Suction apparatus

Abstract

A dental suction apparatus 1 comprising a robotic arm 2 carrying a suction tube 4 having a first end for insertion into an oral cavity and a second end 5 connected to a vacuum system 10. A positioning

Description

The present invention relates to a suction apparatus for use in dental procedures. Recent trends in medical innovation are aiming to automate many of the procedures and tasks carried out by medical practitioners. Such automation has the potential to reduce costs and increase the number of patients that can be seen, providing better access to medical care. One particular area of interest is the automation of procedures normally carried out by a medial nurse or assistant, including in the field of dentistry. Automation of tasks normally carried out by a dental nurse has the potential to reduce the running costs of a dental surgery, making dental care more accessible. Whilst some tasks and procedures normally carried out by a medical (e.g. dental) nurse or assistant can be readily automated, various constraints have hitherto prevented automation of other tasks. One such task of particular importance in dental procedures is operation of a suction device for the removal of fluid and detritus from the oral cavity of a patient. A typical suction device comprises a tube or hose connected to a vacuum system. An end of the tube is placed into an appropriate position within the oral cavity of the patient and is manoeuvred during the course of the procedure to a desired location in close proximity to the procedure being performed. The process is typically carried out by a trained dental nurse to ensure that the suction is carried out effectively and safely. For the benefits of automated dental tasks to be fully realised, it is necessary for all tasks carried out by a dental nurse to be automated. However, the automation of dental suction procedures has hitherto been unrealised due to the complications that arise from safely performing the procedure. In particular, inaccurate placement of the end of the suction tube may cause the suction tube to engage with parts of the patient’s anatomy such as the gums, inner cheeks, lips, tongue etc., which may cause significant pain or discomfort to the patient. The present invention arose in an attempt to provide a solution to the abovementioned problems. According to a first aspect of the present invention there is provided a dental suction apparatus comprising: a robotic arm carrying a suction tube, the suction tube having a first end for insertion into an oral cavity, in use, and a second end connected to a vacuum system for generating suction within the suction tube, a positioning system arranged to capture data relating to the position of a patient’s oral cavity, in use, and a control unit arranged to: determine a position of a patient’s oral cavity based on data received from the positioning system; define a target position within an oral cavity of a patient; control movement of the robotic arm so as to position the first end of the suction tube into the target position; and control operation of the vacuum system. The present invention allows a suction tube of the suction apparatus to be appropriately positioned in an automated procedure. The robotic arm may be of any suitable construction known to a person skilled in the art of robotics. The positioning system of the apparatus allows the position of a patient’s oral cavity in three-dimensional space to be determined. The control unit is configured to determine a target position for the first end of the suction tube in three-dimensional space, the target position being an appropriate position within the patient’s oral cavity for the procedure being performed. The control unit may be configured to continuously receive data from the positioning system relating to the position of a patient’s oral cavity during the course of a procedure, and to continuously control the movement of the robotic arm and / or control the operation of the vacuum system in response thereto. Preferably, the control unit may be configured to continuously update the target position during a procedure, in response to a detected movement of the patient’s oral cavity. Accordingly, movement of the robotic arm and / or the target position can be updated in real-time in response to movement of the patient during the procedure. This ensures safety of the patient by preventing the suction tube from engaging with the inside of the oral cavity due to unexpected movement of the patient. The control unit may be configured to cease operation of the vacuum system in response to a detected movement of the patient’s oral cavity. For example, the control unit may be arranged to determine when a distance moved by the oral cavity (and / or a reference point within or proximal to the oral cavity) within a predetermined period of time exceeds a threshold value. Such movement may be indicative of a sudden, unexpected movement of the patient. In order to ensure the safety and comfort of the patient in such scenarios, the vacuum system is turned off to prevent damage to the patient in the event that the first end of the suction tube comes into contact with part of the patient’s oral cavity. The robotic arm may comprise at least one force sensor arranged to detect a force applied at or near the first end of the suction tube, wherein the control unit is further configured to: receive a signal from the force sensor indicative of said force applied at or near the first end of the suction tube, and cease operation of the vacuum system in response to the detection of an applied force exceeding a predetermined threshold, or a change in applied force exceeding a predetermined threshold. With this configuration, contact between the first end of the suction tube and any internal parts of the patient’s oral cavity can be detected. The predetermined threshold may be determined so as to be indicative of a dangerous contact, whilst minor contact does not cause operation of the vacuum system to cease. Appropriate thresholds will be dependent on the type of force sensor and can be determined by a person skilled in the art. The force sensor may be any appropriate sensor capable of determining a force applied or experienced at or near the first end of the suction tube. The force sensor may be incorporated into the robotic arm and indirectly determines a force applied or experienced by the suction tube. Non-limiting examples of a suitable force sensor include a strain gauge and a piezoelectric sensor. The control unit may be further configured to move the first end of the suction tube into a second position upon detection of an applied force exceeding a predetermined threshold, or a change in applied force exceeding a predetermined threshold, said second position being predetermined so as to be external to the oral cavity of a patient, in use. When contact is detected, the control unit controls movement of the suction tube out of the patient’s oral cavity, in addition to ceasing operation of the vacuum system. Safety of the patient is thereby further improved. The control unit may be configured to cease operation of the vacuum system and / or move the first end of the suction tube into the second position in response to the detection of an applied force exceeding a predetermined threshold, or a change in applied force exceeding a predetermined threshold, for a predetermined period of time. Operation / use of the apparatus can thus continue in the event of a minor contact taking place for a short period of time (i.e. an amount of time less than the predetermined period of time). Only in the event that the detected contact continues for a longer period of time greater than the predetermined threshold is the vacuum system shut down and / or the suction arm moved. This prevents unnecessary down time of the apparatus and ensures that the dental procedure is not interrupted in the event of a minor (less dangerous) contact event. The positioning system may comprise one or more cameras arranged to produce images of a patient, in use, and wherein the control unit is arranged to: a. receive images of a patient from the or each camera; b. determine from said images a position of at least one part of a patient’s anatomy; and c. define the target position within the oral cavity in dependence on the determined position of at least one part of the patient’s anatomy. In such embodiments, the positioning system is an image recognition system. The use of an image recognition system is a suitable means for recognising the features of a patient’s anatomy and to automatically determine the position of the oral cavity at least in part in dependence thereon. The camera or cameras are preferably facial recognition cameras arranged to be positioned external to a patient’s oral cavity, in use. In such embodiments, the control unit is further configured to determine a position of a patient’s oral cavity from images received from the or each facial recognition camera, and to define the target position at least in part in dependence on the determined position of the patient’s oral cavity. It will be appreciated that the facial recognition cameras of such embodiments may comprise the cameras and appropriate processing software, which software may be incorporated into the control unit. The control unit may be configured to detect movement of the patient’s oral cavity based on images received from the at least one facial recognition camera. The apparatus is thus configured to continuously monitor the position of the patient’s oral cavity by means of the facial recognition cameras, detect movement of the oral cavity, and control operation of the vacuum system and / or movement of the robotic arms in dependence thereon. The apparatus may comprise at least one camera arranged to be positioned inside a patient’s oral cavity, in use, the control unit being configured to determine a position of at least one part of an anatomy of the patient’s oral cavity and to define the target position at least in part in dependence thereon. Non-limiting examples of the part of the anatomy of the patient’s oral cavity include a patient’s lip or lips, teeth, palate, tongue, gums or inner cheek, for example. The target position can thus be defined to be positioned away from parts of the patient’s oral cavity which could cause damage or discomfort to the patient in the event of contact. Additionally, the target position can be defined so as to be an appropriate distance from e.g. the patient’s teeth, such that the apparatus can perform the suction operation most effectively. To achieve this, the camera is preferably positioned at or near the first end of the suction tube, such that the environment in the vicinity of the first end of the suction tube can be reliably determined. The positioning system may comprise a positioning member arranged to be located, in use, on a patient in a predetermined position relative to said patient’s oral cavity, wherein the control unit is configured to define the target position of the first end of the suction tube at least in part in dependence on the position of the positioning member. Such a positioning member can be placed by the dentist on a patient in a predetermined position, for example on an upper lip. The position of the patient’s oral cavity can thus be determined by reference to the position of the positioning member, allowing the target position to be defined appropriately. For example, the target position may be defined as a position relative to the positioning member in three-dimensional space. Since the positioning member is placed at a known position on the patient, the target position can be reliably defined as a position that is inside of the patient’s oral cavity. The positioning member may be used alone or in conjunction with other components of the positioning system, such as image recognition cameras, to reliably determine the position of the patient’s oral cavity and reliably define the target position. The positioning member may be any appropriate component suitable for location on the patient and may be incorporated into other apparatus used during the dental procedure, such as a lip retractor, a tooth wedge or a dental dam, for example. A dental dam, sometimes referred to as a rubber dam, is a flexible sheet of material (e.g. latex or nitrile) arranged to be placed over and / or inside of the patient’s oral cavity to isolate one or more teeth from the rest of the oral cavity. The dental dam is typically secured in place using clamps positioned around one or more teeth and / or a bracket positioned around the patient’s jaw. Any one or more of the dental dam, or any clamps, brackets or other components used to secure the dental dam in place, may be used as the positioning member. For example, a clamp used to secure the dental dam around a particular tooth or teeth will be in a predictable, predefined position within the patient’s oral cavity. The user (e.g. dentist) may feed information into the control unit relating to which tooth or teeth the clamp is attached to. The position of the clamp in three-dimensional space, combined with the information relating to which tooth or teeth the clamp is attached to, can then be used to reliably determine the position of the patient’s oral cavity and a suitable target position therein. The target position may be defined as a position relative to the clamp (or other positing member). Dental dams are typically a distinctive colour (commonly green) to provide clear contrast to the tooth or teeth on which the procedure is being performed. In some embodiments, the dental dam may comprise a flexible sheet of a predetermined first colour, the sheet further comprising a mark of a predetermined second colour, different to the first colour, the mark being provided in a predefined position on the sheet and arranged to be positioned by the dentist in a predefined position with the patient’s oral cavity. The positioning system may comprise a camera arranged to recognise the colour contrast between the first and second colours, such that the control unit is able to determine the position of the mark and determine the position of the patient’s oral cavity at least in part in dependence on the position of the mark in three-dimensional space. The positioning system may comprise a proximity sensor arranged to capture data relating to a position of a dental tool or instrument within an oral cavity of a patient, wherein the control unit is configured to receive said data, determine from said data a position of said dental tool or instrument, and to define the target position of the first end of the suction tube in dependence on the determined position of said dental tool or instrument. A position of the first end of the suction tube relative to the dental tool can thus be determined and controlled. The target position may be continuously updated in dependence on the position of the tool, such that the first end of the suction tube is arranged to ‘follow’ the dental tool during the course of the procedure. The proximity sensor may be arranged to determine the proximity of the dental tool to a point at or near the first end of the suction tube and / or to a point on the robotic arm carrying the suction tube, such as a gripper of the robotic arm. The first end of the suction tube can be controlled to be a predetermined minimum distance and / or a predetermined maximum distance from the dental tool. This ensures that the suction tube can be located in sufficient proximity to the tool to perform the suction operation effectively, whilst at the same time not being too close to the tool. Preferably, the target position is defined as a position that is a minimum predetermined distance from the determined position of the dental tool or instrument. Numerous suitable proximity sensors for determining the proximity between the suction tube and the dental tool will be known to the skilled person. Non-limiting examples include magnetic sensors, eddy current sensors, Hall effect sensors, inductive sensors, capacitive sensors, optical sensors and ultrasonic sensors. The proximity sensor may comprise cooperating components provided in or on the dental tool and the suction tube, respectively. For example, the proximity sensor may comprise a sensor in one of the tool or the suction tube, and a cooperating tag in the other of the tool or the suction tube. Other appropriate sensor arrangements will be known to the skilled person. For example, a camera located within the patient’s oral cavity may be used, wherein the control unit is arranged to determine the position of the dental tool based on data received from said camera. The camera may be the same or a different camera to the camera used to determine a position of a part of the anatomy of the patient’s oral cavity (where such a camera is provided), as discussed above. The apparatus may further comprise a thermal sensor, such as a thermal imaging camera, wherein the control unit is arranged to receive data from the thermal sensor, detect from said data a position of fluid within the oral cavity of the patient, and to define the target position of the first end of the suction tube at least in part in dependence on the detected position of fluid within the oral cavity of the patient. This arrangement is particularly advantageous in detail procedures, wherein tools such as drills commonly produce a fine spray of water. The thermal sensor can detect such sprays based on the thermal properties of the spray, and the control unit can determine a target position that is suitable for collecting the spray and any other fluids / detritus generated during the procedure. Where the thermal sensor comprises a thermal imaging camera, it will be appreciated that the thermal imaging camera may comprise the camera and appropriate processing software, which software may be incorporated into the control unit. The apparatus preferably comprises an override switch arranged to cease operation of the vacuum system upon activation thereof. The override switch may alternatively or additionally cause movement of the first end of a suction tube to a position that is arranged to be external to a patient’s oral cavity. The dentist can thereby maintain overall control over the suction operation and can ensure that the dental procedure is performed safely. The robotic arm may comprise a gripper arranged to hold the suction tube. Accordingly, the apparatus can incorporate a conventional dental suction device. Alternatively, the robotic arm may have the suction tube incorporated integrally therein. According to a second aspect of the present invention, there is provided a method of performing a dental suction operation, the method comprising: providing a dental suction device in accordance with the first aspect; operating the control unit to automatically define a target position with a patient’s oral cavity, and to control the robotic arm so as to position the first end of the suction tube in the target position; and activating the vacuum system so as to generate suction within the suction tube. Non-limiting embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a schematic drawing of a dental suction apparatus in accordance with the present invention; and Figures 2A and 2B are flow charts illustrating a method of performing a dental suction apparatus in accordance with the present invention. In Figure 1 there is shown a schematic representation of a dental suction apparatus 1 in accordance with the present invention. The apparatus 1 comprises a robotic arm 2 arranged to carry a suction tube 4 suitable for performing a suction operation during a dental procedure. The suction tube 4 has a first end for insertion into an oral cavity of a patient in use, and a second end connected to a vacuum system 10 for generating suction within the suction tube 4. It will be appreciated that the suction tube 4 may take any appropriate form and may be integrated into the robotic arm 2 or alternatively separate to the robotic arm 2 and carried by a component of the robotic arm 2, such as a griper. The apparatus 1 further comprises a positioning system 6 that is arranged to capture data relating to the position of a patient’s oral cavity, in use, as will be described in greater detail below. The apparatus 1 also comprises a control unit 8 that is arranged to determine a position of a patient’s oral cavity based on data received from the positioning system 6, define a target position within a oral cavity of a patient, control movement of the robotic arm 2 so as to position the first end of the suction tube 4 into the defined target position, and control operation of the vacuum system 10 to turn on or off suction within the suction tube 4. The control unit 8 comprises a processor 12 arranged to receive data from the positioning system 6, and to process said data to determine a position of a patient’s oral cavity based on said data received from the positioning system 6. The control unit 8 further has a control circuit 14 arranged to control operation of at least the robotic arm 2 and vacuum system 10. In particular, the processor 12, having determined the position of the patient’s oral cavity in three-dimensional space, defines a target position within the oral cavity of patient, the target position being a desired position of the first end of the suction tube 4 in three dimensional space that is located within the oral cavity of the patient. The target position is defined in dependence on the determined position of the patient’s oral cavity, and also on the particular dental procedure being performed and the location within the patient's oral cavity at which said procedure is being performed. For example, data may be input into the processor 12 indicating a particular tooth on which a dental procedure is being performed, and the target position is defined as a suitable position in the vicinity of said tooth that will allow the suction operation to be performed effectively, whilst also allowing the necessary space for the procedure to be performed. Once the target position has been defined by the processor 12, the control circuit 14 controls movement of the robotic arm 2 so as to position the first end of the suction tube 4 in the target position. Once in the target position, the control circuit 14 further controls operation of the vacuum system 10 so as to generate suction within the suction tube 4. The control circuit 14 is further configured to receive data from the processor 12 during the course of the dental procedure and to control the vacuum system 10 and the robotic arm 2 as described below. The apparatus 1 comprises a plurality of inputs configured to capture data relating to the procedure and / or the environment in which the procedure is being performed, the data being fed to the processor 12 to enable the control circuit to operate the vacuum system and robotic arm in a safe and effective manner. In the illustrated embodiment, the plurality of inputs comprises an external camera (facial recognition camera) 16, an internal camera (object recognition camera) 18, a positioning member 20, a proximity sensor 22, a force sensor 24 and a thermal sensor 26. It will be appreciated that alternative embodiments of the present invention may comprise any one or more of said sensors in various combinations. Additional inputs may also be provided to capture data relating to the dental procedure and / or the environment in which the dental procedure is being performed. The positioning system 6 comprises the external camera 16, the internal camera 18 and the positioning member 20. These inputs are used in combination to determine a position of a patient’s oral cavity in three-dimensional space, so as to allow the suction tube 4 to be moved to a target position within the oral cavity of the patient in an automated manner. The external camera 16 is a facial recognition camera configured to recognise a face of a patient and, in particular, the location of the patient’s oral cavity. Suitable cameras and operating software for performing such facial recognition functions will be known to the skilled person. In order to improve the accuracy and reliability of the determination of the position of the patient’s oral cavity, the positioning member 20 is also used in conjunction with the external camera 16. The positioning member 20 is any suitable component which can be located on a patient in a reference position that is fixed relative to the patient’s oral cavity. Accordingly, a position of the positioning member 20 is indicative of the location of the user’s oral cavity. The position of the positioning member 20 is then fed to the processor 12 to assist the determination of the position of the patient’s oral cavity. In particularly advantageous embodiments, the positioning member 20 may be incorporated into another piece of equipment used during the dental procedure, such as a lip retractor or a tooth wedge. Such equipment, when placed into the patient's oral cavity, will maintain a fixed position relative to the patient's oral cavity, and, therefore, a position of such equipment in three-dimensional space is indicative of the position of patient’s oral cavity. Accordingly, the position of the positioning member 20 provides data indicative of the position of the patient’s oral cavity, allowing a suitable target position within the patient’s oral cavity to be defined. It will be appreciated that the positioning member 20 comprises means for determining and / or communicating its position in three-dimensional space to the processor, which means may be any appropriate sensor arrangement for determining a position of the positioning member 20 in three-dimensional space. The positioning system 6 further comprises an internal camera 18 arranged to be located inside the patient’s oral cavity in use. The internal camera is thus configured to determine the internal environment of the patient’s oral cavity and in particular to determine a position of at least one internal part of the anatomy of the patient’s oral cavity. The information relating to the internal environment of the oral cavity can thus be used to define a more specific target position. For example, in one envisaged embodiment, an initial target position may be determined in dependence on data received from the external camera 16 and the positioning member 20. The control circuit 14 then controls movement of the robotic arm 2 so as to position the first end of the suction tube 4 into the first target position. The internal camera 18 may likewise be carried by the robotic arm 2 such that it is positioned within the patient’s oral cavity, allowing imaging of the internal environment. The processor 12 may then be arranged to determine a position of the patient’s tongue, for example, and define a second target position within the oral cavity that is located away from the tongue. The control circuit 14 can then further control movement of the robotic arm 2 to reposition the first end of the suction tube 4 into the second target position. It will be appreciated that, in this manner, the control unit 8 is configured to continuously receive data from the positioning system 6 during the course of a dental procedure, and to continuously control movement of the robotic arm 2 in response. The additional inputs may be used to collect information relating to the procedure, to allow the control unit 8 to control movement of the robotic arm 2 and / or operation of the vacuum system 10 in a safe and effective manner. The force sensor 22 is arranged to detect a force applied at or near the first end of the suction tube 4: said force may be indicative of the suction tube 4 coming into contact with a part of the patient’s oral cavity. It will be appreciated that such contact may cause damage and / or discomfort to the patient and must therefore be avoided. Accordingly, if a force detected by the force sensor 22 exceeds a predetermined threshold, or a change in applied force exceeds a predetermined threshold, the control unit 8 determines that the first end of the suction tube 4 has come into contact with a part of the user’s oral cavity and therefore turns off the vacuum system 10 to prevent damage or discomfort. The control circuit 14 may also control movement of the robotic arm 2 to move the first end of the suction tube 4 to a position that is located external to the patient’s oral cavity, so that the suction tube 4 is fully removed and cannot cause damage or discomfort. The proximity sensor 24 is provided to determine the proximity of objects internal to the oral cavity in relation to the first end of the suction tube 4. In particular, the proximity of the first end of the suction tube 4 to a dental tool being used for the dental procedure can be determined. The target position can thus be defined to be a suitable distance that is both sufficiently close to said dental tool to effectively perform the suction operation, whilst also providing sufficient space in the vicinity of the dental tool for the procedure to be carried out. The thermal sensor 26 may be a thermal imaging camera, for example. The thermal sensor 26 is used to determine a position of fluid within the oral cavity of the patient that is generated during the dental procedure. The presence of fluid within the oral cavity will normally be detectable by a temperature differential, in particular a region of relatively low temperature compared to other regions of the oral cavity. For example, water spray generated by a dental drill to assist the dental procedure will exhibit a relatively low temperature, and thus a location of low temperature within the patient's oral cavity may be indicative of a desired position of a first end of the suction tube 4 for suctioning said fluid. In this manner, data from the thermal sensor 26 can be used to in part define the target position of the first end of the suction tube 4 within the patient’s oral cavity. The apparatus 1 further comprises an override switch 28 that is operable by the dentist. Activation of the override switch 28 causes the control circuit 14 to turn off the vacuum system 10 and / or control movement of the robotic arm 2 to remove the suction tube from the patient’s oral cavity. In this manner, the dentist performing the dental procedure can maintain overall control over the operation of the apparatus 1 to ensure safety and comfort of the patient. Figures 2A and 2B are flow charts illustrating an exemplary method according to the present invention. It will be appreciated that the illustrated method is exemplary only and various steps may be carried out in alternative sequences. With reference to Figure 2A, at step 100, the apparatus is energised to active all components. In step 102 the positioning system 6 is activated. Any components of the positioning system 6, such as the external camera 16, internal camera 18, positioning member 20 and proximity sensor 24 are activated to capture data relating to the position of a patient’s oral cavity. In step 104, the processor 12 receives data from said inputs of the positioning system to determine a position of the patient’s oral cavity, before defining a target position within the oral cavity for the first end of the suction tube 4 to be positioned. In step 108, the control circuit 14 controls movement of the robotic arm 2 so as to move the first end of the suction tube 4 to the target position. In step 110, the internal environment of the patient’s oral cavity is imaged using the internal camera 18, and in step 112 the processor 12 determines whether the initial target position is appropriate. For example, if the initial target position is determined to be too close to a part of the anatomy of the patient’s oral cavity (such as a tongue or gum) the target position may need to be redefined. If the condition at step 112 is NO, the processor defines a new target position at step 114 and the method loops back to step 108 to move the suction tube to the redefined target position. Once the target position is determined at step 112 to be appropriate (i.e. the condition at step 112 is YES) the method proceeds to step 116, in which the control unit actives the vacuum system 10 to create suction within the suction tube 4. The dental procedure can then be commenced at step 118. The method then proceeds to a monitoring phase in step 120, in which data captured by the various inputs is used to continuously control movement of the robotic arm 2 and operation of the vacuum system 10. An exemplary embodiment of the monitoring phase step 120 is described below with reference to Figure 2B. At step 122, the procedure is completed by the dentist, which may be indicated by user input At step 124, the apparatus 1 is deenergised and the method ends at step 126. Referring now to Figure 2B, the monitoring phase step 120 is described in further detail. Generally, the purpose of the monitoring step is to ensure that the first end of the suction tube 4 is maintained in an appropriate target position and that the procedure is completed in a safe and effective manner. In the illustrated embodiment, the monitoring phase comprises a proximity monitoring step 128, a thermal monitoring step 130, a force monitoring step 132 and a motion monitoring step 134. It will be appreciated that steps 128, 130, 132 and 134 may be carried out simultaneously and operation of the apparatus 1 controlled in dependence on data input from any or all of the inputs. In step 128 a proximity monitoring operation is performed. The proximity monitoring operation 128 comprises step 120A in which the proximity sensor 22 is used to determine a proximity of the first end of the suction tube 4 to an object within the patient’s oral cavity, such as a dental tool. At step 120B it is determined whether the first end of the suction tube 4 is a minimum predetermined distance from said object. If the condition is YES, the method returns to step 128A to continue to measure the proximity of the first end of the suction tube 4 to a dental tool. If the condition at step 120B is NO, the method proceeds to step 120C in which the processor 12 adjusts the target position to a new target position arranged to locate the first end of the suction tube 4 at an appropriate distance from the object. The method then returns to step 120B and continues as described above. In step 130, the thermal sensor 26 senses any temperature differential within the patient’s oral cavity that may be indicative of the presence of fluid. At step 130B, the processor determines whether fluid is present within the patient’s oral cavity and if so, a location of said fluid. If the condition at step 130B is NO, the method returns to step 130A. If the condition at step 130B is yes, the method proceeds to step 130C in which it is determined whether the existing target position is at a predefined proximity to the detected location of fluid. If the condition at step 130C is YES, it is determined that the existing target position is suitable and the method returns to step 130A. If the condition at step 130C is no, the method proceeds to step 130D, in which the processor 12 adjusts the target position to a suitable position relative to the detected fluid within the patient’s oral cavity. The method then returns to step 130C. In step 132, a force monitoring operation takes place. At step 132A, a force experienced by the force sensor 24 is measured. At step 132B, it is determined whether the measured force exceeds a predetermined threshold. If the condition at step 132B is NO, the method returns to step 132A. If the condition at step 132B is YES, the method proceeds to step 132C, in which the vacuum system 10 is deactivated so as to ensure safety of the patient. The method may also proceed to step 132D, in which the control circuit 14 controls movement of the robotic arm 2, to position the first end of the suction tube 4 externally from the patient’s oral cavity, to further ensure the safety of the patient. In step 134, a motion monitoring operation takes place. At step 134A, the processor 12 receives data from the positioning system to monitor the position of the patient’s oral cavity. At step 134B it is determined whether any such motion of the oral cavity has been detected. If the condition at step 134B is NO, the method returns to step 134A. If the condition at step 134B is YES, the method proceeds to step 134C, in which it is determined whether the detected motion exceeds a predetermined threshold. For example, the predetermined threshold may be a maximum predetermined distance moved, or a maximum predetermined distance moved in a predetermined period of time (indicative of a speed of movement). Movement exceeding the threshold may therefore be indicative of an ‘unsafe’ or ‘sudden’ movement of the patient’s oral cavity, which could result in the first end of the suction tube 4 coming into contact with the patient’s oral cavity. If the condition at step 134C is NO, it is determined that the detected motion is within acceptable limits, and the method proceeds to step 134D to adjust the target position in accordance with the detected motion, so that the first end of the suction tube 4 remains in the appropriate position within the patient’s oral cavity. If the condition at step 134C is YES, the method proceeds to step 134E, in which the control circuit deactivates the vacuum system 10 to ensure safety and comfort of the patient. The method may also proceed to step 134F, in which the control circuit 14 controls movement of the robotic arm 2, to position the first end of the suction tube 4 externally from the patient’s oral cavity, to further ensure the safety of the patient. The invention has been described above with reference to specific embodiments, given by way of example only. It will be appreciated that different arrangements of the system are possible, which fall within the scope of the appended claims.

Claims

1. A dental suction apparatus comprising:a robotic arm carrying a suction tube, the suction tube having a first end for insertion into an oral cavity, in use, and a second end connected to a vacuum system for generating suction within the suction tube,a positioning system arranged to capture data relating to the position of a patient’s oral cavity, in use, anda control unit arranged to:determine a position of a patient’s oral cavity based on data received from the positioning system;define a target position within an oral cavity of a patient;control movement of the robotic arm so as to position the first end of the suction tube in the target position; andcontrol operation of the vacuum system.

2. A dental suction apparatus as claimed in claim 0, wherein the control unit is configured to continuously receive data from the positioning system relating to the position of a patient’s oral cavity during the course of a procedure, and to continuously control the movement of the robotic arm and / or control the operation of the vacuum system in response thereto.

3. A dental suction device according to claim 2, wherein the control unit is configured to continuously update the target position during a procedure, in response to a detected movement of the patient’s oral cavity.

4. A dental suction device according to claim 2 or 3, wherein the control unit is configured to cease operation of the vacuum system in response to a detected movement of the patient’s oral cavity.

5. A dental suction apparatus as claimed in any preceding claim, wherein the robotic arm comprises a force sensor arranged to detect a force applied at or near the first end of the suction tube, and wherein the control unit is further configured to:receive a signal from the force sensor indicative of said force applied at or near the first end of the suction tube, andcease operation of the vacuum system in response to the detection of an applied force exceeding a predetermined threshold, or a change in applied force exceeding a predetermined threshold.

6. A dental suction apparatus as claimed in claim 5, wherein the control unit is further configured to move the first end of the suction tube into a second position upon detection of an applied force exceeding a predetermined threshold, or a change in applied force exceeding a predetermined threshold, said second position being predetermined so as to be external to the oral cavity of a patient, in use.

7. A dental suction apparatus as claimed in claim 5 or 6, wherein the control unit is configured to cease operation of the vacuum system in response to the detection of an applied force exceeding a predetermined threshold, or a change in applied force exceeding a predetermined threshold, for a predetermined period of time.

8. A dental suction apparatus as claimed in any preceding claim, wherein the positioning system comprises one or more cameras arranged to produce images of a patient, in use, and wherein the control unit is arranged to:a. receive images of a patient from the or each camera;b. determine from said images a position of at least one part of a patient’s anatomy;andc. define the target position within the oral cavity in dependence on the determined position of at least one part of the patient’s anatomy.

9. A dental suction apparatus as claimed in claim 8, wherein the positioning system comprises at least one facial recognition camera arranged to be positioned external to a patient’s oral cavity, in use, wherein the control unit is further configured to determine a position of a patient’s oral cavity from images received from the or each facial recognition camera, and to define the target position at least in part in dependence on the determined position of the patient’s oral cavity.

10. A dental suction apparatus as claimed in claim 9, when dependent on any one of claims 2 to 3, wherein the control unit is configured to detect movement of the patient’s oral cavity based on images received from the at least one facial recognition camera.

11. A dental suction apparatus as claimed in any preceding claim, comprising at least one camera arranged to be positioned inside a patient’s oral cavity, in use, wherein the control unit is configured to determine a position of at least one internal part of an anatomy of the patient’s oral cavity, and to define the target position at least in part in dependence thereon.

12. A dental suction apparatus as claimed in claim 11, wherein said at least one camera arranged to be positioned inside a patient’s oral cavity is positioned at or near the first end of the suction tube.

13. A dental suction apparatus as claimed in any preceding claim, wherein the positioning system comprises a positioning member arranged to be located, in use, on a patient in a predetermined position relative to said patient’s oral cavity, wherein the control unit is configured to define the target position of the first end of the suction tube at least in part in dependence on the position of the positioning member.

14. A dental suction apparatus as claimed in claim 13, wherein the positioning member is incorporated into a lip retractor, tooth wedge or dental dam.

15. A dental suction apparatus as claimed in any preceding claim, wherein the positioning system comprises a proximity sensor arranged to capture data relating to a position of a dental tool or instrument within an oral cavity of a patient, wherein the control unit is configured to receive said data, determine from said data a position of said dental tool or instrument, and to define the target position of the first end of the suction tube in dependence on the determined position of said dental tool or instrument.

16. A dental suction apparatus as claimed in claim 15, wherein the target position is defined as a position that is a minimum predetermined distance from the determined position of the dental tool or instrument.

17. A dental suction device as claimed in any preceding claim, further comprising a thermal sensor, wherein the control unit is arranged to receive data from the thermal sensor, detect from said data a position of fluid within the oral cavity of the patient, and to define the target position of the first end of the suction tube at least in part in dependence on the detected position of fluid within the oral cavity of the patient.

18. A dental suction device as claimed in claim 17, wherein the thermal sensor is a thermal imaging camera.

19. A dental suction device as claimed in any preceding claim, further comprising an 5 override switch arranged to cease operation of the vacuum system upon activation thereof.

20. A dental suction device as claimed in any preceding claim, wherein the robotic arm comprises a gripper arranged to hold the suction tube.10 21. A method of performing a dental suction operation, the method comprising:providing a dental suction device in accordance with any preceding claim;operating the control unit to automatically define a target position with a patient’s oral cavity, and to control the robotic arm so as to position the first end of the suction tube 15 in the target position; andactivating the vacuum system so as to generate suction within the suction tube.21

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