Device and method for measuring tooth occlusal force through fusion of vibrating wire and strain

Abstract

The invention discloses a vibrating wire fusion strain tooth occlusal force measuring device and method, and belongs to the technical field of oral biomechanical testing. The device adopts a split structure and comprises a cover body, a shell, a measuring main body and a handle main body, the cover body and the shell are connected to form a shell and serve as a tooth stress surface; the measuring main body is accommodated in the shell, a first convex part of the measuring main body is provided with a string clamping device for fixing and tensioning the vibrating string, and a second convex part is provided with a strain gauge; the handle body is provided with a display module and a battery. Based on a vibrating wire sensing principle, a force value is obtained by measuring a vibrating wire tension change and an inherent frequency change caused by a bite force, compensation is carried out in combination with a strain gauge signal, and a result is directly displayed on a display module after calculation by a built-in circuit. The device has the advantages of strong anti-interference capability, high measurement precision, integration, convenience in cleaning and disinfection and simplicity and convenience in operation, and is suitable for clinical oral diagnosis and biomechanical research.

Description

Technical Field

[0001] This invention relates to the field of oral biomechanical testing technology, specifically to a device and method for measuring tooth occlusal force using vibrating wire fusion strain. The device and method of this invention can be used for tooth occlusal force measurement in clinical oral diagnosis, laboratory occlusal force testing, and oral biomechanical research. Background Technology

[0002] Occlusal force is an important indicator for evaluating oral masticatory function and dental health. In particular, the occlusal force of a single tooth or a pair of teeth can objectively reflect the degree of damage to diseased teeth and has important reference value for the diagnosis of various periodontal diseases. Because the perception of pain and occlusal discomfort is regional, it is necessary to measure the occlusal force of each pair of teeth separately in clinical practice to determine which pair of teeth has functional abnormalities and to provide quantitative basis for the design and installation of prosthetic restorations.

[0003] However, traditional tooth occlusal force sensing technology has many shortcomings. First, strain output sensors are greatly affected by temperature, electromagnetic interference, and changes in wiring, easily causing zero-point drift and making it difficult to guarantee repeatability and long-term stability. Second, most sensing elements are sealed integrated structures, lacking tension or sensitivity adjustment methods, making it difficult to eliminate assembly and aging errors, affecting calibration consistency. Third, most devices require external data acquisition modules for amplification and reading, lacking integrated functionality, making the system complex to use and inconvenient to carry. Finally, existing devices are mostly expensive, with high maintenance costs. For example, Chinese invention patent CN 110638475 A discloses a high-precision occlusal force measuring instrument and method based on single-chip microcomputer control, mainly using a replaceable piezoelectric thin film sensor.

[0004] Therefore, there is an urgent need in this field for a tooth occlusal force measurement solution that can overcome the above-mentioned defects, has high stability, high precision, is integrated and easy to maintain. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of large signal drift, non-adjustable structure, reliance on external equipment, inconvenience of use, and high maintenance costs of existing tooth occlusal force measurement devices, and to provide a vibrating wire fused strain tooth occlusal force measurement device and method. The device integrates data acquisition, processing, and display functions in its structure, and can complete the entire measurement process without external electronic equipment, significantly improving the system's portability and clinical applicability.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a tooth occlusal force measuring device based on vibrating wire fusion strain, comprising a cover, a measuring body, a housing, and a handle body;

[0008] The cover and the shell are connected to each other to form a split shell, and the cover and the shell respectively form force-bearing surfaces for contact with the upper and lower teeth;

[0009] The measuring body is placed in an accommodating space formed by the cover and the shell. The measuring body is equipped with a vibrating wire and a strain gauge. The vibrating wire is configured to change its tension under prestressed tension as the measuring body is deformed by the biting force. The strain gauge is configured to sense the strain of the measuring body.

[0010] The handle body is connected to the housing, and a display module is provided on the handle body;

[0011] The device further includes a data acquisition and processing module, which is configured to calculate the bite force value based on the vibration signal of the vibrating wire and the output voltage signal of the strain gauge, and output the value to the display module for display.

[0012] Furthermore, the measuring body includes a first protrusion and a second protrusion. The first protrusion has a string clamp inside, and the vibrating string is fixed or adjusted by the string clamp. The strain gauge is disposed on the second protrusion.

[0013] Furthermore, the first protrusion has a first through hole in the horizontal direction, and the string clamp is disposed in the first through hole; the string clamp has a string clamping groove for fixing the vibrating string and a string adjustment hole for adjusting the tension of the vibrating string.

[0014] Furthermore, the top of the first protrusion is provided with a first fixing hole that communicates with the first through hole, and the first screw passes through the first fixing hole and abuts against the string clamp to fix the string clamp.

[0015] Furthermore, the second protrusion has a second through hole in the horizontal direction, and the strain gauges are symmetrically arranged in the second through hole and connected by a full-bridge circuit. The top of the second protrusion has a second fixing hole, and a second screw passes through the second fixing hole and abuts against the bottom of the second protrusion to stabilize it. Those skilled in the art can adjust the number, layout, and circuit connection method between the strain gauges according to actual needs.

[0016] Furthermore, the cover and the shell are respectively provided with a first groove and a second groove, through which the measuring body is accommodated; the cover and the measuring body, as well as the cover and the shell, are detachably connected, which facilitates maintenance and cleaning.

[0017] Furthermore, a first hole is provided on one side of the measuring body, and a second hole is provided on one side of the housing. The measuring body and the housing are connected by a positioning pin, which passes through the corresponding first and second holes on the measuring body and the housing and is fixed by screws. The handle body is connected to the housing by the positioning pin.

[0018] Furthermore, the cover is made of biocompatible medical-grade resin and has an annular sealing ring inside. The annular sealing ring is placed on the outer diameter of the mounting part to prevent moisture and saliva from entering.

[0019] Furthermore, the strain gauge is made of high-precision metal foil material and is connected to the internal data acquisition circuit to compensate or calibrate the vibrating wire frequency measurement, thereby improving the measurement accuracy.

[0020] Furthermore, the vibrating string is a high-strength metal steel string with a fixed length and material density, so that the natural frequency of the vibrating string has a definite relationship with its tension. When the measuring body is subjected to slight deformation due to the biting action of the teeth, the tension of the vibrating string changes, resulting in a change in the natural frequency, which is collected by the vibration sensor to improve the sensitivity and stability of the biting force measurement.

[0021] Furthermore, to ensure stable fixation of the string clamp and the vibrating string, the string clamp can be made of an elastic material.

[0022] Furthermore, the data acquisition and processing module includes:

[0023] A vibration sensor is installed on the measuring body to collect the vibration signal of the vibrating string;

[0024] The frequency counting unit is used to obtain the vibration frequency of the vibrating string based on the signal from the vibration sensor;

[0025] A bridge-type measurement and preamplification unit is used to amplify and convert the voltage signal output by the strain gauge into an analog-to-digital signal.

[0026] The microcontroller unit is used to calculate the bite force value based on the vibration frequency and the amplified strain signal, according to a preset calibration relationship.

[0027] Furthermore, the expression for calculating the bite force is as follows:

[0028]

[0029] in, This is the real-time fundamental frequency of the vibrating string; The effective length of the vibrating string; The linear density of the vibrating string; The initial pretension of the vibrating string; The axial stiffness of the vibrating string; To measure the equivalent compliance of the main body in the direction of the string clamp connection; The output voltage of the strain gauge bridge after amplification; For instrument-grade differential amplifier gain; These are conversion factors; The strain gauge sensitivity coefficient; Set the voltage for the bridge circuit; The values ​​are used to calibrate the position of the strain gauge. To integrate weights, .

[0030] Furthermore, a vibration sensor is provided inside or below the first protrusion to collect the vibration signal of the vibrating string; the strain gauges are connected by a full-bridge circuit; the vibration sensor, strain gauges and display module are electrically connected through internal circuits; the data acquisition and processing module is used to acquire and calculate the frequency of the vibrating string and the output of the strain gauge bridge, and output the calculated biting force value to the display module.

[0031] Furthermore, a vibration sensor is attached to the first protrusion near the vibrating string to pick up vibration acceleration or bending charge signals. An electromagnetic vibration pickup coil is preferred.

[0032] Furthermore, the frequency counting unit is used to shape the signal output from the vibration sensor and input it into the counting channel of the microcontroller timer to obtain the vibrating string frequency; the bridge measurement and preamplification unit includes an instrument-grade differential amplifier and a high-resolution Δ-Σ analog-to-digital converter to amplify and digitize the full-bridge strain signal; the microcontroller unit is used to run the calibration curve and compensation algorithm and drive the display module. Preferably, instrumentation amplifiers such as INA333 / AD8421 / AD8422 and bridge ADCs such as ADS1232 are used.

[0033] Secondly, the present invention provides a method for measuring tooth occlusal force using a vibrating wire fusion strain method, employing the aforementioned vibrating wire fusion strain tooth occlusal force measuring device, comprising the following steps:

[0034] The measuring device is placed between the upper and lower teeth to be measured;

[0035] Applying a biting force, the tooth biting force signal is acquired by measuring the tension and frequency changes of the vibrating wire caused by the deformation of the measuring body, and the strain gauge deformation signal; during the biting process, the tooth biting force signal is acquired by measuring the frequency change of the vibrating wire and the deformation change of the strain gauge inside the measuring body. The vibration of the vibrating wire is acquired by a vibration pickup sensor, and the strain of the strain gauge is used to assist in obtaining the biting force signal and is acquired by the internal circuit.

[0036] The bite force value is calculated based on the collected vibration frequency signal and strain signal;

[0037] The bite force value is displayed via a display module.

[0038] Furthermore, before the instrument is put into use, the vibrating wire and strain gauge are initially calibrated and zero-point calibrated, including adjusting the wire clamp to set the initial tension of the vibrating wire, adjusting the tightness of the mounting plate to set the initial strain of the strain gauge, and recording the vibration frequency of the vibrating wire under no-load conditions. and strain gauge output voltage As a reference value; during the calibration measurement process, the real-time frequency is acquired synchronously. With output voltage The two values ​​are then paired and calculated with the reference value, i.e., the frequency channel is processed using the difference squared (in... (Calculate the frequency difference), the strain channel uses differential processing (to...) Calculate the output voltage difference. Based on the difference, adjust the initial tension of the vibrating string and the initial strain of the strain gauge until the difference meets the error requirements.

[0039] This device, while maintaining overall structural rigidity and clinical operability, employs a clamping structure to fix a tensioned vibrating string. The biting force causes a slight deformation of the measuring body, resulting in a change in the string tension and thus a change in its natural frequency. It can acquire, process, and display biting force in real time without the need for external equipment. Furthermore, the device has low manufacturing cost, is easy to disassemble, and requires minimal repair and remanufacturing costs. Compared to existing technologies, this invention offers advantages such as stable frequency signal output, strong anti-interference capability, adjustable and reusable structure, and high degree of integration, making it particularly suitable for rapid clinical deployment, repeated use, and biting force measurement scenarios requiring high accuracy and reliability.

[0040] The present invention has the following beneficial effects:

[0041] (1) High measurement accuracy and strong anti-interference ability: The present invention uses the vibrating wire frequency as the sensing signal. The frequency signal is almost unaffected by temperature, wire resistance and electromagnetic noise during transmission and measurement, which fundamentally overcomes the shortcomings of the analog signal of traditional strain gauge sensors that are prone to drift, and ensures the long-term stability and high accuracy of the measurement. In addition, the strain gauge compensates or calibrates the vibrating wire frequency measurement, further improving the measurement accuracy.

[0042] (2) Adjustable structure and convenient maintenance: Through the unique design of the string clamp and tuning hole, the initial tension of the vibrating string can be precisely set and adjusted, effectively compensating for assembly errors and relaxation after long-term use, ensuring the stability of sensor sensitivity and the consistency of calibration. The split shell design makes the core measuring components easy to disassemble, clean and repair, reducing maintenance costs.

[0043] (3) High integration and easy operation: This invention integrates force sensing, signal acquisition, data processing and result display into a handheld device, realizing a "bite and read" measurement mode. No external complex equipment is required, which greatly improves the convenience and efficiency of clinical operation and makes it easier for doctors to quickly obtain diagnostic information.

[0044] (4) Better patient experience and more accurate measurements: The parts of the device that come into contact with the oral cavity are made of biocompatible materials and can be disinfected, meeting hygiene requirements. The main handle is placed outside the mouth, making it comfortable to hold and reducing patient discomfort. The sensor components are designed to be thin and compact, with minimal interference to normal biting posture, thus making the measurement results more accurately reflect the patient's natural biting force. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0046] Figure 2 This is a schematic diagram of the cover structure;

[0047] Figure 3 This is a schematic diagram of the shell structure;

[0048] Figure 4 This is a schematic diagram of the main structure for measurement;

[0049] Figure 5 Schematic diagram of the cross-section of the main body for measurement

[0050] Figure 6 This is a schematic diagram of the main structure of the handle;

[0051] Figure 7 This is a schematic diagram of the string clamp structure;

[0052] Figure 8 Schematic diagram of mounting plate and strain gauge structure

[0053] Figure 9 Connection diagram of the housing, measuring body, and handle body;

[0054] Figure 10 This is a three-dimensional structural assembly drawing of the present invention;

[0055] In the picture:

[0056] 1. Cover body; 11. Annular sealing ring; 12. First fixing groove; 13. First groove body; 14. Mounting part; 15. Second fixing groove;

[0057] 2. Measuring body, 21. First protrusion, 22. Second protrusion, 23. First fixing piece, 24. Mounting plate, 25. Vibrating string, 26. First screw, 27. Tenth fixing hole, 28. Second screw, 29. Strain gauge, 210. Vibration sensor, 211. String clamp, 212. Third screw, 213. First hole, 214. Third fixing hole, 215. First fixing hole, 216. Second fixing hole, 217. Fourth fixing hole, 218. First through hole, 219. Second through hole, 220. String clamping groove, 221. Abutment ring, 222. String tuning hole;

[0058] 3. Shell; 31. Second groove; 32. Second fastener; 33. Second hole;

[0059] 4. Handle body; 41. Positioning pin; 42. Display module; 43. Battery cover; 44. Fourth screw; 45. Fifth fixing hole; 46. Sixth fixing hole; 47. Fifth screw; 48. Seventh fixing hole; 49. Third hole; 410. Eighth fixing hole; 411. Battery recess; 412. Battery; 413. Sixth screw; 414. Ninth fixing hole. Detailed Implementation

[0060] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0061] Combination Figure 1-10 As can be seen, the present invention provides a tooth biting force measuring device based on vibrating wire fusion strain, comprising a cover 1, a measuring body 2, a housing 3, and a handle body 4.

[0062] The cover 1 and the shell 3 are respectively recessed to form the first groove 13 and the second groove 31. The two are connected to each other to form a split shell. The cover 1 and the shell 3 serve as the upper and lower structures of the device, respectively, and are used as the force-bearing surfaces that contact the upper and lower teeth.

[0063] In this embodiment, an annular sealing ring 11 is also provided around the periphery of the cover 1, which is installed on the outer edge of the mounting part 14 of the cover 1 to prevent saliva or moisture from entering the device and affecting the electronic components.

[0064] The measuring body 2 is placed within the accommodating space formed by the first groove 13 and the second groove 31. The cover 1 is detachably connected to the measuring body 2 via the first fixing member 23 and the corresponding first fixing groove 12 on the cover 1. The cover 1 and the housing 3 are detachably connected via the second fixing groove 15 on the cover 1 and the second fixing member 32 on the housing 3. This split structure design facilitates maintenance and cleaning. The cover 1 and the housing 3 can be detached from the measuring body 2 for disinfection. At the same time, the handle 4 is placed outside the mouth for the operator to hold, reducing discomfort for the subject during measurement.

[0065] The measuring body 2 is the core sensing component of the device, and it has two symmetrical first protrusions 21 and one second protrusion 22.

[0066] The first protrusion 21 is located on both sides of the recessed part of the measuring body 2, and a first through hole 218 is formed in the horizontal direction inside it. The first through hole 218 is used to accommodate the string clamp 211. After the string clamp 211 is inserted into the first through hole 218, it is used to fix a vibrating string 25 and keep the vibrating string 25 in a prestressed tension state. When subjected to the biting force of teeth, the tension changes and its natural vibration frequency changes accordingly. The first protrusion 21 is equipped with a vibration sensor 210, which is connected to the microcontroller unit through an internal circuit.

[0067] The second protrusion 22 is located at the center of the recessed portion of the measuring body 2, between the two first protrusions 21. Two second through holes 219 are formed horizontally inside the second protrusion 22 for mounting strain gauges 29. The strain gauges 29 are positioned at the deformation-sensitive parts of the measuring body 2 under stress, collecting strain signals caused by the stress to compensate for the amplitude signals collected by the vibrating wire 25. Before being installed in the second through holes 219, the strain gauges 29 are mounted on a mounting plate 24, with strain gauges 29 attached to both sides of the mounting plate 24. To fix the strain gauges 29 in the optimal measuring position, the second protrusion 22 also has fourth fixing holes 217 on both sides of the second through holes 219. A third screw 212 passes through the tenth fixing hole 27 and the fourth fixing hole 217 on the mounting plate 24 to press and fix the strain gauges 29 to the second protrusion 22 of the measuring body 2, thereby ensuring that the strain gauges 29 reliably sense the minute strain generated by the measuring body 2 under the action of tooth biting force. The strain gauge 29 is connected to the microcontroller unit through an internal circuit and is used to compensate or calibrate the frequency measurement of the vibrating wire 25 to improve the measurement accuracy.

[0068] The tops of the first protrusion 21 and the second protrusion 22 are each recessed to form a screw hole structure, serving as the first fixing hole 215 and the second fixing hole 216, respectively. The first fixing hole 215 communicates with the first through hole 218. After aligning with the position of the string clamp 211 and installing the string clamp 211, the first screw 26 is screwed into the first fixing hole 215, with its end abutting against the string clamp 211, firmly fixing the string clamp 211 inside the first protrusion 21, thereby ensuring the stability of the vibrating string 25 during the measurement process. The second screw 28 is screwed into the second fixing hole 216, pressing against the bottom of the second protrusion 22, providing a fixed support for the second protrusion 22, preventing unnecessary displacement of the second protrusion 22 when the measuring body 2 is deformed by force, and further improving the accuracy of the data collected by the strain gauge 29.

[0069] In this embodiment, the vibrating string 25 is securely fixed and tensioned at both ends by string clamps 211 on both sides. The string clamp 211 is a cylindrical piece with a string clamping groove 220 at one end, which allows the vibrating string 25 to pass through and be positioned. The tail end of the string clamp 211 has a protruding abutment ring 221, the diameter of which is slightly larger than the first through hole 218. Therefore, when the string clamp 211 is inserted into the first through hole 218, the abutment ring 221 will be locked outside the first protrusion 21, preventing the string clamp 211 from sliding out axially. The center of the abutment ring 221 has a tuning hole 222, the diameter of which is slightly larger than the vibrating string 25, allowing the use of an adjustment tool (such as a small hex wrench) to adjust the effective length and initial tension of the vibrating string 25. When it is necessary to adjust the effective length and initial tension of the vibrating string 25, the length of the vibrating string 25 is adjusted through the tuning hole 222. After the string clamp 211 is inserted into the first through hole 218, the first screw 26 passes through the first fixing hole 215 at the top of the first protrusion 21 and abuts against the string clamp 211, thereby fixing the string clamp 211. If the string clamp material is elastic, the first screw 26 can further fix the vibrating string 25.

[0070] To securely mount the measuring body 2 within the housing 3 and install the handle body 4, the measuring body 2 and the housing 3 are respectively provided with a first hole 213 and a second hole 33 in the horizontal direction at corresponding positions. When the measuring body 2 is placed into the second groove 31 of the housing 3, the first hole 213 and the second hole 33 are aligned and connected, allowing the positioning pin 41 to be inserted from the side, passing through the housing 3 and the measuring body 2. After the positioning pin 41 is properly inserted, the fifth fixing hole 45 on it corresponds to the third fixing hole 214 on the side wall of the measuring body 2. By screwing in the fourth screw 44, which passes through the third fixing hole 214 and locks into the fifth fixing hole 45, the measuring body 2, the housing 3, and the positioning pin 41 passing through them are all fixed together, preventing the measuring body 2 from shaking or shifting within the housing 3.

[0071] The handle body 4 is used by the operator to hold the device and carries the display and power supply. One end of the handle body 4 is connected to the housing 3. Specifically, the positioning pin 41 extending from the side of the housing 3 is inserted into the corresponding third hole 49 inside the handle body 4. When the positioning pin 41 is inserted into place, the sixth fixing hole 46 on the positioning pin 41 and the seventh fixing hole 48 on the handle body 4 are aligned and coincident in the vertical direction. At this time, by passing the fifth screw 47 through the seventh fixing hole 48 and the sixth fixing hole 46 in sequence and tightening it, the positioning pin 41 can be locked and connected to the handle body 4, preventing the positioning pin 41 from accidentally falling off. In this way, a detachable connection between the measuring body 2 and the handle body 4 is achieved.

[0072] In this embodiment, the handle body 4 integrates a display module 42 for displaying measurement results, which can directly display the real-time measured tooth occlusal force value in digital form for easy reading by the operator. The handle body 4 also has a battery recess 411 to accommodate a battery 412 to provide power to the device; the opening of the battery recess 411 is protected by a battery cover 43. To prevent the battery cover 43 from loosening, the battery recess 411 and the battery cover 43 are respectively provided with an eighth fixing hole 410 and a ninth fixing hole 414. During installation, the two holes are aligned, and the battery cover 43 is fastened to the handle body 4 by passing a sixth screw 413 through the ninth fixing hole 414 and the eighth fixing hole 410 in sequence.

[0073] A vibration sensor 210 is arranged inside or below the first protrusion 21, adjacent to the vibrating string 25. The vibration sensor 210 can be an electromagnetic vibration coil. During operation, the system provides a short pulse to excite the vibrating string 25 and then stops the excitation. The vibrating string 25 vibrates freely at its natural frequency. The coil induces a sinusoidal voltage with the same frequency as the vibrating string 25 in the magnetic field of the permanent magnet, which is then sent to the frequency counting unit. The frequency counting unit inputs the signal, after amplitude limiting and shaping, into the input counting channel of the microcontroller timer, and obtains the frequency value using hardware counting and a high-stability time base.

[0074] Strain gauges 29 are arranged symmetrically to form a full bridge. The bridge output is amplified by the instrument-level differential amplifier of the bridge measurement and preamplification unit, and then input to a high-resolution Δ-Σ type bridge ADC to obtain a digital quantity corresponding to the local strain of the measuring body 2. The microcontroller unit combines the frequency channel and the strain channel and calculates the engagement force according to the calibration function. The result is sent to the display module 42 for real-time display.

[0075] When the device is in use, the upper and lower teeth apply a biting force F to the measuring body 2 through the cover 1 and the shell 3 respectively. The measuring body 2 undergoes a combined bending and compression deformation along the central axis of the second protrusion 22. The strain gauges 29 attached to both sides of the second through hole 219 deform along with the second protrusion 22, resulting in a change in resistance and a change in output voltage. The electrical signal is synchronously acquired through the internal circuit in a full-bridge manner. At the same time, due to the combined bending and compression deformation of the measuring body 2, it also produces a small elastic displacement along the direction of the string clamp 211 connection, which changes the effective distance between the two string clamps 211 and causes a change in the axial tension of the vibrating string 25, which in turn causes a change in the natural frequency of the vibrating string 25, which is collected by the vibration sensor 210 below the first protrusion 21. The vibrating wire 25 is preferably a high-strength metal steel wire, whose effective length and material density are known constants. Its natural vibration frequency is highly sensitive to tension changes but insensitive to temperature and electromagnetic noise, thus stably mapping the tension changes caused by the clamping force into frequency shifts. The full-bridge strain gauge establishes a definite functional relationship between the local strain of the measuring body 2 and the clamping force, which is used for redundant measurement and frequency method compensation calibration. Before the instrument is put into use, the vibrating wire and strain gauge are initially calibrated and zero-point calibrated, including adjusting the string clamp to set the initial tension of the vibrating wire, adjusting the tightness of the mounting plate to set the initial strain of the strain gauge, and recording the vibration frequency of the vibrating wire under no-load conditions. and strain gauge output voltage As a reference value; during the calibration measurement process, the real-time frequency is acquired synchronously. With output voltage The two values ​​are then paired and calculated with the reference value, i.e., the frequency channel is processed using the difference squared (in... (Calculate the frequency difference), the strain channel uses differential processing (to...) Calculate the output voltage difference. Based on the difference, adjust the initial tension of the vibrating string and the initial strain of the strain gauge until the difference meets the error requirements.

[0076] Therefore, the interlocking force F, the vibrating wire frequency f, and the strain gauge strain ε satisfy the following functional relationship:

[0077]

[0078] in, The real-time fundamental frequency of the vibrating string (Hz);

[0079] In this embodiment, the effective length of the vibrating string is 3mm.

[0080] The linear density of the vibrating string is taken as 5.52 × 10⁻⁶ in this embodiment. -4 kg / m

[0081] The initial pretension is 20N, which is set during tuning; in this embodiment, 20N is used.

[0082] For the axial stiffness of the steel string, 7.07 × 10⁻⁶ is used in this embodiment. 5 N / m

[0083] To measure the equivalent flexibility of the main body in the direction of the string clamp connection, 2.4 × 10⁻⁶ is used in this embodiment. -8 m / N

[0084] The output voltage (V) of the strain gauge bridge after amplification.

[0085] For the instrumentation amplifier gain, 500 is used in this embodiment.

[0086] For the conversion factor, the full bridging method is used in this embodiment, and the value is 1.

[0087] The strain gauge sensitivity coefficient is set to 2.1 in this embodiment.

[0088] The voltage set for the bridge circuit is determined by adjusting the strain gauge output voltage based on the average bite force of a person; it is generally greater than 1.1V, and in this embodiment, it is set to 3.3V.

[0089] For strain gauge position calibration, this embodiment uses 1×10⁻⁶ values ​​based on the position. -6 (strain) / N

[0090] To achieve a weighted average, the vibrating wire is used as the primary weight, supplemented by the strain gauge; in this embodiment, a weight of 0.7 is adopted.

[0091] After completing the initial tension calibration of the vibrating wire and the initial strain calibration of the strain gauge, measure the engagement force according to the following steps:

[0092] Step 1: Place the above-mentioned tooth occlusal force measuring device between the pair of upper and lower teeth to be tested, with the cover 1 on the upper tooth side and the shell 3 on the lower tooth side, ensuring close contact with the occlusal surfaces of the upper and lower teeth respectively, and ensuring the device is placed stably. The measuring body 2 is fully inserted into the groove of the cover 1 and the shell 3, and the vibrating string 25 is kept taut in a non-stressed state.

[0093] Step 2: The subject gradually clenches his upper and lower teeth, causing them to apply pressure to the measuring body 2 simultaneously through the cover 1 and the shell 3. As the clenching force increases, the measuring body 2 will undergo a combined bending deformation along the central axis of the second protrusion 22 under pressure, while also undergoing slight elastic deformation along the line connecting the clamps 211.

[0094] Step 3: During the engagement process, the vibrating string 25 inside the measuring body 2 undergoes slight elastic deformation along the line connecting the two clamps 211 due to the slight elastic deformation of the measuring body 2. This changes the effective distance between the two clamps 211 and causes a change in the axial tension of the vibrating string 25, which in turn causes a change in the natural frequency of the vibrating string 25. This change is collected by the vibration sensor 210 below the first protrusion 21. In addition, as the strain gauge 29 undergoes bending deformation along the central axis of the second protrusion 22 following the measuring body 2, the change in the resistance of the strain gauge 29 causes a change in the output voltage, which is directly collected by the internal circuit.

[0095] Step 4: Input the vibration frequency signal of the vibrating wire 25 collected by the vibration sensor 210 and the output voltage signal of the strain gauge 29 collected by the internal circuit to the microcontroller unit, and convert the collected signals into actual tooth biting force values ​​according to the pre-calibrated "frequency, deformation-force" relationship and output them to the display module 42.

[0096] To ensure the accuracy and reliability of the obtained force value, the innovation of this invention lies in using strain gauge deformation as compensation.

[0097] Step 5: The calculated bite force value is displayed in real time via the display module 42 on the handle body 4 for the operator to read and record. If the subject gradually increases or decreases the bite force, the displayed value will change synchronously, achieving real-time monitoring of the applied force. After the measurement is completed, the subject releases their jaw and removes the device. By disassembling the cover 1 and the shell 3, the parts that come into contact with the oral cavity can be cleaned and disinfected, preparing for the next measurement.

[0098] This embodiment accurately measures tooth occlusal force using a vibrating wire sensing principle, successfully integrating force sensing, data acquisition and processing, and result display into a single device. No complex external equipment is required during measurement; the operator can directly read the occlusal force value by holding the device, greatly improving ease of use and clinical applicability. The device adopts a split-type structure design; the cover 1 and shell 3, which contact the teeth, can be easily disassembled for cleaning, while the handheld part is located outside the mouth, ensuring hygiene, safety, and subject comfort during the testing process. The sensing components in this embodiment are small and thin, with minimal impact on normal occlusal posture and no significant change in mandibular position, thus the measured occlusal force more closely approximates the subject's true occlusal force level.

[0099] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. However, the above description is merely a specific embodiment of the present invention, and the technical features of the present invention are not limited thereto. Any other embodiments derived by those skilled in the art without departing from the technical solution of the present invention should be covered within the patent scope of the present invention.

Claims

1. A device for measuring tooth biting force by vibrating wire fusion strain, characterized in that, It includes a cover (1), a measuring body (2), a shell (3), and a handle body (4); The cover (1) and the shell (3) are connected to each other to form a split shell, and the cover (1) and the shell (3) respectively form force-bearing surfaces for contact with the upper and lower teeth; The measuring body (2) is placed in the accommodating space formed by the cover (1) and the shell (3). The measuring body (2) is provided with a vibrating wire (25) and a strain gauge (29). The vibrating wire (25) is configured to change its tension under prestressed tension as the measuring body (2) is subjected to a biting force and the strain gauge (29) is configured to sense the strain of the measuring body (2). The handle body (4) is connected to the housing (3), and a display module (42) is provided on the handle body (4). The device further includes a data acquisition and processing module, which is configured to calculate the biting force value based on the vibration signal of the vibrating wire (25) and the output voltage signal of the strain gauge (29), and output it to the display module (42) for display.

2. The tooth biting force measuring device based on vibrating wire fusion strain according to claim 1, characterized in that, The measuring body (2) includes a first protrusion (21) and a second protrusion (22). The first protrusion (21) is provided with a string clamp (211), and the vibrating string (25) is fixed or adjusted by the string clamp (211). The strain gauge (29) is disposed on the second protrusion (22).

3. The tooth biting force measuring device based on vibrating wire fusion strain according to claim 2, characterized in that, The first protrusion (21) has a first through hole (218) in the horizontal direction, and the string clamp (211) is disposed in the first through hole (218); the string clamp (211) has a string clamping groove (220) for fixing the vibrating string (25) and a string adjustment hole (222) for adjusting the tension of the vibrating string (25).

4. The tooth biting force measuring device based on vibrating wire fusion strain according to claim 3, characterized in that, The top of the first protrusion (21) is provided with a first fixing hole (215) communicating with the first through hole (218). The first screw (26) passes through the first fixing hole (215) and abuts against the string clamp (211) to fix the string clamp (211).

5. The tooth biting force measuring device based on vibrating wire fusion strain according to claim 1, characterized in that, The second protrusion (22) has a second through hole (219) in the horizontal direction. The strain gauges (29) are symmetrically arranged in the second through hole (219) and connected by a full bridge circuit. The top of the second protrusion (22) has a second fixing hole (216). The second screw (28) passes through the second fixing hole (216) and abuts against the bottom of the second protrusion (22) to stabilize the second protrusion (22).

6. The tooth biting force measuring device based on vibrating wire fusion strain according to claim 1, characterized in that, The cover (1) and the shell (3) are respectively provided with a first groove (13) and a second groove (31), which accommodate the measuring body (2); the cover (1) and the measuring body (2) are detachably connected, as are the cover (1) and the shell (3).

7. The tooth biting force measuring device based on vibrating wire fusion strain according to claim 1, characterized in that, The measuring body (2) has a first hole (213) on one side and a second hole (33) on one side of the housing (3). The measuring body (2) and the housing (3) are connected by a positioning pin (41). The positioning pin (41) passes through the corresponding first hole (213) and second hole (33) on the measuring body (2) and the housing (3) and is fixed by screws. The handle body (4) is connected to the housing (3) by the positioning pin (41).

8. The tooth biting force measuring device based on vibrating wire fusion strain according to claim 1, characterized in that, The data acquisition and processing module includes: A vibration sensor is installed on the measuring body (2) to collect the vibration signal of the vibrating string (25); The frequency counting unit is used to obtain the vibration frequency of the vibrating string (25) based on the signal from the vibration sensor; The bridge-type measurement and preamplification unit is used to amplify and convert the voltage signal output by the strain gauge (29) into an analog-to-digital signal. The microcontroller unit is used to calculate the bite force value based on the vibration frequency and the amplified strain signal, according to a preset calibration relationship.

9. The tooth biting force measuring device based on vibrating wire fusion strain according to claim 1, characterized in that, The expression for calculating the bite force is: ； in, This is the real-time fundamental frequency of the vibrating string; The effective length of the vibrating string; The linear density of the vibrating string; The initial pretension of the vibrating string; The axial stiffness of the vibrating string; To measure the equivalent compliance of the main body in the direction of the string clamp connection; The output voltage of the strain gauge bridge after amplification; For instrument-grade differential amplifier gain; These are conversion factors; The strain gauge sensitivity coefficient; Set the voltage for the bridge circuit; The values ​​are used to calibrate the position of the strain gauge. To integrate weights, .

10. A method for measuring tooth occlusal force by vibrating wire fusion strain, comprising using the tooth occlusal force measuring device by vibrating wire fusion strain as described in any one of claims 1-9, characterized in that, Includes the following steps: The measuring device is placed between the upper and lower teeth to be measured; Apply a biting force and collect the tension and frequency changes of the vibrating wire (25) caused by the deformation of the measuring body (2) and the deformation signal of the strain gauge (29); The bite force value is calculated based on the vibration signal of the vibrating wire (25) and the output voltage signal of the strain gauge (29); the bite force value is displayed through the display module (42).

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