Preparation method of nickel-titanium alloy root canal file

Abstract

This application relates to the technical field of root canal file preparation, aiming to solve the problem that it is difficult to efficiently obtain nickel-titanium alloy root canal files with appropriate structural performance requirements by existing processing and manufacturing technologies, and provides a nickel-titanium alloy root canal file combination and a preparation method for nickel-titanium alloy root canal files. By preparing the nickel-titanium alloy root canal file combination, multiple root canal files can be formed at one time. The steps for preparing the nickel-titanium alloy root canal file combination include a powder laying step and a laser scanning step. The laser scanning step is to perform a first laser scanning heating on the laid nickel-titanium alloy powder according to the first process parameters to form an outer ring part and a connecting rib part; perform a second process scanning heating and laser remelting to form a core part. After forming, the nickel-titanium alloy root canal file can be obtained through cutting processing. The beneficial effect of this application is that the nickel-titanium alloy root canal file has both the performance of a flexible core and high hardness on the outside and high processing efficiency.

Description

Technical Field

[0001] This application relates to the technical field of root canal file preparation. Specifically, it relates to a nickel-titanium alloy root canal file assembly and a method for preparing a nickel-titanium alloy root canal file. Background Art

[0002] A root canal file is a tool used for root canal treatment. As a material with high elasticity and memory function, nickel-titanium alloy has greater advantages than stainless steel.

[0003] Additive manufacturing (such as selective laser additive manufacturing technology) is a short-process preparation process, which has great application prospects because its manufacturing cost is significantly reduced compared with conventional subtractive or isostatic processes such as casting / extrusion / drawing.

[0004] However, for nickel-titanium alloy root canal files, due to the special nature of the material and the special requirements of the root canal file itself for structural performance, the conventional processes in existing additive manufacturing technologies cannot be directly applied; or rather, the existing additive manufacturing technologies cannot obtain nickel-titanium alloy root canal files that meet the requirements of structural performance. Summary of the Invention

[0005] This application aims to provide a nickel-titanium alloy root canal file, its assembly, and a preparation method to solve the problem that it is difficult to obtain nickel-titanium alloy root canal files that meet the requirements of appropriate structural performance by existing additive manufacturing technologies.

[0006] The embodiments of this application are implemented as follows:

[0007] This application provides a nickel-titanium alloy root canal file assembly, which includes a plurality of nickel-titanium alloy root canal files and a plurality of connecting ribs. The plurality of nickel-titanium alloy root canal files are distributed in a plane in the distribution plane, and the distribution plane is a plane perpendicular to the axial direction of the nickel-titanium alloy root canal file. The plurality of connecting ribs are used to connect the plurality of nickel-titanium alloy root canal files together to form the nickel-titanium alloy root canal file assembly. Among them, the nickel-titanium alloy root canal file includes a core part and an outer ring part. The core part is made of nickel-titanium alloy; the outer ring part is made of nickel-titanium alloy and is integrally fused to the outer periphery of the core part. The cross-section of the core part is circular, and the cross-section of the outer ring part is a concentric annular structure concentrically covering the core part, so that the core part and the outer ring part form a concentric circular covering structure.

[0008] In this solution, since the nickel-titanium alloy root canal file assembly includes a plurality of nickel-titanium alloy root canal files connected by connecting ribs, multiple nickel-titanium alloy root canal files can be obtained by one printing. And each root canal file is set to have a structure in which the inner core and the outer ring part of the nickel-titanium alloy are concentrically covered, which is convenient to set different printing process parameters for the core part and the outer ring part through 3D printing technology to achieve different internal and external structural performances.

[0009] The present application also provides a method for preparing a nickel-titanium alloy root canal file, which is characterized by including the preparation of the aforementioned nickel-titanium alloy root canal file assembly. The preparation of the nickel-titanium alloy root canal file assembly includes the following steps:

[0010] Powder spreading step: spreading a layer of nickel-titanium alloy powder on a forming base;

[0011] Laser scanning step: performing a first laser scanning heating on the spread nickel-titanium alloy powder according to a first process parameter to scan and heat the nickel-titanium alloy powder within a first range, so that the nickel-titanium alloy powder within the scanned and heated range fuses and cools to obtain a solidified first thin layer; the first range is a combined range of the outer ring parts of each nickel-titanium alloy root canal file and the range where the connecting ribs are located; then, performing a second laser scanning heating on the spread nickel-titanium alloy powder according to a second process parameter to scan and heat the nickel-titanium alloy powder in the inner region within the range of each outer ring part, so that the nickel-titanium alloy powder within the scanned and heated range fuses and cools to obtain a solidified core thin layer; maintaining the second process parameter to perform a laser remelting scan on the core thin layer; wherein, the scanning speed in the first process parameter is faster than the scanning speed in the second process parameter;

[0012] After completing the remelting scan, repeat the powder spreading step and the laser scanning step until the printing of the nickel-titanium alloy root canal file assembly is completed.

[0013] In one embodiment:

[0014] In the first process parameter, the laser power is 270W and the scanning speed is 1900mm / s;

[0015] In the second process parameter, the laser power is 270W and the scanning speed is 1700mm / s.

[0016] In one embodiment:

[0017] In the powder spreading step, the thickness of each layer of the spread nickel-titanium alloy powder is 30μm to 50μm.

[0018] In one embodiment:

[0019] It further includes performing wire cutting on the prepared nickel-titanium alloy root canal file assembly to cut and grind and polish one by one from the nickel-titanium alloy root canal file assembly to obtain a plurality of the nickel-titanium alloy root canal files.

[0020] In one embodiment:

[0021] Spiral cutting edges are processed on the polished nickel-titanium alloy root canal files.

[0022] The method for preparing a nickel-titanium alloy root canal file in this embodiment can prepare multiple nickel-titanium alloy root canal files at one time. This method for preparing a nickel-titanium alloy root canal file is actually an application of selective laser melting technology for forming a nickel-titanium alloy root canal file with a specific material and structure. In this method, by separately laser scanning and heating the outer ring range and its inner area, and after the core thin layer in the inner range is condensed and formed, laser remelting is carried out, and with the above process parameters of different inner and outer scanning speeds, more laser energy can be obtained in the formed core, the core cools more slowly, so that the core has greater toughness while the outer ring part maintains greater hardness; the laser remelting scan also further facilitates the integral fusion of the outer ring part and the core at the junction. Description of the Drawings

[0023] To more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can also be obtained based on these drawings without creative efforts.

[0024] Figure 1 Structural schematic diagram of the nickel-titanium alloy root canal file assembly in the embodiment of the present application;

[0025] Figure 2 For Figure 1 Enlarged view at B of

[0026] Figure 3 Structural schematic diagram of the nickel-titanium alloy root canal file prepared by the method for preparing a nickel-titanium alloy root canal file in the embodiment of the present application after the first laser scanning and heating;

[0027] Figure 4 Structural schematic diagram of the nickel-titanium alloy root canal file in the embodiment of the present application;

[0028] Figure 5 For Figure 4 Cross-sectional view of the nickel-titanium alloy root canal file along line A-A of

[0029] Main element symbol description:

[0030] Nickel-titanium alloy root canal file 10

[0031] Working part 11

[0032] Neck 12

[0033] Shank 13

[0034] Core 10a

[0035] Outer ring part 10b

[0036] Connecting rib 30

[0037] Nitinol root canal file assembly 50

[0038] Inner region Q1 Detailed implementation manners

[0039] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0040] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. When an element is considered to be "disposed on" another element, it can be directly disposed on the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this application belongs. The terms used in the description of the present application herein are only for the purpose of describing specific implementation manners and are not intended to limit the present application. The term "or / and" used herein includes any and all combinations of one or more of the related listed items.

[0042] Some implementation manners of the present application will be described in detail. Without conflict, the following implementation manners and the features in the implementation manners can be combined with each other.

[0043] Embodiment

[0044] With reference to Figure 1 and Figure 2 , the embodiment of the present application provides a Nitinol root canal file assembly 50, which includes a plurality of Nitinol root canal files 10 distributed in a plane within a distribution plane and several connecting ribs 30. The distribution plane is a plane perpendicular to the axis of the Nitinol root canal file; the connecting ribs 30 are used to connect the plurality of Nitinol root canal files together to form an assembly. In this embodiment, the connecting ribs 30 and the outer ring portion 10b are integrally printed and formed.

[0045] The Nitinol root canal file 10 proposed in the embodiment of the present application is mainly used to remove the nerves in the tooth root to fill other substances to prevent the inflammation from spreading further. See Figure 4, its structure generally consists of a working part 11 with a spiral cutting edge, a neck 12, and a shank 13. Among them, the shank is used to connect to a driving member to transmit rotation, and the neck is connected between the working part and the shank. The diameter of a nickel-titanium alloy root canal file generally refers to the maximum outer diameter of the working part, which is generally equal to the diameter of the neck.

[0046] As a material with high elasticity and memory function, nickel-titanium alloy has greater advantages than stainless steel. Its elasticity is 2-3 times that of stainless steel files, and it is not easy to break. It also has good corrosion resistance. However, considering that the root canal file itself requires both flexible deformation ability and the hardness and sharpness of the cutting edge, the known additive manufacturing methods are difficult to achieve quickly and reliably.

[0047] The nickel-titanium alloy root canal file preparation method provided by the embodiments of the present application can prepare a nickel-titanium alloy root canal file with both flexible deformation ability and the hardness of the cutting edge.

[0048] See in conjunction with Figure 5 , the nickel-titanium alloy root canal file of this embodiment includes a core part 10a and an outer ring part 10b. The core part is made of nickel-titanium alloy; the outer ring part is made of nickel-titanium alloy and is integrally fused to the outer periphery of the core part. Optionally, the cross-section of the core part is circular, and the cross-section of the outer ring part is a concentric annular structure concentrically covering the core part, so that the core part and the outer ring part form a concentric circular covering structure. Optionally, the diameter of the core part is 1.2 mm, and the outer diameter of the outer ring part is 1.5 mm; the diameter of the core part and the outer diameter of the outer ring part refer to the diameters of their cross-sections at the neck. Optionally, the length of the nickel-titanium alloy root canal file can be 100 mm, and the length refers to the total length of the nickel-titanium alloy root canal file (including the total length of the working part, neck, and shank). Both the core part and the outer ring part in this embodiment are fused from nickel-titanium alloy powder.

[0049] Furthermore, the working part 11 of the nickel-titanium alloy root canal file is a spiral cone. It can be imagined that the shape of the core part can also be a cone.

[0050] The surface distribution mode of the nickel-titanium alloy root canal file can be matrix distribution or circumferential distribution. For example Figure 1As shown, the Ni-Ti alloy root canal files are distributed in a matrix, and connecting ribs are arranged between adjacent Ni-Ti alloy root canal files to connect them together, making the Ni-Ti alloy root canal file assembly roughly in a grid shape. Each Ni-Ti alloy root canal file is located at the intersection of the grid. The distribution quantity can be 3 in the horizontal row and 10 in the vertical row, 20 in the horizontal row and 10 in the vertical row, 40 in the horizontal row and 20 in the vertical row, etc., but is not limited to the above arrangements; the overall external dimension can be 15mm*30mm*100mm, 30mm*30mm*100mm, 30mm*60mm*100mm, 60mm*90mm*100mm, 90mm*90mm*100mm, but is not limited to the above dimensions. In other embodiments, the overall external shape of the Ni-Ti alloy root canal file assembly can also be circular or other shapes.

[0051] The Ni-Ti alloy root canal file assembly has multiple Ni-Ti alloy root canal files, which is convenient for preparing multiple Ni-Ti alloy root canal files by one-time printing and improves the processing efficiency of a single Ni-Ti alloy root canal file.

[0052] The Ni-Ti alloy root canal file preparation method provided by the embodiment of the present application includes preparing the aforementioned Ni-Ti alloy root canal file assembly. The preparation of the Ni-Ti alloy root canal file assembly includes the following steps:

[0053] Powder spreading step: spreading a layer of Ni-Ti alloy powder on the forming base.

[0054] Laser scanning step: performing first laser scanning heating on the spread Ni-Ti alloy powder according to the first process parameters to scan and heat the Ni-Ti alloy powder within the first range, so that the Ni-Ti alloy powder within the scanned and heated range melts and cools to obtain a solidified first thin layer; the first range is the combined range of the outer ring parts of each Ni-Ti alloy root canal file and the range where the connecting ribs are located; for the structure after the first laser scanning heating, see Figure 5 ; then, performing second laser scanning heating on the spread Ni-Ti alloy powder according to the second process parameters to scan and heat the Ni-Ti alloy powder in the inner region Q1 within each outer ring range, so that the Ni-Ti alloy powder within the scanned and heated range melts and cools to obtain a solidified core thin layer; maintaining the second process parameters to perform laser remelting scanning on the core thin layer; wherein, the scanning speed in the first process parameters is faster than the scanning speed in the second process parameters. For the structure after the second laser scanning and laser remelting, see Figure 3 ;

[0055] After completing the remelting scanning, repeat the powder spreading step and the laser scanning step until the printing of the Ni-Ti alloy root canal file assembly is completed.

[0056] The method for preparing nickel-titanium alloy root canal files in this embodiment can prepare multiple nickel-titanium alloy root canal files at one time. This method for preparing nickel-titanium alloy root canal files is actually an application of selective laser melting technology for forming nickel-titanium alloy root canal files with specific materials and structures. In this method, by separately laser scanning and heating the outer ring range and its inner area, and after the core thin layer in the inner range is condensed and formed, laser remelting is carried out, and with the above process parameters of different inner and outer scanning speeds, the core formed can obtain more laser energy, the core cools slower, so that the core has greater toughness, while the outer ring part obtains less energy and cools faster, maintaining greater hardness; in addition to enabling the core to obtain more energy to further reduce the overall cooling speed of the core, the laser remelting scan also further facilitates the integral fusion of the outer ring part and the core at the junction.

[0057] Optionally, the method for preparing the nickel-titanium alloy root canal file assembly further includes wire cutting the prepared nickel-titanium alloy root canal file assembly to cut off the nickel-titanium alloy root canal files on the nickel-titanium alloy root canal file assembly one by one and polishing them. Each obtained nickel-titanium alloy root canal file 10 can be processed with a spiral cutting edge on the working part through a rolling cutting device.

[0058] This preparation method can print multiple nickel-titanium alloy root canal files at one time, improving the processing efficiency of a single nickel-titanium alloy root canal file.

[0059] Based on the above description, the embodiment of the present application can obtain nickel-titanium alloy root canal files with a flexible interior, a hard exterior, and sharp cutting edges through 3D printing technology with a special process; and this 3D printing technology can print a nickel-titanium alloy root canal file assembly composed of multiple nickel-titanium alloy root canal files at one time, with high preparation efficiency.

[0060] The above embodiments are only used to illustrate the technical solutions of the present application and not to limit them. Although the present application has been described in detail with reference to the above preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A preparation method of a nickel-titanium alloy root canal file, characterized in that, Including the preparation of a nickel-titanium alloy root canal file assembly; the nickel-titanium alloy root canal file assembly includes: A plurality of nickel-titanium alloy root canal files, and the plurality of nickel-titanium alloy root canal files are distributed in a plane in a surface distribution, and the distribution plane is a plane perpendicular to the axial direction of the nickel-titanium alloy root canal file; A plurality of connecting ribs for connecting the plurality of nickel-titanium alloy root canal files together to form the nickel-titanium alloy root canal file assembly; Wherein, the nickel-titanium alloy root canal file includes a core part and an outer ring part, and the core part is made of nickel-titanium alloy; the outer ring part is made of nickel-titanium alloy and is integrally fused to the outer periphery of the core part; The cross-section of the core part is circular, and the cross-section of the outer ring part is a concentric annular structure concentrically covering the outside of the core part, so that the core part and the outer ring part form a concentric circle covering structure; The preparation of the nickel-titanium alloy root canal file assembly includes the following steps: Powder spreading step: Spreading a layer of nickel-titanium alloy powder on a forming base; Laser scanning step: Performing first laser scanning heating on the spread nickel-titanium alloy powder according to the first process parameters to scan and heat the nickel-titanium alloy powder within the first range, so that the nickel-titanium alloy powder within the scanned heating range melts and cools to obtain a solidified first thin layer; the first range is a combined range of the ranges where the outer ring parts of each nickel-titanium alloy root canal file are located and the ranges where the connecting ribs are located; then, performing second laser scanning heating on the spread nickel-titanium alloy powder according to the second process parameters to scan and heat the nickel-titanium alloy powder in the area inside the ranges where each outer ring part is located, so that the nickel-titanium alloy powder within the scanned heating range melts and cools to obtain a solidified core thin layer; maintaining the second process parameters to perform laser remelting scanning on the core thin layer; wherein, the scanning speed in the first process parameters is faster than the scanning speed in the second process parameters; After completing the remelting scanning, repeat the powder spreading step and the laser scanning step until the printing of the nickel-titanium alloy root canal file assembly is completed; In the first process parameters, the laser power is 270W and the scanning speed is 1900mm / s; In the second process parameters, the laser power is 270W and the scanning speed is 1700mm / s; In the powder spreading step, the thickness of each layer of the spread nickel-titanium alloy powder is 30μm to 50μm.

2. The method for preparing a nickel-titanium alloy root canal file according to claim 1, characterized in that: It further includes wire cutting the prepared nickel-titanium alloy root canal file assembly to cut off and polish each one from the nickel-titanium alloy root canal file assembly to obtain a plurality of the nickel-titanium alloy root canal files.

3. The method for preparing a nickel-titanium alloy root canal file according to claim 2, characterized in that: Processing a spiral cutting edge on the polished nickel-titanium alloy root canal file.

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