, preferably, the additional layer element "surface effect" partly overlaps with the additional layer element "accentuation of mamelons", wherein the additional layer element "surface effect" preferably has a width of 1 to 8 mm, a height of 1 to 10 mm and a depth of 0.1 to 1 mm.

13. Method of claim 12, characterized in that the additional layer element "surface effect" is arranged in the core element (38) and / or in the outer layer element (50) and is limited in particular by the outer contour of the outer layer element (50).

14. Method according to one of claims 1-13, in which, for an automatic definition of control points, a virtual grid is applied on the surface of the outer layer element (50), wherein the vertical and the horizontal dimension of the grid is defined by the maximum dimension of the outer contour silhouette, wherein the grid preferably comprises a plurality of vertical and / or horizontal lines that divide the tooth contour in particular equidistantly.

15. Method according to claim 14, characterized in that the intersection points of the horizontal and vertical lines define the control points (82) and / or in which control points (80) are defined at intersection points of the vertical and / or horizontal lines and an outer contour silhouette.