CN110742704A

CN110742704A - Embedded guide plate for accurately positioning root canal, preparation method and preparation system thereof, application thereof and accurate positioning method of root canal

Info

Publication number: CN110742704A
Application number: CN201910259878.XA
Authority: CN
Inventors: 刘锐
Original assignee: Chinese Peoples Liberation Army Army Specialized Medical Center
Current assignee: Chinese Peoples Liberation Army Army Specialized Medical Center
Priority date: 2019-04-02
Filing date: 2019-04-02
Publication date: 2020-02-04
Anticipated expiration: 2039-04-02
Also published as: CN110742704B

Abstract

The invention discloses a method for preparing an embedded guide plate for accurately positioning an embedded root canal, which comprises the steps of simulating a scene of accurately matching a surgical instrument with a target root canal in a target tooth by constructing a corresponding three-dimensional model to obtain a preoperative planned path of the surgical instrument, then obtaining relevant parameters of the embedded guide plate for accurately positioning the target root canal according to the preoperative planned path, and then preparing the embedded guide plate according to the relevant parameters. Correspondingly, the invention also provides a root canal accurate positioning guide plate, a preparation system and an application thereof, and a root canal accurate positioning method.

Description

Embedded guide plate for accurately positioning root canal, preparation method and preparation system thereof, application thereof and accurate positioning method of root canal

Technical Field

The invention relates to the technical field, in particular to an embedded guide plate for accurately positioning a root canal in root canal treatment, a preparation method, a preparation system and application thereof, and an accurate root canal positioning method, and relates to an oral auxiliary medical instrument.

Background

Endodontic and periapical diseases are common and frequently encountered diseases in oral clinical work, and the most effective treatment means at present is root canal treatment. The principle of root canal therapy is to thoroughly clean, shape and sterilize a complicated root canal system of a tooth and tightly fill the root canal with a filling material, thereby preventing recurrence of infection. Successful root canal treatment requires a thorough understanding of the root canal system, no omission of any root canal, thorough cleaning of the root canal, proper shaping, tight three-dimensional filling. Failure of root canal treatment is often attributed to insufficient knowledge of the anatomy of the root canal, or insufficient knowledge of the travel and bending of the root canal, which in turn leads to root canal omission, root canal underfilling, instrument separation (broken root canal), and the like. Therefore, the structural characteristics of the root canal system are skillfully mastered, which is of great significance for improving the success rate of the root canal treatment.

The main ways to understand root canal systems are by X-ray film technology and CBCT technology. Among them, CBCT is an emerging oral CT in recent years, which employs low-energy cone beam-like radiation, performs three-dimensional morphological analysis of teeth from a sagittal plane, a coronal plane, and a transverse plane by rotational imaging around a part to be imaged of a patient, and allows an oral practitioner to know about the shape, number, orientation, apical condition, and the like of a root canal and a root canal by calling three-dimensional images of each layer and direction, and thus, the CBCT technique is becoming a new favorite of the oral practitioner.

However, the CBCT three-dimensional image before the root canal operation is only a display of the root canal system, which is helpful for the physician to understand the root canal system, but cannot provide intraoperative navigation and guidance for the operator, that is, the current root canal treatment still depends on the deep understanding of the root canal system in the target tooth to be treated by the operator, and then the root canal treatment is performed by using the "free hand" in combination with the microscope, which causes the following two problems:

1) the operator must be trained strictly to perform the root canal treatment under a microscope, and meanwhile, the operator must have abundant clinical experience to avoid iatrogenic injuries such as bottom perforation, lateral perforation of the root canal, fracture of the root canal treatment instrument and the like caused by 'free hands';

2) root canal omission still can occur under a microscope view, and especially when the root canal is changed, namely the position of the root canal orifice and/or the axial direction of the root canal changes, the 'free hand' is more difficult to accurately find the position of the changed root canal.

The above problems all lead to an increased risk of failure of the endodontic treatment. In view of the above problems, there is proposed a CBCT, an oral (optical) scanner and a 3D printing technique combined together for root canal treatment, such as chinese patent application CN201710436728.2, which discloses a treatment guide plate for root canal treatment and a method for manufacturing the same, wherein a guide plate capable of avoiding a dental mechanics support is manufactured by using the CBCT, the oral (optical) scanner and the 3D printing technique, so that an operator can directly perform a pulp opening on the guide plate covering the surface of the guide plate, and then a root canal treatment instrument enters the root canal through a guide hole on the guide plate, so that a doctor can perform more precise and minimally invasive operation, thereby greatly shortening the treatment time and making the treatment result more controllable. However, since the guide plate is directly covered on the surface of the crown to determine the point of opening the marrow, it is only suitable for the target tooth with undamaged/sound crown and is not suitable for the target tooth with incomplete crown/stump state, and the following problems will occur in the practical application:

1) because the guide plate directly covers the surface of the dental crown, the guide plate can be displaced or even separated from the dental crown no matter in the process of opening the marrow or in the process of cleaning the root canal, and particularly in the process of cleaning the root canal, the drill point is continuously lifted up and down, so that the guide plate is more easily displaced or separated. If the guide plate is separated or displaced, the guide hole is deviated from the root canal orifice, namely, the stability of the full-coverage guide plate is poor, so that the inaccurate positioning in the root canal treatment process can be caused;

2) the fully-covered guide plate is only suitable for anterior teeth such as incisors and the like close to two sides of the midline of the jaw face, and is not suitable for a posterior tooth area. This is because the operation space and the operation visual field are limited due to the limitation of the mouth opening degree of the posterior teeth area, and the full-coverage guide plate has a certain thickness, so if the full-coverage guide plate is applied to the root canal treatment of the posterior teeth, the operation space and the operation visual field are further reduced, thereby affecting the performance of the operator;

3) if the root canal orifice is considered as the point of insertion of the surgical instrument into the root canal, the axial tendency of the root canal will accordingly be considered as the direction of insertion of the surgical instrument. Because the fully-covered guide plate covers the surface of the dental crown, correspondingly, the guide hole channel inside the fully-covered guide plate is also positioned outside the target tooth, no guide exists between the guide hole channel of the guide plate and the root canal orifice, namely, the fully-covered guide plate can only determine the position of the root canal orifice, namely a needle feeding point, but cannot guide a surgical instrument to enter the root canal according to an ideal path, namely, the needle feeding direction of the surgical instrument cannot be uniquely determined, especially when the axial direction of the root canal changes, namely, the fully-covered guide plate cannot realize the full-range guide, so that the surgical instrument cannot be guaranteed to reach the optimal position.

4) As is well known, since a surgical instrument is flexible and easily bends when subjected to resistance, when the surgical instrument enters the medullary cavity through a guide channel without any guidance, the surgical instrument may bend in the medullary cavity by being subjected to resistance of other tissues, and may fail to reach an optimal position, thereby causing iatrogenic injuries such as lateral puncture and bottom puncture.

Disclosure of Invention

In view of the above technical problems, the present invention provides an embedded guide plate for accurately positioning a root canal, which is particularly suitable for accurately positioning a target root canal in a target tooth in a residual crown/root canal state.

In order to solve the technical problems, the invention adopts the technical scheme that:

the utility model provides an embedded baffle of root canal accurate positioning, its is including the embedded inlay that is used for complementing the target tooth of incomplete crown/incomplete root state to and at least one guide channel that is used for accurate positioning target root canal, guide channel runs through the inlay, just guide channel with the accurate correspondence of target root canal in the target tooth.

Further, the pilot hole is coaxial with the target root canal.

Further, the inlay has a thickness of 6-8mm and the diameter of the guide channel is 0.5-0.8, preferably 0.6 mm.

Further, the embedded guide plate also comprises an adhesive part for adhering the inlay to the residual crown/stump of the target tooth, wherein the adhesive part is arranged at the edge of the inlay and is adhered to the residual crown/stump of the target tooth; preferably, the adhesive is a flowable resin.

In a second aspect, the present invention further provides a method for preparing an embedded guide plate for accurately positioning a root canal, comprising the steps of:

respectively constructing a three-dimensional model of a virtual surgical instrument and a complete three-dimensional model of a target tooth containing a residual crown/residual root state of a root canal system;

accurately matching the three-dimensional model of the virtual surgical instrument with a target root canal in the complete three-dimensional model based on a sagittal plane, an occlusal plane and a mesial-distal plane of the complete three-dimensional model to obtain a preoperative planned path of the surgical instrument;

acquiring relevant parameters of an embedded guide plate for accurately positioning a target root canal according to the preoperative planned path and the complete three-dimensional model; the relevant parameters include: the shape and thickness of the inlay used to complete the target tooth, and the overall guide path and diameter of the guide tunnel formed in the inlay by the preoperatively planned path.

Wherein the step of constructing a complete three-dimensional model of the target tooth including a root canal system specifically comprises the steps of:

acquiring hard tissue three-dimensional data of a target tooth in a residual crown/residual root state, preprocessing the hard tissue three-dimensional data and constructing a first three-dimensional model containing a root canal system;

optimizing the first three-dimensional model to obtain a first three-dimensional model with noise removed;

and accurately integrating the optimized first three-dimensional model and the optical three-dimensional model of the target tooth to obtain a complete three-dimensional model of the target tooth.

Further, adopting a Retinex algorithm based on a path to carry out preprocessing on the CBCT image; and/or, building the first three-dimensional model using a region growing algorithm.

Further, optimizing the first three-dimensional model by adopting a K-D tree algorithm.

Further, before optimizing the first three-dimensional model, the preparation method further comprises the steps of:

and (3) performing hole filling on the constructed first three-dimensional model by using a triangular mesh hole filling method based on a Poisson equation.

In a third aspect, based on the above method for preparing an embedded guide plate for accurately positioning a root canal, the present invention further provides a system for preparing an embedded guide plate for accurately positioning a root canal, comprising:

the three-dimensional data acquisition equipment, namely the oral special CBCT, is used for scanning the target tooth in a residual crown/residual root state to obtain the hard tissue three-dimensional data of the target tooth;

the optical scanner is used for scanning the target tooth to obtain three-dimensional data of the surface of the target tooth, namely an optical image of the hard tissue of the tooth body;

the accurate positioning equipment is used for preprocessing the hard three-dimensional data obtained by the three-dimensional data acquisition equipment, constructing a first three-dimensional model containing a root canal system, constructing an optical three-dimensional model according to the optical image (namely the three-dimensional data of the surface of the target tooth), optimizing the constructed first three-dimensional model to obtain a first three-dimensional model without noise, accurately integrating the optimized first three-dimensional model and the optical three-dimensional model to obtain a complete three-dimensional model of the target tooth, and accurately matching a pre-constructed virtual instrument corresponding to the selected surgical instrument with the target root canal in the complete three-dimensional model based on a sagittal plane, an occlusal plane and a near-far middle plane of the complete three-dimensional model to obtain a preoperative planned path of the surgical instrument; then acquiring relevant parameters of an embedded guide plate for accurately positioning a target root canal according to the standard model of the target tooth, the complete three-dimensional model and the preoperative planned path; the relevant parameters include: a thickness of an inlay for embedding a target tooth to complete the target tooth, and a through-the-way guide path and a diameter of a guide tunnel formed in the inlay by the preoperative planned path;

and the model preparation equipment is used for acquiring the related parameters from the accurate positioning equipment and preparing the embedded guide plate according to the related parameters.

The accurate positioning equipment adopts a Retinex algorithm based on a path to preprocess the three-dimensional data; and/or, building the first three-dimensional model using a region growing algorithm.

And the accurate positioning equipment optimizes the first three-dimensional model by adopting a K-D tree algorithm.

Further, the precision positioning equipment is also used for performing hole filling on the constructed first three-dimensional model by adopting a triangular mesh hole filling method of a Poisson equation before optimizing the first three-dimensional model.

In a fourth aspect, the present invention further provides a method for accurately positioning a root canal, comprising the steps of:

respectively constructing a three-dimensional model of a surgical instrument and a complete three-dimensional model of a target tooth containing a residual crown/root state of a root canal system;

accurately matching the three-dimensional model of the surgical instrument with a target root canal in the complete three-dimensional model based on a sagittal plane, an occlusal plane and a mesial plane of the complete three-dimensional model to obtain a preoperative planned path of the surgical instrument;

acquiring relevant parameters of an embedded guide plate for accurately positioning a target root canal according to the preoperative planned path and the complete three-dimensional model; the relevant parameters include: an inlay form and thickness for embedding a target tooth to complement the target tooth, and an overall guide path and diameter of a guide tunnel formed in the inlay by the preoperative planned path;

and preparing an embedded guide plate according to the relevant parameters, embedding the inlay of the embedded guide plate into the residual crown/root of the target tooth to fill the target tooth, and guiding a surgical instrument to accurately enter the target root canal through the whole guide hole in the inlay.

Wherein the step of constructing a complete three-dimensional model of the root canal system containing the target tooth specifically comprises the steps of:

and accurately integrating the optimized first three-dimensional model and the tooth optical three-dimensional model of the target tooth to obtain a complete three-dimensional model of the target tooth.

In a fifth aspect, the invention also provides an application of the preparation system of the embedded guide plate for accurately positioning the root canal in root canal treatment or tooth restoration or tooth implantation.

The invention has the advantages that:

the embedded guide plate can accurately and quickly position the target root canal, accurately guide the surgical instrument to operate in accordance with the direction of the target root canal in the whole process, reduce the risk of iatrogenic injuries such as lateral puncture and bottom puncture, improve the success rate of operations, reduce the chair-side time of dentists and improve the working efficiency; and because of adopting the embedded type, only the dental crown is supplemented, and no additional thickness is caused, thereby providing good operation space and operation visual field for the root canal therapy (especially the root canal therapy of the posterior dental area), simultaneously ensuring the stability of the guide plate, and greatly reducing the risk of displacement or separation from the target tooth caused by being lifted in the operation process.

The method for preparing the embedded guide plate for accurately positioning the root canal simulates the condition that a surgical instrument is matched with a target root canal in a target tooth by constructing a corresponding three-dimensional model so as to obtain a preoperative planned path of the surgical instrument, then obtains relevant parameters, such as shape and thickness, of the embedded guide plate for accurately positioning the target root canal according to the preoperative planned path, the standard three-dimensional model of the target tooth and the optical three-dimensional model of the target tooth, and prepares the embedded guide plate according to the relevant parameters, so that a corresponding personalized embedded guide plate can be prepared for each target tooth, accurate positioning of the target root canal in each target tooth is guaranteed, risks of iatrogenic injuries such as lateral penetration, bottom penetration and the like are reduced, and the success rate of operations is improved; meanwhile, the time beside the chair of the dentist is reduced, and the working efficiency is improved.

The root canal accurate positioning method simulates the matching condition of a surgical instrument and a target root canal in a target tooth by constructing a corresponding three-dimensional model so as to obtain a preoperative planned path of the surgical instrument, then obtains relevant parameters of an embedded guide plate for accurate positioning according to the preoperative planned path, a standard three-dimensional model of the target tooth and an optical three-dimensional model of the target tooth, then prepares the embedded guide plate according to the relevant parameters, then embeds an inlay of the embedded guide plate into the target tooth, and carries out accurate positioning under the whole-course guidance of a guide pore passage in the inlay, thereby ensuring the accurate positioning of the target root canal in each target tooth, reducing the risks of side-threading, bottom threading and other iatrogenic injuries, and improving the success rate of the operation; meanwhile, the time beside the chair of the dentist is reduced, and the working efficiency is improved.

Drawings

FIG. 1 is a schematic flow chart of an embodiment of a method for manufacturing an embedded guide plate for accurately positioning a root canal according to the present invention;

FIG. 2a is a schematic structural view of an embodiment of an embedded guide plate for precise root canal positioning according to the present invention;

FIG. 2b is a schematic view of the inlay of the endodontic precisely positioned insertion guide of FIG. 2a being inserted into a target tooth;

FIG. 3 is a schematic flow chart of a method for manufacturing an embedded guide plate for precise root canal positioning according to another embodiment of the present invention;

fig. 4a and 4b are a CBCT image obtained from the target tooth in the preparation method of fig. 3 and a CBCT image after preprocessing, respectively;

fig. 5 is a schematic diagram of a preoperative planned path of a surgical instrument acquired in the preparation method in fig. 3;

FIG. 6 is a schematic diagram of a frame of an embodiment of a system for preparing a root canal precise positioning embedded guide plate according to the present invention;

fig. 7 is a flowchart illustrating a method for accurately positioning a root canal according to an embodiment of the present invention.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The term is defined as:

variant root canal: the altered root canal herein refers to a root canal in which the root canal opening position of the root canal and/or the centerline direction/axial direction of the root canal changes.

The needle inserting position: the needle insertion position herein refers to an entry point of a surgical instrument into a target root canal in a target tooth through a guide hole in the built-in guide plate herein, that is, a root canal opening position.

The needle inserting direction is as follows: the needle insertion direction in this context refers to a direction in which the surgical instrument enters the target root canal of the target tooth through the guide hole in the built-in guide in this context, that is, a direction in which the instrument enters the target root canal (corresponding to the axial direction of the target root canal) uniquely determined by the guide hole. The guide hole in the embedded guide plate corresponds to the axial direction of the target root canal, and the embedded guide plate has a certain thickness, so that the whole-process guide can be realized, and after the instrument enters the guide hole of the embedded guide plate, the direction of the instrument entering the target root canal is also uniquely determined.

Accurate positioning: accurate positioning in this context means the ability to accurately determine the specific location of the root canal orifice of interest and the root canal axial/centerline direction.

Standard three-dimensional models: the standard three-dimensional model in the present context means that each tooth has a theoretical complete model in medicine, and can be obtained by three-dimensionally scanning one or two of the plaster models of the corresponding teeth of the patient, or by scanning impressions of the teeth, and then inputting the three-dimensional model data of the patient's teeth into a computer-aided system, such as CAD, and then designing the whole tooth restoration or bridge substructure in the CAD, and finally obtaining the standard three-dimensional model of each tooth. This standard three-dimensional model herein is used to perform boolean operations with a complete three-dimensional model of the patient's target tooth, so that the shape and thickness of the inlay in the inlay guide can be derived.

Generally, no matter whether it is a full crown tooth or a specific position of a normal root canal orifice in a residual crown/residual root tooth, the specific position can be found according to medical rules with the aid of a microscope, but once the root canal is mutated, namely, the position of the root canal opening of the root canal and/or the axial direction of the root canal are changed, even with the aid of the microscope, the root canal opening of the root canal is not easy to find, and even if the root canal opening is found, because the axial direction of the root canal is changed, if the operation can not be performed in compliance with the axial direction of the root canal, risks such as side-threading and bottom-threading are likely to be caused, thereby causing iatrogenic.

Based on the above, the present invention provides an embedded guide plate capable of accurately positioning a root canal in a target tooth in a residual crown (partial defect of a crown), and a preparation method, a system and an accurate positioning method thereof, wherein the core ideas of the preparation method of the embedded guide plate and the accurate positioning method of the root canal are as follows: respectively constructing a three-dimensional model (namely constructing a virtual surgical instrument) of a surgical instrument selected by an operator and a complete three-dimensional model containing a target tooth root canal system, and then accurately matching the virtual surgical instrument with a target root canal in the complete three-dimensional model based on a sagittal plane, an occlusal plane and a near-far middle plane of the complete three-dimensional model to obtain a preoperative planned path of the surgical instrument; finally, relevant parameters of an embedded guide plate for accurately positioning the root canal are obtained according to the preoperative planned path, the standard three-dimensional model of the target tooth and the complete three-dimensional model of the target tooth, and the embedded guide plate is prepared according to the relevant parameters, wherein the relevant parameters comprise the shape and the thickness of an inlay of the guide plate and the whole-course guide path and the diameter of a guide hole formed on the inlay by the preoperative planned path, so that when the inlay of the guide plate is embedded on the target tooth, the guide hole naturally corresponds to the target root canal, thereby realizing whole-course guide under the combined action of the inlay and the guide hole, and accurately positioning the target root canal (namely, the guide hole corresponds to the opening position of the target root canal, and the whole-course guide path of the guide hole determines the axial direction of the root canal), specifically, referring to fig. 1: s11, acquiring three-dimensional data of hard tissues (such as crowns, root canals, alveolar bones and the like) of target teeth in a residual crown/residual root state and constructing a corresponding first three-dimensional model (further, in order to avoid root canal omission, the acquired three-dimensional data needs to be preprocessed before the first three-dimensional model is constructed so as to enhance the development degree and definition of the root canal); s12, accurately matching the first three-dimensional model with the optical three-dimensional model of the surface of the target tooth to obtain a complete three-dimensional model; s13, based on the sagittal plane, occlusal plane and mesial-distal plane of the complete three-dimensional model, accurately matching the constructed virtual instrument corresponding to the selected surgical instrument with the target root canal in the complete three-dimensional model, thereby obtaining the preoperative planned path of the surgical instrument, such as the needle insertion position (namely the specific position of the root canal orifice) and the needle insertion direction (which is adapted to the axial direction of the root canal); s14, obtaining relevant parameters of the embedded guide plate for accurately positioning the target root canal according to the pre-stored standard three-dimensional model, the complete three-dimensional model and the preoperative planned path (specifically, performing boolean operation on the optical three-dimensional model, the virtual instrument and the standard three-dimensional model of the target tooth surface in the complete three-dimensional model to obtain a three-dimensional model of the inlay of the embedded guide plate, i.e. a virtual inlay), such as the thickness, the shape, the whole course guide path and the diameter of the guide hole; s15, preparing an embedded guide plate according to the relevant parameters (specifically, preparing the embedded guide plate in a 3D printing mode); so that when the inlay of the embedded guide plate for accurately positioning the root canal is embedded in the residual crown/root canal of the target tooth, the surgical instrument is guided through the guide channel in the inlay to accurately position the target root canal.

The following describes the embedded guide plate for accurately positioning the root canal of a target tooth, and a method, a system and an accurate positioning method for the embedded guide plate according to the present invention in detail with reference to the following embodiments and accompanying drawings.

Example one

Referring to fig. 2a, which is a schematic structural view of an embodiment of an insert guide for accurately positioning root canals according to the present invention, specifically, the insert guide of the present embodiment includes an inlay 11 for completing a target tooth in a residual crown/root canal state, and at least one guide hole 12 corresponding to at least one root canal in the target tooth one by one, wherein the guide hole 12 is located in the inlay 11 and penetrates through the inlay 11.

In this embodiment, the inlay 11 has a thickness of 2-4mm, and the guide hole 12 has a diameter of 0.5-0.8mm, and in one embodiment, the guide hole 12 has a diameter of 0.6 mm.

In this embodiment, since the target tooth is in a stump/stump state, when the inlay of the embedded guide plate for accurately positioning the root canal is embedded into the target tooth, the target tooth is made to be complete, that is, the supplemented target tooth is the same as/similar to the corresponding standard model, and the guide hole in the inlay is directly butted with the target root canal opening in the target tooth after being supplemented, that is, the outlet of the guide hole is butted with the root canal opening of the target root canal, while the axial direction of the guide hole is adapted to the axial direction of the target root canal (the best case is that the guide hole and the target root canal are coaxial), that is, the guide hole and the target root canal are accurately matched, and since the axial directions of the guide hole and the root canal are adapted, and the inlay has a certain thickness, the guide hole can uniquely determine the needle insertion direction and the needle insertion position of the surgical instrument, and perform accurate whole-course.

In order to further ensure the stability and avoid the displacement of the inlay caused by the displacement of the guide hole during the operation, the embodiment also arranges an adhesive part at the edge of the inlay, and the edge of the inlay is adhered to the target tooth through the adhesive part, specifically, the flowing resin is arranged at the edge of the inlay and adhered to the target tooth, and of course, after the operation is completed, the adhesive part and the inlay can be directly moved out from the target tooth together.

Example two

The invention also provides a preparation method of the embedded guide plate for accurately positioning the root canal, which corresponds to the embedded guide plate for accurately positioning the root canal, and the following detailed description is provided by combining specific embodiments and accompanying drawings.

Referring to fig. 3, a flowchart of an embodiment of a method for manufacturing an embedded guide plate for accurately positioning a root canal according to the present invention is shown, and specifically, the method for manufacturing the embedded guide plate according to the present embodiment includes the steps of:

and S31, preprocessing the acquired three-dimensional data of the hard tissue of the target tooth in the residual crown/root state by adopting a Retinex algorithm based on the path.

In a specific embodiment, a CBCT apparatus is used to scan a target tooth to obtain three-dimensional data of a hard tissue of the tooth, such as an alveolar bone, a root canal, etc., and then a path-based Retinex algorithm is used to pre-process the obtained CBCT image, i.e., the three-dimensional data, so as to enhance the developing degree and definition of each root canal in the CBCT image, see fig. 4a and 4b, and thus avoid omission.

S32, constructing a first three-dimensional model of the root canal containing the target tooth according to the preprocessed three-dimensional data and a region growing algorithm.

In a specific embodiment, after the first three-dimensional model is constructed, segmentation of the upper and lower jaws is performed, specifically, further region growing is performed based on the upper and lower jaw segmentation boundary line of the sagittal plane, so as to segment the upper and lower jaws.

S33, hole filling is carried out on the constructed first three-dimensional model by adopting a triangular mesh hole filling method based on a Poisson equation, so that the first three-dimensional model is perfected.

S34, optimizing the first three-dimensional model in the step S33 by adopting a K-D tree algorithm to obtain a first three-dimensional model which removes alveolar bones and the like and leaves root canals.

In this embodiment, the first three-dimensional model is optimized by using a K-D tree algorithm to remove alveolar bone and other noises, thereby avoiding the influence of the noises.

And S35, combining the optimized first three-dimensional model and the optical three-dimensional model of the target tooth to obtain a complete three-dimensional model of the target tooth.

In a specific embodiment, the optical three-dimensional model is obtained by scanning the target tooth with an oral scanner in advance, and after the optical three-dimensional model is obtained, the optical three-dimensional model and the first three-dimensional model in step S34 are introduced into the root canal precise positioning device with the mimics9.0 software installed to perform contour matching, that is, the optical three-dimensional model and the first three-dimensional model are combined, specifically, the feature points are correctly matched from the occlusal plane, the sagittal plane and the mesial-distal plane 3 respectively by a feature point-based matrix transformation method, a transformation matrix is obtained, and the boundary of the target tooth is calculated by the transformation matrix.

And S36, matching the pre-constructed virtual instrument corresponding to the selected surgical instrument with the target root canal in the complete three-dimensional model based on the sagittal plane, the occlusal plane and the near-far plane of the complete three-dimensional model obtained in the step S35, so as to obtain the preoperative planned path of the surgical instrument.

In this embodiment, the preoperative planned path refers to the needle insertion position and needle insertion direction of the virtual instrument obtained after matching the virtual instrument with the target root canal in the complete three-dimensional model of the target tooth, specifically, after an operator selects a corresponding surgical instrument according to the target tooth in advance, a corresponding three-dimensional model, i.e., a virtual instrument, can be constructed according to corresponding parameters of the surgical instrument, such as size, shape and the like, and then the virtual instrument is placed at the matching position of the root canal from the sagittal plane, the occlusal plane and the near-far middle plane respectively according to the observed root canal condition in the complete three-dimensional model, as shown in fig. 5.

And S37, acquiring relevant parameters of the virtual inlay and the guide hole for filling the target tooth according to the pre-stored standard model of the target tooth and the complete three-dimensional model in the step S35.

In a specific embodiment, boolean operations are performed on the standard three-dimensional model and the optical three-dimensional model in the complete three-dimensional model, so as to obtain a defective portion of the target tooth, which is also a relevant parameter of the virtual inlay (i.e., when the standard three-dimensional model and the optical three-dimensional model are combined or compared, a missing portion of the optical three-dimensional model relative to the standard three-dimensional model is a missing portion of the target tooth, which is also a virtual inlay); similarly, boolean operation is performed on the standard model and the virtual instrument, so as to obtain relevant parameters of the guide channel in the virtual inlay (that is, when the standard three-dimensional model and the complete three-dimensional model are precisely matched, the channel formed by the virtual instrument/target root canal in the target root canal of the complete three-dimensional model in the virtual inlay is the guide channel); the relevant parameters (STL format) include, among others, inlay morphology, thickness (2-4mm), overall guide path (e.g. axial) and diameter (0.1-0.6mm) of the guide channel.

And S38, performing 3D printing according to the relevant parameters acquired in the step S37 to obtain the embedded guide plate.

EXAMPLE III

Based on the method for preparing the embedded guide plate for accurately positioning the root canal, the invention also provides a system for preparing the embedded guide plate for accurately positioning the root canal, and the detailed description is given below by combining specific embodiments and accompanying drawings.

Referring to fig. 6, a system framework diagram of an embodiment of a system for preparing a root canal accurate positioning embedded guide according to the present invention is shown, and specifically, the system for preparing a root canal accurate positioning embedded guide of the present embodiment includes:

a three-dimensional data acquisition device 61 for scanning the target tooth in the residual crown/root state to obtain corresponding three-dimensional data of the hard tissue; in one embodiment, a CBCT apparatus is employed to scan a target tooth;

an optical scanner 62 for scanning the target tooth to obtain three-dimensional data of the corresponding target tooth surface;

a precise positioning device 63 connected to the three-dimensional data acquisition device and the oral scanner for preprocessing the three-dimensional data of the hard tissue acquired by the three-dimensional data acquisition device, constructing a first three-dimensional model of the hard tissue including the alveolar bone and the root canal system of the target tooth, constructing an optical three-dimensional model of the tooth surface according to the optical three-dimensional data of the tooth surface scanned by the optical scanner, optimizing the constructed first three-dimensional model to obtain a first three-dimensional model after removing noise (such as alveolar bone), precisely matching the first three-dimensional model with the optical three-dimensional model of the tooth surface to obtain a complete three-dimensional model of the target tooth, and precisely matching a virtual instrument corresponding to a selected pre-constructed surgical instrument with the target root canal in the complete three-dimensional model based on the sagittal plane, occlusal plane and near-far plane of the complete three-dimensional model, obtaining a preoperative planned path of the selected surgical instrument (such as a needle insertion position, namely the root canal orifice position of the target root canal, and a needle insertion direction, namely an entering direction of the surgical instrument into the target root canal, and the like); then obtaining relevant parameters of an embedded guide plate for accurately positioning a target root canal according to the standard model of the target tooth, the complete three-dimensional model and the preoperative planned path; wherein the relevant parameters include: the shape and thickness of the inlay in the embedded guide plate, and the whole navigation path/axial direction and diameter of the guide hole channel corresponding to the preoperative planned path in the inlay; specifically, in this embodiment, the root canal accurate positioning device 63 performs preprocessing on a CBCT image obtained by scanning the CBCT device by using a Retinex algorithm based on a path, constructs a first three-dimensional model of a target tooth by using a region growing algorithm, and optimizes the first three-dimensional model by using a K-D tree algorithm; further, before optimizing the first three-dimensional model, the accurate root canal positioning equipment adopts a triangular mesh hole filling method based on a Poisson equation to fill holes in the first three-dimensional model; of course, before filling the hole, further region growing is carried out based on the upper and lower jaw division boundary line of the sagittal plane to divide the upper and lower jaws;

the model preparation device 64 is connected with the accurate positioning device 63 and is used for preparing according to the relevant parameters of the virtual embedded guide plate acquired by the accurate positioning device 63 to obtain an entity embedded guide plate; in a specific embodiment, the embedded guide plate is printed by using a 3D printing device.

In a specific embodiment, the mimics9.0 software and the finite element analysis software are installed in the precise positioning device 63, that is, data obtained by scanning of the oral cavity scanner and the CBCT device are imported into the mimics9.0 software to perform contour line matching, specifically, corresponding feature points are selected from 3 directions of the occlusal surface, the sagittal surface, and the proximal and distal surfaces respectively by a feature point-based matrix transformation method to be processed, so as to obtain matching results, and then a complete three-dimensional model is obtained; of course, manual adjustment can also be performed after the finite element analysis, so that the two models are more matched.

The preparation system in this embodiment can be applied to dental restoration or dental implant in addition to root canal treatment.

Example four

Based on the method for manufacturing the embedded guide plate for accurately positioning the root canal in the second embodiment and the system for manufacturing the embedded guide plate for accurately positioning the root canal in the third embodiment, the present invention further provides a method for accurately positioning the root canal, and specifically, referring to fig. 7, the method for accurately positioning the root canal in the present embodiment includes the steps of:

and S71, acquiring the hard tissue three-dimensional data of the target tooth in the residual crown/root state, and preprocessing the data.

In a specific embodiment, a CBCT device is used to scan a target tooth to obtain a CBCT image, the CBCT image is imported into the mimics9.0 software, and then the obtained hard tissue three-dimensional data of the target tooth is preprocessed by a path-based Retinex algorithm to increase the developing degree and definition of the root canal of the target tooth.

S72, constructing a first three-dimensional model of the target tooth according to the preprocessed hard tissue three-dimensional data.

In a specific embodiment, the mimics9.0 software adopts a region growing algorithm to extract a corresponding CBCT image from the preprocessed CBCT image for three-dimensional modeling, so as to obtain a first three-dimensional model.

And S73, optimizing the constructed first three-dimensional model to obtain the first three-dimensional model with noise removed.

In one embodiment, the mimics9.0 software uses a K-D tree algorithm to perform chaotic point cloud denoising on the constructed first three-dimensional model to obtain a first three-dimensional model with noise removed, such as alveolar bone.

Further, before optimization, a hole needs to be filled in the first three-dimensional model, and specifically, the mim 9.0 software fills the hole in the first three-dimensional model by using a triangle network hole filling method based on a Poisson equation.

And S74, combining the optimized first three-dimensional model and the optical three-dimensional model of the target tooth to obtain a complete three-dimensional model of the target tooth.

In a specific embodiment, the surface data information of the target tooth acquired by the oral cavity scanner (i.e. the optical scanner) and the preprocessed CBCT image are respectively imported into the mimics9.0 software to obtain corresponding optical three-dimensional models, and the optical three-dimensional models are subjected to contour line matching with the first three-dimensional model, specifically, corresponding feature points are respectively selected from three directions of an occlusal plane, a sagittal plane and a near-far plane, and edges are determined based on a matrix transformation method of the feature points to perform matching. Of course, the final manual adjustment is performed based on the finite element analysis.

And S75, based on the sagittal plane, the occlusal plane and the near-far middle plane of the complete three-dimensional model, accurately matching the virtual instrument corresponding to the pre-constructed surgical instrument with the target root canal in the complete three-dimensional model to obtain the preoperative planned path of the surgical instrument.

In an embodiment, a corresponding three-dimensional model, i.e. a virtual instrument, is previously made according to the size of the selected surgical instrument, then the position of the root canal is observed and located in the complete three-dimensional model based on the sagittal plane, the occlusal plane and the mesial-distal plane, and the virtual instrument is accurately matched with the target root canal to obtain the preoperative planned path of the surgical instrument, such as the needle insertion position and the needle insertion direction, see fig. 5.

S76, obtaining relevant parameters of the embedded guide plate for accurately positioning the root canal according to the standard three-dimensional model and the complete three-dimensional model of the target tooth and the preoperative planned path in the step S75, and then preparing the embedded guide plate according to the relevant parameters.

In this embodiment, the relevant parameters include: the shape and thickness of the inlay, the full navigation path (e.g., axial) and diameter of the guide bore formed within the inlay from the preoperatively planned path of the virtual instrument.

And S77, embedding the inlay of the embedded guide plate into the residual crown/root of the target tooth, and guiding the surgical instrument from the whole course of the inlay inner guide hole to accurately position the target root canal.

The precise positioning method of this embodiment is to pre-process three-dimensional data of hard tooth tissues of a target tooth, such as alveolar bone, root canal, etc., then construct a corresponding first three-dimensional model, optimize the first three-dimensional model, enable the root canal to be more clearly developed, construct a complete three-dimensional model according to an optical three-dimensional model of the target tooth and the first three-dimensional model, match corresponding virtual instruments in the complete three-dimensional model, that is, obtain a preoperative planned path by simulating an insertion position, an insertion direction, etc. of a surgical instrument in advance, and obtain relevant parameters to prepare a corresponding embedded guide plate, so that when the embedded guide plate is embedded into the target tooth, the whole course guidance can be performed through a guide channel in the embedded guide plate to uniquely determine the insertion position and the insertion direction of the surgical instrument, thereby ensuring precise positioning of a root canal for a doctor, the risk of iatrogenic injuries such as side-wearing and bottom-wearing is reduced, the chair-side time of dentists is reduced, and the success rate of operations is improved.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. The utility model provides an embedded baffle of root canal accurate positioning, its characterized in that, is including the inlay that is used for mending the target tooth of incomplete crown/incomplete root canal state to and at least one is used for whole guide surgical instruments with the guide channel of accurate positioning target root canal, the guide channel runs through the inlay, just the guide channel with target root canal in the target tooth is corresponding.

2. The embedded guide of claim 1, wherein the guide channel is precisely matched to the target root canal when the inlay is embedded in the target tooth.

3. The embedded guide plate as set forth in claim 2, wherein the inlay has a thickness of 6-8mm, and the guide hole has a diameter of 0.5-0.8 mm.

4. The method for manufacturing an insert guide according to any one of claims 1 to 3, comprising the steps of:

respectively constructing a three-dimensional model of a surgical instrument and a complete three-dimensional model of a target tooth in a residual crown/residual root state, which comprises a root canal system;

acquiring relevant parameters of an embedded guide plate for accurately positioning a target root canal according to the preoperative planned path and the complete three-dimensional model;

preparing an embedded guide plate according to the relevant parameters;

wherein the relevant parameters include: the shape and thickness of the inlay used to complete the target tooth, and the overall guide path and diameter of the guide tunnel formed in the inlay by the preoperatively planned path.

5. The method for preparing an embedded guide of claim 4, wherein the step of constructing a complete three-dimensional model of the target tooth including a root canal system comprises the steps of:

6. The method for manufacturing an embedded guide plate according to claim 5, wherein the CBCT image is preprocessed by a path-based Retinex algorithm; and/or, building the first three-dimensional model by adopting a region growing algorithm; and/or optimizing the first three-dimensional model by adopting a K-D tree algorithm.

7. The method for manufacturing an embedded guide plate according to claim 5, further comprising, before optimizing the first three-dimensional model, the steps of:

8. The utility model provides a preparation system of embedded baffle of root canal accurate positioning which characterized in that includes:

the three-dimensional data acquisition equipment is used for scanning the target tooth in a residual crown/root state to obtain hard tissue three-dimensional data of the target tooth;

the optical scanner is used for scanning the target tooth to obtain three-dimensional data of the surface of the target tooth;

the accurate positioning equipment is used for preprocessing the three-dimensional data of the hard tissue obtained by the three-dimensional data acquisition equipment, constructing a first three-dimensional model containing a root canal system, constructing an optical three-dimensional model according to the three-dimensional data of the surface of the target tooth, optimizing the constructed first three-dimensional model to obtain a first three-dimensional model without noise, accurately integrating the optimized first three-dimensional model and the optical three-dimensional model of the surface of the tooth to obtain a complete three-dimensional model of the target tooth, and accurately matching a virtual instrument corresponding to a pre-constructed selected surgical instrument with a target in the complete three-dimensional model based on a sagittal plane, an occlusal plane and a near-far middle plane of the complete three-dimensional model to obtain a preoperative planned path of the surgical instrument; then acquiring relevant parameters of an embedded guide plate for accurately positioning a target root canal according to the standard model of the target tooth, the complete three-dimensional model and the preoperative planned path; the relevant parameters include: a shape and thickness of an inlay used to complete the target tooth, and a full-scale guide path and diameter of a guide tunnel formed in the inlay by the preoperative planned path;

9. The manufacturing system of claim 8, wherein the precision positioning device employs a path-based Retinex algorithm to pre-process the three-dimensional data; and/or, building the first three-dimensional model by adopting a region growing algorithm; and/or the precise positioning equipment optimizes the first three-dimensional model by adopting a K-D tree algorithm.

10. The manufacturing system of claim 9, wherein the precision positioning apparatus is further configured to patch the constructed first three-dimensional model using a triangular mesh patch method of Poisson's equation prior to optimizing the first three-dimensional model.

11. A method for accurately positioning a root canal is characterized by comprising the following steps:

respectively constructing a three-dimensional model of a surgical instrument and a complete three-dimensional model of a target tooth containing a residual crown/residual root state of a root canal system;

acquiring relevant parameters of an embedded guide plate for accurately positioning a target root canal according to the preoperative planned path and the complete three-dimensional model; the relevant parameters include: a shape and thickness of an inlay used to complete the target tooth, and a full-scale guide path and diameter of a guide tunnel formed in the inlay by the preoperative planned path;

12. The method for accurately positioning a root canal according to claim 11, wherein the step of constructing a complete three-dimensional model of the root canal system including the target tooth comprises the steps of:

and accurately integrating the optimized first three-dimensional model and the tooth surface three-dimensional model of the target tooth to obtain a complete three-dimensional model of the target tooth.

13. The method of accurately positioning a root canal according to claim 12, wherein the CBCT image is preprocessed using a path-based Retinex algorithm; and/or, building the first three-dimensional model by adopting a region growing algorithm; and/or optimizing the first three-dimensional model by adopting a K-D tree algorithm.

14. The method for accurately positioning a root canal according to claim 13, wherein before optimizing the first three-dimensional model, the method further comprises the steps of:

15. Use of the preparation system according to any one of claims 8 to 10 for endodontic treatment, or dental restoration or dental implantation.