Flexible magnetic modified wearable piezoelectric repair tooth socket

Abstract

The invention belongs to the technical field of biomedical instruments, and particularly relates to a flexible magnetic modified wearable piezoelectric repair tooth socket. Comprising a flexible carrier and a functional composite layer, the flexible carrier serves as a substrate, and the functional composite layer is arranged on the flexible carrier; the functional composite layer comprises a first PU packaging layer, a first magnetic film modification layer, a piezoelectric functional layer, a second magnetic film modification layer and a second PU packaging layer which are sequentially arranged from top to bottom. According to the piezoelectric functional layer, parameters such as the occlusion pressure range, the flexible structure design and the action area can be comprehensively adjusted according to the actual application scene, the target output voltage value is achieved, and personalized customization is supported. And by introducing the magnetic film mutual exclusion layer, the stability of the piezoelectric device is improved.

Description

Technical Field

[0001] This invention belongs to the field of biomedical device technology, specifically relating to a flexible magnetically modified wearable piezoelectric restorative dental brace. Background Technology

[0002] With increasing public awareness of oral health, occult gingivitis, characterized by its high prevalence and low treatment rate, is coming into focus. Gingivitis is a nonspecific inflammation caused by dental plaque on the tooth surface, primarily occurring in the free gingiva and gingival papillae, and in severe cases, affecting the attached gingiva, but not other deep tissues surrounding the teeth. Clinically, treatment involves mechanical scaling to remove tartar and control plaque, as well as topical antibacterial agents and systemic antibiotics, such as 1% hydrogen peroxide solution and metronidazole. However, excessive cleaning can lead to periodontal sensitivity and affect the reattachment of the periodontal ligament; incomplete scaling may develop into chronic periodontitis; and drug treatment presents the problem of drug resistance.

[0003] When a patient's dental disease is severe and cannot be preserved through other treatments, tooth extraction is often the only option. After extraction, significant and irreversible bone resorption occurs in the alveolar bone, leading to alveolar ridge atrophy and increasing the difficulty and complexity of future restorations. Clinically, extraction site preservation techniques (minimally invasive extraction + use of bone replacement materials + barrier membranes) can prevent or mitigate this resorption. However, this technique is more complex, time-consuming, and the materials used (deproteinized bovine bone mineral DBBM, advanced absorbable collagen barrier membranes, and growth factor rhBMP-2) are expensive, and may also introduce additional infection risks.

[0004] Electric field stimulation (EPS), as a non-pharmacological, non-surgical, and non-invasive physical therapy, avoids the risks of infection, material costs, bacterial resistance, and patient tolerance associated with traditional methods. For oral soft tissue inflammation, EPS exerts its anti-inflammatory effect by modulating the immune inflammatory response, inhibiting excessive neutrophil infiltration, and promoting macrophage polarization towards the repair type (M2 type). Its specific mechanism of action involves downregulating the TLR2 / 4-NF-κB pathway in gingival epithelial cells and macrophages, reducing the release of TNF-α, IL-1β, and IL-6, and inhibiting excessive macrophage activation; simultaneously, it activates the cholinergic anti-inflammatory pathway, upregulates the anti-inflammatory factor (IL-10), and promotes inflammation resolution.

[0005] For intraoral hard tissue bone repair, electric field stimulation, by simulating the natural electrical signals generated by bone under physiological load, regulates cell behavior and molecular pathways. It also possesses a "bidirectional regulatory" characteristic, promoting osteogenic formation and inhibiting osteoclastization, demonstrating unique advantages in bone defect repair, bone integration, and bone regeneration. Furthermore, this treatment method is suitable for various pathological conditions, such as osteoporosis and diabetes. Currently, mainstream clinical electrotherapy equipment is complex, with bulky and inconvenient external power supply outputs, and limited applicability to specific models. Moreover, the electrodes are mostly rigid, unable to conform to the wound, revealing certain problems in terms of the flexibility of electric field design and patient comfort. Utilizing the dynamic pressure of tooth occlusion in the oral cavity, combined with transducers, can serve as a self-powered unit. Electrodes can be wired to the damaged area requiring intervention and integrated into wearable braces, which can be considered a solution. However, when piezoelectric materials are subjected to repeated application and release of tooth occlusal forces on the brace surface, they cannot recover their deformation in time, leading to unstable electrical signal output. Summary of the Invention

[0006] The purpose of this invention is to provide a flexible magnetically modified wearable piezoelectric restorative dental crown, which is low in cost, highly practical, stable, comfortable, customizable, has a stable manufacturing process, and is easy to prepare, thus facilitating large-scale industrial production.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A flexible, magnetically modified, wearable piezoelectric restorative dental crown includes a flexible carrier and a functional composite layer. The flexible carrier serves as a substrate, and the functional composite layer is disposed on the flexible carrier. The functional composite layer comprises, from top to bottom, a first PU encapsulation layer, a first magnetic film modification layer, a piezoelectric functional layer, a second magnetic film modification layer, and a second PU encapsulation layer.

[0009] Both the first PU encapsulation layer and the second PU encapsulation layer are made of polyurethane film;

[0010] The first magnetic thin film modification layer and the second magnetic thin film modification layer are magnetized along their thickness direction, and their magnetic moments are arranged in antiparallel order, so that the lower surface of the first magnetic thin film modification layer and the upper surface of the second magnetic thin film modification layer have the same magnetic poles.

[0011] The piezoelectric functional layer includes a first aluminum film electrode, a polyvinylidene fluoride piezoelectric material layer, and a second aluminum film electrode layer arranged sequentially from bottom to top.

[0012] Furthermore, the piezoelectric functional layer is an integrated double-rotation structure or a paper-cut structure, where the first aluminum film electrode, the piezoelectric material layer, and the second aluminum film electrode layer are treated as a whole and laser-cut to obtain the target structure. In practical applications, this structure can be matched with different tensile properties according to parameters such as the expected occlusal pressure range, target output voltage value, and effective area. This ensures that the inner piezoelectric material does not break under complex deformations such as braces occlusion, and that the outer first and second aluminum film electrode layers maintain continuous conductivity. This is suitable for stable voltage output over large areas and even more beneficial for effective voltage output over small areas.

[0013] Furthermore, the thickness of the piezoelectric functional layer is 20-40 micrometers.

[0014] Furthermore, the thickness of the first magnetic thin film modification layer is 100 μm, and the thickness of the second magnetic thin film modification layer is 100-300 μm.

[0015] Furthermore, both the first and second magnetic thin film modification layers are made of NdFeB-doped elastic matrix composite materials; wherein, under the premise of fixed NdFeB doping amount, the saturation magnetization of the prepared film is positively correlated with the thickness.

[0016] Furthermore, a periodic array of micro pyramid structures is prepared on the contact surface between the second magnetic thin film modification layer and the piezoelectric functional layer using a template method; the template method is preferably nanoimprinting.

[0017] Furthermore, the preparation method of the first magnetic thin film modification layer and the second magnetic thin film modification layer materials includes:

[0018] 1) Using n-heptane or toluene as a co-solvent, NdFeB particles are mixed at a mass ratio of co-solvent:NdFeB = 1:5 to form a first mixed solution;

[0019] 2) The first mixed solution is mixed evenly with PDMS solution A and solution B to obtain a second mixed solution, wherein the ratio of PDMS solution A: PDMS solution B: NdFeB is 10: 1: 50;

[0020] 3) Take 2 mL of the second mixed solution and place it on a 7.5 cm × 7.5 cm glass substrate. Form a film by spin coating or blade coating. Finally, heat and cure at 60°C or higher and remove the film.

[0021] 4) Place the substrate obtained in step 3) on a heating table at 60°C and heat until fully cured, then demold. To improve efficiency, in this embodiment, the temperature is increased to 70°C after initial shaping to accelerate the subsequent curing process.

[0022] This invention provides a flexible, magnetically modified wearable piezoelectric restorative brace. The flexible carrier is the wearable brace body, and the functional composite layer integrates piezoelectric and magnetic functions. The overall thickness is less than 400 micrometers, reducing the negative impacts of excessively thick braces, such as occlusal disorders. NdFeB is a hard magnetic material with high coercivity and strong resistance to demagnetization, and it has high remanence, retaining its magnetism even after the removal of an external magnetic field. Doping NdFeB into organic elastomers allows the material to possess both flexibility and magnetism. Magnetizing the magnetic thin film creates a mutually repulsive structure, which helps shorten the stress application time and accelerate strain recovery, thereby improving the durability and stability of the piezoelectric material. A periodic micro-pyramid structure array is prepared on the contact surface between the second magnetic thin film modification layer and the piezoelectric functional layer using a template method, which increases strain and thus enhances the voltage output effect. In other words, the second magnetic thin film modification layer significantly improves the output performance of the piezoelectric thin film and effectively enhances its long-term stability. The surface of dental braces is uneven. The piezoelectric functional layer employs an integrated double-spindle structure or a paper-cut structure. This allows the components to adhere uniformly to the braces surface and ensures that the components do not fail under dynamic pressure. When external stress is applied to the polyvinylidene fluoride (PVDF) film, the material deforms, the internal dipoles deflect, and the polarization intensity changes. Surface charges are induced on the electrodes on the upper and lower surfaces of the material, and transmitted via wires to flexible interdigital electrodes, covering the damaged tissue area to implement electric field intervention therapy.

[0023] Compared with existing technologies, the wearable piezoelectric restorative dental aligner of this invention relies on a flexible wearable dental aligner body and uses electric field stimulation as a physical therapy to achieve non-invasive tissue repair. Therefore, it is suitable for various oral disease models, including soft tissues in the oral cavity, such as gingivitis and periodontal tissue inflammation reduction, and hard tissues, such as alveolar bone repair after tooth extraction. Its piezoelectric functional layer can be adjusted according to the actual application scenario, comprehensively adjusting parameters such as the occlusal pressure range, flexible structure design, and effective area to achieve the target output voltage value, supporting personalized customization. The stability of the piezoelectric device is improved by introducing a magnetic thin film mutual repulsion layer. Attached Figure Description

[0024] Figure 1 A schematic diagram of the layered structure of the flexible magnetically modified wearable piezoelectric restorative dental crown provided in the embodiment;

[0025] Figure 2 A flowchart illustrating the fabrication process of the flexible magnetically modified wearable piezoelectric restorative dental crown provided in this embodiment;

[0026] Figure 3 A flowchart illustrating the fabrication process of the pyramid-shaped microstructure magnetic thin film provided in this embodiment;

[0027] Figure 4The following are actual images of the flexible magnetic modified wearable piezoelectric restorative dental crown provided in the embodiment: a is a three-dimensional image of a double-rotation high-stretch piezoelectric structure suitable for inflammation models attached to the dental crown; b is a three-dimensional image of a high-density paper-cut structure suitable for toothless models attached to the dental crown.

[0028] Figure 5 Scanning electron microscope images of the NdFeB magnetic thin film provided in the embodiments; where a is a top view and b is a side view;

[0029] Figure 6 The stress-strain curves for the embodiment;

[0030] Figure 7 The following are voltage output diagrams for an example under different tensile strains;

[0031] Figure 8 The voltage output diagram is shown for an example under different pressures. Detailed Implementation

[0032] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0033] like Figure 1 As shown, this embodiment provides a flexible magnetically modified wearable piezoelectric restorative dental crown, including a flexible carrier and a functional composite layer. The flexible carrier serves as a substrate, and the functional composite layer is disposed on the flexible carrier. The functional composite layer includes, from top to bottom, a first PU encapsulation layer, a first magnetic film modification layer, a piezoelectric functional layer, a second magnetic film modification layer, and a second PU encapsulation layer; wherein:

[0034] Both the first PU encapsulation layer and the second PU encapsulation layer are made of polyurethane film;

[0035] The first and second magnetic thin film modification layers are magnetized along their thickness direction, and their magnetic moments are antiparallel, so that the lower surface of the first magnetic thin film modification layer and the upper surface of the second magnetic thin film modification layer have the same magnetic poles. In this embodiment, the thickness of the first magnetic thin film modification layer is 100 μm, and the thickness of the second magnetic thin film modification layer is 100-300 μm. The materials of both the first and second magnetic thin film modification layers are NdFeB-doped elastic matrix composite materials; wherein, under the premise of a fixed NdFeB doping amount, the saturation magnetization of the prepared film is positively correlated with the thickness. A periodic micro pyramid structure array is constructed on the second magnetic thin film modification layer using nanoimprinting. Figure 3 As shown, the preparation method of the first magnetic thin film modification layer and the second magnetic thin film modification layer materials includes:

[0036] 1) Using n-heptane or toluene as a co-solvent, NdFeB particles are mixed at a mass ratio of co-solvent:NdFeB = 1:5 to form a first mixed solution;

[0037] 2) The first mixed solution is mixed evenly with PDMS solution A and solution B to obtain a second mixed solution, wherein the ratio of PDMS solution A: PDMS solution B: NdFeB is 10: 1: 50;

[0038] 3) Take 2 mL of the second mixed solution and place it on a 7.5 cm × 7.5 cm glass substrate. Form a film by spin coating or blade coating. Finally, heat and cure at 60°C or higher and remove the film.

[0039] 4) Place the substrate obtained in step 3) on a heating table at 60°C and heat until fully cured, then demold. To improve efficiency, this embodiment increases the temperature after initial shaping to accelerate the subsequent curing process. The piezoelectric functional layer includes a first aluminum film electrode, a polyvinylidene fluoride piezoelectric material layer, and a second aluminum film electrode layer arranged sequentially from bottom to top. The thickness of the piezoelectric functional layer in this embodiment is 20-40 micrometers. In this embodiment, the piezoelectric functional layer adopts an integrated double-spindle structure or a paper-cut structure, that is, the first aluminum film electrode, the piezoelectric material layer, and the second aluminum film electrode layer are laser-cut into a flexible structure as a whole. The design of this integrated double-spindle structure or paper-cut structure can be customized according to parameters such as expected occlusal pressure, target output voltage, and effective area to match different tensile properties. This ensures that the inner piezoelectric material does not break under complex deformations such as braces occlusion, and the outer first and second aluminum film electrode layers can maintain continuous conductivity, thereby simultaneously taking into account voltage output over a large area and effective voltage acquisition over a small area. During use, the cycle of applying and releasing the biting force of the teeth induces opposite charges on the upper and lower surface electrodes of the piezoelectric functional layer. At the same time, the magnetic thin film modification layer promotes the recovery of mechanical strain through magnetic repulsion. This not only ensures the stable generation of charges but also enables them to be efficiently transmitted to the flexible interdigital electrodes covering the damaged tissue area, ultimately achieving electric field intervention therapy.

[0040] The flexible carrier used in this embodiment of the flexible magnetic-modified wearable piezoelectric restorative dental crown can be an existing wearable device. It includes a crown carrier and a regional electric field restoration module. The crown carrier is made by heating and vacuum forming a model resin placed above a plaster model. The regional electric field restoration module includes a third PU encapsulation layer, an interdigital electrode layer, and a fourth PU encapsulation layer. The interdigital electrode material is copper foil with a thickness of 10-30 micrometers. In this embodiment, the functional composite layer in the crown serves as a piezoelectric conversion module, which is fixed together with the regional electric field restoration module within the crown carrier. The dual-rotation structure in this embodiment is a planar vortex rotation structure, exhibiting a spiral shape that gradually extends outward from the central region, resembling multiple continuous and gradually expanding "vortices" encircling each other. The whole structure is formed by curling a strip-shaped portion with a width of d. From the center outward, the spiral contour range gradually expands from the size R to the maximum span L. The spiral coils are relatively evenly distributed, forming a symmetrical planar vortex rotation structure.

[0041] Figure 2 The fabrication process of the flexible magnetically modified wearable piezoelectric restorative dental crown of this embodiment is demonstrated. The specific operation steps are as follows:

[0042] Both the piezoelectric functional layer and the interdigital electrode layer are patterned using an ultraviolet nanosecond laser cutting machine. First, a layer of single-sided hydrosol is fixed on the bottom surface of the material. Then, it is cut to complete peeling under the corresponding laser parameters. After peeling off the complementary part of the specified pattern, the interdigital electrode layer is encapsulated with PU on the top layer. Then, the hydrosol is washed away with water, and the bottom layer is encapsulated with PU again.

[0043] A PDMS solution doped with magnetic particles was spin-coated or blade-coated onto the surface of the piezoelectric functional layer to form a tightly bonded piezoelectric functional layer and first magnetic film composite. The entire composite was then laser-cut with the following parameters: a power factor of 50%, a scanning speed of 1000 mm / s, and 160 layers. For the laser cutting of a single piezoelectric functional layer, the power factor was adjusted to 40% and the number of layers was 130. A 20 μm copper foil was selected as the interdigital electrode material, and the cutting parameters were adjusted to a power factor of 70% and 50 layers.

[0044] Figure 4 This is a photograph of a wearable piezoelectric restorative dental brace with flexible magnetic modification, as shown in the embodiment. Figure 4 As can be seen, this example is applicable to various oral disease models, including soft tissues in the oral cavity, such as the resolution of periodontal inflammation in gingivitis (see...). Figure 4 a) and hard tissues such as alveolar bone repair after tooth extraction (see Figure 4 (b) In this context, the device can be uniformly attached to the inner surface of the braces through a flexible structure design.

[0045] Figure 5 This is a scanning electron microscope image of the second magnetic thin film in Example 2. Figure 5 a and Figure 5 As can be seen from b, NdFeB is uniformly dispersed in PDMS. The resulting microstructured magnetic film has a uniform and complete pyramid distribution with a side length of 50 μm, a height of 35 μm, and a spacing of 20 μm.

[0046] Figure 6 The stress-strain curves are from an example. Figure 6 It can be seen from the stress-strain curves of the device after three repeated tests that the double-rotation piezoelectric structure fractured at a strain of nearly 220%, with a tensile strength of approximately 1.5 MPa.

[0047] Figure 7 The diagram shows the voltage output under different tensile strains in the example. Figure 7 It can be seen that before the strength failure, the voltage in this embodiment increases with the increase of tensile strain, and the dual-rotation piezoelectric structure can maintain a stable voltage output under 72% tensile strain.

[0048] Figure 8 The diagram shows the voltage output under different pressures in the example. Figure 8 It can be seen that as the pressure increases, the voltage increases linearly, and the target voltage can be achieved by combining the force, the area of ​​action, and the spacing between the interdigitated electrodes.

Claims

1. A flexible magnetically modified wearable piezoelectric restorative dental crown, comprising a flexible carrier and a functional composite layer, wherein the flexible carrier serves as a substrate and the functional composite layer is disposed on the flexible carrier; characterized in that, The functional composite layer comprises, from top to bottom, a first PU encapsulation layer, a first magnetic thin film modification layer, a piezoelectric functional layer, a second magnetic thin film modification layer, and a second PU encapsulation layer; wherein: Both the first PU encapsulation layer and the second PU encapsulation layer are made of polyurethane film; The first magnetic thin film modification layer and the second magnetic thin film modification layer are magnetized along their thickness direction, and their magnetic moments are arranged in antiparallel order, so that the lower surface of the first magnetic thin film modification layer and the upper surface of the second magnetic thin film modification layer have the same magnetic poles. The piezoelectric functional layer includes a first aluminum film electrode, a polyvinylidene fluoride piezoelectric material layer, and a second aluminum film electrode layer arranged sequentially from bottom to top.

2. The flexible magnetically modified wearable piezoelectric restorative dental brace according to claim 1, characterized in that, The piezoelectric functional layer is an integrated double-rotation structure or a paper-cut structure, that is, the first aluminum film electrode, the piezoelectric material layer and the second aluminum film electrode layer are laser-cut as a whole to obtain the target structure.

3. The flexible magnetically modified wearable piezoelectric restorative dental brace according to claim 1, characterized in that, The thickness of the piezoelectric functional layer is 20-40 micrometers.

4. The flexible magnetically modified wearable piezoelectric restorative dental brace according to claim 1, characterized in that, The thickness of the first magnetic thin film modification layer is 100 μm, and the thickness of the second magnetic thin film modification layer is 100-300 μm.

5. The flexible magnetically modified wearable piezoelectric restorative dental brace according to claim 1, characterized in that, The first and second magnetic thin film modification layers are both made of NdFeB-doped elastic matrix composite materials; wherein, under the premise of fixed NdFeB doping amount, the saturation magnetization of the prepared film is positively correlated with the thickness.

6. The flexible magnetically modified wearable piezoelectric restorative dental brace according to claim 1, characterized in that, A periodic array of micro pyramid structures is constructed on the second magnetic thin film modification layer using nanoimprinting.

7. The flexible magnetically modified wearable piezoelectric restorative dental brace according to claim 6, characterized in that, The preparation methods of the first magnetic thin film modification layer and the second magnetic thin film modification layer materials include: 1) Using n-heptane or toluene as a co-solvent, NdFeB particles are mixed at a mass ratio of co-solvent:NdFeB = 1:5 to form a first mixed solution; 2) The first mixed solution is mixed evenly with PDMS solution A and solution B to obtain a second mixed solution, wherein the ratio of PDMS solution A:PDMS solution B:NdFeB is 10:1:50; 3) Take 2 mL of the second mixed solution and place it on a 7.5 cm × 7.5 cm glass substrate. Form a film by spin coating or blade coating. Finally, heat to 60°C or higher to cure and remove the film. 4). Place the substrate obtained in step 3) on a heating table at 60°C and heat until it is completely cured, then demold it.

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