Invisible appliance based on transparent piezoelectric film and design method thereof

Abstract

The invention discloses an invisible appliance based on a transparent piezoelectric film and a design method thereof. A perioral muscle pressure sensor is installed on the lip / cheek lingual surface of teeth of the invisible orthodontic appliance, an occlusal force sensor is installed on the occlusal surface, and a tooth surface counter-acting force sensor is installed on the inner side tissue surface, so that dynamic changes of perioral muscle pressure, occlusal force and orthodontic force can be monitored in real time. The invisible orthodontic appliance provided by the invention integrates a sensor with high piezoelectric coefficient and high flexibility, has high sensitivity and accuracy, can be used for testing dynamic changes of orthodontic mechanics and evaluating the influence of perioral muscle pressure, occlusal force and the like on treatment during physiological processes of chewing, breathing, swallowing, language and the like of a patient; a doctor optimizes an orthodontic scheme through the PC terminal and pays attention to the association between oral functional mechanics and malocclusion, bad oral habits, bruxism, temporomandibular joint disorder and other diseases, and the efficiency and accuracy of oral health management are improved.

Description

Technical Field

[0001] The present invention belongs to the field of oral appliances and is an invisible appliance, and specifically relates to a transparent film sensing appliance that monitors perioral muscle pressure, occlusal force and orthodontic correction force changes in real time and integrates "oral functional mechanics" and a design method thereof. Background Art

[0002] Oral functional mechanics affects the patient's physiological processes such as chewing, breathing, swallowing, and language through the interaction of multiple forces such as occlusal force and perioral muscle pressure, and plays an important role in the formation and development of malocclusion. Reasonable application of orthodontic correction force can help correct these problems and prevent the aggravation of malocclusion; poor oral functional force can affect the efficiency of orthodontic treatment and even lead to the failure of orthodontic treatment. Therefore, it is of great significance to study the impact of oral functional mechanics on malocclusion.

[0003] Bite force is crucial to oral health. Abnormal or unbalanced bite force often leads to malocclusion, bruxism and temporomandibular joint disorder. Abnormal bite force can cause teeth to shift or tilt. Bad oral habits such as tongue pushing teeth and lip biting can cause uneven local pressure and lead to malocclusion. Patients with bruxism often suffer from tooth wear and temporomandibular joint damage due to excessive bite force, causing pain and dysfunction. By detecting and adjusting the bite force, these diseases can be effectively prevented and oral function and health can be maintained. However, traditional bite force measurement equipment is often large in size and complicated to operate, making it difficult to fully simulate the real chewing environment. In addition, there are challenges in capturing the dynamic changes in bite force, and the patient's cooperation and state fluctuations will further affect the accuracy of the measurement.

[0004] The perioral muscles include the orbicularis oris, buccinator, and mandibular muscles. Lip pressure is mainly generated by the orbicularis oris, which is responsible for lip closure and movement. The upper lip is closed by the orbicularis oris, while the lower lip is closed by the mentalis and orbicularis oris. Lip muscle pressure also affects jaw movement and the muscle function of the temporomandibular joint. The force exerted by the perioral muscles has an important influence on tooth eruption, dental arch morphology and stability, and is also closely related to activities such as swallowing, chewing, and speech. Muscle force imbalance can lead to problems such as dysphagia and sleep apnea, and is related to malocclusion. Orthodontic treatment may change the position and pressure of the lips, affecting the treatment effect and stability. Dysfunction of the perioral muscles, such as clenching or grinding, will put a burden on the temporomandibular joint, causing pain and dysfunction, and leading to joint disorder. Therefore, static and dynamic perioral muscle force monitoring is very important. However, compared with traditional measuring instruments, instruments for testing muscles are difficult to fix in the mouth. Researchers have tried to use a small balloon as a pressure sensor in the oral cavity (CN116982981 A); some researchers have also used thin-film pressure sensors outside the mouth to measure the strength of the perioral muscles under specific action states (CN 114432656 A). Later, a design was made to install a miniature pressure sensor on an acrylic resin base, and a single strain gauge or pressure sensor was installed on a lip guard or a removable orthodontic appliance to sense the pressure, or some other methods were used. There are also strain gauges bonded to three different teeth and connected to an extraoral pressure sensor to record the pressure of the lips on the teeth when speaking. However, the above-mentioned detection instruments have the following disadvantages: (1) They only focus on one area of ​​interest in the oral cavity. (2) Due to different measurement techniques, there are great differences between these studies, and the thickness and design of different devices are different, which has a great impact on pressure measurement. (3) Chewing, sucking and blowing are only short-term muscle changes, and many devices cannot provide continuous pressure readings during all functions of the oral cavity (i.e. swallowing, chewing and speaking). Because the pressure changes in different parts of the body during swallowing are sequential and precisely coordinated.

[0005] Invisible braces are made using CAD / CAM technology, using a series of braces and the rebound force generated by tooth displacement to form orthodontic correction force to move teeth. Integrating high-precision sensors in invisible braces can achieve real-time monitoring of the force applied to teeth. On the one hand, it measures the changes in oral dynamic forces such as occlusal force and perioral muscle force, and on the other hand, it detects the changes in the magnitude of the applied orthodontic force in real time, which helps orthodontists to adjust the treatment plan in time according to the actual situation of the patient, thereby improving the accuracy and efficiency of treatment. With the continuous advancement of sensing technology, microelectronics technology and data analysis capabilities, integrated and intelligent braces solutions are gradually becoming possible. Through force sensors and smart devices, doctors can remotely monitor the patient's correction status, and patients can also understand their own dental correction progress in real time through mobile devices. This intelligent detection device can not only improve the patient's treatment experience, but also provide more personalized treatment plans for the orthodontic field.

[0006] However, for the transmission of pressure signals of oral functional mechanics, the sensors in the existing technologies: (1) Although magnetic sensors exhibit high acoustic performance at low pressures, they also have many limitations. They are based on electromagnetic coils and are heavy; (2) Most of the current thin film sensors require high voltage drive. The high operating voltage of piezoelectric materials limits their widespread application in many existing technologies; (3) Piezoelectric ceramic sensors are opaque and heavy. Summary of the invention

[0007] In order to solve the problems existing in the background technology, the present invention provides an invisible brace based on transparent piezoelectric film and a design method thereof. The present invention uses 3D printing technology to integrate ZnO-PZT / PVDF-P (VDF-TrFE) piezoelectric film sensors, so that the invisible brace has self-generated electricity and memory functions, and can monitor the dynamic changes of perioral muscle pressure in different states of rest, swallowing and chewing, and realize remote data transmission through Bluetooth transmission, and then display and analyze the differences in muscle changes on the terminal APP and the relationship between malocclusion, bad oral habits such as mouth breathing, temporomandibular joint disorders and other diseases, so as to achieve the optimal design of the invisible brace.

[0008] The technical solution adopted by the present invention is:

[0009] 1. An invisible brace based on transparent piezoelectric film

[0010] Perioral muscle pressure sensors, wherein a plurality of perioral muscle pressure sensors are mounted one by one on the lip / cheek-lingual surface of the teeth corresponding to the invisible orthodontic appliance body, and the perioral muscle pressure sensors are used to sense the pressure changes of the perioral muscles and generate corresponding electrical signals;

[0011] A bite force sensor, wherein a plurality of the bite force sensors are mounted one by one on the occlusal surfaces of the teeth corresponding to the invisible orthodontic appliance body, and the bite force sensors are used to sense changes in the bite force and generate corresponding electrical signals;

[0012] Tooth surface reaction force sensor, a plurality of tooth surface reaction force sensors are installed one by one on the inner tissue surface of the corresponding teeth of the invisible braces body. The tooth surface reaction force sensor is used to sense the pressure change of the orthodontic correction force applied by the invisible braces body on the tooth surface and generate a corresponding electrical signal.

[0013] The perioral muscle pressure sensor is a transparent ZnO piezoelectric thin film integrated circuit chip.

[0014] The bite force sensor is a transparent flexible PZT / PVDF piezoelectric thin film integrated circuit chip.

[0015] The tooth surface reaction force sensor is a P (VDF-TrFE) copolymer piezoelectric thin film integrated circuit chip.

[0016] The perioral muscle pressure sensor, the bite force sensor and the tooth surface reaction force sensor are all sensors that include energy storage devices.

[0017] During the printing process of the invisible orthodontic appliance body, embedding positions for the sensors are reserved in the photosensitive resin, so that the perioral muscle pressure sensor, the bite force sensor and the tooth surface reaction force sensor are embedded in corresponding positions.

[0018] 2. A design method for invisible braces based on transparent piezoelectric film

[0019] Step 1: Determine the corresponding initial embedding positions of the perioral muscle pressure sensor, the bite force sensor and the tooth surface reaction force sensor at different tooth positions according to the dental appliance model;

[0020] Step 2: After adjusting the corresponding initial embedding positions of the perioral muscle pressure sensors, bite force sensors and tooth surface reaction force sensors at different tooth positions according to the oral structure model, the corresponding optimized embedding positions are obtained, so that each perioral muscle pressure sensor collects the pressure changes of the perioral muscles at the corresponding teeth, each bite force sensor collects the changes of the bite force at the corresponding teeth, and each tooth surface reaction force sensor collects the reaction force of the corresponding tooth surface, thereby completing the design of the invisible braces.

[0021] The design method further comprises the following steps:

[0022] Step 3: After the invisible braces are worn in the user's mouth, the real-time data of perioral muscle pressure, bite force and orthodontic force are determined according to the signals sent by each sensor. Then, the dental braces model and the embedding position of each sensor are optimized according to the real-time data of perioral muscle pressure, bite force and orthodontic force to complete the optimized design of the invisible braces.

[0023] The beneficial effects of the present invention are:

[0024] (1) Integrate the performance of different piezoelectric film sensors: PVDF has good flexibility and transparency, and is suitable for the occlusal surface of invisible braces. It can sense the large forces generated during occlusion and is stable in force feedback. Embedding PZT into PVDF can significantly improve the piezoelectric coefficient while maintaining a certain degree of transparency and flexibility, which is suitable for detecting strong occlusal forces. P(VDF-TrFE) copolymer has significant improvements in piezoelectricity and mechanical stability, and is suitable for detecting milder orthodontic forces. ZnO film, with its transparency and innovative piezoelectric sensing capabilities, is suitable for detecting tiny perioral muscle forces.

[0025] (2) Sensors with high piezoelectric coefficient and high flexibility: Transparent flexible PZT / PVDF piezoelectric film can generate up to 81.25gW / cm 3 The maximum sensitivity of the fiber is 560mV / N. PZT has high sensitivity and stability, while PVDF has good flexibility and lightness.

[0026] (3) Transparency and high sensitivity: ZnO film and P (VDF-TrFE) copolymer have transparency and piezoelectric effect, which can accurately detect small changes in muscle force and slight changes in orthodontic force on the lip and tongue surface, and can match well with the transparent characteristics of invisible braces. Piezoelectric film is very sensitive to dynamic stress. The sensitivity of 28μm thick PVDF is typically 10-15mV / microstrain. When a small force is applied longitudinally, a large stress will be generated in the lateral direction. The braces are very thin and can generate vibrations on the diaphragm without affecting basic oral movements, without sacrificing the visibility of the transparent diaphragm, and without adverse magnetic field emission problems, thereby improving accuracy.

[0027] (4) Combination of self-generation and energy storage functions: Piezoelectric film can generate electricity through various mechanical stresses in the mouth (such as chewing or swallowing) without the need for an external power supply. This self-generation function makes the invisible braces do not require an external power supply, enhancing the convenience of use. The integrated energy storage device (such as a micro capacitor or battery) can store the generated electricity, thereby ensuring that the sensor and wireless transmission module can continue to work while the braces are worn.

[0028] (5) Real-time dynamic monitoring and analysis of perioral muscle pressure and bite force: Through the wireless module, real-time data is transmitted to the mobile phone APP and computer PC for real-time analysis and feedback. Through dynamic monitoring and detailed data analysis, doctors can obtain more accurate oral function data, so as to better adjust and optimize the correction plan and improve the treatment effect. It can detect abnormal pressure changes or abnormal oral behavior in time, helping to identify and solve potential oral problems or appliance discomfort problems early. Timely detection of abnormal pressure during orthodontic treatment or the retention stage and appropriate intervention play an important role in post-orthodontic retention and long-term effective functional stability. Through the integrated piezoelectric sensor, the perioral muscle pressure of a person in different physiological states such as resting state, swallowing and chewing can be monitored in real time. This dynamic monitoring capability can provide detailed oral function data to help doctors more accurately evaluate patients' oral health and correction effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A three-dimensional schematic diagram of an invisible brace appliance containing a sensor.

[0030] Figure 2 This is a schematic top view of the outer side of an invisible brace appliance containing a sensor.

[0031] Figure 3 Schematic diagram of the inner tissue surface of the invisible braces containing sensors.

[0032] Figure 4 This is the principle framework diagram of the invisible braces.

[0033] Figure 5 This is a schematic diagram of the structure of a piezoelectric thin film integrated circuit chip.

[0034] Figure 6 Schematic diagram of the tooth model in the design method of the present invention.

[0035] Figure 7 This is a structural framework diagram of a piezoelectric thin film integrated circuit chip.

[0036] In the figure: 1. Invisible braces body; 2. Transparent ZnO piezoelectric thin film integrated circuit chip; 3. Transparent flexible PZT / PVDF piezoelectric thin film integrated circuit chip; 4. P(VDF-TrFE) copolymer piezoelectric thin film integrated circuit chip; 5. Piezoelectric film; 6. Electrode; 7. Coating; 8. Flexible substrate; 9. Dielectric film; 10. Internal electrode; 11. Wire; 12. Bridge rectifier; 13. Alternating current; 14. Direct current; 15. Input signal; 16. Amplifier LM358; 17. Output signal; 18. SAW filter; 19. Microcontroller (MCU); 2 0. Digital-to-analog converter (DAC); 21. nRF52832 Bluetooth module; 22. Wireless transmission; 23. Patient-side mobile phone APP; 24. Pressure wave signal; 25. Remote transmission; 26. Doctor-side computer; 27. Display interface; 28. Pressure waveform signal; 29. ​​Stress distribution cloud map; 30. The lingual pressure of the central incisor is too high; 31. The occlusal force of the second molar is too high; 32. The distal cervical pressure of the canine is too high; 33. The labial displacement of the central incisor is increased and the lingual clearance is increased; 34. The second molar is increased in depression and the clearance is reserved; 35. The mesial displacement of the canine is increased and the cervical clearance is increased. DETAILED DESCRIPTION

[0037] The method of the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] The present invention proposes an invisible brace based on transparent piezoelectric film, which includes various types of transparent film sensors with piezoelectric film and energy storage device integrated inside, and is used to monitor the dynamic changes of perioral muscle pressure, bite force and orthodontic correction force. Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, specifically including:

[0039] Perioral muscle pressure sensors: several perioral muscle pressure sensors are installed one by one on the lip / cheek-lingual surface of the teeth corresponding to the invisible orthodontic appliance body 1. The perioral muscle pressure sensors are used to sense the pressure changes of the perioral muscles and generate corresponding electrical signals, and send the electrical signals to the host computer;

[0040] Bite force sensor: several bite force sensors are installed one by one on the occlusal surface of the corresponding teeth of the invisible orthodontic appliance body 1. The bite force sensor is used to sense the change of bite force and generate corresponding electrical signals, and send the electrical signals to the host computer;

[0041] Tooth surface reaction force sensor, a plurality of tooth surface reaction force sensors are installed one by one on the inner tissue surface of the corresponding teeth of the invisible braces body 1. The tooth surface reaction force sensor is used to sense the pressure change of the orthodontic correction force applied by the invisible braces body 1 on the tooth surface and generate a corresponding electrical signal, and send the electrical signal to the host computer.

[0042] The perioral muscle pressure sensor is a transparent ZnO piezoelectric thin film integrated circuit chip 2. The transparency and piezoelectric sensing ability of the ZnO film are suitable for detecting tiny perioral muscle forces. The bite force sensor is a transparent and flexible PZT / PVDF piezoelectric thin film integrated circuit chip 3. The PZT / PVDF composite film provides excellent piezoelectric response in strong bite force monitoring while maintaining a certain flexibility and transparency. The tooth surface reaction force sensor is a P (VDF-TrFE) copolymer piezoelectric thin film integrated circuit chip 4. The P (VDF-TrFE) copolymer has good transparency and sensitivity to slight orthodontic forces. Piezoelectric film combined with self-generated electricity converts mechanical energy into electrical energy through the piezoelectric effect, collects energy and connects to self-powered equipment, which is a key technology to break through the power supply of intraoral wireless devices. The present invention utilizes the characteristics of the above three films and combines piezoelectric films to construct three different piezoelectric thin film integrated circuit chips. The material selection for different mechanical testing parts of the transparent film sensor has special application scenarios. The ZnO film is suitable for detecting tiny perioral muscle forces, the PZT / PVDF composite film remains flexible during strong bite force monitoring, and the P(VDF-TrFE) copolymer has good transparency and sensitivity to slight orthodontic forces.

[0043] like Figure 5 and Figure 7As shown, each piezoelectric thin film integrated circuit chip structurally includes a piezoelectric film 5, an electrode 6, a coating 7, a flexible substrate 8, a dielectric film 9, an internal electrode 10, a wire 11, a bridge rectifier 12, an input signal 15, an amplifier 16, an output signal 17, a SAW filter 18, a microcontroller 19 and a digital-to-analog converter 20; corresponding electrodes 6 are arranged on both sides of the piezoelectric film 5, and each electrode 6 is coated with a corresponding coating 7. The piezoelectric film 5, the electrode 6 and the coating 7 are installed in the flexible substrate 8, and the electrodes 6 on both sides of the piezoelectric film 5 are connected to the corresponding wires 11. The micro-capacitor composed of a dielectric film 9 and an internal electrode 10 is connected, and the output signal of the micro-capacitor is converted into an alternating current 13 after a bridge rectifier 12, and the alternating current 13 is converted into a direct current 14. The signal in the form of direct current 14 is used as the input signal 15 of the amplifier 16. The output signal 17 of the amplifier 16 is sent to the microcontroller 19 after passing through the SAW filter 18 and the digital-to-analog converter (DAC) 20 in turn. The microcontroller 19 is also connected to the energy storage device through the charging management circuit to test the power generation efficiency, energy storage capacity and stability of the entire system to ensure its reliability and effectiveness in practical applications. The energy storage device is a micro-capacitor or a battery. The design of the rectifier circuit and the charging management circuit has efficient energy conversion and management functions to improve the overall performance and stability of the system. The microcontroller (MCU) 19 sends it to the patient-side mobile phone APP 23 and the doctor-side computer 26 in the form of wireless transmission 22 through the Bluetooth module 21, and the pressure wave signal 24 is displayed in the patient-side mobile phone APP 23 to display the dynamic changes of the perioral muscle pressure in real time. In this embodiment, the model of the amplifier is LM358; the model of the Bluetooth module is nRF52832.

[0044] Perioral muscle pressure sensor, bite force sensor and tooth surface reaction force sensor are all sensors that contain energy storage devices, that is, the sensor can store the electrical energy generated by the piezoelectric film in the energy storage device without the need for an external power supply. The energy storage device can maintain electrical energy storage for a long time under pressure changes and has a high charge and discharge cycle life.

[0045] During the printing process of the invisible braces body 1, the photosensitive resin material has excellent light curing performance and mechanical properties. The embedding positions of each sensor are reserved in the photosensitive resin, so that the perioral muscle pressure sensor, the bite force sensor and the tooth surface reaction force sensor are embedded in the corresponding positions to ensure the strength and transparency of the printed part, and to ensure that it can work effectively in the invisible braces without interfering with the patient's comfort. The transparent film sensor has excellent flexibility and comfort, and is suitable for long-term wear inside the mouth.

[0046] The present invention also proposes a design method of an invisible orthodontic appliance based on a transparent piezoelectric film, the method comprising the following steps:

[0047] Step 1: Determine the corresponding initial embedding positions of the perioral muscle pressure sensor, the bite force sensor and the tooth surface reaction force sensor at different tooth positions according to the dental appliance model;

[0048] Step 2: After adjusting the corresponding initial embedding positions of the perioral muscle pressure sensors, bite force sensors and tooth surface reaction force sensors at different tooth positions according to the oral structure model, the corresponding optimized embedding positions are obtained, so that each perioral muscle pressure sensor collects the pressure changes of the perioral muscles at the corresponding teeth, each bite force sensor collects the changes of the bite force at the corresponding teeth, and each tooth surface reaction force sensor collects the reaction force of the corresponding tooth surface, thereby completing the design of the invisible braces.

[0049] Step 3: After the invisible braces are worn in the user's mouth, the real-time data of perioral muscle pressure, bite force and orthodontic force are determined according to the signals sent by each sensor. Then, the dental braces model and the embedding position of each sensor are optimized according to the real-time data of perioral muscle pressure, bite force and orthodontic force to complete the optimized design of the invisible braces.

[0050] The specific implementation process is as follows:

[0051] (1) Preparation of transparent ZnO piezoelectric film:

[0052] 1) Substrate preparation: Select a substrate such as silicon wafer, glass or flexible material. Clean the substrate: Use acetone or ethanol for ultrasonic cleaning, rinse with deionized water and blow dry with nitrogen.

[0053] 2) Sputtering system preparation: Select ZnO target, use argon (Ar), which can be mixed with a small amount of oxygen (O2), and control the substrate temperature to 200℃~500℃.

[0054] 3) Sputtering condition setting: vacuum pressure is adjusted to 5-20 mTorr, sputtering power is set to 100 W-300 W, and sputtering time is adjusted according to the required film thickness of 100 nm-2 μm.

[0055] 4) Thin film deposition: Sputtering is started in an argon environment, the ZnO target is excited, and Zn and O atoms are deposited on the substrate to form a ZnO thin film.

[0056] 5) Annealing treatment is performed at 400°C to 600°C to improve the crystal quality and piezoelectric properties of the film.

[0057] (2) Preparation of transparent flexible PZT / PVDF piezoelectric film:

[0058] 1) Preparation of precursor solution: N,N-dimethylformamide (DMF) and acetone were mixed in an appropriate ratio, PVDF powder was added, and the mixture was stirred with a magnetic stirrer and subjected to ultrasonic treatment for 30 minutes.

[0059] 2) Pretreatment of ceramic particles: PZT ceramic particles were placed in an appropriate amount of anhydrous ethanol, subjected to ultrasonic treatment for 3 hours and then dried.

[0060] 3) Preparation of composite materials: The pretreated PZT particles were added to the PVDF precursor solution, and the mixed solution was ultrasonically treated for 20 minutes.

[0061] 4) Electrospinning preparation: Ensure that the ambient humidity is maintained at 75%-85%, load the prepared precursor solution into the sprayer of the electrospinning equipment, adjust the voltage, the distance from the nozzle to the collector and the feed rate, and start the electrospinning process to form the piezoelectric composite fiber membrane.

[0062] 5) Post-treatment: The piezoelectric composite fiber membrane is taken out from the collector and dried in a ventilated environment, and then placed in a polarization device, and an electric field is applied for polarization. Usually, a high electric field of 20-30 kV / cm is selected for treatment.

[0063] (3) Preparation of P(VDF-TrFE) copolymer piezoelectric films

[0064] 1) P(VDF-TrFE) powder and DMF were mixed in proportion, stirred and then ultrasonically treated for 30 minutes.

[0065] 2) Thin film preparation: The solution was coated on a silicon wafer substrate by spin coating (2000-4000 rpm) and dried at 60°C.

[0066] 3) Thermal annealing at a temperature of 80°C to 120°C for 30 minutes to 1 hour.

[0067] 4) Place the film in a polarization device and apply a high electric field (20-30 kV / cm) for polarization for several minutes.

[0068] (4) Design circuit for integration of piezoelectric film and energy storage device

[0069] 1) Integration of piezoelectric film and electrode: Use sputtering, CVD or PVD techniques to evenly deposit electrode materials on the surface of the piezoelectric film and design the electrode layout.

[0070] 2) Use a microcapacitor as an energy storage device and connect the energy storage device to the electrodes of the piezoelectric film to ensure good electrical contact.

[0071] 3) Signal conditioning circuit design: Use a bridge rectifier to convert the AC power generated by the piezoelectric film into DC power; design a filter and add a voltage regulator circuit to ensure that the output voltage is stably maintained at 1V to 10V, with a power of approximately 50mW.

[0072] 4) Design a circuit to monitor the working status of the piezoelectric film and the charging status of the energy storage device.

[0073] (5) Design circuit of mechanical signal collection and Bluetooth acquisition module

[0074] 1) Add a signal acquisition module to the aforementioned integrated circuit to amplify and filter the charge signal from the piezoelectric sensor.

[0075] 2) Add the operational amplifier LM358, which amplifies the signal to improve the readability of the signal.

[0076] 3) Add a SAW filter and use the SAW filter to remove high-frequency noise to ensure the accuracy of the signal.

[0077] 4) Control circuit design: The microcontroller (MCU) performs data acquisition and processing and generates analog signals through the digital-to-analog converter (DAC).

[0078] 5) Connect the nRF52832 Bluetooth module to the signal processing circuit and design the circuit to meet the power supply and data transmission requirements of the Bluetooth module to ensure that the module can work stably.

[0079] 6) Integration and layout design: Draw a complete circuit schematic, ensure that all components are connected correctly, and design a circuit board (PCB) to obtain a transparent ZnO piezoelectric thin film integrated circuit chip 2, a transparent flexible PZT / PVDF piezoelectric thin film integrated circuit chip 3, and a P (VDF-TrFE) copolymer piezoelectric thin film integrated circuit chip 4.

[0080] (6) Production of invisible braces containing transparent film sensor chips:

[0081] 1) Use CAD software to design a high-precision prototype model of the invisible braces to ensure that the shape conforms to the oral anatomy.

[0082] 2) Reserve appropriate space and structure near the lip / cheek and tongue surface to embed the transparent ZnO piezoelectric thin film integrated circuit chip 2 to ensure that it can be correctly embedded and maintain good functionality.

[0083] 3) A suitable space and structure are reserved on the occlusal surface to embed the transparent flexible PZT / PVDF piezoelectric thin film integrated circuit chip 3, ensuring that it can be correctly embedded and maintain good functionality.

[0084] 4) A suitable space and structure are reserved on the inner tissue surface to embed the P (VDF-TrFE) copolymer piezoelectric thin film integrated circuit chip 4, ensuring that it can be correctly embedded and maintain good functionality.

[0085] 5) Select a high-resolution photosensitive resin 3D printer and set the printing parameters, including a layer thickness of 0.8 mm. Print the photosensitive resin of the invisible braces layer by layer according to the design, and monitor the temperature, light and other parameters during the printing process to ensure the quality of each layer.

[0086] 6) During the printing process of each layer, according to the design requirements, the pre-processed sensor is embedded in the designed position through precise mechanical operation or automated equipment, the output performance and stability of the circuit are tested, and the aforementioned circuit design is optimized based on the test results.

[0087] 7) Clean the uncured resin using an appropriate solvent to obtain a clear surface.

[0088] (7) Wireless transmission module and design circuit

[0089] 1) Wireless data transmission: After the signal processing is completed, the signal is transmitted to the host computer through the nRF52832 Bluetooth module, and the maximum effective transmission distance is about 12 meters.

[0090] 2) Develop a mobile phone APP that connects to the invisible braces via Bluetooth and is used to receive the signals sent by the Bluetooth module of the invisible braces to the host computer.

[0091] 3) The software is designed to utilize signal processing codes (such as Erid6 programming) to process and store the signals, and to display the pressure waveform signal and the stress distribution cloud diagram on the user's display interface 27 .

[0092] 4) The signal is remotely transmitted to the doctor's PC and doctor's APP in real time. The doctor's PC and doctor's APP are used to remotely monitor the invisible braces and detect and deeply analyze the received signals.

[0093] (8) Optimal design of invisible braces based on oral functional mechanics analysis

[0094] 1) Record the pressure waveform signal 28, denoise and filter the collected pressure waveform, and apply it to the dental arch model as a boundary condition. Use Abaqus software to calculate and extract stress distribution data to generate a dynamic visual stress distribution cloud map 29.

[0095] 2) Analyze the stress distribution cloud diagram and evaluate the stress effect. Figure 6 As shown, the stress distribution was evaluated, with special attention paid to the high-pressure areas on the lingual side of the central incisor and the distal cervical part of the canine. Figure 6The results showed that the lingual pressure on the incisor was too high 30 and the distal cervical pressure on the canine was too high 32. The problem of the excessive occlusal force on the second molar 31 needed to be analyzed in detail.

[0096] 3) Set the optimized displacement target load at different sites to ensure uniformity and directionality of effective orthodontic force loading: for example, increase the labial displacement of the central incisor and increase the lingual clearance by 33, reduce the lingual pressure, and reserve the lingual clearance; for example, adjust the occlusal force distribution of the second molar, increase the depression of the second molar, and reserve the clearance by 34; for example, increase the mesial displacement of the canine and increase the clearance by 35 in the neck, reduce the distal neck pressure, and reserve the neck clearance.

[0097] 4) Adjust the design parameters of the invisible braces: optimize the displacement load of the braces according to the pressure distribution, adjust the geometry and force direction of the braces in combination with simulation, and verify the stress distribution effect of the optimized design.

[0098] Finally, it should be noted that the above embodiments and explanations are only used to illustrate the technical solution of the present invention rather than to limit it. Those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope disclosed in the technical solution of the present invention, which should be included in the scope of protection of the claims of the present invention.

Claims

1. An invisible brace based on transparent piezoelectric film, characterized in that: include: Perioral muscle pressure sensors, wherein a plurality of the perioral muscle pressure sensors are mounted one by one on the labial / buccal-lingual surfaces of the teeth corresponding to the invisible orthodontic appliance body (1), and the perioral muscle pressure sensors are used to sense pressure changes in the perioral muscles and generate corresponding electrical signals; A bite force sensor, wherein a plurality of the bite force sensors are mounted one by one on the bite surfaces of the invisible orthodontic appliance body (1) corresponding to the teeth, and the bite force sensors are used to sense changes in bite force and generate corresponding electrical signals; A tooth surface reaction force sensor, wherein a plurality of tooth surface reaction force sensors are installed one by one on the inner tissue surface of the corresponding teeth of the invisible braces body (1), and the tooth surface reaction force sensors are used to sense the pressure change of the orthodontic correction force applied by the invisible braces body (1) on the tooth surface and generate a corresponding electrical signal.

2. The invisible brace based on transparent piezoelectric film according to claim 1, characterized in that: The perioral muscle pressure sensor is a transparent ZnO piezoelectric thin film integrated circuit chip (2).

3. The invisible brace based on transparent piezoelectric film according to claim 1, characterized in that: The bite force sensor is a transparent flexible PZT / PVDF piezoelectric thin film integrated circuit chip (3).

4. The invisible brace based on transparent piezoelectric film according to claim 1, characterized in that: The tooth surface reaction force sensor is a P (VDF-TrFE) copolymer piezoelectric thin film integrated circuit chip (4).

5. The invisible brace based on transparent piezoelectric film according to claim 1, characterized in that: The perioral muscle pressure sensor, the bite force sensor and the tooth surface reaction force sensor are all sensors that include energy storage devices.

6. The invisible brace based on transparent piezoelectric film according to claim 1, characterized in that: During the printing process of the invisible orthodontic appliance body (1), embedding positions for the sensors are reserved in the photosensitive resin, so that the perioral muscle pressure sensor, the bite force sensor and the tooth surface reaction force sensor are embedded in corresponding positions.

7. A design method for an invisible brace appliance based on a transparent piezoelectric film, characterized in that: The following steps are involved: Step 1: Determine the corresponding initial embedding positions of the perioral muscle pressure sensor, the bite force sensor and the tooth surface reaction force sensor at different tooth positions according to the dental appliance model; Step 2: After adjusting the corresponding initial embedding positions of the perioral muscle pressure sensors, bite force sensors and tooth surface reaction force sensors at different tooth positions according to the oral structure model, the corresponding optimized embedding positions are obtained, so that each perioral muscle pressure sensor collects the pressure changes of the perioral muscles at the corresponding teeth, each bite force sensor collects the changes of the bite force at the corresponding teeth, and each tooth surface reaction force sensor collects the reaction force of the corresponding tooth surface, thereby completing the design of the invisible braces.

8. The design method of an invisible brace appliance based on a transparent piezoelectric film according to claim 7, characterized in that: The design method further comprises the following steps: Step 3: After the invisible braces are worn in the user's mouth, the real-time data of perioral muscle pressure, bite force and orthodontic force are determined according to the signals sent by each sensor. Then, the dental braces model and the embedding position of each sensor are optimized according to the real-time data of perioral muscle pressure, bite force and orthodontic force to complete the optimized design of the invisible braces.

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