Root canal file and root canal preparation machine
By designing root canal files with multiple shape transitions, the problems of low cutting efficiency and difficulty in chip removal of existing root canal files have been solved, achieving high-efficiency cutting and stability, reducing the risk of instrument breakage, adapting to complex root canal morphologies, and improving surgical precision and flexibility.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHANGZHOU SIFARY MEDICAL TECH CO LTD
- Filing Date
- 2025-04-15
- Publication Date
- 2026-05-08
AI Technical Summary
Existing root canal files have high friction and a small cutting angle between the cutting surface and the dentin surface, resulting in insufficient cutting efficiency. At the same time, the chip capacity is low, and the debris is difficult to expel.
Design an endodontic file with an operating section comprising a first cutting edge and a second cutting edge, the first cutting edge and the second cutting edge having different shapes, at least one being a rhombus or a regular parallelogram, with a smooth transition between the two, the cross-sectional shape gradually transitioning from the tip to the handle, maintaining two-point contact, and incorporating nickel-titanium alloy material and high-temperature heat treatment to enhance rigidity and flexibility.
It improves cutting efficiency and chip removal capacity, reduces the risk of instrument breakage, adapts to different root canal morphologies, reduces operation time, and improves preparation accuracy and flexibility.
Smart Images
Figure CN224206903U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of dental instrument technology, and more specifically, to a root canal file and root canal preparation machine. Background Technology
[0002] Root canal treatment is a common procedure for treating pulpitis and periapical diseases. It can thoroughly remove necrotic nerve tissue and sources of infection while preserving the natural tooth to the greatest extent possible. Machine-operated root canal files are commonly used tools in root canal preparation. They are highly efficient in opening the pulp chamber, cleaning the root canal cavity, and establishing a complete and smooth passage, significantly impacting the effectiveness of root canal treatment.
[0003] Traditional root canal files typically use a fixed cross-sectional shape (such as triangle, square, or rhombus). From a structural perspective, a single cross-sectional shape easily leads to stress concentration during use, causing instrument fatigue and fracture. From a clinical perspective, complex root canal systems require instruments with multiple performance characteristics, which a single cross-sectional shape cannot meet. Existing technologies also include some variable cross-sectional designs, such as a square gradually transitioning to a rectangle. However, these designs generally involve four-point cutting, resulting in high friction and a small cutting angle between the cutting surface and the dentin surface, leading to insufficient cutting efficiency. They also result in a low chip volume, causing chip compression and difficulty in removal. Utility Model Content
[0004] The technical problem to be solved by the present application is that the existing root canal files have high friction and a small cutting angle between the cutting surface and the dentin surface, resulting in insufficient cutting efficiency. At the same time, they also cause a low chip capacity, resulting in chip compression and difficulty in removal.
[0005] To address the aforementioned technical problems, this application provides a root canal file, employing the technical solution described below:
[0006] The root canal file includes a handle and an operating part. The operating part includes a first cutting edge and a second cutting edge. The second cutting edge is disposed between the handle and the first cutting edge. The first cutting edge and the second cutting edge are respectively a regular parallelogram, a rhombus, or a rectangle, and the shapes of the first cutting edge and the second cutting edge are different. At least one of the first cutting edge and the second cutting edge is a rhombus or a regular parallelogram for two-point cutting in the root canal. The first cutting edge and the second cutting edge have a smooth transition.
[0007] Furthermore, the cross-section of the first cutting edge is a rhombus for two-point cutting within the root canal. The four corners of the rhombus are denoted as A1, A2, A3, and A4, respectively. On the rhombus, A1, A2, A3, and A4 are distributed counterclockwise, with A1 and A3 corresponding to each other and A2 and A4 corresponding to each other. The vertices of A1 and A3 are both located on the working circumference T1 of the first cutting edge, while A2 and A4 are located inside the working circumference T1 of the first cutting edge.
[0008] Furthermore, the cross-section of the second cutting edge is rectangular.
[0009] Furthermore, the cross-section of the second cutting edge is a common parallelogram for two-point cutting within the root canal. The four corners of the common parallelogram are denoted as B1, B2, B3, and B4, respectively. On the common parallelogram, B1, B2, B3, and B4 are distributed counterclockwise, with B1 and B3 corresponding to each other and B2 and B4 corresponding to each other. The vertices of B1 and B3 are both located on the working circumference T2 of the second cutting edge, while B2 and B4 are located inside the working circumference T2 of the second cutting edge.
[0010] Furthermore, the cross-section of the first cutting edge is square.
[0011] Furthermore, the length L1 of the first cutting edge is 1-10 mm; and / or,
[0012] The length L2 of the second cutting edge is 4-20 mm; and / or,
[0013] The length L3 of the operating part is 5-40 mm; and / or,
[0014] The diameter of the handle portion is 1-10 mm; and / or,
[0015] The diameter of the operating part gradually decreases in the direction away from the handle part.
[0016] Furthermore, the operating part also includes a smoothing part, which is disposed between the second blade part and the handle part.
[0017] Furthermore, the smooth portion is provided with multiple etched lines, the width of which is 0.1-1 mm; and / or,
[0018] The diameter of the smooth part is 0.1-3 mm.
[0019] Furthermore, the root canal file also includes a limiting part, which is disposed between the handle part and the operating part.
[0020] To address the aforementioned technical problems, this application also provides a root canal preparation machine, which employs the following technical solution, including: the root canal file.
[0021] Compared with the prior art, the present application has the following advantages: The root canal file of the present application absorbs the advantages of ordinary parallelogram cross section and rhombus cross section. From its tip to the handle, the cross section shape of the root canal file gradually transitions from rhombus to ordinary parallelogram. During the cutting process, two-point contact can be maintained, ensuring more chip space. This not only ensures the cutting efficiency and stability of the tip, but also improves the chip removal capability. Attached Figure Description
[0022] To more clearly illustrate the solution of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0023] Figure 1 This is a front view of an embodiment of this application;
[0024] Figure 2 This is a front view of the operating section according to an embodiment of this application;
[0025] Figure 3 This is a cross-sectional view of the first cutting edge according to an embodiment of this application;
[0026] Figure 4 This is a cross-sectional view of the second cutting edge in an embodiment of this application.
[0027] Reference numerals: 100, handle; 200, operating part; 1, first cutting edge; 2, second cutting edge; 3, smooth part; 4, limiting part. Detailed Implementation
[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.
[0029] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0030] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.
[0031] As attached Figure 1 To be continued Figure 4 As shown in the figure, this application provides a root canal file, which includes a handle portion 100 and an operating portion 200. The operating portion 200 includes a first cutting edge 1 and a second cutting edge 2. The second cutting edge 2 is disposed between the handle portion 100 and the first cutting edge 1. The first cutting edge 1 and the second cutting edge 2 are respectively a common parallelogram, a rhombus, or a rectangle, and the shapes of the first cutting edge 1 and the second cutting edge 2 are different. At least one of the first cutting edge 1 and the second cutting edge 2 is a rhombus or a common parallelogram for two-point cutting in the root canal, and there is a smooth transition between the first cutting edge 1 and the second cutting edge 2.
[0032] The root canal file combines the advantages of both ordinary parallelogram and rhomboid cross-sections. From its tip to the handle 100, the cross-sectional shape gradually transitions from a rhomboid to an ordinary parallelogram, maintaining two-point contact throughout the cutting process. This ensures more chip-holding space, guaranteeing both cutting efficiency and stability at the tip, while also improving chip removal capacity and fatigue resistance. The variable cross-section design of the root canal file can adapt to different root canal morphologies and treatment needs, increasing the flexibility of clinical application. It also avoids over-preparation during clinical operations, allowing the original morphology of the root canal apex and middle and posterior segments to be perfectly preserved during preparation, reducing surgical time and improving preparation accuracy. Furthermore, the smooth transition between the first cutting edge 1 and the second cutting edge 2, with a complete helix, reduces stress concentration caused by abrupt changes in cross-sectional shape, lowering the risk of instrument breakage.
[0033] Furthermore, since the root canal file prepares the root canal by cutting through contact with the dentin wall, the cross-sectional design of the contact method between the instrument and the canal wall is particularly important. Instruments with a non-square rhomboid or ordinary parallelogram cross-section design have a smaller two-point contact area with the root canal wall during operation, and have a sharp cutting edge, resulting in higher efficiency, reducing excessive friction and cutting on the dentin, and protecting the dentin wall of the canal.
[0034] Furthermore, the handle 100 is made of copper or stainless steel, and its outer cylindrical surface is electroplated. The operating part 200 is made of nickel-titanium alloy to enhance the rigidity of the root canal file and prevent bending and deformation during use, which could lead to reduced cutting efficiency, or even torsional deformation and breakage. The cross-sectional shape of the operating part 200 is formed by a continuous spiral trajectory. The root canal file is heat-treated at high temperature to achieve a gold finish. After heat treatment, the root canal file remains soft below 38°C, allowing for perfect preservation of the original morphology of the apex and middle and posterior segments of the root canal during preparation. This reduces surgical time, improves preparation accuracy, and adapts to different root canal morphologies and treatment needs, thus enhancing the flexibility of clinical application.
[0035] Furthermore, the tip of the root canal file features a non-cutting tip design, which provides better directional control, facilitates positioning, and reduces the risk of deviation.
[0036] As attached Figure 3 As shown, further, the cross-section of the first cutting edge 1 is rhomboid, with the four corners of the rhomboid denoted as A1, A2, A3, and A4. A1, A2, A3, and A4 are distributed counterclockwise on the rhomboid, with A1 and A3 correspondingly positioned and A2 and A4 correspondingly positioned. The vertices of A1 and A3 are both located on the working circumference T1 of the first cutting edge 1, while A2 and A4 are located inside the working circumference T1 of the first cutting edge 1. The cross-section of the first cutting edge 1 is designed to make the edges of A1 and A3 in the rhomboid sharp, enabling efficient cutting of dentin, reducing operation time, and improving cutting efficiency. Simultaneously, the high central stiffness of the rhomboid cross-section effectively resists bending deformation, making it suitable for cutting hard tissue and calcified root canals. This prevents bending deformation of the root canal file during cutting, which could lead to reduced cutting efficiency, or even torsional deformation and breakage.
[0037] Furthermore, the second cutting edge 2 has a rectangular cross-section, which can be used for four-point cutting inside the root canal. It has high flexibility and fatigue resistance, and can effectively resist bending deformation. It is suitable for cutting hard tissue and calcified root canals, preventing the root canal file from bending and deforming, which would reduce cutting efficiency, or even cause torsional deformation and breakage.
[0038] As attached Figure 3 As shown, furthermore, in the rhombus, A2 and A4 are both greater than 90°. This improves chip removal efficiency during use while better preserving dentin, thus increasing the root canal preparation rate.
[0039] As attached Figure 4As shown, further, the cross-section of the second cutting edge 2 is a conventional parallelogram, with its four corners denoted as B1, B2, B3, and B4. On this parallelogram, B1, B2, B3, and B4 are distributed counter-clockwise, with B1 and B3 corresponding to each other and B2 and B4 corresponding to each other. The vertices of B1 and B3 are both located on the working circumference T2 of the second cutting edge 2, while B2 and B4 are located inside the working circumference T2. This improves chip removal efficiency during use while better preserving dentin, thus increasing the root canal preparation rate.
[0040] Furthermore, the first cutting edge 1 has a square cross-section. The first cutting edge 1 with a square cross-section can be used for four-point cutting inside the root canal. It has high flexibility and fatigue resistance, can effectively resist bending deformation, and is suitable for cutting hard tissue and calcified root canals. It prevents the root canal file from bending and deforming, which would lead to reduced cutting efficiency, or even torsional deformation and breakage.
[0041] As attached Figure 4 As shown, further, in the ordinary parallelogram, B2 and B4 are both greater than 90°; and / or,
[0042] The lengths of adjacent sides of the ordinary parallelogram are not equal.
[0043] The standard parallelogram provides a larger chip removal space, which can effectively remove debris in the root canal, reduce the risk of blockage, and has good fatigue resistance. At the same time, the angle design of the standard parallelogram cross section reduces stress concentration, improves the fatigue resistance of the root canal file, and extends its service life.
[0044] Furthermore, in addition to the aforementioned scheme where the cross-section of the first cutting edge 1 is a rhombus for two-point cutting within the root canal and the cross-section of the second cutting edge 2 is a regular parallelogram for two-point cutting within the root canal, it is also possible to choose a scheme where the cross-section of the first cutting edge 1 is a rectangle or square for four-point cutting within the root canal and the cross-section of the second cutting edge 2 is a regular parallelogram or rhombus for two-point cutting within the root canal, or to choose a scheme where the cross-section of the first cutting edge 1 is a regular parallelogram or rhombus for two-point cutting within the root canal and the cross-section of the second cutting edge 2 is a rectangle or square for four-point cutting within the root canal, and the rhombus includes the square.
[0045] As attached Figure 1 To be continued Figure 2 As shown, further, the length L1 of the first cutting edge 1 is 1-10 mm; and / or,
[0046] The length L2 of the second cutting edge 2 is 4-20 mm; and / or,
[0047] The length L3 of the operating part 200 is 5-40 mm; and / or,
[0048] The diameter of the handle portion 100 is 1-10 mm; and / or,
[0049] The diameter of the operating part 200 gradually decreases in the direction away from the handle part 100.
[0050] The increasing size of the operating part 200 is defined according to the taper requirements at each point, which improves the doctor's ability to judge the length of the working part inserted into the patient's root canal during root canal self-treatment, improves the convenience of operation, ensures the cutting efficiency and stability of the tip, and improves chip removal ability and fatigue resistance.
[0051] Furthermore, the length L3 of the operating part 200 should be calculated from the tip of the first cutting edge 1 to the intersection of the two adjacent thread lines of the nearest second cutting edge 2.
[0052] Furthermore, preferably, the length L1 of the first cutting edge 1 is 4-6 mm; and / or,
[0053] The length L2 of the second cutting edge 2 is 10-12 mm; and / or,
[0054] The length L3 of the operating part 200 is 15.5-16.5 mm; and / or,
[0055] The diameter of the handle portion 100 is 2.32-2.35 mm.
[0056] Furthermore, the first cutting edge 1 is close to the tip of the operating part 200, and the second cutting edge 2 is close to the handle part 100. The overall diameter of the first cutting edge 1 is smaller than the overall diameter of the second cutting edge 2. This avoids the problem that if the first cutting edge 1 is located close to the handle part 100, the central stiffness of the middle and rear section of the first cutting edge 1 will gradually increase as the diameter increases, which may lead to over-preparation and the inability of a large amount of debris to be discharged from the bottom to the top during the preparation process, posing a risk of blockage. At the same time, it also avoids the problem that if the second cutting edge 2 is close to the tip of the operating part 200, the diameter will be too small and the central stiffness of the second cutting edge 2 will be low. When cutting hard tissue or calcified root canals, the root canal file is prone to bending and deformation, resulting in reduced cutting efficiency. During the rotational cutting process, it is prone to torsional deformation or even breakage.
[0057] As attached Figure 1 To be continued Figure 2 As shown, the operating part 200 further includes a smoothing part 3, which is disposed between the second blade part 2 and the handle part 100.
[0058] As attached Figure 1 To be continued Figure 2 As shown, further, the smooth portion 3 is provided with multiple engraved lines, the width of which is 0.1-1 mm; and / or,
[0059] The diameter of the smooth part 3 is 0.1-3 mm.
[0060] The etched lines are used to provide clinicians with real-time guidance on the depth of the root canal file within the root canal, preventing over-cutting and ensuring that the original morphology of the apex and middle and posterior segments of the root canal is perfectly preserved during the preparation process. This reduces surgical time, improves the accuracy of preparation, and adapts to different root canal morphologies and treatment needs, thereby enhancing the flexibility of clinical application.
[0061] Furthermore, preferably, the width of the scribe line is 0.2-0.3 mm; and / or,
[0062] The diameter of the smooth part 3 is 0.8-1.2 mm.
[0063] Furthermore, the etched lines are set to 2-4 lines and are laser-engraved. The color of the etched lines is defined according to the color of the operating part, and the color of the etched lines has a significant color difference from the operating part to highlight it. The width of the etched lines is 0.2-0.3mm. The etched lines are used to indicate to the clinician the depth position of the root canal file in the root canal in real time.
[0064] As attached Figure 1 To be continued Figure 2 As shown, the root canal file further includes a limiting part 4, which is disposed between the handle part 100 and the operating part 200. This facilitates the limiting installation of the root canal file when it is mounted on the preparation machine.
[0065] Furthermore, the diameter of the limiting part 4 is larger than the diameter of the handle part 100 and the operating part 200. The limiting part 4 is made of silicone rubber, and the color of the limiting part 4 is the same as the ink color of the handle part 100. The limiting part 4 is used in conjunction with the engraving lines on the smooth part 3 to facilitate operation by clinicians.
[0066] Furthermore, the smooth cylindrical surface of the handle 100 has an annular groove with a fixed position and size near the orifice. The groove is coated with ink, and the ink color is defined according to the nominal diameter of the tip of the root canal file, which makes it convenient for doctors to select the appropriate diameter based on the color. If the metal fatigue is caused by excessive torque or repeated use during operation, the root canal file will break at the annular groove, which makes it convenient for doctors to remove it in time, thereby preventing the operating part 200 from breaking in the root canal of the tooth.
[0067] Based on the aforementioned root canal file, this application embodiment also provides a root canal preparation machine, which adopts the technical solution described below, including the root canal file.
[0068] The root canal file combines the advantages of both ordinary parallelogram and rhomboid cross-sections. From its tip to the handle 100, the cross-sectional shape gradually transitions from a rhomboid to an ordinary parallelogram, maintaining two-point contact throughout the cutting process. This ensures more chip-holding space, guaranteeing both cutting efficiency and stability at the tip, while also improving chip removal capacity and fatigue resistance. The variable cross-section design of the root canal file can adapt to different root canal morphologies and treatment needs, increasing the flexibility of clinical application. It also avoids over-preparation during clinical operations, allowing the original morphology of the root canal apex and middle and posterior segments to be perfectly preserved during preparation, reducing surgical time and improving preparation accuracy. Furthermore, the smooth transition between the first cutting edge 1 and the second cutting edge 2, with a complete helix, reduces stress concentration caused by abrupt changes in cross-sectional shape, lowering the risk of instrument breakage.
[0069] Before use, sterilize the root canal files by disinfecting them with alcohol, high-temperature steaming, or other disinfectants to ensure sterility. During use, first use a triangular-shaped opening file to open the pulp chamber at the crown, exposing the pulp cavity. After opening the coronal pulp chamber, use the aforementioned root canal file to create a straight channel for the root canal. During this process, insert the file slowly into the pulp chamber, taking care to avoid damaging the canal walls. Then, use the aforementioned root canal file for transitional shaping of the root canal. Its unique cross-section allows it to adapt to various complex root canal environments, maximizing the success rate of root canal preparation. Finally, select a root canal file with the same variable cross-section but different specifications as the final shaping file to thoroughly remove debris generated during root canal preparation, creating a clean, complete, and smooth root canal channel, ensuring successful subsequent root canal filling.
[0070] Obviously, the embodiments described above are only some embodiments of this application, not all embodiments. The accompanying drawings show preferred embodiments of this application, but do not limit the patent scope of this application. This application can be implemented in many different forms; rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this application's specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the scope of patent protection of this application.
Claims
1. A root canal file, characterized in that, The root canal file includes a handle portion (100) and an operating portion (200). The operating portion (200) includes a first cutting edge (1) and a second cutting edge (2). The second cutting edge (2) is disposed between the handle portion (100) and the first cutting edge (1). The first cutting edge (1) and the second cutting edge (2) are respectively a common parallelogram, a rhombus, or a rectangle, and the first cutting edge (1) and the second cutting edge (2) have different shapes. At least one of the first cutting edge (1) and the second cutting edge (2) is a rhombus or a common parallelogram for two-point cutting in the root canal. The first cutting edge (1) and the second cutting edge (2) have a smooth transition.
2. The root canal file according to claim 1, characterized in that, The cross section of the first cutting edge (1) is a rhombus for two-point cutting inside the root canal. The four corners of the rhombus are denoted as A1, A2, A3 and A4 respectively. On the rhombus, A1, A2, A3 and A4 are distributed counterclockwise, and A1 and A3 are set in a corresponding manner as are A2 and A4. The vertices of A1 and A3 are both located on the working circumference T1 of the first cutting edge (1), and A2 and A4 are located inside the working circumference T1 of the first cutting edge (1).
3. The root canal file according to claim 2, characterized in that, The cross-section of the second blade (2) is rectangular.
4. The root canal file according to claim 1, characterized in that, The cross section of the second cutting edge (2) is a common parallelogram for two-point cutting inside the root canal. The four corners of the common parallelogram are denoted as B1, B2, B3 and B4 respectively. On the common parallelogram, B1, B2, B3 and B4 are distributed counterclockwise, and B1 and B3 are set in a corresponding manner as are B2 and B4. The vertices of B1 and B3 are both located on the working circumference T2 of the second cutting edge (2), and B2 and B4 are located inside the working circumference T2 of the second cutting edge (2).
5. The root canal file according to claim 4, characterized in that, The cross-section of the first cutting edge (1) is square.
6. The root canal file according to claim 1, characterized in that, The length L1 of the first cutting edge (1) is 1-10 mm; and / or, The length L2 of the second cutting edge (2) is 4-20 mm; and / or, The length L3 of the operating part (200) is 5-40 mm; and / or, The diameter of the handle portion (100) is 1-10 mm; and / or, The diameter of the operating part (200) gradually decreases in the direction away from the handle part (100).
7. The root canal file according to any one of claims 1-6, characterized in that, The operating part (200) further includes a smooth part (3), which is disposed between the second blade part (2) and the handle part (100).
8. The root canal file according to claim 7, characterized in that, The smooth portion (3) is provided with multiple engraved lines, the width of which is 0.1-1 mm; and / or, The diameter of the smooth part (3) is 0.1-3 mm.
9. The root canal file according to claim 8, characterized in that, The root canal file also includes a limiting part (4), which is disposed between the handle part (100) and the operating part (200).
10. A root canal preparation machine, characterized in that, Includes the root canal file as described in any one of claims 1-9.