Method for manufacturing dental prostheses

Abstract

To provide a method of manufacturing a dental prosthesis and a manufacturing apparatus for manufacturing a dental prosthesis.SOLUTION: A method of manufacturing a dental prosthesis includes: step S101 of determining a first space area of a dental prosthesis that is exposed to a high load in comparison with a second space area of the dental prosthesis; and step S102 of manufacturing a dental prosthesis having a manufacturing material inside the first space area, the manufacturing material being different from that inside the second space area. The first space area is determined such that an internal pressure exceeding a given numerical value exists in the first space area.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] This invention relates to a method for manufacturing dental prostheses and a manufacturing apparatus for manufacturing dental prostheses.

Background Art

[0002] During the digital processing of crowns and bridges, the comprehensive load cases for those crowns and bridges are estimated. As a result, the number of bridge component units is restricted, or those components become oversized from the perspective of wall thickness. As a result, the mechanical properties of the materials used become several times that of the actual loads generated.

Summary of the Invention

Problems to be Solved by the Invention

[0003] An object of the present invention is to improve the processing of dental prostheses.

Means for Solving the Problems

[0004] The above problems are solved by the subject matter of the independent claims. Technically preferred embodiments are the subject matter of the dependent claims, the detailed description of the invention, and the accompanying drawings.

[0005] According to a first aspect, a step of determining a first spatial region of a dental prosthesis that is exposed to a higher load compared to a second spatial region of the dental prosthesis; and a step of manufacturing a dental prosthesis having a manufacturing material different from that in the second spatial region within the first spatial region. The technical problem is solved by a method for manufacturing a dental prosthesis. According to this method, the material properties can be utilized to the maximum extent, and the adaptation range can be expanded. By appropriate material adjustment, the pressure peak within the dental prosthesis can be absorbed. Therefore, this dental prosthesis can be manufactured with less material consumption.

[0006] According to a technically preferred embodiment of this method, the first spatial region is determined such that an internal pressure exceeding a given value exists within the first spatial region. This achieves the technical advantage of being able to determine the first spatial region in a simple manner, for example.

[0007] According to another technically preferred embodiment of this method, the load is calculated using the finite element method. This achieves the technical advantage of being able to calculate, for example, the load inside a dental prosthesis with high accuracy.

[0008] According to another technically preferred embodiment of this method, a given stress on the dental prosthesis is used in the finite element method. For example, calculations can be performed based on a worst-case scenario in which the expected maximum stress acts on the most unfavorable point of the dental prosthesis. This achieves the technical advantage of being able to calculate the dental prosthesis with high strength (biaxial strength, fracture resistance), for example.

[0009] According to another technically preferred embodiment of this method, the manufacturing material for the first and / or second spatial regions is selected based on the calculated load. This achieves the technical advantage of being able to adapt to the load by providing different strengths for each spatial region, for example.

[0010] According to another technically preferred embodiment of this method, the manufacturing material in the first spatial region is doped differently from that in the second spatial region. This achieves technical advantages such as enabling sintering without sintering delay and resulting in the manufacturing material having different strengths. In addition to sintering properties, mechanical properties, visual properties, and degradation resistance can also be tuned by doping.

[0011] The following values ​​are generally considered appropriate strength values ​​(flexural strength + fracture resistance) for zirconium dioxide with different yttrium doping:

[0012] Material 3Y-TZP 4Y-TZP 5Y-TZP

[0013] Biaxial bending: 1000±200(*), 750±100(*), 600±50(*) Strength [MPa]

[0014] Breakage durability 5.00±0.25 3.75±0.25 2.40±0.25 [MPa√m]

[0015] According to another technically preferred embodiment of this method, a manufacturing material having higher strength than that in the second spatial region is used in the first spatial region. This achieves the technical advantage of being able to reduce the wall thickness in the first spatial region, for example.

[0016] According to another technically preferred embodiment of this method, the manufacture of dental prostheses is carried out using a three-dimensional printing method. This achieves technical advantages such as the ability to efficiently manufacture dental prostheses.

[0017] According to another technically preferred embodiment of this method, the three-dimensional printing method uses free-jet material application. This achieves the technical advantage that, for example, the manufacturing material can be distributed to each spatial region in a simple manner.

[0018] According to the second embodiment, the technical problem is solved by a manufacturing apparatus for manufacturing a dental prosthesis, comprising: a determination device for determining a first spatial region of a dental prosthesis that is exposed to a higher load than a second spatial region of the dental prosthesis; and a manufacturing device for manufacturing a dental prosthesis having a different manufacturing material in the first spatial region than in the second spatial region. This manufacturing apparatus achieves the same technical advantages as the method according to the first embodiment.

[0019] According to a technically preferred embodiment of this manufacturing apparatus, the determination device is configured to determine the first spatial region such that an internal pressure exceeding a given value exists within the first spatial region. This achieves the technical advantage of being able to determine the first spatial region in a simple manner, for example.

[0020] According to another technically preferred embodiment of this manufacturing apparatus, the determination device is configured to calculate the load using the finite element method. Thereby, for example, a technical advantage of being able to calculate the load with high accuracy is achieved.

[0021] According to another technically preferred embodiment of this manufacturing apparatus, the manufacturing equipment is configured to select the manufacturing material for the first and / or second spatial regions based on the calculated load. Thereby, for example, a technical advantage of simplifying the manufacturing of dental prostheses is also achieved.

[0022] According to another technically preferred embodiment of this manufacturing apparatus, the manufacturing equipment is configured such that the manufacturing material in the first spatial region is doped differently from that in the second spatial region. Thereby, for example, a technical advantage of being able to perform sintering without sintering delay is also achieved.

[0023] According to another technically preferred embodiment of this manufacturing apparatus, the manufacturing equipment includes a three-dimensional printer. Thereby, for example, a technical advantage of being able to efficiently perform the manufacturing of dental prostheses is also achieved.

[0024] Examples of the present invention are shown in the accompanying drawings and will be described in detail below.

Brief Description of the Drawings

[0025] [Figure 1] It is a schematic explanatory diagram showing the manufacturing of a dental prosthesis. [Figure 2] It is a schematic explanatory diagram showing a manufacturing apparatus for manufacturing a dental prosthesis. [Figure 3] It is a block diagram of a method for manufacturing a dental prosthesis.

Embodiments for Carrying Out the Invention

[0026] Figure 1 schematically illustrates the manufacturing process of a dental prosthesis 100. The dental prosthesis 100 may be, for example, a crown, bridge, partial or complete denture.

[0027] To more effectively utilize the mechanical properties of the manufacturing materials 107-1 and 107-2, a given load case on the dental prosthesis 100 is first simulated using FEM software (finite element method software). To determine weak points within the dental prosthesis 100, the FEM software can calculate internal stress changes and pressures based on a three-dimensional model of the dental prosthesis 100. To easily recognize spatial regions (sub-volumes) with excessive and insufficient loads, these regions can be characterized with special coloring. This method allows, for example, the identification of spatial regions 101-1 within the dental prosthesis 100 where the internal pressure exceeds a given value.

[0028] Therefore, the dental prosthesis 100 can be subjected to loads caused by specific stresses that may occur during its use. These stresses act on vulnerable points of the dental prosthesis 100. For example, if the dental prosthesis 100 is a bridge, the maximum stress is applied to the center of the bridge. In this case, the FEM software calculates how the pressure is distributed within the bridge. This method allows for the identification of spatial regions 101-1 where the pressure is particularly high.

[0029] However, it is also possible to measure the actual stresses that occur based on the actual occlusal conditions using a pressure sensing mat. The pressure sensing mat measures the stresses that occur when teeth occlude. The detected stresses can then be used by FEM software for the dental prosthesis 100 to calculate the pressure distribution inside the dental prosthesis 100 under actual conditions.

[0030] In addition, because the FEM software recognizes the mechanical properties of the different manufacturing materials 107-1 and 107-2 available, it can provide material adjustment suggestions. Since the FEM analysis within the dental prosthesis 100 reveals under- and / or over-judged spatial areas 101-1 and 101-2, appropriate corrective actions can be performed. This minimizes the probability of component failure and allows for load-bearing compensation to be provided to the customer. Furthermore, the software enables validation of the manufacturing materials 107-1 and 107-2 used.

[0031] Figure 2 shows an overview of a manufacturing apparatus 200 for manufacturing a dental prosthesis 100. The manufacturing apparatus 200 includes a determination device 103 that determines which of the first spatial regions 101-1 of the dental prosthesis 100 is subjected to a higher load than the second spatial region 101-2 of the dental prosthesis 100.

[0032] The determination device 103 includes, for example, a processor and memory, within which FEM software is executed. The determination device 103 is configured, for example, by a computer.

[0033] The FEM software operating on the determination device 103 calculates spatial regions that experience higher mechanical loads compared to other spatial regions, according to the digital model of the dental prosthesis 100. This method allows the digital model of the dental prosthesis 100 to be divided into different spatial regions 101-1 and 101-2. In this case, three or more spatial regions with different mechanical loads can be identified within the dental prosthesis 100. A unique manufacturing material can be used for each of these spatial regions.

[0034] Subsequently, the determination device 103 transmits control data to the manufacturing equipment 105 that manufactures the dental prosthesis 100. The determination device 103 can automatically assign manufacturing materials 107-1 and 107-2 to be used for different spatial regions 101-1 and 101-2, respectively, according to the calculated load. This is possible because the determination device 103 is aware of the available manufacturing materials.

[0035] The manufacturing equipment 105 uses a different manufacturing material 107-1 in the first spatial region 101-1 than in the second spatial region 101-2. This manufacturing material 107-1 can have higher strength compared to the other manufacturing material 107-2.

[0036] The manufacturing equipment 105 uses additive manufacturing processes such as polyjet 3D printing and multijet 3D printing, in which, for example, droplet-shaped raw materials are selectively applied in layers. The manufacturing equipment 105 includes, for example, a first container 109-1 for a first manufacturing material 107-1 and a second container 109-2 for a second manufacturing material 107-2. A control signal from the determination device operates the manufacturing equipment 105 to automatically use the manufacturing material 107-1 or 107-2 that is assigned to each spatial region 101-1 and 101-2 when printing.

[0037] The manufacturing apparatus 200 can reduce the isotropy of the load distribution inside the dental prosthesis 100. For spatial regions 101-1 where stronger performance is required or where a stronger load is applied, a different, for example, harder manufacturing material 107-1 can be used, for example, zirconium oxide with 3 wt% yttrium oxide (3YTZP) can be used instead of zirconium oxide with 5 wt% yttrium oxide (5YTZP).

[0038] If the same manufacturing material 107 were used for both spatial regions 101-1 and 101-2, this would necessitate an increase in the thickness of the dental prosthesis 100, which is often disadvantageous for aesthetic and tactile reasons. The manufacturing apparatus 200 allows for a reduction in wall thickness for good aesthetics when there is little load on the sub-volume.

[0039] This selective adjustment of material allocation can be performed within the framework of additive multi-material processing, in which case selective material application can be freely performed in three-dimensional space, for example, as free-jet material application in polyjet or multi-jet 3D printing.

[0040] In the case of three-dimensional inkjet printing, manufacturing materials 107-1 and 107-2 having a viscosity of, for example, more than 15 mPas, preferably more than 150 mPas, and most preferably more than 200 mPas, can be jet-sprayed at an appropriate processing temperature. By selective material application via material jet spraying, extremely small spatial regions 101-1, with a size of as little as one voxel, can be constructed using different manufacturing materials 107-1 and 107-2.

[0041] If the design of the dental prosthesis 100 is changed by the user, or if different manufacturing materials 107-1 and 107-2 with different mechanical properties are assigned, the changes can be made visible to the user. If the design and manufacturing materials 107-1 and 107-2 are appropriate, the user can begin printing the dental prosthesis 100. The dental prosthesis is automatically constructed within the corresponding spatial areas 101-1 and 101-2 using the appropriate manufacturing materials 107-1 and 107-2.

[0042] Figure 3 shows a block diagram of a method for manufacturing a dental prosthesis 100. In step S101, the first spatial region 101-1 of the dental prosthesis 100 is determined to be subjected to a higher load than the second spatial region 101-2 of the dental prosthesis 100. In step S102, the dental prosthesis 100 is manufactured using a different manufacturing material 107-1 in the first spatial region 101-1 than in the second spatial region 101-2. This method can be applied to all spatial regions 101-1 and 101-2 of the dental prosthesis 100.

[0043] During the processing of zirconium oxide slurry, the firing properties within a spatial region can be locally altered by selectively doping different material layers at the green body stage. This leads to different strength regions in the final dental prosthesis 100 in firing processes using different manufacturing materials 107-1 and 107-2. Selective doping is performed, for example, by jetting a penetrating solution onto a previously applied and dried material layer. In addition to firing properties, mechanical properties, optical properties, and degradation resistance can also be adjusted by doping.

[0044] This method allows for the detection of spatial areas 101 within the dental prosthesis 100 that have been identified as highly important or need reinforcement. Accordingly, different manufacturing materials 107-1 and 107-2 with different mechanical properties can be selectively and locally assigned. This allows for the adaptation of the final crown or bridge, consisting of the manufacturing materials 107-1 and 107-2 (composite or ceramic), to individual loading conditions.

[0045] The range of applicability can be expanded, and the resulting load can be quantified and visualized. When fabricating dental prostheses, dental technicians can be assisted by displaying the spatial region 101 where the wall thickness can be reduced or increased. By assigning different manufacturing materials 107-1 and 107-2 with different mechanical properties to the corresponding spatial region 101, peak loads can be absorbed without additionally increasing the wall thickness.

[0046] All features described and illustrated in relation to individual embodiments of the present invention can be applied to the present invention in various combinations, thereby achieving effective advantages simultaneously.

[0047] All method steps can be performed using apparatus suitable for carrying out each method step. All functions performed by the feature in question can be method steps in this method.

[0048] The scope of protection of this invention is defined by the appended claims and is not limited by the features described or illustrated in this description. [Explanation of symbols]

[0049] 100 Dental prostheses 101 Spatial domain 103 Judgment device 105 Manufacturing equipment 107 Manufacturing materials 109 Container

Claims

1. A method for manufacturing a dental prosthesis (100) comprising: step (S101) determining a first spatial region (101-1) of a dental prosthesis (100) that is subjected to a higher load than a second spatial region (101-2) of the dental prosthesis (100); and step (S102) manufacturing a dental prosthesis (100) having a manufacturing material (107-1) in the first spatial region (101-1) that is doped differently from that in the second spatial region (101-2), wherein the manufacturing material is doped differently in the first spatial region and the second spatial region by injecting a permeable fluid.

2. The method according to claim 1, wherein the first spatial region (101-1) is determined such that an internal pressure exceeding a given value exists within the first spatial region (101-1).

3. The method according to claim 2, which calculates the load using the finite element method.

4. The method according to claim 3, wherein a given stress applied to a dental prosthesis (100) is used in the finite element method.

5. The method according to claim 1, wherein a manufacturing material (107-1, 107-2) for a first and / or second spatial region (101-1, 101-2) is selected based on a calculated load.

6. The method according to claim 1, wherein a manufacturing material (107-1) having higher strength than that in the second spatial region is used in the first spatial region (101-1).

7. The method according to claim 1, wherein the manufacture of a dental prosthesis (100) is carried out using a three-dimensional printing method.

8. The method according to claim 7, wherein the three-dimensional printing method uses a free-jet material application method.

9. A determination device (103) for determining a first spatial region (101-1) of a dental prosthesis (100) that is subjected to a higher load than a second spatial region (101-2) of the dental prosthesis (100), and a manufacturing device (105) for manufacturing a dental prosthesis (100) having a different manufacturing material (107-1) in the first spatial region (101-1) than in the second spatial region (101-2), wherein the manufacturing material is doped differently in the first spatial region and the second spatial region by injecting a permeable fluid, and the device (200) for manufacturing a dental prosthesis (100).

10. The manufacturing apparatus (200) according to claim 9, wherein the determination device (103) is configured to determine the first spatial region (101-1) such that an internal pressure exceeding a given value exists within the first spatial region (101-1).

11. The manufacturing apparatus (200) according to claim 10, wherein the determination device (103) is configured to calculate the load using the finite element method.

12. The manufacturing apparatus (200) according to claim 10, wherein the manufacturing equipment (105) is configured to select manufacturing materials (107-1, 107-2) for a first and / or second spatial region (101-1, 101-2) based on a calculated load.

13. The manufacturing apparatus (200) according to claim 10, wherein the manufacturing equipment (105) is configured such that a different doping is applied to the manufacturing material (107-1) in the first spatial region (101-1) than in the second spatial region (101-2).

14. The manufacturing apparatus (200) according to claim 10, wherein the manufacturing equipment (105) includes a three-dimensional printer.

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