JP2015136520A - Method for fabricating plate denture, design support device of plate denture and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for fabricating a plate denture in which the tissue conditioning of an occlusal surface is automated.SOLUTION: A three dimensional model of a plate denture is constructed which contains a denture base and a plurality of artificial teeth arranged on the denture base. First NC data for fabricating the denture base is generated by using an NC machine tool, based on the three dimensional model of the plate denture. A tilt angle to be imparted in each occlusal facet of the artificial teeth of at least a part of the plurality of artificial teeth is derived, based on the tilt of a plane containing fixed points of the plurality of artificial teeth specified by the three dimensional model of the plate denture. Second NC data is generated for forming the occlusal facet having the tilt angle derived in the third step by using the NC machine tool in at least part of the artificial teeth. The denture base is fabricated by using the NC machine tool with the first NC data entered therein. The plurality of artificial teeth are fixed to the fabricated denture base. The occlusal facet having the tilt angle is formed in the at least part of the artificial teeth by using the NC machine tool with the second NC data entered therein.

Description

  The present invention relates to a method for manufacturing a denture, a design support device for a denture, and a program.

  Conventionally, most of restorations and prostheses (inlays, partially covered crowns, fully covered crowns, bridges, partially dentures, fully dentures, implant superstructures, etc.) that are installed in the oral cavity during dental treatment, It has been produced by hand. In recent years, denture manufacturing using a CAD / CAM (Computer Aided Design and Computer Aided Manufacturing) system has been proposed. A dental CAD / CAM system is a series of systems that replaces part of the manufacturing process, including the design and processing of restorations and prostheses, with computer-controlled equipment. Introducing a CAD / CAM system in the manufacture of a denture has advantages that work efficiency can be improved and variation in quality can be suppressed.

  For example, Patent Document 1 discloses a technique related to a method for manufacturing a plate denture using a CAD / CAM system. Patent Document 1 describes a method for producing a plate denture including the following steps. (1) Step of photographing an old denture and obtaining imaging data of the old denture (2) Displaying a three-dimensional image of the old denture based on the imaging data of the old denture, and an artificial tooth based on the data of only the artificial tooth The step of displaying the three-dimensional image of the new denture based on the three-dimensional image of the new denture displayed by the three-dimensional image of the old denture and the three-dimensional image of the artificial tooth (3) A step of removing artificial teeth from the new denture in the displayed three-dimensional image of the new denture and acquiring three-dimensional shape information of the denture base of the new denture based on the displayed three-dimensional image of the denture base of the new denture (4) A step of forming a resin on a denture base having a predetermined shape based on the three-dimensional shape information of the denture base of the new denture (5) a step of adhering the artificial tooth to the concave portion for the artificial tooth arrangement formed on the surface of the denture base.

International Publication No. 2010/058822 Pamphlet

  In conventional denture manufacturing without using a CAD / CAM system, commercially available artificial teeth are arranged on a denture base mounted on an articulator. In this case, in order to obtain a more reliable cusp fitting position and to obtain a more anatomical, functional, and physiological occlusal surface form, it is essential to correct the form of the occlusal surface after the artificial tooth arrangement. The occlusal surface shape correction is usually repeated so that an ideal occlusal contact can be obtained while carbon paper is interposed between the upper and lower occlusal surfaces and the occlusal surfaces are rubbed together and the portion where the carbon ink is adhered is well observed. This is an important task in order to ensure smooth jaw movement and denture stability when the denture is placed in the oral cavity, so that there is no cusp interference during forward and lateral movement of the lower jaw. is there.

  Thus, in conventional denture manufacturing without using a CAD / CAM system, diamond or carborundum is used so that the occlusal surface of the upper and lower jaw artificial teeth is in an appropriate form after the artificial teeth are fixed to the denture base. It is common to perform form correction manually using the provided cutting equipment, and such work is essential. The reason why such a work is necessary is that the form of the occlusal surface of the ready-made artificial tooth is only an average form, and it only serves as a platform.

  On the other hand, in recent denture manufacture using a CAD / CAM system, an artificial tooth is fixed to a denture base manufactured using an NC machine tool using an adhesive or the like, and then the artificial tooth according to the thickness of the adhesive is used. In order to correct the floating amount and obtain a more ideal occlusal surface form, the occlusal surface form is corrected. As described above, even when using a CAD / CAM system, in order to provide a higher-quality denture to a customer, it is essential to modify the shape of the occlusal surface as long as a commercially available artificial tooth is used. It was necessary to attach the fixed denture to the articulator once. However, such manual modification of the occlusal surface is a complicated and trial-and-error and cumbersome task, and lacks a viewpoint for productivity.

  The present invention has been made in view of the above points, and an object of the present invention is to automate the occlusal surface shape correction in the manufacture of a denture.

  According to the first aspect of the present invention, a first step of constructing a three-dimensional model of a denture including a denture base and a plurality of artificial teeth arranged on the denture base, and the tertiary of the denture base Based on the original model, a second step of generating first NC data for manufacturing the denture base using an NC machine tool, and the plurality of artificial prostheses specified from the three-dimensional model of the denture A third step of deriving an inclination angle to be applied to each occlusal facet of at least some of the artificial teeth based on an inclination of a plane including a predetermined point of the teeth, and using an NC machine tool A fourth step of generating second NC data for forming an occlusal facet having an inclination angle derived in the third step on the at least some artificial teeth, A manufacturing method is provided.

  According to a second aspect of the present invention, a fifth step of manufacturing the denture base using an NC machine tool to which the first NC data is input, and the denture manufactured in the fifth step A sixth step of fixing the plurality of artificial teeth to the floor, and forming an occlusal facet having the inclination angle on the at least some artificial teeth using an NC machine tool to which the second NC data is input. A manufacturing method according to the first aspect, further comprising: a seventh step.

  According to a third aspect of the present invention, in the third step, the inclination angle is derived by substituting a numerical value corresponding to the inclination of the adjustment curved plane into a predetermined mathematical expression corresponding to each occlusal facet. A manufacturing method according to the first or second aspect is provided.

  According to a fourth aspect of the present invention, the process in the sixth step is performed inside the NC machine tool used in the fifth step, and the process in the seventh step is performed in the fifth process. A manufacturing method according to the second aspect performed using the used NC machine tool is provided.

  According to a fifth aspect of the present invention, after the completion of the fifth step, the denture base is taken out from the NC machine tool used in the fifth step, and the processing in the sixth step is performed. The manufacturing method by the 2nd viewpoint which performs the process in the said 7th process by installing the said denture base in the original position of the NC machine tool used in the said 5th process after completion of this process is provided.

  According to a sixth aspect of the present invention, each of the plurality of artificial teeth is a manufacturing method according to any one of the first to fifth aspects, wherein at least one of the occlusal surface form and the polished surface form is non-anatomical. Is provided.

  According to a seventh aspect of the present invention, the molar prosthetic tooth among the plurality of artificial teeth is occluded by the occlusal surface being closed by a plane including all the cusps on the proximal distal side and the buccal tongue side. A manufacturing method according to a sixth aspect in which the surface has a planar shape is provided.

  According to an eighth aspect of the present invention, a plane including predetermined points of the plurality of artificial teeth based on a three-dimensional model of a denture including a denture base and a plurality of artificial teeth arranged on the denture base. A process for deriving a numerical value corresponding to an inclination, a process for deriving an inclination angle to be given to each occlusal facet of at least some of the artificial teeth by substituting the numerical value into a predetermined mathematical formula, A program for causing a computer to execute is provided.

  According to a ninth aspect of the present invention, a plane including predetermined points of the plurality of artificial teeth based on a three-dimensional model of a denture having a denture base and a plurality of artificial teeth arranged on the denture base. First deriving means for deriving a numerical value corresponding to the inclination; and deriving an inclination angle to be given to each occlusal facet of at least some of the artificial teeth by substituting the numerical value into a predetermined mathematical formula And a second support means for providing a denture design support device.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to automate the occlusal surface form correction in manufacture of a plate denture.

It is a block diagram which shows an example of the hardware constitutions of the CAD / CAM system used for manufacture of the denture based on embodiment of this invention. It is a manufacturing process flowchart which shows an example of the manufacturing method of the denture based on embodiment of this invention. (A) is the external view seen from the mucous membrane surface side of the denture base manufactured by cutting, (B) is the external view seen from the grinding | polishing surface side. It is an external view of a floor denture (the lower jaw part of all upper and lower jaw dentures). It is a figure which shows a mode that NC machine tool is performing the form correction of the occlusal surface of the artificial tooth of a base denture. It is a flowchart which shows the flow of the process in the inclination angle derivation processing program which concerns on embodiment of this invention. It is a top view which shows an adjustment curve plane. It is a figure which shows an example of a structure of the occlusal facet formed in a molar part artificial tooth. It is a flowchart which shows the method of deriving the regression type which concerns on embodiment of this invention. It is a figure which shows the combination of the adjustment curvature angle of the some denture manufactured in order to derive the regression type which concerns on embodiment of this invention. It is a figure which shows the structure of the database which concerns on embodiment of this invention. (A) is a figure which shows the external appearance of the flat artificial tooth (molar part artificial tooth) whose occlusal surface is incomplete. (B) is a figure which shows the external appearance of the flat artificial tooth (front-tooth part artificial tooth) whose cutting edge form is incomplete.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing an example of a hardware configuration of a CAD / CAM system 100 used for manufacturing a denture according to an embodiment of the present invention. The CAD / CAM system 100 is an example of a design support apparatus according to the present invention.

  The CAD / CAM system 100 is configured by a computer including an arithmetic processing device 110, a main storage device 111, an input device 112, an output device 113, an auxiliary storage device 114, and an interface device 115 that are connected to each other via a bus 120. Yes.

  The arithmetic processing unit 110 controls the entire CAD / CAM system 100 and executes the CAD program 200 and the CAM program 210 stored in the auxiliary storage device 114. The main storage device 111 has a storage area for temporarily storing a program and data being executed, and is configured by, for example, a RAM (Random Access Memory). For example, the input device 112 includes a keyboard, a mouse, a tablet, and the like. For example, the output device 113 includes a display, a printer, and the like.

  The auxiliary storage device 114 is a non-volatile storage device such as a hard disk device, for example, and a CAD program 200, a CAM program 210, mathematical formula data 220 described later, and the like are stored in the auxiliary storage device 114. In addition, when the CAD program 200 and the CAM program 210 are provided by a portable recording medium such as a CD-ROM or provided via a network, these programs are supported via the interface device 115. It can be installed in the storage device 114. As the CAD program 200, a commercially available CAD program can be used. As the CAM program 210, a commercially available CAM program can be used.

  The user can perform a floor denture design work on the CAD / CAM system 100 by operating the input device 112 while checking the model output to the output device 113.

  Below, the manufacturing method of the denture using the CAD / CAM system 100 which concerns on embodiment of this invention is demonstrated. FIG. 2 is a manufacturing process flow chart showing an example of a method for manufacturing a denture according to an embodiment of the present invention.

  First, the upper tray and the lower tray holding the impression material are inserted into the oral cavity of the patient, the patient's upper and lower jaws are taken, and then the occlusal is taken by the usual method (step S1).

  Next, the shape and jaw position of the impression material held on the upper and lower trays taken out from the patient's oral cavity are scanned with, for example, an optical scanner to obtain three-dimensional data of the maxillary and mandibular ridge shapes (Step S2).

  Next, three-dimensional data of the artificial tooth shape is acquired by scanning the shape of the ready-made artificial tooth used for the denture, for example, with an optical scanner or the like (step S3). In addition, this process S3 can be abbreviate | omitted when the three-dimensional data of artificial tooth shape are already acquired, or when it can obtain from the outside.

  Next, the three-dimensional data of the jaw ridge shape acquired in step S2 and the three-dimensional data of the artificial tooth shape acquired in step S3 are taken into the CAD / CAM system 100. The three-dimensional data of the ridge shape and the three-dimensional data of the artificial tooth shape are stored in the auxiliary storage device 114 of the CAD / CAM system 100 (step S4).

  Next, using the CAD / CAM system 100, a denture is designed. Based on the three-dimensional data of the ridge shape stored in the auxiliary storage device 114, the arithmetic processing device 110 displays the three-dimensional model of the ridge shape (hereinafter referred to as a virtual ridge shape) on the display constituting the output device 113. Display). The user arranges a three-dimensional model of an artificial tooth shape (hereinafter referred to as a virtual artificial tooth) so that the occlusal surface fits in a maximum area on the virtual jaw ridge displayed on the display. In addition, in order to ensure the cutting margin by grinding after artificial tooth arrangement, about 0.5 mm at the second molar equivalent part, about 1.0 mm at the first premolar equivalent part, in the Z-axis direction (vertical direction) It is preferable to raise the occlusal height and arrange virtual artificial teeth. Then, a gingival part is provided to complete a three-dimensional model of a bed denture (step S5).

  Next, using the CAD / CAM system 100, based on the three-dimensional model of the denture constructed in step S5, an inclination angle to be given to each occlusal facet formed on each molar artificial tooth is determined. Derived (step S6). That is, in this step, the inclination angle of each occlusal facet suitable for the patient is derived by a calculation process by the CAD / CAM system 100. Details of this step will be described later.

  Next, the CAD / CAM system 100 is used to construct a three-dimensional model of the denture base by deleting the virtual artificial tooth portion from the three-dimensional model of the base denture generated in step S5 by a set operation (boolean operation). (Step S7).

  Next, the CAD / CAM system 100 is used to generate NC data for denture base operation (hereinafter also referred to as first NC data). In other words, in this step, the arithmetic processing unit 110 executes the CAM program 210 and, based on the constructed denture base three-dimensional model, generates NC data for causing the NC machine tool to manufacture a denture base. Data is generated (step S8). The NC data is data for instructing the NC machine tool such as the type and shape of the tool, the machining site, the machining conditions, the machining start and end points, the tool movement (tool path), and the like.

  Next, using the CAD / CAM system 100, NC data for correcting the shape of the artificial occlusal surface (hereinafter also referred to as second NC data) is generated. That is, in this process, the arithmetic processing unit 110 executes the CAM program 210 and uses the NC data for causing the NC machine tool to form the occlusal facet having the inclination angle derived in step S6 as the second NC data. Generate (step S9).

  Next, the first NC data generated in step S8 is input to the NC machine tool. The NC machine tool cuts a resin block, which is a material for the denture base, based on the first NC data, and forms a fixing hole for fixing the mucosa surface, the polished surface, and the artificial tooth of the denture base. As the NC machine tool, a commercially available NC machine tool can be used (step S10). Here, FIG. 3 (A) is an external view of the denture base 10 manufactured by cutting the resin block 10A as viewed from the mucosal surface side, and FIG. 3 (B) is an external view as viewed from the polished surface side. It is.

  Next, with the denture base manufactured in step S10 held on the stage of the NC machine tool, an artificial tooth is inserted into the fixing hole of the denture base and fixed using an adhesive or the like (step S11). FIG. 4 is an external view of a plate denture 30 (the lower jaw portion of the upper and lower jaw full denture) manufactured by fixing the artificial tooth 20 to the denture base 10.

  Next, the second NC data generated in step S9 is input to the NC machine tool. Based on the second NC data, the NC machine tool performs grinding of the artificial tooth of the plate denture that is held on the stage. Thus, an occlusal facet having an inclination angle derived by arithmetic processing (that is, an inclination angle suitable for the patient) is formed on each molar artificial tooth, and the shape of the artificial occlusal face is corrected ( Step S12). FIG. 5 is a diagram illustrating a state in which the NC machine tool 40 corrects the shape of the occlusal surface of the artificial tooth 20 of the bedded denture 30.

  Thereafter, the denture is completed by performing surface processing or the like for preventing the adhesion of dirt as necessary.

  In the present embodiment, the workpiece is held on the stage of the NC machine tool until the denture base is cut (step S10) until the occlusal surface shape correction (step S12) is completed. However, when performing the step S11 of fixing the artificial tooth in the fixing hole of the denture base, the work may be once taken out from the NC machine tool. In this case, after the fixation of the artificial teeth is completed, the workpiece is re-installed at the origin before the workpiece is taken out of the NC machine tool, and the occlusal surface shape is corrected (step S12). At this time, a repositioning and fixing device that can re-install the workpiece at the origin before the workpiece is taken out of the NC machine tool may be used.

  Hereinafter, in the above-described step S6, a process in which the CAD / CAM system 100 derives an inclination angle to be applied to each occlusal facet formed on each molar artificial tooth will be described.

  FIG. 6 is a flowchart showing the flow of processing in the tilt angle derivation processing program executed by the arithmetic processing unit 110 in step S6. The program may be configured as a part of the CAD program 200 stored in the auxiliary storage device 114.

  In step S <b> 21, the arithmetic processing unit 110 identifies the adjustment curved plane R from the three-dimensional model of the denture generated in step S <b> 5. For example, as shown in FIG. 7, the adjustment curved plane R includes the mandibular first premolar buccal cusp Q1, the mandibular second molar distal buccal cusp Q2, and the mandibular second molar distal lingual bite. It can be a plane including the top Q3. The arithmetic processing unit 110 specifies the adjustment curved plane R for each of the right side and the left side from the three-dimensional model of the denture. The arithmetic processing unit 110 may specify the adjustment curved plane R by designating points corresponding to Q1, Q2, and Q3 on the CAD. Further, in this step, it is only necessary to specify an index indicating the characteristic of the adjustment curve unique to the patient, and a plane including points other than the above-described Q1, Q2, and Q3 may be specified as the adjustment curve plane R.

In step S22, the arithmetic processing unit 110 derives the sagittal adjustment curve angle θ _S and the side adjustment curve angle θ _H from the adjustment curve plane R specified in step S21. The sagittal adjustment curve angle is a sagittal plane projection angle formed by the adjustment curve plane R and the virtual occlusal plane. On the other hand, the lateral adjustment curve angle is a frontal projection angle formed by the adjustment curve plane R and the virtual occlusal plane. Note that the virtual occlusal plane is an occlusal plane that serves as a reference for arranging artificial teeth when all dentures are manufactured. The sagittal plane is a plane that divides the human body into left and right. The frontal surface is a surface that divides the human body into the ventral side and the dorsal side. The arithmetic processing unit 110 derives the sagittal adjustment curve angle θ _S and the side adjustment curve angle θ _H for each of the right side and the left side.

In step S23, for example, the arithmetic processing unit 110 reads a mathematical formula represented by the following formula (1) from the auxiliary storage device 114, and calculates the sagittal adjustment bending angle θ _S and the lateral direction derived in step S22 to the mathematical formula. by substituting the value of the adjustment bending angle theta _H, it derives an inclination angle phi _i to be applied to the occlusal facets P _i.
φ _i = a _i θ _S + b _i θ _H + c _i (1)
The above mathematical formula is stored in advance in the auxiliary storage device 114 as mathematical formula data 220 (see FIG. 1). (1), based on the inclination angle of each occlusal facet recorded in the database, which will be described later, the inclination angle phi _i occlusal facets P _i intended variables, sagittal adjust the bending angle theta _S and side regulation It is a regression equation derived by performing regression analysis using a linear model with the bending angle θ _H as an explanatory variable. In equation (1), a _i and b _i are partial regression coefficients corresponding to the occlusal facet P _i , and c _i is a constant term corresponding to the occlusal facet P _i . The occlusal facet is a surface that forms a plurality of artificial tooth occlusal surfaces formed on each of the molar artificial teeth.

  FIG. 8 is a diagram illustrating an example of the configuration of the occlusal facet P formed on the molar artificial tooth. In FIG. 8, an occlusal facet P is formed in each of the regions surrounded by a broken line. Specifically, the left and right maxillary second molars 21 each have seven occlusal facets, and the left and right maxillary first molars 22 each have ten occlusal facets. The left and right maxillary second premolar teeth 23 each have five occlusal facets, and the left and right maxillary first premolar teeth 24 have four occlusal facets. That is, a total of 52 occlusal facets are formed on the plurality of molar prosthetic teeth arranged in the upper jaw.

  The left and right lower second molars 25 have 10 occlusal faces, and the left and lower lower first molars 26 have 10 occlusal faces. The left and right lower second premolars 27 each have five occlusal facets, and the left and lower lower first bicuspid teeth 28 each have two occlusal faces. That is, a total of 54 occlusal facets are formed on the plurality of artificial molars arranged in the lower jaw.

In this way, a total of 106 occlusal facets are formed for the upper and lower molars. The regression equation represented by the equation (1) is separately determined for each of the 106 occlusal facets, and is stored in advance in the auxiliary storage device 114 as the equation data 220. In step S23, the arithmetic processing unit 110 reads the regression equation corresponding to the occlusal facet P _{i from} which the inclination angle φ _i is derived from the auxiliary storage device 114, and the sagittal adjustment bending angle θ _S derived in step S22. and the value of the lateral adjusting the bending angle theta _H, derives an inclination angle phi _i to be applied to the occlusal facet P _i by substituting to the regression equation. The subscript i is a code for identifying the 106 occlusal facets. Here, an integer of 1 to 106 is used. When the inclination angle φ _i is derived for the occlusal facet of the right molar prosthesis, the sagittal adjustment curve angle θ _S derived based on the adjustment curve plane R specified for the right dentition and The value of the side adjustment curvature angle θ _H is used. On the other hand, when the inclination angle φ _i is derived for the occlusal facet of the left molar artificial tooth, the sagittal adjustment curve angle θ _S derived based on the adjustment curve plane R specified for the left dentition and The value of the side adjustment curvature angle θ _H is used.

In step S24, the arithmetic processing unit 110 stores the tilt angle data indicating the tilt angle φ _i derived in step S23 in the auxiliary storage device 114.

  In step S25, the arithmetic processing unit 110 determines whether or not the derivation of the inclination angle has been completed for all the occlusal facets on the 106 faces. If the arithmetic processing unit 110 determines that the derivation of the inclination angle has not been completed for all the occlusal facets, the processing proceeds to step S26. In step S26, the arithmetic processing unit 110 increments the value of i by 1, and returns the process to step S23. On the other hand, if it is determined in step S25 that the derivation of the inclination angle has been completed for all the occlusal facets, the arithmetic processing unit 110 ends this routine. The arithmetic processing unit 110 executes the tilt angle derivation processing program, thereby deriving the tilt angle to be given to each of the 106 occlusal small surfaces. The number and arrangement of the occlusal facets are not limited to those shown in FIG. 8 and can be changed as appropriate.

  Hereinafter, a method for deriving the mathematical formula represented by the formula (1) will be described with reference to the flowchart shown in FIG.

In step S31, a plurality of types of dentures having different combinations of sagittal adjustment curve angle θ _S and side adjustment curve angle θ _H are manufactured. In the present embodiment, as shown in FIG. 10, sagittal adjustment bending angles θ _S1 , θ _S2 , θ _S3 (θ _S1 <θ _S2 <θ _S3 ) and side adjustment bending angles θ _H1 , θ _H2 , θ _H3. Nine kinds of upper and lower jaw full dentures (dentures 1 to 9) having different combinations of (θ _H1 <θ _H2 <θ _H3 ) were manufactured.

In step S32, the occlusal surface of the artificial tooth is adjusted for each of the plurality of types of dentures manufactured in step S31. In the present embodiment, the occlusal surfaces of the artificial teeth were adjusted so that the dentures 1 to 9 were respectively attached to the average value articulator to become a functional occlusal surface. Specifically, as shown in FIG. 8, each molar artificial tooth arranged in the upper jaw is formed with 52 occlusal facets each having an appropriate inclination angle, and arranged in the lower jaw. 54 occlusal facets each having an appropriate inclination angle were formed. Since the dentures 1 to 9 have different combinations of the sagittal adjustment curve angle θ _S and the side adjustment curve angle θ _H , different inclination angles are given even to the occlusal facets at the same location.

  In step S <b> 33, the three-dimensional data of each of the plurality of types of dentures whose occlusal surface adjustment is completed is taken into the CAD / CAM system 100. In the present embodiment, each of the dentures 1 to 9 whose occlusal surfaces have been adjusted is scanned with an optical scanner, whereby three-dimensional data of the dentures 1 to 9 is acquired, and this is acquired by the CAD / CAM system 100. The data was stored in the auxiliary storage device 114.

In step S34, using the CAD / CAM system 100, the inclination angle of each occlusal facet of each denture is measured based on the three-dimensional data of each of the plurality of types of dentures, and each of the measured inclination angles is occluded. A database associated with the facet identification information (information indicating which occlusal facet is selected from a plurality of occlusal facets) is constructed. In this embodiment, using the CAD / CAM system 100, for each of the dentures 1 to 9, the inclination angles of all the occlusal facets (106 faces per denture) with respect to the XYZ coordinate axes are measured, and the obtained inclinations are obtained. A database was constructed in which each corner was associated with occlusal facet identification information (information indicating which occlusal facet out of 106 faces). FIG. 11 is a diagram showing an example of the database 50 constructed in this step. As shown in FIG. 11, the inclination angles φ _{11 to} φ ₉₁₀₆ measured for each of the dentures 1 to 9 are recorded in the database 50 in association with the identification information of the occlusal facets P _{1 to} P _106. Yes.

In step S35, using the database constructed in step S34, a mathematical expression indicating the relationship between the sagittal adjustment curvature angle θ _S and the lateral adjustment curvature angle θ _H and the inclination angle φ _i of the occlusal facet P _i is derived. To do. In the present embodiment, based on the inclination angle phi ₁₁ to [phi] ₉₁₀₆ recorded in the database 50, the inclination angle phi _i occlusal facets P _i intended variables, sagittal adjust the bending angle theta _S and lateral adjusting the bending angle By performing regression analysis using a linear model with θ _H as an explanatory variable, a regression function of a linear function as expressed by equation (1) was derived for each of the occlusal facets P _{1 to} P ₁₀₆ . In equation (1), a _i and b _i are partial regression coefficients corresponding to the occlusal facet P _i , and c _i is a constant term corresponding to the occlusal facet P _i . When the relationship between the sagittal adjustment curvature angle θ _S and the side adjustment curvature angle θ _H and the inclination angle φ _i does not match the linear model, a regression equation may be derived using a nonlinear model.

  In step S36, the derived regression equation is taken into the CAD / CAM system 100. In the present embodiment, the regression equation individually derived for each of the 106 occlusal facets formed on one denture is stored in the auxiliary storage device 114 of the CAD / CAM system 100 as mathematical data 220.

As is clear from the above description, the CAD / CAM system 100 uses mathematical expressions indicating the relationship between the sagittal adjustment curvature angle θ _S and the lateral adjustment curvature angle θ _H and the inclination angle φ _i of the occlusal facet P _i. It is held as mathematical formula data 220. After completing the arrangement of the virtual artificial teeth, the CAD / CAM system 100 derives the sagittal adjustment curve angle θ _S and the side adjustment curve angle θ _H and substitutes these into the above equation to thereby calculate the occlusal facets. An inclination angle to be given to each is derived, and NC data (second NC data) corresponding to the derived inclination angle is generated. The NC machine tool cuts the artificial tooth based on the second NC data with respect to the denture with the artificial tooth fixed. Thereby, the form correction of the occlusal surface of the artificial tooth is completed.

  Thus, according to the manufacturing method of the denture based on embodiment of this invention, the form correction of the occlusal surface of the artificial tooth conventionally performed by manual work can be automated using NC machine tool. . That is, from the denture base cutting to the occlusal surface shape correction can be completed inside the NC machine tool, and the conventional manual occlusal surface shape correction becomes unnecessary. Thus, by automating the occlusal surface form correction, it becomes possible to improve the productivity of dentures, reduce the production cost, and stabilize the quality.

  According to the method for manufacturing a denture according to this embodiment, the patient-specific occlusal facet is mechanically created by paying attention to the relationship between the occlusal facet that forms the occlusal face and the adjustment curve. The occlusal surface shape according to the shape of the ridge can be formed with a special specification. In particular, in the case of all dentures, the curvature proposed by Mr. Spee, Wilson, and Monson in the natural dentition and the adjustment curvature in the artificial dentition are often different. In other words, in the case of all dentures, in consideration of stability in the oral cavity, steeply inclined surfaces that tend to develop near the last molar equivalent of the mandibular ridge tend to have a stronger sagittal adjustment curve, Depending on how the projected upper and lower molar ridges overlap, there is a tendency to increase the lateral adjustment curve. In this way, after the loss of teeth, it is affected by the shape of the jaw ridge that has been freely absorbed and changed, so that the planting position and the inclination angle from which the natural tooth originally originated are different from those of the complete denture. In order to represent the occlusal facets of the upper and lower jaws from the characteristics of the adjustment curve in the artificial dentition as described above, the form of the occlusal face of the artificial teeth must be corrected in a machine tool that is mathematically accurately controlled. Is preferred.

  Moreover, you may use the special pre-made artificial tooth whose occlusal surface form is completely non-anatomical as a molar part artificial tooth used for manufacture of a base denture. In other words, the occlusal surface is blocked by a plane including all the cusps on the near-distal side and the buccal tongue side, so that the denture part artificial tooth having a completely flat occlusal surface is manufactured. Also good. Further, as the anterior tooth artificial tooth used for the manufacture of the denture, a special pre-made artificial tooth having a completely nonanatomical shape in the side of the tongue, the incision, and the tip may be used.

  Thus, in the method for producing a denture according to the present invention, it is possible to produce a denture using an artificial tooth in which at least one of the occlusal surface form and the polished surface form of the artificial tooth is non-anatomical. Is possible. Hereinafter, such a non-anatomical special artificial tooth is referred to as a flat artificial tooth. FIG. 12A is a diagram illustrating an appearance of a flat artificial tooth (molar part) 20A having an occlusal surface incomplete. FIG. 12 (B) is a diagram showing an external appearance of a flat artificial tooth (anterior tooth portion) 20B having an incomplete cutting edge shape. When using a flat artificial tooth and arranging virtual artificial teeth on CAD, a digital occlusal surface derived from a natural tooth shape is virtually assigned to each occlusal surface, and virtual artificial teeth are arranged. It is preferable.

  By using a non-anatomical artificial prosthesis, it becomes possible to positively correct the shape so as to become, for example, a non-cusp artificial tooth as designed by CAD. In addition, it is possible to dynamically modify the occlusal surface form that can provide an occlusal pattern such as lingualized occlusion. That is, by using nonanatomical artificial teeth, it is possible to perform large-scale shape correction freely and accurately into anatomical, functional, and physiological artificial tooth forms. According to the method for manufacturing a denture according to the present embodiment, the occlusal surface can be mechanically corrected, and such a large-scale shape correction can be easily performed.

  Conventionally, unoccupied artificial teeth and artificial teeth for lingualized occlusion have to be procured individually from companies each time, and when using CAD, many artificial teeth from multiple companies are used. There was a need to collect digital information about tooth morphology. However, most of the digital information related to the shape of the ready-made artificial tooth is usually protected by a patent law or the like, and it is difficult to collect digital information related to the artificial tooth shape of various concepts from a plurality of companies. If flat artificial teeth are used in the manufacture of a denture, large-scale shape correction can be performed by the output of the design using the CAD / CAM system. Therefore, it is not necessary to individually procure several types of artificial teeth having different morphological characteristics. For example, since only a few types of flat artificial teeth with different sizes and materials need to be stocked, the cost required for artificial tooth procurement can be reduced. In some cases, the operator himself / herself may make a flat artificial tooth and disclose digital information about the artificial tooth form to the denture manufacturing factory. Therefore, it is not necessary for a large-scale denture manufacturing factory to hold all kinds of artificial teeth made by other companies and their digital information in order to meet the demands of the surgeon. Therefore, the concentration of production processes can be facilitated, and as a result, a production system that can be used industrially can be constructed at low cost. As a result, not only can the manufacturing cost of dentures be reduced, but the merit of the dentures and the freedom of expression of the individuality can be greatly improved by mechanization of the manual work process, and the effect can be expected very much.

10 denture base 20 artificial tooth 30 base denture 50 database 100 CAD / CAM system 110 arithmetic processing unit 140 auxiliary storage unit 200 CAD program 210 CAM program 220 mathematical formula data

Claims (9)

A first step of constructing a three-dimensional model of a denture having a denture base and a plurality of artificial teeth arranged on the denture base;
A second step of generating first NC data for producing the denture base using an NC machine tool based on the three-dimensional model of the denture;
Based on the inclination of the plane including the predetermined points of the plurality of artificial teeth specified from the three-dimensional model of the denture, it should be applied to each occlusal facet of at least some artificial teeth of the plurality of artificial teeth A third step of deriving the tilt angle;
A fourth step of generating second NC data for forming an occlusal facet having an inclination angle derived in the third step on the at least some artificial teeth using an NC machine tool;
A method for manufacturing a denture containing a denture. A fifth step of producing the denture base using an NC machine tool to which the first NC data is input;
A sixth step of fixing the plurality of artificial teeth to the denture base manufactured in the fifth step;
A seventh step of forming an occlusal facet having the inclination angle on the at least some artificial teeth using an NC machine tool to which the second NC data is input;
The manufacturing method according to claim 1, further comprising:   The manufacturing method according to claim 1 or 2, wherein, in the third step, the inclination angle is derived by substituting a numerical value corresponding to the inclination of the adjustment curved plane into a predetermined mathematical expression corresponding to each occlusal facet. The processing in step 6 is performed inside the NC machine tool used in the fifth step,
The manufacturing method according to claim 2, wherein the processing in the seventh step is performed using the NC machine tool used in the fifth step. After the completion of the fifth step, the denture base is taken out from the NC machine tool used in the fifth step, and the processing in the sixth step is performed.
The manufacturing method of Claim 2 which installs the said denture base in the original position of the NC machine tool used in the said 5th process after the completion of the said 6th process, and performs the process in the said 7th process.   The manufacturing method according to any one of claims 1 to 5, wherein each of the plurality of artificial teeth is non-anatomical in at least one of an occlusal surface form and a polished surface form.   The occlusal surface of the molar artificial tooth of the plurality of artificial teeth is planar when the occlusal surface is closed by a plane including all cusps on the near distal side and the buccal tongue side. The manufacturing method as described in. A process of deriving a numerical value corresponding to the inclination of the plane including the predetermined points of the plurality of artificial teeth based on a three-dimensional model of the denture having a denture base and a plurality of artificial teeth arranged on the denture base,
A process of deriving an inclination angle to be given to each occlusal facet of at least some of the artificial teeth by substituting the numerical value into a predetermined mathematical formula,
A program that causes a computer to execute. A first value for deriving a numerical value corresponding to an inclination of a plane including a predetermined point of the plurality of artificial teeth based on a three-dimensional model of a denture having a denture base and a plurality of artificial teeth arranged on the denture base. Deriving means;
Second derivation means for deriving an inclination angle to be given to each occlusal facet of at least some of the artificial teeth by substituting the numerical value into a predetermined mathematical formula;
Design support device for plate dentures.