JP5181098B2 - Byte splint manufacturing method - Google Patents

Description

  The present invention relates to a method for producing a bite splint that is effective for supporting surgical correction (maxillary jaw osteotomy) for patients with jaw deformities.

  In order to restore correct occlusion for a patient with severe jaw deformity in dentistry, surgical correction by osteotomy of the upper jaw and / or lower jaw is performed in cooperation with an orthodontist and a dental oral surgeon. In doing so, it is a success or failure of the surgery to evaluate in advance which interference method or interference between the bone sections when moving the bone sections separated by the incision to the correct position, and to determine which surgical method is appropriate. Greatly affects.

  Traditionally, a bite splint created by orthodontists based on the positional relationship between the upper and lower jaws has been used to fix the upper and lower jaws during surgery. This bite splint is usually a two-dimensional X-ray photograph. It is made based on a paper surgery using a certain cephalogram. Here, FIG. 5 shows a cephalogram trace conventionally used.

  In this paper surgery, the orthodontist first determines the upper jaw as shown in FIG. 5B from the positional relationship in which the upper jaw and the lower jaw of the patient with jaw deformity before the operation shown in FIG. Sets the normal positional relationship between the lower jaw and the lower jaw. FIG. 5 (a) shows a cephalogram trace of the skull including the upper and lower jaws and dentition of a patient with jaw deformity before the operation, and a line (occlusion plane) 11 indicating the horizontal inclination of the jaw is the horizontal reference of the skull. It is inclined with respect to the face-ear plane 10 which is a line. FIG. 5B shows a state in which the movement of the lower jaw to the normal position is simulated by a paper surgery, and the line (occlusion plane) 12 is parallel to the line (face-ear plane) 10.

  Based on the normal positional relationship shown in FIG. 5 (b), the orthodontist makes a resin bite splint using a dental model based on his knowledge and experience. Thereafter, in an actual maxillomandibular osteotomy, the surgeon determines the osteotomy conditions based on the knowledge and experience while using the bite splint prepared by the orthodontist as described above.

  However, the bite splint using a paper surgery is based on a two-dimensional image simulation, and it is not possible to evaluate in advance the interference or gap between bone cuts during surgery. Therefore, when such a bite splint is used in an actual surgical correction performed in three dimensions, there is a possibility that a three-dimensional gap or interference (overlap) may occur between the mandibular branch and the mandibular body. Especially in the current dental surgery environment, there is no established interface for close continuity and linkage between the work of the orthodontist producing the bite splint and the work of the surgeon performing the maxillary osteotomy, The fact is that such a problem has not been solved sufficiently.

  On the other hand, in relation to the above-described problem, Patent Document 1 describes, “A method for supporting the placement of an implant on the osteotomy surface of a tibia in artificial knee joint replacement, X-ray image data and CT or MRI image data are acquired, and a three-dimensional simulation of mounting the implant is performed based on the acquired X-ray image data and CT or MRI image data and shape data of the implant to be mounted. "Featured artificial knee joint replacement support method" is described.

Patent Document 2 discloses that “a method of designing an implant applied to a bone body having a bone defect portion, and obtaining a plurality of tomographic data of the bone body based on measurement data of MRI (magnetic resonance image). A step of creating three-dimensional data of the bone body based on a plurality of the tomographic data, and a step of predicting a shape of the bone body to be in the bone defect portion, and a circumferential direction of the implant The implant design method is characterized in that at least a part of the bone body is designed so as to match the shape of the osteotomy surface of the bone body. "
JP 2004-8707 A JP 2004-57355 A

  However, the technique described in Patent Document 1 relates to surgery not related to dentistry or the oral cavity, and assists in mounting the implant on the osteotomy surface of the tibia in artificial joint replacement, as it is. Even if it is applied to maxillary and maxillary osteotomy for patients with dementia, a bite splint that achieves the normal positional relationship between the maxilla and mandible is obtained by taking into account the computer-aided interference and gaps between the osteotomy during surgery. I can't.

  The technique of Patent Document 2 is also related to surgery not related to the oral cavity as in Patent Document 1, and is a method of designing an implant to be applied to a bone body having a bone defect portion. Even when applied to the patient's upper and lower jaw osteotomy, a bite splint that achieves the normal positional relationship between the upper jaw and the lower jaw is obtained after taking into account the interference and gaps between the bone sections at the time of surgery by computer simulation in advance. Absent.

  That is, even with conventional techniques, in maxillary osteotomy for patients with jaw deformities, the upper and lower jaws are manipulated by an appropriate technique selected in consideration of computer-aided interference and gaps between bone sections at the time of surgery. It is difficult to realize a normal positional relationship with

  Therefore, the present invention has been made in view of the above problems, and in order to support the maxillomandibular osteotomy operation for jaw deformity patients, the interference and gaps between the bone sections at the time of surgery are calculated by computer simulation in advance. In view of the above, an object of the present invention is to provide a method for manufacturing a bite splint that can reliably set a normal positional relationship between an upper jaw and a lower jaw during an operation.

The present invention is a method of manufacturing a bite splint used to support maxillary osteotomy for jaw deformity patients,
(1) In a three-dimensional skull image created from skull tomography data of the skull of a jaw deformity patient , at least the upper dentition and the lower dentition between the upper jaw or the lower jaw included in the three-dimensional skull image Inserting a substantially rectangular parallelepiped object having a shape and dimensions including: obtaining an impression image of the upper and lower jaw occlusal surfaces, and then creating a virtual bite splint image based on the impression image;
(2) producing a byte splint based on the data of the virtual byte splint image;
It is the manufacturing method of the byte splint characterized by including these.

  According to the manufacturing method of the bite splint of the present invention having the steps as described above, the bite splint is created based on the three-dimensional simulation. It is possible to obtain a bite splint in which the normal positional relationship between the upper jaw and the lower jaw can be accurately set in consideration of interference and gaps between the sections by computer simulation.

It is process drawing of the manufacturing method of the bite splint of this invention. 3 is a diagram illustrating a three-dimensional skull image created in Example 1. FIG. FIG. 6 is a diagram illustrating a state in which a substantially rectangular parallelepiped object is inserted into the three-dimensional skull image in the first embodiment. 3 is a top view of a virtual byte splint image created in Embodiment 1. FIG. It is a figure which shows the trace of the cephalogram conventionally used.

  In the following, a preferred embodiment of the method for manufacturing a bite splint of the present invention will be described in the order of steps with reference to the drawings as appropriate. FIG. 1 is a process diagram of a method for manufacturing a bite splint according to the present invention.

  As shown in FIG. 1, in this embodiment, as a pre-process, a three-dimensional skull image is created from skull tomography data of the skull of a jaw deformity patient. At this time, preferably, the upper jaw and the lower jaw are set to normal positions in consideration of the interference and gap between the bone sections at the time of surgery by computer simulation in advance. Then, a substantially rectangular parallelepiped object is inserted between the upper jaw or the lower jaw from the three-dimensional skull image, an impression image of the upper and lower jaw occlusal surfaces is acquired, and a virtual bite splint image is created (step 1). A byte splint is created based on the image data (step 2).

pre-process:
First, in the manufacturing method of the bite splint of the present invention, a tomographic image of the skull of a jaw deformity patient is acquired, skull tomographic data is obtained, and a three-dimensional skull image is created therefrom.
Here, patients with jaw deformities generally have upper and lower teeth meshed together because the upper jaw or lower jaw extends too far forward, or conversely the jaw is small, and the symmetry of the upper and lower jaws is impaired. Refers to a patient having a symptom in which the upper and lower jaw occlusal surfaces are inclined with respect to the face-ear plane, or the face is asymmetrically distorted. In the present invention, it means a patient having the above symptoms to such an extent that he can undergo maxillary osteotomy.

  Further, the skull part includes various medical components, and the skull part of the jaw deformity patient in the present invention is a part of the normal skull, which is a target of the maxillary osteotomy for jaw deformity, that is, It refers to a portion including at least the maxilla, mandible and upper and lower teeth. That is, in the present invention, a tomographic image of the skull including at least the above-described part may be taken.

  The tomographic image of the cranium acquired in this pre-process is a two-dimensional photographic image, such as a CT (Computerized Tomography) image and an MRI (Magnetic Resonance Imaging) image. Among these, a CT image is preferable because a bone image with high accuracy can be obtained.

  In particular, when a CT image is taken as a tomographic image of the cranium, it can be taken using a conventionally known apparatus, but it is possible to acquire cranial tomographic data used in a subsequent process efficiently with high accuracy. From the viewpoint, for example, 16-row multi-slice helical CT (SOMATOM Sensation (trade name) manufactured by Siemens, slice width 0.31 mm) is preferably used.

  The slice width when taking a CT image is preferably 0.3 to 1.0 mm. This is because there is a problem that the data tends to be too large if it is less than 0.3 mm, and there is a problem that the accuracy of the three-dimensionally constructed image tends to be inferior if it exceeds 1.0 mm.

Next, in this pre-process, skull tomographic data is obtained from the tomographic image.
This cranial tomography data is two-dimensional data of the skull, and is preferably data of an effective method when constructing three-dimensional data in step 1 of the present invention. When a CT image is taken using the 16-row multi-slice helical CT, DICOM (Digital Imaging and Communications in Medicine) data can be obtained.

  In the pre-process, a three-dimensional skull image is created from the skull tomography data obtained above. The three-dimensional skull image is generated by converting the skull tomography data, which is two-dimensional data, into three-dimensional data using a conventionally known method, that is, a computer and software.

When the above-mentioned 16-column multi-slice helical CT is used as the skull tomography data, the DICOM-type skull tomography data is obtained. A 3D skull image can be constructed using Graphic's VGStudio Max 1.1 (trade name). In this case, DICOM data is converted into STL (Standard Template Library) three-dimensional data.
The two-dimensional data DICOM skull tomography data and the three-dimensional STL three-dimensional skull image data are both referred to as CAD (Computer Aided Design) data.

  Subsequently, in the pre-process of this embodiment, in the three-dimensional skull image, at least one of the maxillary bone image and the mandible image included in the three-dimensional skull image is cut, and the maxillary bone fragment image and the mandible Set a single image to a normal position. That is, this operation is performed on a computer screen as a three-dimensional cutting simulation.

  In this cutting simulation of the maxilla and mandible, the maxillary and mandibular occlusion, the gap and interference between the maxillary bone fragment and the maxilla, and the gap and interference between the mandibular body and the mandibular branch are considered, and the cut maxillary bone fragment image And / or determining the amount of movement of the mandibular fragment image. In this simulation, simulation software (for example, V-works manufactured by Cyber Med) operated with a mouse which is a normal computer device, a haptic device which is a haptic device, or the like can be used.

  In particular, it is possible to perform operations such as cutting of the maxillary and mandibular images, movement of the cut part of the maxillary bone fragments image, mandibular bone fragment images, joining, and deformation with a sensation similar to actual maxillary osteotomy. Therefore, it is preferable to use a haptic device (haptic device). Suitable examples of the haptic device include a FreeForm (trade name) system including PHANTOM (trade name) manufactured by SenSable Technologies Inc., USA.

  Here, as a method of cutting the maxillary image and the mandibular image in the three-dimensional skull image, a conventionally known method can be adopted, for example, maxillary division (Le Fort I), intraoral mandibular branch vertical division Surgery (IVRO), mandibular branch sagittal segmentation (SSRO), etc., can be performed to move the upper and lower jaw images to a normal position, and there is little interference and gaps between bone fragment images, and promptly after surgery A technique that can be expected to be cured can be evaluated and determined by simulation. Of course, two or more of these may be used in combination.

  In this embodiment, after cutting the upper jaw image and the lower jaw image, both are moved to a normal position and fixed. The normal position referred to here is an appropriate position parallel to the face-ear plane (image) by meshing the upper dentition image and the lower dentition image in the three-dimensional skull image. In other words, the cut upper jaw so that the upper dentition and the lower dentition are meshed and parallel to the face and ear plane, and there is little interference and gap between the bone fragments, so that rapid healing can be expected after surgery. Move and fix the image and lower jaw image.

Step 1:
In step 1 of the manufacturing method of the bite splint of the present embodiment, the three-dimensional skull image prepared in the preceding step is fixed to the normal position included in the three-dimensional skull image. A substantially rectangular parallelepiped object is inserted between the upper jaw image and the lower jaw image, an impression image of the upper and lower jaw occlusal surfaces is acquired, and a virtual bite splint image including the impression image is created. This process uses the FreeForm (trade name) system including VGStudio Max 1.1 (trade name) manufactured by Volume Graphic and PHANTOM (trade name) manufactured by SenSable Technologies Inc. Can be implemented.

  The substantially rectangular parallelepiped object inserted between the upper jaw image and the lower jaw image fixed at the normal position in this step is an impression image of the upper and lower jaw occlusal surfaces, that is, the upper dentition image meshed with the lower jaw image and the lower side This represents a virtual mold material used to mold a dentition image. And the substantially rectangular parallelepiped object which has the impression which took the shape comprises the virtual byte splint image in this invention.

  In order to obtain an impression image of the upper and lower jaw occlusal surface (image), first, a substantially rectangular parallelepiped object is inserted so as to cover the upper and lower dentition images together with the upper and lower jaw occlusal surface using the haptic device, The data is superimposed on the lower jaw image and upper and lower dentition image data. This operation is performed on the screen. Then, in the computer, a subtraction process for deleting upper and lower dentition image data overlapping the data of the substantially rectangular parallelepiped object may be performed.

  The shape and size of the substantially rectangular parallelepiped object is not particularly limited as long as it covers at least the upper and lower jaw occlusal surfaces of the patient with jaw deformity in the three-dimensional skull image. It is preferable to cover all the side dentition images. Those skilled in the art can appropriately adjust the shape and size as long as the object of the present invention is not impaired.

Step 2:
Finally, a byte splint is created based on the virtual byte splint image data (CAD data). Such a byte splint can be manufactured by a conventionally known method, for example, a CAM (Computer Aided Manufacturing) method.

  In the CAM method, for example, an optical modeling method, a thin plate lamination method, a melt deposition method, a powder fixing method, or the like can be used. Among them, it is preferable to use the melt lamination method (FDM) because an impression of a dentition having a complicated shape can be molded with high accuracy by a plastic material. This melt lamination method can be carried out using, for example, PRODIGY (trade name) manufactured by Stratasys Inc., and the conditions thereof are appropriately adjusted by those skilled in the art within a range not impairing the effects of the present invention. can do.

  However, the lamination thickness in the melt lamination method is preferably 0.1 to 0.3 mm. This is because if it is less than 0.1 mm, there is a problem that the processing time tends to take too much, and if it exceeds 0.3 mm, there is a problem that the accuracy tends to decrease.

  Moreover, as a material used in order to produce a bite splint in this process 2, the material used in order to produce the conventional bite splint and a mouthpiece can be used. For example, polyvinyl acetate, polyester, polyisobutylene, silicone, acrylonitrile-butadiene-styrene (ABS) copolymer, polyacrylic acid, polymethyl methacrylate, polyethyl methacrylate, vinyl acetate, natural rubber, salts and copolymers thereof Examples thereof include polymers and mixtures thereof.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these Examples at all.

Example 1
In this example, a bite splint used to support surgical correction for a patient with jaw deformity whose upper and lower jaws were deformed and the occlusal plane was inclined was manufactured. That is, a bite splint for a jaw deformity patient who needs to move the upper and lower jaws to set a normal position in osteotomy of the jaw was prepared.

  First, in the previous process, a CT image of the skull of a patient with jaw deformity with deformities in the upper and lower jaws was taken using a 16-row multi-slice helical CT (SOMATOM Sensation (trade name) manufactured by Siemens) and DICOM. Cranial tomography data of the method was obtained. The slice width of the CT image was 0.31 mm.

  Next, the skull tomography data was taken into a computer, and a three-dimensional skull image was constructed from the skull tomography data on the computer using VGStudio Max 1.1 (trade name) manufactured by Volume Graphic. In this case, DICOM data was converted into STL three-dimensional data. FIG. 2A shows the three-dimensional skull image created here. As shown in FIG. 2A, in this jaw deformity patient, it can be seen that the lower jaw is deformed to the right and the occlusal plane 2 is inclined with respect to the face-ear plane 1.

  Next, using a haptic device (FreeForm (trade name) system including PHANTOM (trade name) manufactured by SenSable Technologies Inc., USA), the upper jaw image included in the three-dimensional skull image is Le Fort I, and the lower jaw image is SSRO The upper and lower dentition images were moved to a normal position so that the upper and lower dentition images were parallel to and meshed with the face-ear plane, while taking into account the interference and gap between the mandibular branch image and the mandibular body image. FIG. 2B shows a three-dimensional skull image obtained by setting the positions of the upper jaw image and the lower jaw image to normal positions. As shown in FIG. 2B, the occlusal plane 3 of the jaw deformity patient is substantially parallel to the face-ear plane 1.

  Thereafter, as step 1 of the present invention, on the computer screen, the haptic device as shown in FIG. 3 between the upper jaw image and the lower jaw image set at normal positions among the three-dimensional skull images. A substantially rectangular parallelepiped object was inserted using. FIG. 3 is a diagram illustrating a state in which a substantially rectangular parallelepiped object 4 is inserted into a portion including the occlusal plane 3 of the three-dimensional skull image in which the upper jaw image and the lower jaw image are set at normal positions. The size of the substantially rectangular parallelepiped object 4 was adjusted so as to cover the entire occlusal plane 3 and also cover the upper and lower dentition images.

  Then, the computer performs a subtraction process to delete upper and lower dentition image data overlapping with the data of the substantially rectangular parallelepiped object, obtains an impression image of the upper and lower jaw occlusal surfaces, and creates a virtual bite splint image having the impression image did. FIG. 4 is a top view showing the upper part 5 and the lower part 6 including the upper and lower jaw occlusal surfaces of the virtual bite splint image created in this step.

  Next, as step 2 of the present invention, a byte splint was produced based on the data of the virtual byte splint image by a melt lamination method using PRODIGY (trade name) manufactured by Stratasys Inc. The bite splint obtained in this example was useful for setting the normal positions of the maxilla and mandible of patients with jaw deformities and could be suitably used to support the maxillary and maxillary osteotomy.

Example 2
In this example, a bite splint used to support surgical correction for a patient with jaw deformity whose upper and lower jaws were deformed and the occlusal plane was inclined was manufactured. That is, a bite splint for a jaw deformity patient who needs to move the upper and lower jaws to set a normal position in osteotomy of the jaw was prepared. Specifically, a bite splint was produced in the same manner as in Example 1.

  The bite splint obtained in this example is useful for setting the normal position of the maxilla and mandible of the patient with jaw deformity in consideration of the interference and gap between the mandibular branch and mandible by computer simulation. It could be suitably used to support a cutting operation.

  According to the manufacturing method of the bite splint of the present invention, when the upper and lower jaws of a jaw deformity patient are returned to a normal position, the three-dimensional generated between the maxillary bone fragment and the maxilla and between the mandibular branch and the mandibular body. It is possible to select and determine a surgical method and an incision part with a gap and interference (overlapping) as small as possible by simulation. Based on the positions of the upper and lower jaws corrected by the simulation, the bite splint is CADed, and the bite splint used in actual surgery can be manufactured by the CAM using the data. This bite print is created on the basis of a three-dimensional computer simulation, and is particularly effective for supporting a surgical correction operation (upper and lower jaw osteotomy) for jaw deformity patients.

1 face ear plane 2, 3 upper and lower jaw occlusal plane 4 substantially rectangular parallelepiped object 5 upper part of virtual byte splint image 6 lower part of virtual byte splint image

Claims (1)

A method for manufacturing a bite splint used to support osteotomy for maxillary and mandibular patients,
(1) In a three-dimensional skull image created from skull tomography data of the skull of a jaw deformity patient , at least the upper dentition and the lower dentition between the upper jaw or the lower jaw included in the three-dimensional skull image Inserting a substantially rectangular parallelepiped object having a shape and dimensions including: obtaining an impression image of the upper and lower jaw occlusal surfaces, and then creating a virtual bite splint image based on the impression image;
(2) producing a byte splint based on the data of the virtual byte splint image;
A method for producing a bite splint, comprising:

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