DE102021122356B3 - Method and device for the automated selection of restorative materials for the restoration of a tooth - Google Patents

Abstract

The invention relates to a method for the automated selection of restoration materials (R) for a restoration element (E) for the restoration of a tooth (Z), the method comprising the steps:
a) Provision of material data (WD) on color-determining properties of a plurality of restoration materials (R),
b) providing or recording geometry data (GD) on the 3D geometry of a tooth area (B) to be simulated and a plurality of color data (D),
c) Creation of a virtual tooth model (M) at least of the tooth area (B) using the geometry data (GD) and material data (WD),
d) simulation of color-characterizing simulated color data (SD) of the tooth model (M), based on the distribution of the restoration materials (R) in the tooth model (M), and the corresponding material data (WD) from the database,
e) Comparison of the simulated color data (SD) of the tooth model (M) with the color data (D),
f) At least in the case in which the comparison is outside a predetermined quality range: repeating steps c) to f) up to a predetermined termination criterion,
g) Selection of a result model (EM) from the number of created tooth models (M),
h) Output of output data (AD) containing information which enable a restoration element (E) to be produced in accordance with the result model (EM).
The invention also relates to a corresponding device and a dental device.

Description

The invention relates to a method and a device for the automated selection of restoration materials for the production of a restoration element for the restoration of a tooth. In particular, the invention relates to a method and a device for the automated determination of restoration materials for a highly aesthetic restoration of a tooth, taking into account the entire tooth geometry. The invention also relates to a dental device.

The term "dentures" is used for any form of replacing missing natural teeth and is used to produce facial aesthetics as well as speaking and chewing performance. A distinction is made between fixed dentures, such as crowns, partial crowns and bridges, and removable dentures, such as full dentures and partial dentures. There is also a combined denture that consists of a fixed part and a removable part. Dentures can be used to create a complete tooth, e.g. in the form of a crown, or just a part of a tooth, e.g. in the form of a partial crown, an inlay or an onlay.

The forms and possible uses are manifold. If, for example, an entire tooth is to be replaced or restored, an implant can be anchored in the jaw and attached to it as a superstructure in the form of a crown, or a bridge or prosthesis anchor, which is usually done by means of screwing, cementing or bonding. If only part of a tooth is missing, this part can be replaced with a partial crown, inlay or onlay. This element is usually glued or cemented.

In addition to dentures, there are also the well-known fillings, which are usually made directly in the mouth using plastic materials.

For aesthetic reasons, care is often taken to ensure that the denture or filling has the same color as the former tooth or the adjacent teeth. Nowadays, color samples are usually used for this purpose, which are held next to a tooth and the color of the tooth is thus determined by looking at the tooth and tooth sample (color scale). In addition to this most common type of color determination, there are also probe-based, point-based or camera-based, imaging devices that determine the pure color information from a unidirectional view using colorimetric color measurement and assign it to a color scale.

In the manufacture of dentures, prefabricated blanks are often used, which have a defined, inhomogeneous (usually slightly iridescent) color distribution. A dental prosthesis is milled out of such a blank after the expert has determined the optimal location (position and orientation) in the blank for its known shape. The position ultimately determines the color impression of the dental prosthesis and results from the experience of the person skilled in the art when specifying the position.

US 2020/0 397 534 A1 describes an information-sharing platform where on-site restorative technology dentists can share their design, supplies, knowledge, and free time quotas with local dentists. Such a platform, especially for shade measurements, block selection and characterization recommendations, serves dentistry as a resource to improve shade matching in dental restorations.

US 2020/0 315 761 A1 relates to a system with a dental blank and an associated shade guide. The dental blank has an uneven color shade, and the color scale has several color samples with certain color shades that partially correspond to the color shade of the dental blank. The invention is for the production of a tooth restoration having a shade that resembles the shade of a natural tooth.

US 2020/0 000 563 A1 discloses a computer program for specifying a material color for a tooth restoration. When specifying the material color of the tooth restoration, the material color of the restoration material is changed based on a target tooth color. This change is based on parameters such as the color of a die or an abutment, the restoration layer thickness, the type of restoration and the processing technique. The specification of the material color of the restoration is then controlled by the computer program.

EP 3 650 821 A1 is concerned with a system and method for determining the color of teeth or tooth surfaces, the system comprising a camera with an attachment that adjusts the geometry of a captured image such that, compared to a recording without an attachment, the distance, the spatial Angle and orientation of the tooth surfaces relative to the camera are restricted.

An automated determination of the natural color impression of the tooth, which is determined not only by the pure tooth color but also by the translucency and light propagation in the tooth and therefore for the observer also depends on the viewing direction and lighting has not been possible up to now. However, this would be necessary for the automated production of highly aesthetic, nature-identical dentures. A nature-identical determination and restoration of the tooth color impression would also be of great aesthetic advantage for direct filling therapy with plastic filling materials. From an optical point of view, a tooth is a medium that scatters and absorbs in volume. Due to the translucency of tooth tissue, a simple color measurement is heavily dependent on the geometry of the tooth and the lighting and detection geometry.

The object of the present invention was to overcome the disadvantages of the prior art and to provide a method and a device for the automated selection of restorative materials for a restoration of a tooth (a denture or a direct filling therapy for the restoration of a tooth) by means of which an automated definition of the color impression, in particular an automated restoration of a tooth, or production of a restoration element (denture or a filling) and possibly a control of the restoration success can be achieved. In particular, one object of the invention is to automate and optimize positioning of a dental prosthesis in a restoration material and/or selection of the restoration material, taking into account the translucency, and thus to make the currently very manual workflow more effective and reproducible. In particular, the object of the invention is to create an optimal restoration element easily and automatically by means of 3D printing, to provide an automated option for milling out a blank or to specify a specification for adding color-determining materials to denture materials or filling materials.

This object is achieved by a method and by a device and a dental device according to the independent claims.

First of all, it should be noted that the term “restorative material” within the meaning of the invention can basically mean all materials with which a tooth can be restored or replaced, ie denture materials or materials for the filling. The term "restoration" relates to the restoration (of a tooth) and the term "restorative element" relates to the object of restoration, namely fixed dentures, removable dentures and fillings. These are in particular crowns, partial crowns, inlays, onlays, bridges, full dentures and partial dentures. A denture or filling can be made of solid materials, powders or pastes. A dental prosthesis referred to here can be manufactured outside the mouth or the restoration of a tooth can be carried out inside the mouth as part of the direct filling therapy.

1. a) Bereitstellen von Werkstoffdaten zu optischen, farbbestimmenden Eigenschaften einer Mehrzahl von Restaurationsmaterialien,
2. b) Bereitstellen oder Aufnahme von Geometriedaten zur 3D-Geometrie (zumindest) eines nachzubildenden Zahnbereichs und einer Mehrzahl von farbcharakterisierenden (realen) Farbdaten des Zahns (insbesondere des Zahnbereichs),
3. c) Erstellung eines virtuellen Zahnmodells zumindest des Zahnbereichs aus den Geometriedaten, wobei das Zahnmodell aus einer Verteilung einer Anzahl der Restaurationsmaterialien aufgebaut ist, deren Werkstoffdaten in der Datenbank enthalten sind,
4. d) Simulation von farbcharakterisierenden (simulierten) Farbdaten des Zahnmodells, basierend auf der Verteilung der Restaurationsmaterialien im Modell und den entsprechenden Werkstoffdaten aus der Datenbank, wobei die simulierten Farbdaten so beschaffen sind, dass sie mit den (realen) Farbdaten verglichen werden können,
5. e) Vergleich der simulierten Farbdaten des Zahnmodells mit den (realen) Farbdaten, wobei jeweils entsprechende Bereiche des Zahns und des Zahnmodells verglichen werden,
6. f) Zumindest in dem Fall, in dem der Vergleich außerhalb eines vorbestimmten Qualitätsbereichs liegt: Wiederholung der Schritte c) bis f) bis zu einem vorbestimmten Abbruchkriterium, wobei bei jeder Wiederholung ein neues virtuelles Zahnmodell erstellt wird,
7. g) Auswahl eines Ergebnismodells aus der Anzahl der erstellten Zahnmodelle,
8. h) Ausgabe von Ausgabedaten, die Informationen enthalten, welche eine Herstellung eines Restaurationselements (Zahnersatz oder Füllung) entsprechend dem Ergebnismodell ermöglichen,
9. i) (optional) Fertigung eines Restaurationselements (den Zahnersatz oder die Füllung) unter Verwendung der Ausgabedaten.

The method according to the invention serves for the automated selection of restoration materials for the restoration of a tooth and preferably also for the production of a restoration element (denture or filling). The procedure includes the following steps:

1. a) Provision of material data on optical, color-determining properties of a large number of restoration materials,
2. b) providing or recording geometry data on the 3D geometry of (at least) a tooth area to be simulated and a plurality of color-characterizing (real) color data of the tooth (in particular of the tooth area),
3. c) Creation of a virtual tooth model, at least of the tooth area, from the geometric data, the tooth model being constructed from a distribution of a number of the restoration materials whose material data are contained in the database,
4. d) Simulation of color-characterizing (simulated) color data of the tooth model, based on the distribution of the restoration materials in the model and the corresponding material data from the database, with the simulated color data being such that they can be compared with the (real) color data,
5. e) Comparison of the simulated color data of the tooth model with the (real) color data, corresponding areas of the tooth and the tooth model being compared in each case,
6. f) At least in the case in which the comparison is outside a predetermined quality range: repeating steps c) to f) up to a predetermined termination criterion, with a new virtual tooth model being created with each repetition,
7. g) Selection of a result model from the number of created tooth models,
8. h) Output of output data containing information that enables a restoration element (denture or filling) to be produced in accordance with the result model,
9. i) (optional) fabrication of a restorative element (the denture or filling) using the output data.

An important prerequisite for the method according to the invention is that the color-determining ends, optical properties of the materials ("restoration materials") are known, which can be used for the production of the restoration element. Since the invention ultimately depends on the color impression, at least properties should be known, such as the effective scattering coefficient and/or the absorption coefficient and/or the refractive index of the respective materials. These properties are preferably available in a database as material data and are available to the method (in particular for simulation). The method simply accesses the material data in the database, for example. The material data can be obtained using known Methods are determined, for example, using an integrating sphere measuring method, a measurement of a spatially resolved remission, a measurement of a time-resolved remission, a fringe projection or an ellipsometer, but other methods are also possible.Calculation or the use of simulated data is also possible t possible. It is preferred that the material data contain data with which the color data can be generated by means of a simulation.

It is clarified that different restoration materials can mean fundamentally different materials as well as materials in which the base material or matrix material is the same, but the color appearance is changed by the addition of other materials, such as pigments, which change the optical properties of the base material, e.g. its scattering and absorption properties, vary.

The tooth that is to be replaced or restored is naturally known. However, it is possible that the tooth or the relevant part of the tooth itself is no longer there, for example because it was lost or destroyed in the course of an intervention. The procedure therefore assumes a “tooth area to be reproduced”. The tooth area is a volume of the tooth in question. The "tooth area to be simulated" is the volume that is to be restored by the restoration element.

The tooth area to be reproduced can be a complete tooth crown (e.g. for an implant) or a part of a tooth crown, which should be covered with a partial crown or closed with an inlay. Since the method according to the invention is intended to improve the color impression, it is preferred that the tooth area includes an outer surface of the tooth, but this is not absolutely necessary since a tooth, as mentioned above, has a certain translucency, and materials almost completely surrounded by tooth material also have the affect the color impression of the tooth.

At least the geometry data of the tooth area to be simulated and optimally the (real) color data of the tooth area are required for the method. With this data, at least the tooth area (in particular the entire tooth) can be simulated in terms of color and shape (in particular also its surface roughness).

The geometry data include the 3D geometry of at least the tooth area to be simulated. You can correspond exactly to the tooth area to be reproduced, i.e. specify its shape and thus also specify what the restoration element should look like. However, they can also include other areas of the tooth. It is advantageous for the method if the geometry data include the entire tooth, at least its visible parts, and preferably also specify the tooth area to be simulated. In addition, the geometry data can also include information about the surface roughness of the tooth. This surface roughness influences the angle-resolved reflection on the tooth surface and thus also the color impression of a tooth area to be simulated. Since light from the part of the tooth to be restored can also penetrate into neighboring areas (gingiva, periodontium, bone, neighboring teeth, underlying structures such as e.g. implant abutment) and/or from there into the tooth, knowledge of those neighboring structures and geometries is also important advantageous.

The color data include color-characterizing information about the tooth or the tooth model. The color data may preferably represent a color space, e.g., a CIE color space such as RGB (Red-Green-Blue). In a simple case, it is sufficient if the visible color of the respective point on the tooth is clearly defined by the color data. Furthermore, color data can preferably reflect remission values of the measurements with structured lighting, e.g. with different spatial frequencies. In this respect, the color data can also contain the data to be determined with regard to translucency, absorption and scattering. In general, the color data can contain only a few spectrally resolved values (such as RGB) or also many (multispectral) or very many (hyperspectral) spectrally resolved values. For example, a digital color image of a tooth would provide sufficient color data for at least the displayed side.

In the text, a distinction is made between color data that originates from the real tooth or relates to the real tooth and the simulated color data that is based on the tooth model. The former are the "normal" color data and are specially marked in the text with the addition "real" (in brackets) for better understanding. It could also be referred to as "measurement data" if it has been measured, or as "color data". In contrast to this, the simulated color data refer to the (virtual) tooth model and were generated using the simulation. In order for a comparison to be possible, the (real) color data and the simulated color data should be of the same nature, which is reflected in the use of the same term "color data".

Although theoretically the color data from a single location of the tooth or tooth model can be used, it is preferable to specify color data from multiple locations. Good results can already be achieved if color-characterizing data from three different locations in the tooth area are available as color data. However, it is beneficial when there is color data from many more than three locations. Basically, the more color data there is, the better the result of the comparison with the simulation.

Since the (real) color data between the locations can also be interpolated, it is not absolutely necessary for (real) color data to be available from the tooth area to be reproduced. (Real) color data can also be present around this tooth area and the color of the tooth area to be simulated can be interpolated from this (real) color data.

As mentioned, it should be noted that the tooth area to be reproduced does not always have to exist in reality (see above). Therefore, the (real) color data does not necessarily have to come from the tooth area to be simulated (because it may not necessarily be possible to measure it there), but can also come from the rest of the tooth or from neighboring teeth. They can also be completely simulated or specified manually (e.g. using a color model). The main thing for the procedure is that it is digital data and allows conclusions to be drawn about the color of the tooth (at least its visible part) and thus also the tooth area to be reproduced. The (real) color data therefore contain in particular data on the color impression of a tooth area, which at least includes the tooth area to be simulated or even includes the entire visible area of the tooth. Mind you, this means the undestroyed tooth, without a missing tooth area to be reproduced, i.e. a tooth as it was before a dental intervention or as it should be again in the future.

For example, a fringe projection (or generally structured illumination such as a point pattern) can be used to record the 3D geometry and to determine the (real) color data of a tooth area. However, homogeneous illumination can also be used to determine the (real) color data, in which case the illumination and detection geometry and the 3D geometry of the tooth area should be precisely known. A preferred measurement setup includes a multispectral light source (in the simplest case RGB or white light), a digital projection unit for projecting strips onto the tooth (area), objective lenses for illumination and for detection and a multispectral image sensor, e.g. a digital CMOS or CCD camera. When using white light, an RGB camera should be used, with a tunable light source, a monochrome camera is basically sufficient.

A key part of the method is the creation of a virtual tooth model, which is a virtual model of a tooth or a tooth area and includes at least part of the tooth area to be simulated (preferably at least the complete tooth area to be simulated). In addition to a complete tooth, a tooth model could in particular also be understood as a crown, a partial crown, an inlay or another part of a tooth to be restored or added. Because of the difficulties indicated above in the automated determination of the color impression of a tooth, it is advantageous if the tooth model represents at least the complete visible part of the tooth.

When the tooth model is created, at least the tooth area, but preferably the entire tooth, is modeled from the geometric data. It is important here that the tooth model is made up of a distribution of a number of the restoration materials. This means that in the volume, which is defined by the geometry data, it is clearly defined which material or which material mixture is present at which point on the tooth model. The entire volume of the tooth model should be "filled" with material (but this is not absolutely necessary). Specifically, the term "distribution of restorative materials" or equivalent means that either the tooth may consist of a single restorative material or multiple restorative materials may be present at different (but clearly defined) locations, and additionally preferably that a number of restorative materials are also in one color (clearly defined) altered form at clearly defined locations. The latter is explained in more detail below. A distribution can also in particular be a mixture of two or more different restoration materials or one Include mixing a restorative material with another material.

A virtual model of a tooth is thus obtained, with the optical properties of the tooth model being uniquely determined at each point by the material data from the database and the known distribution of the restoration materials. The tooth model can be created automatically or manually. In this case, it is particularly preferred to create the tooth model automatically, but to offer a user the possibility of manual creation, e.g. through the possibility of manually defining the position of the tooth model within (a model) of a given blank.

Once the tooth model has been determined, the simulated color data can be simulated. As stated, the simulated color data are color-characterizing data like the (real) color data and should correspond to the (real) color data in terms of type.

Since the tooth model is based on a distribution of the restoration materials and their material data are known, the simulated color data can be determined from the tooth model. Basically, the simulated color data reflects what color impression the tooth model would have with a defined illumination and detection geometry.

In order to obtain a good comparability of (real) color data and simulated color data, it is advantageous if corresponding prerequisites are assumed in the simulation, as they existed for obtaining the (real) color data. This preferably includes the direction of the illumination and/or the direction of the recording. The best results are obtained when the simulation is based on identical lighting and exposure as was used to obtain the (real) color data of the tooth area. In the event that the optical data of the tooth area were not measured, but rather estimated or calculated, it could be determined (e.g. by a separate simulation) how the real tooth would look with a given lighting and recording position (then corresponds to the (real) color data ) and an identical configuration of lighting and recording position can be used in the simulation. In a very simple case, the (real) color data can simply contain information about which part of the tooth has which optical properties and the simulated color data, which part of the tooth model has which optical properties.

Since, as mentioned above, a tooth appears to have a slightly different coloring from different viewing angles, this preferred procedure of selecting the same or similar lighting and viewing angles when measuring and simulating the color data is particularly advantageous for the result. If color data of the tooth should be available from a number of different lighting and/or viewing angles, it is also preferable for this to be simulated accordingly in the simulation (these different lighting and/or viewing angles also being simulated). It is also preferable that a number of viewing angles and a number of lighting angles are simulated during the simulation and then a lighting position and a viewing angle that match the real view are finally selected.

After the simulation, the simulated color data and the (real) color data are compared. This can be achieved, for example, simply by calculating differences in the color space of corresponding points (e.g. pixels) of the tooth area and the tooth model. Corresponding areas of the tooth area and the tooth model are compared in each case, with “corresponding areas” meaning the points that are identical or at least corresponding in terms of their geometric position in the tooth area and tooth model.

The comparison provides information about the quality of the tooth model. If the color impressions (simulated and real color data) are very similar, the quality is good, if they are dissimilar, then the quality is bad. A limit range can be defined as the quality range, which, for example, includes a field with limit values for the differences mentioned above. However, the quality range can also simply be a single value (e.g. ΔE) that a specified proportion of the differences must not exceed. However, the quality domain can also be a more complex construct, e.g. a vector space.

If the comparison is outside the quality range, i.e. the color impression between the tooth model and the tooth area is dissimilar, a (different) tooth model is created, simulated color data is determined on this and these are compared again with the (real) color data until a good color similarity is achieved (or another predetermined termination criterion is reached). It is preferred that other tooth models always have the same shape as the first tooth model but have a different distribution of restoration materials.

A result model is selected from the tooth models. This should be the one where the simulated color data and (real) color data were most similar to each other or where the color impression between the tooth model and the tooth area is most similar. In practice, the result could The model should be the one with the smallest (on average) differences between simulated color data and (real) color data.

If the result model is selected, output data is output. This output data can be of the most varied nature, but must always contain information that enables a restoration element to be produced in accordance with the result model. This can be, for example, the position (this term always means position and orientation) of a denture as a restoration element in a given blank from which the denture is milled. However, the output data can also contain the exact distribution of the restoration materials for a layer-by-layer or voxel-by-voxel structure and in particular also print data for 3D printing, preferably which material is to be used in each volume element of the 3D printing. It should be noted that this print data can preferably contain information about the materials available from the 3D printer used for typically millions of different voxels, which together represent the restoration element. With this print data and the known material data of the materials used, the (simulated) color data can be calculated on the basis of the simulations for light propagation mentioned and compared with the (real) color data.

The output data can also include a graphical representation of the result model, in particular together with a graphical representation of the tooth area.

In this regard, the method can offer a user the possibility, after viewing the result model, in particular by comparing it with the representation of the tooth area, to go through steps c) to f) again with a different tooth model that has been created by the user, in particular manually .

Finally, the restoration element can also be manufactured afterwards, e.g. by automated milling from a given blank or by means of 3D printing processes or automated filling processes. In this case, the output data preferably includes data for the respective manufacturing process, e.g. CNC data or print data.

Very good results are obtained if the information of a (entire) measurement setup, as used to obtain the (real) color data, is integrated in the simulation, i.e. the same conditions for the simulation of the simulated color data (as exactly as possible) as for the measurement of the (real) color data. This means that as far as possible all the rays of the illumination and as far as possible all the camera rays should be known, which can be implemented using a calibration. A calibration is preferably carried out by performing a one-time calibration of the phase space by measuring known structures (e.g. point patterns) before a measurement, e.g. with a dental scanner or a setup for measuring structured illumination. Based on this measurement, the beam paths from the lighting unit to the tooth and from there to the detector can then be determined. Such a calibration in connection with a simulation (e.g. a Monte Carlo simulation) then makes it possible to generate synthetic data (simulated color data) of a tooth model. With the help of the simulation, the measured (real) color data can then be compared with the simulated color data of the tooth model, as described, based on the optical properties of the restoration materials. If necessary, the materials within the object are adjusted and a new simulation is carried out until the color values match those of the measurement as well as possible.

In order to be able to compare the measured color data, the simulation geometry should largely correspond to the measurement geometry. This means that the target geometry of the restoration element, e.g. the crown to be manufactured, should roughly match the measured geometry of the tooth. This is usually possible by measuring a corresponding tooth, e.g. using a 3D topography measurement, e.g. with a strip projection or using other intraoral scanners. The object is then aligned with regard to the lighting and camera. For example, a triangular mesh of the simulation object can be brought into agreement with a point cloud resulting from the measurement by rotation and translation. This is very advantageous, since a correct radiation and detection geometry can then be achieved, with which a good quantitative comparison of the color values is possible in practice due to the translucency of the tooth.

• - eine Datenbank umfassend Werkstoffdaten zu optischen, farbbestimmenden Eigenschaften einer Mehrzahl von Restaurationsmaterialien,
• - eine Dateneinheit ausgelegt zum Bereitstellen oder Aufnahme von Geometriedaten zur 3D-Geometrie eines nachzubildenden Zahnbereichs und einer Mehrzahl von farbcharakterisierenden (realen) Farbdaten des Zahns,
• - eine Modellierungseinheit ausgelegt zur Erstellung eines virtuellen Zahnmodells zumindest des Zahnbereichs aus den Geometriedaten, wobei das Zahnmodell aus einer Verteilung einer Anzahl der Restaurationsmaterialien aufgebaut ist, deren Werkstoffdaten in der Datenbank enthalten sind,
• - eine Simulationseinheit ausgelegt zur Simulation von farbcharakterisierenden simulierten Farbdaten des Zahnmodells, basierend auf der Verteilung der Restaurationsmaterialien im Zahnmodell, und den entsprechenden Werkstoffdaten aus der Datenbank, wobei die simulierten Farbdaten so beschaffen sind, dass sie mit den (realen) Farbdaten verglichen werden können,
• - eine Vergleichseinheit ausgelegt zum Vergleich der simulierten Farbdaten des Zahnmodells mit den (realen) Farbdaten, wobei jeweils entsprechende Bereiche des Zahns und des Zahnmodells verglichen werden,
• - eine Auswahleinheit ausgelegt zur Auswahl eines Ergebnismodells aus der Anzahl der erstellten Zahnmodelle,
• - eine Ausgabeeinheit ausgelegt zur Ausgabe von Ausgabedaten, die Informationen enthalten, welche eine Herstellung eines Restaurationselements entsprechend dem Ergebnismodell ermöglichen.

A device according to the invention for the automated selection of restoration materials for a restoration element for restoring a tooth is preferably designed for carrying out a method according to the invention. The device includes the following components:

• - a database comprising material data on optical, color-determining properties of a large number of restoration materials,
• - A data unit designed to provide or record geometry data for the 3D geometry of a tooth to be simulated Reichs and a plurality of color-characterizing (real) color data of the tooth,
• - a modeling unit designed to create a virtual tooth model of at least the tooth area from the geometric data, the tooth model being constructed from a distribution of a number of the restoration materials whose material data are contained in the database,
• - a simulation unit designed to simulate color-characterizing simulated color data of the tooth model, based on the distribution of the restoration materials in the tooth model, and the corresponding material data from the database, the simulated color data being such that they can be compared with the (real) color data,
• - a comparison unit designed to compare the simulated color data of the tooth model with the (real) color data, corresponding areas of the tooth and the tooth model being compared in each case,
• - a selection unit designed to select a result model from the number of tooth models created,
• - an output unit designed to output output data containing information which enable a restoration element to be produced in accordance with the result model.

• - eine Projektionsvorrichtung ausgelegt zum Einstrahlen von Licht auf einen Zahn,
• - einen Bildsensor, insbesondere eine Kamera, ausgelegt zum Erfassen von Licht, welches aus der Position des Zahnes stammt, und
• - eine Ermittlungseinheit ausgelegt zur Bestimmung einer Vielzahl von farbcharakterisierenden (realen) Farbdaten unterschiedlicher Bereiche des Zahns aus den vom Bildsensor detektierten Lichtstrahlen, und bevorzugt auch von Geometriedaten zur 3D-Geometrie des Zahns.

A dental device according to the invention comprises a device according to the invention. The dental device preferably additionally comprises

• - a projection device designed to radiate light onto a tooth,
• - an image sensor, in particular a camera, designed to detect light originating from the position of the tooth, and
• a determination unit designed to determine a large number of color-characterizing (real) color data of different areas of the tooth from the light beams detected by the image sensor, and preferably also geometry data for the 3D geometry of the tooth.

Light originating from the position of the tooth is preferably light from the projection device which was reflected, transmitted or remitted. However, this also means light that does not come directly from the projection device, but e.g. from a fluorescence of the tooth excited by light from the projection device. Basically, the image sensor is designed and positioned to capture an image of the tooth with light coming directly or indirectly from the projection device.

According to a preferred method, the material data include information on spectral scattering properties and/or spectral absorption properties and/or spectral refractive indices and/or the surface roughness of the restoration materials. Using this data, a color impression can be determined objectively and unambiguously. In this regard, the material data preferably includes data on the scattering coefficient and/or on the phase function (also called scattering function) and/or on the absorption coefficient and/or on the refractive index of the corresponding material. It is preferred that the simulated color data is simulated by means of calculations based on the optical scattering and absorption properties and in particular also on the refractive index from the material data of the restoration materials. The relevant calculations are well known to those skilled in the art. For example, the incidence of white light can be simulated and the color of a resulting light beam can be determined from the white spectrum, taking into account the spectrally resolved variables, scattering coefficient and phase function and absorption coefficient and refractive index. Depending on the application, the complex refractive index or just its real part can be used as the refractive index.

According to a preferred method, the (real) color data are determined by means of a spectrally resolved measurement of light, which originates from the position of the tooth, in particular the tooth area, in particular based on remission and/or reflection and/or transmission and/or Fluorescence. This can be achieved simply by measuring the corresponding light produced. In this case, a defined illumination and/or detection geometry is preferably used. In this case, the simulation of the simulated color data is preferably carried out in such a way that the same alignment of the tooth model relative to the illumination and/or to the detection as in the real recording of the tooth is simulated during the simulation. In this case, the (real) color data and particularly preferably also the geometry data are preferably obtained by means of structured illumination, in particular by means of strip-shaped illumination. The technique of obtaining geometric data from structured (in particular strip-shaped) illumination is known in the prior art and is based on triangulation. However, the (real) color data can also be obtained from a homogeneous illumination.

It is noted here once again that both the (real) color data are always color-characterizing, since a color impression is to be compared.

According to a preferred method, a restoration element is automatically produced based on the output data, or the output data include information by means of which automated production of the restoration element is possible, with the restoration element preferably being built up in layers or voxels, in which a layer of a restoration material or a mixture of Restorative materials in the form of a powder, liquid or paste are introduced into a build-up area, solidified and then a number of further such layers are applied in this way on top of the respective last solidified layer, the arrangement of the restorative materials being according to the output data.

The structure is preferably in the form of a 3D print or in the form of a solidification of plastic materials in the mouth.

According to a preferred method, data from a predetermined body of material with a defined distribution of a number of restoration materials are additionally used to create the virtual tooth model. The body of material is in particular a blank and is made up of the restoration materials listed in the database. In dentistry, discs are often used which, in particular, have a layered distribution of different materials or mixtures of materials (restoration materials). The method is preferably carried out in such a way that a tooth volume based on the geometric data (the volume of the tooth model) is arranged in a virtual model of the material body and the distribution of the number of restoration materials in the material body that prevails there is used for the tooth model. It is therefore determined what the condition of the material body is in the arranged tooth volume and this condition is adopted for the tooth model. For another tooth model, the tooth volume is preferably arranged in a different position than before in the material body (e.g. the blank) so that different tooth models are always created.

According to a preferred method, a plurality of restoration materials are used to create the virtual tooth model, which essentially consist of the same basic material, but include different admixtures of other materials, which give the resulting restoration materials different optical, color-determining properties. Basic materials are types of restoration materials, e.g. ceramic or plastic. Other materials are materials which, when added to the base material, change its optical color-determining properties, e.g. make it darker or lighter or change its scattering properties and refractive index. A tooth model can consist of a single base material, e.g. ceramic or plastic, but have different admixtures of other materials at different points. For the sake of simplicity, two identical base materials, which have different admixtures of other materials, are considered here as different restoration materials.

It is preferred that the material data of the plurality of restoration materials with the different optical, color-determining properties are available in the database. This means that there are a number of restorative materials that have the same base material but different admixtures of other materials. For example, there can be a base material in the form of test specimens with different colors, which are measured and the material data obtained as a result are transferred to the database. The material data of different specimens are thus interpreted as different restoration materials.

Alternatively or additionally, the database can contain material data for a restoration material that corresponds to the base material and additional data for the other materials that indicate the extent to which adding these materials changes an optical, color-determining property of this restoration material. The additional data can, but need not, also be present in the database. In this case, however, it would have to be known how the material data of the restoration material change when a specific further material is added and, moreover, it would preferably also be possible to make statements about the change in the material data with different amounts of admixture. This case therefore assumes that the optical, color-determining properties of a base material can be determined after it has been added and that a simulation is therefore possible.

For an optimal result, when providing or recording the color data, there should preferably be more optical information than data on the color alone. As previously stated, light not only enters a viewer's eye from the surface of the tooth, but enters it it also passes through the tooth or is remitted from regions within the tooth, which leads to the color changing at different viewing angles. The problem can be described in such a way that only the appearance from one direction of illumination and observation can be reproduced with mere color information. However, since a tooth has a slightly different color depending on the viewing angle and/or the angle of illumination, i.e. its color can change due to transmission or remission of light, color information alone is not sufficient for an optimal result. A much more precise or more universal color impression can be achieved by knowing the spectrally resolved absorption properties and scattering properties and the refractive index of different points on the tooth (or the tooth model). The additional knowledge about the tooth can be used to create tooth models.

The creation of a tooth model can be improved with the additional optical data (“optical tooth data”). For this purpose, the optical tooth data are preferably used when creating the virtual tooth model for the distribution of the restoration materials. In particular, for different areas of the tooth model, those restoration materials are used whose material data with regard to optical properties are most similar to the optical properties of the optical tooth data of these areas. It is therefore preferred that the optical tooth data contain spectrally resolved information on the refractive index and/or on scattering properties (scattering coefficient and phase function) and/or on absorption properties. With an initial creation of a tooth model, which already has similar optical properties to the real tooth, good results are already achieved with the first simulations, which can then be further improved by slight variations of the tooth model.

According to a preferred method, optical tooth data of the tooth are also provided or recorded when providing or recording the plurality of color data and the distribution of the number of restoration materials in the tooth model is then based on this optical tooth data (as described above).

Simulated color data are preferably obtained by means of calculations based on the Maxwell theory and its approximations, in particular the radiation transport theory.

• - Es wird eine spektral aufgelöste Lichtausbreitung im Zahnmodell auf Basis der Maxwellgleichungen bzw. deren Approximationen berechnet. Dazu sollten die Werkstoffdaten Informationen enthalten, die solche, im Grunde bekannten, Berechnungen ermöglichen.
• - Es erfolgt eine Berechnung einer spektral aufgelösten Lichtausbreitung im Zahnmodell auf Basis einer Strahlungstransportgleichung, insbesondere mittels Monte-Carlo-Simulationen oder analytischen Lösungen. Dazu sollten die Werkstoffdaten Informationen enthalten, die solche, im Grunde bekannten, Berechnungen ermöglichen.
• - Es erfolgt eine Berechnung einer spektral aufgelösten Lichtausbreitung im Zahnmodell auf Basis einer Näherungslösung der Strahlungstransportgleichung (z.B. Diffusionsgleichung). Dazu sollten die Werkstoffdaten Informationen enthalten, die solche, im Grunde bekannten, Berechnungen ermöglichen.
• - Es erfolgt eine Berechnung einer spektral aufgelösten Lichtausbreitung im Zahnmodell auf Basis einer verallgemeinerten Strahlungstransportgleichung, bei welcher die Wahrscheinlichkeit für Streuung und Absorption nicht mehr nur als exponentiell verteilt angenommen wird. Dazu sollten die Werkstoffdaten Informationen enthalten, die solche, im Grunde bekannten, Berechnungen ermöglichen.
• - Es wird ein lernfähiger Algorithmus zur Simulation verwendet, welcher auf die spektral aufgelöste Lichtausbreitung für eine Vielzahl von unterschiedlichen Zahnersätzen aus unterschiedlichen Werkstoffen trainiert worden ist.
• - Es wird ein lernfähiger Algorithmus verwendet, welcher auf Basis einer Vielzahl von Messungen von farbcharakterisierenden (realen) Farbdaten einer Vielzahl von unterschiedlichen Zahnersätzen aus unterschiedlichen Werkstoffen trainiert worden ist.
• - Es wird eine auf Basis der oben angeführten Theorien zur Beschreibung der Lichtausbreitung, insbesondere der Strahlungstransporttheorie, vorberechnete Tabelle, insbesondere eine Look-up-Tabelle, für eine Vielzahl von Zahnmodellen verwendet.

According to a preferred method, the simulation of the (simulated) color data is performed using calculations based on one or more of the following principles:

• - A spectrally resolved light propagation in the tooth model is calculated on the basis of Maxwell's equations or their approximations. For this purpose, the material data should contain information that enables such calculations, which are basically known.
• - A spectrally resolved light propagation in the tooth model is calculated on the basis of a radiation transport equation, in particular by means of Monte Carlo simulations or analytical solutions. For this purpose, the material data should contain information that enables such calculations, which are basically known.
• - A spectrally resolved light propagation in the tooth model is calculated on the basis of an approximate solution of the radiation transport equation (e.g. diffusion equation). For this purpose, the material data should contain information that enables such calculations, which are basically known.
• - A spectrally resolved light propagation in the tooth model is calculated on the basis of a generalized radiation transport equation, in which the probability of scattering and absorption is no longer assumed to be exponentially distributed. For this purpose, the material data should contain information that enables such calculations, which are basically known.
• - An adaptive algorithm is used for the simulation, which has been trained on the spectrally resolved light propagation for a large number of different dentures made of different materials.
• - An adaptive algorithm is used, which has been trained on the basis of a large number of measurements of color-characterizing (real) color data from a large number of different dental prostheses made of different materials.
• A table, in particular a look-up table, precalculated on the basis of the above-mentioned theories for describing the propagation of light, in particular the theory of radiation transport, is used for a large number of tooth models.

• - Informationen an welcher Position mit welcher Orientierung das Restaurationselement in einem Werkstoffkörper (aus Restaurationsmaterial) angeordnet werden muss,
• - Informationen wie das Restaurationselement aus einem Werkstoffkörper (aus Restaurationsmaterial) ausgefräst werden muss,
• - Informationen zum Aufbau des Werkstoffkörpers (also die Verteilung von Restaurationsmaterial), aus welchem ein Restaurationselement ausgefräst werden soll,
• - Informationen welche Verteilung von Restaurationsmaterialien wo im Restaurationselement vorhanden ist,
• - Druckdaten zum 3D-Druck des Restaurationselements, vorzugsweise welches Material in jedem Volumenelement des 3D-Drucks verwendet werden soll,
• - Informationen zu einer Rezeptur für die Mischung unterschiedlicher Restaurationsmaterialien (z.B. (Glas-)Keramiken oder Kunststoffe),
• - das Ergebnismodell, insbesondere ein virtuelles Bild eines finalen Restaurationselements.

According to a preferred method, the output data includes information on one or more of the aspects presented below, whereby when a restoration element is produced outside the mouth, this term can be understood to mean a dental prosthesis:

• - Information at which position and with which orientation the restoration element must be arranged in a material body (made of restoration material),
• - Information on how the restoration element must be milled out of a body of material (restoration material),
• - Information on the structure of the material body (i.e. the distribution of restoration material) from which a restoration element is to be milled,
• - information on which distribution of restoration materials is present where in the restoration element,
• - Print data for 3D printing of the restorative element, preferably which material to use in each volume element of the 3D print,
• - Information on a recipe for mixing different restoration materials (e.g. (glass) ceramics or plastics),
• - the result model, in particular a virtual image of a final restoration element.

According to a preferred method, a number of differences between the simulated color data and the (real) color data are calculated for the comparison. For this purpose, the relevant data is considered, for example, with regard to light which originates from the position of the tooth or the tooth model (in particular after remission and/or reflection and/or transmission). In this case, quantitative values of the light are preferably determined from different points on the tooth. These values are then contained in the simulated color data relating to the tooth model and in the (real) color data relating to the tooth. Of course, differences are only calculated from corresponding points of the tooth and tooth model.

If steps c) to f) of the method are run through several times, an attempt is made to minimize this difference. This can be done by creating tooth models in such a way that they minimize the difference of all spectral simulated and real color data. Furthermore, the difference between the color space data (such as RGB or Lab) calculated from the spectral simulated and real color data can also be minimized.

The result model is then preferably that tooth model in which the difference was the smallest. If the difference should still be greater than a certain minimum value even after the optimization, it is preferred to output a recommendation for further dental technical post-processing of the restoration element.

• 1 zeigt ein menschliches Gebiss und einen Zahn.
• 2 skizziert ein Dentalgerät mit einer bevorzugten Ausführungsform einer erfindungsgemäßen Vorrichtung.
• 3 zeigt ein Blockschaltbild einer bevorzugten Ausführungsform des Messverfahrens.
• 4 skizziert einen Zahn und ein Zahnmodell.
• 5 zeigt die Anordnung eines Zahnvolumens in einem Werkstoffkörper.

Examples of preferred embodiments of the device according to the invention are shown schematically in the figures.

• 1 shows a human set of teeth and a tooth.
• 2 outlines a dental device with a preferred embodiment of a device according to the invention.
• 3 shows a block diagram of a preferred embodiment of the measurement method.
• 4 sketches a tooth and a tooth model.
• 5 shows the arrangement of a tooth volume in a material body.

1 shows a human set of teeth G, namely that of the lower jaw, without wisdom teeth and a single tooth Z, namely a molar of the set of teeth, in whose enamel and possibly dentin in the tooth area B caries has been removed. There is now a cut-out that is to be closed with a restoration element E, which is also shown here. In this example, it can be assumed that the illustrated tooth area B is the tooth area B to be simulated.

2 outlines a dental device 10 with a preferred embodiment of a device 1 according to the invention. Which for the automated selection of restoration materials R for a restoration element E for the restoration of the tooth Z in 1 could be used. For functions of the dental device 10 and the device 1 see also 3 .

In this example, the dental device 10 is also designed to measure (real) color data D of a tooth Z and, in addition to the device 1, also includes a projection device 11, an image sensor 12 and a determination unit 13.

The projection device 11 is designed for radiating white light onto a tooth Z here. A fringe projection can also be used to record the 3D geometry at the same time. For example, the projection device 11 includes a multispectral light source 20 (in the simplest case RGB or white light), a digital projection unit 21 for projecting strips onto the tooth (area) and an objective lens 22 for the illumination.

The image sensor 12 is a camera here. It is designed to detect light originating from the position of tooth Z (dashed lines). The image sensor 12 can also use a lens arrangement in order to image the tooth Z. The image sensor 12 is preferably multispectral. For example, a digital CMOS or CCD camera can be used. When using white light, an RGB camera should be used, with a tunable light source a monochrome camera is basically sufficient.

The determination unit 13 is designed to determine a large number of (real) color data D, which are derived from different points of the tooth Z from the light beams detected by the image sensor 11 . In this example, he can also determine geometry data GD for the 3D geometry of the tooth Z, e.g. by using a triangulation of the image data with a projection of structured light. In this example, the determination unit 13 supplies both the geometry data GD and the color-characterizing (real) color data D for the device 1.

• Eine Datenbank 2 umfassend Werkstoffdaten WD zu optischen, farbbestimmenden Eigenschaften einer Mehrzahl von Restaurationsmaterialien R.

The device 1 is used for the automated selection of restoration materials R for a restoration element E for the restoration of a tooth Z and is designed here to carry out a method as described in 3 is described. The device 1 comprises the following components:

• A database 2 comprising material data WD on optical, color-determining properties of a plurality of restoration materials R.

A data unit 3, here a data interface 3, which is designed to receive the geometry data GD and (real) color data D.

A modeling unit 4 designed to create a virtual tooth model M from the geometry data GD. The tooth model M is made up of a number of restoration materials R whose material data WD are contained in the database 2 .

A simulation unit 5 designed for the simulation of color-characterizing (simulated) color data SD of the tooth model M, based on the distribution of the restoration materials R in the tooth model M, and the corresponding material data WD from the database 2. The simulated color data SD are generated in such a way that they can be compared to the (real) color data D. In this example, the simulation is carried out in such a way that the tooth model M is arranged like the measured tooth Z, a synthetic light source like the projection device 11, and a virtual camera like the image sensor 12. This gives very easily comparable data .

A comparison unit 6 is designed to compare the simulated color data SD of the tooth model M with the (real) color data D, corresponding areas of the tooth Z and the tooth model M being compared in each case.

A selection unit 7 (part of the comparison unit 6 here) is designed to select a result model EM from the number of tooth models M created.

An output unit 8 is designed to output output data AD containing information that enables a restoration element E to be produced in accordance with the result model EM. Contrary to what is shown in the example, the same data interface 3 that is also used as data unit 3 can also be used as the output unit.

The device could also record the (real) color data and, if applicable, the geometry data directly, e.g. projection device 11, image sensor 12 and determination unit 13 could be part of the device.

3 shows a block diagram of a preferred embodiment of the method for the automated selection of restoration materials R for a restoration element E for restoring a tooth Z.

In step I, material data WD relating to optical, color-determining properties of a plurality of restoration materials R are provided.

In step II, geometry data GD relating to the 3D geometry of a tooth region B to be simulated and a plurality of color-characterizing (real) color data D are recorded from a number of locations on the tooth Z, as is the case, for example, in 2 you can see. However, this data could also simply be provided from a data store.

In step III, a virtual tooth model M of at least the tooth region B is created from the geometry data GD, the tooth model M being composed of a distribution of a number of restoration materials R whose material data WD are contained in the database 2 .

In step IV, there is a simulation of color-characterizing simulated color data SD of the tooth model M, based on the distribution of the restoration materials R in the tooth model M, and the corresponding material data WD from the database 2, the simulated color data SD are such that they can be compared with the (real) color data D. This is, for example, a Monte Carlo simulation in which various virtual light beams are radiated onto the tooth model M and their light paths and absorption are calculated after striking the tooth model M according to the material data WD and the underlying light propagation theory.

In step V, the simulated color data SD of the tooth model M is compared with the (real) color data D, corresponding areas of the tooth Z and the tooth model M being compared in each case.

In step VI, at least in the case in which the comparison is outside a predetermined quality range, steps III to V are repeated up to a predetermined termination criterion, with a new virtual tooth model M being created with each repetition.

In step VII, a result model EM is selected from the number of tooth models M created. The tooth model M with the greatest similarity to the original tooth Z is selected here.

In step VIII, output data AD are output, which contain information that enables a restoration element E to be produced in accordance with the result model EM.

In step IX, a restoration element E is then produced in accordance with the output data AD from the restoration materials R specified therein.

4 sketches a tooth Z and a tooth model M. The stages of tooth restoration result from left to right. First, the intact tooth Z is shown on the left. It is believed that he is carious. Geometry data GD and (real) color data are taken from this tooth, with the (real) color data D of the carious part being interpolated from measured data of the surrounding tooth substance. Then part of the enamel or dentine is removed in a tooth area B to be simulated as part of the dental treatment. This tooth area B to be reproduced should then be closed with a restoration element E (here an inlay). It is advantageous if the data about the tooth area B to be simulated is also contained in the geometric data GD.

To produce the restoration element E, a tooth model M is first calculated from the geometry data GD and contains a predetermined distribution of a number of restoration materials R (middle image). The best tooth model M is selected according to the method 3 as result model EM. The restoration element E is now produced according to this result model EM (here an inlay). Of course, the entire result model M does not have to be produced, only the tooth area B to be reproduced. However, the method ensures that the color of the restoration element E will match the tooth Z very well.

The resulting tooth Z is shown on the right. The region in which the restoration element E is arranged is indicated in the image. In reality, this will no longer be recognizable due to the good color match.

In 5 the arrangement of a tooth volume V in a virtual material body K is shown. This can be used to create a tooth model M. Here, the model of a material body K with a predetermined distribution of restoration materials R (layers indicated by dot-dashed lines) is used and the tooth volume V is arranged therein. For the resulting tooth model M shown on the right, that part of the material body R in which the tooth volume V lies is then used. The tooth model M then also has a layered structure of restoration materials R, as indicated by dash-dotted lines.

Finally, it is noted that the use of the indefinite article, such as "a" or "an", does not rule out the possibility that the relevant characteristics can also be present more than once. So "a" can also be read as "at least one". The expression "a number" is also to be understood as "at least one". Terms such as "unit" or "device" do not exclude that the elements in question can consist of several cooperating components, which are not necessarily housed in a common housing, although the case of a comprehensive housing is preferred.

Reference List

1

contraption

2

Database

3

Data interface / data unit

4

modeling unit

5

simulation unit

6

comparison unit

7

selection unit

8th

output unit

10

dental device

11

projection device

12

image sensor

13

investigation unit

20

light source

21

projection unit

22

objective lens

AD

output data

B

tooth area

D

(real) color data

E

restoration element

EM

results model

G

denture

DG

geometry data

K

material body

M

tooth model

R

Restorative material / material

SD

simulated color data

V

tooth volume

WD

material data

Z

Tooth

Eg

tooth area

Claims (12)

Method for the automated selection of restoration materials (R) for a restoration element (E) for the restoration of a tooth (Z), the method comprising the steps: a) Provision of material data (WD) on optical, color-determining properties of a plurality of restoration materials (R), b) providing or recording geometry data (GD) on the 3D geometry of a tooth area (B) to be simulated and a plurality of color data (D) characterizing the tooth (Z), c) Creation of a virtual tooth model (M) of at least the tooth area (B) from the geometric data (GD), the tooth model (M) being constructed from a distribution of a number of the restoration materials (R) whose material data (WD) are in the database ( 2) are included, d) Simulation of color-characterizing simulated color data (SD) of the tooth model (M), based on the distribution of the restoration materials (R) in the tooth model (M), and the corresponding material data (WD) from the database (2), the simulated color data ( SD) are such that they can be compared with the color data (D), e) comparison of the simulated color data (SD) of the tooth model (M) with the color data (D), corresponding areas of the tooth (Z) and the tooth model (M) being compared in each case, f) At least in the case in which the comparison is outside a predetermined quality range: repeating steps c) to f) up to a predetermined termination criterion, with a new virtual tooth model (M) being created with each repetition, g) Selection of a result model (EM) from the number of created tooth models (M), h) Output of output data (AD) containing information which enable a restoration element (E) to be produced in accordance with the result model (EM). procedure after claim 1 , characterized in that the material data (WD) includes information on spectral scattering properties and/or spectral absorption properties and/or spectral refractive indices of the restoration materials (R), the material data (WD) preferably including data on the scattering coefficient and/or the phase function and/or the absorption coefficients and/or the refractive index of the corresponding material, preferably with the simulation of the simulated color data (SD) being carried out by means of calculations based on the optical scattering and absorption properties and the refractive index from the material data (WD) of the restoration materials (R). Method according to one of the preceding claims, characterized in that the color data (D) are determined by means of a spectrally resolved measurement of light which originates from the position of the tooth (Z), in particular based on remission and/or reflection, and/ or transmission and/or fluorescence, preferably using a defined illumination and/or detection geometry, with the simulation of the simulated color data (SD) preferably being carried out in such a way that during the simulation the same alignment of the tooth model (M) relative to the illumination and/or is simulated for detection as in the real recording of the tooth (Z), preferably with the color data (D) and preferably also the geometric data (GD) being obtained by means of structured illumination, preferably strip-shaped illumination, or also by means of homogeneous illumination. Method according to one of the preceding claims, characterized in that the restoration element (E) is produced automatically based on the output data (AD) or the output data (AD) comprise information by means of which automated production of the restoration element (E) is possible, with preference being given a layered or voxel-wise construction of the restoration element (E) takes place, in which a layer of a restoration material (R) or a mixture of restoration materials (R) in the form of a powder, a liquid or a paste is introduced into a construction area, solidified and then a number of others such layers is applied in this way to the last solidified layer, with the arrangement of the restoration materials (R) taking place according to the output data (AD), preferably with the structure taking place in the form of a 3D print or in the form of a solidification of pasty materials in the mouth . Method according to one of the preceding claims, characterized in that to create the virtual tooth model (M) additional data of a predetermined material body (K), in particular a blank, with a defined distribution of a number of restoration materials (R) are used on the geometric data (GD)-based tooth volume (V) is arranged in a virtual model of the material body (K) and the prevailing distribution of the number of restoration materials (R) of the material body (K) is used for the tooth model, preferably with a further tooth model (M ) the tooth volume (V) is arranged in a different position than before in the material body (K). Method according to one of the preceding claims, characterized in that to create the virtual tooth model (M) a plurality of restoration materials (R) are used, which essentially consist of the same base material, but include different admixtures of other materials which the restoration materials (R ) impart different optical, color-determining properties, preferably wherein - the material data (WD) of the plurality of restoration materials (R) with the different optical, color-determining properties are present in the database (2) or - the material data (WD) of a restoration material (R) are present , which corresponds to the base material and there is additional data on the other materials that indicate the extent to which adding these materials changes an optical, color-determining property of this restoration material (R). Method according to one of the preceding claims, characterized in that when providing or recording the plurality of color data (D), additional optical tooth data of the tooth are provided or recorded, in particular spectrally resolved information on refraction and/or scattering properties and/or absorption properties of the tooth, and the distribution of the number of restorative materials (R) in the tooth model (M) is based on the optical tooth data. Method according to one of the preceding claims, characterized in that the simulation of the simulated color data (SD) is carried out by means of calculations based on one or more of the following principles: - Calculation of a spectrally resolved light propagation in the tooth model (M) on the basis of Maxwell's equations or their Approximations, - Calculation of a spectrally resolved light propagation in the tooth model (M) based on a radiative transport equation, in particular by means of Monte Carlo simulations or analytical solutions, - Calculation of a spectrally resolved light propagation in the tooth model (M) based on an approximate solution of the radiative transport equation, - Calculation of a spectrally resolved light propagation in the tooth model (M) based on a generalized radiation transport equation, - use of an adaptive algorithm for simulation, which is based on the spectrally resolved light propagation for a large number of different dentures and/or tooth models (M) made of different materials (R), - use of an adaptive algorithm which is based on a large number of measurements of color-characterizing color data (D) of a large number of different dental prostheses and/or tooth models (M) made of different Materials (R) has been trained, - Use of a table pre-calculated on the basis of the radiation transport theory for a large number of tooth models (M). Method according to one of the preceding claims, characterized in that the output data (AD) contain one or more pieces of information selected from a group comprising information: - at what position and what orientation the restoration element (E) must be arranged in a material body (K). , - how the restoration element (E) has to be milled out of a material body (K), - for the structure of the material body (K), from which a restoration element (E) is to be milled out, - what distribution of restoration materials (R) where in the restoration element ( E) is available, - to print data for 3D printing of the restoration element (E), preferably which material is to be used in each volume element of the 3D print, in which case a further step of the method is in particular the printing of the restoration element (E). , - to a recipe for mixing different restoration materials (R), - to the result model (EM), in particular a virtual image of a final restoration element (E). Method according to one of the preceding claims, characterized in that a number of differences between the simulated color data (SD) and the color data (D) is calculated for the comparison and, if steps c) to f) are run through several times, preferably tooth models (M) so be designed to minimize this difference, with the result model (EM) preferably being that tooth model (M) in which the difference was the smallest. Device (1) for the automated selection of restoration materials (R) for a restoration element (E) for the restoration of a tooth (Z), in particular designed for carrying out a method according to one of the preceding claims, the device (1) comprising: - A database (2) comprising material data (WD) on optical, color-determining properties of a plurality of restoration materials (R), - a data unit (3) designed to provide or record geometry data (GD) for the 3D geometry of a tooth area (B) to be simulated and a plurality of color-characterizing color data (D) of the tooth (Z), - A modeling unit (4) designed to create a virtual tooth model (M) of at least the tooth area (B) from the geometric data (GD), the tooth model (M) being composed of a distribution of a number of restoration materials (R) whose material data ( WD) are included in the database (2), - a simulation unit (5) designed for simulating color-characterizing simulated color data (SD) of the tooth model (M), based on the distribution of the restoration materials (R) in the tooth model (M), and the corresponding material data (WD) from the database (2) , the simulated color data (SD) being such that they can be compared with the color data (D), - a comparison unit (6) designed to compare the simulated color data (SD) of the tooth model (M) with the color data (D), corresponding areas of the tooth (Z) and the tooth model (M) being compared in each case, - a selection unit (7) designed to select a result model (EM) from the number of created tooth models (M), - an output unit (8) designed to output output data (AD) containing information which enable a restoration element (E) to be produced in accordance with the result model (EM). Dental device (10) comprising a device (1). claim 11 and preferably additionally - a projection device (11) designed to radiate light onto a tooth (Z), - an image sensor (12), in particular a camera, designed to capture light which originates from the position of the tooth (Z), and - a determination unit (13) designed to determine a large number of color-characterizing color data (D) of different areas of the tooth (Z) from the light beams detected by the image sensor (11), and preferably also geometry data (GD) for the 3D geometry of the tooth (Z ).

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