Method for producing a dental prosthesis

Abstract

In a method for producing a dental prosthesis (2) which, for removable fastening to a number of teeth (6) crowned in each case by a patrix element (14) in the mouth of a patient, is provided with a number of matrix elements (18) corresponding in each case to one of the patrix elements (14), the aim is to enable a particularly good precision fit of the dental prosthesis (2) by processes that are kept as simple as possible. To this end, according to the invention, multi-part matrix elements (18) are used which each comprise an inner cap (32), to be plugged onto the associated patrix element (14), and an outer cap (34), mounted on the dental prosthesis (2), wherein, in the space between inner cap (32) and outer cap (34), said caps are connected to each other by an intermediate body (36) made of thermoplastic material, wherein, in order to precisely align the inner cap (32) relative to the outer cap (34) of the respective matrix element (18), the intermediate body (36) is heated to a temperature above its softening temperature and is thus made deformable, and then, by exploiting the deformability of the intermediate body (36), and taking consideration of intraoral data reflecting the actual dentition situation in the oral cavity of the patient, the inner cap (32) is aligned relative to the outer cap (34) to give an optimized precision fit, before the thus established relative position of inner cap (32) with respect to outer cap (34) is preserved by virtue of the hardening of the intermediate body (36) that takes place during the subsequent cooling of the intermediate body (36).

Description

[0001] Description

[0002] Method for producing a dental prosthesis

[0003] The invention relates to a method for producing a dental prosthesis which is provided with a number of matrix elements corresponding to each of the matrix elements for removable fixation to a number of teeth, each crowned with a male element, in the mouth of a patient.

[0004] When teeth are lost, the usual goal is to replace them or at least close the gaps created by the loss. This can be achieved, for example, with so-called bridges. The teeth adjacent to the gap are filled, and a crown is fabricated, which replaces the lost teeth with appropriate bridge elements. The bridges are mechanically anchored to the ground-down teeth. A pendant can also be attached to a bridge, which provides support for a free-end situation. This type of situation can also be treated with removable clasp dentures, which are usually supported on natural teeth.

[0005] In addition to bridgework, lost teeth can also be replaced with endosseous implants. These typically use threaded pins as artificial tooth roots, to which the prosthesis can be anchored. This anchorage can also be fixed (screwed, cemented, or bonded) or removable. With removable anchorages, the adhesive forces that hold the prosthesis in position are usually based on a vacuum effect, friction, and / or retention.

[0006] When too few teeth remain in the patient's mouth, other solutions are usually used. One option is to remove all remaining teeth and use mucosal-supported dentures. These are inexpensive, but offer poor chewing comfort for the patient and are usually accompanied by bone loss in the upper and lower jaw. The remaining teeth and / or endosseous implants are often used as support for removable restorations. A wide variety of solutions are available for this. Clasp dentures, electroplating techniques on implants or implant bars, conical clasp systems, ball-head anchors, silicone-metal matrix-patrice systems, and other systems can be used.

[0007] In particular, so-called telescopic systems can be used, in which a dental prosthesis is removably attached to so-called telescopic crowns. These telescopic crowns are double crowns in which a "lower" or base crown, also referred to as the "primary crown", in particular a male element, is firmly attached to a suitably prepared, e.g., ground, tooth in the manner of a conventional crown. On its upper side, this male element forms a contact pin to which an "upper" crown segment or matrix element, also referred to as the "secondary crown", can be attached, for example, clicked or clipped on, in a detachable or removable manner. The crown segments thus form a type of matrix-male system. The upper crown segment, forming the matrix, then serves as the support for the prosthetics, and the detachable connection between the crown segments makes the entire denture removable.Commonly used are parallel or conical telescopes, which can be cast, milled or designed as a gold-plated prosthesis.

[0008] During the production of all these systems, the patient's oral situation is usually recorded in a first step, for example by taking an impression using suitable impression material. The oral situation is then usually transferred to a physical model, such as a plaster model, or a virtual model. Using this model, the dental technician can then fabricate the prosthetics according to the situation and requirements, so that they can later be inserted into the patient's mouth with the greatest possible fit. The accuracy of fit is a very important factor, as a high level of fit is a prerequisite for the prosthesis to sit securely in the patient's mouth. Furthermore, a high level of fit also naturally requires a high level of comfort for the patient, so that they can feel as comfortable as possible with the prosthesis.The more precisely the prosthesis is manufactured, the more firmly it can fit in the patient's mouth, which in turn leads to a very high level of wearing and chewing comfort. In contrast, the more flexible the removable fixation is, the more loosely it fits in the patient's mouth. While this simplifies the manufacture of the prosthesis and reduces manufacturing costs, a particularly high level of fit is usually sought after, taking these aspects into account. A problem that has emerged in this context is that the described transfer of the patient's situation to a physical or virtual model can significantly contribute to undesirable fit inaccuracies.

[0009] In order to provide a highly precise matrix-patrice system, the matrices anchored in the denture can be cemented or bonded in the patient's mouth to avoid inaccuracies. However, this involves increased effort and correspondingly higher costs.

[0010] Furthermore, all these systems are subject to wear and tear due to repeated removal and insertion in the patient's mouth, which also varies depending on the system. This wear and tear should be kept to a minimum when designing new concepts.

[0011] Another function of removable restorations is that the adhesive strength should be reproducible and give the patient the feeling of having fixed teeth, while at the same time not jamming the denture when removed. This means that the adhesive strength should not be too high and, if possible, should be independent of the patient's previous purchasing power.

[0012] Currently, among the telescopic systems of the type described, matrix-patrice systems based on a gold-plated matrix on a ceramic matrix represent the most popular and, in terms of their properties, the best variant in terms of comfort and balance in the areas of adhesion or adhesive force and wear. Within the matrix-patrice system, they achieve the highest fit accuracy and thus also have optimal suction or negative pressure effect with regard to adhesive forces. Due to the high-precision fit, they also have very low wear. Since the system is usually conical in the area of ​​the matrix-patrice connection and rests occlusally, there is no conical self-locking in the system, which also prevents jamming during removal. The only disadvantages of these systems are the very complex manufacturing process and the very high price.

[0013] The high cost is justified as follows: The dentist takes an impression of the patient's situation. The dental technician creates a patient model. The patrices are acquired or purchased, particularly on natural teeth using the CAD / CAM process (or previously cast). The matrices are then fabricated or, in some cases, purchased prefabricated on implants. A metal framework is then manufactured. The entire assembly is then sent to the dentist. The dentist fixes (screws, glues, or cements) the patrice elements onto the teeth. They then glue or cement the matrix elements into the framework. This carries the risk of the matrix-patrice system becoming stuck together in the patient's mouth, which can lead to time-consuming removal. The entire assembly is then sent back to the dental technician so that the dentist can create the finished prosthesis on the framework.Only then is the prosthesis finished and can it be finally inserted into the patient's mouth. The advantage, however, is that the inaccuracies of the usually four-matrix-patrix systems can be minimized to a great extent by transferring the model from the patient.

[0014] Currently, attempts are being made to replace the gold electroplating matrix with a plastic matrix, usually milled or 3D-printed. PTFE, PEEK, PPS, and plastics with similar properties are commonly used.

[0015] German patent application No. 10 2022 127 865.4, filed with the same date priority and entitled "Telescopic Crown," describes a telescopic crown of the type mentioned above that is significantly improved compared to the prior art, which avoids the aforementioned disadvantages and allows the provision of a dental prosthesis with a particularly high degree of precision at comparatively low cost. In this improved telescopic crown, the matrix element is constructed in several parts and comprises an inner cap that can be plugged onto the patrix element and an outer cap that can be attached to the dental prosthesis. An intermediate body made of thermoplastic material is arranged in the space between the inner and outer caps, connecting them together.

[0016] The underlying idea is that a high degree of accuracy of fit of the prosthetic in the patient's mouth can be achieved by only relatively roughly adapting the components used to create the prosthetic to the patient's oral situation during the preparation phase, with the final adaptation and fine-tuning only taking place during insertion into the patient's mouth and in response to the resulting restoring forces and the like. To make this possible, one of the components, i.e. the matrix or the patrix, should be designed in such a way that final positioning and alignment only takes place during insertion into the oral cavity. For this purpose, the patrix or preferably the matrix is ​​​​designed to be made of several parts so that a first part - in this case the outer cap of the matrix - can already be firmly attached to the denture during preparation.The alignment of the inner cap relative to the outer cap, and thus the final positioning, should then occur during insertion in response to the forces occurring in the oral cavity. For this purpose, the inner cap of the matrix can be connected to its outer cap via an intermediate body which, according to the concept of the invention, gradually solidifies during or immediately after insertion, starting from an initially deformable state. Solidification should occur during insertion so that influences from the oral environment can be absorbed and the components can automatically align themselves in an optimized manner in response to the oral situation. Subsequently, i.e., after solidification, the optimized alignment of the components thus achieved should be suitably fixed.

[0017] For example, the inner cap could be connected to the outer cap via a cement or adhesive bond. If there is enough volume for the cement or adhesive, this would offer sufficient flexibility for optimising the positioning and alignment of the components while the cement or adhesive is still solidifying. Alternatively, the intermediate body could be made from a thermoplastic material. Before insertion, the intermediate body can be heated up accordingly so that it softens to a certain extent and thus becomes malleable. Insertion can then take place in this state so that the inner and outer caps are aligned accordingly to the fine details of the oral situation. Upon cooling, the intermediate body solidifies again while retaining this geometry, thus ensuring that the desired optimised positioning is suitably fixed.

[0018] The telescope system mentioned particularly and preferably comprises one or more of the following aspects:

[0019] It is a matrix-pattern system

[0020] The patrix is ​​formed by a cap fixed on a natural tooth.

[0021] The matrix is ​​formed by a cap which is placed over the patrix.

[0022] The die is made up of several parts and comprises an outer and an inner cap, between which a deformable, preferably thermoplastic intermediate body is arranged

[0023] For the patrix, which is designed as a cap on a natural tooth, the prepared tooth determines the cross-section and functional height. The preparation angle is advantageously 1° to 6°, particularly preferably 2° to 4°.

[0024] The patrix as a cap on a natural tooth is preferably made of titanium or titanium alloy, zirconium or zirconium alloy, tantalum or tantalum alloy, a non-precious metal or a ceramic based on zirconium dioxide (ZrO2) and or aluminum oxide (Al2O3) and or a silicate ceramic or an alloy of the metals or a mixture of the ceramics Adhesion I the adhesive force between patrix and matrix is ​​based on a conical design (angle bisector = 2° - 10°; 2° - 8°; 4° - 6°) via suction effect

[0025] Adhesion / adhesive force between patrix and matrix is ​​based on a conical design (2° - 10° ; 2° - 8° ; 4° - 6°) via suction effect and additional retention by means of at least one circular undercut

[0026] The undercut is cut into the cone of the body part as a circumferential bead and preferably as a circumferential groove

[0027] The undercut is located in the conical area. Preferably, it is positioned in the apical half, the apical third, or the apical quarter of the conical portion.

[0028] The adhesion / holding force can but does not have to be additionally supported by a conical self-locking mechanism.

[0029] The male part and / or in particular the female part of the thus improved telescope system is thus designed as a multi-part system, which, viewed in longitudinal section, can be regarded as a multi-layer system, preferably a double or triple layer system. In a design designed as a double-layer system or a two-part system, this preferably consists of an outer cap made of a metallic base material or preferably of a plastic, and particularly preferably of a biocompatible high-performance plastic, and the thermoplastic intermediate body facing the male part. Both plastics are preferably autoclavable, i.e., temperature-resistant up to at least 135°C. The plastic facing the male part is preferably designed with regard to its material selection for

[0030] - low water absorption

[0031] - high mechanical strength

[0032] - high wear resistance

[0033] The plastic facing away from the male part, forming the outer cap, could be softer than the thermoplastic plastic facing the male part.

[0034] In an embodiment as a three-layer system or three-component system, the matrix element is designed according to one aspect of the invention:

[0035] - Like the double-layer system and additionally an inner cap facing the male part - the inner cap facing the prosthesis can be easily cemented / bonded to it - and is mechanically stronger than the other two plastics

[0036] - Easily mechanically bonded to the plastic facing the male part.

[0037] - Preferably made of titanium, zirconium, tantalum, or an alloy of at least one of the metals.

[0038] The inner cap of the matrix element should be able to be tilted or displaced relative to the outer cap during final alignment, i.e., during curing of the thermoplastic intermediate body. Advantageously, and according to one aspect of the invention, the inner cap is made of a plastic, preferably a high-performance plastic. According to one aspect of the invention, this plastic should have a softening temperature significantly above the softening temperature of the thermoplastic intermediate body, preferably 20, 25, or even 50% higher. Furthermore, the plastic forming the inner cap should have comparatively high abrasion resistance and mechanical strength, so that repeated removal and reinsertion of the telescopic crown is possible even without significant wear of these components. The inner cap is particularly preferably made of PEEK or a comparable plastic.

[0039] The thermoplastic intermediate body provided according to this improvement can also be designed in the form of a layer, i.e. as a thermoplastic layer.

[0040] The introduction of such a thermoplastic layer can compensate for the inaccuracy of fit between the patient situation and the model situation at the dental technician.

[0041] The present invention is based on the object of providing an improved method for producing a dental prosthesis with which a dental prosthesis with a particularly high degree of fitting accuracy can be produced in a simplified manner.

[0042] This object is achieved according to the invention with a method for producing a dental prosthesis which is provided with a number of matrix elements corresponding to one of the matrix elements for removable fixation to a number of teeth, each crowned with a male element, in the mouth of a patient, wherein the or each matrix element is designed in several parts and comprises an inner cap which can be plugged onto the associated male element and an outer cap which is attached to the dental prosthesis, and wherein in the space between the inner and outer caps there is arranged an intermediate body made of thermoplastic material which connects them to one another, in which intermediate body, for the precise alignment of the inner cap relative to the outer cap of the respective matrix element, is heated to a temperature above its softening temperature and thus made deformable,and then, using the deformability of the intermediate body, the inner cap is aligned relative to the outer cap with regard to an optimized fit, taking into account the actual dentition situation in the patient's mouth, before the thus adjusted relative position of the inner cap with respect to the outer cap is preserved as a result of the solidification of the intermediate body that begins during the subsequent cooling of the intermediate body.

[0043] Alternatively, the above-mentioned object is achieved according to one aspect of the invention with a method for producing a dental prosthesis which, for removable fixation to a number of teeth, each crowned with a male element, in the mouth of a patient, is provided with a number of matrix elements corresponding to one of the male elements, in particular using multi-part matrix elements, each comprising an inner cap which can be plugged onto the associated male element and an outer cap which is attached to the dental prosthesis, wherein in the space between the inner and outer caps there is arranged an intermediate body made of thermoplastic material which connects them to one another, wherein, based on intraoral data reflecting the actual dentition situation in the patient's mouth, those male elements are selected from a number of basic male element types stored in a component library,which allow a reliable fixation of the prosthesis with the lowest possible removal of tooth substance, and whereby the required grinding of the teeth is determined on the basis of this selection and made available to the practitioner as an instruction manual.

[0044] The invention is based on the idea that a further improved and simplified manufacturing process should specifically utilize the possibilities and degrees of freedom provided by the aforementioned improved design of the telescopic crowns. In particular, this can take advantage of the fact that the multi-part design of the matrix elements means that the fine alignment and adjustment of the components relative to one another is only possible at a relatively late stage, i.e. when the crown is inserted into the patient's mouth. Until then, it is possible to work with relatively roughly prefabricated components. This also allows, among other things, the use of standard components that can be easily produced in larger quantities and are only finely and precisely aligned and positioned in the final production step, using the degrees of freedom enabled by the thermoplastic intermediate piece.Such standard components can thus be stored as basic types in a library and made available for selection. According to aspects of the invention, the manufacturing process for the patrixes on natural teeth, including the software and library, is thus designed according to the following aspects and criteria:

[0045] Providing natural teeth intended as abutments for prosthetics with appropriate patrices or prefabricated patrice caps fundamentally presents a very significant challenge. The dentist must prepare the tooth stumps in order to be able to use them as abutments at all. This would require the teeth to first be prepared in such a way that a prefabricated patrice cap can be precisely fixed. The height, cone angle, and cross-section of the ground tooth, and therefore the tooth as a whole, would have to be adapted as precisely as possible to the inner lumen of the patrice cap. In addition, the intended insertion angle of the prosthesis must also be taken into account when attaching the prosthesis to the abutments. This is particularly important because three to eight (preferably four to six) abutments would have to be prepared in such a way that, after the patrice caps have been fixed, the prosthesis can be inserted without tension.

[0046] The object posed here is achieved according to an aspect of the invention considered to be independently inventive by providing a virtual library of patrice designs in the form of basic types, which comprises ground abutments in the corresponding regions (anterior tooth, canine tooth, posterior tooth, upper jaw and lower jaw). It is advantageous if there are preferably a number of patrice dimensions per region. The practitioner then only has to prepare the tooth stumps in such a way that one of the virtually provided library patrice caps with sufficient material thickness would fit over this ground tooth stump. In a CAD-CAM process, it is then possible to position the patrice caps of all abutments on the ground tooth stumps in optimal alignment with one another and to manufacture them accordingly.

[0047] To make this possible, one aspect of the invention provides that the practitioner scans the teeth intended as supporting pillars in advance, if possible using an intraoral scanner (alternatively, a situation model could be created using a conventional impression, which is then digitized using a scanner). The entire jaw is preferably scanned. Software then calculates for which patrix caps (for which prefabricated matrices should then be available) the practitioner needs to remove the least amount of tooth structure, i.e. for which the tooth or stump needs to be ground the least. If a complete intraoral scan is available, the software can also take into account the optimized insertion direction as described above. The practitioner is then shown on a screen in the program how much needs to be removed, ground, or ground away from which tooth or stump.The practitioner can now begin grinding. For verification purposes, the practitioner can perform a repeat intraoral scan after completing the initial grinding process. This time, it is only necessary to capture the ground tooth and the immediate surrounding area to determine the achieved shape. If this is insufficient, the software will indicate this and prompt the practitioner to perform a repeat, complete jaw scan. This allows the practitioner to iteratively grind the teeth or stumps until the preparations have a dimension such that the corresponding male coping, with its minimum wall thickness, fits the tooth stump.

[0048] The exchange of information during grinding—i.e., where and how much needs to be removed or ground away—can also be achieved using other preparation testing techniques. It is particularly worth mentioning that there are methods that, in addition to the oral situation, also record the position of the contra-angle handpiece including the grinding tool, and can thus even record the change in shape of the tooth or tooth stump during tooth preparation. This is displayed to the practitioner on a monitor, allowing the preparation step to be optimized in terms of time. Thus, a repeat scan of the tooth or tooth stump is only necessary after preparation is complete for a final check.

[0049] Finally, either a conventional impression or an intraoral scan of the entire jaw is taken. The tooth stumps are then overlaid with the corresponding male copings using CAD-CAM software. This results in corresponding male copings with a virtually prefabricated outer design (suitable for prefabricated matrices) and a corresponding inner design tailored to the tooth stump (suitable for the individually ground tooth stump). These hybrid copings (prefabricated on the outside - customized on the inside) can then be manufactured in a grinding process from the green compact, white compact, or a pre-sintered ceramic and subsequently sintered if necessary. In a particularly cost-effective variant, appropriate form milling cutters are available for the milling process for the outer design of the virtual prefabricated male copings to optimize accuracy, surface quality, and production speed.These patrices can of course also be made from a metal (titanium, zirconium, tantalum or an alloy with a main component of one of the metals), a non-precious metal alloy (e.g. chromium-cobalt-molybdenum) or a precious metal alloy. Other machining processes or additive processes such as laser sintering or similar processes are also suitable for production. If a CT scan, a DVT or another 3-dimensional recording system (e.g. MRI) is carried out prior to preparation, it is possible to record the cavities of the tooth root, i.e. the root canals, of the teeth or tooth stumps to be ground. In a particularly advantageous embodiment, this data can be superimposed with the intraoral scan in order to avoid the tooth substance removal required for the placement of the patrice cap selected being so great that a perforation of the root canal occurs.This would cause significant damage to the tooth, which would require root canal treatment.

[0050] Furthermore, it is also possible to evaluate existing 3-dimensional data about teeth, for example, using artificial intelligence (Kl), in order to make a statement about the probability of a root canal perforation using only the intraoral scan. The overall system would also be capable of anonymously documenting whether or not a root canal perforation has occurred using artificial intelligence (Kl). This data could then be made accessible to all other users via the system in anonymized form with an appropriate internet connection, further optimizing system security.

[0051] The dental technician can then complete the entire prosthesis on his model. The finished prosthesis can deviate from the actual patient situation in terms of the positions of the male parts relative to the female parts by a range of, for example, 50 μm to, for example, 250 μm. The introduction of the thermoplastic layer or the thermoplastic intermediate body provided according to one aspect of the invention is able to compensate for this. In order to be able to achieve this compensation, the thermoplastic layer should preferably have a corresponding thickness of at least 250 μm around the layer surrounding the male part. During insertion into the patient's mouth, the thermoplastic layer is thermally brought above the softening point or the softening interval so that it is deformable. If the prosthesis is then inserted into the patient's mouth and the patient bites, the softened thermoplastic layer or intermediate body align themselves.The softened thermoplastic intermediate body "floats" the matrices precisely onto the patrixes. After cooling, the thermoplastic layer solidifies again, and the aligned positions of the matrices are retained. This process can be repeated several times as needed, even after extended wear.

[0052] Before the final prosthesis or prosthetic is developed, the patrix designs to be used later are preferably defined in CAD during the grinding of the tooth stumps, in a process considered to be independently inventive. Patrice designs already available in CAD are selected for which corresponding matrices are available. These are aligned for an optimized insertion direction of the finished prosthesis or prosthetic based on the data of the oral situation (remaining dentition, mucous membrane, opposing jaw) acquired via the intraoral scanner, and are aligned with the ground tooth stump. From this, the cap to be manufactured is planned and fabricated. This cap forms a matrix opposite the tooth stump and a patrix opposite the prosthesis or prosthetic, which engages the matrix of the detachable connection to the prosthesis or prosthetic.

[0053] According to aspects of the invention, one of the three embodiments described below can be used for the dental laboratory procedure:

[0054] 1. Classic process with the already manufactured cap

[0055] After the copings are fabricated, they are temporarily attached to the tooth stumps of the physical master model (plaster model, printed plastic model, etc.). The matrix elements are then attached to the primary crowns. The prosthesis is then planned, designed, and fabricated on these. Finally, the fabricated prosthesis or prosthetic is bonded or cemented, preferably to the master model, to the matrix elements.

[0056] 2. Procedure I with primary crown analogues integrated into the master model:

[0057] In a second variant, the corresponding prefabricated primary crowns are integrated into a printed master model. The matrix elements are then attached to the primary crowns. The prosthesis is then planned, designed, and fabricated on these. Finally, the fabricated prosthesis or prosthetic is bonded or cemented to the matrix elements, preferably on the master model.

[0058] 3. Procedure II with primary crown analogues integrated into the master model:

[0059] In the third variant, the primary crowns are fabricated and bonded or cemented before the master model is created. After the tooth stumps have been prepared, the primary crowns are fabricated directly by the dentist (“chairside”) or in a nearby dental laboratory and bonded or cemented in the same appointment. An intraoral scan or conventional impression, preferably with appropriate impression copings, can then be taken on the primary crowns. A master model (plaster model, printed plastic model, etc.) with integrated primary crown analogs can then be fabricated. The matrix elements are then attached to the primary crowns. The prosthesis is then planned, designed, and fabricated on these. Finally, the fabricated prosthesis or prosthetics is finally bonded or cemented to the matrix elements, preferably on the master model.

[0060] In a particularly preferred embodiment, the thermoplastic layer or intermediate body is made of thermoplastic elastomer or thermoplastic silicone. The advantage is that the retention function, as a snap-fit, is more easily adjustable in force. Furthermore, an elastomer layer will not fatigue as quickly and its adhesive strength will not decrease. Furthermore, this also contributes to minimizing wear in the matrix-pattern system.

[0061] With regard to the shape and cross-section of the male-male system, several alternatives are conceivable in the inventive design. The simplest cross-sectional shape for the male-male system is considered to be a round design. However, depending on the required force transmission area, an oval design (elliptical, trioval, quadoval) may also be preferred. With a round design, the space requirement increases with increasing cross-sectional diameter. The prosthesis fixed to the female-male system is also spatially limited in its ability to integrate the female, particularly in the buccal-palatal or buccal-lingual plane. In contrast, more space is available in the mesio-distal extension, since this is the orientation of the dental arch.In order to utilize the available space particularly effectively, oval designs may be advantageous according to one aspect of the invention, as they would allow for a larger force transmission area, friction area, and retention area. The radii of the cross-sections should preferably remain as oval as possible and should not contain any corners, straight sections, or concavely curved areas. Furthermore, radii smaller than 1.0 mm and especially smaller than 0.5 mm are unsuitable, as greater wear can be expected in these cases during retention.

[0062] Especially when anchoring to natural teeth, it may even be necessary to deviate from the round shape, since the remaining dentition of the different patients may not be known prior to the actual treatment. Natural teeth are usually not round, but oval in cross-section. This means that a ground tooth does not have a round cross-section, and consequently a round patrice design is rarely suitable. Rather, according to one aspect of the invention, oval / elliptical cross-sections can be advantageous and suitable in the anterior region, trioval for canines, and more quadoval in the posterior region. These can, of course, also have some straight or concave areas.

[0063] According to one aspect of the invention, a retention provided by the geometry is primarily provided in a mesio-distal orientation so that the caps on the stumps / abutments can be designed with comparatively thin walls in the buccal-palatal or buccal-lingual plane. The space required for the retention elements in the patrix preferably consists of a notched groove, which is then preferably only provided in the anterior and posterior areas where sufficient space is available. Accordingly, round or oval retentions are preferred as shapes / designs in the matrix-pattern system for retention, preferably circumferential, but not necessarily fully circumferential, especially in the case of non-circular cross-sections.

[0064] Preferably and according to one aspect of the invention, for the planning and design of the dental prosthetics according to the above explanations, basic types for the patrices and patrice shapes to be considered are determined and made available for selection in the library.

[0065] According to an aspect of the invention considered to be independently inventive, when using the telescopic crowns, the thermoplastic intermediate piece is heated to a temperature above its softening temperature immediately before insertion into the patient's mouth for the purpose of adjustment and position optimization, so that it becomes correspondingly deformable. According to an aspect considered to be independently inventive, the use of a heating device is provided for this purpose, which is provided with a number of heatable contact plugs in a heating area, the outer contour of which is adapted to the contour of the male parts of the telescopic system. Thus, such a contact plug can be inserted into the corresponding female part instead of the actual male part.For heating, the respective die element can then be plugged onto one of these contact plugs, and subsequently, by heating the contact plug, the thermoplastic intermediate body of the die element can be heated to a temperature above its softening temperature.

[0066] The softening temperature of the thermoplastic layer or the thermoplastic intermediate body is selected, in particular through a suitable choice of material, above approximately 135°C. This is the temperature of common and conventional autoclaves, with which, for example, prostheses are autoclaved for preparation for use or for disinfection. According to one aspect of the invention, the material parameters of the intermediate body are selected such that, at the usual temperatures during such autoclaving, thermoplastic softening does not occur. So that even during such autoclaving, the position of the inner cap facing the male part does not change relative to the position of the outer cap facing the denture, and the position previously established according to the concept of the invention is also not changed during autoclaving.The lowest acceptable softening temperature for the material of the intermediate body should therefore preferably be in the range of 70°C - 80°C. These are temperatures that a patient is unlikely to reach even when cleaning their dentures using the home faucet, thus ruling out deposition of the inner cap facing the male part due to deformation of the intermediate body during daily use.

[0067] When heating the components and immediately inserting the prosthesis for the purpose of fine-tuning the components, especially the inner cap relative to the outer cap, there is always a risk of damage to the patient's mucosa and / or dental tissue (nerve) and / or bone. For this reason, the softening temperature is preferably chosen to be relatively low. In addition, the heat capacity of the thermoplastic material forming the intermediate body should be relatively low, which is certainly the case due to the thinness of the three-layer system.

[0068] To achieve the softening temperature and prevent excessive cooling before the final positioning of the inner cap facing the male part, it would be desirable to heat the entire prosthesis to the specified temperature. However, this is rather unsuitable for the intended treatment, as this would require the prosthesis to be inserted into the patient's mouth at a temperature of at least 70°C - 80°C. Even at temperatures above 40°C - 50°C, the patient would certainly experience severe pain, and above this temperature, burns could even be expected. For this reason, according to one aspect of the invention, only the intermediate body, or the two- or three-layer system of the male part forming it, is heated accordingly.

[0069] To achieve this object, it has been found that, according to one aspect of the invention, heating should occur via the inner cap facing the male part. For this purpose, the heating device described above is particularly advantageous, as it has a heating element, preferably an electric heating element, geometrically adapted to the shape of the female part and thus pluggable into it. Telescopic dentures usually have two to six, and preferably four, abutments, each with one of the aforementioned male-female connections. Therefore, the heating device is preferably equipped with a plurality, preferably six, of the aforementioned heating elements or contact plugs, so that all the female parts of a dental prosthesis can be heated simultaneously and thus prepared for insertion.

[0070] By applying a defined amount of heat energy over a defined period of time, the amount of heat required to soften the intermediate body or the thermoelastic layer can be introduced into it, enabling the fine alignment of the layer facing the male molds. These heating elements, or male molds, are preferably made of a metal, preferably one with high thermal conductivity, particularly gold, for optimized heat dissipation. Their geometry is preferably as identical as possible to the actual male molds. Small grooves in the axial direction may be provided solely to facilitate removal, so that no negative pressure can build up after heating. If the thermoplastic layers are heated, removal could damage them if negative pressure is present.Furthermore, a handle is preferably formed behind the actual heating male part to allow the heating male parts to be easily inserted into the female parts and removed again.

[0071] Preferably, the heated males are equipped with an internal electric heater with integrated temperature control. This ensures that overheating cannot occur and thus damage the matrix-male system or the prosthesis itself. This control involves temperature sensors integrated into the heated males. However, the heated males can also be equipped with another heat source or be powered by an external heat source. Furthermore, it is also possible for the heated males to simply heat the thermoelastic layer using another energy source without being heated themselves.

[0072] The heating male parts are preferably connected to a central temperature control unit via cables. This unit preferably contains four or six connections in order to be able to control four or six heating male parts simultaneously. Alternatively, and depending on the intended use, such a unit could also be provided with a larger number of connections, for example 6, 8, or 10. According to one aspect of the invention, there should be at least as many connections as are usually provided with supporting pillars in a prosthesis. This is at least three or four, but can also be 6 to 8. The heating male parts are preferably provided directly with a cable, but are connected to the control unit via a removable plug. In a particularly preferred embodiment, the heating male parts are equipped with rechargeable batteries that are only located in a charging station. In this case, the temperature control unit is integrated into the heating male parts.

[0073] With regard to their shape, it is advantageous for geometrically different die-male-male systems to also provide these different geometries for the heating males.

[0074] According to a further aspect of the invention, which is considered to be independently inventive, a ceramic material can be provided for the patrix. Ceramic is particularly suitable as a patrix material for aesthetic reasons alone. For example, the patient usually feels more comfortable with a removed denture if the supporting abutments are tooth-colored rather than metallic. Metals are also good heat conductors. If the thermoplastic layer or the thermoplastic intermediate body is heated to compensate for the fit, this heat is also transferred to the patrix upon cooling. Furthermore, with natural teeth, there is a risk that the heat will be transferred to still vital teeth, causing damage to the dental nerve.

[0075] Although the thermal capacity of the thermoplastic layer and the male part is preferably chosen to be rather low, potential damage cannot currently be completely ruled out. Consequently, materials with relatively low thermal conductivity are particularly suitable as male part materials. Metal veneers made of plastic or ceramic are preferred. However, it is particularly important to note that male part caps made of solid ceramic, especially Al2O3 or ZrO2 ceramic, which are excellent heat shields, should be used preferentially.

[0076] According to an aspect considered to be independently inventive, metallic particles can be embedded in the thermoplastic intermediate body. The intended heating, up to the point of softening the thermoplastic layer, can then be achieved by induction and thus, if necessary, without contact.

[0077] According to a further aspect considered to be independently inventive, magnetic particles such as iron or iron oxide can be embedded in the thermoplastic intermediate body. The intended heating can then be carried out, in particular by generating friction, with an alternating magnetic field and thus also without contact. According to a further aspect considered to be independently inventive, the inner cap facing the patrix can be designed to be "floating" before insertion in the patient's mouth, i.e. instead of the thermoplastic intermediate body, a hollow space can initially be provided between the inner and outer caps. The dental technician then creates an access channel which is filled by the dentist with an adhesive or elastomer or thermoplastic material or the like during insertion.

[0078] According to the embodiments described above, the matrix designed according to the concept of the invention is essentially to be regarded as a three-component component (or, viewed in cross-section, as a three-layer system) comprising the components inner cap, outer cap, and the intermediate body arranged between them. According to a further aspect of the invention, a further, i.e. fourth, component or layer can additionally be provided. In this case, according to this aspect of the invention, an outer fourth layer or component can be provided as the fourth layer, which in turn surrounds the outer cap on the outside and enables a detachable connection of the matrix element to the prosthesis or dental prosthesis. This makes it possible for the matrix element to be mechanically mounted on the prosthesis or dental prosthesis and to be easily dismantled again without causing any damage. This makes it possible to first firmly anchor the matrix or cap in the prosthesis and, if necessary, e.g.After several years of wear, the matrix is ​​relatively easy to remove and replace with a new multi-part matrix system. This allows for a particularly simple service replacement of an inserted matrix, for example, when the matrix begins to wear. It is particularly important that the adhesive force in this system is significantly higher than that of the matrix-patrix system. It should be a type of locking mechanism that, when changing, only damages or destroys the matrix being replaced. A special tool in the form of pliers or something similar would be advantageous.

[0079] In a further embodiment considered to be independently inventive, the multi-part matrix element can comprise an intermediate body made of light-curing plastic instead of or in addition to the thermoplastic intermediate body. This intermediate body could, for example, be incorporated in an uncured, i.e., still deformable, state according to the previously described procedure, so that the inner and outer caps of the matrix can be suitably aligned with each other. After this has been achieved, the intermediate body could, for example, be cured using UV light, thus fixing the received position.

[0080] The advantages achieved with the invention consist in particular in the fact that completely prefabricated matrix-patrice systems can be produced on natural teeth in the manner according to the invention, in particular with a matrix that can be manufactured from metal and preferably from a ceramic using a CAD / CAM process. Furthermore, in this way, a system with reproducible adhesive force that is hardly dependent on the chewing force can be provided. The system exhibits very little wear, particularly due to the extremely high degree of accuracy of fit that can be achieved. Highly precise fits for a high level of wearing and chewing comfort can be achieved, and handling is simple and uncomplicated, i.e. the dental technician can fix the matrix in the prosthesis with minimized inaccuracy of fit in the patient's mouth. Furthermore, the system has a particularly small space requirement.

[0081] An embodiment of the invention is explained in more detail with reference to a drawing. In the drawing:

[0082] FIG. 1 schematically shows a telescopic system for attaching a denture in the oral cavity of a patient,

[0083] FIG. 2 shows a longitudinal section through a telescopic crown of the system according to FIG. 1,

[0084] FIG. 3 shows a telescopic crown according to one aspect of the invention in longitudinal section,

[0085] FIG. 4 shows a matrix element of the telescopic crown, as shown in FIG. 3, in an exploded view in perspective partial section,

[0086] FIG. 5 shows the matrix element of the telescopic crown, as shown in FIG. 3 in exploded longitudinal section,

[0087] FIG. 6 shows a side view of a male element of the telescopic crown shown in FIG. 3, and an inner cap of the female element, whose inner contour is adapted to the outer contour of the male element shown in FIGS. 4, 5,

[0088] FIG. 7 shows a male element and the associated female element in pairs in different cross-sectional geometries,

[0089] FIG. 8 shows a sequence of assembly steps of the matrix element shown in FIGS. 4 and 5 in partial section in perspective view,

[0090] FIG. 9 shows a sequence of assembly steps of the die element according to FIGS. 4 and 5 in longitudinal section, FIG. 10 shows the die element according to FIG. 9d with a "tilted" outer cap,

[0091] FIG. 11 shows an alternative embodiment of a matrix element in longitudinal section,

[0092] FIG. 12 shows a section of a heater, and

[0093] FIGS. 13-17 each show an enlarged view of a contact plug of the heater according to FIG. 12.

[0094] Identical parts are provided with the same reference numerals in all figures.

[0095] The telescopic system 1 (see FIG. 1) is used for the removable attachment of a dental prosthesis 2 in the oral cavity of a patient. In the exemplary embodiment, a complete upper jaw prosthesis is shown as the dental prosthesis 2; however, other prostheses could of course also be provided alternatively, such as a bridge that closes a gap between several teeth of a remaining dentition, or even individual prostheses to replace a single tooth. The dental prosthesis 2 is designed for a detachable connection to a number of supporting pillars that are firmly arranged on the upper jaw 4 and thus in the oral cavity of the patient. In the exemplary embodiment shown, the supporting pillars are teeth 6 of a remaining dentition that remain in the patient's oral cavity and whose surfaces have been suitably ground down.

[0096] The telescopic system 1 comprises a number of so-called telescopic crowns 10 - in the exemplary embodiment corresponding to the number of ground teeth 6 of the remaining dentition - with which the dental prosthesis 2 is removably attached to the upper jaw 4 and thus in the patient's oral cavity. Such a telescopic crown 10, as shown in a conventional design in longitudinal section in FIG. 2a in a single version and in FIG. 2b in longitudinal section as a fastening means for the dental prosthesis 2, essentially represents a double crown system. On the one hand, this comprises a "lower" or base crown 12, also referred to as the "primary crown", which is firmly attached to a suitably prepared, e.g., ground, tooth 6 in the manner of a conventional crown. The primary crown 12, which is also visible in the illustration in FIG. 1 for the teeth 6 shown there, is shown in the illustrations in FIG. 2 in the state attached to the respective tooth 6.

[0097] The primary crown 12 is designed, in a quite conventional manner, as a male element 14, which forms a contact pin 16 on its surface. An "upper" crown segment or female element 18, also referred to as a "secondary crown," can be detachably or removably attached to the male element 14 as the second essential component of the telescopic crown, for example, by clicking or plugging it on. In FIG. 2a, the sliding-on process is indicated by the arrows 20, whereas in FIG. 2b, the telescopic crown 10 is shown in the state with the female element 18 completely pushed onto the male element 14. In the type of matrix-pattern system of the telescopic crown O formed by the crown segments 14, 18, the “upper” crown segment 18 forming the matrix serves as a support for the dental prosthesis 2, which is suitably firmly connected to the matrix elements 18.

[0098] With telescopic systems 1 of the type described, the accuracy of fit of the dental prosthesis 2 in the patient's mouth is an important factor, since a high accuracy of fit is a prerequisite for a secure fit of the prosthesis 2 in the patient's mouth. Furthermore, a high accuracy of fit naturally also requires a high level of comfort for the patient, so that they can feel as good as possible with the prosthesis 2. The more precisely the prosthesis is manufactured, the more firmly it can fit in the patient's mouth, which in turn leads to very high wearing and chewing comfort. However, with regard to common manufacturing methods, which usually first determine the dental situation in the patient's mouth and then transfer it to a physical or virtual model, based on which the restoration is then planned and manufactured, undesirable inaccuracies in the fit are to be expected.

[0099] To take this into account, according to one aspect of the present invention, a design for a telescopic crown 30 is provided, as shown in longitudinal section in FIG. 3, which allows for particularly precise fabrication of the double crown system. The inventive design of the telescopic crown 30 is based on the concept of manufacturing the essential components of the double crown system with an accuracy considered acceptable and then, after pre-assembly of the components, inserting them into the patient's mouth with a certain degree of flexibility and formability. There, in response to the actual oral situation and / or taking into account current data characteristic of the intraoral oral situation and the restoring and shear forces occurring during insertion, allowing the final positioning of the components adapted to the actual oral situation and then fixing them.

[0100] For this purpose, the telescopic crown 30 according to the invention, shown in FIG. 3, comprises as essential components, comparable to the conventional design of the telescopic crown 10, on the one hand a male element 14 intended for mounting or crowning on a residual tooth 6 and, on the other hand, a corresponding matrix element 18 which can be plugged onto the male element 14 and firmly connected to the dental prosthesis 2. In contrast to the conventional design in the telescopic crown 10, according to one aspect of the present invention, the matrix element 18 in the telescopic crown 30 is designed in several parts and comprises an inner cap 32 which can be plugged onto the male element 14 and an outer cap 34 which can be attached to the dental prosthesis 2, wherein in the space between the inner and outer caps 32, 34 an intermediate body 36 made of thermoplastic material is arranged which connects these to one another.This multi-part design of the matrix element 18 is particularly clearly visible in the exploded view in the perspective partial section in FIG. 4 and in the longitudinal section in FIG. 5.

[0101] This multi-part design using a temporarily deformable intermediate body 36 or a temporarily deformable intermediate layer makes it possible for the final positioning and alignment of the components to one another, in particular the inner cap 32 and outer cap 34, to only take place during the insertion of the telescopic crown 30 into the oral cavity. As part of the preparation for insertion, the outer cap 34 can thus already be firmly mounted on the denture 2. For insertion, the thermoplastic intermediate body 36 is then heated beforehand to above its softening temperature so that it is deformable. Insertion can then be carried out in this state so that the inner and outer caps 32, 34 align themselves to one another according to the fine details of the oral situation and in response to the resulting pressure and positioning forces, with the intermediate body 36 deforming.The alignment of the inner cap 32 relative to the outer cap 34, and thus the final positioning, is thus adjusted to the actual conditions in the oral cavity. The intermediate body 36 can then cool and solidify again while maintaining its assumed shape and thus its underlying position. Thus, after solidification, the optimized alignment of the components thus recorded is fixed.

[0102] Thus, the production of the dental prosthesis 2 can be carried out by heating the intermediate body 36 to a temperature above its softening temperature for the precise alignment of the respective inner cap 32 relative to the outer cap 34 of the respective matrix element 18, and thus making it deformable, and then, using the deformability of the intermediate body 36, aligning the inner cap 32 relative to the outer cap 34 with regard to an optimized fit, taking into account intraoral data reflecting the actual dentition situation in the patient's oral cavity.before the thus adjusted relative position of the inner cap 32 with respect to the outer cap 34 is preserved as a result of the solidification of the intermediate body 36 that begins during the subsequent cooling of the intermediate body 36. According to one aspect of the invention, the intermediate body 36 is preferably specifically adapted to the usual handling processes for use in dental treatments with regard to its choice of material and its material parameters. In particular, it is advantageously taken into account that autoclaving is common and widespread in such processes. According to one aspect of the invention, the material parameters of the intermediate body 36 are selected such that thermoplastic softening does not occur at the usual temperatures during such autoclaving.so that even during such autoclaving, the position of the inner cap 32 facing the male part 14 remains unchanged relative to the position of the outer cap 34 facing the denture 2, and the position previously established according to the concept of the invention remains unchanged even during autoclaving. The softening temperature of the thermoplastic intermediate body 36 is selected, particularly through a suitable choice of material, above approximately 135°C. This is the temperature of common and conventional autoclaves, which, for example, are also used to autoclave prostheses for preparation for insertion or for disinfection.

[0103] The male element 14 of the telescopic crown 30 is shown in a side view in FIG. 6a. In the exemplary embodiment, the male element 14 has a substantially round cross-section, although it can alternatively be designed with non-round cross-sections, for example oval, elliptical, trioval or the like, preferably adapted to the geometric conditions at the insertion site in the oral cavity. As can be clearly seen from the illustration in FIG. 6, the male element 14 has a circumferential groove 37 which, in interaction with an associated inner bead 38 on the inside of the inner cap 32, ensures retention when the inner cap 32 is applied and thus provides additional fixation. The connection system can therefore be designed in the form of a snap-in or locking connection, in which the female element 18 can be clicked or snapped onto the male element 14 via its inner cap 32. Suitable for this is, as can be seen from the illustration in FIG.6b, the inner contour of the inner cap 32 is adapted.

[0104] According to one aspect of the invention, a method is provided for producing the dental prosthesis 2, in which method those patrice elements 14 which allow reliable fixation of the prosthesis 2 with the lowest possible removal of tooth hard substance are selected from a number of basic patrice element types stored in a component library on the basis of intraoral data reflecting the actual dentition situation in the patient's mouth, and wherein the required grinding of the teeth 6 is determined on the basis of this selection and made available to the practitioner as an instruction manual. For the patrice elements 14, depending on the details of the oral situation, various basic types are considered, which are made available to the practitioner for selection. FIG.Figure 7 shows, by way of example, a number of geometric variants of the male element 14 in combination with the respective associated female element 18 with differently designed cross-sectional contours, as can be selected as needed depending on the insertion site and the patient's oral situation, in a perspective view. The male element 14, on the one hand, and the complete telescopic crown 30, i.e., the female element 18 mounted on the male element 14, are shown together in pairs. In particular, the following are shown:

[0105] FIG. 7a shows a male and female element 14, 18 with a non-round, oval or elliptical cross-section,

[0106] FIG. 7b a male and female element 14, 18 with trioval cross-section,

[0107] FIG. 7c a male and female element 14, 18 with quadoval cross-section,

[0108] FIG. 7d shows a male and female element 14, 18 with an elongated rectangular cross-section with rounded corners to meet the ovality criteria,

[0109] FIG. 7e a male and female element 14, 18 with a comparatively “flat”, elongated cross-section,

[0110] FIG. 7f shows the male and female elements 14, 18 according to FIG. 7e with an additional, partially circumferential undercut or groove 37 to provide additional retention.

[0111] The assembly of the matrix element 18 from the prefabricated components is shown in FIG. 8 using a sequence of assembly steps in partial section in a perspective view and in FIG. 9 using a sequence of assembly steps in longitudinal section. First, as shown in FIGS. 8a, 9a, the inner cap 32 is inserted into the intermediate body 36. At its free end 39, this has a circumferential end bead 40 which is inserted into a receiving groove 42 formed on the end of the inner cap 32. The resulting partially assembled assembly 44 is inserted into the outer cap 34, as can be seen in FIGS. 8b, 9b, so that the assembly 46 shown in FIGS. 8c, 9c is created. In this case, a circumferential fixing edge 48 formed in the end region of the inner cap 32 is inserted into a receiving ring 50 of the outer cap 34. Subsequently, a flanged edge 52 surrounding this is folded over to form a crimp or flanged connection, so that it is as shown in FIG.8d, 9d, it can be seen that it encloses the fixing edge 48 and thus sufficiently fixes the inner cap 32 to the outer cap 34 in the sense of pre-assembly. The matrix element 18 constructed and pre-assembled in this way is heated during insertion, as mentioned above, so that the thermoplastic intermediate body 36 is heated above its softening temperature and thus becomes deformable. In this state, insertion can then be carried out, so that the inner and outer caps 32, 34 are suitably aligned with one another according to the fine details of the oral situation and in response to the resulting pressure and positioning forces, with deformation of the intermediate body 36. As a result of this alignment, the inner cap 32, starting from the initially approximately parallel alignment as shown in Fig. 9d, is tilted or otherwise repositioned relative to the outer cap 34, whereby the intermediate body 36 is deformed accordingly.The result of such deformation, which accompanies the final alignment of the components, is shown by way of example in FIG. 10 using a longitudinal section of the die element 18 in the "tilted" state.

[0112] In comparison to the starting position (see FIG. 9d), the deformation of the intermediate element 36 that has occurred is clearly visible. It is equally evident, however, that the inner cap 32 is also significantly deformed in the region of the fixing edge 48 forming its base. According to an aspect considered to be independently inventive, this intended deformation of the inner cap 32 is taken into account by a suitable choice of material. The base region or fixing edge 48 of the inner cap 32, which forms a type of membrane, should offer no restoring force against this deformation, or only the smallest possible restoring force. This is achieved according to one aspect of the invention by a suitable choice of material for the inner cap 32, at least in the region of the fixing edge 48. The inner cap 32 is therefore preferably made of a high-performance plastic, preferably PEEK.

[0113] FIG. 11 shows an alternative embodiment of a matrix element 18' in longitudinal section. In this variant, the cover region 54 of the inner cap 32' is corrugated, allowing a certain degree of deformability, particularly in the longitudinal direction. Such a design thus allows for a certain degree of compensation or equalization of the positions of the components relative to one another in the longitudinal direction.

[0114] Taking these options into account, the dentist can pre-select the basic types provided in the library, and then determine which combination of patrice elements can minimize the overall need for grinding, i.e., the loss of tooth structure. The entire prosthesis can then be planned on this basis, and the dentist can be provided with the information required for grinding, which he can use to prepare the remaining teeth for crowning with the patrice elements 14. In order to enable the conceptually intended heating of the thermoplastic intermediate piece 36 of the telescopic crowns 30 to a temperature above the softening temperature immediately prior to insertion, a heating device 60 is provided according to one aspect of the invention, a section of which is shown in FIG. 12.The heating device 60 comprises a number of heatable contact plugs 62, the outer contour of which corresponds to the contour of the male elements 14 of the telescopic crowns 30 and can thus be inserted into the female elements 18 or their inner cap 32 instead of the male elements 14, and of which only one is shown in FIG. 12. The contact plugs 62 are therefore preferably designed to be as geometrically identical as possible to the actual male elements 14. According to one aspect of the invention, small grooves in the axial direction can be provided in the outer skin of the contact plugs 62 solely to facilitate removal of the heated female elements 18, so that no negative pressure can form during removal after heating. If the thermoplastic intermediate bodies 36 are heated, removal could result in damage to them if a negative pressure is present.

[0115] The contact plugs 62 can thus also be referred to as "heating patrices." For optimized heat dissipation, they are preferably made of a metal, preferably with high thermal conductivity, in particular gold. For heating, the respective matrix element 18 can then be plugged onto one of these contact plugs 62, and subsequently, by heating the contact plug 62, the thermoplastic intermediate body 36 of the matrix element 18 can be heated to a temperature above its softening temperature. The heating device 60 is equipped with one of the aforementioned heating elements or contact plugs 62 corresponding to the number of matrix elements 18 provided in the respective dental prosthesis 2 or the number of matrix elements 18 commonly used in such dental prostheses 2, preferably six, so that all matrix elements 18 of a dental prosthesis 2 can be heated simultaneously and thus prepared for insertion.

[0116] The possibility of inserting the contact plugs 62 into the inner cap 32 of a matrix element 18 is particularly clear from the various enlarged illustrations in Figures 13 to 17.

[0117] In the exemplary embodiment, the heatable contact plugs 62 are provided with an integrated heating element 64 with integrated temperature control. By applying a defined amount of heat energy over a defined period of time, the amount of heat required to soften the intermediate body 36 can be introduced into the intermediate body 36 or the thermoelastic layer, enabling the fine alignment of the inner cap 32 facing the male elements 14 relative to the outer cap 34 connected to the prosthesis 2. Furthermore, a handle 66 is preferably formed behind the actual heating male element 62 to allow the heating male elements 62 to be easily inserted into and removed from the female elements 18.

[0118] The heating elements 64, designed as internal electrical heaters, ensure that overheating and thus damage to the matrix-pattern system or the prosthesis 2 itself cannot occur. This control requires that temperature sensors 68 be integrated into the heating patrixes 62. Alternatively, the heating patrixes 62 could also be equipped with another heat source or be supplied via an external heat source. Furthermore, it is also possible for the heating patrixes 62 to simply heat the thermoelastic intermediate body 36 via another energy source without being heated themselves.

[0119] According to one aspect of the invention, a plurality of the heating male parts 62 are each connected via a cable connection 70 to a common, central temperature control unit (not shown in detail in FIG. 12). This unit preferably has four or six connections in order to be able to control four or six heating male parts 62 simultaneously. Alternatively, and depending on the intended use, such a unit could also be provided with a larger number of connections, for example 6, 8 or 10. According to one aspect of the invention, there should be at least as many as are usually provided with supporting pillars in a prosthesis 2. Preferably, the heating male parts 62 are directly provided with a cable connection 70, but are detachably connected to the central control unit via a plug.

[0120] In a particularly preferred embodiment, the heating elements 62 are equipped with rechargeable batteries that are located in a single charging station. The temperature control unit is integrated into the heating elements 62.

[0121] List of reference symbols

[0122] Telescopic system Dental prosthesis Upper jaw Tooth Telescopic crown Primary crown Male element Contact pin Female element Arrow Telescopic crown Inner cap Outer cap Intermediate body Groove Inner bead End bead Receiving groove , 46 Ensemble Fixing edge Receiving ring Beaded edge Lid area Heating device Contact plug Heating element Handle element Temperature sensors Cable connection

Claims

Claims Method for producing a dental prosthesis (2) which is provided with a number of matrix elements (18) corresponding to each of the matrix elements (14) for removable fixation to a number of teeth (6) in the mouth of a patient, each crowned with a male element (14), wherein the or each matrix element (18) is designed in several parts and comprises an inner cap (32) which can be plugged onto the associated male element (14) and an outer cap (34) attached to the dental prosthesis (2), and wherein in the space between the inner and outer caps (32, 34) there is arranged an intermediate body (36) made of thermoplastic material which connects them to one another, in which intermediate body (36) is heated to a temperature above its softening temperature and thus made deformable for the precise alignment of the inner cap (32) relative to the outer cap (34) of the respective matrix element (18),and then, utilizing the deformability of the intermediate body (36), the inner cap (32) is aligned relative to the outer cap (34) for optimized fit, taking into account intraoral data reflecting the actual dentition situation in the patient's oral cavity. The thus adjusted relative position of the inner cap (32) relative to the outer cap (34) is preserved as a result of the solidification of the intermediate body (36) that begins during the subsequent cooling of the intermediate body (36). A method for producing a dental prosthesis (2) which is provided with a number of matrix elements (18) corresponding to each of the matrix elements (14) for removable fixation to a number of teeth (6) in the mouth of a patient, each crowned with a male element (14), in particular using multi-part matrix elements (18).each comprising an inner cap (32) attachable to the associated male element (14) and an outer cap (34) attached to the dental prosthesis (2), wherein an intermediate body (36) made of thermoplastic material connecting the inner and outer caps (32, 34) is arranged in the space between the inner and outer caps, in particular according to claim 1, wherein, based on intraoral data reflecting the actual dentition situation in the patient's oral cavity, those male elements (14) are selected from a number of basic male element types stored in a component library that allow reliable fixation of the prosthesis (2) with the lowest possible removal of tooth hard substance, and wherein, based on this selection, the required grinding of the teeth (6) is determined and made available to the practitioner as an instruction manual.

Images