Method for automatically generating a prosthesis from three-dimensional scan data, apparatus for automatically generating a prosthesis from three-dimensional scan data, and computer-readable recording medium having recorded thereon a program for causing a computer to execute the same

Abstract

To provide a method for automatically generating a prosthesis from a three-dimensional scan data by generating an intermediate surface of the prosthesis, generating an inner surface of the prosthesis, generating an outer surface of the prosthesis, and connecting the intermediate surface of the prosthesis and the outer surface of the prosthesis.SOLUTION: A method for automatically generating a prosthesis from a three-dimensional scan data includes: generating an intermediate surface of the prosthesis extending from a margin line of a prepared tooth in the three-dimensional scan data toward an outside of the tooth; generating an inner surface of the prosthesis by setting a gap from a surface of the prepared tooth; generating an outer surface of the prosthesis; and connecting the outer surface of the prosthesis and the intermediate surface of the prosthesis.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for automatically generating a prosthesis from three-dimensional scan data, an apparatus for automatically generating a prosthesis from three-dimensional scan data, and a computer-readable recording medium having a program recorded thereon for causing a computer to execute the same. More specifically, the present invention relates to a method for automatically generating a prosthesis from three-dimensional scan data, an apparatus for automatically generating a prosthesis from three-dimensional scan data, and a computer-readable recording medium having a program recorded thereon for causing a computer to execute the same, by generating an intermediate surface of the prosthesis, generating an inner surface of the prosthesis, generating an outer surface of the prosthesis, and connecting the intermediate surface of the prosthesis and the outer surface of the prosthesis.

Background Art

[0002] Three-dimensional oral scan data refers to data obtained by scanning teeth, the oral cavity, or an object imitating or reconstructing the same with a three-dimensional scanner. Dental treatments such as inlay, onlay, crown, implant, and orthodontics acquire a patient's oral data and are used for prosthesis or implant design, orthodontic appliance production, etc.

[0003] Conventionally, a method of directly imitating the oral cavity using alginate or the like and then manually producing a prosthesis has been mainly used. In order to make an anatomically correct prosthesis, a dentist or dental technician grasps the degree of wear of the surrounding teeth, comprehensively understands the tooth numbers of the teeth and the meshing information of the opposing teeth, and then generates a result. The conventional prosthesis generation method can be manually modified according to the oral condition of each patient based on a general tooth shape in consideration of such information.

[0004] In addition, conventionally, since the process of generating a prosthesis is performed manually, there are problems such as an increase in the work fatigue of dentists or dental technicians, a decrease in the accuracy and productivity of the result, and a large deviation in the quality and required time of the prosthesis depending on the skill level of the operator.

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a method for automatically generating a prosthesis from three-dimensional scan data by steps of generating an intermediate surface of the prosthesis, generating an inner surface of the prosthesis, generating an outer surface of the prosthesis, and connecting the intermediate surface of the prosthesis and the outer surface of the prosthesis.

[0006] Another object of the present invention is to provide an apparatus for automatically generating a prosthesis from three-dimensional scan data.

[0007] Still another object of the present invention is to provide a computer-readable recording medium having recorded thereon a program for causing a computer to execute a method for automatically generating a prosthesis from the three-dimensional scan data.

Means for Solving the Problems

[0008] A method for automatically generating a prosthesis from three-dimensional scan data according to an embodiment for realizing the object of the present invention described above includes generating an intermediate surface of the prosthesis extending from a margin line of a prepared (PREP) tooth in the three-dimensional scan data toward the outside of the tooth, setting a distance from the surface of the prepared tooth to generate an inner surface of the prosthesis, generating an outer surface of the prosthesis, and connecting the outer surface of the prosthesis and the intermediate surface of the prosthesis.

[0009] The intermediate surface is determined by a width of the predetermined intermediate surface and an intermediate surface direction vector extending from the margin line.

[0010] The intermediate surface is determined based on the margin line, an insertion direction of the prosthesis, a width of the intermediate surface, and an angle condition.

[0011] The intermediate surface direction vector is determined by rotating the first direction vector around the second direction vector according to the angle condition. The second direction vector is the cross product of the insertion direction vector representing the insertion direction and the first direction vector.

[0012] The first direction vector of the margin line point within the margin line is the normal vector of the mesh of the three-dimensional scan data including the margin line point.

[0013] The margin line includes k-1 margin line points, k margin line points, and k+1 margin line points adjacent to each other. When the k-1 margin line point is P k-1 and the k+1 margin line point is P k+1 and the first direction vector of the k margin line point is V1 and the insertion direction vector is I, then V = P k+1 - P k-1 and V1 = I × V are satisfied.

[0014] The step of generating the intermediate surface of the patch further includes the step of obtaining a slave vector, a tangent vector, and a reference vector by the rotation minimizing frames method at the margin line points within the margin line. The first direction vector of the margin line point is determined by the reference vector of the margin line point.

[0015] When the insertion direction is I, the number of faces of the prepared mesh data of the prepared tooth is N, and the normal vectors of the faces of the prepared mesh data are JPEG0007699848000001.jpg6170 and xopt is the direction in which the normal vector of the point of the prepared mesh data is not hidden, and T is the swapping function that exchanges the rows and columns of the matrix, JPEG0007699848000002.jpg8170 satisfies

[0016] The step of generating the inner surface of the prosthesis includes determining a no cement gap that does not set a distance from the surface of the prepared tooth, determining a cement gap that sets a first distance from the surface of the prepared tooth, and determining an additional cement gap that sets a further distance from the cement gap.

[0017] The no cement gap and the cement gap are determined based on the geodesic distance from the plane formed by the margin line.

[0018] The additional cement gap is determined based on the geodesic distance from the plane formed by the margin line and the curvature value of the prepared tooth.

[0019] The greater the curvature value, the greater the additional cement gap is determined.

[0020] The step of generating the inner surface of the prosthesis further includes removing a portion where the distance from the plane formed by the margin line is negative from the prepared mesh data corresponding to the prepared tooth.

[0021] The step of generating the inner surface of the prosthesis further includes, when drawing a straight line parallel to the insertion direction of the prosthesis to meet the prepared tooth, converting a portion where the prepared tooth does not exist among the regions inside the two outermost straight lines into a portion where the prepared tooth exists.

[0022] The step of generating the outer surface of the prosthesis includes the step of placing a dental library model corresponding to the prepared tooth at the position of the prepared tooth, and the step of deforming the dental library model into pre-op data representing the state of the prepared tooth before preparation.

[0023] The step of generating the outer surface of the prosthesis includes the step of placing a dental library model corresponding to the prepared tooth at the position of the prepared tooth, and the step of deforming the dental library model into prosthesis outer surface data obtained by an artificial intelligence neural network.

[0024] Furthermore, when the distance from the inner surface to the outer surface is smaller than the minimum thickness value from the inner surface, the step of modifying the outer surface is included so that the distance from the inner surface to the outer surface has the minimum thickness value from the inner surface.

[0025] Furthermore, the step of modifying the outer surface is included by using a first distance between the prepared tooth and an adjacent tooth and a second distance between the prepared tooth and an opposing tooth.

[0026] The step of connecting the outer surface of the prosthesis and the intermediate surface of the prosthesis moves the coordinates of the lower part of the outer surface that do not coincide with the intermediate surface to the coordinates of the intermediate surface.

[0027] A method for automatically generating a prosthesis from three-dimensional scan data according to an embodiment for realizing the object of the present invention described above includes the step of determining the dental formula of a prepared tooth from three-dimensional scan data using a first artificial intelligence neural network, the step of determining the margin line of the prepared tooth using a second artificial intelligence neural network, the step of generating an intermediate surface of the prosthesis extending from the margin line of the prepared tooth toward the outside of the tooth, the step of generating an inner surface of the prosthesis by setting a distance from the surface of the prepared tooth, the step of generating an outer surface of the prosthesis using a third artificial intelligence neural network, and the step of connecting the outer surface of the prosthesis and the intermediate surface of the prosthesis.

[0028] An apparatus for automatically generating a prosthesis from three-dimensional scan data according to an embodiment for realizing the above-described object of the present invention generates an intermediate surface of the prosthesis extending from the margin line of the prepared tooth in the three-dimensional scan data toward the outside of the tooth, sets a distance from the surface of the prepared tooth, generates an inner surface of the prosthesis, generates an outer surface of the prosthesis, and is characterized by connecting the outer surface of the prosthesis and the intermediate surface of the prosthesis.

[0029] In one embodiment of the present invention, a program for causing a computer to execute a method for automatically generating a prosthesis from the three-dimensional scan data is recorded on a computer-readable recording medium. [Effect of the Invention]

[0030] According to the method and apparatus for automatically generating a prosthesis from three-dimensional scan data according to the present invention, a prosthesis can be automatically generated by steps of generating an intermediate surface of the prosthesis, generating an inner surface of the prosthesis, generating an outer surface of the prosthesis, and connecting the intermediate surface of the prosthesis and the outer surface of the prosthesis.

[0031] In conventional dental CAD software, depending on the skill level of the user, there are significant differences in the time required to generate the prosthesis and the quality of the prosthesis. In the method of manually generating a prosthesis considering opposing teeth, adjacent teeth, etc., significant differences in the resulting products occur depending on the skill level of the user. In the present invention, when the three-dimensional scan data and user parameters are input, a prosthesis is automatically generated from the three-dimensional scan data, and even a user who is not good at generating a prosthesis can generate a high-quality prosthesis within a short time. [Brief Description of the Drawings]

[0032]

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DETAILED DESCRIPTION OF THE INVENTION

[0033] Regarding the embodiments of the present invention shown in the text, the specific structural or functional explanations are merely exemplified for the purpose of explaining the embodiments of the present invention. The embodiments of the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described in the text.

[0034] The present invention can be subjected to various modifications and can have various forms. Specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, and it should be understood that all modifications, equivalents, and alternatives included within the spirit and technical scope of the present invention are included.

[0035] Terms such as first, second, etc. are used to describe various components, but the components should not be limited by the terms. The terms are used for the purpose of distinguishing one component from another. For example, without departing from the scope of the rights of the present invention, the first component can be referred to as the second component, and similarly, the second component can also be referred to as the first component.

[0036] When a certain component is said to be “connected to” or “connected with” another component, it should be understood that it can be directly connected or connected to the other component, but other components can also exist in the middle. On the other hand, when a certain component is said to be “directly connected to” or “directly connected with” another component, it should be understood that no other component exists in the middle. Other expressions for explaining the relationship between components, that is, “between ~” and “immediately between ~”, or “adjacent to ~” and “directly adjacent to ~” should be analyzed in the same way.

[0037] The terms used in this application are merely used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "including" or "having" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and it should be understood that the presence or addition possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof is not precluded in advance.

[0038] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or overly formal sense unless clearly defined in this application.

[0039] On the other hand, when a certain embodiment can be implemented differently, the functions or operations specified within a specific block can occur differently from the procedures specified in the flowchart. For example, two consecutive blocks can actually be performed substantially simultaneously, and depending on the related functions or operations, the blocks can also be performed in reverse.

[0040] Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in more detail. The same reference numerals are assigned to the same components in the drawings, and duplicate descriptions of the same components are omitted.

[0041] FIG. 1 is a flowchart showing a method for automatically generating a prosthesis from three-dimensional scan data according to an embodiment of the present invention.

[0042] As shown in FIG. 1, a method for automatically generating a prosthesis from three-dimensional scan data according to an embodiment of the present invention includes a step (S200) of generating an intermediate surface of the prosthesis extending outward from the margin line of the prepared tooth in the three-dimensional scan data, a step (S300) of setting a distance from the surface of the prepared tooth to generate an inner surface of the prosthesis, a step (S400) of generating an outer surface of the prosthesis, and a step (S500) of connecting the outer surface and the intermediate surface of the prosthesis.

[0043] An apparatus for automatically generating a prosthesis from three-dimensional scan data according to an embodiment of the present invention generates an intermediate surface of the prosthesis extending outward from the margin line of the prepared tooth in the three-dimensional scan data, sets a distance from the surface of the prepared tooth to generate an inner surface of the prosthesis, generates an outer surface of the prosthesis, and connects the outer surface and the intermediate surface of the prosthesis.

[0044] The method for automatically generating a prosthesis from the three-dimensional scan data further includes a step (step S100) of inputting the three-dimensional scan data and user parameters.

[0045] The method for automatically generating a prosthesis from the three-dimensional scan data further includes a step (step S600) of correcting the outer surface such that when the distance from the inner surface to the outer surface is smaller than the minimum thickness value from the inner surface, the distance from the inner surface to the outer surface has the minimum thickness value from the inner surface.

[0046] The method for automatically generating a prosthesis from the three-dimensional scan data further includes a step (step S600) of correcting the outer surface using a first distance to an adjacent tooth of the prepared tooth and a second distance to an opposing tooth of the prepared tooth.

[0047] Here, the three-dimensional scan data refers to data obtained by scanning teeth, the oral cavity, or an object imitating or reconstructed therefrom using a three-dimensional scanner. For example, the three-dimensional scan data is mesh data including three-dimensional points (vertices) and triangular faces (Triangles) or rectangular faces (Rectangles) generated by connecting the points. There is no restriction on the file extension of the three-dimensional scan data, and for example, it can be any one of ply, obj, and stl.

[0048] Here, the prepared tooth means a tooth prepared for a crown, and the prepared tooth means a tooth from which a part of the tooth has been cut. Specifically, in order to generate a single crown, it is necessary to cut out the entire natural tooth so that it is easy to cover with a prosthesis, and the natural tooth that has gone through this process is referred to as the prepared tooth. Also, the margin line means the edge of the prepared tooth. The margin line indicates the boundary between the prepared tooth and the tooth root.

[0049] In the case of the three-dimensional scan data, preprocessing is required. For example, the upper jaw scan data and the lower jaw scan data are aligned. Also, the upper jaw scan data, the lower jaw scan data, and the bite scan data are aligned.

[0050] For example, if there is pre-op scan data including the state of the prepared tooth before preparation, the pre-op scan data is also aligned with the scan data in which the prepared tooth exists.

[0051] In order to automatically generate a prosthesis from the three-dimensional scan data, a plurality of basic data is required. The basic data includes the tooth formula of the target tooth, the margin line of the target tooth, the insertion direction of the prosthesis, the adjacent tooth information of the target tooth, the occlusal surface information, the opposing tooth information, and the like. The basic data is automatically determined from the three-dimensional scan data by artificial intelligence. Different from this, the basic data can be determined within the program. The basic data determined within the artificial intelligence or the program can be modified by the user.

[0052] The insertion direction of the prosthesis, which is the direction in which the prosthesis model is inserted into the prepared tooth, is determined using the normal vector of the surface of the prepared mesh data of the prepared tooth.

[0053] For example, when the insertion direction is I, the number of surfaces of the prepared mesh data is N, and the normal vector is JPEG0007699848000003.jpg6170 and x opt is the direction in which the normal vector of the point of the prepared mesh data is not hidden, and T is the swapping function that exchanges the rows and columns of the matrix, then JPEG0007699848000004.jpg8170 is satisfied.

[0054] In the direction x, expressing the fact that the normal vector n is not hidden by an equation, x T n > 0, which means that the angle between x and n is an acute angle. When the angle between x and n is an acute angle, x T n > 0, and when the angle between x and n is a right angle, x T n = 0, and when the angle between x and n is an obtuse angle, x T n < 0. Therefore, xopt is the direction in which the average value of the angles with the normal vectors on the surfaces of each prepared mesh data is the lowest.

[0055] A method for automatically generating a prosthesis from three-dimensional scan data according to an embodiment of the present invention includes: determining a tooth form of a prepared tooth from the three-dimensional scan data using a first artificial intelligence neural network; determining a margin line of the prepared tooth using a second artificial intelligence neural network; generating an intermediate surface of the prosthesis extending from the margin line of the prepared tooth toward the outside of the tooth; generating an inner surface of the prosthesis by setting a distance from the surface of the prepared tooth; generating an outer surface of the prosthesis using a third artificial intelligence neural network; and connecting the outer surface and the intermediate surface of the prosthesis. In this embodiment, the tooth form of the prepared tooth is automatically determined using the first artificial intelligence neural network, the margin line of the prepared tooth is automatically determined using the second artificial intelligence neural network, and the outer surface of the prosthesis is automatically generated using the third artificial intelligence neural network.

[0056] The method for automatically generating a prosthesis from three-dimensional scan data of the present invention is performed by a computing device.

[0057] FIG. 2 is a diagram showing the outer surface and the intermediate surface of the prosthesis. FIG. 3 is a diagram showing a prepared tooth and the intermediate surface of the prosthesis corresponding to the prepared tooth.

[0058] Referring to FIGS. 1 to 3, the intermediate surface means a portion extending from the margin line of the prepared tooth in the three-dimensional scan data toward the outside of the tooth. The intermediate surface means a surface connecting the outer surface and the inner surface, and is the portion of the prosthesis closest to the patient's gum.

[0059] For example, the intermediate surface is determined by a width of the predetermined intermediate surface and an intermediate surface direction vector extending from the margin line. The intermediate surface is determined based on the margin line, the insertion direction of the prosthesis, the width of the intermediate surface, and angle conditions.

[0060] Here, the width of the intermediate surface is a user parameter that can be appropriately adjusted by the user. Also, the angle condition is the user parameter. In contrast, the width of the intermediate surface and the angle condition are predetermined values.

[0061] For example, the angle condition represents the angle at which the intermediate surface of the prosthesis extends so that the intermediate surface of the prosthesis does not protrude into the patient's gums.

[0062] FIG. 4 is a diagram showing the intermediate surface direction vector used in the intermediate surface generation step of FIG. 1.

[0063] Referring to FIGS. 1 to 4, the intermediate surface direction vector is determined by rotating the first direction vector (V1) around the second direction vector (V2) according to the angle condition (Bottom angle in FIG. 4).

[0064] The second direction vector (V2) is the cross product of the insertion direction vector (I) representing the insertion direction and the first direction vector (V1). JPEG0007699848000005.jpg5170 Here, the first direction vector (V1) means a vector substantially parallel to the plane formed by the margin line and can be obtained by various methods.

[0065] FIG. 5 is a diagram showing an example of generating the first direction vector used in the intermediate surface generation step of FIG. 1.

[0066] Referring to FIGS. 1 to 5, the first direction vector of the margin line points within the margin line is the normal vector of the mesh (Prep mesh) of the three-dimensional scan data including the margin line points.

[0067] FIG. 6 is a diagram showing an example of generating the first direction vector used in the intermediate surface generation step of FIG. 1.

[0068] Referring to FIGS. 1 to 4 and FIG. 6, the margin line has k - 1 margin line points (P k-1 ) adjacent to each other, a k margin line point (P k ), and a k + 1 margin line point (P k+1 ). The k - 1 margin line point is P k-1 , the k + 1 margin line point is P k+1 , and when the first direction vector of the k margin line point (P k ) is V1 and the insertion direction vector is 1, V = P k+1 - P k-1 , and V1 = I × V is satisfied.

[0069] FIG. 7 is a diagram showing an example of generating a first direction vector used in the intermediate surface generation step of FIG. 1.

[0070] Referring to FIGS. 1 to 4 and FIG. 7, the step (S200) of generating the intermediate surface of the patch further includes the step of obtaining slave vector(s), tangent vector(t), and reference vector(r) by the rotation minimizing frames method at the margin line points within the margin line. The first direction vector of the margin line point is determined by the reference vector of the margin line point.

[0071] The margin line has k - 1 margin line points (P k-1 ) adjacent to each other, a k margin line point (P k ), and a k + 1 margin line point (P k+1 ). The first direction vector of the k - 1 margin line point (P k-1 ) is r k-1 in FIG. 7. The first direction vector of the k margin line point (P k ) is r k in FIG. 7. The first direction vector of the k + 1 margin line point (P k+1) The first direction vector of is r in FIG. 7 k+1 is as follows.

[0072] FIG. 8 is a flowchart showing the inner surface generation step of FIG. 1. FIG. 9 is a diagram showing the undercut region removal step of FIG. 8. FIG. 10 is a diagram showing the geodesic distance used in the step of generating a no cement gap, a cement gap, and an additional cement gap in FIG. 8. FIG. 11 is a diagram showing the no cement gap, the cement gap, and the additional cement gap in FIG. 8.

[0073] Referring to FIGS. 1 to 11, the step of generating the inner surface of the prosthesis includes a step (S310) of generating a prepared region based on the margin line, a step (S320) of removing an undercut region, a step (S330) of determining a no cement gap, a cement gap, and an additional cement gap, and a step (S340) of applying the no cement gap, the cement gap, and the additional cement gap to the surface of the prepared region to generate the inner surface of the prosthesis.

[0074] For example, in the step (S310) of generating the prepared region based on the margin line, a portion where the distance from the plane formed by the margin line is negative can be removed from the prepared mesh data corresponding to the prepared tooth.

[0075] For example, in the step (S320) of removing the undercut region, when a straight line parallel to the insertion direction of the prosthesis is drawn to meet the prepared tooth, a portion of the region that exists inside the two outermost straight lines and where the prepared tooth does not exist can be converted into a portion where the prepared tooth exists.

[0076] In the upper diagram of FIG. 9, the portion indicated as the undercut region is a portion where the prepared teeth do not exist among the regions that exist inside the two outermost straight lines among the parallel straight lines, and this portion can be converted into a portion where the prepared teeth exist as shown in the lower diagram of FIG. 9. The non-cement gap means a region having no interval from the surface of the prepared tooth. As shown in FIG. 11, the region corresponding to the non-cement gap height has a non-cement gap on the inner surface. Due to the non-cement gap, the adhesive filled in the cement gap and the additional cement gap does not flow out.

[0077] The cement gap means a region having a first interval from the surface of the prepared tooth. The cement gap is filled with an adhesive, and the prepared tooth and the prosthesis are adhered.

[0078] The non-cement gap and the cement gap are determined based on the geodesic distance from the plane formed by the margin line. The geodesic distance from the plane formed by the margin line is shown in FIG. 10.

[0079] For example, among the prepared regions, the region where the geodesic distance is smaller than the threshold distance is determined as the non-cement gap. Among the prepared regions, the region where the geodesic distance is greater than or equal to the threshold distance is determined as the cement gap.

[0080] The additional cement gap means a region having a further interval from the cement gap. The additional cement gap is filled with an adhesive, and the prepared tooth and the prosthesis are adhered. The additional cement gap is set in a portion where it is determined that the prepared tooth and the prosthesis cannot be sufficiently adhered only by the cement gap.

[0081] For example, the additional cement gap is determined based on the geodesic distance from the plane formed by the margin line and the curvature value of the prepared tooth.

[0082] The larger the curvature value, the larger the additional cement gap is determined. The location with a large curvature value is a region where the adhesive is relatively likely to flow down. Therefore, by further setting the additional cement gap, the adhesiveness between the prepared tooth and the prosthesis can be enhanced.

[0083] For example, in the prepared region, the region where the geodesic distance is greater than or equal to the threshold distance and the curvature value of the prepared tooth is greater than or equal to the threshold curvature value is determined as the additional cement gap.

[0084] The bottom in FIG. 11 means the width of the intermediate surface, and the bottom angle means the intermediate surface direction vector determined by the angle condition.

[0085] FIG. 12 is a flowchart showing the outer surface generation step in FIG. 1.

[0086] Referring to FIGS. 1 to 12, for example, the step of generating the outer surface of the prosthesis includes arranging a dental library model corresponding to the prepared tooth at the position of the prepared tooth (step S410), and deforming the dental library model into pre-op data representing the state of the prepared tooth before preparation (step S420).

[0087] Alternatively, the step of generating the outer surface of the prosthesis may include arranging a dental library model corresponding to the prepared tooth at the position of the prepared tooth (step S410), and deforming the dental library model into prosthesis outer surface data obtained by an artificial intelligence neural network (step S420).

[0088] The tooth library model is a kind of sample tooth (standard tooth) used for manufacturing dentures, implants, orthodontic appliances, etc., and has a typical tooth shape. The tooth library model has one sample tooth (standard tooth) for each tooth number. The three-dimensional oral scan data is taken by a scanner, and the mesh completion degree is somewhat low. When the mesh completion degree is low, it is not suitable for manufacturing dentures, implants, orthodontic appliances, etc. by 3D printing. On the contrary, the three-dimensional tooth library model is a tooth model with a high mesh completion degree. Therefore, when deforming the three-dimensional tooth library model to manufacture dentures, implants, orthodontic appliances, etc., it is very suitable to use the 3D printing method. Therefore, when aligning the three-dimensional tooth library model with the oral scan data of the patient, it can be an appropriate intermediate model for manufacturing dentures, implants, orthodontic appliances, etc. in a digital manner.

[0089] In the step of arranging the tooth library model at the position of the prepared tooth, landmarks can be used. Extract the landmarks of the three-dimensional scan data and the landmarks of the tooth library model, and arrange the tooth library model on the three-dimensional scan data so that the landmarks of the three-dimensional scan data and the landmarks of the tooth library model match.

[0090] FIG. 13 is a diagram showing the intermediate surface and outer surface connection step of FIG. 1.

[0091] Referring to FIGS. 1 to 13, in the step of connecting the outer surface and the intermediate surface of the prosthesis, the coordinates of the lower part of the outer surface that do not match the intermediate surface are moved to the coordinates of the intermediate surface.

[0092] For example, find the pair of the outer surface model (deformed library model) of the prosthesis generated at the target tooth position and the outermost contour line of the intermediate surface, and deform the outer surface model so that the outer surface model fits the outermost contour line of the intermediate surface.

[0093] FIG. 14 is a diagram showing the minimum thickness used in the minimum thickness adjustment step of FIG. 1. FIG. 15 is a diagram showing the minimum thickness adjustment step of FIG. 1. FIG. 16 is a diagram showing the minimum thickness adjustment step of FIG. 1.

[0094] Referring to FIGS. 1 to 16, the method for automatically generating a prosthesis from 3D scan data further includes the step of modifying the outer surface such that the distance from the inner surface to the outer surface has the minimum thickness value from the inner surface when the distance from the inner surface to the outer surface is smaller than the minimum thickness value from the inner surface (step S600).

[0095] As shown in the left diagram of FIG. 14, the minimum thickness value is defined from the inner surface of the prosthesis. The minimum thickness value means the thickness value required for stably generating the prosthesis by 3D printing or milling or the like.

[0096] The right diagram of FIG. 14 shows a minimum thickness model generated by expanding by the minimum thickness from the inner surface of the prosthesis.

[0097] The outer surface of the prosthesis can be deformed such that the outer surface of the prosthesis is located outside the outer surface of the minimum thickness model.

[0098] As shown in FIG. 15, since the outer surface of the prosthesis is located outside the outer surface of the minimum thickness model as a whole, it is not necessary to deform the outer surface of the prosthesis.

[0099] On the contrary, as shown in FIG. 16, since a part of the outer surface of the prosthesis is located inside the outer surface of the minimum thickness model, the outer surface of the prosthesis located inside the outer surface of the minimum thickness model can be deformed to coincide with the minimum thickness model.

[0100] FIG. 17 is a diagram showing the contact area correction step of FIG. 1.

[0101] Referring to FIGS. 1 to 17, the method for automatically generating a prosthesis from three-dimensional scan data further includes a step of correcting the outer surface using a first distance between the prepared tooth and an adjacent tooth and a second distance between the prepared tooth and an opposing tooth (step S600).

[0102] Here, the first distance from the adjacent tooth and the second distance from the opposing tooth are user parameters input by the user.

[0103] According to the present embodiment, a prosthesis can be automatically generated by generating a middle surface of the prosthesis, generating an inner surface of the prosthesis, generating an outer surface of the prosthesis, and connecting the middle surface of the prosthesis and the outer surface of the prosthesis.

[0104] In conventional dental CAD software, depending on the proficiency of the user, there are significant differences in the time required to generate the prosthesis and the quality of the prosthesis. In the method of manually generating a prosthesis by considering the opposing teeth, adjacent teeth, etc., depending on the proficiency of the user, significant differences in the resulting products occur. In the present invention, when the three-dimensional scan data and user parameters are input, a prosthesis is automatically generated from the three-dimensional scan data, and even a user who is not good at generating a prosthesis can generate a high-quality prosthesis within a short time.

[0105] According to an embodiment of the present invention, there is provided a computer-readable recording medium having recorded thereon a program for causing a computer to execute a method for automatically generating a prosthesis from three-dimensional scan data according to the embodiment. The method can be created by a program executed by a computer and can be implemented on a general-purpose digital computer that operates the program using a computer-readable medium. Also, the data structure used in the method is recorded on the computer-readable medium by a plurality of means. The computer-readable medium can include program instructions, data files, data structures, etc., alone or in combination. The program instructions recorded on the medium are those specially designed and configured for the present invention and those known and usable by ordinary technicians in the field of computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical recording media such as CD-ROMs and DVDs, magneto-optical media such as optical disks, and hardware devices specially configured to store and execute program instructions such as ROMs, RAMs, and flash memories. The program instructions include not only machine language codes created by compilers but also high-level language codes executed by a computer using an interpreter or the like. The above-described hardware device is configured to operate as one or more software modules for performing the operations of the present invention.

[0106] Also, the method for automatically generating a prosthesis from the three-dimensional scan data described above can also be implemented in the form of a computer program executed by a computer stored on a recording medium or an application. [Industrial Applicability]

[0107] The present invention relates to a method for automatically generating a prosthesis from three-dimensional scan data, an apparatus for automatically generating a prosthesis from three-dimensional scan data, and a computer-readable recording medium on which a program for causing a computer to execute the same is recorded, which can reduce the effort and time for manufacturing the prosthesis and improve the accuracy and productivity of the prosthesis.

[0108] In the above, the preferred embodiments of the present invention have been described with reference to the drawings. However, those skilled in the art in the relevant technical field will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the present invention described in the following claims.

Claims

1. Generating an intermediate surface of a prosthesis extending from a prepared tooth margin line in the three-dimensional scan data towards the outside of the tooth; Setting a distance from the surface of the prepared tooth to generate an inner surface of the prosthesis; Generating an outer surface of the prosthesis; Connecting the outer surface and the intermediate surface of the prosthesis; comprising: The prepared tooth is a tooth obtained by cutting a part of a natural tooth; The step of generating the inner surface of the prosthesis includes: Generating an adjusted region based on the margin line; Removing an undercut region; Determining a cementless gap that does not set a distance from the surface of the prepared tooth; Determining a cement gap that sets a first distance from the surface of the prepared tooth; Determining an additional cement gap that sets a further distance from the cement gap, and including: In the step of generating the adjusted region based on the margin line, a portion where the distance from the plane formed by the margin line is negative is removed from the prepared mesh data corresponding to the prepared tooth; In the step of removing the undercut region, when a straight line parallel to the insertion direction of the prosthesis is drawn to meet the prepared tooth, among the parallel straight lines, a portion where the prepared tooth does not exist in the region inside the two outermost straight lines is converted into a portion where the prepared tooth exists; The cementless gap and the cement gap are based on the geodesic distance from the plane formed by the margin line. Among the adjusted regions, a region where the geodesic distance is smaller than a threshold distance is determined as the cementless gap, and a region where the geodesic distance is greater than or equal to the threshold distance in the adjusted region is determined as the cement gap; The additional cement gap is based on the geodesic distance from the plane formed by the margin line and the curvature value of the prepared tooth. Among the adjusted regions, a region where the geodesic distance is greater than or equal to the threshold distance and the curvature value of the prepared tooth is greater than or equal to a threshold curvature value is determined as the additional cement gap, and the additional cement gap is determined to be larger as the curvature value is larger. A method for automatically generating prosthesis data from three-dimensional scan data.

2. The method for automatically generating patch data from three-dimensional scan data according to claim 1, wherein the intermediate surface is determined by a width of the predetermined intermediate surface and an intermediate surface direction vector extending from the margin line.

3. The intermediate surface is determined based on the margin line, the insertion direction of the patch, the width of the intermediate surface, and an angle condition. The method for automatically generating patch data from three-dimensional scan data according to claim 2.

4. The intermediate surface direction vector is determined by rotating a first direction vector around a second direction vector according to the angle condition. The second direction vector is an outer product of an insertion direction vector representing the insertion direction and the first direction vector. The method for automatically generating patch data from three-dimensional scan data according to claim 3.

5. The first direction vector of a margin line point within the margin line is a normal vector of a mesh of the three-dimensional scan data including the margin line point. The method for automatically generating patch data from three-dimensional scan data according to claim 4.

6. The margin line includes k-1 margin line points, k margin line points, and k+1 margin line points adjacent to each other. The k - 1 margin line point is P k-1 and the k + 1 margin line point is P k+1 and when the first direction vector of the k margin line point is V1 and the insertion direction vector is I, V = P k+1 - P k-1 satisfies V1 = I × V, characterized by The method for automatically generating patch data from three-dimensional scan data according to claim 4.

7. The step of generating the intermediate surface of the patch further includes obtaining a slave vector, a tangent vector, and a reference vector by a rotation minimizing frames method at a margin line point within the margin line. The first direction vector of the margin line point is determined by the reference vector of the margin line point. The method for automatically generating patch data from three-dimensional scan data according to claim 4.

8. The insertion direction is I, the number of faces of the prepared mesh data of the prepared tooth is N, and the normal vector of the face of the prepared mesh data is where xopt is a direction in which the normal vector of the point of the prepared mesh data is not hidden, and T is a swapping function that exchanges rows and columns of a matrix. It is characterized by satisfying A method for automatically generating prosthesis data from the three-dimensional scan data according to claim 3.

9. The step of generating the outer surface of the prosthesis comprises: placing a dental library model corresponding to the prepared tooth at the position of the prepared tooth; deforming the dental library model into pre-op data representing the state of the prepared tooth before preparation, and is characterized by including: A method for automatically generating prosthesis data from the three-dimensional scan data according to claim 1.

10. The step of generating the outer surface of the prosthesis comprises: placing a dental library model corresponding to the prepared tooth at the position of the prepared tooth; deforming the dental library model into prosthesis outer surface data obtained by an artificial intelligence neural network, and is characterized by including: A method for automatically generating prosthesis data from the three-dimensional scan data according to claim 1.

11. Furthermore, when the distance from the inner surface to the outer surface is smaller than the minimum thickness value from the inner surface, the method includes the step of modifying the outer surface so that the distance from the inner surface to the outer surface has the minimum thickness value from the inner surface, and is characterized by including: A method for automatically generating prosthesis data from the three-dimensional scan data according to claim 1.

12. Furthermore, the method includes the step of modifying the outer surface by using a first distance between the prepared tooth and an adjacent tooth and a second distance between the prepared tooth and an opposing tooth, and is characterized by including: A method for automatically generating prosthesis data from the three-dimensional scan data according to claim 1.

13. The step of connecting the outer surface of the prosthesis and the intermediate surface of the prosthesis comprises: moving the coordinates of the lower part of the outer surface that do not coincide with the intermediate surface to the coordinates of the intermediate surface, and is characterized by: A method for automatically generating prosthesis data from the three-dimensional scan data according to claim 1.

14. generating an intermediate surface of a prosthesis extending from a margin line of a prepared tooth in the three-dimensional scan data toward the outside of the tooth; generating an inner surface of the prosthesis by setting a distance from the surface of the prepared tooth; generating an outer surface of the prosthesis; connecting the outer surface of the prosthesis and the intermediate surface of the prosthesis; the prepared tooth is a tooth obtained by shaving a part of a natural tooth; generating the inner surface of the prosthesis comprises: generating an adjusted area based on the margin line; removing an undercut area; Determining a cementless gap that does not set a distance from the surface of the prepared tooth, Determining a cement gap that sets a first distance from the surface of the prepared tooth, Determining an additional cement gap that sets a further distance from the cement gap, and including: In generating the adjusted region based on the margin line, from the prepared mesh data corresponding to the prepared tooth, a portion where the distance from the plane formed by the margin line is negative is removed, In removing the undercut region, when a straight line parallel to the insertion direction of the prosthesis is drawn to meet the prepared tooth, among the parallel straight lines, a portion of the region that exists inside the two outermost straight lines and where the prepared tooth does not exist is converted into a portion where the prepared tooth exists, The cementless gap and the cement gap are determined based on the geodesic distance from the plane formed by the margin line. Among the adjusted regions, a region where the geodesic distance is smaller than the threshold distance is determined as the cementless gap, and a region where the geodesic distance is greater than or equal to the threshold distance among the adjusted regions is determined as the cement gap, The additional cement gap is determined based on the geodesic distance from the plane formed by the margin line and the curvature value of the prepared tooth. Among the adjusted regions, a region where the geodesic distance is greater than or equal to the threshold distance and the curvature value of the prepared tooth is greater than or equal to the threshold curvature value is determined as the additional cement gap, and the additional cement gap is determined to be larger as the curvature value is larger, An apparatus for automatically generating prosthesis data from three-dimensional scan data.

15. A computer-readable recording medium on which a program for causing a computer to execute the method according to any one of Claims 1 to 13 is recorded.

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