Patent Publication Number: US-2021161627-A1

Title: Method for designing denture, method for producing denture and positioning means

Description:
This application is a divisional application of U.S. application Ser. No. 15/725,511 filed Oct. 5, 2017, which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates to dentures and, in particular, a method for designing and producing dentures, and a positioning means used when dentures are produced. 
     BACKGROUND ART 
     One well-known method for making dentures is a lost wax technique. According to this technique, dentures can be obtained through the following steps: that is, first, an impression of a patient&#39;s intraoral shape is taken using an impression material (so-called impression taking). Plaster is poured to the impression and solidified, to make a plaster cast. 
     Next, the height of dentures of the upper and lower jaws is secured using wax on the plaster cast, and artificial teeth are embedded in the wax, to be wax dentures (so called arrangement of artificial teeth). Then, these wax dentures are embedded in plaster or the like to be solidified. After a portion where the wax flows out is formed in the wax dentures, the wax is melt and washed away by hot water or the like. Whereby, only the arranged artificial teeth remain, and a cavity is formed at the portion where the wax existed. Then, resin or the like is poured to (packed into) the cavity, to be cured. Dentures can be obtained by breaking and removing the plaster. 
     As described above, the lost wax technique includes a lot of steps, and takes a long time to be completed. In addition, it is said that dental technicians have to be skilled if making dentures according to this technique. 
     In contrast, Patent Literatures 1 and 2 disclose techniques of making dental prostheses such as dentures using CAD/CAM. That is, information on designing and producing dental prostheses is treated as data using CAD/CAM. Finally, dental prostheses can be obtained by cutting out using an NC machine tool based on the data. 
     According to this, dental prostheses can be made with less steps than the lost wax technique for a shorter time than before. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: JP H9-206320A 
     Patent Literature 2: JP 2002-224143A 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, when dentures are made using CAD/CAM, it is necessary that: a denture base is cut out from a harder resin material than wax, to be made, and artificial teeth made from ceramics, resin, or the like are fit into recesses that are shaped on the hard denture base for artificial teeth fitted thereinto, to be arranged, and are fixed with adhesive. Doing so, artificial teeth get out of the designed position when the artificial teeth are actually arranged because the recesses for fitting the artificial teeth thereinto have to be shaped larger than the artificial teeth, which might cause the entire occlusal relationship designed by CAD to suffer. Any technique of attaching artificial teeth easily and accurately is necessary because positioning of artificial teeth is important as described above. 
     An object of the present invention is to provide a method for designing dentures according to which artificial teeth can be easily and accurately attached to a denture base, which is designed and shaped by CAD/CAM, when the artificial teeth are arranged on the denture base. The present invention also provides a method for producing dentures, and a positioning means used when dentures are produced. 
     Solution to Problem 
     The present invention will be described below. Here, reference signs attached to the description and drawings are provided together in parentheses for easy understanding. However, the present invention is not limited thereto. 
     The invention of claim  1  is a method for designing a denture ( 10 ) on a computer based on data on an intraoral shape (S 20 ), the method comprising: creating data on a shape of a denture base ( 20 ) based on the intraoral shape (S 22 ); creating data on a position of an artificial tooth ( 30 ) to be arranged on the denture base (S 23 ); and creating data on a shape of an occlusal guide ( 40 ) that is tabular and has a recess part corresponding to a position of the arranged artificial tooth in an occlusal surface side (S 24 ). 
     The invention of claim  2  comprises: creating data on a positioning means ( 50 ,  60 ,  70 ) to fix positions of the denture base ( 20 ) and the occlusal guide ( 40 ) (S 25 ) in the method (S 20 ) according to claim  1 . 
     The invention of claim  3  is a method for producing a denture ( 110 ) (S 1 ), the method comprising: designing the denture ( 10 ) according to the method of claim  1  (S 20 ); producing a demure base ( 120 ), an artificial tooth ( 130 ) and, an occlusal guide ( 140 ) based on said designing (S 31 ); arranging the produced artificial tooth on the produced occlusal guide (S 32 ); and arranging the artificial tooth, which is arranged on the occlusal guide, on the denture base (S 33 ). 
     The invention of claim  4  is a method for producing a denture ( 110 ) (S 1 ), the method comprising: designing the denture ( 10 ) according to the method of claim  2  (S 20 ); producing a denture base ( 120 ), an artificial tooth ( 130 ), an occlusal guide ( 140 ), and a positioning means ( 150 ,  160 ,  170 ) based on said designing; arranging the produced artificial tooth on the produced occlusal guide (S 32 ); and arranging the artificial tooth, which is arranged on the occlusal guide, on the denture base (S 33 ), wherein in said arranging the artificial tooth on the denture base, a positional relationship between the denture base and the occlusal guide is determined by the positioning means. 
     The invention of claim  5  is a positioning means ( 150 ) that is used when a denture ( 110 ) is produced, wherein the positioning means is a means to couple a denture base ( 120 ) to an occlusal guide ( 140 ) that has a recess part corresponding to a position of an artificial tooth ( 130 ) in an occlusal surface side. 
     The invention of claim  6  is a positioning means ( 160 ) that is used when a denture ( 110 ) is produced, the positioning means comprising: a denture base keeping member that keeps a posture of a denture base; and a coupling member that is included in an occlusal guide ( 140 ) having a recess part corresponding to a position of an artificial tooth ( 130 ) in an occlusal surface side, and that is coupled to the denture base keeping member. 
     Advantageous Effects of Invention 
     According to the present invention, artificial teeth can be easily and accurately attached to a denture base that is designed and shaped by CAD/CAM. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a flowchart of a method for producing dentures S 1 ; 
         FIG. 2  is a flowchart of a step of designing dentures S 20 ; 
         FIG. 3  is a flowchart of a step of producing dentures S 30 ; 
         FIG. 4  is an external view of a denture base  20 ; 
         FIG. 5A  is an external view of artificial teeth  30 , and  FIG. 5B  is a cross-sectional view of an artificial tooth  30 ; 
         FIG. 6  is an external view of a denture  10 ; 
         FIG. 7A  is an explanatory perspective view of an occlusal guide  40 , and  FIG. 7B  is an explanatory schematic view of the occlusal guide  40 ; 
         FIG. 8  is a perspective view of the occlusal guide  40 ; 
         FIG. 9A  is an explanatory view of a positioning means  50 , and  FIG. 9B  shows the positioning means  50  separating; 
         FIG. 10  is an exploded perspective view of a positioning means  60 ; 
         FIG. 11  shows the positioning means  60  combining; 
         FIG. 12  is an explanatory view of a positioning means  70 ; 
         FIG. 13  is an explanatory view of arranging artificial teeth on an occlusal guide S 32 ; 
         FIG. 14  is an explanatory view of arranging artificial teeth on dentine bases S 33 ; 
         FIG. 15  is an explanatory view of arranging artificial teeth on denture bases S 33 ; and 
         FIG. 16  is an explanatory view of arranging artificial teeth on denture bases S 33 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The present invention will be described below as shown in the drawings. It is noted that the present invention is not restricted to any embodiments of the drawings. 
       FIG. 1  is an explanatory view of one embodiment, and is a flowchart of a method for producing dentures S 1 . As is seen from this, the method for producing dentures S 1  includes digitalizing an intraoral shape S 10 , designing dentures S 20 , and producing dentures S 30 . Hereinafter these steps will be described. 
     In digitalizing an intraoral shape S 10 , three-dimensional data of an intraoral shape is obtained indirectly front an obtained impression or directly from the inside of an oral cavity. A method of three-dimensional metrology on a plaster cast that is obtained through impression taking according to a known method can be used for obtaining the three-dimensional data from the impression. An intraoral three dimensional scanner can be used for obtaining the three-dimensional data directly from the inside of an oral cavity. 
     From this, the intraoral shape including information on a shape of a patient&#39;s mucosae is digitized. At this time, for example, data on occlusion can be obtained by three-dimensional metrology on impressions of upper and lower jaws combined in the same way as a position of patient&#39;s jaws. 
     In designing dentures S 20 , a shape of dentures are designed and determined on a computer based on the data obtained in digitalizing an intraoral shape S 10 .  FIG. 2  is a flowchart of designing dentures S 20 . As is seen from this, designing dentures S 20  includes obtaining intraoral data S 21 , designing denture bases S 22 , designing arrangement of artificial teeth S 23 , designing an occlusal guide S 24 , and designing a positioning means S 25 . 
     It is noted that all of dentures  10 , denture bases  20 , artificial teeth  30 , an occlusal guide  40  and positioning means  50 ,  60  and  70  to be described in this designing dentures S 20  mean embodiments formed on a computer as data. 
     Obtaining intraoral data S 21  is a step of obtaining the information on the intraoral shape, which was digitalized in digitalizing an intraoral shape S 10 , and taking the information in a design device (computer). This taking is stored in a memory in the computer via a receiving means that the computer includes. 
     In designing denture bases S 22 , the information obtained in obtaining intraoral data S 21  is modified if necessary, to design shapes of the denture bases  20 .  FIG. 4  schematically shows the denture base  20  in the upper jaw side. A denture base in the lower jaw side can be considered to have the same basic structure as in the upper jaw side although there is difference between upper and lower denture bases. Either one of them, or both of them is/are produced. 
     Denture bases are members that have functions of keeping artificial teeth at predetermined positions, and stably attaching dentures themselves onto oral mucosae. Thus, as is seen from  FIG. 4 , the denture base  20  finally has an embodiment of including a ridge part  21  that rises like a ridge as a portion where the artificial teeth  30  are arranged, and being provided with recess parts  22  on the top portion of the ridge part  21  where one end of each artificial tooth  30  is inserted, to fix the artificial teeth  30 . Positions and shapes of the recess parts  22  are determined by the artificial teeth  30  to be arranged. Thus, an embodiment of the recess parts  22  are determined after designing arrangement of artificial teeth S 23 . 
     A known method can be used for designing the denture bases  20  described above. 
     In designing arrangement of artificial teeth S 23 , the artificial teeth  30  are arranged according to designing denture bases S 22 . Information on artificial teeth is called from a database of the computer, and the artificial teeth  30  are arranged on the denture bases  20 . That is, based on the information taken so far, data on artificial teeth that matches dental arches is called from the database stored in the memory of the computer. This data is roughly arranged at a position on the ridge part  21  of each denture base  20 , and then, the position is finely adjusted. After the position is fixed by the fine adjustment, the recess parts  22  described above are formed in the denture bases  20  (see  FIG. 4 ). At this time, each recess part  22  has a little larger shape than an external form of each artificial tooth  30  in order for the artificial teeth  30  to be easily inserted into the recess parts  22 . 
     The artificial teeth  30  function instead of natural teeth. The artificial teeth  30  are artificial teeth made by being copied from natural teeth. As shown in  FIG. 5A , a plurality of artificial teeth  30  are arranged like natural teeth as necessary. In  FIG. 5A , the top side of the sheet is the occlusal surface side, the bottom side of the sheet is the denture base  20  side, and the transverse direction of the sheet is an arrangement direction.  FIG. 5B  is a cross-sectional view of the artificial tooth  30  taken along the line Vb-Vb in  FIG. 5A . This is a cross-section in the direction orthogonal to the arrangement direction. As seen from  FIGS. 5A and 5B , undercut pans  31  are provided for side faces that are in the direction orthogonal to the arrangement direction, at an end part of each artificial tooth  30  in the denture base  20  side. Whereby, the artificial teeth  30  are more firmly fixed to the denture bases  20 . 
     The artificial teeth  30  are arranged on the denture base  20 , to form the denture  10  as shown in  FIG. 6 . That is, the artificial teeth  30  are arranged on the recess parts  22  of the denture base  20 , to form the denture  10 . 
     In designing an occlusal guide S 24 , the occlusal guide  40  that is arranged between the occlusal surfaces of upper and lower rows of teeth is designed. The occlusal guide  40  is a tabular member into which occlusal relationship between the occlusal surfaces of artificial teeth (or artificial and natural teeth) of the upper and lower jaws is copied.  FIGS. 7A to 8  are explanatory schematic views.  FIG. 7A  is an obliquely schematic view of a scene where the occlusal guide  40  is arranged between the dentures  10  of upper and lower jaws, and  FIG. 7B  is a front schematic view of this scene.  FIG. 8  is a perspective view of the occlusal guide  40 . 
     As is seen from  FIGS. 7A, 7B and 8 , the occlusal guide  40  is an arcuate plate along rows of teeth. The occlusal surfaces of upper and lower rows of teeth are copied into both sides of the occlusal guide  40 . Therefore, the occlusal guide  40  includes information on the positional relationship between upper and lower rows of teeth under their occluding state. That is, as seen from  FIG. 8 , recess parts  41  that correspond to the shapes of the artificial teeth  30  in the occlusal surface sides are formed on the occlusal guide  40 . 
     The thickness of the occlusal guide  40  is not restricted. The occlusal guide  40  is preferably structured so that artificial teeth  130  can be inserted into and kept in recess parts  141  of an occlusal guide  140  when the actual occlusal guide  140  is produced based on the data of the occlusal guide  40  as described later. 
     In designing a positioning means S 25 , a positioning means for keeping the positional relationship between the denture bases  20 , the artificial teeth  30  and the occlusal guide  40  is designed. Whereby, arrangement of the artificial teeth  130 , including their occluding state, can be performed accurately (as designed) when the artificial teeth  130  are arranged on the denture bases  120 , which are actually produced, as described below. 
       FIGS. 9A and 9B  are explanatory views of the positioning means  50  according to the first embodiment.  FIGS. 9A and 9B  are views taken in the same direction as  FIG. 7B .  FIG. 9A  shows a posture when the positioning means  50  is combined, and  FIG. 9B  shows a posture when the positioning means  50  is separated. 
     The positioning means  50  is configured by having denture base connection members  51 , an occlusal guide connection member  52 , and a coupling member  53  as seen from  FIGS. 9A and 9B . Here, the denture base connection members  51  are members to detachably connect to the denture bases  20 , and the occlusal guide connection member  52  is a member to detachably connect to the occlusal guide  40 . The coupling member  53  is a member to couple the denture base connection members  51  to the occlusal guide connection member  52 . In this embodiment, a joint part  52   a  is provided so that connection and separation can be performed at some part of the coupling means  53 . 
     A protrusion  50   a  and a hole  50   b  corresponding thereto are provided for each connection part of the denture base connection members  51  and the denture bases  20 , connection part of the occlusal guide connection part  52  and the occlusal guide  40 , and joint part  52   a,  which prevents their positions when attached from getting out. 
     A shape of the positioning means  50  as described above is designed so that the denture bases  20  and the artificial teeth  30  are arranged, to enable the patient&#39;s occluding state to be reproduced. 
       FIGS. 10 and 11  are explanatory views of a positioning means  60  according to the second embodiment.  FIG. 10  shows a posture where the positioning means  60  is separated, and  FIG. 11  shows a posture where the positioning means  60  is combined. 
     The positioning means  60  is configured by having a denture base keeping member  61 , an occlusal guide connection member  62 , and coupling members  63  as seen from  FIGS. 10 and 11 . 
     Here, the denture base keeping member  61  is a member to keep the denture base  20  in a predetermined posture. It is noted that  FIGS. 10 and 11  are explanatory views of the positioning means  60 . Thus, illustration of the kept denture base  20  is omitted for easy understanding. As seen from  FIGS. 10 and 11 , a recess part  61   a  to keep the denture base  20  is provided for the denture base keeping member  61 , and is structured so as to keep the denture base  20  such that the denture base  20  does not move or rotate. 
     The occlusal guide connection member  62  is a portion to integrally connect to the occlusal guide  40 . In this embodiment, the occlusal guide connection member  62  is a crosslike member, and the coupling members  63  are formed at the tips thereof. 
     The coupling members  63  are members to couple the denture base keeping member  61  to the occlusal guide connection member  62 . In this embodiment the coupling members  63  are configured by three protrusions  63   a  provided for the tips of the occlusal guide connection member  62 , and grooves  63   b  into which the protrusions  63   a  are inserted, and which are provided for the denture base keeping member  61 . 
     According to such a positioning means  60 , the denture base  20  is arranged inside the recess part  61   a  of the denture base keeping member  61 . In contrast to this, the protrusions  63   a  are inserted into the inside of the grooves  63   b  as show in  FIG. 11 , to position the occlusal guide  40  and the denture base  20 . 
     Such a positioning means  60  also functions as well as the positioning means  50 , which makes it possible to accurately realize the designed arrangement of artificial teeth. 
       FIG. 12  is an explanatory view of a positioning means  70  according to the third embodiment. The positioning means  70  is an example of providing a positioning means for at least one tooth out of a group of rows of artificial teeth, and for the recess part  22  of the denture base  20  where this tooth is inserted. In the example of  FIG. 12 , one prismatic protrusion  70   a  that is one component of the positioning means  70  is arranged on the surface of the artificial tooth  30  which is opposite to the bottom surface of the recess part  22 , and a recess  70   b  that has a shape corresponding to the protrusion  70   a  is provided for the bottom surface of the recess part  22  at a position corresponding to the protrusion  70   a.  Whereby, the artificial tooth  30  for which the positioning means  70  is provided can be arranged on the recess part  22  of the denture base  20  (a recess part where the positioning means  70  is provided) only at the designed position in the designed direction. Therefore, other ordinary artificial teeth, positional relationship of which is determined by the occlusal guide, can be arranged on the recess parts  22  of the denture base  30  at the right positions in the right direction, following the artificial tooth  30  for which the positioning means  70  is provided. 
     According to such a positioning means  70 , no postprocessing (for example, removing the positioning means) is necessary because the positioning means  70  is hidden after dentures as an end product is manufactured. 
     Designing dentures S 20  is ended after going through the above described steps. 
     Returning to  FIG. 1 , designing dentures S 30  will be described.  FIG. 3  is a flowchart of producing dentures S 30 . 
     Producing dentures S 30  is a step of actually producing the components based on the data of the components designed in designing dentures S 20 , and combining them to produce dentures of high accuracy. Here, an example using the positioning means  50  will be described. As is seen from  FIG. 3 , producing dentures S 30  includes producing components S 31 , arranging artificial teeth on an occlusal guide S 32 , arranging artificial teeth on denture bases S 33 , and removing an occlusal guide and a positioning means S 34 . 
     In producing components S 31 , the data on the shapes of the denture bases  20 , the shapes of the artificial teeth  30 , the shape of the occlusal guide  40 , and the shape of the positioning means  50 , which are designed in designing dentures S 20 , are individually extracted, the extracted data is output to a machine tool as command data, the machine tool receives processing data, and the shapes are cutting out with the machine tool. This step itself can be performed according to a known method, including so-called processing by CAM. 
     Whereby, the actual denture bases  120  are produced using the denture bases  20  as data, the actual artificial teeth  130  are produced using the artificial teeth  30  as data, the actual occlusal guide  140  is produced using the occlusal guide  40  as data, and the actual positioning means  150  is produced using the positioning means  50  as data (the positioning means  160  and the positioning means  170  (which are not shown) are produced in the case of using the positioning means  60  and the positioning means  70 , respectively). 
     In arranging artificial teeth on an occlusal guide S 32 , the artificial teeth  130  in the occlusal surface sides are inserted into the occlusal guide  140 , to be arranged.  FIG. 13  schematically shows the arrangement. Proper arrangement can be performed as shown in  FIG. 13  because the recess parts  141  are formed on the occlusal guide  140  based on the occlusal surfaces of the artificial teeth  130  and thus, the shapes thereof match the artificial teeth  130 . The occlusal guide  140  and the artificial teeth  130  may be fixed with the minimum amount of adhesive or the like of low adhesion to make them not get out of each other if necessary. 
     Whereby, the positional relationship between the artificial teeth  130  including the occlusion becomes proper, and the arrangement of high accuracy for the design can be obtained. As described later, the whole rows of the artificial teeth  130  can be arranged with the occlusal guide at the same time, but not arranged one by one. Thus, artificial teeth can be efficiently arranged as the accuracy is kept. 
     In arranging artificial teeth on denture bases S 33 , the artificial teeth  130  arranged on the occlusal guide  140  are fixed to the denture bases  120 . In this embodiment, for example, S 33  is specifically carried out as follows.  FIGS. 14 to 16  shows explanatory views. 
     First, as shown in  FIG. 14 , resin  125  as adhesive is placed on the recess parts  122  of the denture bases  120 . Common resin that is used when an artificial tooth is fixed to a denture base can be used as this resin. 
     Next, in this example, the artificial teeth  130  are arranged on the denture base  120  in the upper jaw side in advance. At this time, as shown in  FIG. 15 , all of the artificial teeth  130  arranged on the occlusal guide  140  are pushed onto the denture base  120  in the upper jaw side, and each artificial tooth  130  is inserted into the recess part  122  corresponding thereto. At this time, the denture base connection part  151  of the positioning means  150  is coupled to the denture base  120 , and the occlusal guide connection part  152  is coupled to the occlusal guide  140 . The denture base connection part  151  and the occlusal guide connection part  152  are coupled by the coupling part  153 . 
     After that, the artificial teeth  130  are arranged on the denture base  120  in the lower jaw side. At this time, as shown in  FIG. 16 , all of the artificial teeth  130  arranged on the occlusal guide  140  are pushed onto the denture base  120  in the lower jaw side, and each artificial tooth  130  is inserted into the recess part  122  corresponding thereto. At this time, the denture base connection parts  151  of the positioning means  150  are coupled to the denture base  120 , and the occlusal guide connection part  152  is coupled to the occlusal guide  140 . The denture base connection parts  151  and the occlusal guide connection part  152  are coupled by the coupling part  153 . 
     As described above, the positional relationship between a plurality of the artificial teeth  130 , the positions of the artificial teeth  130  on the denture bases  120 , and the occlusal relationship between the upper and lower jaws are accurately realized by the occlusal guide  140  and the positioning means  150  according to the design. 
     At last, as shown in  FIG. 3 , in removing an occlusal guide and a positioning means S 34 , the occlusal guide  140  and the positioning means  150  are removed, to obtain the dentures  110 . 
     When the positioning means  160  or  170  is used, dentures can be obtained as well like the above example by combining the positioning means  160  or  170  as described above concerning the positioning means  60  and  70 . When the positioning means  170  is used, the positioning means  170  does not need to be removed. 
     REFERENCE SIGNS LIST 
     
         
           10  denture (data) 
           20  denture base (data) 
           30  artificial tooth (data) 
           40  occlusal guide (data) 
           50 ,  60 ,  70  positioning means (data) 
           110  demure 
           120  denture base 
           130  artificial tooth 
           140  occlusal guide 
           150 ,  160 ,  170  positioning means