Arrangement for the guided grinding of a tooth in five degrees of freedom

Abstract

Arrangement for the guided grinding of a tooth (1) having a chewing surface (11) with a relief (12), in five degrees of freedom, comprising a guide body (2) and a grinding body (3), characterized in that - the guide body (2) consists of an upper part (21), a middle part (22) and a lower part (23), wherein the upper part (21), the middle part (22) and the lower part (23) are designed as a cylindrical solid body, the diameter of the upper part (21) is smaller than the diameter of the middle part (22), the diameter of the middle part (22) is smaller than the diameter of the lower part (23) and the diameter of the lower part (23) is smaller than the circumference of the tooth (1) to be ground, wherein the transition from the upper part (21) to the middle part (22) is designed as a circumferential edge (4), the transition from the middle part (22) to the lower part (23) is continuous without an edge and the surface of the lower part (23) facing away from the middle part (22) has a relief (24) which in its shape corresponds to the relief (12) of the chewing surface (11) of the Tooth (1) is,and this guide body (2) can be reversibly applied to the tooth (1) via a composite material between the relief (24) and the relief (12), and - the grinding body (3) consists of a smooth cylindrical upper part (31), a cylindrical middle part (32) with a guide element (5) running continuously around its surface and a cylindrical lower part (33), wherein the surface of the lower part (33) facing away from the middle part (32) is hemispherical in shape and carries grinding particles and the guide element (5) of the grinding body (3) can be placed correspondingly on the side of the edge (4) of the guide body (2) facing the upper part (21) and can be guided by this in a circumferential manner around the middle part (22).

Description

[0001] The invention relates to an arrangement for the guided grinding of a tooth in five degrees of freedom, in particular for contour-accurate grinding even in the case of teeth that are difficult to see and for avoiding accidental grinding of the adjacent tooth next to the tooth to be treated.

[0002] The production of dental restorations and reconstructions, such as fillings, inlays, crowns, or bridges, places high demands on the skills of dentists and dental technicians. The manufacturing process requires considerable time both in the treatment room and in the dental laboratory, making it costly. The quality of the treatment outcome also varies depending on the skill of the treating dentist and, if applicable, the dental technician. Due to these influencing factors, a standardized and consistently high quality of treatment outcome has not yet been possible to a satisfactory extent.

[0003] While intraoral scanners and digital manufacturing processes (CAD / CAM) have made results outside the dental treatment room more predictable, the preparation process—the grinding of teeth in the mouth by the dentist until they are in a suitable shape suitable for dental restorations or reconstructions—remains as complex, analog, and non-standardizable as ever. The most influential factor is still the skill of the individual dentist under varying conditions during preparation.

[0004] The preparation, or grinding, of a tooth is a dentist's high art, as it requires preserving the tooth substance, respecting its anatomy, and creating a smooth shape suitable for replacement materials. The greatest challenges here are the sometimes poor visibility (visibility!), the potentially limited accessibility, and the difficulty of defining a suitable preparation margin under adverse conditions. This appropriate preparation margin is the boundary between the ground and unground portions of the tooth. It should be even and smooth, ensure a sufficient layer thickness, and be positioned in exactly the right place. This guarantees a tight seal with the workpiece to be finished. However, it is sometimes impossible to maintain visual control during grinding. Therefore, it is not uncommon for parts of the preparation margin to be ground without vision, "by feel" by the practitioner. This is a process whose success depends solely on the skill and experience of the practitioner. An unsatisfactory situation.

[0005] DE 199 02 273 A1 discloses a device for determining the placement of dental implants in the jawbone by means of a computer-assisted navigation system, in which the position of the implant drill is imaged three-dimensionally in X-ray images together with an adjacent bone, and in which a dynamic reference frame is attached to an individually bent wire fixed to the remaining teeth with plastic via a sleeve connection that can be screwed during the operation.

[0006] The disadvantage of this technical solution is that it is not suitable for guided grinding of a tooth in five degrees of freedom.

[0007] DE 199 52 962 A1 relates to a method for creating a drilling aid for a dental implant. The method comprises the following steps: first, taking an x-ray of the jaw and creating a corresponding measurement data set. Next, a three-dimensional optical measurement of the visible surface of the jaw and teeth is performed, and a corresponding measurement data set is generated. The measurement data sets from the x-ray image and the measurement data sets from the three-dimensional optical image are correlated. Using the information then available, the type and position of the implant relative to the neighboring teeth is planned, and a drilling template is generated. This drilling template is attached to the neighboring teeth, thus enabling the precise drilling of the implant guide hole.

[0008] The disadvantage of this technical solution is that it is not suitable for guided grinding of a tooth in five degrees of freedom.

[0009] DE 197 25 197 A1 discloses a method and device for locating dental implants. They process anatomical data relating to the jawbone structure of the patient in question, acquired by measurement. Based on the stored data, cross-sectional image information is generated, which is used to define the implantation site. Using an assigned reference coordinate system, the actual bone geometries, the measurement information, the design of a jaw plaster model, and the geometry of an auxiliary surgical template can be related to one another with such precision that highly accurate placement of a hole in the jawbone to accommodate the dental implant is supported.The transmission of the respective coordinate information to the auxiliary devices and processing equipment used is supported by a mechanical transmission element, which can, for example, have an arc-shaped design and holds an adapter that can be inserted into the patient's mouth area.

[0010] The disadvantage of this technical solution is that it is not suitable for guided grinding of a tooth in five degrees of freedom.

[0011] WO2014 / 154584 A1 discloses a method for planning a root canal treatment of a patient, wherein a cavity on a tooth to be treated has already been prepared, wherein a surface of the cavity is measured by means of an optical three-dimensional measuring method and three-dimensional measurement data of the cavity are generated in the process, wherein a 3D model of a guide template is planned on the basis of the generated three-dimensional measurement data, the dimensions of which are designed as a counterpart to the prepared cavity, wherein a position and an orientation of at least one root canal are determined on the basis of three-dimensional volume data of the tooth to be treated, wherein at least one guide opening for a tool for exposing the root canal is planned, wherein the guide opening is arranged within the guide template such that the guide opening points to an entry point of the root canal and in an entry direction of the root canal.

[0012] The disadvantage of this technical solution is that it is not suitable for guided grinding of a tooth in five degrees of freedom.

[0013] WO 2014 / 187715 A1 discloses a method for producing a patient-specific replacement bracket comprising the following steps: a) Providing a 3D representation of a patient’s upper or lower jaw in the target setup with a reference plane in a computer, b) Receiving a request to produce a replacement bracket for a tooth of the upper or lower jaw, c) Defining a section of the 3D representation of the upper or lower jaw that contains at least a portion of the tooth for which the replacement bracket is to be manufactured, d) generating a marker (5MS) for the slot plane (3SE) in the section using the reference plane, e) Creating a physical model of the section with the marking (5MS), f) Providing a bracket element containing the slot (3S), e.g. a bracket body or a standard bracket, g) Align the bracket element to the slot plane (3SE) and h) Assignment of an individualized pad to the bracket element, whereby the replacement bracket is produced.

[0014] The disadvantage of this technical solution is that it is not suitable for guided grinding of a tooth in five degrees of freedom.

[0015] US 6015289 A teaches a system and method for automatically designing and manufacturing an orthodontic appliance from a patient's digital lower jaw and tooth shape data. It provides for preferably scanning a model of the patient's mouth to generate two- or three-dimensional images and digitizing contours and selected points. A computer is programmed to construct dental arches and calculate the final positions of the teeth and then designs an appliance, preferably including archwires and brackets, to move the teeth into the calculated positions. The lower teeth are positioned at their roots on an arch defined by the mandibular bone, and the arch is modified to best fit the tooth apices in a gentle curve. Upper archforms are constructed for the upper teeth.Machine code is then generated, and appliances are automatically manufactured to straighten the patient's teeth. Custom placement devices are also automatically designed and manufactured and delivered with the customized appliance to position the appliance on the patient's teeth.

[0016] The disadvantage of this technical solution is that it is not suitable for guided grinding of a tooth in five degrees of freedom.

[0017] WO 2001 / 85047 A2 discloses a method and apparatus for generating an orthodontic template that assists in the placement of an orthodontic appliance. The method includes processing that begins with obtaining a digital model of a patient's orthodontic structure. Processing continues by selecting one of a plurality of orthodontic appliances for the orthodontic structure to fabricate a selected orthodontic appliance. A digital model of the placement of the selected appliance is created, then a digital image of a tooth mounting fixture is retrieved.An orthodontic template for holding a physical embodiment of the retaining device is created based on the digital image of the retaining device, the digital model of the placement, and at least a portion of the digital model of the orthodontic structure.

[0018] The disadvantage of this technical solution is that it is not suitable for guided grinding of a tooth in five degrees of freedom.

[0019] It is known from DE 36 35 122 A1 that in dental surgery, if a tooth is to be provided with a crown, it must be tapered by drilling, milling and grinding, and that it has been found that in order to successfully fix a crown, the cone must be prepared much more precisely than is possible with the equipment currently available.

[0020] The technical solution according to the teaching of DE 36 35 122 A1 allows the initial position of a drill's axis to be set in relation to a selected axis using electronic "spirit levels" in a housing. A greater deviation from this axis than a predetermined amount is indicated by so-called LEDs (light-emitting diodes) A, A', B, B', and others, which can be seen regardless of the position of the hand tool 14 holding the drill 10. By means of a code, these LEDs indicate how the dentist must move the drill to return to the correct axis.

[0021] The disadvantage of this technical solution is that it is not suitable for guided grinding of a tooth in five degrees of freedom.

[0022] EP 3 100 699 B1 discloses a method for producing a surgical guide template and a crown for a dental implant, the method comprising: • a first process of bonding a tray having a plurality of reference marks affixed to a side surface thereof and an impression material injected into an inner surface thereof to an inside of a patient's mouth to take an impression having a groove conforming to a second image corresponding to a tooth implantation portion; • a second process for obtaining an integrated scanned image and for obtaining a CT image by computed tomography of the upper and lower jaws; • a third process of obtaining a three-dimensional occlusion guidance image by superimposing the obtained integrated scanned image on the acquired CT image using the reference marks as references and merging the images by a main merging process into a difference map from which an image matching degree between the images is output, and • a fourth process of adjusting a height of a crown based on the three-dimensional occlusion guide image, and manufacturing a surgical guide template including a fixation groove conforming to an inner shape of the patient's mouth and a guide hole formed along an implementation position of a fixture corresponding to the adjusted crown, wherein • the second process includes obtaining a primary scanned image by scanning the tray in which an occlusal height is adjusted by stacking an occlusal base on an outer surface thereof and adjusting a thickness thereof, and obtaining a secondary scanned image by orally scanning a closed state of the upper and lower jaws.

[0023] The disadvantage of this technical solution is that it is not suitable for guided grinding of a tooth in five degrees of freedom.

[0024] As the closest prior art, DE 39 10 235 A1 discloses the following: In a device for correctly orientating grinding of tooth surfaces, comprising a grinding device having a shaft with a rotating grinding body, a lever mechanism on which the grinding device is arranged, and fastening means for attaching the lever mechanism to a tooth of a denture, the fastening means comprises a body whose outer dimensions in at least one spatial direction are significantly smaller than the corresponding outer dimensions of the tooth, and the body is attached to at least one side wall and / or the chewing surface of the tooth. This creates a device that also enables extensive grinding of the tooth to which the device is attached in a simple and cost-effective manner.

[0025] The disadvantage of this technical solution is that it is not suitable for the guided grinding of a tooth in five degrees of freedom, so that it must be concluded that all previous approaches to date do not provide any aid that guides the grinding in the necessary five degrees of freedom. In summary, for the grinding of teeth for crowns, the following should be pointed out, which is already known in the relevant professional circles: In dental implantology, CAD / CAM templates are used for the placement of implants. These guide instruments for drilling holes in the bone. They specify the direction and depth. However, these templates only allow linear drilling, meaning they only guide in one degree of freedom.

[0026] Some technical solutions apply the approach of implant drilling guides to tooth grinding by providing tooth-supported templates with drill holes that the dentist can use as depth markers. However, the templates must be removed before the actual preparation and do not support the actual grinding process. The problems of restricted visibility, limited accessibility, and a lack of control over the grinding result remain, which, in turn, depends entirely on the skill of the individual dentist.

[0027] However, all of these technical solutions are not optimal, as these systems ultimately only allow support in one degree of freedom. And they do not provide guidance when grinding teeth, as they cannot remain in the mouth for this purpose.

[0028] One historically postulated approach is the use of parallelization rods, but these were not universally applicable due to limited space and are therefore no longer used in practice today. Furthermore, by their very nature, they were limited to two, at most three, degrees of freedom.

[0029] Research and development is currently underway to develop robots specialized for this task. However, these are not yet market-ready, and their initial use will be very costly, so not every dental practice will have such a robot in the near future.

[0030] The object of the present invention is to provide an arrangement for the guided grinding of a tooth in five degrees of freedom, which avoids the disadvantages of the prior art, in particular enables contour-accurate grinding even in the case of teeth that are difficult to see and reach, and avoids accidental grinding of the adjacent tooth next to the tooth to be treated, so that there is a high level of certainty regarding the predictability of the treatment success and a high quality of treatment is ensured regardless of the practitioner.

[0031] According to the invention, this object is achieved by the features of the first claim. Further advantageous embodiments of the invention are specified in the subordinate claims.

[0032] The provided arrangement for the guided grinding of a tooth having a chewing surface with a relief in five degrees of freedom comprises a guide body and a grinding body.

[0033] The guide body consists of an upper part, a middle part, and a lower part. These three parts are designed as cylindrical solid bodies. The diameter of the upper part is smaller than the diameter of the middle part, the diameter of the middle part is smaller than the diameter of the lower part, and the diameter of the lower part is smaller than the circumference of the tooth to be ground. The transition from the middle part to the lower part is continuous without an edge, and the lower part is adapted to the respective tooth geometry. Thus, it is also within the scope of the invention that the idealized shape of the cylindrical solid body can correspond in its cross-section to the cross-section of the respective tooth shape.

[0034] It is important that the transition from the upper part to the middle part of the guide body is designed as a circumferential edge, the surface of the lower part facing away from the middle part has a relief which corresponds in shape to the relief of the chewing surface of the tooth, and this guide body can be reversibly applied to the tooth via a composite material (according to the state of the art) between the relief of the lower part and the relief of the chewing surface of the tooth.

[0035] The grinding body of the provided arrangement consists of a smooth cylindrical upper part, a cylindrical middle part with a guide element running continuously around its surface and a cylindrical lower part.

[0036] It is essential that the grinding body carries grinding particles on the surface of its lower part and that the guide element can be placed correspondingly on the side of the edge of the guide body facing the upper part and can be guided by this around the middle part.

[0037] Advantageously, the grinding body has a hemispherical shape on its surface of the lower part facing away from the central part, which carries grinding particles.

[0038] Advantageously, the guide body with its lower part having the relief is produced by 3D printing according to the state of the art on the basis of standardized basic data for its upper part, its middle part and its lower part as well as on the basis of data of the relief of the chewing surface of the tooth determined by scanning according to the state of the art.

[0039] The cylindrical upper part, the cylindrical middle part with a guide element running continuously around its surface and the cylindrical lower part of the grinding wheel are made of a metal, e.g. steel, stainless steel or another metal or metal alloy.

[0040] The grinding particles of the grinding wheel consist of diamond chips, which corresponds to the state of the art.

[0041] In a further embodiment of the arrangement, the guide body is advantageously connected on its upper side via a connecting element to a support element for a neighboring tooth of the tooth. The support element has a relief on its underside opposite the support element, the shape of which corresponds to the relief of the chewing surface of the neighboring tooth.

[0042] The guide body of this embodiment is manufactured with the connecting element and the supporting element by 3D printing according to the state of the art using standardized basic data and data of the relief of the occlusal surface of the adjacent tooth of the tooth to be treated, which were determined by scanning according to the state of the art.

[0043] The basis for the implementation of this technical solution is the use of a preferably CAD / CAM-manufactured arrangement with a guidance function in all five degrees of freedom in order to enable grinding of a tooth in five degrees of freedom using standardized grinding tools.

[0044] The starting point is a software component for the individual planning of the geometry of the preparation required for the restoration or reconstruction, the dependent design of the grinding tool guide and the selection of the required standardized grinding tools.

[0045] 3D data of the oral situation, especially of the teeth and bite, are read into the software and based on this data the operator determines the geometry required for the restoration or reconstruction, designs the guide bodies and selects the corresponding standardized grinding bodies.

[0046] The custom-made guide bodies are manufactured using industry-standard CAM machines (milling or 3D printing). The guide bodies themselves then have a customized shape adapted to the respective geometry. The guide bodies store information about the geometry of the preparation depth, shape, inclination, and, most importantly, the vertical and horizontal contours of the preparation margin.

[0047] The guide elements thus have plane and depth guidance elements in all five degrees of freedom and work with standardized grinding tools. They allow a dentist, regardless of their own skill level and with limited visual control, to prepare a tooth in the shortest possible time using preselected grinding tools of the appropriate length.

[0048] This also makes it easy to prepare multiple teeth in the same insertion direction. However, more than one guide may be required.

[0049] This is also the case when the occlusal anatomy of a tooth does not allow for precise positioning and permanent anchoring of the guide body on the occlusal surface. In this case, an additional guide body would be required to prepare the tooth region in which the connector is located. It therefore makes sense to individually and clearly mark the occlusal surface of a tooth to be prepared before collecting the 3D situation data (for example, by grinding in a cross or plus sign).

[0050] The geometry of the guide body is a central element in the provided arrangement.

[0051] The grinding result planned with the software is encoded in the geometry of the guide body.

[0052] Because the underside of the guide body is congruent with the occlusal surface of the tooth to be ground, the guide body can sit gap-free and in a precisely defined position. This ensures the orientation of the guide body to the tooth.

[0053] The upper surface of the guide body is largely smooth (but not flat) and has a clean edge toward the lateral surface. This encodes the course of the subsequent preparation margin in the vertical plane (i.e., up and down; Z-axis).

[0054] The circumferential surface encodes the planned preparation geometry in terms of shape, preparation depth (removal), and inclination angle, as well as the horizontal contour of the preparation margin. The grinding tools are guided tangentially along it during grinding. It represents the linear extension of the planned grinding shape toward the occlusal surface.

[0055] The horizontal cross-section of the lateral surface is an individual anatomical shape.

[0056] The cross-section thus encodes the grinding result in two degrees of freedom. The circumferential surface is designed with varying conicity, thus encoding two additional degrees of freedom. The circumferential surface also varies in height; the grinding wheels are guided by a depth stop at their upper edge, thus encoding the fifth degree of freedom.

[0057] In this way, the guide body enables the translation of the grinding result planned in the software onto the tooth.

[0058] The use of standardized grinding tools in the provided arrangement is advantageous and necessary because it allows their standardized geometry to be taken into account and selected in the CAD process of the software and adapted to the respective guide body for the desired treatment result.

[0059] The grinding bodies are also designed so that they can be used with commercially available dental transmission instruments (contra-angles and turbines).

[0060] The grinding wheels are divided into 3 zones: 1. upper section = shaft - this serves to fix the device in the angle piece and can be made of highly polished steel, for example (it can also have an optical coding, visible to the practitioner for better recognition); 2. middle area = guide area - this can also be made of highly polished steel, for example, and here you will find the geometries for preparation that are matched to the guide geometries of the guide bodies; 3. lower area = working end, this can be diamond-coated, for example, and is used to remove tooth substance.

[0061] Different grinding wheels differ in their diameter and length of the diamond-coated working end and in the length of the guide area.

[0062] When using the provided arrangement in practice beyond the preparation margin and the insertion direction, it is within the scope of the technical solution that occlusal shaping (grinding of the chewing surface) can also be carried out during preparation using the same technique.

[0063] The same guiding body technique can be used for all dental restorations and reconstructions, for example for the preparation of the access cavity in endodontics (root canal treatment).

[0064] It can be used to create a wide variety of cavities and preparation geometries.

[0065] It can be used to produce temporary restorations before grinding, in parallel with the production of the guide bodies.

[0066] The software can be extended to include elements during the design process that serve to protect and contain soft tissues, namely the tongue and cheek, during grinding.

[0067] The casing of the guide body can be extended to include guide elements for the grinding wheels that go beyond a purely tangential guide.

[0068] The guide geometry of the guide body and the grinding wheel can then be designed in such a way that the operator cannot select the wrong grinding wheel. Due to the tangential approach of the grinding wheel to the casing, complex rotationally symmetric geometries can be used in a highly encrypting manner.

[0069] Many of the CAM materials already on the market can be used as manufacturing materials.

[0070] A special material may be useful or even necessary for the production of the guide bodies.

[0071] Numerous additional functions can be integrated into the software, such as matching 2D and 3D X-ray images, photos, and matching planned restoration geometries.

[0072] The software can create the planned final situation with the finished restoration or reconstruction in the mouth in advance as 3D data, which can then be exported and used in other software solutions (common dental CAD programs such as Exocad). This allows the final restoration or reconstruction to be completed before the teeth are prepared, and then inserted in the same session following preparation with the guides. This would enable very rapid treatment with a predictably good result in just one treatment session, since the final restoration is already completed by the time of preparation.

[0073] The technical solution also includes the creation of a splint (ceramic protection, bruxism, etc.) using the provided arrangement.

[0074] The guide body and software can be used to create the final restoration before the teeth are ground.

[0075] The individual advantages of the technical solution provided are listed below: The advantage of this technical solution is that by using this arrangement of guide body and grinding wheel, the grinding process becomes simpler, safer, faster, more cost-effective, and predictable. Quality is standardized and potentially significantly increased while costs are reduced.

[0076] The treatment time in the mouth is also reduced, which benefits the patient’s well-being.

[0077] The creation of 3D data and the production of guide bodies can be carried out by less qualified personnel and, in the long term, can certainly be outsourced to AI systems.

[0078] The necessary materials for guide bodies and grinding wheels are inexpensive and readily available.

[0079] The necessary systems for collecting reliable 3D data are already available through modern intraoral scanners, although they are not yet ubiquitous.

[0080] The qualification requirements for the performing dentist are lowered, which in exceptional cases even makes delegation to non-dentists or AI systems conceivable. Consider drilling rigs, naval operations, research stations, or manned space flight – situations where visiting a dentist for an extended period of time is impossible.

[0081] The aspect of clinical applicability is particularly important in the technical solution provided.

[0082] The approach of guidance system-assisted preparation using the provided setup can be implemented in any modern dental practice, as the setup is very easy to use and involves low acquisition costs. In addition to the setup, the following additional elements are required in the practice: 1. Accurate 3D data of the teeth and oral situation, as created by current dental 3D intraoral scanners. 2. A suitable computer to use the software. 3. The usual furnishings of a dental practice. 4. CAM equipment, e.g., in the form of 3D printers or milling machines. Alternatively, production can be outsourced to external milling centers or 3D printing laboratories.

[0083] Using impressions and subsequent digitization of the models, or preferably using 3D scans of the teeth, a suitable preparation geometry is defined in the software and a corresponding guide body for the standardized grinding tools is then created either manually or with the help of AI. This is then printed or milled, preferably using CAM technology.

[0084] During the preparation session, the guide body is dentally anchored (glued to the occlusal surface or attached to the adjacent teeth). The standardized grinding tools are used in standard dental contra-angle handpieces (or turbines). During preparation, the operator uses the standardized grinding tools to transfer the geometry defined in the guide body in five degrees of freedom to the tooth.

[0085] To do this, the "depth stop," in the form of the grinding wheel's circumferential guide element, is placed against the edge of the guide wheel and then slowly grinds the tooth with rotating movements while cooling with water. The end point is reached when the top and outer surface of the guide wheel are in full contact with the "depth stop" and the "tangential surface" of the grinding wheel.

[0086] Different geometries in the working ends of the grinding wheels can be used to create different preparation limits.

[0087] In addition, variations in the thickness and diamond coating of the grinding wheels can be used to prepare a tooth as gently as possible in several grinding steps.

[0088] With the varying length of the standardized grinding tools preselected in the software, the accessibility of distal areas in the mouth can be taken into account and improved, even in patients with partially severely restricted mouth opening.

[0089] For clinical success, the guide body must fit precisely onto the chewing surface of the tooth being prepared and be anchored securely in position. This can be achieved by directly bonding it to the chewing surface of the tooth being prepared, if necessary after preparing the chewing surface with precise, cross-shaped grinding.

[0090] Alternatively, the guide body can also be designed with additional anchoring elements on the adjacent teeth. In this case, it is obviously necessary to create several guide bodies with differently positioned connectors to grind a tooth, since a connecting element would naturally interfere with the circular grinding of the tooth at one point.

[0091] In addition, in the area of ​​the small anterior teeth and premolars, it may be necessary to work with multiple guide bodies, since the guide geometries, such as the conicity of the shell, require space and would overlap if the radii were too small.

[0092] A further advantage of the provided arrangement is the ability to uniformly grind multiple teeth using multiple connected guide bodies. This allows our system to be used, for example, in veneer solutions, telescopic solutions, and bridges with customized insertion directions.

[0093] Approved dental materials that allow cost-effective and highly accurate implementation are used to create the guide bodies, such as highly ceramic-filled dental composite materials or plastics.

[0094] The CAD software is designed for use on standard workstations. If necessary, the functionality can also be integrated into existing laboratory software.

[0095] The 3D situation in the patient’s mouth is imported into the software from an external source.

[0096] The software displays this imported data and allows the user to orientate and navigate within it.

[0097] The user marks the desired teeth.

[0098] The user selects the desired restoration material, for which the necessary removal thicknesses, layer thicknesses and conicities for optimal removal forces are stored in the software.

[0099] The user defines the central axis of the preparation of each tooth.

[0100] The user marks the desired preparation margin. In proximal areas (between the teeth), where the preparation margin is not visible, it is extrapolated. The same procedure can be used for a slightly subgingival (below the gum) placement.

[0101] The user marks opportune support areas.

[0102] The software generates a 3D model of the guide body, adapted to the user input and the underlying 3D data.

[0103] In the process, the appropriate grinding wheel is selected and displayed; optionally, the guide wheel is labeled accordingly during printing.

[0104] Based on the desired material, the CAD process automatically calculates the ideal minimum removal rate. The user can intervene, as a larger or smaller removal rate may be appropriate from a prosthetic perspective, depending on how far the planned geometry of the restoration or reconstruction differs from the geometry of the existing tooth.

[0105] The 3D data of the guide body generated by the software is used to manufacture it in conventional dental CAM machines (printers or milling machines).

[0106] The invention is explained in more detail below with reference to the exemplary embodiments and the figures, without being limited to these.

[0107] Show this: Fig. 1: a highly simplified schematic representation of a tooth in oblique top view, Fig. 2: a schematic 3D representation of a first embodiment of the guide body according to the invention on a tooth to be ground in an oblique top view, Fig. 3: a schematic 3D representation of the first embodiment of the guide body according to Fig. 2 on a tooth to be ground in side view, Fig. 4: a first schematic 3D representation of the first embodiment of the guide body according to Fig. 2 on a tooth to be ground with standardized grinding wheels attached to the guide body as a whole during grinding in side view, Fig. 5a: a second schematic 3D representation of the first embodiment of the guide body according to Fig. 2 on a tooth to be ground with standardized grinding wheels attached to the guide body as a whole in accordance with Fig. 4 during grinding in side view, Fig. 5b: a third schematic 3D representation of the first embodiment of the guide body according to Fig. 2 on a tooth to be ground with standardized grinding wheels attached to the guide body as a whole in accordance with Fig. 4 during grinding in side view, Fig. 6: a schematic 3D representation of a second embodiment of the guide body according to the invention on a tooth to be ground in side view and Fig. 7: a schematic 3D representation of a second embodiment of the guide body according to the invention on a tooth to be ground according to Fig. 6 in top view

[0108] The Fig. The embodiment of the arrangement shown in Figures 2 to 5 for the guided grinding of a tooth (1) [which has a chewing surface (11) with a relief (12)] in five degrees of freedom comprises a guide body (2) and a grinding body (3).

[0109] The guide body (2) consists of an upper part (21), a middle part (22) and a lower part (23), wherein the upper part (21), the middle part (22) and the lower part (23) are designed as a cylindrical solid body, the diameter of the upper part (21) is smaller than the diameter of the middle part (22), the diameter of the middle part (22) is smaller than the diameter of the lower part (23) and the diameter of the lower part (23) is smaller than the circumference of the tooth (1) to be ground, wherein the transition from the middle part (22) to the lower part (23) is continuous without an edge.

[0110] It is essential that the transition from the upper part (21) to the middle part (22) is designed as a circumferential edge (4), the surface of the lower part (23) facing away from the middle part (22) has a relief (24) which corresponds in shape to the relief (12) of the chewing surface of the tooth (1), and this guide body (2) can be reversibly applied to the tooth (1) via a composite material between the relief (24) and the relief (12), wherein the grinding body (3) consists of a smooth cylindrical upper part (31), a cylindrical middle part (32) with a guide element (5) running continuously around its surface and a cylindrical lower part (33) which carries grinding particles on its surface, and the surface of the lower part (33) facing away from the middle part (32) is hemispherical in shape and carries grinding particles and the guide element (5) of the grinding body (3) is directed correspondingly to the,the side of the edge (4) of the guide body (2) facing the upper part (21) and can be guided by this around the middle part (22).

[0111] The guide body (2) with its lower part (23) with the relief (24) is produced by 3D printing according to the state of the art using standardized basic data for the upper part (21), the middle part (22) and the lower part (23) as well as using data of the relief (12) of the chewing surface of the tooth (1) determined by scanning according to the state of the art.

[0112] The cylindrical upper part (31) or the cylindrical middle part (32) with a guide element (5) running continuously around its surface and the cylindrical lower part (33) of the grinding body (3) consist of a metal, for example steel, stainless steel or another metal or metal alloy.

[0113] The grinding particles of the grinding body (3) consist of diamond chips.

[0114] Advantageously, the guide body (2) is in a further embodiment of the arrangement according to Fig. 6 and Fig. 7 is connected at its upper side (21) via a connecting element (6) to a support element (7) for a neighboring tooth of the tooth (1). The support element (7) has a relief on its underside (71) opposite the support element (7), the shape of which corresponds to the relief (12) of the chewing surface of the neighboring tooth.

[0115] The guide body (2) of this embodiment with the connecting element (6) and the supporting element (7) is produced by 3D printing according to the state of the art on the basis of standardized basic data and on the basis of data of the relief of the chewing surface of the adjacent tooth of the tooth (1) determined by scanning according to the state of the art.

[0116] The advantage of all embodiments of the provided arrangement for the guided grinding of a tooth in five degrees of freedom is that contour-accurate grinding is possible even with teeth that are difficult to see and reach, and that accidental grinding of the adjacent tooth next to the tooth to be treated is avoided.

[0117] In addition, this provides a high level of certainty regarding the predictability of treatment success and ensures a high quality of treatment regardless of the practitioner.

[0118] All features presented in the description, the exemplary embodiments and the following claims can be essential to the invention both individually and in any combination with one another. Reference symbol 1 tooth 11 chewing surface 12 Relief 2 guide bodies 21 Top 22 Middle section 23 Lower part 24 Relief 3 grinding wheels 31 top 32 Middle section 33 Lower part 4 edge 5 circumferential guide element 6 Connecting element 7 Support element 71 Underside of the support element QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 199 02 273 A1

[0005] DE 199 52 962 A1

[0007] DE 197 25 197 A1

[0009] WO 2014 / 154584 A1

[0011] WO 2014 / 187715 A1

[0013] US 6015289 A

[0015] WO 2001 / 85047 A2

[0017] DE 36 35 122 A1 [0019, 0020] EP 3 100 699 B1

[0022] DE 39 10 235 A1

[0024]

Claims

[1] Arrangement for the guided grinding of a tooth (1) having a chewing surface (11) with a relief (12) in five degrees of freedom, comprising a guide body (2) and a grinding body (3), characterized by , that - the guide body (2) consists of an upper part (21), a middle part (22) and a lower part (23), wherein the upper part (21), the middle part (22) and the lower part (23) are designed as a cylindrical solid body, the diameter of the upper part (21) is smaller than the diameter of the middle part (22), the diameter of the middle part (22) is smaller than the diameter of the lower part (23) and the diameter of the lower part (23) is smaller than the circumference of the tooth (1) to be ground, wherein the transition from the upper part (21) to the middle part (22) is designed as a circumferential edge (4), the transition from the middle part (22) to the lower part (23) is continuous without an edge and the surface of the lower part (23) facing away from the middle part (22) has a relief (24) which in its shape corresponds to the relief (12) of the chewing surface (11) of the Tooth (1) is,and this guide body (2) can be reversibly applied to the tooth (1) via a composite material between the relief (24) and the relief (12), and - the grinding body (3) consists of a smooth cylindrical upper part (31), a cylindrical middle part (32) with a guide element (5) running continuously around its surface and a cylindrical lower part (33), wherein the surface of the lower part (33) facing away from the middle part (32) is hemispherical in shape and carries grinding particles and the guide element (5) of the grinding body (3) can be placed correspondingly on the side of the edge (4) of the guide body (2) facing the upper part (21) and can be guided by this in a circumferential manner around the middle part (22). [2] Arrangement according to claim 1, characterized bythat the guide body (2) is produced by 3D printing on the basis of standardized basic data for the upper part (21), the middle part (22) and the lower part (23) and the relief (24) of the lower part (23) is produced on the basis of data of the relief (12) of the chewing surface of the tooth (1) determined by scanning. [3] Arrangement according to claim 1, characterized by that the cylindrical upper part (31), the cylindrical middle part (32) with the guide element (5) running continuously around its surface and the cylindrical lower part (33) of the grinding body (3) are made of steel or another metal or a metal alloy. [4] Arrangement according to claim 1, 2 or 3, characterized by that the grinding wheel (3) can be standardized and replaced. [5] Arrangement according to claim 1, 2, 3 or 4, characterized by that the grinding particles of the grinding body (3) are diamond chips. [6] Arrangement according to one or more of claims 1 to 5, characterized bythat the guide body (2) is connected on its upper side (21) via a connecting element (6) to a support element (7) for a neighboring tooth of the tooth (1) and the support element (7) has a relief on its underside (71) opposite the support element (7), which corresponds in shape to the relief (12) of the chewing surface of the neighboring tooth. [7] Arrangement according to claim 6, characterized by that the guide body (2) with the connecting element (6) and the support element (7) is produced by 3D printing on the basis of standardized basic data and on the basis of data determined by scanning the relief of the chewing surface of the adjacent tooth of the tooth (1). [8] Arrangement according to one or more of claims 1 to 7, characterized by , that • the circumferential surface of the guide body (2) determines the planned preparation geometry in terms of shape, preparation depth and angle of inclination as well as the horizontal course of the preparation border, in which the grinding body (3) is guided tangentially to it during grinding, and • the horizontal cross-section of the lateral surface of the guide body (2) can be designed in its individual anatomical shape according to the tooth (1), so that the cross-section determines the grinding result in two degrees of freedom, • the circumferential surface of the guide body (2) can be designed to vary its conicity and thus defines two additional degrees of freedom and • the circumferential surface of the guide body (2) is also variable in height and the grinding body (3) with its circumferential guide element (5) can be guided on the edge (4) of the guide body (2) as a depth stop and thus defines the fifth degree of freedom, wherein the surface of the guide body (2) is the linear extension of the planned grinding shape in the direction of the chewing surface (11) of the tooth (1).

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