JPH0910233A - Production of tooth crown prosthetic appliance - Google Patents

Abstract

PURPOSE: To produce a crown prosthetic appliance adapted itself to a margin by numerically controlled machine tools. CONSTITUTION: A model processing section 8 forms the abutment tooth and ambient teeth consisting of a surface model from measurement data. A margin shape selecting means 9 extracts the margin line from a database 9A. A dental crown selecting means 10 compares the abutment tooth and the surface model of the tooth and crown shapes and selects the desired model. A deforming means 10A enlarges, reduces or rotates the selected model in compliance with the surface model. A margin adapted curved surface forming means 11 forms a curved surface part consisting of the surface between the max. built-up part of the deformed crown shape data and the margin line, forms the crown shape data meeting the margin line, prepares the blank for processing formed with the inner shape complied with the database 12A and calculates the margin position to the blank. The processing data are formed by a processing data forming means 13 and a processing means 3 is controlled, by which the crown prosthetic appliance is produced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a dental prosthesis by cutting NC.

[0002]

2. Description of the Related Art Crown prostheses such as crowns and bridges are manufactured by using the principle of the buried casting method. An impression of the abutment tooth inside and the surroundings and an opposing tooth is taken, and the occlusal state is recorded on an occlusal paper. Next, dental anhydrite is poured into the impression to make a working model with divided tooth molds. Next, draw a margin line on the abutment tooth of the plaster model. Next, a wax pattern is formed on the working model using an articulator and an articulating paper. In this case, make sure that the wax does not overflow from the margin line. Next, a sprue is provided and it is buried in a refractory material. Next, after burning the wax, the molten metal is filled into the space of the wax pattern shape through a sprue and cooled. The sprue is then removed and the surface is ground to give the desired prosthesis. By the way, the quality of this kind of prosthesis obtained by the above manufacturing method largely depends on the technical skills of the technicians involved in the manufacturing, and there are variations in quality due to differences in the technicians' skill levels, making it difficult to set quality standards. . In recent years, research on a method for manufacturing a dental prosthesis by using a three-dimensional system has been advanced, and by doing so, it is apt to ensure uniform quality by reducing the influence of the skill level of a technician or the like on the quality. A method of manufacturing a crown prosthesis using a three-dimensional system is to take an impression of an abutment tooth and its surroundings and an opposing tooth, inject dental anhydrite into the impression and harden it to form a working model. Then, the shape of this working model is measured by three-dimensional measurement technology and the treated tooth and surrounding data are stored in a computer, a three-dimensional model is created from that data, and this three-dimensional model is selected from the database. The created general prosthesis shape is overlaid, the general shape is transformed so as to match the shape and function required for reproduction, NC data of this transformed shape is created, and this NC data is created. There have been proposed various types such as those that manufacture a dental prosthesis by controlling an NC machine tool such as a milling machine. However, none of them considers the matching of the margin line between the abutment tooth and the crown prosthesis. In addition, when processing the inside and outside of the crown, it is necessary to change the direction of the work material, and it is difficult to position the work material.

[0003]

In the above-mentioned prior art, there is a problem that the fit of the margin line between the abutment tooth and the crown prosthesis is poor and the machining is difficult.

Therefore, an object of the present invention is to provide a method for manufacturing a crown prosthesis in which the margin line between the abutment tooth and the crown prosthesis is well fitted and which is easy to process.

[0005]

In order to solve the above-mentioned problems, a method for manufacturing a dental prosthesis according to the present invention selects desired dental crown shape data from a database based on measurement data,
In the method for producing a crown prosthesis by deforming and creating machining data based on this crown shape data and performing NC cutting processing by this machining data, the maximum crown height of the deformed crown shape data Part or a portion below the maximum tortuosity and shape data between a margin line selected from a database based on the measurement data or a margin line extracted from the measurement data is created, and a crown conforming to the margin line is created. Shape data is created, processing data is created from this crown shape data, and the processing material that pre-forms the inner crown shape corresponding to the margin line is set on the processing machine, and the tooth is processed by three-axis controlled cutting. The outer surface of the crown is processed.

According to the present invention, the crown shape data that matches the margin line of the abutment tooth is created, and the processing material is cut based on this crown shape data without changing the direction.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an embodiment of an apparatus configured for manufacturing a dental prosthesis, which is a three-dimensional CAD / CAM, a measuring means 2, a processing means 3 including a machine tool of three-axis control by NC, and a display 4. And input means 5. 3D CAD / CAM1 is a crown shape database 6
, Measurement data memory 7, model processing unit 8, margin database 9A, margin shape selecting means 9, margin deforming means 9B, tooth crown shape selecting means 10, tooth crown deforming means 10A, and margin fitting curved surface. Forming means 11;
It is composed of a material inner shape database 12A, a margin position calculating means 12 for the material, and a processing data creating means 13. The model processing unit 8 uses the three-dimensional coordinate value measurement data obtained by the measuring means 2 to determine the tooth defect site. A surface model serving as surrounding information is created, and the margin shape selecting means 9 selects a margin line having a shape most suitable for the abutment tooth shape of the surface model from the margin database 9A, and the margin deforming means 9B is selected. The margin line is enlarged or reduced according to the margin size of the abutment tooth. The crown shape selection means 10 compares and collates the defective portion and the surface model, which is the surrounding information, with the crown shape data in the crown shape database 6, and selects the desired crown shape data. The crown deforming means 10A deforms the selected crown shape data 16 so as to fit the surface model. The margin-adapted curved surface forming means 11 forms a surface between the maximum ridge portion or a lower portion of the deformed crown shape data and a selected / deformed margin line to form a crown-shaped surface conforming to the margin line. Create a model. The margin position calculation means 12 for the material reads out the material inner shape corresponding to the selected margin line from the material inner shape database 12A, and from the relationship between the material inner shape and the deformed margin line, the margin position for the processed material, that is, the Z position. Is calculated. The measuring means 2 is a measurement data memory 7
A suitable device capable of inputting measurement data such as an abutment tooth and its surroundings and a mating tooth can be used for Taking an impression of the surroundings and the opposing teeth, injecting dental anhydrite into the impression and hardening it to form a working model, and measuring the shape of this working model with a three-dimensional measuring machine and measuring data memory 7 To store. In this case, it is desirable that the measurement data be stored as data in which point sequence data is wireframed and smoothed. Similarly, when using a CT scan, the working model is also stored in the measurement data memory 7 as three-dimensional data measured by the conventional method. For example, various standard model models are created in the crown shape database 6, and the model is measured by the above-described three-dimensional measuring means to obtain three-dimensional coordinate value data. Based on this three-dimensional coordinate value data, three-dimensional CAD is performed. Shape data such as a surface model conventionally created using / CAM is stored, and various types of margin lines are stored as a wireframe in the margin database 9A. Then, there are prepared various kinds of processing materials in which the material inner shape is formed in advance in accordance with these many kinds of margin lines, and the material inner shape is stored in the material inner shape database 12A, and the margin line and the inner shape are stored. The processed material is registered with the corresponding management number. Further, the crown shape data and the margin line are used to distinguish front teeth, posterior teeth, upper and lower left and right teeth, first premolars, second premolars,
It is grouped and saved according to the type of tooth such as the first molar, the second molar, the third molar, etc. By inputting the tooth information, the desired group is read out and the data in the group are sequentially collated and searched. Has become. Further, as shown in FIG. 3, the crown shape data is created as a crown shape 16 from the cusp 14 to the lower edge 15 which is the maximum ridge. In the present embodiment, the operation is performed in an interactive manner with the display content of the display 4. For example, the manufacturing procedure of the crown is as follows: after treating a tooth as shown in FIGS. 6 and 9, the tooth is ground to form an abutment. An abutment tooth, a cavity-formed abutment tooth or a core-formed abutment tooth 17 is formed, and the abutment tooth 17 in the oral cavity and the teeth 18 and 19 around the abutment tooth 17 and paired teeth 20, 21, 22
Is measured by the measuring means 2 and input to the measurement data memory 7. Further, the tooth information of the defective portion, for example, the lower right first molar is input by the input means 5. Next, the model processing unit 8 creates a wire frame model from the measurement data, and creates an abutment tooth 17, teeth 18, 19, 20, 21, 21, which is a surface model, from this model.
Further, the margin shape selection means 9 selects the margin line 23 that best fits the margin portion of the abutment tooth 17 from the margin database 9A and deforms it by the margin deformation means 9B. As shown in FIGS. 6 and 9, the tooth crown selecting means 10A includes an abutment tooth 17, which is a surface model, and teeth 18, 19, and 2.
0, 21, 22 and the crown-shaped surface model 16 are compared and collated to select a desired model 16 as a prosthesis,
The deforming means 10 enlarges, reduces, or rotates the selected model according to the surface model. The margin conforming curved surface forming means 11 is shown in FIGS.
As shown in FIGS. 5, 8 and 11, the curved line portion 24 made of a surface is created between the maximum ridge portion 15 and the margin line 23 of the tooth crown shape data 16 transformed as shown in FIG. Shape data 16A that conforms to
Create The margin position calculation means 12 for the material reads the material inner shape corresponding to the selected margin from the database 12A, and deforms the margin line 2
From the Z position of the inner shape corresponding to 3, the Z position 25 for the material is calculated. The processing data creating means 13 creates processing data from the crown shape data 16A and the Z position 25, and controls the processing means 3 to manufacture a dental prosthesis. In this case, the margin conforming curved surface forming means 11 selects, for example, the margin line 23 and the maximum uplift portion 15 and executes the surface formation between them. Further, the amount of deformation by the deforming means 10A can be reduced by using the shape data registered in the crown shape database 10 as the shape data obtained by measuring the tooth of the patient before the loss. The shape data registered in the database 6 is shown in FIG.
As shown in FIG. 2, the lower edge 15 may extend below the maximum ridge. 13 to 16 show an example of processing. In this example, as shown in FIGS. 13 and 14, an inner shape hole 27 having a predetermined size and a slope is provided at the center of a processing material 26 forming a rectangular parallelepiped. The processing material 26 is set on a support base 28 made of synthetic resin formed by insert molding, for example. The processing materials prepared in advance are the same except that the inner shape differs according to the shape registered in the database 12A. Further, when the Z position is obtained by calculation, the diameter of each of the Z positions calculated based on the diameter of the truncated cone of the inner shape and the inclination of the peripheral surface is compared with the diameter of the margin.
Then, after the processing material 26 is set on the processing machine via the support base 28, the area above the parting is processed by the ball end mill 29 as shown in FIG. 15, and subsequently, as shown in FIG. The T cutter 30 processes up to the position. As described above, in the present embodiment, the crown shape data conforming to the margin can be formed based on the margin line obtained from the measurement data and the selected crown shape data. In addition to being easily manufactured, since the inner shape is formed in advance, the processing material can be processed relatively easily by a three-axis control processing machine without changing the direction.
17 and 18 show another embodiment of the present invention. When the same parts are designated by the same reference numerals and the description of the same parts is omitted, in this example, the margin database 9A is not provided and measurement is performed by the margin extracting means 9C. A margin line is extracted from the data to create a wireframe, and the inner material shape selecting means 12B compares and collates the margin line with the inner material shape of the database 12A to select a desired processing material, and further, a margin position for the material. The calculation unit 12 is configured to calculate the Z position, and has the same effect as the above embodiment. The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention. For example, as the shape data, the surface has been described, but it may be a solid or the like.
Further, the material of the support base may be appropriately selected. Further, the abutment tooth in the present invention means an abutment tooth having an abutment, an abutment tooth having a cavity, or an abutment tooth having a core.

[0008]

As described above, the present invention can provide a method capable of manufacturing a crown prosthesis which fits a margin by relatively simple processing.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart.

FIG. 3 is a schematic explanatory view showing tooth crown shape data.

FIG. 4 is a schematic explanatory view showing tooth crown shape data.

FIG. 5 is a schematic explanatory view showing tooth crown shape data.

FIG. 6 is a schematic explanatory diagram showing a state of creating tooth crown shape data.

FIG. 7 is a schematic explanatory view showing a state of creating tooth crown shape data.

FIG. 8 is a schematic explanatory view showing a state of creating tooth crown shape data.

FIG. 9 is a schematic explanatory diagram showing a state of creating tooth crown shape data.

FIG. 10 is a schematic explanatory view showing a state of creating tooth crown shape data.

FIG. 11 is a schematic explanatory view showing a state of creating tooth crown shape data.

FIG. 12 is a schematic explanatory view showing tooth crown shape data.

FIG. 13 is a schematic explanatory view showing a processing material and a support base.

FIG. 14 is a schematic explanatory view showing a processing material and a support base.

FIG. 15 is a schematic explanatory view showing a processed state.

FIG. 16 is a schematic explanatory view showing a processed state.

FIG. 17 is a block diagram showing another embodiment.

FIG. 18 is a flowchart showing another embodiment.

[Explanation of symbols]

 2 measuring means 3 processing means 6 crown shape database 9 margin shape selecting means 10 crown shape selecting means 11 margin conforming curved surface forming means 12 margin position calculating means for material

Claims (1)

[Claims] 1. A desired crown shape data is selected from a database based on measurement data and deformed, processing data is created based on this crown shape data, and NC cutting is performed by this processing data. In the method for producing a crown prosthesis by using the above, the maximum protuberance portion of the deformed crown shape data or a portion below the maximum protuberance portion and a margin line selected from a database based on the measurement data or extracted from the measurement data Creates shape data between the margin line and the margin line, creates crown shape data that fits the margin line, creates machining data from this crown shape data, and creates the inner crown shape corresponding to the margin line. A prosthesis for a dental crown, characterized in that a preformed work material is set in a processing machine, and the outer surface of the crown is processed by triaxial control cutting. Create method.