Intraoral optical sensor

Abstract

This intraoral optical sensor is provided with an attachment tool that attaches to the gingiva inside of an oral cavity, and an optical sensor that is fixed to the attachment tool. The optical sensor is provided with at least one light-emitting element and a light-receiving element. In the optical sensor, the light-emitting element is disposed such that the light emitted from the light-emitting element is radiated onto the gingiva, and the light-emitting element is disposed so as to be in close contact with the surface of intraoral tissue such that a pulse wave or the blood oxygen saturation is measured.

Description

Intraoral optical sensor

[0001] The present invention relates to an intraoral optical sensor. This application claims priority to Japanese Patent Application No. 2023-144819, filed on September 6, 2023, the contents of which are incorporated herein by reference.

[0002] A physiological quantity detection device is known that is a reflective pulse oximeter sensor that measures blood oxygen saturation by irradiating the greater palatine artery with a light-emitting element, and is placed on a support base in close contact with the surface of the oral cavity (Patent Document 1).

[0003] Japanese Patent Application Publication No. 7-246191

[0004] In the physiological quantity detection device described in Patent Document 1, the light-emitting element is installed in the greater palatine artery, which has branches distributed throughout the upper jaw. In the physiological quantity detection device described in Patent Document 1, it is unclear which part of the upper jaw the light-emitting element should be installed in to stably measure the pulse wave or blood oxygen saturation. There is a demand for the ability to stably measure the pulse wave or blood oxygen saturation.

[0005] The present invention has been made in view of the above points, and provides an intraoral optical sensor that can stably measure pulse waves or blood oxygen saturation.

[0006] The present invention has been made to solve the above-mentioned problems, and one aspect of the present invention is an intraoral optical sensor that measures pulse waves or blood oxygen saturation, comprising an attachment device that is attached to the gums in the oral cavity, and an optical sensor fixed to the attachment device, wherein the optical sensor comprises one or more light-emitting elements and a light-receiving element, and the light-emitting elements are positioned so that light emitted from the light-emitting elements is irradiated onto the gums, and the light-emitting elements are positioned so that they are in close contact with the surface of oral tissue.

[0007] In addition, in one aspect of the present invention, in the above-mentioned intraoral optical sensor, the light receiving element receives reflected light that is generated when light emitted by the light emitting element is reflected by intraoral tissue.

[0008] In addition, one aspect of the present invention is the intraoral optical sensor, wherein the light-emitting element is placed on the gums of the upper jaw.

[0009] In another aspect of the present invention, in the intraoral optical sensor described above, the light-emitting element is installed on either the maxillary no. 1 palatal gingiva, the maxillary no. 2 palatal gingiva, or the maxillary no. 3 palatal gingiva.

[0010] In addition, in one aspect of the present invention, in the intraoral optical sensor, the light-emitting element is placed on the palatal gingiva of the maxillary third tooth.

[0011] In another aspect of the present invention, in the intraoral optical sensor, the light-emitting element is arranged so as to be in close contact with the surface of the oral cavity under a load of 0.3 N or more and 0.8 N or less.

[0012] In addition, one aspect of the present invention is that, in the above-mentioned intraoral optical sensor, the light-emitting element and the light-receiving element are sealed with a transparent resin consisting of two or more layers, the light-emitting element is in close contact with the intraoral surface via the resin, and the layer of the two or more layers of the resin that comes into contact with the intraoral surface is parylene.

[0013] In addition, one aspect of the present invention is the above-mentioned intraoral optical sensor, wherein the attachment is an intraoral device.

[0014] According to the present invention, pulse waves or blood oxygen saturation can be measured stably.

[0015] FIG. 1 is a diagram showing an example of the functional configuration of an intraoral optical sensor according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of a site of the maxillary gingiva according to an embodiment of the present invention. FIG. 3 is a diagram showing an example of the results of actual measurement of the perfusion index (PI value) at each site of the maxilla according to an embodiment of the present invention. FIG. 4 is a diagram showing an example of a graph showing the change in relative PI value with respect to the change in load on the light-emitting element according to an embodiment of the present invention. FIG. 5 is a diagram showing an example of the appearance of an intraoral optical sensor when a substrate according to an embodiment of the present invention is attached to a fixture. FIG. 6 is a diagram showing an example of a state in which the light-emitting element according to an embodiment of the present invention is fixed so as to be in close contact with the surface of the maxillary gingiva. FIG. 7 is a diagram showing an example of a configuration for applying an appropriate load to the light-emitting element when placing the intraoral optical sensor according to an embodiment of the present invention in the oral cavity. FIG. 8 is a diagram showing another example of a configuration for applying an appropriate load to the light-emitting element when placing the intraoral optical sensor according to an embodiment of the present invention in the oral cavity. FIG. 9 is a diagram showing an example of a sealing structure according to an embodiment of the present invention.

[0016]

[0023] (Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 is a diagram showing an example of the functional configuration of an intraoral optical sensor 1 according to this embodiment. The intraoral optical sensor 1 includes a processing unit 10, a sensor unit 11, a power supply unit 12, a wireless communication unit 13, and a storage unit 14.

[0017] The sensor unit 11 includes an optical sensor 110. The optical sensor 110 is fixed to the attachment 5. The attachment 5 is attached to the gums in the oral cavity of a living body. Specific examples of the arrangement of the attachment 5 and the optical sensor 110 will be described later. The optical sensor 110 includes one or more light-emitting elements (for example, one light-emitting element 111) and a light-receiving element 112. Red light and infrared light emitted by the light-emitting element 111 are reflected through the blood. The light-receiving element 112 measures the intensity of this reflected light. The wavelength of the red light is approximately 660 nm. The wavelength of the infrared light is approximately 940 nm.

[0018] The power supply unit 12 supplies power to each of the processing unit 10, the memory unit 14, the sensor unit 11, and the wireless communication unit 13. The power supply unit 12 includes a battery. The battery is, for example, a lithium battery, a silver oxide battery, or a zinc-air battery. It is desirable that the battery have a sufficient battery capacity to allow the intraoral optical sensor 1 to operate in the oral cavity for a long period of time.

[0019] The processing unit 10 performs various processes. For example, the processing unit 10 performs signal processing. The processing unit 10 converts sensing data sent from the sensor unit 11 into digital data and stores it in the storage unit 14. The processing unit 10 also converts the digital data stored in the storage unit 14 into transmittable data. The processing unit 10 interprets commands sent from a network connector (not shown) and controls the operations of the sensor unit 11 and the wireless communication unit 13.

[0020] More specifically, as a signal processing, the processing unit 10 converts the signal measured by the sensor unit 11 into digital data as biometric information. The biometric information may be, for example, one or more of pulse wave, pulse rate, blood oxygen saturation (SpO2), etc. The processing unit 10 transmits the digital data as biometric information obtained by converting the signal to the external reading device 2 via the wireless communication unit 13. The external reading device 2 collects the digital data as biometric information.

[0021] When the processing unit 20 converts the signal measured by the sensor unit 11 into digital data of a pulse wave as biological information, the intraoral optical sensor 1 functions as an intraoral pulse wave measuring device. When the processing unit 20 converts the signal measured by the sensor unit 11 into digital data of SpO2 as biological information, the intraoral optical sensor 1 functions as an intraoral blood oxygen saturation measuring device.

[0022] The processing unit 10 includes, for example, a CPU (Central Processing Unit). The processing unit 10 realizes various processes by the CPU loading a program read from a ROM (Read Only Memory) into a RAM (Random Access Memory) and executing the process in accordance with the program. The ROM and RAM are included in the storage unit 14. The processing unit 10 may include a microcomputer and an AD converter instead of or in addition to the CPU.

[0023] The storage unit 14 stores various types of information. The storage unit 14 includes a memory configured using a storage device such as a semiconductor storage device.

[0024] The wireless communication unit 13 transmits and receives various information via wireless communication. The wireless communication unit 13 transmits digital data obtained by converting sensing data measured by the sensor unit 11 inside the oral cavity by the processing unit 10 to the external reader 2 outside the oral cavity. The wireless communication unit 13 also receives commands transmitted from a network connector (not shown). The wireless communication unit 13 includes a communication interface (I / F) for wireless communication. For example, BLE (Bluetooth (registered trademark) Low Energy) or the like is preferably used for the wireless communication. Note that the wireless communication may be other than BLE.

[0025] The battery included in the power supply unit 12, the optical sensor 110 included in the sensor unit 11, the CPU included in the processing unit 10, the communication I / F included in the wireless communication unit 13, and the memory included in the storage unit 14 are mounted on a substrate 4 (not shown in FIG. 1 ). The substrate 4 is, for example, a thin circuit board or a flexible substrate. In the intraoral optical sensor 1, the battery, the optical sensor 110, the CPU, the memory, and the communication I / F are mounted on the substrate 4. Here, as an example, the communication I / F, the CPU, and the memory are provided on the substrate 4 as a single chip.

[0026] The external reader 2 performs various processes on the digital data serving as biometric information obtained by the intraoral optical sensor 1. The external reader 2 includes a processing unit 20 and a wireless communication unit 21. The processing unit 20 performs various processes on the digital data received by the wireless communication unit 21. The processing unit 20 includes, for example, a CPU. The wireless communication unit 21 receives the digital data from the intraoral optical sensor 1 via wireless communication.

[0027] Here, the measurement and conversion by the optical sensor 110 will be explained. The hemoglobin in the blood has different absorbances for red light and infrared light depending on whether it is bound to oxygen or not. Specifically, deoxygenated hemoglobin (RHb) absorbs red light well, and oxygenated hemoglobin (OHb) absorbs infrared light well. Therefore, by measuring the reflected light intensity of each of the red light and infrared light, the concentration of hemoglobin bound to oxygen in the blood can be estimated.

[0028] In order to distinguish reflected light that has passed through arterial blood from reflected light that has passed through venous blood, soft tissue, etc., the ability to separate a component that is superimposed with pulsation (AC component) and a component that is not due to arterial blood (DC component) is generally utilized. The AC component is necessary for calculating the pulse wave and SpO2. On the other hand, the DC component does not contribute to the pulse wave or SpO2. Therefore, a perfusion index (PI (Perfusion Index) value) is often used as an index indicating how large the AC component is relative to the DC component. The PI value is a value expressed as a percentage of the AC component relative to the DC component. Generally, a PI value of 1.0% or greater is considered desirable to ensure accurate SpO2.

[0029] When placing the optical sensor 110 in the oral cavity, there are certain areas where stable measurements can be made due to the distribution of blood vessels and capillaries in the oral cavity. Stable measurements mean that the PI value is high and SpO2 can be measured accurately. Figure 2 shows an example of the maxillary gum area. Of the maxillary gum areas, Figure 2 shows the maxillary no. 1 palatal gum 31, maxillary no. 2 palatal gum 32, maxillary no. 3 palatal gum 33, maxillary no. 5 palatal gum 35, maxillary no. 6 palatal gum 36, and maxillary no. 7 palatal gum 37.

[0030] Figure 3 shows the results of measuring the PI values ​​at each site on the maxilla. The measured PI values ​​of maxillary no. 1 palatal gingiva 31, maxillary no. 2 palatal gingiva 32, maxillary no. 3 palatal gingiva 33, maxillary no. 5 palatal gingiva 35, maxillary no. 6 palatal gingiva 36, ​​and maxillary no. 7 palatal gingiva 37 were 0.72%, 0.68%, 1.92%, 0.18%, 0.17%, and 0.30%, respectively.

[0031] To ensure accurate SpO2 measurement, it is preferable that the PI value be 1% or greater, with a threshold of 1%. According to actual measurements, the site where the PI value was 1% or greater was the maxillary no. 3 palatal gingiva. Furthermore, sites where the PI value was less than 1% but where measurement was still possible were considered to be areas where the PI value was 0.5% or greater. Sites where the PI value was 0.5% or greater were the maxillary no. 1 palatal gingiva and the maxillary no. 2 palatal gingiva. The maxillary no. 1 palatal gingiva and the maxillary no. 2 palatal gingiva are the sites most suitable for accurate SpO2 measurement, second only to the maxillary no. 3 palatal gingiva.

[0032] Areas where the PI value is 0.5% or higher are areas where SpO2 can be stably measured. Areas where the PI value is 0.5% or higher are the maxillary #1 palatal gingiva, maxillary #2 palatal gingiva, and maxillary #3 palatal gingiva. Therefore, it is preferable that the light-emitting element 111 included in the optical sensor 110 be installed in either the maxillary #1 palatal gingiva, maxillary #2 palatal gingiva, or maxillary #3 palatal gingiva. This configuration allows for stable measurement of SpO2 as a capillary response in either the maxillary #1 palatal gingiva, maxillary #2 palatal gingiva, or maxillary #3 palatal gingiva.

[0033] Furthermore, a region where the PI value is 1% or greater is a region where SpO2 can be measured with particular stability. The region where the PI value is 1% or greater is the palatal gingiva of the maxillary no. 3. Therefore, it is preferable that the light-emitting element 111 provided in the optical sensor 110 be installed on the palatal gingiva of the maxillary no. 3. This configuration allows for particularly stable measurement of SpO2 as a response to capillaries in the palatal gingiva of the maxillary no. 3.

[0034] Note that one optical sensor 110 may include multiple light-emitting elements 111. Furthermore, multiple optical sensors 110 may be installed in the oral cavity. In either the case where one optical sensor 110 includes multiple light-emitting elements 111 or where multiple optical sensors are installed in the oral cavity, it is preferable that the light-emitting elements 111 included in the optical sensor are installed on one or more of the maxillary no. 1 palatal gingiva, maxillary no. 2 palatal gingiva, and maxillary no. 3 palatal gingiva.

[0035] The light-emitting element 111 may also be placed on a portion of the maxillary gingiva other than the maxillary no. 1 palatal gingiva, maxillary no. 2 palatal gingiva, and maxillary no. 3 palatal gingiva. Therefore, the light-emitting element 111 is placed on the maxillary gingiva. By placing the light-emitting element 111 on the maxillary gingiva, the measurement results are less susceptible to the influence of the tongue and there is less of a vomiting reaction. Furthermore, since the maxillary gingiva is connected to central arteries such as the brain by a short distance, placing the light-emitting element 111 on the maxillary gingiva allows changes in central blood oxygen saturation to be measured. The light-emitting element 111 may also be placed on oral tissue other than the maxillary gingiva.

[0036] Furthermore, the measurement accuracy of the optical sensor 110 is also significantly affected by the state of intimate contact (contact) of the light-emitting element 111 with the intraoral surface. Fig. 4 shows an example of a graph showing the change in the relative PI value with respect to the change in the load applied to the light-emitting element 111. The change in load was measured by changing the load when pressing the optical sensor 110 against the intraoral surface on the palatal gingiva of the maxillary no. 3. The relative PI value is a value expressed as a percentage, where the maximum PI value on the palatal gingiva of the maxillary no. 3 is used as a reference value.

[0037] According to the graph shown in Figure 4, the relative PI value is high in the range of 0.3N to 0.8N. In particular, the relative PI value is almost at its maximum in the range of 0.4N to 0.6N. Outside the range of 0.3N to 0.8N, the relative PI value is small compared to the range in question.

[0038] If the load is too small, the contact state will be poor, such as floating. On the other hand, if the load is too large, blood will congeste, blood flow will be poor, and the detection sensitivity of the pulse wave or SpO2 will deteriorate. Therefore, the light-emitting element 111 is arranged so as to be in close contact with the surface of the oral cavity while a load of 0.3 N or more and 0.8 N or less is applied to the light-emitting element 111. More preferably, the light-emitting element 111 is arranged so as to be in close contact with the surface of the oral cavity while a load of 0.4 N or more and 0.6 N or less is applied to the light-emitting element 111.

[0039] The light emitting element 111 is arranged so as to be in close contact with the intraoral surface while applying a load of 0.3 N or more and 0.8 N or less to the light emitting element 111, so that an appropriate load can be applied to the light emitting element 111 that is in close contact with the intraoral surface. This allows the light emitting element 111 to maintain good contact with the intraoral surface and measure a pulse wave or SpO2 that is close to its original state without interfering with blood flow. The pulse wave or SpO2 in its original state is the pulse wave or SpO2 when the intraoral optical sensor 1 is not installed.

[0040] The light emitting element 111 may be arranged so as to be in close contact with the surface of the oral cavity with a load of less than 0.3 N or more than 0.8 N being applied to the light emitting element 111. However, in order to maintain good contact and measure the actual pulse wave or SpO2, it is preferable that the optical element is arranged so as to be in close contact with the surface of the oral cavity with a load of 0.3 N or more and 0.8 N or less being applied to the light emitting element 111.

[0041] The configuration for applying an appropriate load is, as will be described later, a configuration in which the load can be adjusted using a mechanism such as a screw. Alternatively, the load may be controlled by making the optical sensor 110 protrude from the mouthpiece material. To reduce the size of the intraoral optical sensor 1, the latter configuration in which the optical sensor 110 protrudes from the mouthpiece material is preferred.

[0042] Next, the configuration of the attachment 5 will be described with reference to Figures 5 and 6. Figure 5 is a diagram showing an example of the appearance of the intraoral optical sensor 1 when the substrate 4 according to this embodiment is attached to the attachment 5. In the example shown in Figure 5, the attachment 5 is a mouthpiece. The attachment 5 is molded from a resin material that is used as a mouthpiece material, such as polyethylene terephthalate (PET).

[0043] The substrate 4 is housed in a recess (also referred to as a depression) provided in the fixture 5. By housing the substrate 4 in the recess, the optical sensor 110 is fixed to the fixture 5. As shown in Fig. 6 , the optical sensor 110 is fixed so that the light-emitting element 111 is in close contact with the surface of the maxillary gingiva 3.

[0044] In the optical sensor 110, the light emitting element 111 is disposed so that the light emitted from the light emitting element 111 is irradiated onto the gums. In addition, in the optical sensor 110, the light emitting element 111 is disposed so as to be in close contact with the surface of the maxillary gums 3, and the pulse wave or blood oxygen saturation is measured.

[0045] The light-receiving element 112 receives light reflected from the surface of the maxillary gum 3 when light emitted by the light-emitting element 111 is reflected. In other words, the optical sensor 110 is a reflective optical sensor. By using a reflective structure for the optical sensor 110, the light-emitting element 111 and the light-receiving element 112 can be arranged together at a predetermined location in the oral cavity. This allows the intraoral optical sensor 1 to be miniaturized.

[0046] When a transmission-type structure is used for the optical sensor 110, a substrate on which the light-receiving element 112 is mounted is required in addition to the substrate on which the light-emitting element 111 is mounted across the gums. Therefore, the intraoral optical sensor 1 becomes larger than when a reflection-type structure is used for the optical sensor 110. Note that a transmission-type structure may also be used for the optical sensor 110.

[0047] The attachment device 5 may be an intraoral device other than a mouthpiece, such as an orthodontic device (functional device for orthodontic treatment), a denture, an implant, an aligner, or a splint. Therefore, the attachment device 5 is an intraoral device. By using the attachment device 5 as an intraoral device, the intraoral optical sensor 1 can be simultaneously and reliably installed at a predetermined position in the oral cavity through the simple task of attaching the intraoral device to the oral cavity. The attachment device 5 may be something other than an intraoral device as long as it can be attached to the gums in the oral cavity.

[0048] As described above, there is an appropriate range of load when placing the intraoral optical sensor 1 in the oral cavity. A configuration for applying an appropriate load will be described with reference to FIGS. 7 and 8 . FIG. 7 is a diagram showing an example of a configuration for applying an appropriate load to the light-emitting element 111 when placing the intraoral optical sensor 1 in the oral cavity. FIG. 7 shows an intraoral optical sensor 1a as an example of the intraoral optical sensor 1. The intraoral optical sensor 1a includes a substrate 4, an optical sensor 110, a mounting fixture 5a, and a screw 6a.

[0049] The attachment 5a is, for example, a mouthpiece. The substrate 4 and the optical sensor 110 are housed in a recess provided in the attachment 5a. The optical sensor 110 is provided on the substrate 4. The optical sensor 110 is in close contact with the surface of the oral tissue 8 on the side opposite to the substrate 4.

[0050] The fixture 5a has a threaded hole formed on the surface of the fixture 5a opposite to the oral tissue 8. When the screw 6a is fitted into the hole, the tip of the screw 6a comes into contact with the surface of the substrate 4 opposite to the surface on which the optical sensor 110 is provided. By adjusting the height of the part of the screw 6a that protrudes from the surface of the fixture 5a, the screw 6a presses the optical sensor 110 against the oral tissue 8 via the substrate 4. Furthermore, by adjusting the height, the load applied to the optical sensor 110 that is in close contact with the surface of the oral tissue 8 can be adjusted.

[0051] The load applied to the optical sensor 110 may be adjusted appropriately depending on the subject who is the subject of measurement by the intraoral optical sensor 1. Adjusting the load appropriately depending on the subject means adjusting the load depending on, for example, the shape and hardness of the surface of the oral tissue of the subject.

[0052] Fig. 8 is a diagram showing another example of a configuration for applying an appropriate load to the light-emitting element 111 when placing the intraoral optical sensor 1 in the oral cavity. Fig. 8 shows an intraoral optical sensor 1b as an example of the intraoral optical sensor 1. The intraoral optical sensor 1b includes a substrate 4, an optical sensor 110, and an attachment 5b.

[0053] The attachment 5b is, for example, a mouthpiece. A recess is formed in the attachment 5b to accommodate the optical sensor 110 and the substrate 4. The optical sensor 110 is in close contact with the surface of the oral tissue 8 on the side opposite the substrate 4. The side of the substrate 4 opposite the side on which the optical sensor 110 is provided is in contact with a portion of the surface forming the recess of the attachment 5b.

[0054] Here, the material of the attachment 5b is resin. Therefore, the attachment 5b has elasticity. The attachment 5b presses the optical sensor 110 against the oral tissue 8 via the substrate 4 by its elastic force. The load applied to the optical sensor 110, which is in close contact with the surface of the oral tissue 8, is adjusted by the depth of the recess or the protrusion amount of the optical sensor 110. The protrusion amount of the optical sensor 110 is the height of the optical sensor 110 from the surface of the substrate 4 when the optical sensor 110 is placed on the surface of the substrate 4. The greater the protrusion amount of the optical sensor 110, the greater the pressure with which the optical sensor 110 is pressed against the oral tissue 8.

[0055] Intraoral optical sensor 1b does not require components such as screws to press optical sensor 110. Therefore, intraoral optical sensor 1b has a simpler configuration and can be made smaller than intraoral optical sensor 1a ( FIG. 7 ).

[0056] In addition, in either the configuration of the intraoral optical sensor 1a (Figure 7) or the intraoral optical sensor 1b (Figure 8), the optical sensor 110 protrudes toward the oral tissue 8 beyond the surface where the attachment 5 (attachment 5a or attachment 5b) contacts the oral tissue 8.

[0057] When installing the substrate 4 and the optical sensor 110 in the oral cavity, waterproofing is important for safety and stable measurement performance of the intraoral optical sensor 1. A sealing structure for waterproofing will now be described. Figure 9 is a diagram showing an example of a sealing structure according to this embodiment.

[0058] As described above, the optical sensor 110 includes the light-emitting element 111 and the light-receiving element 112. The light-emitting element 111 and the light-receiving element 112 are provided on the substrate 4. A light-shielding plate 113 is provided on the substrate 4 between the light-emitting element 111 and the light-receiving element 112. The light-shielding plate 113 prevents light emitted from the light-emitting element 111 from directly reaching the light-receiving element 112. The light emitted from the light-emitting element 111 is received by the light-receiving element 112. The light-receiving element 112 measures the intensity of the received light. The processing unit 10 (not shown in FIG. 9 ) converts the light intensity as sensing data into digital data. As described above, the digital data indicates biological information such as a pulse wave or SpO2.

[0059] When placing these elements in the oral cavity, providing a waterproof sealing structure is important for safety and stable measurement performance of the device. To achieve this, the structure including the light-emitting element 111 and the light-receiving element 112 is first sealed with a first resin 6. The first resin 6 is, for example, an epoxy resin or an acrylic resin. The material of the first resin 6 is preferably a material that ensures electrical insulation and is transparent to the wavelength of light emitted by the light-emitting element 111.

[0060] Furthermore, in order to obtain biocompatibility, it is preferable to further seal with a second resin 7. The second resin 7 is a transparent resin. The second resin 7 is a biocompatible material such as parylene. The second resin 7 is the mounting fixture 5 itself.

[0061] Therefore, the light-emitting element 111 and the light-receiving element 112 are sealed with a transparent resin consisting of two or more layers. The transparent resin consisting of two or more layers is a first resin 6 and a second resin 7. The light-emitting element 111 is in close contact with the surface of the oral tissue 8 via the resins (first resin 6 and second resin 7). Of the two or more resin layers, the layer (second resin 7) that comes into contact with the surface of the oral tissue 8 is, for example, parylene.

[0062] The above-described sealing structure allows the intraoral optical sensor 1 to be safely installed in the oral cavity while ensuring waterproofing, and also ensures electrical insulation and structural stability.

[0063] As described above, the intraoral optical sensor 1 according to the present embodiment includes the attachment 5 and the optical sensor 110. The attachment 5 is attached to the gums in the oral cavity. The optical sensor 110 is fixed to the attachment 5. The optical sensor 110 includes one or more light-emitting elements (one light-emitting element 111 in the present embodiment) and a light-receiving element 112. The optical sensor 110 measures a pulse wave or blood oxygen saturation (SpO2) by arranging the one or more light-emitting elements (one light-emitting element 111 in the present embodiment) so that light emitted from the one or more light-emitting elements (one light-emitting element 111 in the present embodiment) is irradiated onto the gums (one of the maxillary no. 1 palatal gingiva, the maxillary no. 2 palatal gingiva, or the maxillary no. 3 palatal gingiva in the present embodiment) and by arranging the one or more light-emitting elements (one light-emitting element 111 in the present embodiment) in close contact with the surface of the oral tissue.

[0064] With this configuration, the intraoral optical sensor 1 of this embodiment can irradiate the gums with light emitted by the light-emitting element arranged in close contact with the surface of the oral tissue, thereby enabling stable measurement of pulse waves or blood oxygen saturation.

[0065] The intraoral optical sensor 1 can measure pulse waves or SpO2 when placed on the gums in the oral cavity and stably fixed in the oral cavity using the attachment 5. Measuring pulse waves or SpO2 in the oral cavity has the following effects.

[0066] One of the advantages of measuring pulse waves or SpO2 in the oral cavity is that it can be measured in the oral cavity even in patients with peripheral circulatory disorders. One of the advantages of measuring pulse waves or SpO2 in the oral cavity is that it is highly likely that measurements can be made even in patients with injured fingers or ears, because the oral cavity is less likely to be burned.

[0067] One advantage of measuring pulse waves or SpO2 intraorally is that it can be used during sleep or exercise because it places minimal physical constraints on the body. Conventional extraoral measurement techniques include a sensor that is fixed to the forehead with tape, but it is difficult to stably fix the sensor and therefore difficult to achieve stable measurements.

[0068] One of the benefits of measuring pulse waves or SpO2 intraoral is that it can add sensing functionality to intraoral devices (such as orthodontic appliances (functional appliances for orthodontic treatment), dentures, implants, mouthpieces, aligners, or splints) that are used daily by people of all ages, from children to the elderly. This allows more accurate biometric information to be obtained from people of all ages, increasing the possibility of intervention before symptoms worsen. Therefore, the intraoral optical sensor 1 can be ideally used for daily individual health management or in home medical care.

[0069] One advantage of measuring pulse waves or SpO2 in the oral cavity is that the surface skin is thin inside the oral cavity, so the influence of light reflection by the surface skin is small. Another advantage of measuring pulse waves or SpO2 in the oral cavity is that the influence of external light can be blocked because it is inside the oral cavity. This allows for stable measurements. Another advantage of measuring pulse waves or SpO2 in the oral cavity is that the influence of skin color (race) on the measurement results is small.

[0070] One advantage of measuring pulse waves or SpO2 in the mouth is that a decrease in SpO2 can be detected more sensitively in the mouth than with a finger. For example, it has been confirmed that the lowest SpO2 value when holding one's breath is significantly lower in the mouth than with a finger. Therefore, even if a physical abnormality occurs and SpO2 decreases, the physical abnormality can be discovered earlier.

[0071] One embodiment of the present invention has been described in detail above with reference to the drawings, but the specific configuration is not limited to that described above, and various design changes and the like are possible within the scope that does not deviate from the gist of the present invention.

[0072] 1, 1a, 1b... intraoral optical sensor, 5... attachment, 110... optical sensor, 111... light-emitting element, 112... light-receiving element

Claims

1. An intraoral optical sensor comprising: an attachment to be attached to the gums inside the oral cavity; and an optical sensor fixed to the attachment, wherein the optical sensor comprises one or more light-emitting elements and a light-receiving element, and the light-emitting element is positioned so that light emitted from the light-emitting element is irradiated onto the gums and the light-emitting element is positioned so that it is in close contact with the surface of tissue in the oral cavity, thereby measuring pulse waves or blood oxygen saturation.

2. The intraoral optical sensor according to claim 1, wherein the light receiving element receives reflected light resulting from light emitted by the light emitting element being reflected by tissue in the oral cavity.

3. The intraoral optical sensor according to claim 2, wherein the light-emitting element is placed on the gums of the upper jaw.

4. The intraoral optical sensor according to claim 3, wherein the light-emitting element is installed on either the maxillary no. 1 palatal gingiva, the maxillary no. 2 palatal gingiva, or the maxillary no. 3 palatal gingiva.

5. The intraoral optical sensor according to claim 4, wherein the light-emitting element is placed on the palatal gingiva of the maxillary third tooth.

6. The intraoral optical sensor according to claim 2, wherein the light-emitting element is arranged so as to be in close contact with the intraoral surface under a load of 0.3 N or more and 0.8 N or less.

7. The intraoral optical sensor as described in claim 1, wherein the light-emitting element and the light-receiving element are sealed with a transparent resin consisting of two or more layers, the light-emitting element is in close contact with the intraoral surface via the resin, and the layer of the two or more layers of the resin that comes into contact with the intraoral surface is parylene.

8. The intraoral optical sensor according to claim 1, wherein the attachment is an intraoral device.

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