Dental unit

Abstract

To provide a dental unit capable of flexibility corresponding to an action of a patient and operating comfortably for the patient.SOLUTION: A dental unit includes: a seat part provided so as to be liftable; a patient chair including a back plate that can rotate with respect to the seat part and be inclined and erected; a sensor provided in the back plate and detecting whether the patient is leaning on the back plate; and an arithmetic device performing arithmetic operation by receiving an output result of the sensor. The arithmetic device performs arithmetic operation as to whether to change a rotation speed of the back plate or arithmetic operation as to whether to make timing of a rotation start of a spittoon earlier on the basis of the output result of the sensor.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a dental unit having a patient chair on which a patient sits in a dental clinic. [Background technology]

[0002] A dental unit is a unit in which various equipment used during dental treatment is provided, and includes a patient chair on which a patient sits. Around the dental unit, there are a doctor unit in which various tools for dental treatment used by the practitioner are arranged, an assistant hanger in which various tools mainly used by assistants are arranged, a water supply unit that supplies mouthwash etc. to the patient, a spitting receptacle for draining the water, a dental light for illuminating the patient's oral cavity, etc. Also, a chair on which the practitioner sits may be placed around the dental unit. The patient chair is constructed so that it can be raised and lowered freely and the backrest can be tilted and raised to allow the patient to assume a position that is easy for treatment or therapy to take.

[0003] The trigger for raising / lowering and tilting / standing up of the patient chair is given by the practitioner, but once the raising / lowering or tilting / standing up has begun, the raising / lowering or tilting / standing up is performed automatically at a predetermined speed or angular velocity.

[0004] Patent Document 1 discloses that a seat sensor detects whether a patient is seated and operates armrests in conjunction with the movement of the seat or backrest. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-99369 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, some patients do not always change their posture when the backboard tilts, but rather stand up on their own or maintain their posture without noticing that the backboard is tilted. Such patient behavior can unexpectedly cause confusion for the patient.

[0007] In view of the above problems, an object of the present disclosure is to provide a dental unit that can flexibly respond to the actions of a patient and operate more comfortably for the patient. [Means for solving the problem]

[0008] The present application discloses a dental unit comprising a patient chair having a seating section which can be raised and lowered, and a backboard which can be rotated relative to the seating section to tilt and stand up, a sensor attached to the backboard which detects whether the patient is leaning against the backboard, and a calculation device which receives output results from the sensor and performs calculations, the calculation device calculating whether to change the rotation speed of the backboard based on the output results from the sensor.

[0009] When tilting the back panel, the calculation device may perform a calculation based on the output result from the sensor to determine whether to reduce the rotation speed for tilting the back panel.

[0010] When the back panel is raised, the calculation device may perform a calculation based on the output result from the sensor to determine whether or not to increase the rotation speed for raising the back panel.

[0011] The present application also discloses a dental unit including a patient chair including a seating portion that is movable up and down and a backboard that is rotatable relative to the seating portion to tilt and stand up, a sensor that is installed on the backboard and detects whether a patient is leaning against the backboard, a movably installed cuspidor for use by the patient, and a computing device that receives an output result of the sensor and performs a computation, wherein the computing device computes whether to advance a timing to start rotating the cuspidor, based on the output result from the sensor. Effect of the Invention

[0012] According to the dental unit of the present disclosure, the patient's behavior is detected by a sensor on the back panel, and control is performed based on the detection results, allowing for flexible response and making the dental unit more comfortable for the patient. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a plan view of the dental unit 1. [Diagram 2] FIG. 2 is a front view of the dental unit 1. [Diagram 3] FIG. 2 is a left side view of the patient chair 10. [Figure 4] FIG. 2 is a diagram illustrating a calculation device 50. [Diagram 5] FIG. 1 is a diagram showing a control flow according to the first embodiment. [Figure 6] FIG. 11 is a diagram showing a control flow according to the second embodiment. [Figure 7] FIG. 11 is a diagram showing a control flow according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present disclosure will be described based on the embodiments shown in the drawings, but the present invention is not limited to these embodiments.

[0015] 1. Dental unit configuration Figures 1 and 2 show the appearance of a dental unit 1 according to one embodiment. Figure 1 is a plan view (viewed from above), and Figure 2 is a front view (viewed from the front direction, as viewed from the direction indicated by arrow II in Figure 1). Figure 3 shows a left side view (viewed from the direction indicated by arrow III in Figure 1) of a patient chair 10 provided in the dental unit 1. The dental unit 1 includes a patient chair 10, a doctor unit 20, an assistant unit 30, a sensor 40, and a computing device 50 (see FIG. 4). However, the dental unit 1 may include other devices as necessary. For example, a dental light may be included. The dental light is attached via an arm that can move and rotate with a high degree of freedom using a universal joint or the like so that the patient's oral cavity can be properly illuminated during treatment. Therefore, by adjusting the position and angle of the dental light, the practitioner can move the dental lighting device to a position where the patient's oral cavity can be properly observed. The dental light may be moved manually or automatically using a gas spring or air cylinder provided in the arm.

[0016] 1.1. Patient chair In this embodiment, the patient chair 10 includes a base 16 , a seat panel 11 , a back panel 12 , a headrest 13 , a legrest 14 , and armrests 15 .

[0017] The base 16 (see FIG. 3) is disposed at the lower part of the patient chair 10 and serves as the base of the patient chair 10. The base 16 has an outer shell formed by a housing, and various control devices are housed inside the housing. Examples of the control devices included here include a hydraulic circuit for raising and lowering the patient chair 10 and tilting and standing up, and a hydraulic control means for controlling the hydraulic circuit. Therefore, as shown in FIG. 1 and FIG. 3, a foot switch 16a is provided on the back side of the patient chair 10 of the base 16. The practitioner can issue a command to the hydraulic control means by operating the foot switch 16a or an operation switch on the operation panel 21c of the doctor unit 20, and can control the hydraulic circuit to give an instruction to raise and lower the patient chair 10 and start or stop tilting and standing up.

[0018] Here, in controlling the elevation of the patient chair 10, a linear potentiometer may be disposed as a sensor to obtain the height position of the seating portion 11 (height position of the back board 12) of the patient chair 10. Also, in controlling the tilting and standing of the back board 12 of the patient chair 10, a rotary potentiometer may be provided as a sensor to obtain the inclination angle of the back board.

[0019] The seat plate 11 is attached above the base 16 so as to be movable up and down. The seat plate 11 is raised and lowered by the hydraulic circuit housed in the base 16 as described above. Specifically, the practitioner operates the foot switch 16a or the operation panel 21c of the doctor unit 20 described later, and the hydraulic control means receiving the operation command appropriately operates the hydraulic cylinders incorporated in the hydraulic circuit, thereby raising and lowering the seat plate 11. The back plate 12, headrest 13, and legrest 14 rise and lower together with the seat plate 11. At this time, the height position of the seat plate 11 is detected by a sensor (seat plate sensor), and the height position is controlled by this. The type of sensor used here is not particularly limited, but may be, for example, a linear potentiometer.

[0020] The back plate 12 is a member that is rotatable around one end of the seat plate 11 as shown by the arrow IIIa in Fig. 3, and supports the torso of the patient from the back side. The back plate 12 can be tilted and raised so that the patient can take a seated position or a supine position. The back plate 12 is tilted and raised by a hydraulic circuit connected from within the base 16. Specifically, the practitioner operates the foot switch 16a or the operation panel 21c of the doctor unit 20, and the hydraulic control means that receives the operation command appropriately operates the hydraulic cylinder incorporated in the hydraulic circuit, causing the back plate 12 to start tilting and raising. At this time, the inclination of the back plate 12 may be controlled by a sensor (back plate sensor) detecting the inclination angle. The type of the sensor used here is not particularly limited, but may be, for example, a rotary potentiometer.

[0021] The headrest 13 is a member disposed at the end of the back panel 12 opposite to the end where the seat panel 11 is disposed, and serves to support the patient's head. The headrest 13 is formed to be movable and rotatable so that the patient's head can be positioned in a position convenient for treatment. Such movement of the headrest 13 is performed by a mechanism including a motor incorporated inside the back panel 12. Specifically, the practitioner operates a switch (not shown) provided on the back side of the back panel 12 or the headrest 13, or an operation panel 21c of the doctor unit 20 (described later), and the headrest 13 moves and rotates when the mechanism receives the operation command and starts to operate.

[0022] The leg rest 14 is a member that is provided rotatably around an end of the seat panel 11 opposite to the side where the back panel 12 is arranged, and supports the legs of a patient. The leg rest 14 is rotatable so that it can assume a vertical or horizontal position in accordance with the tilted and standing position of the back panel 12. Such rotation of the leg rest 14 is performed by a link mechanism that operates in conjunction with the tilting and standing of the back panel 12. Specifically, when the practitioner operates the foot switch 16a or the operation panel 21c of the doctor unit 20 as described above, the back panel 12 tilts and stands up, and the leg rest 14 rotates in conjunction with this.

[0023] As is well known, the armrests 15 are members on which a patient can rest both arms when seated in the patient chair 10. Therefore, the armrests 15 are disposed on both sides of the seat plate 11 in the left and right directions (the left and right directions on the paper as viewed in Figs. 1 and 2).

[0024] 1.2.Doctor Unit The doctor unit 20 is provided with various devices on the side of the patient chair 10 opposite to the assistant unit 30. In this embodiment, the doctor unit 20 has a work table 21, a first arm 22, and a second arm 23.

[0025] The work table 21 is a portion where various tools and switches required by the practitioner are provided. Specifically, the work table 21 has a work surface 21a on its upper surface, and a handpiece group 21b used by the practitioner during treatment and a holder for storing them are provided at the rear end of the patient chair 10. Examples of handpieces included in the handpiece group 21b include an air turbine, a micromotor, a scaler, and a syringe. Almost all of the handpieces are connected to an electric circuit, a water circuit, an air circuit, and the like via tubes. In addition, an operation panel 21c is provided between the work surface 21a and the holder. The operation panel 21c is provided with various operation switches, and can, for example, start and stop tilting and standing of the patient chair 10, start and stop lifting and lowering, and switch on and off the dental lighting.

[0026] The first arm 22 is a so-called arm member having a hollow rod shape, one end of which is disposed under the base 16 and is rotatable within a horizontal plane. The first arm 22 is capable of rotating in the direction indicated by the arrow Ia in FIG. The second arm 23 is also a hollow rod-shaped arm member. One end of the second arm 23 is disposed at the other end of the first arm 22, which is opposite to the base 16 side. In addition, the workbench 21 is disposed at the other end of the second arm 23. The second arm 23 is capable of rotating in the direction indicated by the arrow Ib in FIG. 1.

[0027] 1.3.Assistant unit The assistant unit 30 is installed on a side of the patient chair 10 opposite to the doctor unit 20, and various devices are also provided in the assistant unit 30. In this embodiment, the assistant unit 30 includes a main body 31, an assistant hanger 32, a spitting receptacle 34, and a water supply device 35.

[0028] The main body 31 is a member constituting the main body of the assistant unit 30, and has an outer shell formed by a housing, and various members are accommodated inside the housing. The members accommodated in the main body 31 are not particularly limited, and may include a water supply pipe to the water supply device 35, a drain pipe from the spitting receptacle 34, a mechanism for moving the spitting receptacle 34, a device for cleaning the inside of the pipes, etc.

[0029] The assistant hanger 32 is a portion equipped with tools mainly used by an assistant. Examples of tools arranged on the assistant hanger 32 include a vacuum, a saliva ejector, and a handpiece such as a syringe. In this embodiment, the assistant hanger 32 is connected to the main body 31 by an arm 33 so as to be rotatable.

[0030] The spitting receptacle 34 is used when a patient gargles and cleans the mouth during or after treatment with water supplied from the water supply device 35. The spitting receptacle 34 is bowl-shaped to spit out water in the mouth after gargling. The saliva and water discharged into the spitting receptacle 34 are discharged through a drain trap provided in the main body 31.

[0031] In this embodiment, the spitting receptacle 34 is rotatable within a horizontal plane toward and away from the patient, as indicated by arrow Ic in FIG 1. This allows the spitting receptacle 34 to be located in front of the patient when needed, improving patient convenience. Although the spitting receptacle 34 is configured to rotate in this embodiment, it is not necessarily required and may be configured to move toward and away from the patient. The mechanism for rotating and moving the spitting receptacle 34 is not particularly limited and may be a known mechanism, and the mechanism may be disposed in the main body 31.

[0032] 1.4.Sensors The sensor 40 detects whether the patient is leaning against the backboard 12. For this reason, the sensor 40 is disposed on the backboard 12 as shown in Fig. 2. Information obtained by the sensor 40 is transmitted to the computing device 50, which performs control as described below. The positions and number of sensors 40 are not particularly limited as long as the above-mentioned detection purpose is achieved, and can be set appropriately depending on the shape of the back plate 12. Among them, from the viewpoint of high detection accuracy, it is preferable that the sensors are located near the surface of the back plate 12 facing the patient (not necessarily the outermost surface) and in the center or slightly below the center. However, as will be explained below, depending on the type of sensor 40, it is not necessarily required to place the sensor on the back plate 12.

[0033] The specific type of sensor 40 is not particularly limited, and any known sensor can be used. For example, the following sensors can be mentioned. [Pressure sensor] A pressure-sensitive sensor such as a known piezoelectric element can be used. The pressure-sensitive sensor outputs a voltage according to the pressure (pressure) obtained. The calculation device 50 acquires the voltage as a signal from the sensor. [Body movement sensor] The body motion sensor is a sensor used to detect body motion (body movement), and includes an acceleration sensor or the above-mentioned pressure sensor, and may be, for example, a sensor applied to a medical bed, etc. The body motion sensor can also output the detection result as a voltage, so the calculation device 50 acquires the voltage as a signal from the sensor. [ON / OFF switch] An ON / OFF switch such as a microswitch can also be used. For example, when a patient leans on the backboard 12 with sufficient weight applied, the microswitch is pressed to be in the ON state, and the electrical signal (voltage or current) is sent to the computing device 50. [Potentiometer (1)] As described above, the backboard 12 of the patient chair 10 can be equipped with a rotary potentiometer as a sensor to obtain the inclination angle of the backboard 12. This rotary potentiometer can also be used as a sensor to detect whether the patient is leaning against the backboard. Specifically, when the patient suddenly stands up from a position leaning against the backboard, or conversely, when the patient suddenly puts his / her weight on the backboard, the angle of the backboard changes suddenly in an instant. This sudden change appears as a sudden change in angular velocity, which is detected by the rotary potentiometer and transmitted to the calculation device 50 as a voltage signal. [Potentiometer (2)] In addition to the rotary potentiometers described above, a rotary potentiometer is provided that detects the inclination angle of the backboard when there is no load on the patient, and the voltage signals of the two rotary potentiometers are sent to the arithmetic unit 50. The arithmetic unit 50 receives the two voltage signals and calculates the difference between the two rotary potentiometers to determine whether a load is being applied to the backboard (whether the patient is leaning against the backboard).

[0034] In this embodiment, the sensor 40 is disposed only on the back panel 12, but it may also be disposed on the seat panel 11 accordingly. This makes it possible to know whether the patient is reliably seated.

[0035] 1.5. Arithmetic device The computing device 50 receives a signal from the sensor 40, calculates whether the patient is putting his / her weight (leaning) on ​​the back 12 of the patient chair 10, and sends a control signal to each part of the dental unit 1 or maintains the current state depending on the calculation result. The configuration of the computing device 50 is conceptually shown in Figure 4. As can be seen from FIG. 4, the computing device 50 includes an operator 51, a RAM 52, a storage device 53, a receiving device 54, and an output device 55.

[0036] The operator 51 is composed of a so-called CPU (central processor), and is connected to each of the above-mentioned components, and is a means for controlling them. The operator 51 also executes various programs stored in the storage device 53, which functions as a storage medium, and performs calculations as a means for generating various data and selecting data based on the programs.

[0037] The RAM 52 is a component that functions as a working area for the operator 51 and a temporary data storage means. The RAM 52 can be composed of an SRAM, a DRAM, a flash memory, or the like, and is similar to a known RAM.

[0038] The storage device 53 is a member that functions as a storage medium for storing programs and data that are the basis for various calculations. The storage device 53 may also be capable of storing various intermediate and final results obtained by executing the programs.

[0039] In the present embodiment, one of the programs stored in the storage device 53 includes a calculation for acquiring a signal from the sensor 40, calculating whether the patient is putting his / her weight (leaning) on ​​the back panel 12 of the patient chair 10 based on the signal, and transmitting a command to a control device for driving the tilting and standing of the back panel 12 and a device for controlling the rotation and movement of the spitting receptacle, as necessary. Specific control will be described below.

[0040] 2. Specific aspects of control The following describes specific examples of control modes by the dental unit 1. The flow of each mode is shown in Figs. 2.1. Aspect 1 5 shows the flow of control S10 according to the embodiment 1. In control S10, when the back 12 of the patient chair 10 is transformed from a reclined position to a standing position, the back 12 is designed to assist the patient in standing up as much as possible even when the seated patient tries to stand up by himself / herself. Specifically, the control is performed as shown in steps S11 to S16.

[0041] In step S11, a command is issued to transform the patient chair 10. In this embodiment, the transformation includes the back 12 of the patient chair 10 changing from a reclined position to an upright position as described above. The transformation includes the raising and lowering of the seat 11 and the rotation of the leg rest 14, but the description will be focused on the back 12 here. In step S11, the practitioner operates the foot switch 16a or the operation panel 21c to start raising the backboard 12.

[0042] In step S12, the back panel 12 is raised based on the command given in step S11.

[0043] In step S13, a signal is acquired from the sensor 40. As described above, in this embodiment, the signal from the sensor 40 is acquired by the arithmetic device 50.

[0044] In step S14, a calculation is performed based on the signal obtained in step S13 to determine whether or not a load is being applied to the backboard 12, i.e., whether or not the patient is leaning with his or her body against the backboard 12. This determination is performed by the calculation device 50 that has obtained the signal, using a program stored in the calculation device 50. When it is determined in step S14 that a load is being applied to the backboard 12, it is determined that the patient is resting his / her body on the backboard 12 and is therefore in a normal state, and the process proceeds to step S16. On the other hand, when it is determined in step S14 that no weight is being applied to the backboard 12, it is determined that the patient has sat up by himself and his back has been released from the backboard 12, and the process proceeds to step S15.

[0045] In step S15, since it is determined in step S14 that no weight is being applied to the back board 12, the speed at which the back board 12 stands up is increased. This makes it possible to assist the patient in standing up by himself / herself.

[0046] In step S16, after step S15 or after step S14, it is determined whether the upright position of the back panel 12 is completed. This is performed by the control device 50 determining whether the back panel 12 is in a predetermined upright position. If the standing of the back panel 12 is not completed, the process returns to step S12 and control is continued. On the other hand, if the standing of the back panel 12 is completed, the process ends.

[0047] According to the first aspect, even if the patient stands up or tries to stand up on his / her own during the standing up motion of the backboard 12, the backboard 12 can assist the patient by catching up with the patient as quickly as possible.

[0048] 2.2. Aspect 2 6 shows the flow of control S20 according to embodiment 2. In control S20, when the backboard 12 of the patient chair 10 is transformed from an upright position to a reclined position, even if the seated patient is unable to reclined his / her body in accordance with the backboard 12, the backboard 12 is made to assist the transformation of the patient to a reclined position as much as possible. Specifically, control is performed as shown in steps S21 to S26.

[0049] In step S21, a command is issued to change the shape of the patient chair 10. In this embodiment, the change includes the change of the back 12 of the patient chair 10 from an upright position to a reclining position, as described above. The change includes the raising and lowering of the seat 11 and the rotation of the leg rest 14, but the description will be focused on the back 12 here. In step S21, the practitioner operates the foot switch 16a or the operation panel 21c to start tilting the back panel 12.

[0050] In step S22, the tilting of the back panel 12 proceeds based on the command given in step S21.

[0051] In step S23, a signal is acquired from the sensor 40. As described above, in this embodiment, the signal from the sensor 40 is acquired by the arithmetic device 50.

[0052] In step S24, a calculation is performed based on the signal obtained in step S23 to determine whether or not a load is being applied to the backboard 12, i.e., whether or not the patient is leaning with his or her body against the backboard 12. This determination is performed by the calculation device 50 that has obtained the signal, using a program stored in the calculation device 50. When it is determined in step S24 that a load is being applied to the backboard 12, it is determined that the patient is resting his / her body on the backboard 12, which is a normal state, and the process proceeds to step S26. On the other hand, when it is determined in step S24 that no weight is being applied to the backboard 12, the patient is unable to keep up with the tilt of the backboard 12 and only the backboard 12 is tilting, so it is determined that the patient's back is separated from the backboard 12, and the process proceeds to step S25.

[0053] In step S25, since it is determined in step S24 that no weight is being applied to the backboard 12, the speed at which the backboard 12 is tilted is reduced. This makes it possible to assist the patient in quickly tilting his or her body to match the tilt of the backboard 12.

[0054] In step S26, after step S25 or after step S24, it is determined whether the tilting of the back panel 12 is completed. This is performed by the control device 50 determining whether the back panel 12 is in a predetermined tilted position. If the tilting of the back panel 12 is not complete, the process returns to step S22 and control continues. On the other hand, if the tilting of the back panel 12 is complete, the process ends.

[0055] According to the second aspect, when the patient is unable to keep up with the tilt of the backboard 12 for some reason during the tilting motion of the backboard 12 and his / her back comes off the backboard 12, even if the patient quickly tries to tilt his / her body by himself / herself, the speed of tilting the backboard 12 is slowed down so that the patient can quickly catch up with the backboard 12 and be assisted.

[0056] 2.3. Aspect 3 7 shows a flow of control S30 according to the third embodiment. In control S30, when the back panel 12 of the patient chair 10 is changed from a reclined position to a standing position, the rotation of the spitting receptacle 34 can be prevented from being delayed when the seated patient tries to stand up by himself / herself. This enables the patient to swiftly move on to the next action, such as gargling. Specifically, the control is performed as shown in steps S31 to S35.

[0057] In step S31, a command is issued to transform the patient chair 10. In this embodiment, the transformation includes the back 12 of the patient chair 10 changing from a reclining position to an upright position, as described above. The transformation includes the raising and lowering of the seat 11 and the rotation of the leg rest 14, but the description here focuses on the back 12. In step S31, the practitioner operates the foot switch 16a or the operation panel 21c to start raising the back board 12.

[0058] In step S32, the back panel 12 is raised based on the command given in step S31.

[0059] In step S33, a signal is acquired from the sensor 40. As described above, in this embodiment, the signal from the sensor 40 is acquired by the arithmetic device 50.

[0060] In step S34, a calculation is performed based on the signal obtained in step S33 to determine whether or not a load is being applied to the backboard 12, i.e., whether or not the patient is leaning with his or her body against the backboard 12. This determination is performed by the calculation device 50 that has obtained the signal, using a program stored in the calculation device 50. If it is determined in step S34 that a load is applied to the back panel 12, the patient is resting his / her body on the back panel 12, so that the state is determined to be normal, and the control is terminated. At this time, the spitting receptacle 34 is rotated as described above and positioned in front of the patient at the normal timing. On the other hand, when it is determined in step S34 that no weight is being applied to the backboard 12, it is determined that the patient has sat up by himself and his back has been released from the backboard 12, and the process proceeds to step S35.

[0061] In step S35, since it is determined that no load is applied to the back plate 12 in step S34, the timing to start rotating the spitting receptacle 34 is advanced and the control is terminated. As a result, even if the patient stands up by himself, the patient can smoothly proceed to the next action, such as gargling.

[0062] According to the third aspect, even when the patient stands up by himself / herself during the raising motion of the back panel 12, it is more likely that the spitting receptacle 34 is not ready, and the patient can be assisted in performing the next motion.

[0063] Although the above describes the first to third aspects separately, any two or all three of them may be applied in combination. [Explanation of symbols]

[0064] 1: dental unit, 10: patient chair, 12: backrest, 20: doctor unit, 30: assistant unit, 34: cuspidor, 40: sensor, 50: control device

Claims

1. A patient chair including a seat portion that can be raised and lowered and a back plate that can be rotated with respect to the seat portion to tilt and stand up; A sensor provided on the backboard for detecting whether a patient is leaning against the backboard; A calculation device that receives the output result of the sensor and performs a calculation, The arithmetic device performs a calculation to determine whether to change the rotation speed of the back plate based on the output result from the sensor. Dental unit.

2. 2. The dental unit according to claim 1, wherein the arithmetic device performs a calculation to determine whether to reduce a rotation speed for tilting the back plate, based on an output result from the sensor, when tilting the back plate.

3. 3. The dental unit according to claim 1, wherein the arithmetic device performs a calculation to determine whether to increase a rotation speed for raising the back plate from an output result of the sensor when the back plate is raised.

4. A patient chair including a seat portion that can be raised and lowered and a back plate that can be rotated with respect to the seat portion to tilt and stand up; A sensor provided on the back panel for detecting whether the patient is leaning against the back panel; a movably provided cuspidor for use by a patient; A calculation device that receives the output result of the sensor and performs a calculation, the computing device computes whether to advance a timing to start rotating the spitting receptacle, based on an output result from the sensor. Dental unit.

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