In vitro orthodontic force testing tooling and force application method based on enamel crack characteristics

Abstract

The present invention provides an in vitro orthodontic force testing tooling and a force application method based on the characteristics of enamel cracks, which include: a mold body, which includes a bionic gingiva, experimental teeth and a connecting piece; a rotation fixing mechanism, which includes a rotating table, an assembly table and a clamping piece, the rotating table can rotate a preset angle, an installation groove is provided inside the assembly table, the mold body is arranged in the installation groove, and the clamping piece clamps the bionic gingiva; a traction mechanism, which is connected to a traction wire, and the traction wire can move or rotate linearly. The present invention applies different forces to the mold body through the interaction of the rotating mechanism and the traction mechanism to test the orthodontic force that can avoid tooth damage. It can not only adjust the tensile force, compressive force, lateral traction force, rotational traction force and torque force respectively, but also simulate the combined action of multiple forces, thereby making the test results highly match the actual orthodontic process. Furthermore, it has the advantages of rich functions, high simulation degree, accurate test results and wide application range.

Description

Technical Field

[0001] The present invention relates to the technical field of orthodontics, and specifically refers to an in vitro orthodontic force testing tooling and force application method based on the characteristics of enamel cracks. Background Art

[0002] In the field of modern dentistry, orthodontic treatment, as an important means of improving tooth alignment and occlusion, is widely used in the correction of various malocclusions. During the orthodontic treatment process, teeth need to withstand different types of mechanical forces, including but not limited to continuous light traction, intermittent elastic force, and complex torsional force, etc. The essence of orthodontic treatment is to apply appropriate mechanical forces to promote the slow movement of teeth in the alveolar bone so as to achieve the ideal alignment position. However, the application of such mechanical forces is not without risks, and one significant problem is the possible damage to the enamel.

[0003] Enamel, as the outermost hard tissue of teeth, plays an important role in protecting teeth. However, in orthodontic treatment, due to the relatively complex mechanical forces it bears, the enamel is prone to damage, and the most common manifestation is the formation and development of cracks. These cracks will not only affect the integrity of the enamel and destroy its protective barrier function for dentin and dental pulp, but may also further cause problems such as tooth sensitivity and dental caries. In severe cases, it may even affect the effect of orthodontic treatment and the oral health and quality of life of patients. In order to deeply understand the influence mechanism of orthodontic forces on enamel and then find effective methods to prevent and reduce enamel damage, it is necessary to use in vitro experimental models to simulate and study the effects of these forces on teeth. However, a key challenge currently faced in this field is that there is no in vitro force application device that can simulate common orthodontic forces.

[0004] Common orthodontic forces such as continuous light force, intermittent elastic force, and torsional force, etc., each have unique mechanical characteristics and action modes, and specific devices are required to accurately simulate them. Some existing simple in vitro force application devices have a single function and can only simulate limited types of forces, far from meeting the simulation requirements of the complex mechanical environment during orthodontic treatment. Not to mention an in vitro force application device with multiple force application functions that can simultaneously simulate multiple orthodontic forces and be flexibly adjusted, which is in a blank state in the market and research field. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the problem that it is difficult to simulate composite orthodontic forces in the prior art, and provide an in vitro orthodontic force testing tooling and force application method based on the characteristics of enamel cracks.

[0006] To solve the above technical problems, the present invention provides an in vitro orthodontic force testing tooling based on the characteristics of enamel cracks, which includes: a mold body, the mold body includes a bionic gum, experimental teeth and a connecting piece, the experimental teeth are fixed on the bionic gum, and the connecting piece is fixed on the buccal surface of the tooth crown of the experimental teeth; a rotation fixing mechanism, the rotation fixing mechanism includes a rotating table, an assembly table and a clamping piece, the rotating table can rotate a preset angle around a first rotation center line, the assembly table is arranged on the rotating table, and an installation groove is arranged inside it, the mold body is arranged in the installation groove, and the clamping piece penetrates through the assembly table to the installation groove to clamp the bionic gum; at least two traction mechanisms, at least two of the traction mechanisms are symmetrically arranged on opposite sides of the rotation fixing mechanism, and any traction mechanism is connected with a traction wire, one end of the traction wire is connected with the connecting piece, and the traction wire can move linearly or rotate around a second rotation center line under the action of an external force.

[0007] In an embodiment of the present invention, the in vitro orthodontic force testing tooling based on the characteristics of enamel cracks further includes a frame body, the rotation fixing mechanism is supported on the support surface of the frame body, wherein, a plurality of angle adjustment holes are arranged on the rotating table at circumferentially spaced intervals, and a plurality of positioning holes are arranged on the support surface at circumferentially spaced intervals, and the rotation fixing mechanism further includes a fixing piece, and the fixing piece can penetrate through the angle adjustment holes and the positioning holes to fix the angle of the rotating table.

[0008] In an embodiment of the present invention, the rotation fixing mechanism further includes a rotating shaft and at least one handle, the rotating shaft is arranged at the bottom of the rotating table and is connected to the support surface in a penetrating manner, and the handle is fixedly arranged on the side wall of the rotating table.

[0009] In an embodiment of the present invention, the rotation fixing mechanism includes two clamping pieces, the two clamping pieces respectively penetrate and connect the opposite sides of the assembly table, and can relatively approach / separate along their arrangement directions to clamp / release the bionic gum.

[0010] In an embodiment of the present invention, the traction mechanism includes a lifting rod and a traction column, a wire threading through hole is arranged on the traction column, the traction wire penetrates through the wire threading through hole, one end of the lifting rod is connected to the traction column, and the other end penetrates and connects to the rotating table, and can drive the traction column to move up and down along the thickness direction of the rotating table.

[0011] In an embodiment of the present invention, the traction mechanism further includes a connecting block, the bottom of the connecting block is connected to the lifting rod, the traction column slides through and is connected to the connecting block, and the traction column can move axially under the action of an external force.

[0012] In an embodiment of the present invention, the traction column includes a column body and a counterweight portion. The column body extends parallel to the tabletop of the rotating table. The wire threading through hole is provided at one end of the column body close to the rotating table, and the counterweight portion is provided at the end of the column body far from the rotating table. A counterweight hammer is suspended on the counterweight portion to drive the traction column to rotate around the second rotation center line.

[0013] In an embodiment of the present invention, the counterweight portion includes a hook bump and a wire winding groove. The wire winding groove is recessed from the edge of the counterweight portion towards its center, and the hook bump protrudes outward from the edge of the counterweight portion.

[0014] In an embodiment of the present invention, the mold body further includes a ligature wire. The ligature wire is wound around the connecting member, and the traction wire is wound and connected to the connecting member or the ligature wire.

[0015] In an embodiment of the present invention, the connecting member includes a bottom bracket and two fixing arms. The two fixing arms are arranged at intervals, and the ligature wire is wound around the two fixing arms.

[0016] In an embodiment of the present invention, the in vitro orthodontic force testing tool based on the enamel crack characteristics further includes an artificial saliva cap. The artificial saliva cap is filled in the installation groove and surrounds the experimental tooth, and artificial saliva is adsorbed inside it.

[0017] The present invention also provides an in vitro orthodontic force testing and force application method based on the enamel crack characteristics. Under the action of an external force, at least one of in vitro orthodontic tensile force, compressive force, lateral traction force, rotational traction force, and torque force is tested through the above-mentioned in vitro orthodontic force testing tool based on the enamel crack characteristics.

[0018] In an embodiment of the present invention, the steps for in vitro orthodontic tensile force testing are as follows: Fix the mold body to be tested in the installation groove, and make the connecting member face the traction mechanism. Then connect one end of the traction wire to the connecting member, and under the action of an external force drive, perform a local tensile force test on the experimental tooth by pulling the connecting member.

[0019] The steps for in vitro orthodontic compressive force testing are as follows: Fix the mold body to be tested in the installation groove, and make the connecting member face away from the traction mechanism. Then pass one end of the traction wire through the connecting member and sleeved on the experimental tooth, and under the action of an external force drive, perform a local compressive force test on the experimental tooth by squeezing it.

[0020] The steps for performing in vitro orthodontic lateral traction force testing are as follows: Fix the test mold in the installation groove, and set the orientation of the connecting piece at a preset angle α with respect to the traction direction of the traction mechanism. Then, connect one end of the traction wire to the connecting piece, and under the action of an external driving force, perform local lateral traction force testing on the test tooth by pulling the connecting piece, where 0° < α < 180°;

[0021] The steps for performing in vitro orthodontic rotational traction force testing are as follows: Fix the test mold in the installation groove. After passing the traction wire through the connecting piece, connect its two ends to two traction mechanisms respectively. Then, drive the rotating table to rotate around the first rotation center line to a preset angle, and under the action of an external driving force, perform local rotational traction force testing on the test tooth by twisting the connecting piece;

[0022] The steps for performing in vitro orthodontic torque force testing are as follows: Fix the test mold in the installation groove. After passing the traction wire through and connecting both sides of the connecting piece, connect it to at least one traction mechanism, and under the action of an external driving force, drive the traction wire to rotate and wind around the second rotation center line, so as to perform local torque force testing on the test tooth by twisting the connecting piece.

[0023] In an embodiment of the present invention, during the testing process, the test tooth is immersed in an artificial saliva environment.

[0024] In an embodiment of the present invention, when performing in vitro orthodontic torque force testing, fix the test mold in the installation groove. After passing the traction wire through and connecting both sides of the connecting piece, connect its two ends to the traction mechanisms respectively. Then, simultaneously drive the two ends of the traction wire to rotate and wind around the second rotation center line through an external acting force, and make the winding directions of the two ends of the traction wire opposite, so as to perform local torque force testing on the test tooth by twisting the connecting piece.

[0025] The above technical solution of the present invention has the following advantages compared with the prior art:

[0026] The in vitro orthodontic force testing tooling and force application method based on the enamel crack characteristics of the present invention apply different acting forces to the surface of the mold through the interaction of the rotating mechanism and the traction mechanism, thereby realizing the detection of the enamel crack characteristics of teeth under different external forces, and further testing the orthodontic force that can avoid tooth damage. During the testing process, it can not only adjust the tensile force, compressive force, lateral traction force, and rotational traction force respectively, but also highly simulate the combined action of multiple forces, so that the test results are highly matched with the actual orthodontic process. Compared with the current conventional orthodontic regulation technology, the present application has the advantages of rich functions, high simulation degree, flexible adjustment, accurate test results, and wide application range, and can meet the simulation requirements of complex mechanical environments during orthodontic treatment. Description of the Drawings

[0027] To make the content of the present invention easier to be clearly understood, the following further describes the present invention in detail according to specific embodiments of the present invention in conjunction with the accompanying drawings.

[0028] Figure 1 It is a schematic structural diagram of a frame body, a rotation fixing mechanism and a traction mechanism in an in vitro orthodontic force test device based on enamel crack characteristics in a preferred embodiment of the present invention;

[0029] Figure 2 is Figure 1 a top view;

[0030] Figure 3 is Figure 1 a schematic structural diagram of a mold body in the in vitro orthodontic force test device based on enamel crack characteristics shown;

[0031] Figure 4 is Figure 3 a schematic structural diagram of a connecting member in the mold body shown.

[0032] Description of reference numerals in the accompanying drawings of the specification: 100, frame body; 110, support surface; 200, rotation fixing mechanism; 210, rotating table; 211, angle adjustment hole; 220, rotating shaft; 230, fixing member; 240, handle; 250, assembly table; 251, installation groove; 260, clamping member; 300, traction mechanism; 310, lifting rod; 320, connecting block; 330, traction column; 331, column body; 332, wire passing through hole; 333, counterweight portion; 340, traction wire; 400, mold body; 410, bionic gum; 420, experimental tooth; 430, connecting member; 431, fixing arm; 432, bottom support; 500, counterweight hammer; 1001, first rotation center line; 1002, second rotation center line. Specific embodiments

[0033] The following further describes the present invention in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the embodiments cited do not limit the present invention.

[0034] Embodiment 1:

[0035] Referring to Figure 1 and Figure 2 shown, this embodiment provides an in vitro orthodontic force test tooling based on enamel crack characteristics, which is used to simulate the force condition of teeth during orthodontics, so as to test the damage degree of different orthodontic schemes to enamel through enamel crack characteristics, so as to achieve the protection of enamel during actual orthodontics.

[0036] Referring to Figure 3 and Figure 4As shown, in this embodiment, the phantom 400 is used to simulate teeth during the actual orthodontic process. It includes a bionic gum 410, experimental teeth 420, and a connecting member 430. The experimental teeth 420 are fixed on the bionic gum 410, and the connecting member 430 is fixed on the buccal surface of the crown of the experimental teeth 420. Further, in this embodiment, the experimental teeth 420 are fixed on the bionic gum 410, which can provide stable support and positioning, ensuring that the experimental teeth 420 remain in place during various experimental operations and mechanical loading, etc., without loosening or shifting easily, and guaranteeing the accuracy and repeatability of the experiment. The connecting member 430 is fixed on the buccal surface of the crown of the experimental teeth 420, facilitating the connection of the experimental teeth 420 with experimental equipment such as the traction wire 340, so as to accurately measure and control various mechanical parameters during the experiment.

[0037] Further, the phantom 400 further includes a ligature wire (not shown in the figure). The ligature wire can be wound around the connecting member 430, and the traction wire 340 is wound and connected to the connecting member 430 or the ligature wire. Specifically, the connecting member 430 includes a base 432 and two fixing arms 431. The two fixing arms 431 are spaced apart, and the ligature wire is wound around the two fixing arms 431, thereby enabling the traction wire 340 to act on the connecting member 430 in different connection ways.

[0038] Based on the structural arrangement of the above-mentioned phantom 400, in this embodiment, a rotary fixing mechanism 200 capable of installing and driving the phantom 400 to rotate, and a traction mechanism 300 capable of applying different forces to the phantom 400 through external forces are provided.

[0039] Among them, the rotary fixing mechanism 200 includes a rotating table 210, an assembly table 250, and a clamping member 260. The rotating table 210 can rotate a preset angle around the first rotation center line 1001. The assembly table 250 is arranged on the rotating table 210, and an installation groove 251 is provided inside it. The phantom 400 is arranged in the installation groove 251, and the clamping member 260 passes through the assembly table 250 into the installation groove 251 to clamp the bionic gum 410. Among them, for the convenience of rotation adjustment and improving the precise control of the rotation angle, the rotating table 210 is preferably a flat disc structure, and the first rotation center line 1001 extends along the thickness direction of the rotating table 210 and passes through the center of the rotating table 210.

[0040] Further, the in vitro orthodontic force test tool based on the characteristics of enamel cracks also includes a frame 100, and the rotating fixing mechanism 200 is supported on the supporting surface 110 of the frame 100. The frame 100 is used to support and install the rotating fixing mechanism 200, and at the same time, it can realize the positioning of the rotating table 210 through the fixing member 230. Specifically, the rotating table 210 is provided with a plurality of angle adjustment holes 211 arranged at intervals in the circumferential direction, and the supporting surface 110 is provided with a plurality of positioning holes arranged at intervals in the circumferential direction. The rotating fixing mechanism 200 also includes a fixing member 230, and the fixing member 230 can be penetrated with the angle adjustment hole 211 and the positioning hole to fix the angle of the rotating table 210. In this embodiment, the rotating table 210 is provided with a plurality of angle adjustment holes 211 with scale marks. When the operator twists the rotating table 210 to a preset angle, the fixing member 230 can be penetrated with the corresponding angle adjustment hole 211 and the positioning hole, thereby realizing the fixing of the rotation angle of the rotating table 210. In different implementations, the specific number and spacing angles of the angle adjustment holes 211 and the positioning holes can be adaptively adjusted according to actual usage requirements, and the present invention does not impose specific limitations on this.

[0041] Furthermore, the rotating fixing mechanism 200 in this embodiment also includes a rotating shaft 220 and two handles 240. The rotating shaft 220 is arranged at the bottom of the rotating table 210 and is connected to the supporting surface 110. The handle 240 is fixed to the side wall of the rotating table 210. During the process of driving the rotating table 210 to rotate, the operator can apply driving force to the rotating table 210 through the handle 240.

[0042] In this embodiment, the assembly platform 250 is arranged at the center of the rotating table 210, and it can rotate synchronously with the rotating table 210 around the first rotation center line 1001. It is used to provide an installation and connection space for the mold body 400 through the internal installation groove 251. Specifically, the installation groove 251 is arranged at the center of the assembly platform 250 and is recessed downward from its upper surface.

[0043] The clamping member 260 is used to clamp and fix the mold body 400 inside the installation groove 251. Specifically, in this embodiment, the rotating fixing mechanism 200 includes two clamping members 260, which are respectively connected to the two opposite sides of the assembly platform 250, and can be relatively close to / far away from each other along the arrangement direction to clamp / release the bionic gum 410. Further, the clamping member 260 in this embodiment is preferably a push screw, which can push and clamp the bionic gum 410 from the opposite sides. In different embodiments, the clamping member 260 can also be configured as other structures that can realize the fixed assembly of the bionic gum 410, and the present invention does not make specific restrictions on this.

[0044] In this embodiment, the traction mechanism 300 is connected to the connecting member 430, thereby facilitating the application of an external force. Specifically, this embodiment includes two traction mechanisms 300, and the two traction mechanisms 300 are symmetrically arranged on opposite sides of the rotary fixing mechanism 200. Any one of the traction mechanisms 300 is connected to a traction wire 340. One end of the traction wire 340 is connected to the connecting member 430, and the traction wire 340 can move linearly or rotate around the second rotation center line 1002 under the action of an external force.

[0045] Specifically, the traction mechanism 300 includes a lifting rod 310 and a traction column 330. A wire passing through hole 332 is provided on the traction column 330, and the traction wire 340 passes through the wire passing through hole 332. One end of the lifting rod 310 is connected to the traction column 330, and the other end is connected to the rotary table 210 in a penetrating manner and can drive the traction column 330 to move up and down along the thickness direction of the rotary table 210. Among them, the traction column 330 is used to connect and fix the traction wire 340, and the lifting rod 310 can adjust the height of the traction column 330 to realize the adjustment of the initial position of the traction wire 340. It should be noted that in the initial state, when measuring the tensile force or pressure, the traction wire 340 needs to extend horizontally, so as to ensure that the external force can be accurately transmitted to the surface of the experimental tooth 420.

[0046] Further, the traction mechanism 300 further includes a connecting block 320. The bottom of the connecting block 320 is connected to the lifting rod 310, and the traction column 330 is slidably connected to the connecting block 320 in a penetrating manner, and the traction column 330 can move along its axial direction under the action of an external force. Specifically, based on the above structure, when performing a tensile force test, one end of the traction wire 340 can be connected to the connecting member 430, and the other end can be connected to the traction column 330. Then, the traction column 330 is driven to move by an external force to realize the test of the local tensile force on the surface of the experimental tooth. Further, during the pulling process, the tensile force is detected in real time by a dynamometer, thereby improving the accuracy of the test results. In different embodiments, it is also possible to directly pull the connecting member 430 through the traction wire 340 by elements such as a spring dynamometer to simplify the test process. Correspondingly, the lateral traction force of the experimental tooth 420 can also be tested in the same way, and only the initial setting position of the connecting member 430 needs to be rotated.

[0047] When performing a pressure test, the middle part of the traction wire 340 needs to be sleeved on the surface of the experimental tooth 420, and then both ends of the traction wire 340 are passed through the connecting member 430 and fixed on the traction column 330. Next, the test of the pressure on the surface of the experimental tooth 420 can be realized by pulling with an external force in the same way.

[0048] Accordingly, when performing the rotational traction force test, the middle part of the traction wire 340 needs to pass through the connecting member 430, and at the same time, the two ends of the traction wire 340 are respectively connected to the two traction columns 330. After ensuring that the traction wire 340 is in a taut state, the rotating table 210 is adjusted. Thus, during the rotation process, the crack characteristics of the enamel of the experimental tooth 420 are observed to visually feedback the rotational traction force that the experimental tooth 420 can withstand.

[0049] Furthermore, in this embodiment, the traction column 330 includes a column body 331 and a counterweight portion 333. The column body 331 extends parallel to the tabletop of the rotating table 210. The wire passing through hole 332 is provided at one end of the column body 331 close to the rotating table 210. The counterweight portion 333 is provided at the end of the column body 331 away from the rotating table 210. A counterweight hammer 500 is suspended on the counterweight portion 333 to drive the traction column 330 to rotate around the second rotation center line 1002, wherein the second rotation center line 1002 coincides with the central axis of the traction column 330. Specifically, the counterweight portion 333 includes a hanging convex block and a wire winding groove. The wire winding groove is recessed from the edge of the counterweight portion 333 towards its center. The hanging convex block protrudes outwards from the edge of the counterweight portion 333. Based on the above structure, the test of the torque force of the experimental tooth 420 can be realized. Specifically, the middle part of the traction wire 340 passes through the two fixed arms 431 of the connecting member 430, and at the same time, the two ends of the traction wire 340 are respectively connected to the two traction columns 330. After ensuring that the traction wire 340 is in a taut state, the two traction columns 330 are driven to rotate synchronously around the second rotation center line by the release of the heavy hammer to realize the test of the torque force of the experimental tooth 420.

[0050] Furthermore, to improve the simulation degree, the in vitro orthodontic force test tooling based on the enamel crack characteristics in this embodiment further includes an artificial saliva cap. The artificial saliva cap is filled in the installation groove 251 and surrounds the experimental tooth 420, and artificial saliva is adsorbed inside it, thereby realizing a highly simulated process of the oral internal environment.

[0051] Embodiment Two:

[0052] This embodiment provides an in vitro orthodontic force test and force application method based on the enamel crack characteristics. Under the action of an external force, at least one of the in vitro orthodontic tensile force, compressive force, lateral traction force, rotational traction force, and torque force is tested through the in vitro orthodontic force test tooling based on the enamel crack characteristics described in Embodiment One. Specifically, in different usage scenarios, it can also perform tests of at least two different forces according to the actual usage requirements to simulate the combined force situation of the experimental tooth 420. The specific process is as follows:

[0053] Specifically, in this embodiment, the effect of orthodontic force on the occurrence and development of enamel cracks is studied by simulating the action of orthodontic force on enamel cracks. Orthodontic treatment is a continuous light force treatment, so in the industry, orthodontic forces are classified into mild, moderate, and heavy forces. This experimental device is designed to exclude the influence of other mechanical forces such as biting force and wear and study the influence of orthodontic force on the occurrence and development of enamel cracks. In this embodiment, local tensile tests are performed on the experimental tooth 420 under the action of heavy force: 3.5 N (calculated under the condition that a load of 350 g has a gravitational acceleration g of 10 N / kg), moderate force: 2.0 N, and mild force: 0.8 N.

[0054] The total sample size of the experiments in this application is 336 extracted teeth, with 28 teeth in each group, including 12 subgroups of a control group, a tensile force group (3.5 N, 2.0 N, and 0.8 N), a pressure group (3.5 N, 2.0 N, and 0.8 N), a lateral traction force group (3.5 N, 2.0 N, and 0.8 N), a 40° torque force group, and a 30° torsional force group.

[0055] Specifically, the extracted teeth selected in this application are all premolars extracted due to orthodontics in patients aged 12 - 30 years, and there are no defects in the buccal enamel of the teeth, no abnormal enamel development, no demineralization and caries on the buccal surface of the teeth. Before the test, experimental teeth will be excluded. The exclusion criteria include: teeth with structural abnormalities, those who have received dental disease treatment, those with a history of orthodontic treatment, those with a history of restorative treatment, those who have received chemical agent pretreatment, and those with enamel fractures caused by tooth extraction. Therefore, the consistency of individual differences of the experimental teeth can be ensured.

[0056] The process of obtaining the crack characteristics (quantity, length, and width) is specifically as follows: A stereomicroscope is used to observe and record the microscopic morphology of the tooth enamel surface before applying force. Then, a microscopic image measurement and analysis software is used to perform depth-of-field extension processing on the image to distinguish and display the enamel cracks, thereby obtaining a clear depth-of-field image. Under a 10x lens and a 50x lens, the measurement tools of the microscopic image measurement and analysis software are used to observe and record the length and width of the enamel cracks, and a measurement report is generated in micrometers. After applying force, the enamel cracks are evaluated again using the same method.

[0057] The steps for performing an in vitro orthodontic tensile test are as follows: The test mold 400 to be tested is fixed in the installation groove 251, and the connecting member 430 is arranged facing the traction mechanism 300. Then, one end of the traction wire 340 is connected to the connecting member 430, and under the action of an external driving force, the experimental tooth 420 is subjected to a local tensile test by pulling the connecting member 430.

[0058] The steps for performing in vitro orthodontic pressure testing are as follows: Fix the test mold 400 in the installation groove 251, and arrange the connecting member 430 in a direction away from the traction mechanism 300. Then, pass one end of the traction wire 340 through the connecting member 430 and sleeved on the experimental tooth 420, and perform local pressure testing by squeezing the experimental tooth 420 under the action of an external driving force;

[0059] The steps for performing in vitro orthodontic lateral traction testing are as follows: Fix the test mold 400 in the installation groove 251, and arrange the connecting member 430 at a preset angle α with the traction direction of the traction mechanism 300. Then, connect one end of the traction wire 340 to the connecting member 430, and perform local lateral traction testing on the experimental tooth 420 by pulling the connecting member 430 under the action of an external driving force, where 0° < α < 180°;

[0060] The steps for performing in vitro orthodontic rotational traction testing are as follows: Fix the test mold 400 in the installation groove 251. After passing the traction wire 340 through the connecting member 430, connect its two ends to two traction mechanisms 300 respectively. Then, drive the rotating table 210 to rotate around the first rotation center line 1001 to a preset angle, and perform local rotational traction testing on the experimental tooth 420 by twisting the connecting member 430 under the action of an external driving force;

[0061] The steps for performing in vitro orthodontic torque force testing are as follows: Fix the test mold 400 in the installation groove 251. After passing the traction wire 340 through and connecting both sides of the connecting member 430, connect it to at least one traction mechanism 300, and drive the traction wire 340 to rotate and wind around the second rotation center line 1002 under the action of an external driving force, so as to perform local torque force testing on the experimental tooth 420 by twisting the connecting member 430. Further, specifically in this embodiment, when performing in vitro orthodontic torque force testing, fix the test mold 400 in the installation groove 251. After passing the traction wire 340 through and connecting both sides of the connecting member 430, connect its two ends to the traction mechanism 300 respectively. Then, drive the two ends of the traction wire 340 to rotate and wind around the second rotation center line 1002 simultaneously through an external acting force, and make the winding directions of the two ends of the traction wire 340 opposite, so as to perform local torque force testing on the experimental tooth 420 by twisting the connecting member 430.

[0062] After obtaining the numerical values of the crack characteristics before and after each group of experiments, batch import them into the SPSS statistical software for analysis and calculation. Finally, obtain the P - value, and perform the above - mentioned statistical analysis based on the P - value. Use SPSS 27.0 statistical software for analysis, and describe it with the mean ± standard deviation (X ± S) or median (first quartile, third quartile).

[0063] When comparing whether there is a difference P before and after applying force, the Shapiro-Wilk test is used to evaluate whether the data conforms to a normal distribution. If the data is normally distributed, a Levene's test for equality of variances is further performed. If both conditions are met (normal distribution + equal variances), a paired samples t-test is used; otherwise, the Wilcoxon test is applied. In the statistical analysis of the above-mentioned instrument, 0.05 is used as the critical value to judge whether the difference is statistically significant. Specifically:

[0064] When P < 0.05, it indicates that there are obvious changes in the surface crack characteristics of the experimental teeth before and after the implementation. At this time, it is proved that the teeth are easily damaged under this tensile condition;

[0065] When P ≥ 0.05, it indicates that there are no obvious changes in the surface crack characteristics of the experimental teeth before and after the implementation. At this time, it is proved that the teeth are not easily damaged under this tensile condition.

[0066] The final measurement results show that:

[0067] The changes in the surface crack characteristics of the experimental teeth before and after the application of a 3.5N tensile force are as follows:

[0068]

[0069] Based on the data in the above table, after applying a 3.5N tensile force to the experimental teeth, the number, length, and width of the cracks are 0 (0, 1.00), 0 (0, 1947.92), and 0 (0, 6.06) respectively, and the P-values are 0.025, 0.043, and 0.043 respectively. The changes in the cracks before and after applying force are statistically significant. When comparing with the control group, the P-value is 0.114, and the difference is not statistically significant.

[0070] After applying a 3.5N tensile force to the experimental teeth initially without cracks, new cracks appeared in some samples, and the difference was statistically significant compared with before the experiment (P < 0.05), but there was no significant difference compared with the control group (P > 0.05). This indicates that a 3.5N tensile force may have a certain impact on enamel, but it is not significant enough to exceed the normal physiological change range.

[0071] The changes in the surface crack characteristics of the experimental teeth before and after the application of a 2.0N tensile force and a 0.8N tensile force are as follows:

[0072]

[0073] After applying a tensile force of 2.0 N, the number, length, and width of the cracks were 0 (0, 0.25), 0 (0, 187.60), and 0 (0, 1.35) respectively, and the changes before and after the experiment were not significant. After applying a tensile force of 0.8 N, the crack characteristics did not change and were still 0 (0, 0). In addition, there were no significant differences in the changes in the number, length, and width of the cracks between the 2.0 N and 0.8 N groups.

[0074] There were no obvious changes in the crack characteristics of the experimental teeth before and after the experiments with 2.0 N and 0.8 N, indicating that a tensile force not exceeding 2.0 N in the short term will not trigger or exacerbate the development of enamel cracks and has relatively high safety.

[0075] The changes in the surface crack characteristics of the experimental teeth before and after applying a pressure of 3.5 N were as follows:

[0076]

[0077] Based on the above experimental data, after applying a pressure of 3.5 N to the experimental teeth, the number, length, and width of the cracks were 0 (0, 1.00), 0 (0, 1572.56), and 0 (0, 7.58), and the P values were 0.059, 0.068, and 0.068 respectively.

[0078] It can be seen from this that applying a pressure of 3.5 N will not have an obvious impact on the surface cracks of the experimental teeth.

[0079] The changes in the surface crack characteristics of the experimental teeth before and after applying a pressure of 2.0 N and 0.8 N were as follows:

[0080]

[0081] After applying pressures of 2.0 N and 0.8 N, the number, length, and width of the cracks did not change, all being 0 (0, 0), and no new cracks were observed.

[0082] The changes in the surface crack characteristics of the experimental teeth before and after applying a lateral traction force of 3.5 N were as follows:

[0083]

[0084] Based on the data in the above table, after applying a lateral traction force of 3.5 N to the experimental teeth, the number, length, and width of the cracks increased from 0 (0, 0) to 0 (0, 1.00), 0 (0, 1087.63), and 0 (0, 8.60), and the Ps were 0.014, 0.027, and 0.027 respectively. Compared with the control group, the P value for the three crack changes was 0.056.

[0085] In this experiment, after applying a lateral traction force of 3.5 N for 1 month, obvious new cracks were observed to occur or the existing cracks to expand (P < 0.05). This indicates that a relatively large traction force may exceed the elastic limit of the teeth, causing further expansion of enamel cracks. Especially in teeth with pre-existing cracks, the generation and development of cracks are more obvious.

[0086] The changes in the surface crack characteristics of the experimental teeth before and after applying lateral traction forces of 2.0 N and 0.8 N are as follows:

[0087]

[0088] In the 2.0 N lateral traction force group, the number, length, and width of the cracks after the experiment were 0 (0, 0.25), 0 (0, 664.08), and 0 (0, 1.88) respectively, and the P value was greater than 0.05. After applying a lateral traction force of 0.8 N, no new cracks occurred.

[0089] The changes in the surface crack characteristics of the experimental teeth under a 30° rotational traction force are as follows:

[0090]

[0091] In this study, 0.018-inch nickel-titanium round wires with a relatively large size commonly used clinically were selected as experimental materials to study their effects on enamel surface cracks during the orthodontic correction of teeth with a 30° twist. The results showed that no obvious new cracks occurred and no aggravation of existing cracks was observed after applying the force. This phenomenon can be attributed to the unique high resilience and superelastic characteristics of nickel-titanium materials, which can provide continuous and gentle forces during orthodontic treatment, thus reducing potential damage to enamel.

[0092] Based on the data in the above table, after applying a 30° rotational traction force, the crack characteristics of the initially crack-free group showed basically no change before and after the experiment.

[0093] The changes in the surface crack characteristics of the experimental teeth under a 40° torque force are as follows:

[0094]

[0095] After applying a 40° torque force, the number, length, and width of the cracks were 0 (0, 1.00), 0 (0, 1093.83), and 0 (0, 9.80) respectively, and the corresponding P values were 0.014, 0.028, and 0.028 (P < 0.05). When comparing the crack changes before and after the experiment with the control group, P was 0.056, which was not statistically significant.

[0096] The experimental data showed that in the initial crack-free group, a torque force of 40° significantly induced the formation of new cracks, and there were significant differences in their quantity, length, and width compared with those before the experiment (P = 0.056 compared with the control group, approaching 0.05).

[0097] During each of the above tests, the experimental teeth 420 were immersed in an artificial saliva environment at room temperature to improve the simulation of the test environment.

[0098] In summary, for the in vitro orthodontic force testing tooling and force application method based on the enamel crack characteristics described in the present invention, different acting forces are applied to the surface of the mold 400 through the interaction of the rotating mechanism and the traction mechanism 300, thereby realizing the detection of the enamel crack characteristics of teeth under different external forces, and then testing the orthodontic force that can avoid tooth damage. During the testing process, it can not only adjust the tensile force, compressive force, lateral traction force, and rotational traction force separately, but also highly simulate the combined action of multiple forces, thus making the test results highly match the actual orthodontic process. Compared with the current conventional orthodontic regulation techniques, this application has the advantages of rich functions, high simulation degree, flexible adjustment, accurate test results, and wide application range, and can meet the simulation requirements of the complex mechanical environment during orthodontic treatment.

[0099] Obviously, the above embodiments are only examples clearly described and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. An in vitro orthodontic force testing tooling based on the characteristics of enamel cracks, characterized in that: Comprising: A phantom, the phantom includes a bionic gum, an experimental tooth and a connecting member. The experimental tooth is fixed on the bionic gum, and the connecting member is fixed on the buccal surface of the crown of the experimental tooth; A rotary fixing mechanism, the rotary fixing mechanism includes a rotary table, an assembly table and a clamping member. The rotary table can rotate a preset angle around a first rotation center line. The assembly table is arranged on the rotary table, and an installation groove is provided inside it. The phantom is arranged in the installation groove, and the clamping member penetrates through the assembly table to the installation groove to clamp the bionic gum; At least two traction mechanisms, at least two of the traction mechanisms are symmetrically arranged on opposite sides of the rotary fixing mechanism. Any of the traction mechanisms is connected to a traction wire. One end of the traction wire is connected to the connecting member, and the traction wire can move linearly or rotate around a second rotation center line under the action of an external force. The traction mechanism includes a lifting rod and a traction column. A wire passing through hole is provided on the traction column, and the traction wire passes through the wire passing through hole. One end of the lifting rod is connected to the traction column, and the other end is connected to the rotary table in a penetrating manner and can drive the traction column to move up and down along the thickness direction of the rotary table.

2. The in vitro orthodontic force testing tooling based on the enamel crack characteristics according to claim 1, wherein: The in vitro orthodontic force test tooling based on the enamel crack characteristics further includes a frame body. The rotary fixing mechanism is supported on the support surface of the frame body. Among them, a plurality of angle adjustment holes are arranged on the rotary table at circumferential intervals, and a plurality of positioning holes are arranged on the support surface at circumferential intervals. The rotary fixing mechanism further includes a fixing member, and the fixing member can pass through the angle adjustment holes and the positioning holes to fix the angle of the rotary table.

3. The in vitro orthodontic force testing tooling based on the enamel crack characteristics according to claim 2, wherein: The rotary fixing mechanism further includes a rotating shaft and at least one handle. The rotating shaft is arranged at the bottom of the rotary table and is connected to the support surface in a penetrating manner, and the handle is fixed on the side wall of the rotary table.

4. The in vitro orthodontic force testing tooling based on the enamel crack characteristics according to claim 1, characterized in that: The rotary fixing mechanism includes two clamping members. The two clamping members respectively penetrate through and are connected to opposite sides of the assembly table, and can relatively approach or move away along their arrangement directions to clamp or release the bionic gum.

5. The in vitro orthodontic force testing tooling based on the enamel crack characteristics according to claim 1, wherein: The traction mechanism further includes a connecting block. The bottom of the connecting block is connected to the lifting rod, and the traction column is slidably connected to the connecting block in a penetrating manner, and the traction column can move axially under the action of an external force.

6. The in vitro orthodontic force test tooling based on the enamel crack characteristics according to claim 1, characterized in that: The traction column includes a column body and a counterweight portion. The column body extends parallel to the table surface of the rotary table. The wire passing through hole is arranged at one end of the column body close to the rotary table, and the counterweight portion is arranged at one end of the column body far from the rotary table. A counterweight hammer is suspended on the counterweight portion to drive the traction column to rotate around the second rotation center line.

7. The in vitro orthodontic force testing tooling based on the enamel crack characteristics according to claim 6, characterized in that: The counterweight portion includes a hooking convex block and a wire winding groove. The wire winding groove is recessed from the edge of the counterweight portion towards its center, and the hooking convex block protrudes outwards from the edge of the counterweight portion.

8. The in vitro orthodontic force testing tooling based on the enamel crack characteristics according to claim 1, characterized in that: The phantom further includes a ligature wire. The ligature wire is wound around the connecting member, and the traction wire is wound and connected to the connecting member or the ligature wire.

9. The in vitro orthodontic force testing tooling based on the enamel crack characteristics according to claim 8, characterized in that: The connecting member includes a base tray and two fixing arms. The two fixing arms are arranged at intervals, and the ligature wire is wound around the two fixing arms.

10. The in vitro orthodontic force testing tooling based on the enamel crack characteristics according to claim 1, characterized in that: The in vitro orthodontic force test tooling based on the enamel crack characteristics further includes an artificial saliva cap, which is filled in the installation groove, surrounds the experimental tooth, and adsorbs artificial saliva inside.

11. An in vitro orthodontic force test and force application method based on enamel crack characteristics, characterized in that: Under the action of an external force, at least one of in vitro orthodontic tensile force, pressure, lateral traction force, rotational traction force, and torque force is tested by the in vitro orthodontic force test tooling based on the enamel crack characteristics according to any one of claims 1 to 10.

12. The in vitro orthodontic force application method based on the enamel crack characteristics according to claim 11, wherein: The steps for performing the in vitro orthodontic tensile force test are as follows: Fix the test mold in the installation groove, and make the connecting piece face the traction mechanism. Then connect one end of the traction wire to the connecting piece, and under the action of an external force drive, perform a local tensile force test on the experimental tooth by pulling the connecting piece. The steps for performing the in vitro orthodontic pressure test are as follows: Fix the test mold in the installation groove, and make the connecting piece face away from the traction mechanism. Then pass one end of the traction wire through the connecting piece and sleeved on the experimental tooth, and under the action of an external force drive, perform a local pressure test on the experimental tooth by squeezing the experimental tooth. The steps for performing the in vitro orthodontic lateral traction force test are as follows: Fix the test mold in the installation groove, and make the orientation of the connecting piece set at a preset angle α with the traction direction of the traction mechanism. Then connect one end of the traction wire to the connecting piece, and under the action of an external force drive, perform a local lateral traction force test on the experimental tooth by pulling the connecting piece, where 0° < α < 180°. The steps for performing the in vitro orthodontic rotational traction force test are as follows: Fix the test mold in the installation groove. After passing the traction wire through the connecting piece, connect its two ends to two traction mechanisms respectively. Then drive the rotating table to rotate around the first rotation center line to a preset angle, and under the action of an external force drive, perform a local rotational traction force test on the experimental tooth by twisting the connecting piece. The steps for performing the in vitro orthodontic torque force test are as follows: Fix the test mold in the installation groove. After passing the traction wire through and connecting both sides of the connecting piece, connect it to at least one traction mechanism, and under the action of an external force drive, drive the traction wire to rotate and wind around the second rotation center line, so as to perform a local torque force test on the experimental tooth by twisting the connecting piece.

13. The in vitro orthodontic force testing and force application method based on enamel crack characteristics according to claim 11, wherein: During the test, immerse the experimental tooth in an artificial saliva environment.

14. The in vitro orthodontic force testing and force application method based on enamel crack characteristics according to claim 11, characterized in that: When performing the in vitro orthodontic torque force test, fix the test mold in the installation groove. After passing the traction wire through and connecting both sides of the connecting piece, connect its two ends to the traction mechanisms respectively. Then, through an external force, simultaneously drive the two ends of the traction wire to rotate and wind around the second rotation center line respectively, and make the winding directions of the two ends of the traction wire opposite, so as to perform a local torque force test on the experimental tooth by twisting the connecting piece.

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