KR102498679B1 - Device for generating tooth preparation tool path - Google Patents

Abstract

The present invention is an apparatus for generating a movement path of a preparation tool that automatically prepares the teeth of a person to be treated, comprising: a data acquisition unit that acquires a 3D tooth image of a person to be treated and preparation data of the 3D tooth image; A junction surface creation unit that creates a junction surface where the preparation area remaining after deletion and the preparation area to be deleted using the preparation tool in the 3D tooth image are in contact, and an offset plane that creates an offset surface by offsetting the junction surface by the radius of the preparation tool An apparatus for generating a movement path of a tooth preparation tool including a unit and a path generation unit for generating a movement path of the preparation tool based on an offset plane is provided.

Description

Movement path generation device of tooth preparation tool {DEVICE FOR GENERATING TOOTH PREPARATION TOOL PATH}

The present invention relates to an apparatus for generating a movement path of a tooth preparation tool, and more particularly, to an apparatus for generating a movement path of a tooth preparation tool capable of preventing interference between a tooth preparation tool and a processing surface of a tooth.

In general, prosthetics means restoring the function of a tooth by reinforcing a partial defect of a tooth or a defect of the tooth itself, and a fixed type such as a crown, a bridge, and a resin; They are classified as removable like dentures.

Here, the crown means to cover the tooth with gold or ceramic, the bridge means to connect the artificial tooth in the middle using the adjacent tooth of the extracted tooth as a bridge, and the resin, amalgam, etc. means that

At this time, in the case of prosthetics such as crowns and bridges, a series of preparation processes for removing portions of enamel and dentin of teeth are called tooth preparations to prevent interference between natural teeth and prostheses.

Then, when the tooth prep is completed, a temporary crown for protecting the tooth is manufactured and coupled to the tooth through processes such as impression and bite taking.

In addition, the tooth model acquired through impression and occlusion acquisition is delivered to a specialized laboratory to manufacture a prosthetic appliance. When the prosthetic appliance is manufactured, the temporary crown is removed and finally combined with the tooth.

At this time, in order for the prosthesis to be tightly coupled to the removed part of the target tooth without interference with the surrounding teeth and to be stably supported without damaging the tooth, a shape that can be stably combined with the prosthesis while minimizing the amount of tooth removal during tooth preparation is designed. It is important to do

However, in the prior art, since the shape and state of tooth extraction are influenced by the operator's experience or proficiency, there have been problems such as the prosthesis falling out of the tooth after coupling or the tooth being damaged by masticatory pressure applied to the prosthesis.

Furthermore, since the prosthesis is manufactured after tooth preparation, there is a problem in that the subject has to endure aesthetic and functional discomfort due to the temporary crown used for several days to weeks while the prosthesis is manufactured.

In order to solve such a problem, dentistry is currently developing materials for medical automation and automating treatment actions at the same time. In order to automate this field of dentistry, a 3D dental scanner and CBCT are used to acquire the shape of a tooth, and then an automatic preparation procedure is attempted to precisely remove abnormal parts such as cavities with a medical robot.

In particular, the task of removing an abnormal part of a tooth using a robot is performed by planning a movement path of a preparation tool at the end of the robot. These moving paths must be precisely created through complex processes such as the shape of teeth and the force applied by the robot.

In order to solve the problems of the prior art as described above, the present invention has the advantage that the creation time of the movement path is short because the algorithm is simple and concise, and the interference between the preparation tool and the processing surface of the tooth can be checked in advance. It is an object of the present invention to provide a device for generating a movement path of a tooth preparation tool.

In addition, an object of the present invention is to provide an apparatus for generating a movement path of a tooth preparation tool that can automatically perform tooth preparation with high accuracy regardless of the operator's skill level.

The technical problems to be achieved in the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned can be clearly understood by those skilled in the art from the description below. There will be.

In order to solve the above problems, the present invention is a device for generating a movement path of a preparation tool that automatically prepares the teeth of a person to be treated, and data for acquiring a 3D tooth image of a person to be treated and preparation data of the 3D tooth image. The acquisition unit and the joint surface generation unit that creates the joint surface where the preparation area remaining after deletion and the preparation area to be deleted using the preparation tool in the 3D tooth image are in contact with each other on the basis of the preparation data, and the joint surface is offset by the radius of the preparation tool Provided is an apparatus for generating a movement path of a tooth preparation tool, including an offset surface generating unit generating an offset surface by using the offset surface, and a path generating unit generating a movement path of the preparation tool based on the offset surface.

Here, the offset surface generation unit may create an offset surface by performing an offset process on a plurality of vertices constituting the bonding surface.

In addition, the offset plane generation unit may calculate an offset vector by summing normal vectors of planes connected to vertices in consideration of weights, and may generate offset vertices by adding the offset vectors to the vertices.

Also, the offset plane generation unit may generate an offset vertex by multiplying the offset vector by the radius of the preparation tool and adding the offset vector to the vertex.

In addition, the bonding surface generation unit may generate bonding lines for each of a plurality of slices based on a plurality of projection points obtained by projecting a plurality of vertices on a plurality of slices passing through the 3D tooth image.

In addition, the joint surface generation unit may connect a plurality of projected points to form a connection line, and may generate a joint line by connecting intersection points where surfaces connected to the connection lines and vertices intersect.

Also, the joint surface generation unit may generate a joint surface by stacking a plurality of joint lines for each slice.

In addition, the offset plane generating unit may generate an offset line for each of a plurality of slices based on a plurality of projection points in which a plurality of vertices constituting the offset plane are projected on a plurality of slices passing through the 3D tooth image.

In addition, the offset plane generation unit may connect a plurality of projected points to form a connection line, and may generate an offset line by connecting an intersection point where a plane connected to a vertex intersects the connection line with the connection line.

Also, the offset plane generating unit may generate an offset plane by stacking a plurality of offset lines for each slice.

Also, the path generator may set an inclination angle of the preparation tool based on the angle of the normal vector of the offset plane.

According to the present invention, since the movement path of the tooth preparation tool is created while comparing the joint line and the offset line in the tooth image, the algorithm is simple and concise, so the generation time of the movement path is short, and the side of the preparation tool and the tooth There is an advantage of checking the interference of the machined surface of the machine in advance.

In addition, according to the present invention, since the tooth preparation is performed using the automatically generated movement path of the preparation tool, highly accurate tooth preparation can be performed regardless of the operator's skill level.

The effects obtainable in the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description below. will be.

1 is a schematic block diagram of an apparatus for generating a movement path of a tooth preparation tool according to an embodiment of the present invention.
FIG. 2 is a specific block diagram of a control unit of FIG. 1 .
FIG. 3 is a diagram illustrating preparation types classified according to the location and shape of a deletion region to be deleted in a tooth image.
4 is a side cross-sectional view of a tooth image according to the type of preparation of FIG. 3 .
5 is a view for explaining a method of setting an inclination angle of a preparation tool according to an embodiment of the present invention.
6 is a diagram showing an original 3D tooth image (a), an obscepted 3D tooth image (b), and an image (c) in which these images are superimposed in a STereoLithography (STL) format.
7 is a diagram for explaining a method of generating a junction curve by a slicing technique.
8 is a diagram illustrating a movement path of a tooth preparation tool according to an embodiment of the present invention.

The above objects and means of the present invention and the effects thereof will become clearer through the following detailed description in relation to the accompanying drawings, and accordingly, those skilled in the art to which the present invention belongs will easily understand the technical idea of the present invention. will be able to carry out In addition, in describing the present invention, if it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

In this specification, terms such as “or” and “at least one” may represent one of the words listed together, or a combination of two or more. For example, "or B" and "at least one of B" may include only one of A or B, or may include both A and B.

In this specification, terms such as 'first' and 'second' may be used to describe various elements, but the elements should not be limited by the above terms. In addition, the above terms should not be interpreted as limiting the order of each component, and may be used for the purpose of distinguishing one component from another. For example, a 'first element' may be named a 'second element', and similarly, a 'second element' may also be named a 'first element'.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic block diagram of an apparatus for generating a movement path of a tooth preparation tool according to an embodiment of the present invention, and FIG. 2 is a specific block diagram of a control unit of FIG. 1 .

The apparatus 100 for generating a movement path of a tooth preparation tool according to an embodiment of the present invention is an electronic device that can be executed by a computer program, and is a component of a preparation tool that automatically prepares the teeth of a person to be treated. It is a device that creates a movement path. Here, the preparation refers to a preparation process for deleting a carious tooth region and manufacturing a prosthesis.

The preparation tool is a device that automatically removes and processes teeth of a person to be treated in a shape suitable for combination with a prosthesis based on a preparation image.

The tooth image is a 3D image in a STereoLithography (STL) format and may be an oral scan image, a CT image, or a matching image in which an oral scan image and a CT image are matched.

Here, the oral scan image may provide information on the shape of the crown of the tooth exposed to the outside and the shape of the gum around the tooth. At this time, the oral scan image is obtained by directly scanning the inside of the oral cavity of the recipient through an oral scanner or the like, or by scanning an impression model that imitates the inside of the recipient's oral cavity in an intaglio or a plaster model created through embossing of the impression model. The scan image of the impression model may be inverted and used as an oral scan image.

In addition, CT images can provide information on the shape of not only the crown, but also the root, alveolar bone, and bone density of the crown, root, and alveolar bone. In this case, the CT image may be acquired by CT scanning the inside of the oral cavity of the person to be treated.

Referring to FIG. 1 , an apparatus 100 for generating a movement path of a tooth preparation tool according to an embodiment of the present invention includes a communication unit 110, an input unit 120, a display unit 130, a storage unit 140, and a control unit 150. ) may be included.

The communication unit 110 is a component that performs communication with external devices such as an image capture device (not shown) and a server (not shown), and can receive image data. For example, the communication unit 110 may perform ^5th generation communication (5G), long term evolution-advanced (LTE-A), long term evolution (LTE), Bluetooth, bluetooth low energy (BLE), and near field communication (NFC). It is possible to perform wireless communication such as, etc., and wired communication such as cable communication.

In this case, the image data may include other image data measured by other measurement methods in addition to oral scan image data. For example, other image data may include CT image data, MRI image data, and the like.

The input unit 120 generates input data in response to a user's input, and may include at least one input means. For example, the input unit 120 includes a keyboard, a key pad, a dome switch, a touch panel, a touch key, a mouse, and a menu button ( menu button), etc.

The display unit 130 displays display data according to the operation of the device 100 for generating a movement path of the tooth preparation tool. Such display data may include image data. For example, the display unit 130 may include a liquid crystal display (LCD), a light emitting diode (LED) display, an organic LED (OLED) display, and a micro electromechanical system (MEMS). mechanical systems displays and electronic paper displays. In addition, the display unit 130 may be combined with the input unit 120 and implemented as a touch screen or the like.

The storage unit 140 stores various information and programs necessary for the operation of the movement path generating device 100 of the tooth preparation tool. For example, the storage unit 140 may store image data received from an image capture device, etc., and an algorithm related to a method for generating a movement path of a tooth preparation tool according to an embodiment of the present invention, which will be described later.

The control unit 150 performs an operation of generating a movement path of the tooth preparation tool with respect to tooth image data received from an image capture device or server or pre-stored in the storage unit 140 . To this end, the controller 150 may receive tooth image data from an image acquisition device or a server and store it in the storage unit 140 . Also, the control unit 150 may control operations of the communication unit 110 , the input unit 120 , the display unit 130 and the storage unit 140 .

Referring to FIG. 2 , the control unit 150 may include a data acquisition unit 151, a junction surface generation unit 152, an offset surface generation unit 153, and a path generation unit 154.

The data acquisition unit 151 may acquire a tooth image of a person to be treated and preparation data of the tooth image. Here, the data acquisition unit 151 may receive a tooth image from an image acquisition device or a server or may use a tooth image pre-stored in the storage unit 140 .

The joint surface generation unit 152 may extract a region to be deleted from the tooth image based on the preparation data, and may create a joint surface where the region to be deleted and the remaining preparation region after the deletion are in contact with each other using a preparation tool in the tooth image.

FIG. 3 is a diagram illustrating preparation types classified according to the location and shape of a deletion region to be deleted from a tooth image, and FIG. 4 is a side cross-sectional view of a tooth image according to the preparation type of FIG. 3 .

Referring to FIGS. 3 and 4 , preparations may be classified into inlays (a), onlays (b), and crownlays (c).

Inlay (a) is a treatment method for restoring a relatively narrow area, and is a treatment method when tooth decay penetrates deep into the tooth and is narrow and deep. And, the onlay (b) is a treatment method for restoring a relatively wide area, and is a method for treating caries that occurs over a wide range. In addition, the crown lay (c) is a treatment method in which a crown is placed after removing the entire crown when filling the entire crown occurs.

Referring to FIG. 4 , a tooth image 10 to which an inlay (a), an onlay (b), and a crown lay (c) are applied, respectively, includes a deleted area 3 to be deleted from the tooth image 10 and a remaining area after deletion. It includes a prep area (4).

Here, the joint surface generation unit 152 may extract the deleted region 3 based on the preparation data, and the joint surface 2 and the deleted region 3 where the deleted region 3 and the preparation region 4 contact each other. ) can be divided into an access surface (3) through which the preparation tool can access the tooth, and through this, the joint surface (2) can be created in the tooth image (10).

5 is a view for explaining a method of setting an inclination angle of a preparation tool according to an embodiment of the present invention.

In FIG. 5 , the joint surface 2 is a surface on which the preparation tool 10 contacts teeth during preparation of the preparation area 3, and the offset surface 5 is the preparation tool during preparation of the preparation area 3 ( 10) is a plane formed by the center shift. Here, the distance between the bonding surface 2 and the offset surface 5 may correspond to the radius of the end of the preparation tool 10 .

Referring to FIG. 5 (a), in the conventional preparation method, the preparation tool 10 is placed vertically and the tooth is removed while contacting the joint surface 2 of the tooth. Here, when the preparation tool 10 performs preparation processing at a position where the slope of the normal vector of the offset surface 5 becomes less than a certain angle (eg, 10 degrees), the side surface of the preparation tool 10 and the joint surface 2 This interference causes a problem that the preparation tool 10 deletes to the inside of the bonding surface 2.

Referring to FIG. 5 (b) , in the apparatus for generating a movement path of a tooth preparation tool according to an embodiment of the present invention, the path generator 154 moves the preparation tool 10 based on the angle of the normal vector of the offset surface 5 ) may be set, and the preparation tool 10 may be tilted at the set angle at a position where interference occurs between the side surface of the preparation tool 10 and the bonding surface 2 .

That is, when the preparation tool 10 is located at a position where the angle of the normal vector of the offset surface 5 is less than or equal to the set angle, the central axis of the preparation tool 10 is tilted outward, so that the side and side of the preparation tool 10 Since the joint surface 2 prevents interference, it is possible to prevent the preparation tool 10 from cutting to the inside of the joint surface 2 .

The offset surface generation unit 153 may generate the offset surface 5 by performing offset processing on the bonding surface 2 by the radius of the preparation tool 10 .

In general, the offset method of a 3D tooth image in the form of STL (STereoLithography) performs offset by moving the face of the STL, but this method requires removing interference between the offset faces or filling in between the offset faces. . However, there is a problem that such a task is very complicated.

However, the offset surface generation unit 153 according to the embodiment of the present invention does not offset the plane of the STL, but offsets a plurality of vertices constituting the joint surface 2 to form the offset surface 5 By generating , offset can be performed relatively simply and quickly.

Here, the offset vector may be calculated as an arithmetic average of normal vectors of all faces connected to the vertex, but may become inaccurate when the angle between the normal vectors of adjacent faces is relatively large.

In order to solve this problem, the offset plane generating unit 153 according to an embodiment of the present invention, as shown in Equation 1 below, considers the weight (W _j ) and calculates the normal vector (N) of all planes connected to the vertex. The offset vector (V _offset ) may be calculated by summing _{i and j} .

<Equation 1>

where N _i,j is the normal vector of the face connected to vertex i.

As shown in Equation 2 below, the offset plane generator 153 multiplies the offset vector (V _offset ) by the radius (d _offset ) of the preparation tool 10 and adds it to the original vertex (P _i,original ) to obtain an offset A vertex (P _i,new ) can be created.

<Equation 2>

Here, P _i,original is the original vertex i, and P _i,new is the offset i vertex.

In addition, the radius d _offset of the preparation tool 10 varies depending on the type of preparation tool 10 and may be a value preset by a user.

The weight (W _n ) may be calculated by Equation 3 below.

<Equation 3>

Here, n is a natural number greater than or equal to 2 and corresponds to the number of faces connected to i vertices.

6 is a diagram showing an original 3D tooth image (a), an obscepted 3D tooth image (b), and an image (c) in which these images are superimposed in a STereoLithography (STL) format.

As shown in FIG. 6, the offset 3D tooth image (b) can be used to generate the movement path of the preparation tool 10 by offsetting the original 3D tooth image (a) using the above offset method. .

The path generator 154 may generate a movement path of the preparation tool 10 based on the offset surface 5 .

7 is a diagram for explaining a method of generating a junction curve by a slicing technique.

Referring to FIG. 7 , the bonding surface generating unit 152 has a plurality of projection points at which a plurality of vertices 1, 2, and 3 are projected on a plurality of slice planes passing through a 3D tooth image. The junction line 2a may be generated for each of a plurality of slice planes based on (1', 2', 3').

Specifically, the bonding surface generating unit 152 connects a plurality of projected points 1', 2', and 3' to form connection lines 1'-2', 2'-3', and 1'-3' , and connect the intersection points (P ₃₁ , P ₁₂ ) where the planes connected to the connection lines (1'-2', 2'-3', 1'-3') and the vertices (1, 2, 3) intersect. Thus, the bonding line 2a (P ₃₁ -P ₁₂ ) can be created.

Also, the bonding surface generating unit 152 may generate the bonding surface 2 by stacking the bonding lines 2a for each slice plane.

Similarly, the offset plane generating unit 153 may also generate the offset line and the offset plane 5 using a slicing technique.

Specifically, the offset plane generating unit 153 generates an offset line for each of a plurality of slices based on a plurality of projection points in which a plurality of vertices constituting the offset plane 5 are projected on a plurality of slices passing through the 3D tooth image. can create

In addition, the offset plane generating unit 153 may connect a plurality of projected points to form a connection line, and may generate an offset line by connecting an intersection point where the connection line and the plane connected to the vertex intersect.

Also, the offset plane generating unit 153 may generate an offset plane by stacking a plurality of offset lines for each slice.

8 is a diagram illustrating a movement path of a tooth preparation tool according to an embodiment of the present invention.

Referring to FIG. 8 , the apparatus for generating a movement path of the tooth preparation tool according to the present invention may generate a movement path of the tooth preparation tool 10 using a joint line and an offset line generated by a slicing technique.

Here, the position and posture of the preparation tool 10 change every time according to the normal vector of the joining line and the offset line, but it can be confirmed that there is no interference while comparing and checking the joining line and the offset line.

The movement path of the tooth preparation tool 10 may be created in a zigzag or offset manner to remove the inside of the area of the preparation area. And, the movement path of the tooth preparation tool 10 can be implemented to be robot programming.

In this way, since the moving path generating device of the tooth preparation tool according to the embodiment of the present invention generates the moving path of the tooth preparation tool 10 while comparing the joining line and the offset line, the moving path is simple and concise in the algorithm. There is an advantage in that the generation time of is short, and there is an advantage in checking interference between the side surface of the preparation tool 10 and the bonding surface 2 in advance.

In addition, according to the present invention, since the tooth preparation is performed using the automatically generated movement path of the preparation tool 10, highly accurate tooth preparation can be performed regardless of the operator's skill level.

In the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention is not limited to the described embodiments, and should be defined by the following claims and equivalents thereof.

110: communication unit 120: input unit
130: display unit 140: storage unit
150: control unit 151: data acquisition unit
152: junction surface generation unit 153: offset surface generation unit
154: path generation unit

Claims (11)

A device for generating a movement path of a preparation tool that automatically prepares a person's teeth,
a data acquisition unit acquiring a 3D tooth image of the person to be treated and preparation data of the 3D tooth image;
an abutment surface generating unit that generates a junction surface where a region to be deleted and a preparation region remaining after deletion are in contact with each other on the basis of the preparation data using the preparation tool in the 3D tooth image;
an offset surface generator generating an offset surface by offsetting the bonding surface by a radius of the preparation tool; and
A path generator for generating a movement path of the preparation tool based on the offset plane;
The offset plane generating unit
Generating the offset surface by offsetting a plurality of vertices constituting the joint surface
A device for generating a moving path of a tooth preparation tool.
delete According to claim 1,
The offset plane generating unit
Calculating an offset vector by summing normal vectors of faces connected to the vertex in consideration of the weight, and generating an offset vertex by adding the offset vector to the vertex
A device for generating a movement path of a tooth preparation tool.
According to claim 3,
The offset plane generating unit
Generating the offset vertex by multiplying the offset vector by the radius of the prep tool and adding it to the vertex.
A device for generating a movement path of a tooth preparation tool.
According to claim 1,
The bonding surface generating unit
Generating a joint line for each of the plurality of slices based on a plurality of projection points in which the plurality of vertices are projected on a plurality of slices passing through the 3-dimensional tooth image
A device for generating a movement path of a tooth preparation tool.
According to claim 5,
The bonding surface generating unit
Connecting the plurality of projection points to form a connection line, and connecting the intersection point where the connection line and the plane connected to the vertex intersect to create a junction line
A device for generating a movement path of a tooth preparation tool.
According to claim 6,
The bonding surface generating unit
Creating the bonding surface by stacking the bonding lines for each of the plurality of slices
A device for generating a movement path of a tooth preparation tool.
According to claim 1,
The offset plane generating unit
Generating an offset line for each of the plurality of slices based on a plurality of projection points in which a plurality of vertices constituting the offset plane are projected on a plurality of slices passing through the 3-dimensional tooth image
A device for generating a movement path of a tooth preparation tool.
According to claim 8,
The offset plane generating unit
Connecting the plurality of projection points to form a connection line, and generating an offset line by connecting an intersection where the connection line and a plane connected to the vertex intersect.
A device for generating a movement path of a tooth preparation tool.
According to claim 9,
The offset plane generating unit
Generating the offset plane by stacking the offset lines for each of the plurality of slices
A device for generating a movement path of a tooth preparation tool.
According to claim 9,
The route generator
Setting the inclination angle of the preparation tool based on the angle of the normal vector of the offset surface
A device for generating a movement path of a tooth preparation tool.

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