Pressure sensor sheet for oral cavity

Abstract

To provide a pressure sensor sheet for an oral cavity that has a simple structure, can be easily manufactured, can accurately measure an occlusal force of a pair of upper and lower teeth, and has a new structure.SOLUTION: A pressure sensor sheet 10 for an oral cavity comprises a measuring portion 12 on a tip side to be inserted into an oral cavity. The measuring portion 12 has a detecting region 56 (62) on which an occlusal force caused by occlusion of one or two pairs of upper and lower teeth is exerted. A plurality of pressure sensitive elements 54 (60) for detecting a pressure are arranged in a sheet surface direction on a pressure sensitive part 58 (64) for a pair of teeth for detecting an occlusal force caused by a pair of upper and lower teeth in the detecting region 56 (62).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an oral cavity pressure sensor sheet used to measure the bite force of a subject. [Background technology]

[0002] For example, it may be necessary to grasp the magnitude of occlusal force during dental checkups, treatment, etc. Conventionally, occlusal force has been estimated by, for example, biting a carbon sheet and checking the carbon attached to the teeth, but there have been problems such as it being difficult to grasp the magnitude of occlusal force accurately and the subject feeling uneasy about biting down hard on a thin carbon sheet.

[0003] Therefore, for example, Japanese Patent Laid-Open Publication No. 2023-128974 (Patent Document 1) proposes an oral pressure measuring device for more accurately measuring occlusal force. The oral pressure measuring device of Patent Document 1 has a sensor unit equipped with a first pressure sensor and a second pressure sensor capable of measuring pressure, and when the subject applies occlusal force to the first pressure sensor or the second pressure sensor, the occlusal force can be measured based on the detected pressure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-128974 Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, the first pressure sensor and the second pressure sensor are capable of measuring pressure independently of each other, and one pressure sensor can measure the occlusal force of a part of the dentition, such as the molars and front teeth. In Patent Document 1, in order to prevent force transmission between the first pressure sensor and the second pressure sensor, a first flat plate covering the surface (main surface) of the first pressure sensor and a second flat plate covering the surface of the second pressure sensor are arranged apart from each other.

[0006] However, for example, when trying to measure the occlusal force of a pair of upper and lower teeth using a single sensor element (pressure sensor), detection errors due to the unevenness of the occlusal surfaces of the teeth can become a problem. That is, when occlusal force is applied, the flat plate covering the surface of the pressure sensor can be deformed by being pressed against the unevenness of the teeth, and part of the deformed flat plate can be held in a state pressed against the pressure sensor, which can affect the detected value of occlusal force, or the action of the occlusal force on the pressure sensor can be hindered by the deformed flat plate.

[0007] The problem to be solved by the present invention is to provide an oral cavity pressure sensor sheet with a novel structure that can more accurately measure the occlusal force of a pair of upper and lower teeth. [Means for solving the problem]

[0008] The following describes preferred embodiments for understanding the present invention, but the embodiments described below are merely examples and may be appropriately combined with one another. Multiple components described in each embodiment may be recognized and employed independently to the greatest extent possible, and may also be appropriately combined with any of the components described in other embodiments. Accordingly, the present invention is not limited to the embodiments described below, and various other embodiments may be realized.

[0009] The first aspect is an oral pressure sensor sheet having a measuring portion at the tip side that is inserted into the oral cavity, the measuring portion having a detection area where the occlusal force caused by the bite of one or two pairs of upper and lower teeth is exerted, and the pair of teeth pressure sensing portion that detects the occlusal force caused by the pair of upper and lower teeth in the detection area has multiple pressure sensing elements that detect pressure arranged in the direction of the sheet surface.

[0010] If an attempt is made to detect the occlusal force of a pair of upper and lower teeth using a single pressure-sensitive element, the unevenness of the occlusal surface may cause the pressure-sensitive element to tilt or deform into a stepped shape, which could reduce the accuracy of occlusal force detection. Therefore, in the oral cavity pressure sensor sheet according to this embodiment, the occlusal force of a pair of upper and lower teeth is detected using a pressure-sensitive unit for a pair of teeth that includes multiple pressure-sensitive elements. This reduces the adverse effect on detection accuracy caused by the unevenness of the occlusal surface of the pair of upper and lower teeth, allowing for more accurate measurement of the magnitude of occlusal force.

[0011] In a second aspect, in the oral cavity pressure sensor sheet described in the first aspect, the pressure-sensitive element has an electrode that is not fixedly attached to and superimposed on the compressible and deformable intermediate layer.

[0012] In the oral pressure sensor sheet constructed according to this embodiment, since the intermediate layer is not fixed to the electrode, even if the electrode is deformed by the occlusal force acting on the pressure-sensitive element, the thickness dimension of the intermediate layer can be prevented from changing in accordance with the deformation of the electrode. Therefore, by preventing the intermediate layer from being constrained by the electrode and causing errors in the detection results, the accuracy of measuring occlusal force can be improved.

[0013] In a third aspect, in the oral pressure sensor sheet described in the first or second aspect, the pressure-sensitive element has a structure in which flexible electrodes are arranged on both sides of a compressible and deformable intermediate layer.

[0014] According to the oral pressure sensor sheet constructed in accordance with this embodiment, the pressure-sensitive element that applies the bite force has a flexible structure in which a compressible and deformable intermediate layer and flexible electrodes are arranged, so that the person being measured is less likely to feel uneasy when biting down hard on the pressure-sensitive element, and is less likely to experience pain or discomfort, compared to biting down on a hard pressure-sensitive element.

[0015] Furthermore, flexible pressure-sensitive elements have excellent conformability to the unevenness of the occlusal surfaces of a pair of upper and lower teeth, and thus the decrease in detection accuracy due to the unevenness of the occlusal surfaces is suppressed. In particular, for example, when an electrode is arranged across multiple pressure-sensitive elements, if the electrode is flexible, the transmission of force between the multiple pressure-sensitive elements due to the deformation rigidity of the electrode is suppressed, and therefore the conformability to the unevenness of the occlusal surfaces of the teeth in the pressure-sensitive unit for a pair of teeth including the multiple pressure-sensitive elements is improved, and the accuracy of occlusal force detection can be further improved.

[0016] A fourth aspect is an oral pressure sensor sheet described in the second or third aspect, in which a reinforcing material layer having greater deformation rigidity than the intermediate layer is superimposed on each of the plurality of pressure-sensitive elements on the outside of the electrodes arranged on both sides of the intermediate layer, and is provided across each of the plurality of pressure-sensitive elements.

[0017] When the occlusal force of a pair of upper and lower teeth is applied to multiple electrodes, there is a risk of excessive unbalanced load depending on the bite style. With flexible electrodes, excessive force acting only on specific electrodes can damage the electrodes or crush specific electrode areas, resulting in measurement errors. Therefore, in the oral pressure sensor sheet constructed according to this embodiment, multiple electrodes are arranged in the detection area of ​​the occlusal force of the teeth, ensuring the flexibility of each electrode, while the occlusal force acting on these multiple electrodes is distributed and applied by a common reinforcing material layer. This effectively prevents damage to the electrodes due to unbalanced loads, etc., and enables more reliable measurement of occlusal force.

[0018] A fifth aspect is an oral pressure sensor sheet according to the fourth aspect, wherein the pressure-sensing unit for a pair of teeth has a compressible buffer body superimposed on each outermost side of the reinforcing material layer arranged on both sides of the intermediate layer, the buffer body being large enough to completely cover the reinforcing material layer, and the thickness of the reinforcing material layer is larger than the thickness of the intermediate layer and smaller than the thickness of the buffer body.

[0019] In the oral pressure sensor sheet constructed according to this embodiment, first, by ensuring a sufficient thickness of the buffer, the effect of improving the bite comfort when a occlusal force is applied to the reinforcement layer, which is harder than the buffer. Furthermore, if the reinforcement layer is significantly deformed by the occlusal force, there is a risk of damage to the electrodes and dielectric layer, which are generally more susceptible to deformation than the reinforcement layer. However, by making the reinforcement layer thicker than the dielectric layer, the occlusal force dispersion effect of the reinforcement layer is more effectively exerted, preventing damage to the electrodes and dielectric layer. Furthermore, by making the reinforcement layer thicker than the dielectric layer and increasing its deformation rigidity, it is possible to suppress shear deformation and efficiently generate compressive deformation when the occlusal force is applied to the dielectric layer through the reinforcement layer, leading to improved measurement accuracy.

[0020] The sixth aspect is an oral pressure sensor sheet according to the fifth aspect, wherein the electrodes are fixedly held by base sheets arranged on both sides of the intermediate layer, and the thickness dimension of the reinforcing material layer is greater than the thickness dimension of the base sheets.

[0021] In an oral pressure sensor sheet constructed in accordance with this embodiment, the thickness of the base sheet can be reduced to improve measurement sensitivity, while the reinforcing layer can effectively prevent damage to the base sheet.

[0022] In a seventh aspect, in the oral pressure sensor sheet described in the second or third aspect, each of the multiple pressure-sensitive elements is provided with a reinforcing material layer having a deformation rigidity greater than that of the intermediate layer.

[0023] In the oral pressure sensor sheet constructed according to this embodiment, the bite force is distributed over a wide area of ​​the intermediate layer of each pressure-sensitive element via the reinforcing material layer, which makes it difficult for the intermediate layer of each pressure-sensitive element to undergo local deformation so large that accurate detection is impossible, thereby improving the detection accuracy of each pressure-sensitive element.

[0024] Furthermore, since a separate reinforcing material layer is provided for each pressure-sensitive element, the reinforcing material layer prevents the bite force from being applied across multiple pressure-sensitive elements, ensuring the independence of the bite force detection results of each pressure-sensitive element. Therefore, the unevenness of the bite surfaces of a pair of upper and lower teeth is less likely to affect the bite force detection accuracy, making it possible to detect bite force with higher accuracy.

[0025] It should be noted that the fifth and sixth aspects can both be employed in combination with this aspect (seventh aspect), thereby making it possible to enjoy the effects as described above.

[0026] The eighth aspect is an oral pressure sensor sheet described in any one of the first to seventh aspects, in which a connection support portion having a plurality of electrical contacts for external connection is provided on the base end side, the connection support portion and the measurement portion are connected by an intermediate portion, and base sheets on both the front and back sides are provided in a state that extends over the area from the measurement portion through the intermediate portion to the connection support portion, and in the intermediate portion that is positioned both inside and outside the oral cavity when the measurement portion is inserted into the oral cavity, the base sheets on both the front and back sides are fixed with a reinforcing sheet in between.

[0027] With an oral pressure sensor sheet constructed according to this aspect, for example, when the measurement portion is inserted into the oral cavity of a subject to measure occlusal force, it is possible to use the middle portion to push apart the corners of the subject's mouth. In particular, in this aspect, the middle portion is constructed such that a reinforcing sheet is sandwiched and fixed between the base sheets on both the front and back sides, and the deformation rigidity of the middle portion is set to be sufficiently large, so that deformation or damage to the middle portion can be avoided even if the corners of the mouth are pushed apart with the middle portion.

[0028] A ninth aspect is an oral pressure sensor sheet described in any one of the first to eighth aspects, wherein the measurement portion has a tapered shape with a smaller left-right width dimension at the tip side than at the base end side, and the measurement portion has the detection area for back teeth with a smaller left-right width dimension positioned more toward the tip side than the detection area for front teeth with a larger left-right width dimension.

[0029] The oral cavity pressure sensor sheet constructed according to this embodiment can measure the bite force of both molars and front teeth using a single oral cavity pressure sensor sheet. Furthermore, since the detection area for molars, which measures the bite force of a pair of upper and lower teeth, has a small lateral width, while the detection area for front teeth, which measures the bite force of two pairs of upper and lower teeth, has a large lateral width, the detection areas can be arranged more space-efficiently by locating the detection area for molars more distally than the detection area for front teeth in the tapered measurement section. Furthermore, when measuring the bite force of molars, the detection area needs to be inserted further back into the oral cavity than when measuring the bite force of front teeth. However, by locating the detection area for molars more distally than the detection area for front teeth in the measurement section, it becomes easier to insert the detection area for molars further back into the oral cavity. In particular, the tapered shape of the measurement section makes it easier to insert the measurement section into the oral cavity. [Effects of the Invention]

[0030] According to the present invention, the bite force of a pair of upper and lower teeth can be measured more accurately using an oral cavity pressure sensor sheet. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 1 is a plan view showing an oral cavity pressure sensor sheet according to a first embodiment of the present invention; [Figure 2] 2 is a partial cross-sectional view of the oral cavity pressure sensor sheet shown in FIG. 1, corresponding to the cross section II-II of FIG. 1; [Figure 3] A plan view of the dielectric layer that constitutes the oral pressure sensor sheet shown in Figure 1. [Figure 4]FIG. 2 is a plan view of a first electrode layer constituting the oral cavity pressure sensor sheet shown in FIG. 1. [Figure 5] FIG. 2 is a plan view of a second electrode layer constituting the oral cavity pressure sensor sheet shown in FIG. [Figure 6] A plan view of the guard layer that constitutes the oral pressure sensor sheet shown in Figure 1. [Figure 7] FIG. 3 is a cross-sectional view corresponding to FIG. 2, showing an oral cavity pressure sensor sheet according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0033] 1 and 2 show an oral pressure sensor sheet 10 according to a first embodiment of the present invention. The oral pressure sensor sheet 10 detects the occlusal force generated by the occlusion of one or two pairs of upper and lower teeth and is a thin, flexible sheet. In the following description, the vertical direction generally refers to the vertical direction in FIG. 2, which is the thickness direction in which the occlusal force acts; the front-rear direction generally refers to the vertical direction in FIG. 1, which is the length direction; and the left-right direction generally refers to the left-right direction in FIG. 1, which is the width direction. In this embodiment, the sheet surface direction generally refers to the direction perpendicular to the vertical direction, which is the thickness direction of the sheet. In FIG. 1, a second conductive portion 42, which will be described later and which is covered by a dielectric layer 18, is also shown in a see-through state for ease of understanding.

[0034] The oral pressure sensor sheet 10 is elongated in the front-to-rear direction and includes a measuring portion 12 that forms the tip portion inserted into the oral cavity, a connecting support portion 14 that forms the rear end portion, and an intermediate portion 16 that extends in the front-to-rear direction and connects the measuring portion 12 and the connecting support portion 14. The measuring portion 12 is the portion that is inserted into the oral cavity when measuring occlusal force, and has a tapered shape that narrows in the left-to-right direction toward the front side (the tip). The connecting support portion 14 is the portion that is located outside the oral cavity when measuring occlusal force, and is wider in the left-to-right direction than the measuring portion 12 and the intermediate portion 16. The intermediate portion 16 is the portion that is located both inside and outside the oral cavity when measuring occlusal force, and has approximately the same width as the base end of the measuring portion 12, and extends linearly in the front-to-rear direction with an approximately constant width.

[0035] The oral pressure sensor sheet 10 has a laminated structure in which a first electrode layer 20 and a second electrode layer 22 are laminated on both sides of a dielectric layer 18 serving as an intermediate layer. The dielectric layer 18 is a flexible sheet formed from rubber, synthetic resin elastomer, or the like, and is compressively deformable in the thickness direction. The dielectric layer 18 is preferably formed from an electrically insulating material with a high relative dielectric constant. As shown in FIG. 3 , the dielectric layer 18 has a shape and size that constitutes the measurement portion 12 to the intermediate portion 16 of the oral pressure sensor sheet 10. The intermediate portion 16, which is located between the inside and outside of the oral cavity when the measurement portion 12 of the oral pressure sensor sheet 10 is inserted into the oral cavity, has a structure in which first and second electrode layers 20 and 22, described below, serving as base sheets, are bonded to both the front and back sides of the dielectric layer 18 serving as a reinforcing sheet, and the dielectric layer 18 improves deformation rigidity.

[0036] The first electrode layer 20 is in the form of a sheet that is flexibly deformable in the thickness direction, and is superimposed on the upper surface of the dielectric layer 18. The first electrode layer 20 extends over the region of the oral pressure sensor sheet 10, from the measurement portion 12 through the intermediate portion 16 to the connection support portion 14. As shown in Figures 2 and 4, the first electrode layer 20 has a structure in which a conductive first conductive portion 26 is provided on the upper surface of an electrically insulating first substrate portion 24.

[0037] The first substrate portion 24 is made of, for example, a synthetic resin film and has a longitudinal shape extending in the front-to-rear direction. When viewed from the top-to-bottom direction, the front end portion and the front-to-rear middle portion of the first substrate portion 24 have substantially the same shape and size as the measurement portion 12 and the middle portion 16 of the oral pressure sensor sheet 10. When viewed from the top-to-bottom direction, the rear end portion of the first substrate portion 24 has a shape that substantially corresponds to the middle portion of the connection support portion 14 of the oral pressure sensor sheet 10. The first substrate portion 24 preferably has flexibility in the thickness direction that allows it to follow the compressive deformation of the dielectric layer 18. Furthermore, since the first substrate portion 24 is sheet- or plate-shaped, its deformation rigidity is higher in the width direction than in the thickness direction. As shown in FIG. 4 , the first substrate portion 24 has a V-shaped mark 28 that indicates the center position in the left-to-right direction. The length in the anterior-posterior direction of the portion of the first substrate part 24 that constitutes the measurement part 12 is set so as to facilitate insertion into the oral cavity, and is preferably within the range of 10 to 50 mm, more preferably within the range of 20 to 40 mm. Also, the length in the anterior-posterior direction of the portion of the first substrate part 24 that constitutes the intermediate part 16 is preferably within the range of 30 to 100 mm, more preferably within the range of 40 to 70 mm.

[0038] The first conductive portion 26 preferably has flexibility that allows it to follow the deformation of the first substrate portion 24. The first conductive portion 26 can be formed, for example, from a conductive material in which a conductive material is mixed with a binder made of cross-linked rubber and thermoplastic elastomer, or from conductive fibers. The first conductive portion 26 of this embodiment is formed from a conductive material in which a conductive material is mixed with a binder.

[0039] The first conductive section 26 includes three first terminals 30a, 30b, and 30c serving as electrical contacts for external connection and provided at the rear end portion constituting the connection support section 14, first molar electrodes 32a and 32b and a first anterior tooth electrode 34 serving as electrodes provided at the front end portion constituting the measurement section 12, and three first wiring portions 36a, 36b, and 36c connecting the first terminals 30a to 30c with the first molar electrodes 32a, 32b and the first anterior tooth electrode 34. A control device 38 (see FIG. 1) electrically connected to the first terminals 30a to 30c is electrically connected to the first molar electrodes 32a and 32b and the first anterior tooth electrode 34 via the first wiring portions 36a to 36c.

[0040] 4, the first molar electrodes 32 are strip-shaped and extend in the left-right direction, and two of them are arranged side by side at positions close to but separated from each other in the front-rear direction. The first molar electrodes 32a, 32b are provided at the tip portion of the first substrate portion 24.

[0041] The first anterior tooth electrode 34 has a strip shape extending in the left-right direction and has a larger left-right length than the first molar tooth electrodes 32a, 32b. The first anterior tooth electrode 34 is provided further rearward than the first molar tooth electrodes 32a, 32b. The front end portion of the first substrate portion 24, on which the first molar tooth electrodes 32a, 32b and the first anterior tooth electrode 34 are provided, has a tapered shape whose left-right width decreases toward the front, and the first molar tooth electrodes 32a, 32b are provided on the tip side of the first substrate portion 24, where the left-right width is smaller.

[0042] The second electrode layer 22 is in the form of a sheet that is flexibly deformable in the thickness direction, and is superimposed on the upper surface of the dielectric layer 18. The second electrode layer 22 extends over the region of the oral pressure sensor sheet 10, from the measurement portion 12 through the intermediate portion 16 to the connection support portion 14. As shown in Figures 2 and 5, the second electrode layer 22 has a structure in which a conductive second conductive portion 42 is provided on the upper surface of an electrically insulating second substrate portion 40.

[0043] The second substrate portion 40 is made of, for example, a synthetic resin film and has a longitudinal shape extending in the front-to-rear direction. When viewed from the top-to-bottom direction, the front end portion and the front-to-rear middle portion of the second substrate portion 40 have substantially the same shape and size as the measurement portion 12 and the middle portion 16 of the oral pressure sensor sheet 10. When viewed from the top-to-bottom direction, the rear end portion of the second substrate portion 40 has a shape that substantially corresponds to the right end portion of the connection support portion 14 of the oral pressure sensor sheet 10. Therefore, the front end portion and the front-to-rear middle portion of the second substrate portion 40, excluding the rear end portion, have substantially the same shape and size as the first substrate portion 24. It is preferable that the second substrate portion 40 has flexibility that allows it to deform in response to compressive deformation of the dielectric layer 18. Furthermore, since the second substrate portion 40 is sheet- or plate-shaped, its deformation rigidity in the width direction is higher than that in the thickness direction.

[0044] The second conductive portion 42 preferably has flexibility that allows it to follow the deformation of the second substrate portion 40. The second conductive portion 42 can be formed, for example, from a conductive material in which a conductive material is mixed with a binder made of cross-linked rubber and thermoplastic elastomer, or from conductive fibers. The second conductive portion 42 of this embodiment is formed from a conductive material in which a conductive material is mixed with a binder.

[0045] The second conductive portion 42 includes three second terminals 44a, 44b, and 44c serving as electrical contacts for external connection and provided at a rear end portion constituting the connection support portion 14, second molar electrodes 46a and 46b and second anterior teeth electrodes 48a, 48b, and 48c serving as electrodes provided at a front end portion constituting the measurement portion 12, and three second wiring portions 50a, 50b, and 50c connecting the second terminals 44a to 44c with the second molar electrodes 46a and 46b and the second anterior teeth electrodes 48a to 48c. The second wiring portion 50b extends forward over the second anterior teeth electrode 48b and is connected to the second molar teeth electrode 46a, electrically connecting the second terminal 44b with the second molar teeth electrode 46a and the second anterior teeth electrode 48b. The second wiring portion 50c extends forward over the second anterior tooth electrode 48c and is connected to the second molar tooth electrode 46b, electrically connecting the second terminal portion 44c to the second molar tooth electrode 46b and the second anterior tooth electrode 48c. The control device 38 (see FIG. 1), which is electrically connected to the second terminal portions 44a-44c, is electrically connected to the second molar tooth electrodes 46a, 46b and the second anterior tooth electrodes 48a-48c via the second wiring portions 50a-50c. A plurality of positioning holes 51 penetrating the thickness direction are formed in the rear end portions of the first and second substrate portions 24, 40 at positions spaced apart from the first and second terminal portions 30a-30c, 44a-44c. Positioning pins (not shown) provided on the control device 38 are inserted into the positioning holes 51 to position the connection support portion 14 of the oral pressure sensor sheet 10 and the control device 38.

[0046] 5, the second molar electrodes 46 are strip-shaped and extend in the front-rear direction, and two of them are arranged side by side at positions close to but separated from each other in the left-right direction. The second molar electrodes 46a, 46b are provided at the tip portion of the second substrate portion 40.

[0047] The second front tooth electrodes 48 are strip-shaped and extend in the front-rear direction, and three of them are arranged side by side at positions close to but spaced apart from each other in the left-right direction. The left and right ends of the three second front tooth electrodes 48a to 48c are located laterally outward from the left and right ends of the two second molar tooth electrodes 46a, 46b. The second front tooth electrode 48 has a smaller length in the front-rear direction than the second molar tooth electrode 46. The second front tooth electrode 48 is provided further posteriorly than the second molar tooth electrode 46. The front end portion of the second substrate unit 40, on which the second molar tooth electrodes 46a, 46b and the second front tooth electrodes 48a to 48c are provided, has a tapered shape whose left-right width decreases toward the front, and the second molar tooth electrodes 46a, 46b are provided at the tip side of the second substrate unit 40, where the left-right width is smaller.

[0048] The materials forming the first and second substrate portions 24, 40 are not limited, but suitable examples include synthetic resin materials such as polyethylene terephthalate (PET), polypropylene, and polyamide. The binder for the first and second conductive portions 26, 42 can be made of the same synthetic resin material as that for the first and second substrate portions 24, 40. While the first and second substrate portions 24, 40 are preferably made of the same material, they may also be made of different materials. Similarly, the binder materials for the first and second conductive portions 26, 42 may be made of different materials. The materials forming the first substrate portion 24 and the binder materials for the first conductive portion 26 may be the same or different. The materials forming the second substrate portion 40 and the binder materials for the second conductive portion 42 may also be the same or different.

[0049] The conductive material of the first and second conductive parts 26, 42 is not limited, but may be appropriately selected from, for example, metal particles made of silver, gold, copper, nickel, rhodium, palladium, chromium, titanium, platinum, iron, and alloys thereof, metal oxide particles made of zinc oxide, titanium oxide, and the like, metal carbide particles made of titanium carbonate, metal nanowires made of silver, gold, copper, platinum, nickel, and the like, carbon black, carbon nanotubes, graphite, thin-layer graphite, graphene, and other conductive carbon materials.

[0050] As shown in Fig. 2, the first electrode layer 20 and the second electrode layer 22 are bonded to both sides of the dielectric layer 18 with an adhesive 52 and are arranged opposite each other with the dielectric layer 18 sandwiched between them in the vertical direction. The first and second electrode layers 20, 22 are bonded to the dielectric layer 18 with the adhesive 52 at their tip portions that are spaced forward from the first molar electrodes 32a, 32b and the second molar electrodes 46a, 46b, and are also bonded to the dielectric layer 18 with the adhesive 52 at their portions that are spaced rearward from the first anterior electrode 34 and the second anterior electrodes 48a-48c. In Fig. 1, the bonded areas with the adhesive 52 are shown colored gray.

[0051] As a result, the first and second electrode layers 20, 22 and the dielectric layer 18 are overlapped without being bonded to each other in the areas where the first molar electrodes 32a, 32b and the second molar electrodes 46a, 46b and the first anterior electrode 34 and the second anterior electrode 48a-48c are disposed. In particular, on the upper surface side of the dielectric layer 18, the first molar electrodes 32a, 32b and the first anterior electrode 34 are configured such that a gap 53 exists between the first substrate portion 24 supporting them and the dielectric layer 18. Furthermore, the first and second electrode layers 20, 22 and the dielectric layer 18 are bonded to each other in the middle portion 16 with an adhesive 52. By bonding the first and second electrode layers 20, 22 and the dielectric layer 18 to each other in this manner, the deformation rigidity of the middle portion 16 in the width direction and the length direction is increased, and the reinforcing effect of the hardened adhesive 52 also increases the deformation rigidity of the middle portion 16.

[0052] The first molar electrodes 32a, 32b of the first electrode layer 20 and the second molar electrodes 46a, 46b of the second electrode layer 22 are arranged opposite each other in the vertical direction with the dielectric layer 18 sandwiched therebetween. A molar pressure-sensing element 54 is formed in the opposing portion of the first molar electrodes 32a, 32b and the second molar electrodes 46a, 46b, whose capacitance changes in response to a change in the distance between the opposing surfaces of the first molar electrodes 32a, 32b and the second molar electrodes 46a, 46b that accompanies compressive deformation of the dielectric layer 18. In this embodiment, as shown in FIG. 1 , a pair of first molar electrodes 32a, 32b extending in the left-right direction and a pair of second molar electrodes 46a, 46b extending in the front-rear direction are arranged opposite each other, thereby forming four molar pressure-sensing elements 54a, 54b, 54c, and 54d. The four molar pressure-sensing elements 54a-54d are arranged two by two in the front-rear and left-right directions. In the areas where the molar pressure-sensing elements 54a-54d are formed, the first and second electrode layers 20, 22 are not fixed to the dielectric layer 18, and the first molar electrodes 32a, 32b and the second molar electrodes 46a, 46b are overlapped on the dielectric layer 18 without being fixed thereto.

[0053] The molar detection area 56, which serves as a detection area on which the occlusal force caused by the occlusion of a pair of upper and lower molars acts, is constituted by these four molar pressure-sensing elements 54a to 54d. The molar detection area 56, which is constituted by the four molar pressure-sensing elements 54a to 54d, is a substantially square area when viewed from the up-down direction. In this embodiment, since the molar detection area 56 serves as an area on which the occlusal force caused by the occlusion of a pair of upper and lower molars acts, the molar detection area 56 is constituted by a pair of molar pressure-sensing unit 58 as a single pair of teeth pressure-sensing unit. Therefore, the pair of molar pressure-sensing unit 58 is constituted by four molar pressure-sensing elements 54a to 54d, which are arranged two by two on the front, back, left, and right sides.

[0054] The first front tooth electrode 34 of the first electrode layer 20 and the second front tooth electrodes 48a-48c of the second electrode layer 22 are arranged to face each other in the vertical direction with the dielectric layer 18 sandwiched therebetween. A front tooth pressure-sensitive element 60 is formed in the opposing portion of the first front tooth electrode 34 and the second front tooth electrode 48, and its capacitance changes in response to a change in the distance between the opposing surfaces of the first front tooth electrode 34 and the second front tooth electrode 48, which is accompanied by compressive deformation of the dielectric layer 18. In this embodiment, as shown in Fig. 1, one first front tooth electrode 34 extending in the left-right direction and three second front tooth electrodes 48a-48c extending in the front-rear direction are arranged to face each other, thereby forming three front tooth pressure-sensitive elements 60a, 60b, 60c. In the area where the front tooth pressure-sensitive elements 60a to 60c are formed, the first and second electrode layers 20, 22 are not fixed to the dielectric layer 18, and the first front tooth electrode 34 and the second front tooth electrodes 48a to 48c are overlapped on the dielectric layer 18 without being fixed thereto.

[0055] The three front teeth pressure-sensitive elements 60a-60c constitute a front teeth detection region 62, which serves as a detection region for detecting the occlusal force due to the occlusion of the two pairs of upper and lower front teeth. The front teeth detection region 62 includes two pair of front teeth pressure-sensitive units 64, arranged side by side on the left and right, that detect the occlusal force due to the occlusion of the pair of upper and lower front teeth. Specifically, the left front teeth pressure-sensitive element 60a and the central front teeth pressure-sensitive element 60b constitute one pair of front teeth pressure-sensitive unit 64a that detects the occlusal force of the left pair of upper and lower front teeth, while the central front teeth pressure-sensitive element 60b and the right front teeth pressure-sensitive element 60c constitute the other pair of front teeth pressure-sensitive unit 64b that detects the occlusal force of the right pair of upper and lower front teeth. In other words, in this embodiment, the two pair of front teeth pressure-sensitive units 64a, 64b share the central front teeth pressure-sensitive element 60b.

[0056] The molar detection region 56 (pair of molar pressure-sensing units 58) consisting of the four molar pressure-sensing elements 54a-54d has a smaller width in the left-right direction than the front tooth detection region 62 (pair of front tooth pressure-sensing units 64a, 64b) consisting of the three front tooth pressure-sensing elements 60a-60c. The molar detection region 56 having a smaller width is located closer to the tip of the tapered measuring portion 12 than the front tooth detection region 62 having a larger width.

[0057] In this embodiment, as shown in Fig. 2, a guard layer 66 is superimposed on and fixed to the lower surface of the second electrode layer 22. As also shown in Fig. 6, the guard layer 66 has a structure in which a third conductive portion 70 made of a conductive material is formed on the upper surface of an electrically insulating third substrate portion 68. The third substrate portion 68 is preferably made of the same material as the first and second substrate portions 24, 40, and the third conductive portion 70 is preferably made of the same material as the first and second conductive portions 26, 42.

[0058] The third substrate portion 68 has a front end portion and a front-to-rear intermediate portion that constitute the measurement portion 12 and intermediate portion 16 of the oral cavity pressure sensor sheet 10, which have substantially the same shape and size as the first and second substrate portions 24, 40 when viewed in the vertical direction. The rear end portion of the third substrate portion 68 has a shape that substantially corresponds to the left end portion of the connection support portion 14 of the oral cavity pressure sensor sheet 10 when viewed in the vertical direction. The rear end portions of the first to third substrate portions 24, 40, 68 of this embodiment are arranged side by side in the left-right direction without overlapping each other, and are combined with each other in the left-right direction to constitute the connection support portion 14.

[0059] The third conductive portion 70 integrally includes a third terminal portion 72 provided at the rear end portion of the third substrate portion 68, a guard electrode portion 74 provided at the front end portion of the third substrate portion 68, and a third wiring portion 76 that electrically connects the third terminal portion 72 and the guard electrode portion 74. The guard electrode portion 74 has a shape and size that allows it to cover the lower portions of the four molar pressure sensing elements 54a-54d and the three anterior tooth pressure sensing elements 60a-60c. The guard electrode portion 74 of this embodiment has a shape and size that allows it to be provided over substantially the entire measurement portion 12 of the oral cavity pressure sensor sheet 10.

[0060] The third terminal 72 is connected to a ground terminal provided on the control device 38, and the potential of the guard electrode 74 is set to 0. As a result, when the measurement portion 12 of the oral cavity pressure sensor sheet 10 is inserted into the oral cavity of the subject, even if the subject's tongue touches the underside of the measurement portion 12, the guard electrode 74 prevents changes in the capacitance of the back teeth pressure-sensing elements 54a-54d and the front teeth pressure-sensing elements 60a-60c due to the tongue contact. This reduces errors in the detection results of occlusal force, allowing for more accurate measurement of the magnitude of occlusal force.

[0061] The third substrate portion 68 of the guard layer 66 is adhered to the second substrate portion 40 of the second electrode layer 22 with an adhesive 52 in front of and behind the guard electrode portion 74. As a result, the guard electrode portion 74 is disposed in a position that covers the underside of the molar pressure-sensing elements 54a-54d and the anterior tooth pressure-sensing elements 60a-60c. The guard layer 66 is overlaid on the second electrode layer 22 without being fixed thereto in the region where the guard electrode portion 74 is disposed. In this embodiment, the guard layer 66 adhered to the second electrode layer 22, which is a base sheet, in the intermediate portion 16 serves as a reinforcing sheet that increases the deformation rigidity of the intermediate portion 16.

[0062] Additionally, reinforcing material layers 78 are superimposed on the upper and lower outer surfaces of the back tooth pressure-sensing elements 54a-54d and the front tooth pressure-sensing elements 60a-60c. The reinforcing material layer 78 is in the form of a sheet or film, and has greater bending deformation rigidity with respect to input in the thickness direction than the dielectric layer 18. The reinforcing material layer 78 has a thickness dimension greater than that of the first and second substrate portions 24, 40 of the first and second electrode layers 20, 22, and has greater bending deformation rigidity with respect to input in the thickness direction than the first and second substrate portions 24, 40. The reinforcing material layer 78 is preferably made of a hard synthetic resin such as polyethylene terephthalate (PET), polypropylene, or polyamide, but may also be made of a metal such as stainless steel or titanium.

[0063] The reinforcing material layers 78 are provided independently for the back tooth pressure sensing elements 54a-54d and the front tooth pressure sensing elements 60a-60c. Therefore, the reinforcing material layers 78 superimposed on the pressure sensing elements 54a-54d, 60a-60c are capable of relative displacement independently of each other at least in the vertical direction. In this embodiment, since the back tooth pressure sensing elements 54a-54d and the front tooth pressure sensing elements 60a-60c are each substantially square when viewed in the vertical direction, the reinforcing material layers 78 are also substantially square in shape to correspond thereto.

[0064] Additionally, buffers 80 are superimposed on the upper and lower outer surfaces of the reinforcing material layer 78. The buffers 80 are flexible members compressible and deformable in the thickness direction and are provided, for example, to prevent discomfort and toothache when biting down on the oral pressure sensor sheet 10. The buffers 80 are formed of, for example, rubber or synthetic resin elastomer. To achieve high buffering performance, the buffers 80 are preferably foams with numerous closed or open cells, or sponges with a spongy structure, with foams being preferred. In this embodiment, a pair of buffers 80a, 80a is provided across the four molar pressure-sensing elements 54a-54d so as to cover both the upper and lower sides of the molar detection region 56, and a pair of buffers 80b, 80b is provided across the three front tooth pressure-sensing elements 60a-60c so as to cover both the upper and lower sides of the front tooth detection region 62. However, the buffer may be provided independently for each pressure-sensitive element, or one buffer may cover both the molar detection area 56 and the front tooth detection area 62.

[0065] In the oral cavity pressure sensor sheet 10 constructed as described above, the measurement portion 12, which includes the detection region for back teeth 56 and the detection region for front teeth 62, is inserted into the oral cavity of the person to be measured. When inserting the oral cavity pressure sensor sheet 10 into the oral cavity, for example, the mark 28 provided at the rear end of the measurement portion 12 can be used to determine the orientation and position of the measurement portion 12 in the oral cavity.

[0066] When the measurement portion 12 is inserted into the oral cavity, the intermediate portion 16 extends from the inside to the outside of the oral cavity. Because the intermediate portion 16 is plate-shaped, its deformation rigidity in the width and length directions is greater than its deformation rigidity in the thickness direction. Furthermore, the first and second electrode layers 20, 22 and the dielectric layer 18 are fixed to each other at the intermediate portion 16, thereby increasing the deformation rigidity of the intermediate portion 16 in the width and length directions. This allows the measurement portion 12 to be stably supported by grasping the intermediate portion 16 when inserting the measurement portion 12 into the oral cavity. Furthermore, by pressing the intermediate portion 16 against the corners of the mouth in the width direction and spreading it, the oral pressure sensor sheet 10 can be inserted into the oral cavity from the side. In particular, in this embodiment, the first and second electrode layers 20, 22 and the dielectric layer 18 are bonded to each other at the intermediate portion 16 using the adhesive 52. The reinforcing effect of the hardened adhesive 52 facilitates ensuring the rigidity of the intermediate portion 16.

[0067] By making the length of the intermediate part 16 connecting the measuring part 12 and the connection support part 14 30 mm or more, when the measuring part 12 is inserted into the oral cavity of the person being measured, the control device 38 attached to the connection support part 14 is sufficiently far from the face of the person being measured, making it unlikely to cause discomfort to the person being measured. In addition, by making the length of the intermediate part 16 connecting the measuring part 12 and the connection support part 14 100 mm or less, excessive lengthening of the oral pressure sensor sheet 10 is prevented.

[0068] When measuring the occlusal force caused by the occlusion of a pair of upper and lower molars, the molar detection area 56 is positioned between the pair of molars. When the subject bites the measurement portion 12 of the oral cavity pressure sensor sheet 10 with the pair of molars, an occlusal force is applied to the pair of molar pressure-sensing units 58 of the molar detection area 56. This causes the first molar electrodes 32a, 32b and the second molar electrodes 46a, 46b to approach each other, which compresses and deforms the dielectric layer 18, changing the capacitance values ​​of the molar pressure-sensing elements 54a-54d that make up the pair of molar pressure-sensing units 58. The change in capacitance value of the molar pressure-sensing elements 54a-54d is detected by the control device 38 connected to the first and second terminals 30, 44, and the magnitude of the occlusal force of the pair of upper and lower molars is measured by the control device 38 through signal amplification, noise removal, and calculation of the occlusal force based on the change in capacitance value.

[0069] In the oral cavity pressure sensor sheet 10, the pair of molar pressure-sensing units 58 are composed of four molar pressure-sensing elements 54a-54d, and the occlusal force of the pair of molars is detected at four separate locations by the four molar pressure-sensing elements 54a-54d. This improves the ability of the pair of molar pressure-sensing units 58 to follow the irregularities of the occlusal surfaces of the molars, compared to when the occlusal force of the pair of molars is detected by a pair of molar pressure-sensing units composed of only one pressure-sensing element. As a result, unintended tilt or deformation of the molar pressure-sensing elements 54 due to the irregularities of the occlusal surfaces of the molars is prevented, improving the accuracy of occlusal force detection.

[0070] The four molar pressure-sensing elements 54a-54d that make up the pair of molar pressure-sensing unit 58 are arranged in a row, two on each of the front, back, left, and right, so as to form a substantially square overall. This makes it easier for the molars to be positioned across the four molar pressure-sensing elements 54a-54d, as shown by the dashed-dotted lines in Fig. 1, and the occlusal force of the pair of molars can be detected by the four molar pressure-sensing elements 54a-54d.

[0071] When measuring the occlusal force caused by the bite of two pairs of upper and lower front teeth, the front teeth detection area 62 is positioned between the upper and lower pairs of front teeth. When the subject bites the measurement portion 12 of the oral cavity pressure sensor sheet 10 with their front teeth, occlusal force is applied to the pair of front teeth pressure-sensing portions 64a, 64b of the front teeth detection area 62. This causes the first front tooth electrode 34 and the second front tooth electrodes 48a-48c to approach each other, which compresses and deforms the dielectric layer 18, changing the capacitance values ​​of the front tooth pressure-sensing elements 60a-60c that make up the pair of front teeth pressure-sensing portions 64a, 64b. The change in capacitance value of the front tooth pressure-sensing elements 60a-60c is detected by the control device 38 connected to the first and second terminals 30, 44, and the magnitude of the occlusal force of the two pairs of upper and lower front teeth is measured by various calculation processes of the control device 38.

[0072] In the oral cavity pressure sensor sheet 10, the pair of front teeth pressure-sensing units 64a, 64b that detect the occlusal force of two pairs of front teeth are composed of three front teeth pressure-sensing elements 60a-60c. The occlusal force of one pair of front teeth is detected by the two front teeth pressure-sensing elements 60a, 60b at two separate locations, and the occlusal force of another pair of front teeth is detected by the two front teeth pressure-sensing elements 60b, 60c at two separate locations. This improves the ability of the pair of front teeth pressure-sensing units 64 to follow the irregularities of the occlusal surfaces of the front teeth compared to when the occlusal force of a pair of front teeth is detected by a pair of front teeth pressure-sensing units composed of only one pressure-sensing element. As a result, unintended tilt or deformation of each front teeth pressure-sensing element 60 due to the irregularities of the occlusal surfaces of the front teeth is prevented, improving the accuracy of occlusal force detection.

[0073] The three front tooth pressure-sensing elements 60a-60c constituting the pair of front tooth pressure-sensing units 64, 64 are arranged side by side. This allows the front teeth to easily straddle the three front tooth pressure-sensing elements 60a-60c, as shown by the dashed-dotted lines in Fig. 1, and the occlusal force of the two pairs of front teeth (central incisors) can be detected by the three front tooth pressure-sensing elements 60a-60c. Because the occlusal surfaces of the front teeth are smaller than those of the molars, four molar pressure-sensing elements 54a-54d were provided for one pair of molars. However, three front tooth pressure-sensing elements 60a-60c are provided for the two pairs of front teeth. This reduces the number of pressure-sensing elements, improving mass productivity and reducing the load on the calculation process, while still ensuring sufficient conformance to the occlusal surface irregularities.

[0074] Since the oral pressure sensor sheet 10 has both a detection area 56 for back teeth and a detection area 62 for front teeth in the measurement portion 12, it can be used to measure both the bite force of back teeth and the bite force of front teeth.

[0075] Moreover, the molar detection region 56, which has a relatively small width in the left-right direction corresponding to the shape of the pair of molars, is located closer to the tip (front) than the front tooth detection region 62, which has a large width in the left-right direction corresponding to the shape of the two pairs of front teeth. This allows the measurement part 12, which is provided with both the molar detection region 56 and the front tooth detection region 62, to have a tapered shape that decreases in width toward the tip, making it easier to insert the measurement part 12 into the oral cavity of the person being measured.

[0076] Furthermore, the detection area 56 for back teeth, which needs to be inserted further back into the oral cavity than the detection area 62 for front teeth, is positioned closer to the tip of the measurement part 12 for insertion into the oral cavity than the detection area 62 for front teeth. This eliminates the need to insert the measurement part 12 excessively deep into the oral cavity of the person being measured, thereby reducing the burden on the person being measured when measuring occlusal force.

[0077] In the four pressure-sensing elements 54a to 54d for back teeth and the three pressure-sensing elements 60a to 60c for front teeth, the electrodes 32, 34, 46, 48 are all overlaid on the dielectric layer 18 without being fixed thereto. This prevents the dielectric layer 18 from being constrained by the electrodes 32, 34, 46, 48, which are harder than the dielectric layer 18, thereby preventing an effect on detection accuracy.

[0078] In addition, flexible electrodes 32, 34, 46, 48 are employed that can follow the compressive deformation of the dielectric layer 18. Therefore, the deformation rigidity of the electrodes 32, 34, 46, 48 is unlikely to affect the transmission of occlusal force to the dielectric layer 18, and detection areas 56, 62 that easily follow the unevenness of the occlusal surfaces of the teeth can be realized by the back tooth pressure-sensitive elements 54a-54d and front tooth pressure-sensitive elements 60a-60c formed by the strip-shaped electrodes 32, 34, 46, 48. Furthermore, because the back tooth pressure-sensitive elements 54a-54d and front tooth pressure-sensitive elements 60a-60c have a flexible structure up to the electrodes 32, 34, 46, 48, anxiety and pain experienced by the subject when biting down on these pressure-sensitive elements 54, 60 are reduced.

[0079] Both the front and back surfaces of the pressure-sensing parts 58 for the molars and the pressure-sensing parts 64, 64 for the front teeth are covered with a reinforcing material layer 78. Therefore, occlusal force is not applied directly from the teeth to the flexible first and second conductive parts 26, 42 and the dielectric layer 18, but is applied indirectly and dispersedly via the reinforcing material layer 78. This prevents damage to the first and second conductive parts 26, 42 and the dielectric layer 18 due to the concentrated action of occlusal force.

[0080] Furthermore, the reinforcing material layer 78 is provided independently for each of the back tooth pressure-sensitive elements 54a-54d and the front tooth pressure-sensitive elements 60a-60c. Therefore, even if the reinforcing material layer 78, which has higher rigidity than the dielectric layer 18, is provided on each of the pressure-sensitive elements 54, 60, it is unlikely to affect the accuracy of occlusal force detection.

[0081] Furthermore, since the surface of the reinforcing material layer 78 is covered with a flexible cushioning material 80 that is compressible and deformable, feelings of anxiety, discomfort, toothache, etc. caused by the teeth coming into direct contact with the hard reinforcing material layer 78 are prevented.

[0082] The oral pressure sensor sheet 10 may be disposable and discarded after a single use, but is preferably reused. Because the measurement portion 12 of the oral pressure sensor sheet 10 is inserted into the oral cavity during use, it is desirable to attach a disposable cover to cover the measurement portion 12 and the intermediate portion 16, particularly when the sheet is used frequently, from the viewpoint of hygiene and preventing contamination of the oral pressure sensor sheet 10. The cover is preferably a thin, flexible film-like bag that does not affect the measurement of occlusal force, and is made of, for example, polyethylene, polystyrene, or polyvinylidene chloride. It is also possible to provide an elastic layer on the cover to improve or adjust the sensation during occlusion.

[0083] In the first embodiment described above, a structure in which both the back tooth detection area 56 and the front tooth detection area 62 are provided in the measurement portion 12 is exemplified, but the measurement portion 12 may be provided with only the back tooth detection area 56 or only the front tooth detection area 62.

[0084] As a second embodiment of the present invention, a specific example of a structure in which only a molar detection region 56 is provided in the measurement portion 12 is shown in Figure 7. Note that, since the basic configuration of this embodiment is substantially the same as that of the first embodiment, the same reference numerals are used in Figure 7 for the components corresponding to those of the first embodiment, and detailed descriptions thereof will be omitted. Furthermore, in this embodiment, the planar structure (Figure 1), dielectric layer structure (Figure 3), first electrode layer structure (Figure 4), second electrode layer structure (Figure 5), and guard layer structure (Figure 6) of the oral cavity pressure sensor sheet 10 according to the first embodiment can all be understood as a structure excluding the front teeth detection mechanism, and therefore drawings corresponding to these Figures 1, 3, 4, 5, and 6 will be omitted.

[0085] 7, the oral cavity pressure sensor sheet 10' according to the second embodiment is located on the distal end side of the measurement portion 12 to be inserted into the oral cavity and includes a molar detection region 56. In the molar detection region 56, as in the first embodiment, the first molar electrodes 32a, 32b and the second molar electrodes 46a, 46b supported by the first substrate portion 24 and the second substrate portion 40 are superimposed on both the top and bottom of the dielectric layer 18, thereby constituting four molar pressure-sensing elements 54a-d.

[0086] Furthermore, in the molar detection region 56, as in the first embodiment, a guard electrode portion 74 is supported by the third substrate portion 68 and disposed so as to cover the outer side (lower side) of the second molar electrode 46. In the intermediate portion 16, the first substrate portion 24 and the second substrate portion 40 are bonded to the dielectric layer 18 to improve strength or rigidity. In the measurement portion 12, the first molar electrodes 32a, 32b and the second molar electrodes 46a, 46b are not bonded but are loosely superimposed on the dielectric layer 18. The first molar electrodes 32a, 32b are superimposed on the upper surface of the dielectric layer 18 via a gap 53 and the first substrate portion 24. The guard electrode portion 74 may be bonded to the second substrate portion 40 supporting the second molar electrodes 46a, 46b, but is preferably loosely superimposed to avoid excessive restraint.

[0087] Furthermore, reinforcement layers 78, 78 are superimposed on the first molar electrodes 32a, 32b and the second molar electrodes 46a, 46b, positioned on the outer sides in the up-down direction. In particular, in this embodiment, the reinforcement layer 78 arranged on the upper side in Fig. 7 is a single reinforcement layer 78 that extends to a size sufficient to entirely cover the two first molar electrodes 32a, 32b arranged in the molar detection region 56, and the reinforcement layer 78 arranged on the lower side in Fig. 7 is a single reinforcement layer 78 that extends to a size sufficient to entirely cover the two second molar electrodes 46a, 46b arranged in the molar detection region 56.

[0088] That is, in the present embodiment, in the four molar pressure-sensitive elements 54a to 54d provided in the molar detection region 56, a plurality of upper and lower electrodes (first molar electrodes 32a and 32b and second molar electrodes 46a and 46b) are provided so as to cover them from the outside, and one reinforcing material layer 78 is provided on each of the upper and lower sides. In the present embodiment, the upper reinforcing material layer 78 is fixed to the first molar electrodes 32a and 32b, while the lower reinforcing material layer 78 is fixed to the third substrate portion.

[0089] In addition, on the outer sides of these upper and lower reinforcing material layers 78 and 78, buffer bodies 80 and 80 are arranged and fixed so as to cover the entire surface, similar to the first embodiment.

[0090] In the molar pressure-sensitive elements 54a to 54d configured as described above, particularly in the present embodiment, the thickness dimension Tb of the reinforcing material layer 78 is made larger than the thickness dimension Ta of the intermediate layer, so that Ta < Tb. Further, the thickness dimension Tb of the reinforcing material layer 78 is made larger than the thickness dimension t of the first substrate portion 24 and the second substrate portion 40, so that t < Tb. On the other hand, the thickness dimension Tc of the buffer body 80 is made larger than the thickness dimension Tb of the reinforcing material layer 78, so that Tc > Tb.

[0091] Although the dimensions of each member are not limited, as a preferred example for reference, the thickness dimension of the reinforcing material layer 78 is preferably set within the range of 0.5 to 5 mm, and more preferably within the range of 1 to 3 mm.

[0092] In the oral pressure sensor sheet 10' of the present embodiment having such a structure, similar to the first embodiment, it is inserted into the oral cavity from the tip side and used, and by biting the molar detection region 56 with a specific pair of molars, the biting force of the pair of molars can be detected by the molar pressure-sensitive elements 54a to 54d.

[0093] Here, particularly in this embodiment, the biting force exerted on each of the electrode layers 32a, 32b and 46a, 46b constituting the plurality of molar pressure-sensitive elements 54a to 54d is dispersed and exerted by the reinforcing material layer 78 arranged across the plurality of molar pressure-sensitive elements 54a to 54d. Therefore, it becomes possible to measure the biting force with higher reliability while effectively preventing damage to the electrodes due to uneven load or the like.

[0094] Particularly, by making the reinforcing material layer 78 thicker (Ta < Tb) than the dielectric layer 18, the dispersing action of the biting force by the reinforcing material layer 78 is more effectively exerted. Even when the electrodes 32, 46 and the dielectric layer 18 are thinner or have lower rigidity than the reinforcing material layer 78, damage to these electrodes 32, 46 and the dielectric layer 18 can be effectively prevented. Also, by making the reinforcing material layer 78 thicker than the dielectric layer 18 to increase the deformation rigidity, it becomes possible to act on the biting force exerted on the dielectric layer 18 through the reinforcing material layer 78 so as to suppress shear deformation and efficiently generate compressive deformation, which also leads to an improvement in measurement accuracy.

[0095] Also, by making the reinforcing material layer 78 thicker than the first substrate portion 24 and the second substrate portion 40 to increase the deformation rigidity, while suppressing the thickness dimension t of the first substrate portion 24 and the second substrate portion 40 to improve the measurement sensitivity, etc., it becomes possible to effectively prevent damage to the base sheet by the reinforcing material layer.

[0096] Furthermore, by making the thickness dimension Tc of the buffer body 80 larger than the thickness dimension Tb of the reinforcing material layer 78 and ensuring it sufficiently, the effect of improving the biting feeling when exerting the biting force on the hard reinforcing material layer 78 is effectively exerted.

[0097] Although several embodiments of the present invention have been described above in detail, the present invention is not limited to these specific descriptions. For example, in the first embodiment, for ease of understanding, the two detection areas are described as the molar detection area 56 and the front tooth detection area 62. However, it is also possible to measure the occlusal force of the canine by biting the molar detection area 56 or the front tooth detection area 62 with the canine located between the front and molar teeth. Also, the molar detection area 56 may be bitten with the front teeth to measure the occlusal force. In other words, the molar detection area 56 is suitable for detecting the occlusal force of the molar teeth, and the front tooth detection area 62 is suitable for detecting the occlusal force of the front teeth. However, it is also possible to measure the occlusal force by biting the molar detection area 56 with teeth other than the molar teeth, or by biting the front tooth detection area 62 with teeth other than the front teeth. Furthermore, in addition to or instead of the molar detection area 56 and the front tooth detection area 62, a detection area for an intermediate tooth for measuring the occlusal force of a canine or the like may be provided.

[0098] The number of pressure-sensitive elements constituting the pressure-sensitive unit for a pair of teeth is not particularly limited as long as it is plural. Increasing the number of pressure-sensitive elements constituting the pressure-sensitive unit for a pair of teeth improves the ability to follow unevenness, thereby reducing detection errors due to unevenness and enabling more accurate measurement of occlusal force.

[0099] The arrangement, shape, size, and number of electrodes constituting each pressure-sensitive element are not particularly limited and are appropriately determined depending on the number of pressure-sensitive elements constituting the pair of teeth pressure-sensing unit. However, since multiple pressure-sensitive elements are arranged in the area where a pair of teeth occlude, as described above, the size of each pressure-sensitive element can be appropriately adjusted and set depending on the type and size of the tooth for which occlusal force is to be detected (e.g., primary tooth, permanent tooth, front tooth (incisor), canine tooth, back tooth (molar), etc.). For example, the size of each pressure-sensitive element is preferably set within the range of 1 mm square to 10 mm square, and the size of each pressure-sensitive element can be set within the range of 1 mm square to 5 mm square. Furthermore, since the oral pressure sensor sheet is inserted into the mouth, the width of the sensor sheet can be appropriately adjusted and set depending on the size of the subject's mouth. For example, the size of each pressure-sensitive element may be varied as needed, such as for children and adults, to provide a range of products with different sensor sheet widths. In particular, when measuring the occlusal pressure of back teeth, it is preferable to set the width dimension of the middle part from the tip that is inserted into the oral cavity to within a range of 10 to 30 mm, taking into consideration that the device will be inserted diagonally from the side into the subject's mouth.

[0100] Furthermore, while it is desirable for the pressure-sensitive element to be compressible and deformable, it may also be, for example, a piezoelectric element or a load cell that does not undergo compressive deformation. Furthermore, the pressure-sensitive element having a structure in which flexible electrodes are superimposed on both sides of a compressible and deformable intermediate layer is not limited to the capacitance type that detects occlusal force based on changes in capacitance as shown in the above embodiment. Specifically, for example, the pressure-sensitive element may be an electrical resistance type in which the intermediate layer is made of a conductive elastomer in which a conductive filler is mixed with an electrically insulating binder, and the occlusal force is detected based on changes in electrical resistance caused by the compressive deformation of the intermediate layer. Alternatively, the pressure-sensitive element may be a piezoelectric type in which the intermediate layer is made of a piezoelectric elastomer in which piezoelectric particles are mixed with a binder, and the occlusal force is detected based on the piezoelectricity generated by the piezoelectric particles.

[0101] In addition, in the detection area, it is desirable that the dielectric layer and the electrode as an intermediate layer are overlapped without being fixed to each other as shown in the above embodiment, but even if they are not fixed to each other, it is sufficient that at least one of the electrodes is not fixed to the dielectric layer, and the dielectric layer and the electrode may be fixed to each other in the detection area. Furthermore, it is desirable that the dielectric layer as a reinforcing sheet and the electrode layer as a base sheet are fixed to each other in their intermediate portions for the purpose of ensuring strength in the width direction, but the dielectric layer and the electrode layer may be unfixed to each other in their intermediate portions.

[0102] Furthermore, the reinforcing material layer 78 and the buffer body 80 shown in the above embodiment may be omitted, and the guard layer 66 is not essential.

[0103] Furthermore, the oral pressure sensor sheet 10 shown in the above embodiment is in the form of a longitudinal sheet extending linearly in the front-to-back direction, but it may also be, for example, bent in an L-shape when viewed from above or below, or curved in an arc.

[0104] Furthermore, the relative relationships regarding the thickness dimensions of the dielectric layer 18, reinforcing material layer 78, buffer 80, and first and second substrate portions 24, 40 shown in the oral pressure sensor sheet 10' of the second embodiment can also be suitably applied to the oral pressure sensor sheet 10 of the first embodiment. [Explanation of symbols]

[0105] 10 Oral pressure sensor sheet (first embodiment) 10' Oral pressure sensor sheet (second embodiment) 12 Measuring part 14 Connection support part 16 Middle part 18 Dielectric layer (intermediate layer, reinforcing sheet) 20 First electrode layer (base sheet) 22 Second electrode layer (base sheet) 24 First board part 26 First conductive part 28 Landmark 30(30a~30c) First terminal part 32 (32a, 32b) First molar electrode (electrode) 34 First anterior electrode (electrode) 36a~36c First wiring section 38 Control Device 40 Second board section 42 Second conductive part 44(44a~44c) Second terminal part 46 (46a, 46b) Second molar electrode (electrode) 48 (48a-48c) Second front tooth electrode (electrode) 50a~50c 2nd wiring section 51 Positioning hole 52 Adhesive 54 (54a to 54d) Pressure-sensitive element for molars (pressure-sensitive element) 56 Molar detection area (detection area) 58 Pressure-sensing part for a pair of molars (pressure-sensing part for a pair of teeth) 60 (60a-60c) Pressure-sensitive element for front teeth (pressure-sensitive element) 62 Front teeth detection area (detection area) 64 (64a, 64b) Pressure-sensing unit for a pair of front teeth (pressure-sensing unit for a pair of teeth) 66 Guard layer (reinforcement sheet) 68 Third board section 70 Third conductive part 72 Third terminal section 74 Guard electrode part 76 Third wiring section 78 Reinforcement layer 80(80a,80b) Buffer

Claims

1. An oral pressure sensor sheet having a measuring portion on the tip side that is inserted into the oral cavity, The measuring portion has a detection area to which a occlusal force due to the occlusion of one or two pairs of upper and lower teeth is applied, The oral cavity pressure sensor sheet has a pair of teeth pressure-sensing section that detects the occlusal force of a pair of upper and lower teeth in the detection area, and has multiple pressure-sensing elements that detect pressure arranged in the sheet surface direction.

2. The oral cavity pressure sensor sheet according to claim 1 , wherein the pressure-sensitive element has an electrode that is not adhered to and overlaps the compressible intermediate layer.

3. 3. The oral cavity pressure sensor sheet according to claim 1, wherein the pressure-sensitive element has a structure in which flexible electrodes are arranged on both sides of a compressible intermediate layer.

4. An oral pressure sensor sheet as described in claim 3, wherein a reinforcing material layer having greater deformation rigidity than the intermediate layer is superimposed on each of the multiple pressure-sensitive elements on the outside of the electrodes arranged on both sides of the intermediate layer, and is provided across each of the multiple pressure-sensitive elements.

5. The pressure-sensitive part for a pair of teeth is provided with compressible and deformable buffer bodies superimposed on the outermost sides of the reinforcing material layers disposed on both sides of the intermediate layer in a size that entirely covers the reinforcing material layers, and 5. The oral cavity pressure sensor sheet according to claim 4, wherein the thickness of the reinforcing material layer is greater than the thickness of the intermediate layer and less than the thickness of the buffer body.

6. the electrodes are fixedly held by base sheets disposed on both sides of the intermediate layer, 6. The pressure sensor sheet for an oral cavity according to claim 5, wherein the thickness of the reinforcing material layer is greater than the thickness of the base sheet.

7. 4. The oral cavity pressure sensor sheet according to claim 3, wherein a reinforcing layer having a deformation rigidity greater than that of the intermediate layer is provided for each of the pressure-sensitive elements.

8. a connection support part having a plurality of electrical contacts for external connection is provided on the base end side, and the connection support part and the measuring part are connected by an intermediate part; a base sheet is provided on both the front and back sides so as to extend over an area from the measurement portion through the intermediate portion to the connection support portion; A pressure sensor sheet for the oral cavity as described in claim 1 or 2, wherein in the intermediate portion which is positioned inside and outside the oral cavity when the measurement portion is inserted into the oral cavity, the base sheets on both the front and back sides are fixed with a reinforcing sheet sandwiched between them.

9. The measuring portion has a tapered shape with a tip end side having a smaller left-right width dimension than a base end side, An oral pressure sensor sheet as described in claim 1 or 2, wherein the measurement portion has a detection area for back teeth with a smaller left-right width dimension positioned closer to the tip than the detection area for front teeth with a larger left-right width dimension.

Images