Bragg grating-based orthodontic force measurement method and device

Abstract

The application discloses a kind of orthodontic force measurement method and device based on Bragg grating, comprising the following steps: S1, force measuring orthodontic arch wire is installed on tooth, the force measuring orthodontic arch wire includes orthodontic arch wire and the optical fiber Bragg grating arranged on orthodontic arch wire;S2, connect optical fiber Bragg grating, optical fiber signal demodulator and host computer;S3, execute occlusion action, and host computer calculates the transverse force and / or longitudinal force of tooth according to Bragg grating wavelength shift amount.This application realizes the dynamic continuous measurement of orthodontic force transverse component and torque component, can provide more data support for correction process, assist doctor to make more accurate diagnosis and treatment scheme, solve the problem that traditional strain type and piezoelectric sensor are large in size and difficult to enter directly measure.

Description

Technical Field

[0001] This invention belongs to the field of orthodontic technology, specifically relating to a method and device for measuring orthodontic force based on Bragg grating. Background Technology

[0002] The basic principle of orthodontics is to slowly move teeth by applying external force to pull the alveolar bone. This is typically done by bonding orthodontic appliances to the teeth and ligating orthodontic wires to the appliances. The elasticity or rigidity of the wires generates tension and pressure, thereby promoting alveolar bone remodeling and tooth movement. During orthodontic treatment, the magnitude of the applied force significantly affects the speed of tooth movement and whether root resorption occurs. Excessive force, while accelerating tooth movement and the orthodontic process, may lead to external root resorption, resulting in blunted and shortened roots, impacting long-term dental health. Insufficient force may result in slow tooth movement, prolonging the orthodontic process, or even preventing the movement of individual teeth, affecting the patient's orthodontic cycle. Therefore, measuring the magnitude of the force applied to the teeth during orthodontic treatment under physiological conditions is extremely important.

[0003] Existing technologies typically rely on common strain gauge or piezoelectric force sensors. However, due to the relatively large size of these sensors, it's impossible to maintain proper oral closure while measuring force. Therefore, auxiliary devices are usually used to effectively transmit the force, enabling orthodontic force measurement outside the mouth. Thin-film force sensors, due to their ultra-thin size, are widely used in orthodontics, typically for measuring occlusal forces. However, lateral forces are more crucial in orthodontic treatment, and thin-film force sensors cannot measure forces in other directions. The treatment process heavily depends on the orthodontist's experience, often leading to unexpected movement, root resorption, and prolonged treatment periods or unsatisfactory results. Summary of the Invention

[0004] To address the above problems, this invention proposes a method and device for measuring orthodontic forces in teeth straightening based on a Bragg grating. The technical solution adopted by this invention to solve the above technical problems is as follows:

[0005] A method for measuring orthodontic forces in teeth correction based on Bragg gratings includes the following steps:

[0006] S1, Install the force-measuring orthodontic archwire on the teeth, the force-measuring orthodontic archwire includes an orthodontic archwire and a fiber Bragg grating disposed on the orthodontic archwire;

[0007] S2 connects the fiber Bragg grating and the force calculation component;

[0008] S3, Execute the biting action. The force calculation component calculates the orthodontic force on the teeth based on the strain of the force-measuring orthodontic archwire. The orthodontic force includes lateral force and / or longitudinal force. The strain of the force-measuring orthodontic archwire is obtained based on the wavelength offset of the Bragg grating.

[0009] The orthodontic archwire has a slot in the middle near the lip side, and the fiber Bragg grating is located in the slot.

[0010] Before step S3, the wavelength change of the fiber Bragg grating is monitored, and step S3 is executed only after the wavelength of the fiber Bragg grating has stabilized.

[0011] The orthodontic force also includes relative torque, calculated using the following formula:

[0012] M0 = (EI∈) / y;

[0013] In the formula, M0 represents the relative torque, I represents the moment of inertia of the orthodontic archwire, y represents the vertical distance from the center of the fiber Bragg grating to the center of the orthodontic archwire, ∈ represents the strain of the force-measuring orthodontic archwire, and E represents the elastic modulus of the orthodontic archwire.

[0014] The lateral force is F x The calculation formula is as follows:

[0015] F x =EA∈;

[0016] In the formula, A represents the cross-sectional area of ​​the orthodontic archwire, E represents the elastic modulus of the orthodontic archwire, and ∈ represents the strain of the force-measuring orthodontic archwire;

[0017] Longitudinal force is F y The calculation formula is as follows:

[0018]

[0019] In the formula, L represents the distance between two adjacent teeth, x0 represents the distance between the center of the fiber Bragg grating and the teeth on the fixed side, I represents the moment of inertia of the orthodontic archwire, and y represents the vertical distance from the center of the fiber Bragg grating to the center of the orthodontic archwire.

[0020] A force measurement device for orthodontic treatment based on a Bragg grating includes a force-measuring orthodontic archwire for orthodontic treatment and a force calculation component for calculating the transverse and / or longitudinal forces of the teeth based on the strain of the force-measuring orthodontic archwire; the force-measuring orthodontic archwire includes an orthodontic archwire, and a slot is provided on the side of the orthodontic archwire near the labial side, and a fiber Bragg grating is provided in the slot.

[0021] The formula for calculating the lateral force is:

[0022] Fx =EA∈;

[0023] In the formula, F x Let A represent the lateral force, E represent the cross-sectional area of ​​the orthodontic archwire, and ∈ represent the elastic modulus of the orthodontic archwire.

[0024] The formula for calculating longitudinal force is:

[0025]

[0026] In the formula, L represents the distance between two adjacent teeth, x0 represents the distance between the center of the fiber Bragg grating and the teeth on the fixed side, I represents the moment of inertia of the orthodontic archwire, and y represents the vertical distance from the center of the fiber Bragg grating to the center of the orthodontic archwire.

[0027] The beneficial effects of this invention are:

[0028] This application incorporates a fiber Bragg grating within the orthodontic archwire. Based on the wavelength offset of the fiber Bragg grating, the strain of the force-measuring orthodontic archwire, which reflects the force applied to the teeth, is calculated. This strain is then used to calculate the lateral force, longitudinal force, and relative torque of the teeth during orthodontic treatment. This enables dynamic and continuous measurement of the lateral force, longitudinal force, and torque components of the orthodontic force, providing more data support for the correction process and assisting doctors in making more accurate treatment plans. It also solves the problems of traditional strain gauge and piezoelectric sensors being large and difficult to measure directly through the incision. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the process of the present invention.

[0031] Figure 2 This is a cross-sectional view of the force-measuring orthodontic archwire of the present invention.

[0032] Figure 3 This is a schematic diagram of the forces acting on a lateral force.

[0033] Figure 4 This is a schematic diagram of the forces acting on the bending moment.

[0034] Figure 5 This is a schematic diagram of the longitudinal force.

[0035] 1 is a force-measuring orthodontic archwire, 11 is an orthodontic archwire, 12 is a fiber Bragg grating, 2 is a fiber optic signal demodulator, 3 is a host computer, 4 is a tooth, and 5 is an orthodontic bracket. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1: A method for measuring orthodontic forces in teeth correction based on Bragg gratings, comprising the following steps:

[0038] S1, the force-measuring orthodontic archwire 1 is installed on the tooth 4, the force-measuring orthodontic archwire 1 includes an orthodontic archwire 11 and a fiber Bragg grating 12 disposed on the orthodontic archwire 11;

[0039] When fabricating a force-measuring orthodontic archwire, a fiber Bragg grating of the corresponding length can be fabricated first according to the measurement requirements. The fabricated fiber Bragg grating is then installed in a slot within the orthodontic archwire. Preferably, the slot is located in the middle of the orthodontic archwire near the labial side. When installing the force-measuring orthodontic archwire, the dentist can fix it to the tooth surface using orthodontic brackets 5. Preferably, the force-measuring orthodontic archwire is positioned in the middle of the orthodontic bracket to prevent the grating from being stuck inside the bracket and affecting measurement accuracy.

[0040] S2, as Figure 1 As shown, the fiber Bragg grating 12, the fiber optic signal demodulator 2, and the host computer 3 are connected.

[0041] The fiber optic signal demodulator is used to receive the reflected light from the fiber Bragg grating and convert the optical signal into an electrical signal. The host computer is used to detect changes in the spectral signal based on the converted electrical signal, and then analyze the force on the tooth based on the changes in the spectrum. The two process the signal separately and together form the force calculation component.

[0042] S3, execute the biting action, the host computer 3 calculates the orthodontic force of the tooth 4 according to the strain of the force-measuring orthodontic archwire 1, the strain of the force-measuring orthodontic archwire 1 is obtained based on the wavelength offset of the fiber Bragg grating 12.

[0043] The patient begins to bite according to the doctor's instructions. During the biting process, the displacement of the teeth causes a slight elastic deformation of the force-measuring orthodontic archwire, which in turn causes a shift in the wavelength of the Bragg grating. The fiber optic demodulator demodulates the wavelength signal and returns it to the host computer. The host computer calculates the force on the force-measuring orthodontic archwire, that is, the force between adjacent teeth, based on the changed wavelength.

[0044] Preferably, since the wavelength shift of the fiber Bragg grating is greatly affected by temperature, the wavelength change of the Bragg grating needs to be monitored before occlusion begins, until the signal stabilizes, that is, when the temperature of the force-measuring orthodontic archwire is consistent with the temperature inside the oral cavity, before the force calculation can begin.

[0045] The calculation relationship between the Bragg grating wavelength offset and the strain of the force-measuring orthodontic archwire is as follows:

[0046] Δλ=λ B (1-P e )∈; (1)

[0047] In the formula, λ B P represents the initial wavelength of the Bragg grating, preferably the initial wavelength of the Bragg grating when the temperature of the force-measuring orthodontic archwire is the same as the intraoral temperature. e denoted by the photoelastic coefficient, which is a constant, ∈ represents the strain of the force-measuring orthodontic archwire, and Δλ represents the wavelength shift of the Bragg grating caused by the deformation of the force-measuring orthodontic archwire.

[0048] The orthodontic force includes lateral force and / or longitudinal force, and may also include relative torque. Since orthodontic force is complex, this application only analyzes these three types of force. Specifically, the strain of the force-measuring orthodontic archwire can be calculated according to formula (1), and then the doctor judges the tooth movement pattern near the measurement point to determine the main relative movement pattern of the teeth. The relative movement pattern includes the following three types:

[0049] The first type is lateral stretching, such as Figure 3 As shown, this refers to the movement of teeth along the tangential direction of the dental arch, which manifests as the distance between two adjacent teeth increasing along the direction of the orthodontic archwire, meaning that the lateral force is the main force on the teeth.

[0050] The lateral force of the tooth is F x The calculation formula is as follows:

[0051] F x =EA∈; (2)

[0052] In the formula, E represents the elastic modulus of the orthodontic archwire, and A represents the cross-sectional area of ​​the orthodontic archwire. Since the modulus of the optical fiber differs greatly from that of the orthodontic wire, this application mainly uses the cross-sectional area of ​​the slotted orthodontic archwire.

[0053] The second type is relative rotation, such as Figure 4 As shown, this is manifested as two adjacent teeth rotating around their respective points fixed to the orthodontic archwire, meaning that the relative torque, or bending moment, is the main force on the teeth.

[0054] The relative torque is represented by M0, and its calculation formula is as follows:

[0055] M0 = (EI∈) / y; (3)

[0056] In the formula, I represents the moment of inertia of the orthodontic archwire, and y represents the vertical distance from the center of the fiber Bragg grating to the center of the orthodontic archwire.

[0057] The third type is the staggered movement of front and back, such as Figure 5 As shown, this manifests as teeth moving towards the labial or lingual side, meaning that longitudinal force is the main force on the teeth;

[0058] Longitudinal force is F y The calculation formula is as follows:

[0059]

[0060] In the formula, L represents the distance between two adjacent teeth, and x0 represents the distance between the center of the fiber Bragg grating and the tooth on the fixed side.

[0061] The force on the teeth during orthodontic treatment can be obtained through formulas (2), (3) and (4). In specific measurements, doctors can select appropriate formulas to calculate orthodontic force based on the relative movement pattern of the patient's teeth. This solves the problem that the force on the teeth cannot be accurately assessed in existing technologies, provides reference data for orthodontists, and effectively avoids orthodontic failure.

[0062] Example 2: A dental orthodontic force measurement device based on Bragg grating, such as Figure 1 and Figure 2 As shown, the device includes a force-measuring orthodontic archwire 1 for correcting tooth 4 and a force calculation component for calculating the transverse and / or longitudinal forces of tooth 4 based on the strain of the force-measuring orthodontic archwire 1. The force-measuring orthodontic archwire 1 includes an orthodontic archwire 11, with a slot on the labial side of the archwire 11. A fiber Bragg grating 12 is disposed in the slot, and the force-measuring orthodontic archwire 1 is fixed to the surface of tooth 4 by an orthodontic bracket 5. Specifically, the fiber Bragg grating 12 can be fixed by adhesive or snap-fit, so that the orthodontic archwire 11 and the fiber Bragg grating 12 become a whole, so as to better fix the force-measuring orthodontic archwire 1 in the orthodontic bracket 5.

[0063] The force calculation component includes a light signal demodulator 2 for demodulating the light signal reflected by the force-measuring orthodontic archwire 1, and a host computer 3 for calculating the lateral force and / or longitudinal force of tooth 4 based on the strain of the force-measuring orthodontic archwire 1 after tooth 4 occlusion. The output of the light signal demodulator 2 is connected to the input of the host computer 3. The host computer can also calculate the relative torque of the tooth based on the strain. The calculation formulas for the strain of the force-measuring orthodontic archwire 1, the lateral force, the longitudinal force, and the relative torque of tooth 4 are given in Example 1 and will not be repeated in this example.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for measuring orthodontic forces in teeth correction based on Bragg gratings, characterized in that, Includes the following steps: S1, the force-measuring orthodontic archwire (1) is installed on the tooth (4), the force-measuring orthodontic archwire (1) includes an orthodontic archwire (11) and a fiber Bragg grating (12) disposed on the orthodontic archwire (11). S2 connects the fiber Bragg grating (12) and the force calculation component; S3, perform the biting action, the force calculation component calculates the orthodontic force of the tooth (4) according to the strain of the force-measuring orthodontic archwire (1), the orthodontic force including lateral force and / or longitudinal force; the strain of the force-measuring orthodontic archwire (1) is obtained based on the Bragg grating wavelength offset; The orthodontic force also includes relative torque, calculated using the following formula: ； In the formula, Represents relative torque. The moment of inertia of the cross section of the orthodontic archwire (11) is represented. This represents the vertical distance from the center of the fiber Bragg grating (12) to the center of the orthodontic archwire (11). This represents the strain of the force-measuring orthodontic archwire (1). This represents the elastic modulus of the orthodontic archwire (11); Longitudinal force adopted The calculation formula is as follows: ； In the formula, It indicates the distance between two adjacent teeth. This indicates the distance between the center of the fiber Bragg grating and the teeth on the fixed side. The moment of inertia of the cross section of the orthodontic archwire (11) is represented. This represents the vertical distance from the center of the fiber Bragg grating (12) to the center of the orthodontic archwire (11).

2. The method for measuring orthodontic forces in teeth correction based on Bragg grating according to claim 1, characterized in that, The orthodontic archwire (11) has a slot in the middle near the lip side, and the fiber Bragg grating (12) is located in the slot.

3. The method for measuring orthodontic forces in teeth correction based on Bragg grating according to claim 1, characterized in that, Before step S3, the wavelength change of the fiber Bragg grating (12) is monitored, and step S3 is executed after the wavelength of the fiber Bragg grating (12) stabilizes.

4. The method for measuring orthodontic force based on Bragg grating according to claim 1, characterized in that, The lateral force adopts The calculation formula is as follows: ； In the formula, This represents the cross-sectional area of ​​the orthodontic archwire (11).

5. A dental orthodontic force measurement device based on a Bragg grating, characterized in that, It includes a force-measuring orthodontic archwire (1) for orthodontic treatment of teeth (4) and a force calculation component for calculating the transverse and / or longitudinal forces of teeth (4) based on the strain of the force-measuring orthodontic archwire (1); the force-measuring orthodontic archwire (1) includes an orthodontic archwire (11), and a slot is provided on the side of the orthodontic archwire (11) near the labial side, and a fiber Bragg grating (12) is provided in the slot. Longitudinal force adopted The calculation formula is as follows: ； In the formula, It indicates the distance between two adjacent teeth. This indicates the distance between the center of the fiber Bragg grating and the teeth on the fixed side. The moment of inertia of the cross section of the orthodontic archwire (11) is represented. This represents the vertical distance from the center of the fiber Bragg grating (12) to the center of the orthodontic archwire (11). This represents the elastic modulus of the orthodontic archwire (11). The strain of the force-measuring orthodontic archwire (1) is represented.

6. The orthodontic force measurement device based on Bragg grating according to claim 5, characterized in that, The formula for calculating the lateral force is: ； In the formula, Indicates lateral force. This represents the cross-sectional area of ​​the orthodontic archwire (11).

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