CN113855291B

CN113855291B - Implant auxiliary planning method and device, electronic equipment and storage medium

Info

Publication number: CN113855291B
Application number: CN202111449199.2A
Authority: CN
Inventors: 王迎智; 董先公; 张二虎
Original assignee: Jixian Artificial Intelligence Co Ltd
Current assignee: Jixian Artificial Intelligence Co Ltd
Priority date: 2021-12-01
Filing date: 2021-12-01
Publication date: 2022-02-22
Anticipated expiration: 2041-12-01
Also published as: CN113855291A

Abstract

The invention provides an implant aided planning method and device, electronic equipment and a storage medium. The method comprises the following steps: the method comprises the steps of obtaining an initial implantation planning line on a two-dimensional dental arch curved surface image of a target object, determining a target protrusion angle of a target implant according to protrusion angles of adjacent teeth, determining an entry point candidate line on an oral cavity CBCT image according to the variation of pixel values on the initial implantation planning line, determining the entry point position of the target implant according to the variation of the pixel values on the entry point candidate line, determining the tip position of the implant, determining an implant stress influence area in the oral cavity CBCT image according to the entry point position and the tip position, and adjusting the entry point position and the tip position according to the pixel values. The method has the advantages that the proper anterior protruding angle is automatically searched, so that the time for planning and adjusting by a doctor is shortened, the doctor is prompted to plan the implant based on the analysis of the stress affected area of the implant, and the position of the tip position is adjusted, so that the doctor is helped to quickly and accurately plan the final planting position of the target implant.

Description

Implant auxiliary planning method and device, electronic equipment and storage medium

Technical Field

The invention relates to the technical field of dental implants, in particular to an implant aided planning method, an implant aided planning device, electronic equipment and a storage medium.

Background

The implant is a repairing means for replacing the original lost tooth by driving a metal implant into the alveolar bone. In the planning stage, the arrangement position of the metal implant for replacing the missing tooth needs to be planned. The planning method mainly comprises the steps that a doctor inputs contents into software by utilizing a human-computer interaction interface UI, and the implant is placed at an ideal position.

In the related technology, thick-layer dental arch curved surface planning is adopted, namely, a doctor carries out curved surface reconstruction based on a dental arch curve, and implant implantation position marking is carried out on an obtained thick-layer image. However, this planning method has low precision and needs to be adjusted for many times, which results in a long planning process and a great deal of time and energy consumption for the doctor.

Disclosure of Invention

The embodiment of the invention provides an implant aided planning method, an implant aided planning device, electronic equipment and a storage medium, and aims to solve the technical problems in the background art.

In order to solve the technical problem, the invention is realized as follows:

in a first aspect, an embodiment of the present invention provides an implant aided planning method, where the method includes:

acquiring an initial implantation gauge line on a two-dimensional dental arch curved surface image of a target object, wherein the two-dimensional dental arch curved surface image is obtained by performing curved surface reconstruction based on a CBCT (cone beam computed tomography) image of an oral cavity of the target object;

determining the protrusion angle of adjacent teeth of a target implant in the oral CBCT image of the target object according to the initial implantation gauge line, and determining the target protrusion angle of the target implant according to the protrusion angle of the adjacent teeth;

determining an in-point candidate line of the target implant on the oral CBCT image according to the variation of the pixel values on the initial implant planning line, and determining the position of the in-point of the target implant according to the variation of the pixel values on the in-point candidate line;

determining the tip position of the target implant according to the target anterior eminence angle and the entry point;

and determining an implant stress influence area in the oral CBCT image according to the in-point position and the tip position, and adjusting the in-point position and the tip position according to pixel values in the implant stress influence area.

Optionally, determining an implant force affected area in the oral cavity CBCT image according to the in-point position and the tip position, including:

acquiring a stress-affected area parameter of the target implant, wherein the determination mode of the stress-affected area parameter comprises the following steps: generating a plurality of fitting line segments by using sampling points on a profile edge contour line of the target implant, performing segmentation processing on the profile contour line by using the fitting line segments, and determining stress-affected area parameters corresponding to each segmentation area by using the fitting line segments, wherein the stress-affected area parameters of the target implant comprise stress-affected area parameters corresponding to each segmentation area;

and determining the implant stress influence area in the oral CBCT image according to the in-point position, the tip position and the stress influence area parameters of the target implant.

Optionally, the adjusting the position of the entry point and the position of the tip by pixel values in the force-affected area of the implant includes:

equally dividing the stress affected areas of the implant to obtain a plurality of stress affected sub-areas of the implant, wherein each stress affected sub-area consists of a plurality of pixel points;

determining the pixel value of each pixel point in each stress influence sub-area;

evaluating the supporting capacity of each stress-affected subarea according to the pixel value of each pixel point in each stress-affected subarea;

and adjusting the position of the point of entry and the position of the tip according to the support capability evaluation result.

Optionally, the evaluating the support capability of each sub-area affected by force according to the pixel value of each pixel point in each sub-area affected by force includes:

determining the bone density value corresponding to each pixel point according to the preset corresponding relation between the pixel value and the bone density value;

counting the number of target pixel points in the stress affected sub-area of each implant, wherein the bone density value is greater than a preset bone density value threshold;

and if the number of the target pixel points in any stress-affected sub-area is larger than a preset threshold, determining that the supporting capacity of the stress-affected sub-area meets the requirement.

Optionally, the adjusting the position of the entry point and the position of the tip according to the support capability evaluation result includes:

if the number of the target pixel points in the sub-area of the stress affected area is smaller than a preset threshold value, moving the point-in position and the point-end position for a first preset distance along the opposite direction of the normal direction of the sub-area of the stress affected area, and evaluating the supporting capacity of the sub-area of the stress affected area again;

and if the implant supporting capacity of the subimage in the stress affected area still does not meet the requirement, moving the point-in position and the point-out position by a second preset distance along the opposite direction of the normal direction of the subregion of the stress affected area.

Optionally, determining a protrusion angle of adjacent teeth of the target implant in the CBCT image of the oral cavity of the target subject according to the initial implant planning line, comprising:

acquiring a CBCT local section image of the initial implantation gauge line from the oral CBCT image;

respectively projecting the axes of the adjacent teeth onto the CBCT local section image to obtain the axis projection lines of the adjacent teeth;

and determining the included angle between the axis projection line and the vertical line in the CBCT local section image plane as the anterior eminence angle of the adjacent teeth.

Optionally, determining a target protrusion angle of the target implant from protrusion angles of the adjacent teeth comprises:

and determining the average value of the protrusion angles of the adjacent teeth as the target protrusion angle of the target implant.

Optionally, determining an entry point candidate line on the oral cavity CBCT image according to a variation of the pixel values on the initial planting plan line, including:

determining the pixel value of each pixel point on the initial planting planning line, and determining the pixel value difference between every two adjacent pixel points;

determining any one pixel point of two adjacent pixel points of the maximum value of the pixel value difference value absolute value as an in-point candidate point;

and mapping the in-point candidate point to the CBCT local section image to generate the in-point candidate line.

Optionally, determining the position of the entry point of the target implant according to a variation of pixel values on the entry point candidate line includes:

determining the pixel value of each pixel point on the in-point candidate line, and determining the pixel value difference between every two adjacent pixel points;

determining any one pixel point of two adjacent pixel points with the pixel value difference value being a positive maximum value as a first pixel point;

determining any one pixel point of two adjacent pixel points with the pixel value difference value being a negative maximum value as a second pixel point;

determining the midpoint position of a straight line formed by the first pixel point and the second pixel point, and determining the pixel point closest to the midpoint position as the in-point position of the target implant.

Optionally, the method further comprises:

if the target implant is a lower dental implant, determining the distance between the position of an entry point of the target implant and a lower dental neural tube;

and if the distance between the point-in position of the target implant and the lower dental neural tube is smaller than a preset safety threshold, moving the tip position by a third preset distance along the direction close to the point-in position.

A second aspect of the embodiments of the present invention provides an implant aided planning apparatus, including:

the system comprises an acquisition unit, a planning unit and a planning unit, wherein the acquisition unit is used for acquiring an initial implantation planning line on a two-dimensional dental arch curved surface image of a target object, and the two-dimensional dental arch curved surface image is obtained by performing curved surface reconstruction based on an oral CBCT image of the target object;

a first determining unit, configured to determine a protrusion angle of adjacent teeth of a target implant in an oral CBCT image of the target object according to the initial implantation gauge line, and determine a target protrusion angle of the target implant according to the protrusion angle of the adjacent teeth;

the second determining unit is used for determining an in-point candidate line of the target implant on the oral CBCT image according to the variation of the pixel values on the initial implant planning line and determining the in-point position of the target implant according to the variation of the pixel values on the in-point candidate line;

a third determining unit, configured to determine a tip position of the target implant according to the target anterior eminence angle and the entry point;

and the adjusting unit is used for determining an implant stress influence area in the oral CBCT image according to the position of the entry point and the position of the tip, and adjusting the position of the entry point and the position of the tip through pixel values in the implant stress influence area.

Optionally, the adjusting unit includes:

the first determining module is used for acquiring the parameters of the stress-affected area of the target implant, and the determining mode of the parameters of the stress-affected area comprises the following steps: generating a plurality of fitting line segments by using sampling points on a profile edge contour line of the target implant, performing segmentation processing on the profile contour line by using the fitting line segments, and determining stress-affected area parameters corresponding to each segmentation area by using the fitting line segments, wherein the stress-affected area parameters of the target implant comprise stress-affected area parameters corresponding to each segmentation area;

and the second determination module is used for determining the implant stress influence area in the oral CBCT image according to the in-point position, the tip position and the stress influence area parameters of the target implant.

Optionally, the adjusting unit includes:

the segmentation module is used for equally dividing the stress affected area of the implant to obtain a plurality of stress affected sub-areas of the implant, wherein each stress affected sub-area consists of a plurality of pixel points;

the pixel determining module is used for determining the pixel value of each pixel point in each stress influence sub-area;

the evaluation module is used for evaluating the supporting capacity of each stress influence subarea according to the pixel value of each pixel point in each stress influence subarea;

and the first adjusting module is used for adjusting the position of the point-in and the position of the tip according to the support capability evaluation result.

Optionally, the evaluation module comprises:

the bone density value determining submodule is used for determining the bone density value corresponding to each pixel point according to the preset corresponding relation between the pixel value and the bone density value;

the statistics submodule is used for counting the number of target pixel points in the stress influence sub-area of each implant, wherein the bone density value is greater than a preset bone density value threshold;

and the evaluation submodule is used for determining that the supporting capability of the stress sub-area meets the requirement if the number of the target pixel points in any one stress sub-area is greater than a preset threshold value.

Optionally, the first adjusting module includes:

the first adjusting submodule is used for moving the point-in position and the tip position for a first preset distance along the opposite direction of the normal direction of the sub-area of the stress affected area if the number of the target pixel points in the sub-area of the stress affected area is smaller than a preset threshold value, and evaluating the supporting capacity of the sub-area of the stress affected area again;

and the second adjusting submodule is used for moving the point-in position and the point-out position by a second preset distance along the opposite direction of the normal direction of the sub-area of the stress affected area if the supporting capacity of the implant of the sub-image of the stress affected area still does not meet the requirement.

Optionally, the first determining unit includes:

the sectional image acquisition module is used for acquiring a CBCT local sectional image of the initial implantation gauge line from the oral CBCT image;

the projection module is used for projecting the axes of the adjacent teeth onto the CBCT local section image respectively to obtain the axis projection lines of the adjacent teeth of the implant;

and the determining module is used for determining an included angle between the axis projection line and a vertical line in the CBCT local section image plane as an anterior convex angle of the adjacent teeth.

Optionally, the second determining unit includes:

the first pixel difference determining module is used for determining the pixel value of each pixel point on the initial planting planning line and determining the pixel value difference between every two adjacent pixel points;

an in-point candidate point determining module, configured to determine any one of two adjacent pixel points of a maximum value of the pixel value difference absolute value as an in-point candidate point;

and the in-point candidate line generating module is used for mapping the in-point candidate points to the CBCT local sectional image to generate the in-point candidate lines.

Optionally, the second determining unit includes:

the second pixel difference determining module is used for determining the pixel value of each pixel point on the in-point candidate line and determining the pixel value difference between every two adjacent pixel points;

the first pixel point determining module is used for determining any one pixel point in two adjacent pixel points with the pixel value difference value being a positive maximum value as a first pixel point;

the second pixel point determining module is used for determining any one pixel point in two adjacent pixel points with the pixel value difference value being a negative maximum value as a second pixel point;

and the in-point determining module is used for determining the midpoint position of a straight line formed by the first pixel point and the second pixel point and determining the pixel point closest to the midpoint position as the in-point position of the target implant.

Optionally, the adjusting unit includes: the first judgment module is used for determining the distance between the position of an entry point of the target implant and a lower dental neural tube if the target implant is a lower dental implant;

and the second adjusting module is used for moving the tip position by a third preset distance along the direction close to the point-in position if the distance between the point-in position of the target implant and the lower dental neural tube is less than a preset safety threshold.

A third aspect of the embodiments of the present invention provides an electronic device, including a processor, a communication interface, a memory, and a communication bus, where the processor and the communication interface complete communication between the memory and the processor through the communication bus;

a memory for storing a computer program;

the processor is configured to implement the method steps provided in the first aspect of the embodiment of the present invention when executing the program stored in the memory.

A fourth aspect of the embodiments of the present invention provides a computer-readable storage medium, on which a computer program is stored, which, when executed by a processor, implements the method as set forth in the first aspect of the embodiments of the present invention.

The embodiment of the invention has the following advantages: the method comprises the steps of obtaining an initial planting rule on a two-dimensional dental arch curved surface image of a target object, determining a protrusion angle of adjacent teeth of the target implant according to an oral CBCT image of the target object, and determining a target protrusion angle of the target implant according to the protrusion angle of the adjacent teeth, so that a more appropriate protrusion angle can be automatically found in the planning process, and the time for planning and adjusting by a doctor is saved. Determining an entry point candidate line on the oral cavity CBCT image according to the variation of the pixel values on an initial implantation planning line, determining the entry point position of the target implant according to the variation of the pixel values on the entry point candidate line, determining the tip position of the implant according to the target anterior-projection angle and the entry point position, determining an implant stress affected area in the oral cavity CBCT image according to the entry point position and the tip position, and adjusting the entry point position and the tip position according to the pixel values in the implant stress affected area. Therefore, based on the analysis of the stress affected area of the implant, the prompt of implant planning is carried out on a doctor, and the position of the entry point and the position of the tip are adjusted, so that the doctor is helped to rapidly and accurately plan the final planting position of the target implant.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a flowchart illustrating the steps of an implant aided planning method according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a cross-sectional CBCT image in accordance with an embodiment of the present invention;

figure 3 is a schematic diagram of a CPR development view in an embodiment of the invention;

FIG. 4 is a schematic view of a small dental plate in an embodiment of the present invention;

FIG. 5 is a sagittal view of adjacent teeth in an embodiment of the invention;

FIG. 6 is a schematic diagram illustrating the sub-area division of the force-affected area according to an embodiment of the present invention;

fig. 7 is a schematic block diagram of an implant aided planning apparatus according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the related art, when planning the implant position of an implant, the mainstream method is thick-layer dental arch curved surface planning, that is, a doctor marks the implant position on a thick-layer image obtained by performing curved surface reconstruction based on a dental arch curve, for example, by performing thick-layer cylindrical expansion. However, the thick-layer image is a two-dimensional image generated by a multilayer image through an MIP maximum density projection algorithm, one point on the thick-layer image actually corresponds to one straight line of a three-dimensional space, and head and tail points pointed by a doctor often cannot reflect the protrusion angle of adjacent teeth, so that the precision is low. And secondary adjustment on the three-dimensional image is required, thereby spending a lot of time.

Based on this, the applicant proposes the inventive concept of the present invention: searching adjacent teeth before and after the planned position, determining the external protrusion angle and the origin of the tooth root (namely the tip position of the implant after the implant is implanted) of the target implant, determining the initial implant position, analyzing whether the stress affected area of the implant meets the requirement of the supporting force, finely adjusting the initial implant position, and finally determining the final implant position of the implant.

The embodiment of the invention provides an implant aided planning method, which is suitable for an application scene of implanting an implant by using a dental implant surgery robot. Referring to fig. 1, fig. 1 is a flow chart illustrating steps of an implant aided planning method according to an embodiment of the present invention, the method including:

s101, acquiring an initial implantation gauge line on a two-dimensional dental arch curved surface image of a target object, wherein the two-dimensional dental arch curved surface image is obtained by performing curved surface reconstruction based on an oral CBCT image of the target object.

In the implant planning process of the implant, dental film images of different fault layers can be displayed on a human-computer interaction interface by adjusting the projection position of a CBCT image of a target object (namely a patient). As an example, a first human-computer interaction interface displayed by an upper computer of the dental implant surgery robot at least comprises a first display area and a second display area, wherein the first display area displays a three-dimensional image reconstructed based on a CBCT image, and the second display area displays the CBCT image at a specified projection position; by adjusting the projection position of the oral CBCT image of the target object, the transverse CBCT image shown in FIG. 2 is displayed in the second display area, and the doctor selects the root of each tooth on the transverse CBCT image to generate a sampling curve (shown in FIG. 2); and performing CPR expansion (e.g. thick-layer columnar expansion) on the original CBCT image according to the sampling curve to obtain a two-dimensional dental arch surface map, wherein the effect is shown in figure 3, and a second human-computer interaction interface is called to display the two-dimensional dental arch surface map. The doctor can judge the tooth missing position and the tooth missing condition of the patient on the second man-machine interface and make a corresponding initial planning line as shown by a white line in fig. 3. The initial planning line contains target implant position information and length information at the time of dental implantation. Namely, the doctor draws an initial planting planning line on the two-dimensional dental arch curved surface image, and the initial planning position of the implant can be determined according to the head and tail points of the initial planning line.

Step S102: determining the protrusion angle of the adjacent teeth of the target implant in the oral CBCT image of the target object according to the initial implantation gauge line, and determining the target protrusion angle of the target implant according to the protrusion angle of the adjacent teeth.

Due to the initial marking line made on the two-dimensional dental arch surface graph, after the three-dimensional image is restored, the three-dimensional dental arch surface graph is actually a plane. Thus, there is a range of angular variation per se, i.e. of the anteroposterior angle of the implant. A target protrusion angle, i.e. an optimal planning angle value, of protrusion angle implants of neighboring teeth of the target implant is thus determined in the CBCT image of the oral cavity of the target object according to the initial implantation gauge line. Under the angle, the protrusion angle of the implant and the protrusion angle of the adjacent tooth meet a linear relation, so that the condition that the implant is not attractive due to the fact that the difference distance between the protrusion angle of the implant and the protrusion angle of the adjacent tooth is too large is avoided, and in order to determine the target protrusion angle of the implant, the following steps are specifically adopted for achieving:

step S102-1: and acquiring a CBCT local section image of the initial implantation gauge line from the oral CBCT image.

In this step, on the second human-computer interaction interface, the initial ruled line drawn by the doctor is extended to both sides of the initial ruled line, so as to obtain a CBCT local cross-sectional image corresponding to the extended line in the original CBCT image, and for convenience of description, the image is defined as a local dentition plane, such as the dentition plane image shown in fig. 4, that is, the cross-sectional image in the CBCT image corresponding to the initial ruled line is a dentition plane image. In practical situations, the sectional plane image is not displayed on a human-computer interaction interface, but is processed by the data processing of the upper computer system.

Step S102-2: and respectively projecting the axes of the adjacent teeth onto the CBCT local section image to obtain the axis projection lines of the adjacent teeth.

In this step, the positions of the adjacent teeth of the implant, which are the left and right teeth in the original edentulous position, need to be determined. Firstly, all the remaining teeth are identified in a three-dimensional image of a patient, namely a CBCT image of the oral cavity of the patient through an image segmentation technology, and then two teeth closest to an initial implantation rule are found. Since the tooth is irregular in shape, in order to simplify the calculation, the tooth is approximately ellipsoidally surrounded by an ellipsoid, so that the spatial position of the ellipsoidally adjacent tooth in the three-dimensional image coordinate system can be obtained. The axial lines (white line segments shown in fig. 5) of the oval adjacent teeth are projected to a local small dental film plane (as shown in fig. 4), so that axial line projection lines of the adjacent teeth are obtained, and the number of the axial line projection lines is two because of two adjacent teeth.

Step S102-3: and determining the included angle between the axis projection line and the vertical line in the CBCT local section image plane as the anterior eminence angle of the adjacent teeth.

In this step, a plane coordinate system is established on the local dentition plane, the width of the plane corresponding to the local dentition plane is taken as the X axis, the length of the plane corresponding to the local dentition plane is taken as the Y axis, and the protuberant angles of two adjacent teeth can be respectively calculated, as shown in fig. 4, the oblique white line is the axis projection line, the vertical white line is the parallel line of the Y axis of the dentition plane, and any one of the protuberant angles of the adjacent teeth is the included angle between the axis projection line and the Y axis of the dentition plane.

In one possible approach, determining a target protrusion angle of the target implant from protrusion angles of the adjacent teeth includes:

In the present embodiment, after the anterior process angles of the adjacent teeth of the implant are determined, for example, if the angle of the anterior process angle of one of the adjacent teeth of the implant is a and the angle of the anterior process angle of the adjacent tooth of the other implant is B, the value of the angle corresponding to (a + B)/2 is set as the target anterior process angle of the target implant. Therefore, the implant and the adjacent teeth have the same angle change trend, and the phenomenon of unattractive appearance caused by overlarge angle difference is avoided.

Step S103: and determining an in-point candidate line of the target implant on the oral CBCT image according to the variation of the pixel values on the initial implant planning line, and determining the position of the in-point of the target implant according to the variation of the pixel values on the in-point candidate line.

The calculation process of the entry point of the implant and the calculation process of the target anterior eminence angle of the implant are operated in parallel, an entry point candidate line on the oral cavity CBCT image is determined according to the variation of the pixel values on the initial implantation planning line, and the specific process comprises the following steps:

step S103-1: determining the pixel value of each pixel point on the initial planting planning line, and determining the pixel value difference between every two adjacent pixel points;

step S103-2: determining any one pixel point of two adjacent pixel points of the maximum value of the pixel value difference value absolute value as an in-point candidate point;

step S103-3: acquiring a CBCT local section image of the initial implantation gauge line from the oral CBCT image;

step S103-4: and mapping the in-point candidate point to the CBCT local section image to generate the in-point candidate line.

In steps S103-1 to S103-4, since the oral CBCT image of the patient can reflect the pixel value information of the pixel points, the specific pixel value of each pixel point on the initial implantation plan line can be determined, and then, the pixel value difference between all the adjacent pixel points on the initial implantation plan line is calculated. As an example, the pixel points a and B are adjacent pixel points, the specific pixel value corresponding to the pixel point a is a, the specific pixel value corresponding to the pixel point B is B, and with a predetermined window length, 2 pixel points traverse along the initial planting rule, and the variation of the pixel value in the window is determined, if the absolute value of the variation a-B of the pixel value between the pixel point a and the pixel point B is the maximum value of the difference between the adjacent pixel points, it is indicated that there is an obvious boundary between the pixel point a and the pixel point B, and thus it is indicated that there is a root of tooth growing between the pixel point a and the pixel point B. Therefore, by taking any one of the points a and b as an entry point candidate point, and taking the point a as the entry point candidate point as an example, the point a is mapped onto the dentition, and the entry point candidate line can be obtained. And on the candidate line of the entering point, the entering point of the implant is determined according to the variation of the pixel values on the candidate line of the entering point, comprising the following steps:

step S103-4-1: determining the pixel value of each pixel point on the in-point candidate line, and determining the pixel value difference between every two adjacent pixel points;

step S103-4-2: determining any one pixel point of two adjacent pixel points with the pixel value difference value being a positive maximum value as a first pixel point;

step S103-4-3: determining any one pixel point of two adjacent pixel points with the pixel value difference value being a negative maximum value as a second pixel point;

step S103-4-4: determining the midpoint position of a straight line formed by the first pixel point and the second pixel point, and determining the pixel point closest to the midpoint position as the in-point position of the target implant.

In step S103-4-1 to step S103-4-4, determining the variation of pixel values in a window by traversing a predetermined window length, for example, 2 pixels along the candidate line of the entry point, searching for a point with the maximum increase variation of pixel values and a point with the maximum decrease variation of pixel values, for example, the variation of pixel values between pixels c and d is the maximum increase value, that is, the pixel value between the pixel points c and d is the positive maximum value, one of the pixel points c and d is determined as the first pixel point, the variation of the pixel value between the pixel points e and f is the maximum value of decrease, namely, the pixel value between the pixel points e and f is a negative maximum value, one of the pixel points e and f is determined as a second pixel point, the midpoint of a straight line segment formed by the first pixel point and the second pixel point is determined, and the pixel point close to the midpoint is used as the in point of the implant. The maximum change of the pixel difference value of the first pixel point and the second pixel point shows that the boundary condition between the two points and the periphery is most obvious, so that the two points can be determined to be the corresponding positions of the original tooth root, the middle point is selected to be the entering point of the implant, and the accuracy and precision of drilling during implant implantation are guaranteed.

Step S104: and determining the tip position of the target implant according to the target anterior eminence angle and the entry point.

After the target anterior eminence angle of the implant and the entry point of the implant are determined, the tip position of the corresponding implant can be determined, the entry point is used as an original point, the target anterior eminence angle is used as a direction, a planning ray is made, the tail end of the planning ray is the tip position of the implant, the position of the tip position of the implant is determined according to the actual planning condition, and the specific determination process comprises the following steps:

step S104-1: if the implant is a lower dental implant, determining the distance between the entry point of the implant and the lower dental neural tube;

step S104-2: and if the distance between the point-in position of the target implant and the lower dental neural tube is smaller than a preset safety threshold, moving the tip position by a third preset distance along the direction close to the point-in position.

In steps S104-1 to S104-2, if the planning direction of the initial implantation planning line is from the head to the foot of the patient, this indicates that the planned implant is a lower dental implant, a neural tube exists on the lower tooth, and therefore, it is also necessary to detect the distance from the needle tip to the neural tube, the neural tube is generally marked manually by the doctor, and once the distance is smaller than the set value, the planned length is shortened, thereby ensuring the planning safety. Therefore, if the distance between the entry point of the implant and the neural tube of the lower tooth is smaller than the preset safety threshold, the length of the final implantation gauge line is shortened, the length of the implant is the length of the implantation gauge line meeting the requirement after shortening, if the neural tube is not marked, or the tip of the screw of the implant does not reach the neural tube, the planning length is determined by the length of the initial implantation gauge line on the two-dimensional image. The planned length, i.e. the tip position of the implant, is determined.

If the planned direction of the initial implantation gauge line is from the patient's foot to the head, this indicates that the planned implant is an upper dental implant, on which no neural tube is present. Therefore, the length of the implant is the length of the initial planting rule line.

Step S105: and determining an implant stress influence area in the oral CBCT image according to the in-point position and the tip position, and adjusting the in-point position and the tip position according to pixel values in the implant stress influence area.

And when the positions of the point of entry and the tip of the implant are determined, the pose of the implant is determined. Then, whether the requirements are met or not is judged according to the corresponding relation between the pixel values of the stress affected area of the implant and the bone density, a doctor is reminded, and the pose of the implant is finely adjusted.

In the embodiment, the initial implantation planning line on the two-dimensional dental arch curved surface image of the target object is acquired, the anterior process angle of the adjacent tooth of the target implant is determined according to the oral cavity CBCT image of the target object, and the target anterior process angle of the target implant is determined according to the anterior process angles of the adjacent tooth, so that a more appropriate anterior process angle is automatically found in the planning process, and the time for planning and adjusting by a doctor is saved. Determining an entry point candidate line on the oral cavity CBCT image according to the variation of the pixel values on an initial implantation planning line, determining the entry point position of the target implant according to the variation of the pixel values on the entry point candidate line, determining the tip position of the implant according to the target anterior-projection angle and the entry point position, determining an implant stress affected area in the oral cavity CBCT image according to the entry point position and the tip position, and adjusting the entry point position and the tip position according to the pixel values in the implant stress affected area. Searching adjacent teeth before and after the planned position, determining the external protrusion angle and the origin of the tooth root of the target implant, determining the initial implant position, analyzing whether the stress affected area of the implant meets the requirement of the supporting force, finely adjusting the initial implant position, and finally determining the final implant position of the implant. Therefore, the method helps a doctor to quickly and accurately plan the final planting position of the implant, reduces the work difficulty of the doctor, saves the planning time and improves the work efficiency.

In one possible embodiment, determining the implant force affected zone in the oral cavity CBCT image according to the location of the in-point and the tip comprises:

In this embodiment, a plane coordinate system is established by using the tip of the top of the implant corresponding to the contour line image as an origin and the axial direction as an X-axis, and straight line fitting is performed based on the pixel points on the contour line located in the first quadrant. By the straight line fitting method, a fitting line set consisting of a plurality of fitting line set can be obtained in the first quadrant of the contour line. And segmenting according to the coverage relation of the projections of the plurality of fitting line segments on the X axis in the coordinate system, namely according to the number of the projection points of the plurality of fitting line segments on the X axis. For example, taking the generated fitting line segments 1, 2, 3, and 4 as an example, for an arbitrary pixel point m, the abscissa value corresponding to the pixel point m in the coordinate system is a, the coordinate of the pixel point is (a, y 1) on the fitting line segment 1, the coordinate of the pixel point is (a, y 2) on the fitting line segment 2, the pixel point with the coordinate of (a, y 3) does not exist on the fitting line segment 3, the pixel point with the coordinate of (a, y 4) does not exist on the fitting line segment 4, that is, the pixel point m corresponds to the pixel point, and the fitting line segments satisfying the coverage relationship with the point are the fitting line segment 1 and the fitting line segment 2, that is, the number 2 of the fitting line segments satisfying the coverage relationship with the point is two. For any adjacent pixel point N and M, the abscissa value of N is a-1, the abscissa value of M is a, the number of fitting line segments meeting the coverage relation with the pixel point N is N, and the number of fitting line segments meeting the coverage relation with the pixel point M is M. If N is equal to M, the pixel point N and M belong to the same implant segmentation area; and if N is not equal to M, the pixel points N and M do not belong to the same implant segmentation region. The length characteristic of each implant segmentation region can be determined according to the abscissa value of the starting point and the ending point of each implant segmentation region, the diameter characteristic of each implant segmentation region can be determined according to the ordinate of each pixel point, and the thread type characteristic of each implant segmentation region is determined according to the number of the fitted line segments in each implant segmentation region. For any segment region of the implant, the abscissa value of the starting point is A, the abscissa value of the final point is B, and the length of the segment region is the absolute value of A-B; for any pixel point of the segment region, if the coordinate value corresponding to the point is R, the diameter of the segment region corresponding to the point is 2R; for any segment area of the implant, if the number of the fitting line segments covered by the segment is one, determining that the thread type corresponding to the segment of the implant is a triangular thread or a non-thread; if the number of the fitting line segments covered by the implant segment is two, determining that the thread type corresponding to the implant segment is a common trapezoidal thread, and determining the starting point and the stopping point of the segment as the starting point and the stopping point of the common trapezoidal thread; and if the number of the fitting line segments covered by the implant segment is three, determining that the thread type corresponding to the implant segment is the staggered trapezoidal thread, and determining the starting point and the ending point of the segment as the starting point and the ending point of the staggered trapezoidal thread. Based on the above, the parameters of the stress-affected area, such as the length of each implant segment area containing the segment area, the thread type of the segment area, the diameters of the two ends of the segment area, and the like, can be determined. The stress-affected area parameter may also include other parameters, which are determined according to the fineness of the generated implant model, such as a thread pitch parameter, a material parameter, and the like, but the present invention is not limited thereto.

In one possible embodiment, the method further comprises:

In this embodiment, after the implant is placed, a region with a large pressure on the bone, i.e., a stress-affected region, of the peripheral screw thread of the implant can be calculated by using information such as the screw thread of the implant, as shown in fig. 6, the region is a frustum image wrapped around the implant, the frustum image is cut into multiple parts along the circumference, the area of each part is the same, and the stress-affected sub-region divided by each stress-affected region includes a plurality of pixel points.

In a possible implementation manner, the evaluating the supporting capability of each stress-affected sub-region according to the pixel value of each pixel point in each stress-affected sub-region includes:

In this embodiment, after the pixel value of each pixel point is determined, the bone density value corresponding to each pixel point can be determined according to the corresponding relationship between the pixel value and the bone density value, for example, if the pixel value of a certain pixel point is 600, the bone density value corresponding to the pixel point is determined to be 600 according to the corresponding relationship between the pixel value and the bone density value, and the preset bone density value threshold is 800, so that the point is not taken as the first pixel point, if the total number of the pixel points of any stress-affected sub-area is 1000, the number of the first pixel points of the stress-affected sub-area is 500, and the number of the first pixel points is 400, it is indicated that the supporting capability of the stress-affected sub-area meets the requirement, and it is indicated that the supporting capability of the current planting position of the implant meets the requirement only if the supporting capabilities of all the stress-affected sub-areas meet the requirement, it does not need to be adjusted and moved by the doctor.

In a possible embodiment, the adjusting the position of the in-point and the position of the tip according to the support capability evaluation result includes:

and if the implant supporting capacity of the sub-image in the stress affected area still does not meet the requirement, moving the point-in position and the point-out position by a second preset distance along the opposite direction of the normal direction (the direction shown by the arrow in fig. 6) of the sub-area in the stress affected area.

In this embodiment, if the total number of the pixel points of any stress-affected sub-area is 1000, the number of the first pixel points of the stress-affected sub-area is 300, and the preset threshold of the number of the first pixel points is 400, it indicates that the support capability of the stress-affected sub-area does not meet the requirement, that is, the support capability of the current planting position of the implant does not meet the requirement, and a doctor needs to adjust and move the implant. The upper computer prompts a doctor to carry out automatic optimization, moves the implant by 0.5mm along the direction opposite to the normal direction of the stressed sub-area, judges the supporting capacity again, moves the implant by 1mm along the direction opposite to the normal direction of the stressed sub-area if the supporting capacity still does not meet the requirement, judges the supporting capacity again, prompts a user and abandons the two movements if the two movements do not solve the problem of insufficient supporting capacity, and moves the position of the implant back to the original position.

An embodiment of the present invention further provides an implant aided planning apparatus, and referring to fig. 7, a functional module diagram of the implant aided planning apparatus of the present invention is shown, and the apparatus may include the following modules:

an obtaining unit 701, configured to obtain an initial implantation gauge line on a two-dimensional dental arch curved surface image of a target object, where the two-dimensional dental arch curved surface image is obtained by performing curved surface reconstruction based on a CBCT image of an oral cavity of the target object;

a first determining unit 702, configured to determine a protrusion angle of adjacent teeth of a target implant in an oral CBCT image of the target object according to the initial implantation gauge line, and determine a target protrusion angle of the target implant according to the protrusion angle of the adjacent teeth;

a second determining unit 703, configured to determine an entry point candidate line of the target implant on the oral CBCT image according to a variation of a pixel value on the initial implantation planning line, and determine an entry point position of the target implant according to a variation of a pixel value on the entry point candidate line;

a third determining unit 704, configured to determine a tip position of the target implant according to the target anterior horn and the entry point;

an adjusting unit 705, configured to determine an implant stressed area in the oral CBCT image according to the in-point position and the tip position, and adjust the in-point position and the tip position according to a pixel value in the implant stressed area.

In a possible implementation, the adjusting unit 705 includes:

In one possible embodiment, the evaluation module comprises:

In one possible embodiment, the first adjusting module includes:

In one possible implementation, the first determining unit 702 includes:

In a possible implementation, the second determining unit 703 includes:

In a possible implementation, the adjusting unit 705 includes: the first judgment module is used for determining the distance between the position of an entry point of the target implant and a lower dental neural tube if the target implant is a lower dental implant;

Based on the same inventive concept, another embodiment of the present invention provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor implements the steps of the implant aided planning method according to any of the above embodiments of the present invention when executed. The embodiments in the present specification are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

In yet another embodiment of the present invention, there is also provided a computer-readable storage medium having stored therein instructions, which when run on a computer, cause the computer to perform the implant assisted planning method according to any one of the above embodiments.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, apparatus, or computer program product. Accordingly, embodiments of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, embodiments of the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

Embodiments of the present invention are described with reference to flowchart illustrations and/or block diagrams of methods, terminal devices (apparatus), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing terminal to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing terminal to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing terminal to cause a series of operational steps to be performed on the computer or other programmable terminal to produce a computer implemented process such that the instructions which execute on the computer or other programmable terminal provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. "and/or" means that either or both of them can be selected. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or terminal that comprises the element.

The method, the device, the electronic device and the storage medium for aided implant planning provided by the invention are described in detail, and a specific example is applied in the text to explain the principle and the implementation of the invention, and the description of the embodiment is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims

1. A dental implant aided planning method, the method comprising:

2. The method of claim 1, wherein determining an implant force affected zone in the oral CBCT image from the location of the in-point and the location of the tip comprises:

3. The method of claim 2, wherein said adjusting the in-point location and the tip location by pixel values within the implant force affected zone comprises:

4. The method of claim 3, wherein evaluating the support capacity of each force-affected sub-region based on pixel values of pixels in each force-affected sub-region comprises:

5. The method of claim 4, wherein adjusting the in-point location and the tip location according to the support capability assessment comprises:

and if the implant supporting capacity of the sub-image in the stress affected area still does not meet the requirement, moving the point-in position and the tip position by a second preset distance along the opposite direction of the normal direction of the sub-area in the stress affected area.

6. The method of claim 1, wherein determining a protrusion angle of adjacent teeth of a target implant in the oral CBCT image of the target subject from the initial implant prescription line comprises:

7. The method of claim 1, wherein determining a target protrusion angle for the target implant from protrusion angles of the adjacent teeth comprises:

8. The method as claimed in claim 1, wherein determining an in-point candidate line on the oral cavity CBCT image according to a variation amount of pixel values on the initial planting plan line comprises:

9. The method of claim 1, wherein determining the location of the entry point of the target implant according to a variation of the pixel values on the entry point candidate line comprises:

10. The method of claim 1, further comprising:

11. A dental implant aided planning apparatus, the apparatus comprising:

12. The apparatus of claim 11, wherein the adjusting unit comprises:

13. The apparatus of claim 12, wherein the adjusting unit comprises:

14. The apparatus of claim 13, wherein the evaluation module comprises:

15. The apparatus of claim 14, wherein the first adjusting module comprises:

and the second adjusting submodule is used for moving the position of the point-in point and the position of the tip by a second preset distance along the opposite direction of the normal direction of the sub-area of the stress affected area if the supporting capacity of the implant of the sub-image of the stress affected area still does not meet the requirement.

16. The apparatus according to claim 11, wherein the first determining unit comprises:

17. The apparatus according to claim 11, wherein the second determining unit comprises:

18. The apparatus according to claim 11, wherein the second determining unit comprises:

19. The apparatus of claim 11, wherein the adjusting unit comprises: the first judgment module is used for determining the distance between the position of an entry point of the target implant and a lower dental neural tube if the target implant is a lower dental implant;

20. An electronic device is characterized by comprising a processor, a communication interface, a memory and a communication bus, wherein the processor and the communication interface are used for realizing mutual communication by the memory through the communication bus;

a memory for storing a computer program;

a processor for implementing the method steps of any of claims 1-10 when executing a program stored in the memory.

21. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the method according to any one of claims 1-10.