Thin film sensor detection device for tooth adjacent surface contact area

Abstract

The invention belongs to the technical field of tooth adjacent surface contact area detection, and particularly discloses a tooth adjacent surface contact area thin film sensor detection device which comprises a thin film pressure sensor module, a data acquisition module, a signal processing module, a display module and a data storage and transmission module. The signal processing module is respectively connected with the data acquisition module, the display module and the data storage and transmission module; the thin film pressure sensor module is of an array structure composed of a plurality of sub-sensors, and each sub-sensor has a unique position code and is used for collecting pressure signals of a tooth adjacent surface contact area and outputting resistance change signals with position information. The problems that an existing sensor array cannot form a high-precision shape contour, cannot be spliced into a continuously measurable contact shape and cannot output shape parameters of a tooth adjacent surface contact area, and the requirements of orthodontics, repair and the like for accurate design of the adjacent surface contact shape are difficult to meet are solved.

Description

Technical Field

[0001] This invention belongs to the field of dental proximal contact area detection technology, specifically relating to a thin-film sensor detection device for dental proximal contact area. Background Technology

[0002] Normal tooth contact is crucial for oral health. The morphology, tightness, contact area, and force distribution of the proximal contact area are important indicators for orthodontic, restorative, occlusal reconstruction, and periodontal health assessment. Parameters such as tightness, location, shape, and area are commonly used quantitative indicators for assessing the proximal contact area. Currently, clinical practice primarily relies on qualitative assessment of tightness.

[0003] Dental floss is the most commonly used method for clinically assessing interproximal contact tightness. However, this method is considered highly subjective and unstable, cannot be quantified, and the quantitative equipment is too complex, limiting its intraoral application. Metal strips are another method for clinically assessing interproximal contact tightness. However, the definition of metal strip thickness for this method is still controversial and cannot be accurately quantified. Currently, clinical and research assessments of interproximal contact status primarily rely on pressure detection, which makes it difficult to directly and accurately obtain the two-dimensional or three-dimensional morphological contours of the interproximal contact area. There are existing solutions using sensors to detect force on the interproximal contact area, with the core objective of obtaining the overall contact pressure magnitude. These traditional sensors have the following shortcomings: insufficient sensor array density, failing to form a high-precision morphological contour; lack of independent position encoding and coordinate mapping mechanisms, only pressure cloud maps can be obtained, which cannot be pieced together into a continuous, measurable contact morphology; and the inability to output morphological parameters such as the shape, boundary, area, aspect ratio, and contact point location of the interproximal contact area, making it difficult to meet the needs of orthodontic and restorative procedures for precise design of interproximal contact morphology. Summary of the Invention

[0004] The purpose of this invention is to solve the problems that existing sensor arrays cannot form high-precision morphological contours, cannot be spliced ​​into continuous measurable contact morphologies, and cannot output morphological parameters of the proximal contact area of ​​teeth, making it difficult to meet the needs of orthodontics, prosthodontics, and other fields for precise design of proximal contact morphology. A thin-film sensor detection device for the proximal contact area of ​​teeth is proposed.

[0005] The technical solution of the present invention is as follows: a thin-film sensor detection device for the contact area of ​​the proximal surface of teeth, comprising a thin-film pressure sensor module, a data acquisition module, a signal processing module, a display module, a data storage and transmission module, and a power supply module. The thin-film pressure sensor module is connected to the data acquisition module, the signal processing module is connected to the data acquisition module, the display module, and the data storage and transmission module, and the power supply module is connected to the thin-film pressure sensor module, the data acquisition module, the signal processing module, the display module, and the data storage and transmission module. The thin-film pressure sensor module is an array structure composed of multiple sub-sensors. Each sub-sensor has a unique position code and is used to collect pressure signals in the contact area of ​​the proximal surfaces of teeth and output resistance change signals with position information. The data acquisition module is used to acquire the resistance change signals of each sub-sensor; The signal processing module is used to convert resistance change signals into pressure values ​​and calculate the area and morphological parameters of the contact area based on position encoding to generate a two-dimensional morphological profile of the tooth proximal contact area. The display module is used to visually display the two-dimensional shape outline and shape parameters; The data storage and transmission module is used to store historical detection data and transmit it to external terminal devices; The power supply module is used to power all modules.

[0006] Preferably, the thin-film pressure sensor module is a 1cm×1cm square structure, consisting of 400 sub-sensors arranged in a 20×20 array, with a center-to-center distance of 0.5mm between adjacent sub-sensors.

[0007] Preferably, each sub-sensor has a three-layer composite structure, with the upper and lower layers being 0.008mm thick polyethylene terephthalate (PET) sheets; and the middle layer being a 0.008mm thick high-temperature resistant carbon paste layer.

[0008] Preferably, the resistance of the high-temperature resistant carbon paste layer changes with the pressure applied to the sub-sensor. The high-temperature resistant carbon paste layer is surrounded by a silver conductor, and the silver conductor is connected to a wire leading out to the electrode, which is used to transmit the resistance change signal to the data acquisition module.

[0009] As a preferred option, the formula for calculating the pressure value is:

[0010] in, Indicates the first Individual sensor pressure value, Represents the sensitivity coefficient. This represents the change in resistance. This indicates the zero-pressure offset.

[0011] As a preferred method, the specific approach for generating the two-dimensional morphological contour of the tooth proximal contact area based on calculating the area and morphological parameters of the contact area using position encoding is as follows: Calculate the center coordinates of each sub-sensor in the preset coordinate system based on the position code of each sub-sensor; The center coordinates of sub-sensors with pressure values ​​greater than or equal to a preset threshold are marked as effective contact points, forming a set of effective points; The effective point set is denoised by removing outliers that are more than twice the standard deviation away from the mean point, resulting in a cleaned point set. The convex hull algorithm is used to extract the boundaries of the cleaned point set to obtain the boundary point set; Based on the boundary point set, the contact area and morphological parameters are calculated to complete the two-dimensional morphological contour reconstruction of the contact area of ​​the proximal surface of the tooth.

[0012] As a preferred method, the effective point set is denoised by removing outliers that are more than twice the standard deviation away from the mean point, resulting in a cleaned point set. Calculate the mean coordinates of the effective point set :

[0013] in, This indicates the total number of effective contact points. Indicates the first The x-coordinate of each effective contact point Indicates the first The ordinate of each effective contact point; Calculate the Euclidean distance from each effective contact point to the mean coordinate. :

[0014] Points with a distance greater than twice the standard deviation are removed to obtain the cleaned point set.

[0015] As a preferred method, the convex hull algorithm is used to extract the boundary of the cleaned point set. The specific method for obtaining the boundary point set is as follows: Arrange the cleaned point sets in ascending order of their horizontal coordinates; Calculate the cross product of the vectors between the three points in order of arrangement. If the cross product is less than or equal to 0, remove the points that are inside the three points. If the cross product is greater than 0, keep all the points and traverse the sorted points in the forward direction to complete the construction of the lower convex hull. Traverse the sorted points in reverse order, calculate the cross product of vectors, and construct the upper convex hull; Remove the duplicate endpoints of the lower and upper convex shells, and merge the upper and lower convex shells to obtain the complete set of boundary points of the contact area.

[0016] As a preferred option, the contact area area The calculation formula is:

[0017] in, Indicates the contact area number The x-coordinates of the boundary points Indicates the contact area number The ordinates of the boundary points Indicates the contact area number The x-coordinates of the boundary points Indicates the contact area number The ordinates of the boundary points.

[0018] Preferably, the morphological parameters include the major axis, minor axis, eccentricity, and center coordinates.

[0019] The beneficial effects of this invention are: 1. This invention upgrades pressure measurement to morphology measurement through high-density arrays and position markers, achieving morphology detection and quantification for the first time.

[0020] 2. The high-density array design proposed in this invention uses a 20×20 sub-sensor module to achieve high-resolution sampling within a 1cm×1cm range, ensuring morphological accuracy.

[0021] 3. This invention incorporates position marking and coordinate reconstruction. Each sensor carries a unique position code, and the contact area outline is directly pieced together from the set of coordinate points, rather than simply displaying the overall pressure value.

[0022] 4. This invention can output morphological parameters. It can output morphological indicators such as the shape, area, boundary, and size of the contact area, providing direct data support for enamel removal from adjacent surfaces, restoration morphology design, and orthodontic adjacent surface control. Attached Figure Description

[0023] Figure 1 The diagram shows a structural diagram of a thin-film sensor detection device for the contact area of ​​a tooth proximal surface.

[0024] Figure 2 The diagram shown is a detailed structural diagram of the thin-film pressure sensor module.

[0025] Figure 3 The diagram shown is a structural diagram of the sub-sensor.

[0026] Explanation of reference numerals in the attached diagram: 1. Thin-film pressure sensor module; 2. Data acquisition module; 3. Signal processing module; 4. Display module; 5. Data storage and transmission module; 6. Power supply module. Detailed Implementation

[0027] Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the embodiments shown and described in the drawings are merely exemplary and are intended to illustrate the principles and spirit of the invention, and are not intended to limit the scope of the invention.

[0028] Example 1: like Figure 1As shown, a thin-film sensor detection device for the proximal contact area of ​​teeth includes a thin-film pressure sensor module 1, a data acquisition module 2, a signal processing module 3, a display module 4, a data storage and transmission module 5, and a power supply module 6. The output terminal of the thin-film pressure sensor module 1 is connected to the data acquisition module 2, the data acquisition module 2 is connected to the signal processing module 3, the signal processing module 3 is connected to the display module 4 and the data storage and transmission module 5 respectively, and the power supply module 6 is connected to the thin-film pressure sensor module 1, the data acquisition module 2, the signal processing module 3, the display module 4 and the data storage and transmission module 5 to supply power to all modules.

[0029] The thin-film pressure sensor module 1 is a square with a length and width of 1cm, consisting of 400 sub-sensor modules arranged in a 20×20 array, as shown below. Figure 2 As shown. Each sub-sensor module consists of three layers: the top and bottom layers are 0.008mm thick polyethylene terephthalate sheets, the middle layer is a 0.008mm thick high-temperature resistant carbon paste layer, and the carbon paste layer is surrounded by silver conductors, connecting wires and leading out electrodes, as shown. Figure 3 As shown, each sub-sensor module corresponds to a set of row and column coordinates (row i, column j) as position markers. When the sensor is subjected to pressure, the resistance of the carbon paste layer changes. The raw resistance data of each area collected by the wire is transmitted to the data acquisition module 2, processed by the signal processing module 3, and outputs the coordinate position and contact pressure signal value. Through coordinate point set fitting, boundary extraction, and area calculation, the true morphology of the contact area of ​​the tooth proximal surface is directly restored. The data storage and transmission module 5 is used for local data storage.

[0030] The thin-film pressure sensor module 1 is placed in the contact area of ​​the proximal surface of the tooth to be tested; when pressure is naturally generated in the contact area, the resistance of the carbon paste layer 30 changes with the pressure; the data acquisition module 2 acquires multiple resistance signals; the signal processing module 3 performs calibration and calculation to obtain the pressure and coordinates of each point; the display module 4 displays the proximal surface contact morphology and pressure value in a graphical manner; the data storage and transmission module 5 saves the records and can export them.

[0031] In this embodiment, the sub-sensor pressure value is calculated as follows: the signal processing module 3 converts the resistance change into a pressure value based on a preset resistance-pressure calibration relationship. The specific formula is: P i =k×ΔR i +b(P) i Let ΔR be the pressure value of the i-th sub-sensor. i (where k is the resistance change, k is the sensitivity coefficient, and b is the zero-voltage offset).

[0032] In this embodiment, the specific acquisition process of the data acquisition module 2 is as follows: initial calibration, the thin film is placed in the air, and the zero-point offset is calibrated. If an abnormality is detected, it prompts to replace the probe or re-calibrate; data acquisition must be performed in a normal humidified environment in the oral cavity; after calibration, the thin film pressure sensor module 1 is placed in the interdental space contact area, so that the contact area is located in the central area of ​​the thin film pressure sensor module 1, and then data acquisition begins, sampling is performed according to the preset sampling frequency.

[0033] In this embodiment, the signal processing module 3 performs calibration and calculation to obtain the pressure and coordinates of each point as follows: S1. Constructing the basic coordinate system The sensing device is a 1cm × 1cm square, corresponding to the coordinate range: X-axis (column) 0-1cm, Y-axis (row) 0-1cm. A 20×20 sub-sensor array is used, with the center coordinates of each sensor being: the center coordinates of the sensor in the i-th row and j-th column (i,j∈[1,20]): X... j =(j 1)×0.05+0.025(cm), Y i =(i 1) × 0.05 + 0.025 (cm). Define "effective contact point": The pressure value detected by the sensor ≥ a set threshold (e.g., minimum contact pressure P0), denoted as the point set S = {(x1,y1), (x2,y2),..., (x... n ,y n )}, n≤400; S2. Coordinate point set preprocessing (denoising, normalization) Calculate the mean coordinates of the point set S :

[0034] Calculate the Euclidean distance from each point to the mean coordinate point. :

[0035] Remove points that are more than twice the standard deviation away (outliers): .

[0036] Point set normalization: retain the effective point set after cleaning. :

[0037] S3. Boundary Extraction Sort the point set: Sort the valid point set Sort by x-coordinate in ascending order; if x-coordinates are the same, sort by y-coordinate in ascending order. Construct a lower convex hull: Given three points A (x1, y1), B (x2, y2), and C (x3, y3), calculate the cross product of the vectors:

[0038] If the result is ≤0, it means that point B is inside AC and needs to be eliminated; Constructing the upper convex hull: Traverse the sorted points in reverse order and repeat the lower convex hull construction logic; Merging convex hulls: Removing duplicate endpoints from the upper and lower convex hulls yields the boundary point set B = {(x b1 ,y b1 ), (x b2 , y b2 ),..., (x bk ,y bk Sort by clockwise / counterclockwise.

[0039] S4. Area Calculation Based on the extracted boundary point set B, the contact area is calculated. :

[0040] in, , (Closed), the absolute value guarantees that the area is positive.

[0041] S5. Morphological Parameter Expansion Calculate the core morphological parameters based on the boundary and area: Major and minor axes: Perform principal component analysis (PCA) on the boundary point set. The direction of the first principal component is the major axis with a length L = 2 × √λ1, and the direction of the second principal component is the minor axis with a length W = 2 × √λ2, where λ1 represents the first eigenvalue and λ2 represents the second eigenvalue.

[0042] Eccentricity: (This reflects whether the contact area is elliptical) Center coordinates: (Geometric center of the contact area).

[0043] The thin-film sensor detection device for the interproximal contact area of ​​the present invention is used for non-invasive, quantitative, real-time pressure and morphology detection of the interproximal contact area of ​​teeth.

[0044] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A thin-film sensor detection device for the contact area of ​​proximal surfaces of teeth, characterized in that, It includes a thin-film pressure sensor module (1), a data acquisition module (2), a signal processing module (3), a display module (4), a data storage and transmission module (5), and a power supply module (6). The thin-film pressure sensor module (1) is connected to the data acquisition module (2). The signal processing module (3) is connected to the data acquisition module (2), the display module (4), and the data storage and transmission module (5) respectively. The power supply module (6) is connected to the thin-film pressure sensor module (1), the data acquisition module (2), the signal processing module (3), the display module (4), and the data storage and transmission module (5). The thin-film pressure sensor module (1) is an array structure composed of multiple sub-sensors. Each sub-sensor has a unique position code, which is used to collect the pressure signal of the contact area between the teeth and output the resistance change signal with position information. The data acquisition module (2) is used to acquire the resistance change signals of each sub-sensor; The signal processing module (3) is used to convert the resistance change signal into a pressure value and calculate the area and morphological parameters of the contact area based on the position encoding to generate a two-dimensional morphological profile of the tooth proximal contact area. Display module (4) is used to visually display the two-dimensional shape outline and shape parameters; The data storage and transmission module (5) is used to store historical detection data and transmit the data to external terminal devices; The power supply module (6) is used to power all modules.

2. The thin-film sensor detection device for the proximal contact area of ​​teeth according to claim 1, characterized in that, The thin-film pressure sensor module (1) is a square structure of 1cm×1cm, consisting of 400 sub-sensors arranged in a 20×20 array, with a center-to-center distance of 0.5mm between adjacent sub-sensors.

3. The thin-film sensor detection device for the proximal contact area of ​​teeth according to claim 1, characterized in that, Each sub-sensor has a three-layer composite structure. The upper and lower layers are both 0.008mm thick polyethylene terephthalate (PET) sheets; the middle layer is a 0.008mm thick high-temperature resistant carbon paste layer.

4. The thin-film sensor detection device for the proximal contact area of ​​teeth according to claim 3, characterized in that, The resistance of the high-temperature resistant carbon paste layer changes with the pressure applied to the sub-sensor. The high-temperature resistant carbon paste layer is surrounded by silver conductors, and the silver conductors are connected to lead out electrodes to transmit the resistance change signal to the data acquisition module (2).

5. The thin-film sensor detection device for the proximal contact area of ​​teeth according to claim 3, characterized in that, The formula for calculating the pressure value is: in, Indicates the first Individual sensor pressure value, Represents the sensitivity coefficient. This represents the change in resistance. This indicates the zero-pressure offset.

6. The thin-film sensor detection device for the proximal contact area of ​​teeth according to claim 1, characterized in that, The method for generating a two-dimensional morphological contour of the proximal contact area of ​​teeth based on location encoding to calculate the area and morphological parameters of the contact area is as follows: Calculate the center coordinates of each sub-sensor in the preset coordinate system based on the position code of each sub-sensor; The center coordinates of sub-sensors with pressure values ​​greater than or equal to a preset threshold are marked as effective contact points, forming a set of effective points; The effective point set is denoised by removing outliers that are more than twice the standard deviation away from the mean point, resulting in a cleaned point set. The convex hull algorithm is used to extract the boundaries of the cleaned point set to obtain the boundary point set; Based on the boundary point set, the contact area and morphological parameters are calculated to complete the two-dimensional morphological contour reconstruction of the contact area of ​​the proximal surface of the tooth.

7. The thin-film sensor detection device for the proximal contact area of ​​teeth according to claim 6, characterized in that, The method for denoising the valid point set and removing outliers that are more than twice the standard deviation from the mean point to obtain the cleaned point set is as follows: Calculate the mean coordinates of the effective point set : in, This indicates the total number of effective contact points. Indicates the first The x-coordinate of each effective contact point Indicates the first The ordinate of each effective contact point; Calculate the Euclidean distance from each effective contact point to the mean coordinate. : Points with a distance greater than twice the standard deviation are removed to obtain the cleaned point set.

8. The thin-film sensor detection device for the proximal contact area of ​​teeth according to claim 6, characterized in that, The convex hull algorithm is used to extract the boundaries of the cleaned point set, and the specific method for obtaining the boundary point set is as follows: Arrange the cleaned point sets in ascending order of their horizontal coordinates; Calculate the cross product of the vectors between the three points in order of arrangement. If the cross product is less than or equal to 0, remove the points that are inside the three points. If the cross product is greater than 0, keep all the points and traverse the sorted points in the forward direction to complete the construction of the lower convex hull. Traverse the sorted points in reverse order, calculate the cross product of vectors, and construct the upper convex hull; Remove the duplicate endpoints of the lower and upper convex shells, and merge the upper and lower convex shells to obtain the complete set of boundary points of the contact area.

9. The thin-film sensor detection device for the proximal contact area of ​​teeth according to claim 8, characterized in that, Contact area The calculation formula is: in, Indicates the contact area number The x-coordinates of the boundary points Indicates the contact area number The ordinates of the boundary points Indicates the contact area number The x-coordinates of the boundary points Indicates the contact area number The ordinates of the boundary points.

10. The thin-film sensor detection device for the proximal contact area of ​​teeth according to claim 1, characterized in that, The morphological parameters include the major axis, minor axis, eccentricity, and center coordinates.

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