Mandibular movement range measuring scale and method

Abstract

The invention relates to a mandibular movement range measuring scale and method, and belongs to the field of measuring appliances, the mandibular movement range measuring scale comprises a main body and a measuring rod, the main body is provided with a chute along the length, the middle of the measuring rod is connected with the main body through a rotating shaft, the measuring rod and the main body can move along the chute, and the measuring rod can rotate around the rotating shaft; one end of the main body is provided with a first intraoral connector, and the other end is provided with a measuring plate; one end of the measuring rod is connected with the second intraoral connector, the other end is provided with a pointer, and the movement track of the pointer is located in the plane of the measuring plate; scale lines are arranged on the side, facing the pointer, of the measuring plate. Scale marks are arranged on the measuring plate, the measuring rod is installed in the main body sliding groove in a sliding mode through a cylindrical suspension screw fixed to the center of the long axis of the measuring rod, the movement range is transferred to the pointer in an equal proportion mode according to movement and measurement of mandibular teeth, and therefore the movement range of the mandibular teeth in the plane is measured on the measuring plate, and the whole measuring ruler is rotated by 90 degrees. The opening degree can be measured through the same principle.

Description

Technical Field

[0001] The invention relates to the field of oral measurement technology, and in particular to a ruler and method for measuring the range of mandibular motion. Background Art

[0002] As one of the most complex joints in the human body, the flexibility and function of the temporomandibular joint are essential for many activities in daily life, such as chewing, pronunciation, and facial expressions. However, the complexity and high-load use of this joint also make it vulnerable to injury or disease, such as temporomandibular disorders (TMD) and ankylosis, which often lead to limited mouth opening and limited range of mandibular movement, significantly affecting the patient's quality of life. According to many domestic and foreign studies and clinical statistics, TMD and the recovery of mandibular movement function after treatment have become one of the key factors affecting the patient's quality of life. Therefore, for TMD patients and patients who have undergone related surgeries, it is particularly important to accurately evaluate and promote rehabilitation intervention for mandibular movement function.

[0003] When evaluating mandibular movement function, the degree of mouth opening is relatively easy to measure, but the mandibular protrusion and lateral movement distances are difficult to measure accurately with traditional methods due to their complexity and multidimensionality. These movements not only involve the movement of the mandible in the horizontal plane, but are also accompanied by complex movements such as rotation. Therefore, a measurement tool that can fully and accurately capture these movement changes is needed.

[0004] At present, there are many tools for measuring mandibular movement on the market, each of which has its own advantages and disadvantages. For example, some measurement methods based on video recording or three-dimensional motion capture systems, although they can provide highly accurate data, are expensive and complex to operate, and are not suitable for widespread use in daily clinical or home environments. In addition, some simple ruler or protractor tools, although easy to operate and low cost, often have problems such as insufficient accuracy and susceptibility to human errors when measuring complex mandibular movements. The utility model patent with publication number CN217697802U provides a multifunctional oral organ trainer, in which the measuring ruler changes position with the patient's mouth opening, and the patient's mouth opening can be observed through the scale indicated by the card mark, realizing the in vitro transfer of the muscle motion range value to facilitate measurement, but focusing on the opening and closing training of the lip muscles. Another invention patent with publication number CN103565439A provides a mandibular protrusion distance measuring device to determine the accurate size range of mandibular protrusion, but it focuses on the use of mandibular advancement oral appliances for the treatment of snoring and mild to moderate sleep apnea syndrome, and is not suitable for measuring the range of mandibular movement in different directions.

[0005] In view of this, it is particularly important to invent a mandibular range of motion measuring ruler that has high measurement accuracy, is easy to operate, and has reasonable cost. This tool should be able to accurately measure the movement distance of the mandible in different directions (such as protrusion, lateral movement, opening and closing the mouth), provide objective and quantitative evaluation basis for clinicians, and also facilitate patients to conduct self-monitoring at home, thereby promoting the recovery of mandibular movement function and improving the quality of life.

[0006] Invention patent content In view of the above problems, the purpose of the present invention is to provide a mandibular motion range measuring ruler to solve the problem that the existing simple measuring devices cannot accurately measure the mandibular opening and closing, protrusion and lateral motion range.

[0007] In order to achieve the above-mentioned purpose, the patent of the present invention adopts the following technical scheme: a mandibular motion range measuring ruler, including a main body and a measuring rod, a slide groove is provided along the length of the main body, the middle part of the measuring rod is connected to the main body through a rotating shaft, the measuring rod and the main body can move along the slide groove, and the measuring rod can rotate around the rotating shaft; a first intra-oral connector is provided at one end of the main body, and a measuring plate is provided at the other end; one end of the measuring rod is connected to the second intra-oral connector, and a pointer is provided at the other end, and the moving track of the pointer is located in the plane of the measuring plate; a scale line is provided on the side of the measuring plate facing the pointer.

[0008] Further, the tip of the pointer contacts the side of the measuring plate with scale lines, and the pointer is perpendicular to the measuring plate.

[0009] Furthermore, the scale lines include longitudinal scale lines and transverse scale lines that are perpendicular to each other, and the longitudinal scale lines are parallel to the length direction of the main body.

[0010] Furthermore, the rotating shaft is a suspension knob, the main body diameter of the suspension knob is smaller than the slide slot, the end cover diameter of the suspension knob is larger than the slide slot, and a nut is arranged on the main body of the suspension knob.

[0011] Furthermore, the first intra-oral connector and the second intra-oral connector have the same structure, including a base fixed on the main body or the measuring rod, a patch adhered to one side of the tooth surface, and a connecting rod between the base and the patch, and the connecting rod is a universal joint connection structure.

[0012] Furthermore, a detachable slot device is provided on the pointer, and the slot device includes an adjustable clamp and a slot, and the clamp can be loosened by rotating or sliding.

[0013] Furthermore, a partition is fixedly arranged in the middle of the suspension knob, and nuts are connected at both ends.

[0014] Furthermore, the pointer adopts a pen tip.

[0015] Furthermore, the distance between two adjacent scale lines on the measuring plate is 0.5 mm, 1 mm or 1.5 mm.

[0016] At the same time, the present invention provides a method for measuring the range of mandibular motion. Based on the mandibular motion range measuring ruler, the first intraoral connector is glued to the mandibular tooth surface, the second intraoral connector is glued to the mandibular tooth surface, and the person being tested is instructed to move the mandible forward, leftward, rightward, leftward, and rightward; the corresponding range of motion values ​​are read out through a measuring plate; Rotate the measuring ruler 90° with the long axis as the rotation axis, and stick the first intraoral connector to the mandibular tooth surface, and stick the second intraoral connector to the mandibular tooth surface. At this time, the pointer will point to an initial position on the measuring plate. Ask the person to open his mouth wide, and read the final position of the maximum mandibular opening on the measuring plate when the mouth is opened. The distance between the initial position and the final position is the value of the mouth opening.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects: The mandibular motion range measuring ruler of the present invention transfers the distance that is difficult to measure inside the mouth to the outside of the mouth through a device for more intuitive and accurate measurement. By fixing a measuring plate on the main body, the front end of the outer edge contour extends forward in an arc shape, and scale lines are set on the measuring plate. The measuring rod is slidably installed in the main body slide groove by a cylindrical suspension screw fixed at the center of the long axis of the measuring rod. According to the movement of the mandibular teeth, the motion range is proportionally transferred to the pointer, so that the motion range of the mandible in the plane is measured on the measuring plate. The entire measuring ruler is rotated 90°, and the mouth opening degree can be measured by the same principle, which is beneficial to the general examination of mandibular movement in clinical practice and the clinical research on functional rehabilitation intervention of patients with mandibular movement disorders.

[0018] Furthermore, the tip of the pointer contacts the side of the measuring plate with the scale lines, and the pointer is perpendicular to the measuring plate, and can clearly draw a track on the measuring plate to indicate the measured value.

[0019] Furthermore, the scale lines include longitudinal scale lines and transverse scale lines that are perpendicular to each other, and the longitudinal scale lines are parallel to the length direction of the main body, thereby realizing integrated measurement in different directions.

[0020] Furthermore, the rotating shaft is a suspension knob, the main body diameter of the suspension knob is smaller than the slide slot, and the end cover diameter of the suspension knob is larger than the slide slot. A nut is arranged on the main body of the suspension knob, so that the main body and the measuring rod can slide relatively easily and can be tightened, and can also realize relative movement with resistance between the main body and the measuring rod, so that the patient can clearly feel the movement between the main body and the measuring rod.

[0021] Furthermore, the first intra-oral connector and the second intra-oral connector have the same structure, including a base fixed on the main body or the measuring rod, a patch adhered to one side of the tooth surface, and a connecting rod between the base and the patch. The connecting rod is a universal joint connection structure, which can achieve rotation without generating translation, thereby improving measurement accuracy.

[0022] Furthermore, a detachable slot device is provided on the pointer, and the slot device includes an adjustable clamp and a slot, and the clamp can be loosened by rotating or sliding.

[0023] Furthermore, a partition is fixedly provided in the middle of the suspension knob, and nuts are connected at both ends. As a common mechanical component, the suspension knob can control the sliding, rotatable and tight connection between the main body and the measuring rod.

[0024] The present invention uses a device to measure the range of motion of jaw protrusion, retraction and lateral movement, which makes the measurement more convenient and accurate, and greatly improves the measurement efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the three-dimensional structure of the mandibular motion range measuring ruler of the present invention; Figure 2 1 is a schematic diagram of the front view (operator's perspective) of the mandibular motion range measuring ruler of the present invention; Figure 3 is a schematic diagram of the back view (from the patient's perspective) of the mandibular motion range measuring ruler of the present invention; Figure 4 is a schematic side view of the mandibular motion range measuring ruler of the present invention; Figure 5 is a schematic top view of the mandibular motion range measuring ruler of the present invention; Figure 6 This is a partial enlarged schematic diagram of the three-dimensional structure of the mandibular motion range measuring ruler of the present invention. Figure 1 ; Figure 7 This is a partial enlarged schematic diagram of the three-dimensional structure of the mandibular motion range measuring ruler of the present invention. Figure 2 ; In the figure, 1. main body; 2. measuring rod; 3. measuring plate; 4. slide groove; 5. connector in the first port; 6. connector in the second port; 7. sling knob; 8. pointer; 9. scale line; 10. patch; 11. base; 12. connecting rod. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second" and the like are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0028] The specific implementation methods of the present invention are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0029] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 7 As shown, a mandibular motion range measuring ruler provided by the present invention comprises a main body 1 and a measuring rod 2, wherein the measuring rod 2 and the main body 1 are arranged along two parallel planes, the measuring rod 2 and the main body 1 can move along the length direction, the measuring rod 2 can rotate relative to the main body 1, one end of the main body 1 is connected to a first intraoral connector 5, and one end of the measuring rod 2 is connected to a second intraoral connector 6, wherein a measuring plate 3 is arranged at the other end of the main body 1, and scale lines 9 are arranged on the measuring plate 3, the main body 1 is in a long box shape, and a slide groove 4 is arranged on the main body 1 along the length direction, one end of the first intraoral connector 5 is connected to the main body 1, and the other end is used for detachably connecting to the mouth; the measuring plate 3 is connected to the main body 1 through a suspension knob; in the measuring state, the measuring plate 3 is placed above the mandibular dental arch; the front end of the outer edge contour of the measuring plate 3 away from the opening side of the main body 1 extends forward in a semicircular shape with a radius of 6 cm; a plurality of scale lines 9 are arranged on the upper surface of the measuring plate 3, and the scale lines 9 are in a grid shape, and the interval between adjacent grid lines of the scale lines 9 is 1 mm.

[0030] The measuring plate 3 is semicircular, and the scale lines 9 include horizontal and vertical marking lines, wherein the vertical direction refers to the direction parallel to the length of the main body 1, and the horizontal direction is perpendicular to the vertical direction. The measuring plate 3 is fixed to one end of the main body 1, and the measuring plate 3 is embedded in the end of the main body 1 through the bracket slot.

[0031] refer to Figure 6The measuring rod 2 includes a rod body and a pointer 8. The main body 1 is provided with a slide groove 4. A through hole is provided in the middle of the measuring rod 2. The measuring rod 2 is slidably connected with the main body 1 through the sling knob 7 and the slide groove 4 to adjust the track of the pointer 8 at the end of the measuring rod 2 on the measuring plate 3. When the mandible moves, the lower surface of the measuring plate 3 fits with the pointer 8 at the end of the measuring rod 2. The pointer 8 at the end of the measuring rod 2 is a pointer that vertically points to the measuring plate 3 or a pencil is inserted into the card slot.

[0032] The pointer 8 is provided with a detachable slot device, which includes an adjustable clamp and a slot. The adjustable clamp can be loosened by rotating or sliding, and a pencil or a pointer is inserted into the slot and rotated to fix or pull out the pencil or the pointer from the slot.

[0033] The adjustable chuck is designed with two adjustment mechanisms: rotation or sliding. The rotation mechanism may be realized by threads or buckles. By rotating or sliding, the adjustable chuck can be easily loosened to insert the pencil or indicator needle into the slot. It can be tightened by rotating or sliding again to ensure that the pencil or indicator needle is stable and does not fall off. The shape and size of the slot should be able to adapt to a variety of cross-sectional shapes of pencils and indicator needles, such as round and hexagonal. The surface of the slot can be treated with anti-slip treatment, such as sandblasting, texture engraving, etc., to increase the friction between the pencil or indicator needle and the slot to prevent it from slipping during use.

[0034] refer to Figure 7 The front end (patient side) of the measuring rod 2 is provided with a second intraoral connector 6. The first intraoral connector 5 and the first intraoral connector 6 have the same structure, including a base 11 fixed on the main body 1 or the measuring rod 2, a patch 10 pasted to one side of the tooth surface, and a connecting rod 12 between the base 11 and the patch 10. The connecting rod 12 is composed of a freely rotatable spherical top and a fixed arched groove. The arched groove wraps the part of the spherical top so that the main body 1 can rotate within a small range relative to the patch pasted on the tooth surface, increasing the flexibility when measuring the range of mandibular movement. The patch 10 can be bonded to the corresponding disposable tooth surface patch. The disposable tooth surface patch is a disposable environmentally friendly material that is easy to replace, and the patch of the intraoral connector is connected to the base by being stuck in the connector and can be used for a long time.

[0035] The first intra-oral connector 5 and the first intra-oral connector 6 do not generate translational movement when the measuring rod 1 and the main body 1 are flexibly rotated relative to the teeth, thus facilitating detection without affecting accuracy.

[0036] The present invention fixes a measuring plate 3 on a main body 1, and a semicircular measuring plate 3 is extended forward from the front end of the outer edge contour of the measuring plate 3. The measuring rod 2 is placed on one side of the mandibular dentition, and the main body 1 is located on the side of the maxillary dental arch. The person being measured moves the mandible to the longest protrusion and lateral distance. The end cover radius of the suspension knob 7 is greater than the width of the slide groove 4, and the radius of the main body part located between the main body 1 and the measuring rod 2 is slightly smaller than the width of the slide groove 4, so as to reduce the friction between the part and the slide groove as much as possible. The measuring rod 2 can rotate along a plane perpendicular to the suspension knob 7, and the measuring rod 2 can slide in the length direction of the main body 1; the suspension knob 7 is fixed at the center of the measuring rod 2, and the movement trajectory of the mandibular tooth surface with a disposable patch can be proportionally transferred to the pointer 8. When the pointer 8 moves, the longest distance value of the protrusion, retreat and lateral movement of the mandibular teeth can be read on the measuring plate 3, thereby measuring the movement range of the mandible in the plane. Optionally, the pointer 8 is a pen tip, which can be a small pencil tip or a colored fluorescent pen tip. The diameter of the pen tip is as thin as possible and does not exceed the resolution of the scale of the measuring plate.

[0037] Optionally, a partition is fixedly provided in the middle of the suspension knob 7, and nuts are connected at both ends. The nuts can be used to control the tightness of the connection between the suspension knob 7 and the main body 1 and the measuring rod 2, which is convenient for operation.

[0038] The measuring ruler of the present invention can be reused after being sterilized by high-temperature steam.

[0039] It should be noted that the vertical range value (mouth opening) of mandibular movement is of great significance for clinical research. Therefore, the present invention can also be used to measure the range value of mouth opening. For example, the measuring ruler is rotated 90° with the long axis as the rotation axis, the first intra-oral connector 5 is glued to the mandibular tooth surface, and the second intra-oral connector 6 is glued to the mandibular tooth surface. At this time, the pointer 8 will point to an initial position on the measuring plate 3, and the patient is asked to open his mouth wide. Since the base fixed on the measuring rod is composed of a freely rotatable spherical top and a fixed arched groove, the groove wraps around the part of the spherical top, so that the main body can rotate within a small range relative to the patch attached to the tooth surface, thereby increasing the flexibility in measuring the range of mandibular movement. In this way, the final position of the mandibular maximum mouth opening can be read on the measuring plate 3 when the mouth is wide open, and the distance between the initial position and the final position is the value of the mouth opening.

[0040] Since the front end of the measuring plate 3 extends forward in a semicircular shape, it is convenient to set scale lines in a larger range. The upper surface of the measuring plate 3 is provided with a plurality of scale lines 9, which are in a grid shape, and the interval between adjacent grid lines of the scale lines 9 is 1mm, thereby improving the measurement accuracy.

[0041] By changing the direction of the measuring ruler, it can be applied to the amount of mandibular protrusion, left protrusion, right protrusion, left front, right front, up and down movement. According to the longest distance of the mandibular protrusion in each direction, the comparable degree of mandibular activity in different directions can be measured.

[0042] In the present invention, the interval between adjacent scale lines 9 is 1 mm. In other embodiments, the interval between adjacent scale lines 9 may also be other values, for example, 0.5 mm, 1.5 mm.

[0043] The working process of the measuring ruler of the present invention is: When using it, first make sure the patient is in a supine position and relaxed to eliminate the influence of tension on the measurement results. The doctor will guide the patient to relax the mandible and put it naturally in the resting jaw position, which is the natural position of the mandible when it is not subject to external forces, and helps to obtain accurate measurement data. Then, use disposable patches to fix the patient's upper and lower incisors respectively to ensure the stability of the measurement. At this time, the doctor records the initial position of the pointer on the measuring ruler as the reference point for subsequent measurement of the range of mandibular movement.

[0044] During the measurement, the physician places his hand on the chin to first induce the patient's mandible to move forward, drive the measuring ruler to extend forward until the mandible is in the maximum protrusion position, use the mesial of the incisal edge of the maxillary central incisor as a marking point and fix it at the center of the measuring ruler, place the main body 1 on one side of the maxillary dental arch, place the measuring plate 3 in front of the maxillary dentition, and place the measuring rod on one side of the mandibular dental arch. The mandibular teeth drive the measuring rod to slide relative to the main body, and transfer the mandibular movement trajectory to the pointer 8 in proportion. The distance difference between the reading of the measuring ruler at this time and the initial position is recorded to calculate the maximum distance of mandibular protrusion, or the number of grids passed by the mandible during the movement can be directly calculated; then the patient's mandible is asked to retract until the maximum retraction position, and the reading of the measuring ruler is recorded at this time. Similarly, the patient's mandible is asked to move to the left or right until the maximum lateral movement position, and the maximum distance of the front teeth of the measured person protruding forward, to the left, and to the right is recorded according to the reading of the scale line 9, so as to obtain the range of mandibular protrusion, retraction, and lateral movement.

[0045] Then, the vertical upward opening and closing range of motion is measured, the measuring ruler is rotated 90° with the long axis as the rotation axis, the first intra-oral connector 5 is glued to the mandibular tooth surface, the second intra-oral connector 6 is glued to the mandibular tooth surface, the patient is asked to open his mouth wide, and the final position of the mandibular maximum mouth opening is read on the measuring plate 3. The distance between the initial position and the final position is the value of the mouth opening.

[0046] The core idea is to transfer the distance that is difficult to measure inside the mouth to outside the mouth through a device for more intuitive and accurate measurement. One device is used to measure the range of motion of jaw protrusion, retraction, and lateral movement, making the measurement more convenient and accurate, greatly improving the measurement efficiency.

[0047] The above description is only a specific example of the present invention and does not constitute any limitation to the present invention. It is obvious that for professionals in this field, after understanding the content and principles of the present invention, it is possible to make various modifications and changes in form and details without departing from the principles and structures of the present invention. However, these modifications and changes based on the ideas of the present invention are still within the scope of protection of the claims of the present invention.

Claims

1. A mandibular motion range measuring ruler, characterized in that: The invention comprises a main body (1) and a measuring rod (2), wherein a slide groove (4) is provided along the length of the main body (1), the middle part of the measuring rod (2) is connected to the main body (1) via a rotating shaft, the measuring rod (2) and the main body (1) can move along the slide groove (4), and the measuring rod (2) can rotate around the rotating shaft; a first in-port connector (5) is provided at one end of the main body (1), and a measuring plate (3) is provided at the other end; one end of the measuring rod (2) is connected to a second in-port connector (6), and a pointer (8) is provided at the other end, and the moving track of the pointer (8) is located in the plane of the measuring plate (3); and a scale line (9) is provided on a side of the measuring plate (3) facing the pointer (8).

2. The mandibular motion range measuring ruler according to claim 1, characterized in that: The tip of the pointer (8) contacts the side of the measuring plate (3) having the scale lines (9), and the pointer (8) is perpendicular to the measuring plate (3).

3. The mandibular motion range measuring ruler according to claim 1, characterized in that: The scale lines (9) include longitudinal scale lines and transverse scale lines that are perpendicular to each other, and the longitudinal scale lines are parallel to the length direction of the main body (1).

4. The mandibular motion range measuring ruler according to claim 1, characterized in that: The rotating shaft is a suspension knob (7), the main body diameter of the suspension knob (7) is smaller than the slide slot (4), the end cover diameter of the suspension knob (7) is larger than the slide slot (4), and a nut is arranged on the main body of the suspension knob (7).

5. The mandibular motion range measuring ruler according to claim 4, characterized in that: A partition is fixedly arranged in the middle of the suspension knob (7), and nuts are connected at both ends.

6. The mandibular motion range measuring ruler according to claim 1, characterized in that: The first intra-oral connector (5) and the second intra-oral connector (6) have the same structure, comprising a base (11) fixed on the main body (1) or the measuring rod (2), a patch (10) adhered to one side of the tooth surface, and a connecting rod (12) between the base (11) and the patch (10), wherein the connecting rod (12) is a universal joint connection structure.

7. The mandibular motion range measuring ruler according to claim 1, characterized in that: A detachable slot device is provided on the pointer (8), the slot device comprising an adjustable clamp and a slot, and the clamp can be released by rotating or sliding.

8. The mandibular motion range measuring ruler according to claim 1, characterized in that: The pointer (8) is a pen tip.

9. The mandibular motion range measuring ruler according to claim 1, characterized in that: The distance between two adjacent scale lines (9) on the measuring plate (3) is 0.5 mm, 1 mm or 1.5 mm.

10. A method for measuring the range of mandibular motion, characterized in that: Based on the mandibular motion range measuring ruler according to any one of claims 1 to 9, the first intraoral connector (5) is adhered to the mandibular tooth surface, the second intraoral connector (6) is adhered to the mandibular tooth surface, and the person being tested is instructed to move the mandible forward, leftward, rightward, leftward, and rightward; the corresponding motion range value is read out through the measuring plate (3); The measuring ruler is rotated 90 degrees with the long axis as the rotation axis, the first intraoral connector (5) is adhered to the mandibular tooth surface, and the second intraoral connector (6) is adhered to the mandibular tooth surface. At this time, the pointer (8) will point to an initial position on the measuring plate (3). The person to be measured is asked to open his mouth wide, and the final position of the mandibular maximum mouth opening is read on the measuring plate (3). The distance between the initial position and the final position is the value of the mouth opening.

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