WO2021090760A1 - Method for obtaining correction target skull shape and method for generating plagiocephaly correction target data - Google Patents

Abstract

This method for obtaining a correction target skull shape comprises: a scan data reading step for reading three-dimensional scan data indicating the skull shape of a patient; a plagiocephaly ideal correction data generation step for generating plagiocephaly ideal correction data indicating the plagiocephaly ideal correction shape of the patient, on the basis of the three-dimensional scan data; a plagiocephaly correction rate designation step for specifying the plagiocephaly correction rate in accordance with the degree of plagiocephaly; and a plagiocephaly correction target data generation step for generating plagiocephaly correction target data indicating a plagiocephaly correction target skull shape on the basis of the plagiocephaly ideal correction data and the plagiocephaly correction rate.　Further, a method for generating orthodontic helmet production data for producing an orthodontic helmet for correcting deformed skull with a three-dimensional printer comprises: an input step for importing correction target skull shape data indicating the correction target skull shape into three-dimensional CAD software and generating mesh data indicating a correction target skull surface shape; an offset step for offsetting mesh data by a predetermined amount in an expansion direction; a deletion step for deleting unnecessary parts from the mesh data; a thickness imparting step for imparting a predetermined thickness to the mesh data; and an output step for outputting mesh data in stl format, which is offset in the expansion direction, has unnecessary parts removed, and is given a thickness.

Description

How to find the correction target skull shape and how to generate the correction helmet production data

The present invention uses a three-dimensional printer to manufacture a method for obtaining a correction target skull shape for correcting a deformed skull, that is, a plagiocephaly and / or a brachycephaly, and a correction helmet for correcting a deformed skull based on the correction target skull shape. Regarding how to generate corrective helmet manufacturing data for

Patent Document 1 below discloses an orthodontic helmet for correcting a deformed skull of a patient (usually an infant). Such an orthodontic helmet recognizes the skull shape of an individual patient, determines how to correct it according to the skull deformation of each patient, in other words, obtains the correction target skull shape, and obtains such a correction target skull shape. It is important to manufacture according to. On the other hand, Patent Document 2 below conceptually discloses that ideal skull shape data is obtained based on three-dimensional scan data showing the skull shape of an infant, and a skull deformation correction helmet is manufactured based on the ideal skull shape data. ing.

Japanese Patent No. 6333514 U.S. Pat. No. 6,340,353

Thus, although Patent Document 1 discloses that a straightening helmet is manufactured by a three-dimensional printer, it is completely described what kind of data is input to the three-dimensional printer to manufacture the straightening helmet. Absent. On the other hand, in Patent Document 2, as described above, it is conceptual that the ideal skull shape data is obtained based on the three-dimensional scan data indicating the skull shape of the patient, and the skull deformation correction helmet is manufactured based on the ideal skull shape data. However, there is no specific description of how to obtain ideal cranial shape data. In addition, regarding the disclosure of Patent Document 2, the following facts should be noted. That is, the ideal skull shape data is obtained, and the skull deformation correction helmet is manufactured based on the ideal skull shape. However, according to the experience of the present inventors, for example, the degree of oblique head and / or short head is considerably large. In some cases, it has been found that it is practically impossible to correct to the ideal cranial shape, and it is not always appropriate to apply a cranial deformity correction helmet for correcting to the ideal cranial shape to the target patient.

The present invention has been made in view of the above facts, the first technical challenge of which is to create an orthodontic helmet that is optimally applied to individual patients depending on the degree of plagiocephaly and / or brachycephaly. To provide a new and improved method for determining the target cranial shape for plagiocephaly and / or brachycephaly correction.

The second technical problem of the present invention is the correction target skull shape data of the patient (the correction target skull data does not always match the ideal skull shape data, for example, in the case of an excessively deformed skull, the ideal skull shape is obtained. Providing a new and improved method of adding the required processing to (it is not always appropriate to be a corrective helmet) and supplying it to a three-dimensional printer to generate corrective helmet production data that enables the production of the required corrective helmet. It is to be.

As a result of diligent studies, the present inventors have obtained plagiocephaly and / or brachycephaly ideal correction data for ideally correcting the brachycephaly and / or brachycephaly based on three-dimensional scan data showing the shape of the patient's skull. Generate and further specify the plagiocephaly and / or brachycephaly correction rate according to the degree of plagiocephaly and / or brachycephaly, and the plagiocephaly and / or brachycephaly ideal correction data and the brachycephaly and / or brachycephaly correction rate. It was found that the first technical problem can be achieved by generating the brachycephaly and / or brachycephaly correction target data indicating the cranial shape based on the above.

That is, according to the first aspect of the present invention, as a method of achieving the first technical problem,
The scan data reading process that reads the three-dimensional scan data that shows the shape of the patient's skull,
Based on the three-dimensional scan data, an oblique head ideal correction data generation step of generating oblique head ideal correction data indicating a patient's oblique head ideal correction shape, and an oblique head ideal correction data generation step.
The process of specifying the plagiocephaly correction rate according to the degree of plagiocephaly, and the process of specifying the plagiocephaly correction rate.
A plagiocephaly correction target data generation process for generating plagiocephaly correction target data indicating a cranial shape based on the plagiocephaly ideal correction data and the plagiocephaly correction rate.
Provided is a method for determining a correction target cranial shape, which comprises.

According to the second aspect of the present invention, as a method of achieving the first technical problem,
The scan data reading process that reads the three-dimensional scan data that shows the shape of the patient's skull,
Based on the three-dimensional scan data, a brachycephaly ideal correction data generation step of generating brachycephaly ideal correction data showing a patient's brachycephaly ideal correction shape, and a process of generating brachycephaly ideal correction data.
The process of specifying the brachycephaly correction rate according to the degree of brachycephaly and the process of specifying the brachycephaly correction rate,
Brachycephaly correction target data generation process for generating short head correction target data indicating the shape of the brachycephaly correction target based on the ideal correction data for the short head and the correction rate for the short head.
Provided is a method for determining a correction target cranial shape, which comprises.

According to the third aspect of the present invention, as a method for achieving the first technical problem,
The scan data reading process that reads the three-dimensional scan data that shows the shape of the patient's skull,
Based on the three-dimensional scan data, an oblique head ideal correction data generation step of generating oblique head ideal correction data indicating a patient's oblique head ideal correction shape, and an oblique head ideal correction data generation step.
The process of specifying the plagiocephaly correction rate, which specifies the correction rate according to the degree of plagiocephaly,
A plagiocephaly correction target data generation step of generating a plagiocephaly correction target data indicating a cranial shape based on the plagiocephaly ideal correction data and the correction rate.
Based on the three-dimensional scan data, a process of generating brachycephaly ideal correction data that generates brachycephaly ideal correction data indicating a patient's brachycephaly ideal correction shape, and a process of generating brachycephaly ideal correction data.
The process of specifying the brachycephaly correction rate, which specifies the correction rate according to the degree of brachycephaly,
Brachycephaly correction target data generation process for generating short head correction target data indicating the shape of the short head correction target skull based on the ideal correction data for the short head and the correction rate, and a process for generating the target data for the short head correction.
Provided is a method for determining a correction target cranial shape, which comprises.

The plagiocephaly ideal correction data generation step is
To set three reference points based on the three-dimensional scan data and set a reference plane including the three reference points.
To set a plurality of planes parallel to the reference plane and select one specific plane from the set plurality of planes.
Finding four intersections of two inclined lines and a skull shape that are inclined at predetermined angles in opposite directions to the center line extending in the anteroposterior direction in the specific plane.
Is preferable to include
The brachycephaly ideal correction data generation step is
Set a horizontal centerline that extends horizontally to the center of the skull posteriorly from the selion and a width line that passes through both Tradion landmarks.
To set three reference points based on the three-dimensional scan data and set a reference plane including the three reference points.
To set a plurality of planes parallel to the reference plane and select one specific plane from the set plurality of planes.
The horizontal center line and a straight line in the width direction passing through both tradion landmarks are projected onto the specific plane, and two anteroposterior intersections of the horizontal center line and the cranial shape projected on the specific plane are obtained and projected. Finding the two widthwise intersections of the width line and the cranial shape,
Obtaining the length PLx between the two front-rear intersections and the length PLy between the two widthwise intersections, and calculating PLx / PLy.
Is preferable to include
It is preferable that the three reference points are a serion and two tradion landmarks.
The plurality of planes preferably include an apex plane that passes through the apex of the skull and is parallel to the reference plane, and intermediate planes that are evenly spaced between the reference plane and the apex plane.
To assist in the designation of the plagiocephaly and / or brachycephaly correction rate, the arbitrary plagiocephaly and / or brachycephaly correction rate is based on the plagiocephaly and / or brachycephaly ideal correction data and any plagiocephaly and / or brachycephaly correction rate. And / or it is preferable to include a display step of displaying the cranial shape corrected by the brachycephaly correction rate.
Find the length Lx from the selion to the intersection of the horizontal center line and the posterior surface of the skull and the length Ly of both tradion landmark rods, calculate Lx / Ly, and determine whether brachycephaly correction is necessary. It is desirable to include determining whether or not.

Furthermore, as a result of diligent studies, the present inventors have incorporated the correction target skull shape data indicating the correction target skull shape into appropriate three-dimensional CAD (Computer Aided Design) software, and by subjecting the data to appropriate processing. We have found that the above main technical issues can be achieved.

That is, according to the present invention, as a method of achieving the above-mentioned main technical problem,
Using a method to generate orthodontic helmet production data for producing an orthodontic helmet for correcting a deformed skull with a three-dimensional printer,
Correction target Cranial shape showing correction target Cranial shape data is imported into 3D CAD software, and a mesh data showing correction target skull surface shape is generated.
An offset step of offsetting the mesh data by a predetermined amount in the expansion direction,
A deletion process that deletes unnecessary parts from the mesh data,
A thickness imparting step of imparting a predetermined amount of thickness to the mesh data, and
An output process that outputs the mesh data that is offset in the expansion direction, has unnecessary parts removed, and is given a thickness.
A method is provided characterized by including.

Preferably, the deletion step is carried out after the offset step and the thickness imparting step is carried out after the removal step. After the input step and before the offset step, a hollow curve is formed by hollowing out the left and right pinna based on the pinna trace curve that traces the left and right pinna, and the left and right hollow curves are connected to form a hollow surface. It is preferable to include an auricle treatment step of forming, hollowing out the mesh data with the hollowed out surface, and further filling the cutout portion with a mesh defining a surface to be smoothly connected to the periphery. The removal step offsets the auricle trace curve by a predetermined amount in the enlargement direction, forms a front cut surface based on the offset auricle trace and serion, and cuts by the front cut surface, a predetermined collar height. It is preferable to include cutting downward from the auricle, rounding the sharp portion generated by the cutting, generating a cut cylinder which is a cylinder centered on the center point of the top surface of the skull, and cutting with the cut cylinder. It is desirable to include a sideburn extension step of adding a sideburn extension mesh that extends the sideburns portion downward by a predetermined amount after the deletion step and before the output step. Preferably, after the cutting step and before the output step, a slit extending continuously from the upper end edge to the lower end edge is formed adjacent to the sideburns portion, and the sharpness generated by forming the slit. Includes a slit forming step to round the sideburns. A ventilation hole forming step of forming a plurality of ventilation holes at intervals in a main region excluding an outer peripheral region having a predetermined width from the outer peripheral edge of the mesh data is included after the deletion step and before the output step. Is preferable. After the slit forming step and before the output step, a solid round bar having a predetermined diameter extending continuously is formed along the outer peripheral edge of the mesh data except for the portion where the slit exists. Then, it is preferable to include a round bar joining step of joining the round bar to the mesh data and rounding the joint portion. Prior to the output step, it is convenient to include a display forming step of forming a display containing characters and / or symbols in a predetermined portion of the mesh data. It is convenient to output the mesh data in stl format in the output process.

In the first, second and third aspects of the present invention, the brachycephaly and / or brachycephaly ideal correction data for ideally correcting the brachycephaly and / or brachycephaly of the patient is generated. In addition to doing so, specify the correction rate according to the degree of brachycephaly and / or brachycephaly, and based on the ideal brachycephaly and / or brachycephaly correction data and brachycephaly correction target. Creating an optimal cranial deformity correction helmet to be applied to individual patients depending on the degree of plagiocephaly and / or brachycephaly because it generates brachycephaly and / or brachycephaly target data showing the cranial shape. Brachycephaly and / or brachycephaly correction target data indicating the cranial shape is obtained.

Any oblique in a particular plane based on the ideal plagiocephaly and / or brachycephaly correction data and any plagiocephaly and / or brachycephaly correction rate to aid in the designation of plagiocephaly and / or brachycephaly correction rate. By observing any plagiocephaly and / or brachycephaly-corrected cranial shape in a particular plane, including a display step of displaying the head and / or brachycephaly-corrected cranial shape. The appropriate plagiocephaly and / or brachycephaly correction rate can be specified easily and quickly enough.

In the fourth aspect of the present invention, the viewer's correction target cranial shape data is taken into the three-dimensional CAD software, the required processing is performed, and the data is supplied to the three-dimensional printer to manufacture the required correction helmet. Corrective helmet production data is generated.

FIG. 6 is a simplified diagram showing a system used to determine a correction target skull shape according to the present invention. A flowchart showing a preferred embodiment of the method of the present invention for obtaining a correction target skull shape for correcting an oblique head and a short head. A slope image displaying three-dimensional scan data showing the shape of the patient's skull. The schematic diagram which shows an example of the shape of the reference plane in the shape of a patient's skull. The schematic view which shows the reference plane, the parietal plane and a plurality of intermediate planes in the cranial shape of a patient. The schematic diagram which shows the mode which generates the plagiocephaly correction ideal data in the selected specific plane. The schematic diagram for demonstrating the determination of the necessity of brachycephaly correction. The schematic diagram which shows the generation style of the brachycephaly correction ideal data in the selected specific plane. Part of a flowchart showing a preferred embodiment of the method of the present invention, which generates orthodontic helmet fabrication data for straightening a deformed skull with a three-dimensional printer. A part of a flowchart showing a preferred embodiment of the method of the present invention for generating orthodontic helmet fabrication data for correcting a deformed cranial by a three-dimensional printer. Correction target Schematic diagram of mesh data showing the surface shape of the skull. The schematic diagram which shows the trace curve of auricle. The schematic diagram which shows the hollowed-out surface formed based on the trace curve of FIG. FIG. 6 is a schematic view showing a state of being hollowed out by the hollowed out surface shown in FIG. FIG. 6 is a schematic view showing complementary mesh data in which a hollow portion illustrated in FIG. 13 is filled with a mesh defining a smooth surface. The schematic diagram which shows the offset mesh data. Schematic diagram showing the front cut surface. The schematic diagram which shows the front cut mesh data. The schematic diagram which shows the predetermined height plane. The schematic diagram which shows the lower cut mesh data. The schematic diagram which shows the cut cylinder. The schematic diagram which shows the top surface hollowed-out mesh data. The schematic diagram which shows the sideburns extension mesh data. The schematic diagram which shows the slit formation mesh data. The schematic diagram which shows the ventilation hole generated in the mesh data. The schematic diagram which shows the mesh data for manufacturing the orthodontic helmet.

First, a preferred embodiment of the method for obtaining a correction target skull shape for correcting a plagiocephaly and / or a brachycephaly of the present invention will be described in detail with reference to the attached drawings.

FIG. 1 illustrates a system for carrying out the method of determining the correction target skull shape of the present invention. This system scans the central processing means 2 composed of an appropriate computer, the image display means 4 connected to the central processing means 2, and the patient's skull to generate three-dimensional data indicating the shape of the patient's skull. For the purpose, the scanning means 6 which itself may be in a well-known form is included.

FIG. 2 shows a flowchart for obtaining the plagiocephaly correction target data and the brachycephaly correction target data, and steps n-1 to n-9 in FIG. 2 relate to the plagiocephaly correction target data in steps n-10. To n-18 relate to brachycephaly correction target data. Explaining with reference to FIG. 2, in step n-1 (scan data reading step), a three-dimensional scan showing the shape of the patient's skull, which is generated by scanning the patient's skull by the scanning means 6. The data is read into the central processing means 2. Next, in step n-2 (reference three-point setting step), the reference three points are set on the patient's skull shape image as illustrated in FIG. 3, which is displayed on the image display means 4 based on the three-dimensional scan data. Set manually. As shown in FIG. 3, it is convenient that the three reference points are the serion P1 existing in the center between the eyes and the two tradion landmarks P2 and P3 which are specific points in the binaural earlobe. In step n-3 (reference plane setting step), the reference plane PL0 including the above three points is set. Next, in step n-4 (center line and inclination line setting step), as shown in FIG. 4, the center line CL extending in the front-rear direction on the reference plane PL0 and the center line CL are in phase with each other. Two inclined lines IL1 and IL2 that are inclined by a predetermined angle α in the opposite direction are drawn. The predetermined angle α may be, for example, 30 degrees. In step n-5 (plural plane setting and center line and inclined line duplication step), a plurality of planes parallel to the reference plane are set. As shown in FIG. 5, such a plurality of planes are, for example, evenly distributed between the apex plane PL10 passing through the cranial apex of the patient and parallel to the reference plane PL0, and the apex plane and the reference plane. Nine intermediate planes PL1 to PL9 that pass through the points and are parallel to the reference plane PL0 may be used. In step n-5, the center line CL and the two inclined lines IL1 and IL2 drawn on the reference plane PL0 are further projected and duplicated on each of the apex plane PL10 and the intermediate planes PL1 to PL9.

After that, in step n-6 (specific plane selection step), one of the intermediate planes PL1 to PL9 is selected as the specific plane. For this specific plane, it is desirable to select an intermediate plane in which the situation of the oblique head is simply displayed, judging from the slope image shown in FIG. 3, and usually, it is the third intermediate plane counted from the bottom. That is, the intermediate plane PL3 can be selected. Further, as shown in FIG. 6, in the selected specific plane (for example, the intermediate plane PL3), the skull shape in the intermediate plane PL3 and the two inclined lines IL1 and IL2 duplicated in the intermediate plane PL3 are four. Intersections C1, C2, C3 and C4 are acquired. Next, in step n-7 (plagiocephaly setting step), the uneven relationship between the intersection C1 and the intersection C2 on the anterior side of the skull, and in the case shown in FIG. 6, the intersection C1 is L1 with respect to the center rather than the tolerance point C2. It is recognized that the intersection C3 and the intersection C4 are retracted on the outside of the skull, and in the case shown in FIG. 6, the intersection C3 is retracted from the center by L2 from the tolerance point C4. Is certified. In step n-8 (plagiocephaly ideal correction data generation step), plagiocephaly ideal correction data, which is a shape in which the plagiocephaly is ideally corrected, is generated, and an ideal cranial shape IS1 in which the plagiocephaly is ideally corrected is obtained. Be done. More specifically, data on the ideal skull shape IS1 obtained by displacing the intersection C1 anteriorly and laterally by L1 with respect to the center and displacing the intersection C3 posteriorly and laterally by L2, that is, oblique head ideal correction data is generated.

Therefore, according to the experience of the present inventors, when the degree of obliqueness is particularly large, if the correction is made to the ideal shape, a phenomenon such as correction failure or inability to correct occurs, and the correction is made to the ideal shape. It turns out that the production of orthodontic helmets is not always appropriate. Therefore, in the present invention, in step n-9 (correction target skull data generation step), correction target skull data is generated based on an appropriate plagiocephaly correction rate R1. More specifically, preferably, when correcting with an arbitrary plagiocephaly correction rate R based on the ideal skull shape IS1 generated in step n-8 (that is, the intersection C1 is not displaced by L1 but displaced by L1 × R). Then, the corrected skull shape at the intersection C3 is displaced by L2 × R) is appropriately displayed as an image, and the plagiocephaly correction rate R is specified with reference to the image display. In other words, in order to assist the designation of the oblique head correction rate R1, the corrected skull shape on the intermediate surface PL3 when correcting with an arbitrary oblique head correction rate R is appropriately displayed as an image. Then, the plagiocephaly ideal correction data is corrected according to the designated plagiocephaly correction rate R1 to generate plagiocephaly target correction data when the plagiocephaly is corrected with an appropriate plagiocephaly correction rate R (such plagiocephaly target correction data). Is used to make orthodontic helmets). If desired, the correction rate R of L1 and the correction rate R of L2 may be set separately instead of being the same. That is, R1 can be adopted as the correction rate of L1 and R2 can act as the correction rate of L2 (R1 ≠ R2).

In step n-10 (horizontal centerline setting step), as shown in FIG. 7, a horizontal centerline HCL extending horizontally from Selion P1 (also referred to in FIG. 3) rearward through the center of the skull. Set and obtain the intersection C5 between this horizontal centerline HCL and the posterior surface of the skull. Next, in step n-11 (width line setting), a width line WL connecting the Tradion landmarks P2 and P3 (see also FIG. 3) is set. In step n-12 (calculation of skull length and width), the distance Lx between the serion P1 at the horizontal center line HCL, the horizontal center line HCL, and the intersection C5 between the posterior surface of the skull is calculated, and both at the width line WL. The distance Ly between the tradion landmarks P2 and P3 is calculated. Next, in step n-13 (determination of the need for brachycephaly correction), Lx / Ly is calculated to determine whether or not brachycephaly correction is necessary. Normally, the ideal value of Lx / Ly is about 1.15 (ideal ratio 1.15 to 1.00). For example, when Lx / Ly is 0.95 or less, it is determined that brachycephaly correction is necessary. To do. Then, when it is determined that the brachycephaly correction is unnecessary, the process proceeds to step n-14 (data output step), and the oblique head target correction data generated in the above step n-9 is used for helmet production. Output as data. On the other hand, if it is determined that brachycephaly correction is necessary, the process proceeds to step n-15 (horizontal center line and width line duplication step).

In step n-15 (horizontal center line and width line duplication step), the horizontal center line is formed on the reference plane PL0, the nine intermediate planes PL1 to PL9 set in step n-5, and the top plane PL10, respectively. HCL and width line WL are projected and duplicated. Next, in step n-16 (acquisition of cranial length and width in a specific plane), one of the nine intermediate planes PL1 to PL9 is selected as the specific plane. As for this specific plane, it is desirable to select an intermediate plane in which the situation of the brachycephaly is simply displayed, judging from the slope image shown in FIG. 3, as in the case of the oblique head correction, and it is usually downward. The third intermediate plane, that is, the intermediate plane PL3 can be selected counting from. Then, as shown in FIG. 8, the horizontal center line HCL duplicated in the selected specific plane and the anteroposterior intersection C6 and C7 of the skull shape are acquired, and the duplicated width line WL and the skull shape are also obtained. Width direction intersections C8 and C9 are acquired. It is convenient that the skull shape used in this step n-16 is based on the oblique target correction data generated in the above step n-9 (that is, the skull shape subjected to the oblique target correction). .. In step n-17 (short head ideal correction data generation step), the cranial length (that is, the distance between the intersection C6 and the intersection C7) PLy and the cranial width (that is, the distance between the intersection C8 and the intersection C9) Plx And are calculated. Then, in order to achieve the specified ideal value of PLx / Ply (usually about 1.15), the length IL3 for moving the intersection C7 to the rear of the skull is calculated, and the brachycephaly is ideally corrected. A certain brachycephaly ideal correction data is generated, and an ideal skull shape IS2 in which the brachycephaly is ideally corrected is obtained. Further, as in the case of plagiocephaly correction, in step n-18 (correction target skull data generation step), correction target skull data is generated based on an appropriate brachycephaly correction rate R2. More specifically, when the brachycephaly correction rate R is corrected based on the ideal skull shape IS2 generated in step n-17 (that is, when the intersection C7 is displaced by IL3 × R instead of being displaced by IL3). ) Is appropriately displayed as an image of the corrected skull shape, and the brachycephaly correction rate R is specified with reference to the image display. In other words, in order to assist in the designation of the brachycephaly correction rate R2, the shape of the corrected skull when the brachycephaly correction rate R is corrected is appropriately displayed as an image. Then, the brachycephaly ideal correction data is corrected by the designated plagiocephaly correction rate R2, and the brachycephaly target correction data when the brachycephaly is corrected by the appropriate brachycephaly correction rate R2 is generated (such plagiocephaly target correction data). Is used to make orthodontic helmets). In step n-17, the skull shape based on the oblique target correction data generated in step n-9 is used. Therefore, the data generated in step n-18 is the oblique target correction and the brachycephaly target. Cranial target correction data considering both correction and correction. In step n-19, the cranial target correction data generated in step n-18 is output as data for helmet production.

The target correction data output in steps n-14 and 19 above is skull shape data in a specific plane, that is, two-dimensional data. In order to obtain the correction target cranial shape based on such two-dimensional data, two-dimensional using the "Grasshopper" function in 3D CAD, which is commercially available under the trade name "Rhinoceros", based on the required algorithm, for example. The data may be converted into three-dimensional data. If desired, the cranial target correction data generated in the steps n-9 and n-18 is converted into three-dimensional data prior to outputting the target correction data in the steps n-14 and n-19. It is also possible to convert and output the target correction data as three-dimensional data in the step n-14 and the step n-19.

Although the preferred embodiment of the method for obtaining the correction target skull shape configured according to the present invention has been described in detail with reference to the accompanying drawings, the present invention is not limited to such an embodiment and is the scope of the present invention. It is not necessary to say that various modifications and corrections can be made without deviating from.

For example, in the above-described embodiment, the skull shape with the oblique head target correction generated in step n-9 is used in step n-17, but if desired, the three-dimensional scan data is used in step n-17. It is also possible to use the cranial shape in a specific plane generated based on. In this case, in the additional step, the target correction skull shape is obtained by adding up the oblique head target correction data generated in step n-9 and the brachycephaly target correction data generated in step n-18. Can be done.

Further, in the above-described embodiment, only the target correction data on one specific plane is generated, but if necessary, the target correction data on a plurality of specific planes is generated and corrected based on these data. It is also possible to obtain the target cranial shape.

Further, in the above-described embodiment, the oblique head target formation data and the brachycephaly target correction data are generated as needed, but only the oblique target correction data is generated (in this case, steps n-10 to n-10 to 13 and steps n-15 to 19 are omitted) or only the brachycephaly target correction data is generated (in this case, steps n-2, n-4 and steps n-5 to 9 can be omitted). You can also do it.

Next, a preferred embodiment of the method of the present invention for generating correction helmet manufacturing data for correcting a deformed skull by a three-dimensional printer will be described in more detail with reference to the attached drawings.

Explaining with reference to the flowchart shown in FIG. 9, in step n-1, the correction target skull shape data indicating the correction target skull shape, preferably the method as described above with reference to FIGS. 1 to 8, is used. The obtained correction target skull shape data is incorporated into the three-dimensional CAD software installed in the computer, and mesh data 2 indicating the correction target skull shape is generated (input step). As the three-dimensional CAD software, the "Grasshopper" function in the three-dimensional CAD software sold under the above-mentioned trade name "Rhinoceros" can be preferably used. FIG. 10 schematically shows the target corrected skull shape shown by the generated mesh data 3. In step n-1, information indicating the center point of the top surface of the skull (indicated by triangle A in FIG. 10) and information indicating the height of the serion (indicated by triangle B in FIG. 10) are also taken in together with the mesh data. (The use of this information, i.e. triangles A and B, will be mentioned further later).

In step n-2, the left and right pinna are traced to generate the pinna trace curve 5 (FIG. 11). Next, in step n-3, as shown in FIG. 12, a hollow curve (closed endless curve) for hollowing out the left and right pinna is generated based on the pinna trace curve 5, and the left and right hollow curves are formed. The hollow surface 7 is connected to generate a hollow surface 7, and the mesh data 3 is hollowed out by the hollow surface 7 (FIG. 13). After that, in step n-4, the portion 8 hollowed out by the hollowed out surface 7 is supplemented with a mesh 10 that defines a surface to be smoothly connected to the periphery to form the supplementary mesh data 12 (FIG. 14). The processing in steps n-2 to n-4 is to avoid complicating the subsequent processing due to the presence of the protruding auricle.

Next, in step n-5, the compensation mesh data 12 is offset by a predetermined amount in the expansion direction. Enter the offset amount manually. FIG. 15 shows the offset mesh data 14 after offsetting, and the shape shown in FIG. 15 is enlarged by a predetermined amount with respect to the shape shown in FIG. As disclosed in Patent Document 1, the main body (that is, the shell) of the straightening helmet is conveniently molded from an appropriate synthetic resin by a powder sintering lamination method using a three-dimensional printer, but is thus molded. It is desirable that a liner formed of a foamed synthetic resin or the like is disposed on the inner surface of the straightening helmet. The offset in step n-5 takes into account the thickness of the liner disposed on the inner surface of the body of the orthodontic helmet. The offset amount is preferably a value somewhat smaller than the liner thickness and is manually entered.

On the other hand, in step n-6, the auricle trace curve 5 generated in step n-2 is offset by a predetermined amount in the expansion direction. Enter the offset amount manually. Then, in step n-7, as illustrated in FIG. 16, the ear is preferably offset based on the offset pinna trace curve and the serion captured in step n-1 (triangle B in FIG. 10). The auricle trace curve and the horizontal plane passing through the selion are combined to generate the front cut surface 16. Then, in step n-8, the offset mesh data 14 is cut out by the front cut surface 16. FIG. 17 shows the front cut mesh data 18 formed by cutting the offset mesh data 14 on the front cut surface 16. In step n-9, as shown in FIGS. 18 and 19, a portion below the horizontal plane 20 passing through the predetermined collar height in the front cut mesh data 18 is cut to form the lower cut mesh data 22. The horizontal plane 20 having a predetermined height is appropriately set based on the target correction skull shape and manually input. In step n-10, the sharp edges generated by the cuts in steps n-8 and n-9 above in the lower cut mesh data 22 are rounded. Then, in step n-11, as shown in FIGS. 20 and 21, a cylinder having a diameter d centered on the center point of the apical surface (see triangle A in FIG. 10) in the target corrected skull shape, preferably. A cut cylinder 24 that is inclined backward at a predetermined inclination angle α is generated downward, and the central portion of the top surface of the skull that is not subject to deformation cranial correction is hollowed out by the cut cylinder 24 to generate an opening 26, and the top surface hollowed out mesh data. 28 is formed. The diameter d may be about 10 cm. The inclination angle α is appropriately set based on the target correction skull shape and manually input. Thus, the steps n-6 to n-10 constitute a deletion step of deleting an unnecessary portion from the offset mesh data 14. If desired, the steps n-5 (mesh offset step) can also be performed after the steps n-6 to n-10 (deletion step).

In step n-12, the sideburns portion is tilted downward, and if necessary, forward or backward by a predetermined angle β, and is extended by a predetermined amount to generate sideburns extension mesh data 30 (sideburns extension step). ). The downward extension amount X and the inclination angle β of the sideburns portion are appropriately set according to the target correction skull shape and manually input. This extension of sideburns helps stabilize the wearing of helmets worn by infants. Next, in step n-13, a predetermined thickness t is imparted to the sideburns extension mesh data 30 (FIG. 22) (thickness imparting step). The thickness t corresponding to the thickness of the manufactured orthodontic helmet body (shell) may be about 3.0 mm, and is manually input. Then, in step n-14, a slit 32 extending continuously from the upper end to the lower end adjacent to the trailing edge of the sideburns was formed, and then in step n-15, the sharp point generated by the formation of the slit 32 was formed. Round the part (slit forming process). Thus, the mesh data 34 to which the thickness is added and the slit 32 is formed is formed.

In step n-16, as shown in FIG. 24, a plurality of ventilation holes 36 are generated at predetermined intervals in a region about 10 to 20 mm inside from the outer peripheral edge of the mesh data 34. (Vent hole forming process). The number, arrangement, shape and dimensions of the ventilation holes 36 are appropriately set and manually input.

On the other hand, in step n-17, the outer peripheral edge of the mesh data 34 is extracted. Then, in step n-18, the outer peripheral edge of the opening 26 formed on the top surface is continuously extended except for the portion of the slit 32, and the other (that is, the opening) of the mesh data 34. The length of the outer peripheral edge (excluding the outer peripheral edge of 26) extending continuously except for the portion of the slit 32 is calculated. At this time, the interval of the interrupted portion in the slit 32 portion is appropriately selected and manually input. In step n-19, two solid round bars 38 (see FIG. 25) having the length calculated in step n-18 are formed. The diameter of the solid round bar 38 constituting the thick-walled reinforcing portion for reinforcing the outer peripheral edge of the straightening helmet may be about 6 mm. Next, in step n-20, the mesh data 34 is provided with the outer peripheral edge of the opening 26 formed on the top surface of one solid round bar 38 so as to continuously extend except for the portion of the slit 32. The other solid round bar 38 is joined so that the other outer peripheral edge of the mesh data 34 (that is, excluding the outer peripheral edge of the opening 26) is continuously extended except for the portion of the slit 32. Combined with mesh data 34. In step n-21, the joint portion of the solid round bar 38 is smoothed so as to be smoothly continuous. Thus, the mesh data 40 for manufacturing the orthodontic helmet as shown in FIG. 25 is formed. The steps n-17 to n-21 constitute a round bar joining step.

In the illustrated embodiment, further, in step n-22, a display (not shown) containing ID data of the orthodontic helmet and / or characters and / or symbols indicating an appropriate trademark is formed (display). Formation process). Such a display may be in a form in which the mesh data 40 is locally removed or in a form in which the front surface or the back surface of the mesh data 40 is locally removed. The display to be formed is manually entered.

In step n-23, the mesh data 40 is output to a three-dimensional printer (not shown) in a stl format suitable for manufacturing a corrective helmet with a three-dimensional printer. Then, the required form of orthodontic helmet is manufactured by a three-dimensional printer.

2: Central processing device 4: Image display device 6: Scanning means P1: Serion P2: Tradion landmark P3: Tradion landmark PL0: Reference plane PL1 to PL9: Intermediate plane PL10: Apical plane CL: Center line IL1: Inclined Line IL2: Inclined line IS1: Ideal cranial shape HCL: Horizontal center line WL :: Width line IS2: Ideal cranial shape 3: Mesh data showing target correction cranial shape 5: Ear trace curve 7: Hollowed surface 8: Hollowed part 10: Compensation mesh part 12: Compensation mesh data 14: Offset mesh data 16: Front cut surface 18: Front cut mesh data 20: Horizontal plane passing through a predetermined collar height 22: Lower cut mesh data 24: Cut cylinder 26: Top surface hollow Opening 28: Top surface hollow mesh data 30: Kneading extension mesh data 32: Slit 34: Mesh data with thickness added and slits formed 36: Vent hole 38: Round bar 40: Mesh data for making a straightening helmet

Claims (29)

The scan data reading process that reads the three-dimensional scan data that shows the shape of the patient's skull,
Based on the three-dimensional scan data, an oblique head ideal correction data generation step of generating oblique head ideal correction data indicating a patient's oblique head ideal correction shape, and an oblique head ideal correction data generation step.
The process of specifying the plagiocephaly correction rate according to the degree of plagiocephaly, and the process of specifying the plagiocephaly correction rate.
A plagiocephaly correction target data generation process for generating plagiocephaly correction target data indicating a cranial shape based on the plagiocephaly ideal correction data and the plagiocephaly correction rate.
A method for obtaining a correction target skull shape, which comprises. The plagiocephaly ideal correction data generation step is
To set three reference points based on the three-dimensional scan data and set a reference plane including the three reference points.
To set a plurality of planes parallel to the reference plane and select one specific plane from the set plurality of planes.
Finding four intersections of two inclined lines and a skull shape that are inclined at predetermined angles in opposite directions to the center line extending in the anteroposterior direction in the specific plane.
The method for obtaining a correction target cranial shape according to claim 1, comprising the above. The method for obtaining the correction target cranial shape according to claim 2, wherein the three criteria are a selion and two tradion landmarks. Claim 2 or 3 includes the plurality of planes including an apex plane passing through the apex of the skull and parallel to the reference plane and an intermediate plane arranged at equal intervals between the reference plane and the apex plane. A method for obtaining the described correction target cranial shape. In order to assist the designation of the plagiocephaly correction rate, the skull shape corrected by the arbitrary plagiocephaly correction rate in the specific plane is displayed based on the plagiocephaly ideal correction data and an arbitrary plagiocephaly correction rate. The method for obtaining a correction target cranial shape according to any one of claims 2 to 4, which includes a display step to be performed. The scan data reading process that reads the three-dimensional scan data that shows the shape of the patient's skull,
Based on the three-dimensional scan data, a brachycephaly ideal correction data generation step of generating brachycephaly ideal correction data showing a patient's brachycephaly ideal correction shape, and a process of generating brachycephaly ideal correction data.
The process of specifying the brachycephaly correction rate according to the degree of brachycephaly and the process of specifying the brachycephaly correction rate,
Brachycephaly correction target data generation process for generating short head correction target data indicating the shape of the brachycephaly correction target based on the ideal correction data for the short head and the correction rate for the short head.
A method for obtaining a correction target skull shape, which comprises. The brachycephaly ideal correction data generation step is
Set a horizontal centerline that extends horizontally from the selion through the center of the skull and a width line that passes through both Tradion landmarks.
To set three reference points based on the three-dimensional scan data and set a reference plane including the three reference points.
To set a plurality of planes parallel to the reference plane and select one specific plane from the set plurality of planes.
The horizontal center line and a straight line in the width direction passing through both tradion landmarks are projected onto the specific plane, and two anteroposterior intersections of the horizontal center line and the cranial shape projected on the specific plane are obtained and projected. Finding the two widthwise intersections of the width line and the cranial shape,
Obtaining the length PLx between the two front-rear intersections and the length PLy between the two widthwise intersections, and calculating PLx / PLy.
6. The method for obtaining a correction target skull shape according to claim 6. The method for obtaining the correction target cranial shape according to claim 7, wherein the three reference points are a serion and two tradion landmarks. Claim 6 or 7 includes the plurality of planes including an apex plane passing through the apex of the skull and parallel to the reference plane and an intermediate plane arranged at equal intervals between the reference plane and the apex plane. How to determine the stated correction target skull. In order to assist in the designation of the brachycephaly correction rate, a display displaying the skull shape corrected by the arbitrary correction rate on the specific plane based on the ideal brachycephaly correction data and an arbitrary brachycephaly correction rate. The method for obtaining a correction target skull shape according to any one of claims 7 to 9, which includes a step. Find the length Lx from the selion to the intersection of the horizontal center line and the posterior surface of the skull and the length Ly of both tradion landmarks, and calculate Lx / Ly to see if brachycephaly correction is necessary. The method for obtaining a correction target skull shape according to any one of claims 6 to 10, which comprises determining whether or not. The scan data reading process that reads the three-dimensional scan data that shows the shape of the patient's skull,
Based on the three-dimensional scan data, an oblique head ideal correction data generation step of generating oblique head ideal correction data indicating a patient's oblique head ideal correction shape, and an oblique head ideal correction data generation step.
The process of specifying the plagiocephaly correction rate, which specifies the correction rate according to the degree of plagiocephaly,
A plagiocephaly correction target data generation step of generating a plagiocephaly correction target data indicating a cranial shape based on the plagiocephaly ideal correction data and the correction rate.
Based on the three-dimensional scan data, a brachycephaly ideal correction data generation step of generating brachycephaly ideal correction data showing a patient's brachycephaly ideal correction shape, and a process of generating brachycephaly ideal correction data.
The process of specifying the brachycephaly correction rate, which specifies the correction rate according to the degree of brachycephaly,
Brachycephaly correction target data generation process for generating short head correction target data indicating the shape of the short head correction target skull based on the ideal correction data for the short head and the correction rate, and a process for generating the target data for the short head correction.
A method for obtaining a correction target skull shape, which comprises. The plagiocephaly ideal correction data generation step is
To set three reference points based on the three-dimensional scan data and set a reference plane including the three reference points.
To set a plurality of planes parallel to the reference plane and select one specific plane from the set plurality of planes.
In the specific plane, a center line extending in the anteroposterior direction of the center of the skull and two inclined lines inclined at predetermined angles in opposite directions with respect to the center line are set.
Finding the four intersections of the two ramps and the skull shape,
12. The method for obtaining a correction target skull shape according to claim 12. In order to assist the designation of the plagiocephaly correction rate, a display step of displaying the skull shape corrected by the arbitrary correction rate on the specific plane based on the ideal correction rate of the plagiocephaly and an arbitrary correction rate is performed. The method for obtaining the correction target cranial shape according to claim 13, including the method. The brachycephaly ideal correction data generation step is
Set a horizontal centerline that extends horizontally to the center of the skull posteriorly from the selion and a width line that passes through both Tradion landmarks.
To set three reference points based on the three-dimensional scan data and set a reference plane including the three reference points.
To set a plurality of planes parallel to the reference plane and select one specific plane from the set plurality of planes.
The horizontal center line and the width line are projected onto the specific plane, the two anteroposterior intersections of the horizontal center line and the cranial shape projected on the specific plane are obtained, and the projected straight line in the width direction is obtained. Finding two horizontal intersections with the cranial shape,
Obtaining the length PLx between the two front-rear intersections and the length PLy between the two widthwise intersections, and calculating PLx / PLy.
The method for obtaining a correction target skull shape according to any one of claims 11 to 14, wherein the correction target skull shape is obtained. In order to assist in the designation of the brachycephaly correction rate, a display displaying the skull shape corrected by the arbitrary correction rate on the specific plane based on the ideal brachycephaly correction data and an arbitrary brachycephaly correction rate. The method for obtaining a correction target cranial shape according to claim 15, which includes a step. The method for obtaining the correction target cranial shape according to any one of claims 13 to 15, wherein the three reference points are a serion and two tradion landmarks. Claims 13 to 17 include the plurality of planes including an apex plane passing through the apex of the skull and parallel to the reference plane and an intermediate plane arranged at equal intervals between the reference plane and the apex plane. The method for obtaining the correction target cranial shape described in any of the above. Find the length Lx from the selion to the intersection of the horizontal center line and the posterior surface of the skull and the length Ly of both tradion landmarks, and calculate Lx / Ly to see if brachycephaly correction is necessary. The method for obtaining a correction target skull shape according to any one of claims 12 to 18, which comprises determining whether or not. Using a method to generate orthodontic helmet production data for producing an orthodontic helmet for correcting a deformed skull with a three-dimensional printer,
Correction target Cranial shape showing correction target Cranial shape data is imported into 3D CAD software, and a mesh data showing correction target skull surface shape is generated.
An offset step of offsetting the mesh data by a predetermined amount in the expansion direction,
A deletion process that deletes unnecessary parts from the mesh data,
A thickness imparting step of imparting a predetermined amount of thickness to the mesh data, and
An output process that outputs the mesh data that is offset in the expansion direction, has unnecessary parts removed, and is given a thickness.
A method characterized by including. The method according to claim 20, wherein the deletion step is performed after the offset step, and the thickness imparting step is performed after the deletion step. After the input step and before the offset step, a hollow curve is formed by hollowing out the left and right pinna based on the pinna trace curve that traces the left and right pinna, and the left and right hollow curves are connected to form a hollow surface. 20 or 21. The method of claim 20 or 21, comprising a pinna treatment step of forming, hollowing out the mesh data with the hollowed out surface, and further filling the cutout portion with a mesh defining a surface that is smoothly connected to the periphery. .. The removal step offsets the auricle trace curve by a predetermined amount in the enlargement direction, forms a front cut surface based on the offset auricle trace and serion, and cuts by the front cut surface, a predetermined collar height. By cutting down from the auricle, rounding the sharp part generated by the cut, and creating a cylinder centered on the center point of the auricle of the skull, which is inclined downward by a predetermined angle, The method according to any of claims 20 to 22, comprising cutting with a cut cylinder. The method according to any one of claims 20 to 23, which comprises a sideburn extension step of adding a sideburn extension mesh that extends a sideburns portion downward by a predetermined amount after the deletion step and before the output step. After the cutting step and before the output step, a slit extending continuously from the upper end edge to the lower end edge is formed adjacent to the sideburns portion, and the sharp portion generated by forming the slit is formed. The method according to any one of claims 20 to 24, comprising a step of forming a slit to be rolled. A ventilation hole forming step of forming a plurality of ventilation holes at intervals in a main region excluding an outer peripheral region having a predetermined width from the outer peripheral edge of the mesh data is included after the deletion step and before the output step. , The method according to any one of claims 20 to 25. After the slit forming step and before the output step, a solid round bar having a predetermined diameter extending continuously is formed along the outer peripheral edge of the mesh data except for the portion where the slit exists. 25. The method of claim 25, comprising a round bar joining step of joining the round bar to the mesh data and rounding the joint portion. The method according to any one of claims 20 to 27, comprising a display forming step of forming a display containing characters and / or symbols in a predetermined portion of the mesh data before the output step. The method according to any one of claims 20 to 28, wherein the mesh data is output in the stl format in the output step.

Images