EA043155B1 - METHOD AND SYSTEM FOR ALIGNING TEETH ON THE BASIS OF MODELING THE MOVEMENT OF CROWN AND ROOTS - Google Patents

Description

The invention relates to dentistry, in particular orthodontics. This invention includes modeling the movement of teeth, the creation of stages of movement of the teeth and the production of 3D-printed caps to align the bite.

State of the art

Not all people understand how important it is to have the right bite. Very few people decide to go to the orthodontist, especially if there are no external signs of malocclusion.

However, according to statistics, about 80% of people have a malocclusion.

There are many reasons for correcting the bite: the risk of developing gum disease and caries is reduced, teeth will not wear out, well-chewed food will not cause diseases of the digestive system, facial features will become symmetrical, diction will be clear.

There are different ways to align teeth: braces; aligners, or caps; in especially severe cases, jaw surgery is required.

Known utility model RU 132340 U1, Orthodontic apparatus, Persin Leonid Semyonovich and others (RU), published 20.09.2013. This utility model describes an orthodontic appliance that includes a bracket system with a wire arch and a labial bumper, while the labial bumper is mounted on the bracket system arc by means of hook-shaped elements made at both ends of the bracket, which are placed between the 3rd and 4th teeth or between the 4th and 5th teeth, counting from the middle of the dentition.

Known invention RU 2559762 C1, Method for transversal expansion of the upper dentition, Yulia Sergeevna Lipova et al. (RU), published on 10.08.2015. This invention describes a method for transversal expansion of the upper dentition, including the expansion of the dentition along the transversal using a fixed apparatus with a screw on the upper jaw, while simultaneously with the expansion of the dentition along the transversal, brackets are fixed on teeth 1.5, 1.3, 1.2, 1.1, 2.1 , 2.2, 2.3, 2.5, as the teeth of the upper jaw are aligned, the bracket system is glued to the lower jaw, after 2-3 months the fixed apparatus is removed from the upper jaw, brackets are fixed on teeth 1.4, 2.4, rings with buccal tubes on the molars and further treatment is carried out according to a known method in a standard way using a bracket system.

Known invention RU 2495642 C2, Method for manufacturing an individual orthodontic appliance and apparatus made by this method, X 32 (FR), published 10/20/2013. This invention describes a method for manufacturing an individual orthodontic appliance, containing at least one therapeutic orthodontic arch and a plurality of elements, each of which contains a bracket with at least one groove configured to receive the specified orthodontic arch, each bracket is made with the possibility of installation on an intermediate part, which, in turn, is made with the possibility of installation on a base intended for installation on the front or back side of the tooth, while this method includes individual computer design of these brackets, intermediate parts and bases after imaging in the corrected position of the dental arch and of the sides of the teeth on which it is necessary to fix the indicated bases, on the indicated image the design arch is positioned relative to the indicated sides of the teeth, while the geometry of the design arch is similar to the geometry of the medical orthodontic arch, and then computer modeling of these elements is performed so that their envelope corresponds to the geometry of the gap, which according to the end of orthodontic treatment will separate the tooth and the arch when the tooth is in its corrected position and the treatment arch is back to its original shape.

Known invention US 7585172 B2, Orthodontic treatment planning with user-specified simulation of tooth movement, ORAMETRIX INC (US), published 09/08/2009. The present invention describes a device for adjusting the orthodontic treatment of a patient who already has braces attached to the teeth, and in which the braces are enclosed in braces, a scanning system for scanning the patient's dentition, including the braces themselves; a workstation having a processor, memory and display; as well as software for processing captured images from said scanning system and converting said captured images into a current virtual three-dimensional model of teeth with brackets located on the surface of the patient's teeth; and said software further allows the user to quantify and accurately quantify the amount of movement of said patient's teeth, thereby allowing orthodontic treatment to be adjusted for said orthodontic patient already undergoing orthodontic treatment.

Known invention WO 2011/103876 A1, DYNAMIC VIRTUAL ARTICULATOR, 3SHAPE AS (DK), published 09/01/2011. The present invention describes a method of using a dynamic virtual articulator to simulate occlusion when performing computer-aided design of one or more dental prostheses for a patient, implemented using a computer, including the following steps: providing a virtual articulator containing a virtual 3D model of the upper jaw and a virtual 3D model of the lower jaw , repeating the upper jaw and lower jaw of the patient, respectively; ensuring the movement of the virtual upper jaw and the virtual lower jaw relative to each other

- 1 043155 for simulating dynamic occlusion in the event of contacts between the teeth of the virtual upper and virtual lower jaws, and the method includes preventing the virtual surface of the teeth of the virtual upper jaw and the virtual surface of the teeth of the virtual lower jaw from intersecting with said contacts, while these prostheses are permeable .

When using these inventions, full automation of the treatment plan and the production of caps for alignment of teeth is not ensured, since the alignment process is extremely complex. At the same time, manual planning of each stage of treatment is quite difficult and time-consuming, and requires extensive training of physicians.

In addition, braces cause pain, they have to clean out food debris well, they scratch the enamel, lead to repeated caries and unpredictable results in the correction of tooth growth.

The essence of the technical solution

This technical solution is aimed at eliminating the disadvantages inherent in existing inventions.

EFFECT: simulation of the movement of crowns and roots of each tooth for the manufacture of individual caps for the treatment of dental pathologies of patients based on the calculated individual 3D model of the patient's jaws, containing accurate models of each tooth.

This technical result is achieved thanks to a computer-implemented method for constructing a model of teeth, which contains the steps in which:

receiving patient data, which includes a digital 3D model of the crowns of the teeth and adjacent gums, and a computed tomography (CT) scan of the oral cavity;

the region with the jaw is automatically allocated on CT and the teeth with roots are segmented, as a result of which, an image of the root system of the teeth and the surrounding tissue is formed for the upper and lower jaws;

carry out automatic marking of the teeth on the obtained image of the root system and receive separate digital 3D models of the roots of the teeth separately, as well as at least 3D models of bone and soft tissues;

a 3D model of teeth is obtained by combining the models of roots and corresponding crowns, a 3D model of the jaw is formed based on the obtained 3D models of teeth and at least 3D models of bone and soft tissues.

In a private embodiment of the proposed method, CT of the oral cavity contains data on bone tissue, jaw bone thickness and the location of the roots of the teeth.

In another particular embodiment of the proposed method, convolutional neural networks are used when segmenting the roots of teeth on CT.

In another particular embodiment of the proposed method, the transformation of images into a digital 3D model is implemented using the marching cubes algorithm.

In another particular embodiment of the proposed method, a dental arch is found that defines and describes the shape of the jaw.

In another particular embodiment of the proposed method, an orthogonal projection of all identified pixels onto the dental arch is performed;

calculate the total intensity of the projected pixels at each point of the dental arch;

find the points of the dental arch, at which the total intensity of the projected pixels is minimal;

straight lines are built through these points perpendicular to the dental arch, which allow us to divide the segmentation into individual teeth.

The technical result is also achieved thanks to the system for building a model of teeth, containing, a storage device configured to store data;

at least one processor configured to perform the method of constructing a tooth model according to any one of claims 1-6.

The technical result is also achieved due to the method of orthodontic treatment of the patient with the help of caps, containing the steps, in which:

receiving diagnostic data for the preparation of a treatment plan for the patient, containing the parameters of the movement of the teeth for the treatment of orthodontic pathology;

calculate the trajectory of movement of the teeth on the basis of the treatment plan using the obtained model according to claim 1, taking into account the physiological characteristics of the patient's dentoalveolar apparatus; while the trajectory of the movement of the teeth to the end point can be set in different ways, for example, first the horizontal movement, then the vertical movement, then the rotation, based on the calculated trajectory, determine the number of points of the position of the teeth for their movement, using the teeth models obtained according to claim 1;

form on the basis of the mentioned position of the teeth at each mentioned point the corresponding 3D model of the jaw;

- 2 043155 a cap is made on the basis of the obtained 3D models of the jaw at each mentioned point.

In a private embodiment of the proposed method, the speed of movement of the teeth is set, taking into account the physiological characteristics of the patient's dentoalveolar apparatus.

In another particular embodiment of the proposed method, the cap is made by thermoforming according to 3D-printed models of the jaw.

In another private embodiment of the proposed method, the cap can be made of transparent plastic.

Brief description of the drawings

Fig. 1 is a block diagram of the patient's steps during treatment.

Fig. 2 - an example of cap.

Fig. 3 is a block diagram of the preparation of models of the dentoalveolar system for modeling the movement of teeth on computed tomography.

Fig. 4 is a block diagram of modeling tooth movement.

Fig. 5 - block diagram of the manufacture of caps.

Fig. 6 is a general view of the system for constructing a model of teeth, which implements the claimed method for constructing a model of teeth.

Detailed description of the technical solution

Alignment of teeth without braces in adults is quickly and effectively provided by mouthguards made according to the technology of the claimed invention. Caps work on the same principle as braces: due to pressure, the teeth are gradually shifted to the right place, and this process occurs without pain and other inconveniences. It's just that the cap tightly wraps around the tooth and pushes it, this is a technology that allows you to move your teeth in all directions, i.e. and forward to the center of the dental arch, and back from the center of the dental arch, and up and down, tilts towards the cheek or tongue, towards the center of the dental arch or away from the center, moves the tooth corpusally towards the cheek or towards the tongue - it all depends on whether , what a clinical case, and the bracket is glued to the tooth and pulls it along.

A feature of caps is the use of hypoallergenic and safe materials - very transparent and durable, and digital accuracy of calculation in the manufacture of caps - up to microns. In addition, caps are removable orthodontic appliances. They are not fixed on the teeth like braces and can be removed. This ensures maximum comfort in treatment and gives a certain freedom to the patient. With mouthguards, there is no need to diet and oral hygiene is always better.

Thanks to high-precision 3D modeling, the treatment is fast, efficient and comfortable for the patient.

At the first stage of treatment, patient data are obtained, which include a digital 3D model of the crowns of the teeth and adjacent gums, and a computed tomogram (CT) of the oral cavity.

To obtain a digital 3D model of the crowns of the teeth and the adjacent gums, two options can be used: the first is to take casts of the patient's teeth and send them to the laboratory. In the laboratory, plaster models are cast from the casts, the models are scanned and a digital 3D model of the crowns of the teeth and the adjacent gums is created. The second option is to create a digital 3D model of teeth obtained by intraoral scanning, which is performed by a doctor. Intraoral scanning is performed by optical scanning using laser equipment. A dental scan provides information only about the crown part of the tooth and the adjacent gum.

A CT scan of the patient's oral cavity is loaded onto the computer and automatically, using the algorithm of specialized software, it is the area with the jaw that is selected for CT, after which the segmentation of the teeth with roots occurs.

For segmentation (isolation) of teeth with roots, a computer vision system based on convolutional neural networks is used and is carried out as follows: groups of pixels characterizing the roots of teeth are identified on the tomogram.

A window of a given size is built around each pixel. The neural network classifies each block of pixels corresponding to this window into two classes (tooth and non-tooth) and assigns the corresponding label to the central pixel in the block. The operation is performed in each layer of the 3D array and in at least one projection. After that, according to the resulting segmentation, all pixels that were classified as not a tooth are cut off from the original 3D array. The resulting volume is divided into two parts, corresponding to the upper and lower jaws. For each of the jaws, on the slice found by the algorithm, the teeth are automatically marked by the following method: a dental arch is found that defines and describes the jaw (approximation by the least squares method, least square fitting), an orthogonal projection of all pixels characterizing the tooth is made onto the tooth the dental arch and their total intensity is calculated at each point of the dental arch, there are points of the dental arch at which the total intensity of the projected pixels is minimal, straight lines are built through these points perpendicular to the dental arch, segmentation is divided into individual teeth along the straight lines, connected components are distinguished between the straight lines and are marked with a label of an individual tooth, after which the teeth of the obtained image of the root system are automatically marked and digital 3D models of the roots of each tooth are obtained separately, as well as at least 3D models

- 3 043155 bones and soft tissues.

The root model obtained from CT is combined with the corresponding crown obtained by digital scanning, and a 3D model of the tooth is obtained and so on for each tooth of the patient.

As a result, a 3D model of the jaw is formed based on the obtained 3D models of teeth and at least 3D models of bone and soft tissues.

Diagnostic data is loaded to automatically generate a tooth alignment script and a patient treatment plan containing tooth movement parameters for orthodontic pathology treatment. After that, the trajectory of the movement of the teeth is calculated based on the treatment plan using the obtained 3D model of the teeth, taking into account the physiological characteristics of the patient's dentition.

In this case, the trajectory of teeth movement to the end point, namely the final goal of orthodontic treatment, can be set in different ways, for example, first horizontal movement, then vertical, then rotation.

The accuracy of calculating the movement of each tooth is measured in microns. This means that each tooth will move as it was programmed (provided by the treatment plan) and the patient will receive a guaranteed treatment result if the cap is worn for at least 22 hours a day.

Based on the calculated trajectory, the number of teeth position points for their movement is determined using 3D models of the teeth, a corresponding 3D model of the jaw is formed based on the said position of the teeth at each mentioned point, and a cap is made based on the obtained 3D models of the jaw at each mentioned point.

Using real roots to simulate tooth movement allows avoiding anatomically impossible movements when modeling a treatment plan, for example, root collision, root decussation, root movement into dense areas of bone tissue, sinuses - these movements cannot be predicted when modeling tooth movement based only on a crown scan.

When the treatment plan is approved, the entire course of treatment will be divided into two-week stages. Each stage has its own simulated pair of caps. Mouthguards are made by thermoforming from models made using high-precision 3D printing.

This technical solution in its various embodiments can be implemented as a method implemented on a computer, in the form of a system or a machine-readable medium containing instructions for performing the above method.

In some embodiments, the technical solution may be implemented as a distributed computer system.

In FIG. 6 shows a general view of the system (100), which implements the claimed method for constructing a model of teeth.

The tooth model building system (100) can be implemented on the basis of a wide range of electronic computing devices, for example, a personal computer, a laptop, a server cluster, and the like.

In general, the system (100) includes one or more processors (101) that perform the main computational work in implementing the steps of the method.

Random Access Memory (RAM) (102) for online storage of instructions executed by one or more processors (101).

The storage medium (103) may be a hard disk drive (HDD), solid state drive (SSD), flash memory (NAND-flash, EEPROM, Secure Digital, etc.), optical disk (CD, DVD, Blue Ray) , mini disk or combinations thereof.

Input/output (I/O) interfaces (104) are standard ports and means of interfacing devices and data, selected based on the required configuration of the system execution (200), in particular: USB (2.0, 3.0, USB-C, micro, mini), Ethernet, PCI, AGP, COM, LPT, PS/2, SATA, Fire Wire, Lightning, etc.

I/O facilities (105) are also selected from a known range of different devices, e.g. keyboard, touchpad, touch screen, monitor, projector, mouse, joystick, trackball, light pen, stylus, audio output devices (speakers, headphones, built-in speakers). , buzzer), etc.

Data transmission means (106) are selected from devices designed to implement the process of communication between various devices via wired and / or wireless communication, in particular, such devices can be: GSM modem, Wi-Fi transceiver, Bluetooth or BLE module, GPS module, Glonass module, NFC, Ethernet module, etc.

The components of the system (100) are coupled via a common data bus (110).

Program - a sequence of instructions intended for execution by a computer control device or a command processing device.

Modifications and improvements to the above described embodiments of the present technology will be apparent to those skilled in the art. The foregoing description is provided by way of example only and is not intended to be limiting in any way. Thus, the scope of the present technology is limited only by the scope of the appended claims.

Claims (11)

1. A computer-implemented method for constructing a model of teeth, containing the steps at which: receiving patient data, which includes a digital 3D model of the crowns of the teeth and adjacent gums, and a computed tomography (CT) scan of the oral cavity; automatically highlight the area with the jaw on CT and segment the teeth with roots, resulting in an image of the root system of the teeth and the surrounding tissue for the upper and lower jaws; carry out automatic marking of each of the teeth on the obtained image of the root system and receive separate digital 3D models of the roots of the teeth separately, as well as at least 3D models of bone and soft tissues; a 3D model of the teeth is obtained by combining the models of the roots and their corresponding crowns; forming a 3D model of the jaw based on the obtained 3D models of teeth and at least 3D models of bone and soft tissues. 2. The method according to claim 1, characterized in that CT of the oral cavity contains data on bone tissue, jaw bone thickness and the location of the roots of the teeth. 3. The method according to claim 1, characterized in that when segmenting the roots of teeth on CT, convolutional neural networks are used. 4. The method according to claim 1, characterized in that the conversion of images into a digital 3D model is implemented using the marching cubes algorithm. 5. The method according to claim 1, characterized in that a dental arch is found that defines and describes the shape of the jaw. 6. The method according to claim 5, characterized in that an orthogonal projection of all identified pixels onto the dental arch is made; calculate the total intensity of the projected pixels at each point of the dental arch; find the points of the dental arch at which the total intensity of the projected pixels is minimal; straight lines are built through these points perpendicular to the dental arch, which allow us to divide the segmentation into individual teeth. 7. A system for building a model of teeth, containing a storage device configured to store data; at least one processor configured to perform the method of constructing a tooth model according to any one of claims 1-6. 8. A method for orthodontic treatment of a patient using caps, comprising the steps of: receiving diagnostic data for the preparation of a treatment plan for the patient, containing the parameters of the movement of the teeth for the treatment of orthodontic pathology; calculate the trajectory of movement of the teeth on the basis of the treatment plan using the obtained model according to claim 1, taking into account the physiological characteristics of the patient's dentoalveolar apparatus; while the trajectory of the movement of the teeth to the end point can be set in different ways: horizontal movement, vertical movement, rotation; on the basis of the calculated trajectory determine the number of points of the position of the teeth to move them, using the model of the teeth obtained according to claim 1; form on the basis of the mentioned position of the teeth at each mentioned point the corresponding 3D model of the jaw; a cap is made on the basis of the obtained 3D models of the jaw at each mentioned point. 9. The method according to claim 8, characterized in that the speed of movement of the teeth is set, taking into account the physiological characteristics of the patient's dentoalveolar apparatus. 10. The method according to claim 8, characterized in that the cap is made by thermoforming according to 3D-printed models of the jaw. 11. The method according to claim 10, characterized in that the mouth guard can be made of transparent plastic.