CN116012529B - Virtual root generating method, device, computer equipment and storage medium - Google Patents
Virtual root generating method, device, computer equipment and storage medium Download PDFInfo
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- CN116012529B CN116012529B CN202211660062.6A CN202211660062A CN116012529B CN 116012529 B CN116012529 B CN 116012529B CN 202211660062 A CN202211660062 A CN 202211660062A CN 116012529 B CN116012529 B CN 116012529B
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Abstract
A virtual root generating method, apparatus, computer device, storage medium and computer program product, the method comprising: obtaining a dental crown model and a tooth root depth, and obtaining projection points according to neck edge points of the dental crown model; obtaining a root shape edge line according to the projection point and the root depth; obtaining a tooth root curved surface according to the tooth root shape edge line; generating a virtual tooth root according to the tooth root curved surface. According to the method, the edge line of the shape of the tooth root is determined through four parameters, and then the curve cluster is generated through projection points, and the curve cluster is used for generating the curved surface of the tooth root, so that a virtual tooth root with high accuracy can be obtained, and the gap between the virtual tooth root and the real tooth root is greatly reduced. In the design stage of the correction scheme, a finished tooth model with a dental crown and a dental root can be provided for doctors, so that the movement process of the dental crown and the dental root is accurately simulated in the design process of the correction scheme, and the reliability and the success rate of the correction scheme are improved.
Description
Technical Field
The present application relates to the field of orthodontic technology, and in particular, to a method, an apparatus, a computer device, a storage medium, and a computer program product for generating a virtual tooth root.
Background
The traditional orthodontic method adopts a fixed bracket appliance adhered to teeth, and has the defects that the steel wire is exposed to affect the beauty, the steel wire is easy to damage mucous membrane in the oral cavity, the gap between the steel wire and the teeth is inconvenient to clean, and bacterial plaque is easy to breed to cause tooth demineralization and color change. To overcome these shortcomings of fixed bracket appliances, bracket-less invisible appliances have emerged. The invisible appliance is made of safe elastic transparent high polymer materials, can be automatically taken off and worn by patients, and can normally maintain oral hygiene. And the invisible appliance is used without adhering a bracket and adjusting an arch wire on the dental crown of a patient, so that the clinical operation is greatly simplified.
In the existing invisible appliance, a dental plaster model or an impression of a patient is firstly scanned through optics or CT, or a current dental state image of the patient is scanned and acquired in a straight interface, so that a dental digital model of the patient is established. The final orthodontic state is then manually determined by the practitioner from the patient's original dental state, and a plurality of intermediate dental states are then obtained by means of computer-aided design, thereby producing a series of concealed appliances, each concealed appliance corresponding to a different stage of the patient's orthodontic. It follows that obtaining the original dental state of a patient is a necessary condition for designing an appliance. The doctor moves some teeth empirically according to the original tooth state of the patient, thereby achieving the target dentition for correction.
However, at present, only the crown data of the patient can be obtained from the original tooth state of the patient, each tooth is composed of an exposed crown and a tooth root embedded in an alveolar bone, and a CT image can obtain an image of the tooth root, but the CT image is two-dimensional image data, and a three-dimensional model of the tooth root of the patient cannot be directly obtained. In the intraoral scanning mode, only three-dimensional image data of the dental crowns of the patients can be obtained, but the dental roots cannot be scanned. However, in clinic, there is often no overlap or a moving gap between the crowns, but the tooth roots may be abutted or even abutted, and if the crowns are moved, the adjacent tooth roots will interfere.
In the prior art, a virtual tooth root is generated through a computer algorithm to replace an actual tooth root, however, a large gap exists between the virtual tooth root generated through the method and the actual tooth root, so that the accuracy of the correction plan is greatly affected. Based on this, a virtual root generating method, apparatus, computer device, computer readable storage medium and computer program product are proposed to solve the above-mentioned problems.
Disclosure of Invention
In view of the foregoing, it is desirable to provide a virtual root generating method, apparatus, computer device, computer readable storage medium, and computer program product that can improve the production efficiency and accuracy of an invisible appliance.
In a first aspect, the present application provides a method of generating a virtual root, the method comprising:
obtaining a dental crown model and a tooth root depth, and obtaining projection points according to neck edge points of the dental crown model;
obtaining a root shape edge line according to the projection point and the root depth;
obtaining a tooth root curved surface according to the tooth root shape edge line;
generating a virtual tooth root according to the tooth root curved surface.
In one embodiment, deriving the projection points from the neck margin points of the crown model includes:
extracting a neck margin line of the dental crown model, and collecting neck margin points on the neck margin line;
taking the direction of the tooth crown pointing to the root tip of the tooth root as the axial direction of the tooth root, and calculating the lowest point of the neck margin point along the axial direction of the tooth root;
constructing a plane according to the axial direction of the tooth root and the lowest point;
and projecting the neck edge point onto a plane to obtain a projection point.
In one embodiment, deriving a root shape edge line from the proxels and the root depths includes:
calculating the center point of the projection point;
calculating the distance between the center point and each projection point, and acquiring the farthest distance and the farthest point;
the method comprises the steps that a locating point is obtained according to the furthest point, the locating point has a first preset distance with the furthest point in the direction of pointing to the center point of the furthest point, and has a second preset distance with the furthest point in the direction parallel to the axial direction of the tooth root;
acquiring a first tangential vector according to the farthest point and acquiring a second tangential vector according to the locating point;
obtaining a root shape edge line according to the furthest point, the first tangential vector, the locating point and the second tangential vector;
in one embodiment, the obtaining the first tangential vector from the furthest point and the obtaining the second tangential vector from the locating point comprises:
constructing a first vector passing through the furthest point according to the axial direction of the tooth root with a preset length;
constructing a second vector passing through the locating point according to the direction of pointing the farthest point to the central point and the preset length;
the first tangential vector and the first vector have a first preset angle therebetween, and the second tangential vector and the second vector have a second preset angle therebetween.
In one embodiment, obtaining a root surface from a root shape edge line comprises:
calculating a first contraction coefficient and a second contraction coefficient according to the root shape edge line;
each projection point is contracted according to the first contraction coefficient and the second contraction coefficient to obtain a point set, and the point set is fitted to obtain a curve cluster;
and obtaining a tooth root curved surface according to the curve cluster and the tooth root shape edge line.
In one embodiment, calculating the first and second coefficients of contraction from the root shape edge line comprises:
constructing a first straight line and a second straight line, wherein the first straight line is a straight line with a central point and a farthest point, and the second straight line is a straight line which is parallel to the axial direction of the tooth root and passes through the central point;
sampling the edge line of the tooth root shape by sampling points, and calculating the distance from each sampling point to the first straight line and the second straight line;
the first contraction coefficient is the ratio of the distance from the sampling point to the second straight line to the farthest distance, and the second contraction coefficient is the distance from the sampling point to the first straight line.
In one embodiment, generating a virtual root from a root surface includes: splicing one end of the curved surface of the tooth root with the crown model, and filling the other end of the curved surface of the tooth root with the hole to obtain the virtual tooth root.
In a second aspect, the present application also provides a virtual root generating apparatus, the apparatus comprising:
the obtaining module is used for obtaining the dental crown model and the tooth root depth and obtaining projection points according to the neck margin points of the dental crown model;
the first calculation module is used for obtaining a root shape edge line according to the projection point and the root depth;
the second calculation module is used for obtaining a tooth root curved surface according to the tooth root shape edge line;
and the synthesis module is used for generating a virtual tooth root according to the tooth root curved surface.
In a third aspect, the present application also provides a computer device comprising a memory storing a computer program and a processor implementing the following steps when executing the computer program:
obtaining a dental crown model and a tooth root depth, and obtaining projection points according to neck edge points of the dental crown model;
obtaining a root shape edge line according to the projection point and the root depth;
obtaining a tooth root curved surface according to the tooth root shape edge line;
generating a virtual tooth root according to the tooth root curved surface.
In a fourth aspect, the present application also provides a computer readable storage medium having stored thereon a computer program which when executed by a processor performs the steps of:
obtaining a dental crown model and a tooth root depth, and obtaining projection points according to neck edge points of the dental crown model;
obtaining a root shape edge line according to the projection point and the root depth;
obtaining a tooth root curved surface according to the tooth root shape edge line;
generating a virtual tooth root according to the tooth root curved surface.
In a fifth aspect, the application also provides a computer program product comprising a computer program which, when executed by a processor, performs the steps of:
obtaining a dental crown model and a tooth root depth, and obtaining projection points according to neck edge points of the dental crown model;
obtaining a root shape edge line according to the projection point and the root depth;
obtaining a tooth root curved surface according to the tooth root shape edge line;
generating a virtual tooth root according to the tooth root curved surface.
The virtual tooth root generating method, the device, the computer equipment, the storage medium and the computer program product firstly obtain projection points on a plane through neck edge points on the neck edge line of a tooth crown model, determine four parameters by combining the tooth root depth, and then calculate and generate tooth root shape edge lines, namely, determine the outer contour line of the tooth root side edge; and then sampling according to the tooth root shape edge line and calculating a contraction coefficient, contracting the projection points according to the contraction coefficient to obtain a point set, forming the peripheral outline of the tooth root by the point distribution in the point set, fitting the points to obtain a curve cluster, obtaining a tooth root curved surface by combining the tooth root shape edge line, and finally generating a complete virtual tooth root. The edge line of the tooth root shape is determined through four parameters, and then a curve cluster is generated through projection points, and a tooth root curved surface is generated through the curve cluster, so that a virtual tooth root with high accuracy can be obtained, and the gap between the virtual tooth root and a real tooth root is greatly reduced. In the design stage of the correction scheme, a finished tooth model with a dental crown and a dental root can be provided for doctors, so that the movement process of the dental crown and the dental root is accurately simulated in the design process of the correction scheme, and the reliability and the success rate of the correction scheme are improved.
Drawings
FIG. 1 is a flowchart illustrating a method for generating virtual root in accordance with an embodiment of the present application;
FIG. 2 is a schematic diagram of a crown model and the lowest points among the cervical margin points in a virtual root generating method according to an embodiment of the present application;
FIG. 3 is a schematic diagram of a construction plane in a virtual root generating method according to an embodiment of the present application;
FIG. 4 is a schematic view of a projection of a cervical margin point onto a plane to obtain a projection point in a virtual root generating method according to an embodiment of the application;
FIG. 5 is a schematic diagram of anchor points in a virtual root generating method according to an embodiment of the application;
FIG. 6 is a schematic diagram of a root shape edge line constructed in a virtual root generation method according to an embodiment of the application;
fig. 7 is a schematic diagram of constructing a first tangential vector and a second tangential vector in a virtual root generating method according to an embodiment of the application.
FIG. 8 is a schematic diagram of constructing a first straight line and a second straight line in a virtual root generating method according to an embodiment of the application;
FIG. 9 is a schematic diagram of a point to be fitted obtained by shrinking a projection point according to a root shape edge line in a virtual root generating method according to an embodiment of the application;
FIG. 10 is a schematic view of a root surface in a virtual root generation method according to an embodiment of the application;
FIG. 11 is a schematic diagram of a virtual root generation method configured to splice the top of a root surface in accordance with an embodiment of the application;
fig. 12 is a schematic diagram of a complete tooth obtained by constructing a hole filling for the bottom of a curved root surface in a virtual root generating method according to an embodiment of the application.
Detailed Description
In order that the above objects, features and advantages of the application will be readily understood, a more particular description of the application will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The present application may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the application, whereby the application is not limited to the specific embodiments disclosed below.
In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
In the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.
In the present application, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.
It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.
Referring to fig. 1, fig. 1 is a flowchart showing an overall method of generating virtual root in accordance with an embodiment of the present application, the method includes steps 100 to 400:
s100, acquiring a dental crown model and a tooth root depth, and obtaining projection points according to neck margin points of the dental crown model (see fig. 4).
A complete tooth message includes a crown located above the gums and a root wrapped inside the gums. In this embodiment, the root area is divided into three parts, the first part is a root surface (see fig. 10, which will be described in detail later), the second part is a portion to be spliced between the root surface top and the crown (see fig. 11), and the third part is a portion to be hole-filled at the root surface bottom (see fig. 12). Namely, after the curved surface of the tooth root is calculated, the curved surface of the tooth root is spliced and hole-filling is carried out, so that a complete tooth can be obtained, the moving process of the tooth crown and the tooth root can be accurately simulated, and the tooth root collision in the tooth moving process is avoided.
Specifically, the dental crown data can be obtained by directly performing three-dimensional scanning from the oral cavity of a patient through an oral scanner, or by scanning a dental plaster model or impression of the patient through optics and CT, then dividing the teeth, and then performing adjacent surface repair, so that a dental crown model of a single tooth can be obtained. The projection points are used for determining the edge shape, the top contour and the bottom contour of the curved surface of the tooth root, so that the complete tooth root is obtained.
And S200, obtaining a root shape edge line according to the projection points and the root depth (see fig. 6).
Specifically, a first parameter is determined by the proxel, a second parameter is determined by the first parameter, and a third parameter and a fourth parameter are determined by the first parameter and the second parameter, respectively. By combining the four parameters to influence and determine a unique tooth root shape edge line, the tooth root profile shape which is well matched with the tooth crown can be obtained, so that the finally generated virtual tooth root can be more approximate to the real tooth root.
S300, obtaining a tooth root curved surface according to the tooth root shape edge line (see fig. 10).
Specifically, the curved surface is composed of a plurality of curves, the root shape edge line only determines one curve, and other curves are determined through the root shape edge line and the projection points, so that the root curved surface with the uniquely determined shape can be obtained.
S400, generating a virtual tooth root according to the tooth root curved surface (see fig. 12).
The obtained curved surface of the tooth root is only a part of the tooth root area, and the curved surface of the tooth root is further spliced and hole-repaired to obtain the complete virtual tooth root.
By the method, the virtual tooth root with higher precision can be obtained, and the gap between the virtual tooth root and the real tooth root is greatly reduced. In the design stage of the correction scheme, a finished tooth model with a dental crown and a dental root can be provided for doctors, so that the movement process of the dental crown and the dental root is accurately simulated in the design process of the correction scheme, and the reliability and the success rate of the correction scheme are improved.
Referring to fig. 2, 3 and 4, S100 acquires a crown model and a root depth, and obtains a projection point according to a cervical margin point of the crown model, comprising the steps of:
s101, extracting a neck margin line of the dental crown model, and collecting neck margin points on the neck margin line.
In particular, the tooth crown and the tooth root are demarcated by a dental neck, and the demarcated is an arc-shaped curve which is defined as a cervical line, and the cervical line in the digital model consists of discrete ordered point arrays, and the points are called cervical points.
S102, taking the direction of the crown pointing to the root tip of the tooth root as the axial z of the tooth root, and calculating the lowest point P of the cervical margin point along the axial direction of the tooth root O 。
S103, according to the axial direction z of the tooth root and the lowest point P O A plane S is constructed.
Specifically, by constructing the plane S in the dot french, the construction method is as follows: p (P) 0 The point coordinates are (x 0 ，y 0 ，z 0 ) Normal vector in root axial directionThe plane S equation is derived from the point french: a (x-x) 0 )+b(y-y 0 )+c(z-z 0 )＝0。
S104, projecting the neck edge point onto the plane S to obtain a projection point. The proxels form the contour shape of the root surface top.
Referring to fig. 4, 5, 6 and 7, S200 of obtaining a root shape edge line according to a proxel and a root depth includes the steps of:
s201, calculating a center point O of the projection point.
Specifically, the center point O coordinate is calculated by means of a mean algorithm: the coordinates of the projection point are (x 1 ，y 1 )、(x 2 ，y 2 )…(x n ，y n ) The center point O coordinate isThe depth of the tooth root is the length from the center point O to the root tip, the depth of the tooth root is specified by a user, and the depth of the tooth root of an adult is 8-15mm.
S202, calculating the distance between the center point O and each projection point, and obtaining the farthest distance d 1 And the furthest point p 1 。
Specifically, the distance from each projection point to the center point O may be calculated using the euclidean distance, where d=sqrt ((x) i -x 0 ) 2 +(y i -y 0 ) 2 ). Distance d furthest 1 For after calculationThe most distant point p is the contraction coefficient required for obtaining the curved surface of tooth root 1 For use as a first parameter in calculating the root shape edge line.
S203, according to the furthest point p 1 Obtaining a locating point p 2 Setpoint p 2 At the furthest point p 1 In the direction pointing towards the centre point O and furthest away from point p 1 Having a first preset distance L 1 In a direction parallel to the root axis z and at the furthest point p 1 With a second preset distance L 2 。
Specifically, the point p is located 2 And the furthest point p 1 The distance between them is determined from projections in both directions, whereby the setpoint p can be determined 2 Is a position of (c). Set setpoint p 2 And the furthest point p 1 The connection line of (2) is L, then the first preset distance L 1 Is L at the furthest point p 1 A projection distance from the central point O to a straight line, a second preset distance L 2 Is the projected distance of L on a straight line parallel to the root axis z.
Preferably, the furthest point p 1 Translating a first preset distance L along a direction pointing to the center point O 1 A first preset distance L 1 At the furthest distance d 1 Is a times larger than the above. A first preset distance L 1 The width of the root surface bottom can be determined, namely, the larger the value A is, the L is 1 The closer to the center point, the narrower the root surface bottom, the smaller the value A, then L 1 The closer to the furthest point p 1 The wider the root surface bottom, the more arbitrary the A is, in this example, the A is 0.5. Determining a first preset distance L 1 Then translate a second preset distance L along the direction pointing to the axial direction of the tooth root 2 A second preset distance L 2 Is B times the depth of the tooth root. A second preset distance L 2 The length of the root surface can be determined, that is, the larger the value B, the longer the length of the root surface, the smaller the value B, the smaller the length of the root surface, and B is any value, and in this embodiment, B is 0.67. According to the furthest point p 1 A first preset distance L 1 And a second preset distance L 2 The anchor point p can be obtained 2 Setpoint p 2 Second for computing root shape edge lineParameters.
S204, according to the furthest point p 1 Acquiring a first tangential vectorAccording to the positioning point p 2 Obtaining second tangential +.>First tangential->Second tangential->Has a direction and a length, a first tangential +.>Through the furthest point, the second tangential vector +.>Through the positioning point, the first tangential->As a third parameter for calculating the root shape edge line, the second tangential vector +.>As a fourth parameter for calculating the root shape edge line.
S205, according to the furthest point p 1 First tangentialSetpoint p 2 Second tangential ∈ ->Obtaining the root shape edge line.
Specifically, the root shape edge line is obtained by calculating a Hermite curve, wherein the Hermite curve is three obtained by giving two endpoints and two endpoint vectorsA secondary curve. In this embodiment, two end points of the root shape edge line are the farthest points p 1 And setpoint p 2 The vectors of the two end points are first tangential vectorsAnd a second tangential ∈ ->Through the furthest point p 1 Positioning point p 2 First tangential->Second tangential ∈ ->The Hermite curve can be obtained through calculation, the curve is the tooth root shape edge line, and the tooth root shape edge line obtained through calculation of the four parameters can simulate the virtual tooth root with accuracy closer to that of a real tooth root.
In some embodiments, S204 is based on the furthest point p 1 Acquiring a first tangential vectorAccording to the positioning point p 2 Obtaining a second tangential vectorThe method comprises the following steps:
s2041, according to the axial direction z of the tooth root, the tooth root passes through the furthest point p in a preset length configuration 1 Is the first vector of (2)
The direction is determined, the length is definite, and the determined vector can be obtained. Specifically, a first vectorIs the root axial direction z, the starting point is the furthest point p 1 The preset length is a positioning pointp 2 And the furthest point p 1 C times the distance between them, C can be any number between 0.2 and 1.0, in this example C is 0.7. The change of the preset length can influence the length of the vector, so that the calculation of the Hermite curve can be influenced, the shape of the edge line of the tooth root shape can be finally changed, and an operator can determine the specific value of C according to the simulated shape effect.
S2042 according to the furthest point p 1 Pointing in the direction of the central point O, passing through the positioning point p with a preset length configuration 2 Is the second vector of (2)Is>C is 0.4, and a second vector is determined according to the direction and the preset length>Second vector->Starting point is anchor point p 2 。
S2043 first tangentialIs +_associated with the first vector>With a first preset angle theta therebetween 1 Second tangential->And a second vector->With a second preset angle theta therebetween 2 。
Specifically, by a first preset angle θ 1 Determining a first tangentThrough a second preset angle theta 2 Determining the second tangential +.>Is the first tangential->And a second tangential ∈ ->The direction of (2) also affects the calculation of the Hermite curve, the first predetermined angle θ 1 And a second preset angle theta 2 Can be any angle value between 0 and 60 degrees, in the embodiment, theta 1 、θ 2 45 degrees, the first vector is +.>The first tangential +.>Second vector +.>A second tangential +.>Specifically, the first tangential->Is the cut of the Hermite curve at the furthest point, the second tangent vector +.>Is the cut of the Hermite curve at the locating point.
Referring to fig. 8, 9 and 10, S300 includes the following steps of:
s301, calculating a first shrinkage coefficient and a second shrinkage coefficient according to the root shape edge line. The root surface top to bottom tends to taper, and the first shrinkage factor and the second shrinkage factor are calculated to determine the shrinkage amplitude of the root surface from top to bottom, thereby determining the shape of the entire root surface from top to bottom.
S302, each projection point is shrunk according to the first shrinkage coefficient and the second shrinkage coefficient to obtain a point set, and the point set is fitted to obtain a curve cluster.
Specifically, the point set is a grid point to be fitted, and each column of the grid point is interpolated to obtain a plurality of spline curves. The shape of the tooth root curved surface edge line is only determined, and the outer ring profile of the whole tooth root curved surface can be obtained by contracting each projection point, so that the shape of the whole tooth root curved surface is determined.
S303, obtaining a curved surface of the tooth root according to the curve cluster and the edge line of the shape of the tooth root. Interpolation of curve clusters and root shape edge lines may enable a shape-determined root surface to be obtained.
In some embodiments, S301 calculating the first and second coefficients of contraction from root shape edge lines comprises the steps of:
s3011, constructing a first straight line P and a second straight line Q, wherein the first straight line P is a central point O and a farthest point P 1 The second straight line Q is a straight line which is parallel to the axial direction z of the tooth root and passes through the center point O.
S3012, sampling the edge line of the tooth root shape by sampling points, and calculating the distance between each sampling point and the first straight line P and the second straight line Q. The distance of each sampling point to the first straight line P and the second straight line Q may be calculated by the euclidean distance.
S3013, the first contraction coefficient is the ratio of the distance from the sampling point to the second straight line to the farthest distance, and the second contraction coefficient is the distance from the sampling point to the first straight line.
Referring to fig. 11 and 12, S400 includes: splicing the top of the curved surface of the tooth root with the crown model, and filling the bottom of the curved surface of the tooth root with holes to obtain the virtual tooth root.
Specifically, the root curved surface is gridded, and when the root curved surface is gridded, the top boundary parameter, for example, 0.0, is not sampled, and after crossing a certain step, for example, step value/arc length, sampling is started, so that a splicing space is reserved. Splicing the top of the meshed tooth root curved surface with the tooth crown model, repairing the bottom of the meshed tooth root curved surface, and repairing the bottom by adopting a method based on sheet energy to obtain a complete tooth root area. And the generated tooth root area is subjected to fairing treatment, so that the fairing treatment can be performed in a Laplace mode, and finally, a complete and relatively accurate virtual tooth root model can be obtained, and a doctor can conveniently perform tooth orthodontic planning design.
Finally, the whole implementation process is described:
inputting a crown model, a tooth root axial z and a tooth root depth, wherein the tooth root depth is 8mm; searching a neck margin point and a neck margin line of the dental crown model; searching the lowest point P at the lower end in the cervical margin point along the axial direction z of the tooth root O The method comprises the steps of carrying out a first treatment on the surface of the At the lowest point P O Constructing a lowest plane S in the axial direction z of the tooth root; projecting the neck edge point onto the lowest plane S, and calculating a mean coordinate point of the projection point as a center point O; traversing the projection points, calculating the distance between each projection point and the central point O by adopting Euclidean distance, and recording the furthest point P furthest from the central point O 1 And the furthest point P 1 The distance of (2) is denoted as the furthest distance d 1 The method comprises the steps of carrying out a first treatment on the surface of the The furthest point p 1 Translating 0.5 times of the longest distance along the direction pointing to the center point O, translating 0.67 times of the depth of the tooth root along the direction pointing to the axial direction of the tooth root, and recording a low-end positioning point p 2 The method comprises the steps of carrying out a first treatment on the surface of the Constructing the furthest point p with the root axial direction z as the direction and 0.7 as the length 1 Is a first tangent of (2)At the furthest point p 1 The direction pointing to the center point O is the direction, and the positioning point p is constructed with the length of 0.4 2 Second tangential ∈of (2)>At the furthest point p 1 First tangential->Setpoint p 2 Second tangential ∈ ->And interpolating to construct a Hermite curve, thus obtaining the tooth root shape edge line.
Build through center point O and furthest point p 1 Constructing a vertical line Q parallel to the root axial direction z and passing through the center point O; uniformly sampling on a Hermite curve, calculating the distance between a sampling point and a horizontal straight line P and a vertical straight line Q, and calculating the distance between the sampling point and the vertical straight line Q and the farthest distance d 1 Taking the ratio of the sampling point to the horizontal straight line P as a first contraction coefficient and taking the distance from the sampling point to the horizontal straight line P as a second contraction coefficient; sampling all projection points according to the first contraction coefficient and the second contraction coefficient to obtain grid points to be fitted; interpolation is carried out on each column of the grid points to obtain a cluster of spline curves; interpolating the cluster curve to obtain a skin curved surface, namely obtaining a tooth root curved surface; and (3) splicing and hole filling are carried out on the curved surfaces of the tooth roots to obtain complete tooth root areas, wherein the depth of the hole filling is slightly less than 0.33 time of the depth of the tooth roots.
It should be understood that, although the steps in the flowcharts related to the embodiments described above are sequentially shown as indicated by arrows, these steps are not necessarily sequentially performed in the order indicated by the arrows. The steps are not strictly limited to the order of execution unless explicitly recited herein, and the steps may be executed in other orders. Moreover, at least some of the steps in the flowcharts described in the above embodiments may include a plurality of steps or a plurality of stages, which are not necessarily performed at the same time, but may be performed at different times, and the order of the steps or stages is not necessarily performed sequentially, but may be performed alternately or alternately with at least some of the other steps or stages.
Based on the same inventive concept, the embodiment of the application also provides a virtual root generating device for realizing the virtual root generating method. The implementation of the solution provided by the device is similar to the implementation described in the above method, so the specific limitations in the embodiments of one or more virtual root generating devices provided below may be found in the above-mentioned laying of a virtual root generating method, and are not described here in detail.
In some embodiments, a virtual root generating apparatus is provided, including an acquisition module, a first calculation module, a second calculation module, and a synthesis module, wherein:
the acquisition module is used for acquiring the crown model and the tooth root depth and obtaining projection points according to the neck margin points of the crown model.
And the first calculation module is used for obtaining a root shape edge line according to the projection point and the root depth.
And the second calculation module is used for obtaining a tooth root curved surface according to the tooth root shape edge line.
And the synthesis module is used for generating a virtual tooth root according to the tooth root curved surface.
In some embodiments, the obtaining module obtains the projection point according to the crown model and the root depth and according to a crown model neck margin point, including: extracting a neck margin line of the dental crown model, and collecting neck margin points on the neck margin line; taking the direction of the tooth crown pointing to the root tip of the tooth root as the axial direction of the tooth root, and calculating the lowest point of the neck margin point along the axial direction of the tooth root; constructing a plane according to the axial direction of the tooth root and the lowest point; and projecting the neck edge point onto a plane to obtain a projection point.
In some embodiments, the first computing module obtains a root shape edge line from the proxels and the root depths, comprising: calculating the center point of the projection point; calculating the distance between the center point and each projection point, and acquiring the farthest distance and the farthest point; the method comprises the steps that a locating point is obtained according to the furthest point, the locating point has a first preset distance with the furthest point in the direction of pointing to the center point of the furthest point, and has a second preset distance with the furthest point in the direction parallel to the axial direction of the tooth root; acquiring a first tangential vector according to the farthest point and acquiring a second tangential vector according to the locating point; and obtaining the root shape edge line according to the furthest point, the first tangential vector, the locating point and the second tangential vector.
In some embodiments, the first computing module obtains a first tangent vector from the furthest point and obtaining a second tangent vector from the locating point comprises: constructing a first vector passing through the furthest point according to the axial direction of the tooth root with a preset length; constructing a second vector passing through the locating point according to the direction of pointing the farthest point to the central point and the preset length; the first tangential vector and the first vector have a first preset angle therebetween, and the second tangential vector and the second vector have a second preset angle therebetween.
In some embodiments, the second computing module obtains a root surface from a root shape edge line, comprising: calculating a first contraction coefficient and a second contraction coefficient according to the root shape edge line; each projection point is contracted according to the first contraction coefficient and the second contraction coefficient to obtain a point set, and the point set is fitted to obtain a curve cluster; and obtaining a tooth root curved surface according to the curve cluster and the tooth root shape edge line.
In some embodiments, the second calculation module calculating the first and second coefficients of contraction from the root shape edge line comprises: constructing a first straight line and a second straight line, wherein the first straight line is a straight line with a central point and a farthest point, and the second straight line is a straight line which is parallel to the axial direction of the tooth root and passes through the central point; sampling the edge line of the tooth root shape by sampling points, and calculating the distance from each sampling point to the first straight line and the second straight line; the first contraction coefficient is the ratio of the distance from the sampling point to the second straight line to the farthest distance, and the second contraction coefficient is the distance from the sampling point to the first straight line.
In some embodiments, the synthesizing module generates the virtual root from the root surface, comprising: splicing the top of the curved surface of the tooth root with the crown model, and filling the bottom of the curved surface of the tooth root with holes to obtain the virtual tooth root.
The various modules in the virtual root generating apparatus described above may be implemented in whole or in part by software, hardware, and combinations thereof. The above modules may be embedded in hardware or may be independent of a processor in the computer device, or may be stored in software in a memory in the computer device, so that the processor may call and execute operations corresponding to the above modules.
In one embodiment, a computer device is provided, which may be a server. The computer device includes a processor, a memory, an Input/Output interface (I/O) and a communication interface. The processor, the memory and the input/output interface are connected through a system bus, and the communication interface is connected to the system bus through the input/output interface. Wherein the processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The database of the computer device is used for storing data related to tooth models (crowns, roots, etc.). The input/output interface of the computer device is used to exchange information between the processor and the external device. The communication interface of the computer device is used for communicating with an external terminal through a network connection. The computer program is executed by a processor to implement a virtual root generating method.
In some embodiments, a computer device is provided, comprising a memory and a processor, the memory having stored therein a computer program, the processor implementing the steps of the method embodiments described above when the computer program is executed.
In some embodiments, a computer-readable storage medium is provided, on which a computer program is stored which, when executed by a processor, carries out the steps of the method embodiments described above.
In some embodiments, a computer degree product is provided comprising a computer program which, when executed by a processor, implements the steps of the method embodiments described above.
Those skilled in the art will appreciate that implementing all or part of the above described methods may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, database, or other medium used in embodiments provided herein may include at least one of non-volatile and volatile memory. The nonvolatile Memory may include Read-Only Memory (ROM), magnetic tape, floppy disk, flash Memory, optical Memory, high density embedded nonvolatile Memory, resistive random access Memory (ReRAM), magnetic random access Memory (Magnetoresistive Random Access Memory, MRAM), ferroelectric Memory (Ferroelectric Random Access Memory, FRAM), phase change Memory (Phase Change Memory, PCM), graphene Memory, and the like. Volatile memory can include random access memory (Random Access Memory, RAM) or external cache memory, and the like. By way of illustration, and not limitation, RAM can be in the form of a variety of forms, such as static random access memory (Static Random Access Memory, SRAM) or dynamic random access memory (Dynamic Random Access Memory, DRAM), and the like. The databases referred to in the embodiments provided herein may include at least one of a relational database and a non-relational database. The non-relational database may include, but is not limited to, a blockchain-based distributed database, and the like. The processor referred to in the embodiments provided in the present application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic unit, a data processing logic unit based on quantum computing, or the like, but is not limited thereto.
The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The foregoing examples illustrate only a few embodiments of the application and are described in detail herein without thereby limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of the application should be assessed as that of the appended claims.
Claims (8)
1. A method of virtual root generation, the method comprising:
obtaining a crown model and a tooth root depth, and obtaining projection points according to neck margin points of the crown model;
obtaining a root shape edge line according to the projection point and the root depth, wherein the root shape edge line comprises: calculating the central point of the projection point; calculating the distance between the central point and each projection point, and obtaining the furthest distance and the furthest point; acquiring a positioning point according to the furthest point, wherein the positioning point has a first preset distance from the furthest point in the direction of pointing to a central point of the furthest point, and has a second preset distance from the furthest point in the direction parallel to the axial direction of the tooth root; acquiring a first tangential vector according to the furthest point, and acquiring a second tangential vector according to the locating point; obtaining the root shape edge line according to the furthest point, the first tangential vector, the locating point and the second tangential vector;
obtaining a root surface according to the root shape edge line, which comprises the following steps: calculating a first contraction coefficient and a second contraction coefficient according to the root shape edge line; each projection point is contracted according to the first contraction coefficient and the second contraction coefficient to obtain a point set, and the point set is fitted to obtain a curve cluster; obtaining the curved surface of the tooth root according to the curve cluster and the edge line of the shape of the tooth root;
and generating a virtual tooth root according to the tooth root curved surface.
2. The virtual root generating method according to claim 1, wherein the obtaining a projection point from a cervical margin point of the crown model comprises:
extracting a neck margin line of the dental crown model, and collecting neck margin points on the neck margin line;
taking the direction of the dental crown pointing to the root tip of the dental root as the axial direction of the dental root, and calculating the lowest point of the neck margin point along the axial direction of the dental root;
constructing a plane according to the root axis and the nadir;
and projecting the neck edge point onto the plane to obtain a projection point.
3. The virtual root generating method according to claim 1, wherein the obtaining a first tangential vector from the furthest point and a second tangential vector from the locating point comprises:
constructing a first vector passing through the furthest point with a preset length according to the axial direction of the tooth root;
constructing a second vector passing through the locating point according to the direction of the furthest point to the central point and the preset length;
the first tangential vector and the first vector have a first preset angle therebetween, and the second tangential vector and the second vector have a second preset angle therebetween.
4. The virtual root generating method according to claim 1, wherein the calculating a first contraction coefficient and a second contraction coefficient from the root shape edge line comprises:
constructing a first straight line and a second straight line, wherein the first straight line is a straight line where the center point and the farthest point are located, and the second straight line is a straight line which is parallel to the axial direction of the tooth root and passes through the center point;
sampling the root shape edge line by sampling points, and calculating the distance from each sampling point to the first straight line and the second straight line;
the first contraction coefficient is the ratio of the distance from the sampling point to the second straight line to the farthest distance, and the second contraction coefficient is the distance from the sampling point to the first straight line.
5. The virtual root generating method according to claim 1, wherein the generating a virtual root from the root surface comprises: and splicing one end of the curved surface of the tooth root with the dental crown model, and repairing the other end of the curved surface of the tooth root to obtain the virtual tooth root.
6. An apparatus for generating virtual roots, wherein the apparatus generates virtual roots by using the steps of the method for generating virtual roots according to claim 1.
7. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor implements the steps of the method of any one of claims 1 to 5 when the computer program is executed.
8. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, implements the steps of the method of any of claims 1 to 5.
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