JP5233456B2 - Crown design method and crown preparation method - Google Patents

Description

  The present invention relates to a crown design method and a crown creation method, and more particularly to a crown design method and a crown creation method for implant treatment using a CT image of a patient.

  In the conventional crown restoration method, the patient's dental plaster model is converted into an instrument that assumes the average temporomandibular joint size and movement of the patient, which is called an average articulator (or simply an articulator) as shown in FIG. The shape of the crown is determined by assuming an average jaw movement.

Specifically, a gypsum upper and lower tooth model produced by injecting gypsum into an intraoral impression is attached to an articulator. A dental technician virtually creates a crown with wax in the tooth defect portion of the tooth model. Then, the articulator is rotated and forward and laterally moved, and the upper and lower tooth plaster models are engaged to correct the crown shape of the wax. A restoration crown is prepared by a lost wax casting method using the wax crown prototype thus obtained. Finally, after the restoration crown is fixed in the patient's oral cavity, the metal crown is completed by performing occlusal adjustment by cutting the crown while allowing the patient to actually bite.
2002 Monthly Dental Technician volume "Basic knowledge of occlusion visually", Ishiyaku Shuppan Co., Ltd. (issued on August 25, 2002)

  However, the articulator generally used in the conventional crown restoration method averages the shape and movement of the patient's jaw, and it is difficult to accurately reproduce the patient's inherent jaw movement. For this reason, it is indispensable to adjust the occlusion after mounting the prepared restoration crown, which is a big problem to be solved in the treatment with the dental restoration.

In other words, the occlusal adjustment performed by shaving the crown while observing the actual occlusal state may take a very long time, and there is a problem that a physical burden is imposed on the patient. In addition, there is a problem that even if the occlusal adjustment is performed, a problem occurs in the meshing, and this causes temporomandibular disorders. These problems are due to the articulator failing to reflect the actual patient jaw size and movement.
In particular, teeth formed by implant treatment do not have periodontal ligaments that relieve impact unlike natural roots, so that the crown mounted on the implant has excessive force on the occlusal surface of the crown, especially in the lateral direction. It is necessary to consider patient-specific occlusal conditions so that no force is applied.

  Therefore, the present invention pays attention to the fact that a three-dimensional image of a patient's jaw bone is always taken in recent implant treatment, and moves the three-dimensional shape data of the patient's jaw bone by a computer so that the opposite teeth of the implant restoration tooth FGVP (Functionally Generated Virtual Path) is obtained, and the object is to design the shape of the implant crown restoration.

  The present invention relates to a method for designing a crown to be placed in a tooth defect using a computer including an input unit, an output unit, a storage unit, and a calculation unit, and the storage unit includes a patient's upper dentition and lower jaw. An acquisition step of acquiring a three-dimensional composite image having a tooth row, a placement step in which the calculation means places a three-dimensional crown image in a tooth defect portion of the three-dimensional composite image, and a maxillary tooth row of the three-dimensional composite image Detecting the contact area where the three-dimensional crown image is brought into contact with the corresponding tooth by being guided by the sliding movement of the upper and lower jaw joints, and the contact area as a three-dimensional crown image And a removing step for removing from the crown.

  The present invention also includes a step of outputting a three-dimensional crown image obtained by the crown design method to a CAM device via an output means, and a step of creating a crown from the three-dimensional crown image by the CAM device. It is also a method for preparing a dental crown including

  In addition, the present invention replaces a computer in order to design a crown to be placed in a tooth defect portion, by replacing a part of a 3D oral region image of a patient's oral region with a 3D dental model image of a patient's dental model. Means for obtaining a three-dimensional composite image having a maxillary dentition and a mandibular dentition, means for arranging a three-dimensional crown image in a tooth defect portion of the three-dimensional composite image, and a maxillary dentition of a three-dimensional composite image And the mandibular dentition are guided by a sliding motion between the upper and lower jaw joints to cause occlusal movement, and the jaw movement trajectory of the restoration tooth of the restoration tooth is recorded and displayed as FGVP, and the three-dimensional crown image is the opposite tooth. It is also a crown design program for functioning as a means for detecting a contact area that is in contact with the user and a means for removing the contact area from the three-dimensional crown image.

  Further, the present invention is a computer system for creating a crown using a three-dimensional composite image, wherein a part of the three-dimensional oral region image of the patient's oral region is a three-dimensional dental model image of the patient's dental model. A storage unit that stores the replaced three-dimensional composite image having a maxillary dentition and a mandibular dentition, and a crown image placement unit that places a three-dimensional crown image in a tooth defect portion of the three-dimensional composite image; A contact area detector that detects the contact area where the 3D crown image contacts the counter teeth by moving the upper and lower dentitions of the 3D composite image, and the 3D crown image of the contact area It is also a computer system for producing a crown, comprising a crown-shaped portion to be removed from the crown.

  By using the crown design method and the crown manufacturing method according to the present invention, it is possible to produce a crown for implant treatment according to the jaw shape of the patient and the like. Thereby, the occlusal adjustment of the crown mounted on the implant becomes almost unnecessary, the time required for the implant treatment can be shortened, and the pain and the economic burden on the patient can be greatly reduced.

  In addition, only one implant operation at a dental clinic can be performed in one day (8 hours) including preparation time. However, by adopting the present invention, two to three cases can be performed. This will also improve the operating efficiency and management efficiency of the clinic.

  An implant treatment method using a crown preparation method according to an embodiment of the present invention will be described. Such a treatment method includes the following steps 1 to 11.

  In steps 1 to 4, a part of the 3D-CT image (three-dimensional oral region image) of the patient's jawbone is replaced with a 3D-model image (three-dimensional dentition model image) to obtain a three-dimensional composite image.

  Step 1: A mold in which an impression of a patient's oral cavity is copied with a resin is formed. Next, gypsum is poured into the mold to produce a plaster model of the patient's dentition as shown in FIGS. 1A and 1B. FIG. 1A shows the upper dentition, and FIG. 1B shows the lower dentition. As a method for producing such a plaster model, a method conventionally used for dental treatment can be used.

Step 2: As shown in FIG. 2, a CT imaging template 10 used for X-ray CT (Computed Tomography) imaging of a patient's jawbone is prepared. The template 10 includes a dentition bite portion 1 and a marker portion 2.
The dentition bite portion 1 has a shape corresponding to each patient's dentition. Further, the dentition bite portion 1 is formed of a material that is not photographed with CT values (400 to 900) used for photographing the jawbone and the dentition model. Examples of such a material include a polymer material (instant polymerization resin) such as polymethyl methacrylate (PMMA), and a rubber-based material such as silicone, urethane, and thiocol.
On the other hand, the marker part 2 consists of a plate-shaped object formed with X-ray contrast agents, such as gypsum and barium sulfate. For example, a circular convex portion (or concave portion) having a diameter of 4 to 5 mm is partially provided on the surface of the marker portion 2. In the alignment process described later, the alignment accuracy is improved by aligning such convex portions.

  FIG. 3 shows a state in which the template 10 is bitten by the gypsum model 20 of the patient's dentition. In this state, the external shape data is acquired to obtain a 3D-model image (three-dimensional dentition model image). The shape of the dentition model can be obtained by using a contact type three-dimensional digitizer (for example, product surface: ATOS manufactured by GOM, Germany), a laser beam measurement device, a contact type measurement device, or the like. The shape of the dentition model may be formed from a CT image.

  Step 3: As shown in FIG. 4A, the CT imaging template 10 is attached to the patient 30. As described above, since the dental bite portion has a shape corresponding to each patient's dental row, the template is mounted when the patient bites the dental bite portion. FIG. 4B is a 3D-CT image (three-dimensional oral region image) of the patient's jawbone, which was taken in this state.

  Step 4: As shown in FIG. 5A (side view), the 3D-model image of the gypsum model is superimposed on the 3D-CT image of the patient's jawbone with the marker portion 2 of the template as a reference, and the patient's dentition is placed on the gypsum model. A 3D-CT image (three-dimensional composite image) replaced with is obtained. Specifically, a part of the 3D-CT image in a state where the marker part 2 of the 3D-CT image (FIG. 4B) of the patient's jaw bone and the marker part 2 of the 3D-model image (FIG. 3) of the gypsum model overlap. Is replaced with a 3D-model image (three-dimensional dentition model image). By making the convex part (or concave part) of the marker part 2 overlap, the accuracy of superposition improves.

  FIG. 5B is a 3D-model image obtained by measuring the shape of the dentition portion with high accuracy from a gypsum model using a contact-type three-dimensional digitizer. FIG. 5C shows the patient's dentition of the gypsum model of FIG. 5B. It is a 3D-CT image (three-dimensional composite image) replaced with a 3D-model image. As can be seen from FIGS. 5A to 5C, the 3D-model image of the dentition model is clearer than the 3D-CT image of the patient's dentition. The crown can be formed with high accuracy.

  In addition, when the artifact (video failure) 40 resulting from the metal restoration in the patient's oral cavity has occurred, it is removed from the 3D-CT image by image processing (trimming processing).

  Next, in Steps 5 to 7, a dental crown suitable for a patient is designed on a computer based on the 3D-CT image (three-dimensional composite image) obtained in Steps 1 to 4 described above. FIG. 6 is a flowchart of the crown design process.

Step 5: After acquiring a 3D-CT image (three-dimensional composite image) (S1), as shown in FIG. 7A, using this 3D-CT image, a portion of a tooth that requires implant treatment (a missing tooth) ) To simulate the arrangement of the crowns on the computer (S2).
Specifically, a standard dental crown selected from the database is arranged in a missing portion of a patient's tooth using a database of standard dental crown 3D images stored in advance in a computer memory. The standard crown is arranged in a state where the upper and lower teeth of the 3D-CT image are meshed at the central occlusal position, and the standard dental crown is placed at the position where the tooth missing part meshes with the counter tooth (position where the cusp contacts the fossa). Place and do. When there are residual teeth before and after the tooth defect portion, they are arranged so as to be in contact therewith. In the step of arranging the standard crown, the image of the standard crown may be enlarged / reduced linearly or nonlinearly, for example, in the vertical direction or the horizontal direction. Thus, what arranged the standard dental crown in a patient's 3D-CT image turns into a three-dimensional dental crown image.

  7B to 7D are diagrams in which standard crowns are arranged in a 3D-CT image of a patient. FIG. 7B shows an abutment that supports the standard crown, and FIG. 7C shows a standard placed on the abutment. FIG. 7D shows a cross section of a state in which the standard crown is arranged on the abutment.

  FIG. 8A to FIG. 8C are examples of standard crowns, and all crown shape data of upper and lower tooth rows are prepared. Since the crown shape varies depending on the age and sex of the patient, it is preferable that a plurality of standard crown shapes are stored in a database for each age, sex, race, and the like.

  When there are few remaining teeth, a standard crown is placed in consideration of the anatomical tooth arrangement of the maxilla and mandible. For example, the arrangement may be such that the position of the buccal cusp from the first premolar of the lower jaw to the last molar follows a curve called “Spie curve”. In addition, “Wilson curvature” may be considered for the left and right molars.

  For example, in the 3D-CT image of FIG. 7A, one of the rightmost innermost teeth of the patient and four of the leftmost innermost teeth are image-combined standard crowns. The position of the standard crown is determined from the position of the remaining teeth and the upper teeth.

  Step 6: Considering the patient's actual occlusal movement (mastication movement) on the computer, modify the tooth shape so that early contact and intercuspal interference do not occur, LGTP (Light Guide Tapping Position) and CLP (Clenching Position) ) Match (S3).

Specifically, while viewing the image on the display, the lower jaw of the three-dimensional composite image is moved forward and backward and / or laterally (left and right) from the state where the upper and lower dentitions of the three-dimensional composite image are engaged at the central occlusal position. Exercise. Here, the front-rear movement means that the lower jaw teeth move forward (or backward) from the cusp fitting position while maintaining the occlusal contact between the upper and lower jaw teeth. Lateral movement refers to movement of the mandible to the side (right or left). At this time, the condyle is side-shifted and rotated in the glenoid. The range of forward / backward movement and lateral movement is limited to the movement range of normal occlusal movement.
Then, the region where the 3D crown image overlaps with the opposing 3D composite image (opposite tooth), that is, the region where the 3D crown image is brought into contact with the counter tooth by being guided by the sliding motion of the upper and lower jaw joints. Detect as a contact area. It is preferable to perform marking such as coloring on the contact area. These contact areas can also be recorded as FGVP (Functionally Generated Virtual Path).

  Here, as a method for determining the occlusal surface form of the restoration crown without using an articulator, a FGP (Functionally Generated Path) method is conventionally used. In the FGP method, the movement of the occlusal surface during the functional sliding movement of the prosthetic teeth is recorded in wax placed in the patient's mouth or in an immediate polymerization resin (FIG. 9). Then, using this wax or resin as a model, an occlusal surface of a functionally harmonized prosthesis is created. The feature of this method is that the occlusal surface is formed by using the motion path formed by the motion of the patient's own jaw bone, so that the occlusal surface suitable for each patient can be produced with high accuracy. The FGVP method used in the present embodiment is a method in which the FGP method is performed on a computer (virtual space) using a three-dimensional composite image of a patient's upper and lower dentition.

An example of the FGVP method is shown in FIGS. FIG. 10A (side view) and FIG. 10B (front view) are three-dimensional composite images of a patient. When a standard crown is placed in a region (FGVP block) surrounded by a lower jaw frame, the contact occurs when an occlusal movement occurs. A route (FGVP) is determined. FIG. 10C is an FGVP formed on the standard crown when the lower jaw is occluded. In FIG. 10C, the lower side is the front (left side of FIG. 10A) and the upper side is the rear (right side of FIG. 10A). The left figure shows the FGVP formed in the standard crown when the lower jaw is moved forward, the middle figure is when the lower jaw is moved leftward, and the right figure is when the lower jaw is moved rightward. .
In addition, as the occlusal movement, an opening / closing opening movement or the like may be performed in addition to the forward movement or the side movement. Further, instead of moving the lower jaw, the upper jaw may be moved.

Here, the following various steps can be used as the contact path (FGVP) detection step.
In the detection step 1, the upper and lower jaw joints of the three-dimensional composite image are slid and / or the upper and lower dentitions are guided to move the upper and lower dentitions of the three-dimensional composite image on the computer. Thus, a region where the three-dimensional crown image contacts the counter tooth is detected as a contact region.
Here, the sliding motion of the upper and lower jaw joints is a motion in which the upper and lower jaws move relatively while sliding on the lower jaw of the lower jaw in the lower jaw socket of the upper jaw. In addition, the guide movement of the upper and lower dentitions is a movement in which the upper dentition and the lower dentition move relative to each other, and includes a translational motion in three axial directions and a rotational motion around the three axes.

  In another detection step, the lower jaw of the three-dimensional composite image is set according to the degree of freedom of the temporomandibular joint from the state where the three-dimensional composite image having the three-dimensional crown image is meshed at the central occlusal position on the computer. A sliding motion composed of a translational motion and a rotational motion is performed, and a region where the three-dimensional dental crown image overlaps the opposing three-dimensional composite image is detected as a contact region. The degree of freedom of the temporomandibular joint is defined by data on the movable range of the temporomandibular joint obtained from the actual movement of the temporomandibular joint.

In another detection step, a state where a three-dimensional composite image having a three-dimensional crown image is meshed at a central occlusal position on the computer, between the lower jaw and the upper jaw (upper and lower dentitions) of the three-dimensional composite image. Feedback control using the shortest distance, collision area, indentation volume, or a combination thereof to perform the sliding movement of the upper and lower temporomandibular joint and the guidance movement of the upper and lower dentition, and the three-dimensional facing three-dimensional crown image An area overlapping with the composite image is detected as a contact area.
Here, the shortest distance is the shortest distance between the upper and lower tooth rows when they do not contact. The collision area refers to the number of contact points and their positions when the upper and lower tooth rows contact each other. Further, the indentation volume refers to the volume of the overlapped (indented) portion because the upper and lower tooth rows may overlap (indent) on the computer.

In another detection step, a three-dimensional composite image having a three-dimensional crown image is meshed at the central occlusal position, and the freedom degree space of the temporomandibular joint is searched heuristically to optimally bite the upper and lower teeth. The upper and lower dentitions are guided and moved together, and the region where the three-dimensional crown image overlaps with the opposite three-dimensional composite image is detected as a contact region.
The degree of freedom space of the temporomandibular joint is defined by data on the movable range of the temporomandibular joint obtained from the actual movement of the temporomandibular joint as described above. Such data is defined by a combination of position data in the X-axis direction, Y-axis direction, and Z-axis direction, and angle data around the X-axis, Y-axis, and Z-axis.
As described above, for example, by performing a heuristic search based on an empirical rule, it is possible to obtain the optimum meshing of the upper and lower teeth more quickly.

In another detection step, the shortest distance between the upper and lower dentitions of the three-dimensional composite image from the state where the three-dimensional composite image having the three-dimensional crown image is meshed at the central occlusal position on the computer. A heuristic search for the degree of freedom of the temporomandibular joint using area, volume of indentation, or a combination thereof, and three-dimensional dental crown images that guide the upper and lower teeth to guide the upper and lower teeth. Is detected as a contact area.
As described above, when performing a heuristic search, it is preferable to use the shortest distance between the upper and lower dentition, the collision area, the recessed volume, or a combination of these data.

  In another detection step, the lower jaw of the three-dimensional composite image is set according to the degree of freedom of the temporomandibular joint from the state where the three-dimensional composite image having the three-dimensional crown image is meshed at the central occlusal position on the computer. When performing translational movement and / or rotational movement, or when heuristically searching the freedom degree space of the temporomandibular joint, the shortest distance, collision area, and contact between the three-dimensional crown image and the opposite three-dimensional composite image Using the area and the embedded volume, or a combination thereof, the three-dimensional crown image can be deformed linearly (eg, by affine transformation) or non-linearly.

  As described above, in the contact area detection step of Step 6, it is preferable to obtain an optimal meshing of the upper and lower tooth rows using a computer, and to detect the contacting portion of the upper and lower tooth rows as the contact area. In particular, optimal meshing can be detected more quickly by performing a heuristic search.

  In these detection steps, each patient is informed of the optimal meshing of the upper and lower dentitions using a computer based on patient-specific data such as 3D composite image data and temporomandibular joint freedom space data. It is possible to accurately and quickly obtain the optimum meshing according to the condition. Thereby, compared with the conventional FGP method, the design of the implant more suitable for a patient is attained.

  Step 7: The detected contact area is deleted from the three-dimensional crown image, and the shape of the three-dimensional crown image is corrected to match the patient's occlusal movement (S4). In addition, the contact area indicated by FGPV created in Step 6 can be deleted from the three-dimensional crown image, or the portion where the gap is generated due to the shortage can be enlarged and brought into contact. For example, a part of the three-dimensional crown image including the contact area is reduced linearly or nonlinearly to remove the contact area. More specifically, the upper half of the three-dimensional dental crown image is reduced in the vertical direction in FIG. 5B so that the cusp head of the three-dimensional dental crown image does not contact the opposing dentition. Thus, a custom-made crown shape suitable for each patient can be designed.

  FIG. 11A shows a state in which the standard crown is placed on the lower jaw, and FIG. 11B shows the FGPV formed on the standard crown as a result of Step 6. As shown in FIG. 11C, the shape of the standard crown (left figure) is corrected so that the FGPV shown in FIG. 11B does not occur, and the adjusted crown shape shown in the right figure is obtained.

  In steps 6 and 7, the occlusal movement of the 3D-CT image on the display is used to cut the region where the standard crown contacts the opposing tooth, or the interval between the standard crown and the counter tooth is increased. The standard crown may be expanded for large portions.

  In addition, after removing the contact area, the shortest distance between the three-dimensional crown image when the occlusal movement is performed and the opposite three-dimensional composite image is preferably from 0 (both are in contact) to about 50 μm. The doctor gives instructions after understanding the condition of the bones and implants and the state of meshing, and simulates the preferred meshing. This is because by providing a small gap between the two, a lateral force is not applied to the implant when the patient performs an occlusal motion, and damage to the implant can be prevented.

  Further, as a 3D-CT image actually used, for example, a 3D-CT image in the vicinity of the dentition as shown in FIG. That is, if there is 3D-CT of the lower jaw including the upper and lower dentition, a part of the upper jaw including the mandibular fossa, and the condyle moving in the lower jaw fossa, the occlusal movement can be performed.

  As mentioned earlier, the conventional method for determining the shape of the occlusal surface of the restoration crown by determining the movement path of the opposing teeth from the occlusal movement using the average value articulator has been performed. This method cannot accurately reproduce the patient's original occlusal movement, and it is essential to adjust the occlusion in the oral cavity after the crown is mounted. On the other hand, in this embodiment, since the patient's specific occlusal movement is reproduced on the computer using the jaw movement software on the patient's 3D-CT image, the shape of the occlusal surface of the restoration crown is more accurately represented. Can be determined. Such a method is called an FGVP (Virtual FGP) method. The FGVP may be obtained by performing jaw movement while a VR haptic device (haptic device) feels the contact force with the opposing teeth.

  A hole for fixing with the implant or the abutment is provided in the crown shape obtained by the above design process. Specifically, after determining the fixing position of the implant or abutment in the following steps, the data of the portion where the abutment or the like is inserted is subtracted from the crown data so that it can be fixed thereto. The final crown shape data is sent to the CAM device via, for example, an output unit, and a crown according to the crown shape data is formed by the CAM device. The crown is made of, for example, ceramics or resin, and is manufactured using a cutting method or a rapid prototyping method.

  Next, in steps 8 and 9, a surgical guide used for implant positioning is designed. The implant is used to fix the crown designed in the above process to the patient. In addition, you may perform the design process (process 8 and 9) of a surgical guide prior to these separately from a crown design process (process 5-7).

Step 8: As shown in FIGS. 13 to 15, a surgical guide for assisting in implant surgery is designed on a computer.
Specifically, first, the implant is fixed so as to avoid the mandibular canal while observing the shape of the mandible and the position of the mandibular canal through which nerves, arteries and veins appear on the 3D-CT image of the patient shown on the display or the like. Determine the position. FIG. 13 is a simulation image of the arrangement of the implant fixed to the lower jaw (displayed translucently) so as to avoid the lower canal and the crown fixed using the abutment on the implant.

  Next, a surgical guide used to form a hole in the lower jaw to secure the implant to the lower jaw as shown in FIG. 14 is designed. FIG. 15 shows a surgical guide superimposed on the image of FIG. In designing the surgical guide, for example, Free Form software (trade name) and a haptic device (for example, trade name: PHANToM manufactured by SensAble Technologies, USA) (FIG. 16) are used.

  Step 9: The shape data of the surgical guide designed on the computer (for example, shown in FIG. 17) is output to the CAM device (FIG. 18) via the output unit, and the surgical guide is actually formed by the CAM device.

  FIG. 19 is an overall photograph of a surgical guide with a titanium drill guide (CT planning tube). FIG. 20 is a photograph of a state where the surgical guide is actually mounted on the lower jaw (the position of the right back tooth). The surgical guide is made of acrylic, for example, and has a hole along the direction in which the implant is formed. It is preferable that a drill guide such as titanium is provided on the wall surface of the hole.

  Finally, in Steps 10 to 11, the crown is fixed to the patient's dentition defect using an implant or the like.

  Step 10: As shown in FIG. 21, a surgical guide is put on the patient's lower jaw, and a drill is inserted into the hole of the surgical guide to form a hole in the lower jaw. Subsequently, after removing the surgical guide, the implant is inserted into the hole of the formed mandible and fixed. FIG. 22 is a photograph of the oral cavity with the implant and abutment fixed to the lower jaw. This makes it possible to accurately fix the implant at a position determined by simulation on a computer.

  Step 11: FIG. 23 is a schematic view of a state in which the crown is fixed via the abutment on the implant fixed to the lower jaw. As the abutment, a standard product is preferably used, but an original product may be designed in some cases. By using the original product, the crown can be fixed at an angle inclined from the fixing direction (longitudinal direction) of the implant. Even when an abutment having an original shape is manufactured, the shape data of the abutment can be transferred to the CAM device. It is also possible to fix the crown directly on the implant without using an abutment.

  FIG. 24 shows a state in which the crown produced using the 3D-CT image is fixed in the oral cavity of the patient using an implant or the like. Since such a crown is designed in consideration of the patient's occlusal movement, the occlusal adjustment is almost unnecessary only by fixing in the patient's oral cavity by implant treatment. For this reason, the burden on the patient in the implant treatment can be greatly reduced.

For example, in conventional implant treatment, it is necessary to fix the implant, fix the crown on it, and adjust the occlusion (partial deletion of the crown, etc.) according to the patient's engagement, Times usually ranged from 5 to 6 hours, and the physical burden was particularly excessive for elderly patients.
On the other hand, in the method according to this embodiment, since occlusal adjustment after fixing the crown is almost unnecessary, the operation time can be reduced to about 1 to 2 hours, and the burden on the patient is greatly reduced. It becomes possible.

FIG. 25 is a block diagram of the computer system 100 used in the above-described crown design method and crown manufacturing method. The computer system 100 includes an input unit 101 for inputting a 3D-CT image and the like, an output unit 102 for outputting crown design data to the CAM device, a storage unit 103 for storing standard dentition shape data and the like, and 3D such as occlusal movement -It has the display part 104 which displays the state of CT image.
The computer system 100 further includes a calculation unit 105. The calculation unit 105 includes a crown image placement unit 111 for placing a standard dental crown, and a contact region detection unit that detects a contact portion of a dentition by occlusal movement. 112, and a crown image correcting unit 113 for removing a contact area of the crown image.

Although a case where a 3D-CT image is created based on a CT image of a patient has been described here, the same can be done using a nuclear magnetic resonance (MRI) image.
In the embodiment of the present invention, the lower jaw is mainly described. However, the crown can be similarly designed for the upper jaw.

It is a maxillary dentition model. It is a dentition model of the lower jaw. It is a template for CT imaging. This is a state of CT imaging of the dentition model. This is a state of CT imaging of a patient. It is a 3D-CT image of a patient. 3D composite image (side view). It is a 3D-model image of a plaster model. It is a three-dimensional composite image (front surface). It is a flowchart of the crown design process concerning this invention. It is an enlarged photograph of the lower jaw part of a three-dimensional composite image. This abutment supports the standard crown. A standard crown placed on the abutment. It is a cross section of the state which has arrange | positioned the standard crown on the abutment. It is an example of a standard dental crown. It is an example of a standard dental crown. It is an example of a standard dental crown. It is an example of the recording of the movement of the occlusal surface using the conventional FGP method. It is an example of the FGVP method (side surface). It is an example of the FGVP method (front). FGVP formed on the occlusal surface of the standard crown. A standard crown is placed on the lower jaw. It is an example of FGVP recorded on the standard crown. Standard crown before and after correction. It is an example of the range of 3D-CT image used for FGVP method. It is a simulation image of the implant and abutment fixed to the lower jaw. It is a simulation image of a surgical guide placed on the lower jaw. The surgical guide is placed on the lower jaw. 1 is a schematic diagram of a haptic device. It is the shape data of the surgical guide designed on the computer. It is the external appearance of a CAM apparatus. It is the whole photograph of the surgical guide with a titanium drill guide. The surgical guide is mounted on the lower jaw (the position of the right back tooth). The patient's lower jaw is covered with a surgical guide. The implant and the abutment are fixed to the lower jaw of the patient. It is the schematic of the state by which the crown was fixed via the abutment on the implant fixed to the lower jaw. The prepared crown is fixed in the oral cavity of the patient. It is a block diagram of a computer system used for a crown design method and a crown manufacturing method according to the present invention. It is a general view of an average value articulator.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 Computer system 101 Input part 102 Output part 103 Storage part 104 Display part 105 Calculation part 111 Crown image arrangement part 112 Contact area | region detection part 113 Crown image correction part

Claims (15)

A method of designing a crown to be placed in a tooth defect using a computer including an input unit, an output unit, a storage unit, and a calculation unit,
The storage means acquires a three-dimensional composite image having a patient's maxillary dentition and mandibular dentition;
The computing means is
An arrangement step of arranging a three-dimensional crown image on a tooth defect portion of the three-dimensional composite image;
A detection step of detecting a contact area where the three-dimensional crown image is in contact with the corresponding tooth by causing the upper dentition and the lower dentition of the three-dimensional composite image to occlude;
Removing the contact area from the three-dimensional crown image;
Only including,
The three-dimensional composite image is an image obtained by replacing a part of a three-dimensional oral region image of a patient's oral region with a three-dimensional dental model image of the patient's dental model. . The acquisition step is
Inputting a three-dimensional oral region image of a patient's oral region having a marker into the computer via the input means;
Inputting a three-dimensional dentition model image of a dentition model of a patient having a marker to the computer via the input means;
The arithmetic means replaces a part of the 3D oral region image with the 3D dental model image in a state where the marker of the 3D oral region image and the marker of the 3D dental model image coincide with each other. Creating a three-dimensional composite image;
The crown design method according to claim 1 , further comprising the step of storing the three-dimensional composite image in the storage means. The placement step is
Placing a three-dimensional crown image selected from standard crown shape data of a plurality of upper and lower dentitions stored in advance in the storage device at a predetermined position of a tooth defect portion of the three-dimensional composite image; The crown design method according to claim 1, comprising: The placement step is
The upper and lower teeth of a three-dimensional synthetic image above in a state in which engaged in centric occlusion, according to claim 1 or 2, characterized in that it comprises the step of disposing the three-dimensional coronal image in a position to bite the opposite teeth The dental crown design method described in 1. The detection step is
The crown design method according to any one of claims 1 to 4 , further comprising a step of recording and displaying a jaw movement trajectory of a contact area with the counter tooth as FGVP. The detection step is
The upper and lower dentitions of the three-dimensional composite image are caused to occlude by the sliding movement of the upper and lower jaw joints and / or the guide movement of the upper and lower dentitions of the three-dimensional composite image, so that the three-dimensional crown image is obtained. The crown design method according to any one of claims 1 to 4 , wherein the method is a step of detecting a region in contact with the counter tooth as the contact region. The detection step is
From the state where the three-dimensional composite image having the three-dimensional crown image is engaged at the central occlusal position, the lower jaw of the three-dimensional composite image is composed of translational motion and rotational motion according to the degree of freedom of the temporomandibular joint. that gliding motion allowed to, according to any one of claims 1 to 4, said three-dimensional crown image is characterized in that a region overlapping with the 3-dimensional composite image that faces a step of detecting as the contact area Tooth crown design method. The detection step is
From the state in which the three-dimensional composite image having the three-dimensional crown image is meshed at the central occlusal position, the shortest distance, the collision area, the indentation volume, or their distance between the lower jaw and the upper jaw of the three-dimensional composite image Feedback control is performed using the combination, and the sliding movement of the upper and lower temporomandibular joints and / or the guidance movement of the upper and lower dentitions are performed, and the region where the three-dimensional crown image overlaps the opposing three-dimensional composite image is detected as the contact region. The crown design method according to any one of claims 1 to 4 , wherein the crown design method according to claim 1 is performed. The detection step is
From the state in which the three-dimensional composite image having the three-dimensional crown image is meshed at the central occlusal position, the degree of freedom space of the temporomandibular joint is searched heuristically to obtain the optimum meshing of the upper and lower teeth, and the upper and lower teeth 5. The step according to claim 1 , wherein the row is a step of detecting a region where the three-dimensional crown image overlaps with a facing three-dimensional composite image as the contact region by guiding the row. Tooth crown design method. The detection step is
From the state in which the three-dimensional composite image having the three-dimensional dental crown image is meshed at the central occlusal position, the shortest distance, the collision area, the indentation volume, or a combination thereof between the upper and lower teeth of the three-dimensional composite image To search the degree of freedom space of the temporomandibular joint with heuristics, find the optimal meshing of the upper and lower dentitions, guide and move the upper and lower dentitions, and the three-dimensional composite image in which the three-dimensional crown images face each other 5. The crown design method according to claim 1 , wherein a region overlapping with the contact region is detected as the contact region. The removal step is
From the state where the three-dimensional composite image having the three-dimensional crown image is meshed at the central occlusal position, the lower jaw of the three-dimensional composite image is subjected to translational motion and / or rotational motion according to the degree of freedom of the temporomandibular joint. In the case of heuristic search of the degree of freedom space of the temporomandibular joint, the shortest distance, the collision area, and / or the indentation volume between the three-dimensional crown image and the opposite three-dimensional composite image, or their volume The crown design method according to any one of claims 1 to 4 , which is a step of linearly or nonlinearly deforming the three-dimensional crown image using a combination. The removal step is
A part of the three-dimensional dental crown image including said contact area and reduce or enlarge the linear or non-linear, according to any one of claims 1 to 11, characterized in that the step of removing the contact area Tooth crown design method. A step of outputting a three-dimensional crown image obtained by the crown design method according to any one of claims 1 to 12 to the CAM device via the output means, and the three-dimensional tooth by the CAM device. And a step of creating a crown from the crown image. Computer to design the crown to be placed in the tooth defect,
Means for obtaining a three-dimensional composite image having a maxillary dentition and a mandibular dentition in which a part of a three-dimensional oral region image of a patient's oral region is replaced with a three-dimensional dentition model image of the patient's dentition model ,
Means for arranging a three-dimensional crown image on a tooth defect portion of the three-dimensional composite image;
The maxillary dentition and the mandibular dentition of the three-dimensional composite image are guided by a sliding motion between the upper and lower jaw joints, occluded, and the jaw movement trajectory of the restoration teeth is recorded and displayed as FGVP. Means for detecting a contact area where the three-dimensional crown image contacts the counter teeth;
A crown design program for functioning as a means for removing the contact area from the three-dimensional crown image. A computer system for producing a crown using a three-dimensional composite image,
A memory for storing a three-dimensional composite image having a maxillary dentition and a mandibular dentition in which a part of a three-dimensional oral region image of the patient's oral region is replaced with a three-dimensional dentition model image of the patient's dentition model And
A crown image placement portion for placing a three-dimensional crown image on a tooth defect portion of the three-dimensional composite image;
A contact area detecting unit for detecting a contact area in which the three-dimensional crown image contacts a counter tooth by causing the upper dentition and the lower dentition to occlude the three-dimensional composite image;
And a crown-shaped portion for removing the contact area from the three-dimensional crown image.