System for analysis of intraoral soft tissues

Abstract

A system for monitoring intra-oral soft tissue properties is provided. An oral monitoring head includes at least one sensing element, such as a probe that can be placed between cleaning bristles. A tapping motion is applied to the at least one sensing element, and a force, strain, or motion associated with the at least one sensing element is monitored to generate a force, strain, or motion signal. From this signal, viscoelastic material properties of a material in contact with the at least one sensing element are derived. In one example, an indication of gum health can be provided.

Description

[Technical field]

[0001] The present invention relates to the analysis of intraoral soft tissue properties. [Background technology]

[0002] Analysis of intraoral soft tissues such as gums, cheeks, and tongue is an important part of a dental examination. For example, identifying gum recession and gum inflammation is one of the components of a dental examination. Gum recession and inflammation develop slowly and, if left untreated, can lead to serious conditions such as periodontitis. Periodontitis is a chronic gum disease that is reported to affect approximately half of the adult population in the United States, yet more than half of those affected are not diagnosed by a dentist. The main reasons are that the screening process is time-consuming, painful, and can only be performed by a dentist.

[0003] It is therefore desirable to provide a system that is able to analyze the properties of soft tissues, for example to detect gum recession or gum inflammation as efficiently as possible, while minimizing the discomfort of the patient, especially during lengthy examinations.

[0004] The condition of the gums can be evaluated, for example, using impact and shaker tests, which are widely used in structural dynamic analysis to determine the impulse response, mode shapes, resonances, and damping of a test structure by analysis of the time and primarily frequency response.

[0005] In an impact test, the impact generates a short duration, half-sine shaped force pulse. From the classical Hertz theory, the contact force is given by f=K1.q α where K1 is the contact stiffness, q is the relative displacement between the contacting bodies, and α is a nonlinear coefficient. The magnitude and duration of the force pulse depends on the nonlinear contact stiffness. For a given impact magnitude (i.e. momentum, velocity, and inertia of the impacting member), a soft contact surface produces a long pulse with a small force amplitude, whereas a stiff surface produces a short pulse with a large amplitude.

[0006] The paper by M. Kobusch, L. Klaus and L. Muniz Mendoza: Investigation of impact hammer calibrations (IMEKO 23rd TC3, 13th TC5 and 4th TC22 International Conference, May 30-June 1, 2017, Helsinki, Finland) shows the impact signals measured with tips of different material stiffness. The time domain signal (sensor signal vs. time) is shown, from which the different pulse height and pulse width characteristics of the time domain signal can be observed. The frequency domain response can also be analyzed (sensitivity vs. frequency).

[0007] In the frequency domain, long pulses correspond to low frequency components and short pulses correspond to high frequency components.

[0008] It has been shown that as the pulse width increases, the pulse height decreases with decreasing stiffness of the surface material. For example, the pulse shape characteristics can distinguish between rubber samples of different stiffness, and between stiff (steel) and soft (rubber) materials.

[0009] It is also well known that soft biological tissues exhibit frequency-dependent mechanical properties similar to soft elastomers such as silicone rubber.

[0010] As an alternative to impact excitation, dynamic mechanical analysis (DMA) can be performed with a frequency (or temperature) sweep (e.g., in the range of 10-1000 Hz) to derive viscoelastic properties such as storage, loss and loss factors (or damping coefficients), which can be used to characterize the material. In DMA, a sinusoidal tapping motion ("stress") is applied and the sinusoidal response ("strain") of sensing setae, which are preferably held in stationary contact with the target area during excitation, is recorded.

[0011] Figure 1 shows the stress-strain response of a sample subjected to a sinusoidal tapping load, where plot 20 is strain versus time and plot 22 is stress versus time.

[0012] It is known to incorporate sensing capabilities into oral care devices such as toothbrushes and flossing systems. For example, it is known to use pressure sensing related to the delivered fluid flow to detect the transition from hard plaque to softer tissue. Pressure changes arise from differences in flow resistance due to differences in the properties of different surfaces.

[0013] Such pressure sensing can, for example, distinguish between teeth and gums, as well as between teeth and gaps. This information can be used to control a mouthwash or flossing system, for example, to use mouthwash liquid more efficiently.

[0014] Oral treatment devices, such as toothbrushes and flossing heads, are known that incorporate a fluid delivery tube that pumps a liquid (e.g., air) to an output nozzle. For example, a tooth gap can be detected based on a pressure sensor detecting a pressure drop or an increase in flow rate in the fluid delivery tube. The flow of fluid from the fluid delivery tube is more impeded when the nozzle is in contact with a tooth compared to when the opening is away from contact. This allows for the detection of more soft tissue or a lack of tissue, such as a tooth gap. Summary of the Invention [Problem to be solved by the invention]

[0015] However, detection of gum recession and inflammation remains challenging and has not been achieved with integrated sensing approaches such as those mentioned above. It would be interesting to have a quantitative approach to assess changes in gum tissue properties to identify early onset of gum disease, allowing risk stratification / triage associated with gum disease. It would also be beneficial if measurements could be performed during the user's daily oral care / hygiene routine, such as brushing teeth.

[0016] US Patent No. 9,333,060 discloses a fluid jet dental cleaning device in which the jet is controlled based on sensing the condition of the tissue it faces, for example to clean the teeth with high pressure and reduce pressure on the gums. In one example, gum softness can be detected in order to reduce the jet pressure.

[0017] International Patent Publication WO2020 / 212248 discloses a fluid-ejecting oral care device intended to identify the position of a fluid-ejecting head relative to interdental spaces.

[0018] Chinese Patent Publication CN112107386 discloses a system for collecting oral hygiene data. The oral hygiene data can be collected using various sensors, such as gyroscopes, acceleration sensors, pressure sensors, image sensors, ultrasonic sensors, spectrum test sensors, pH sensors, and temperature sensors. [Means for solving the problem]

[0019] The invention is defined by the claims.

[0020] According to an embodiment of this aspect of the present invention, there is provided a system for monitoring intra-oral soft tissue properties, the system comprising: an oral cavity monitoring head including at least one sensing element; an actuator for imparting motion to the at least one sensing element; a force or strain sensor or a motion sensor for monitoring force, strain, or motion associated with the at least one sensing element and generating a force, strain, or motion signal; and a controller, the controller comprising: Controlling the actuator receiving a force, strain, or motion signal; The force, strain or motion signals are analyzed to derive viscoelastic material properties of the material in contact with the at least one sensing element.

[0021] The present invention therefore provides a system for monitoring the properties of intraoral soft tissue, in particular the gums, by probing the soft tissue with a sensing element and analyzing the force or strain to derive material properties. The sensing element is a tip of a probe for contacting the surface of the soft tissue. A force or strain sensor is coupled to the probe.

[0022] The system is for monitoring gum health, and the controller provides an indication of gum health based on the viscoelastic material properties. For example, the indication of gum health may simply be an indication of health or an indication of inflammation, but in more advanced embodiments, a degree of severity may be provided. The system may also provide an indication or even a measure of gum recession in some advanced embodiments.

[0023] For example, at least one sensing element may include a fiber and the force at the tip may be measured or the strain resulting from bending of the fiber may be determined.

[0024] The applied motion may be toward or away from the soft tissue surface (thereby providing tapping on the soft tissue surface with a motion perpendicular to the soft tissue surface), or it may be a frequency signal applied to the proximal end of the sensing element while the distal end remains in contact with the soft tissue surface.

[0025] The controller can also receive intraoral images.

[0026] In the vicinity of at least one sensing element, for example, the color of the soft tissue (e.g., gums) can be determined. Thus, when analyzing gums, the viscoelastic material properties and the color of the gums can be combined to derive an indication of the health of the gums.

[0027] The system may further include an imaging camera (such as one built into the oral monitoring head) for taking intraoral images, although the imaging camera may be a separate device, such as a mobile phone of a user of the system.

[0028] The system may include a head movement or position sensor to detect the location of the oral cavity monitoring head.

[0029] This can be used to identify locations in the soft tissue where viscoelastic material properties are relevant. Image analysis can be used to identify locations within the mouth.

[0030] Image analysis can be combined with other location sensing solutions and the location can be used to map the location of the oral monitoring head to a location within the captured image. For example, by combining image information with location information, the system can determine when the oral monitoring head is on the gums, other intraoral soft tissue, or teeth, or when it has actually moved beyond the tooth / gum border.

[0031] For example, a head movement or position sensor may include an inertial measurement unit that includes an accelerometer and a gyroscope. A six-axis measurement unit may be used to track position and movement in 3D space.

[0032] The controller can analyze the force or strain signals in the time and frequency domains, allowing the material properties to be determined in terms of their time characteristics (i.e. damping effects) and frequency characteristics (i.e. resonance effects).

[0033] For example, the controller can determine a minimum gum stiffness during a monitoring period, which corresponds to a state of maximum inflammation.

[0034] The controller can determine whether the at least one sensing element is in contact with a tooth surface or a gum surface, and determine an indication of gum health only if it is in contact with the gum surface. Thus, false indications can be avoided by detecting when the at least one sensing element is at the gum surface. This can be derived from signal analysis and / or image analysis.

[0035] For any possible type of intraoral soft tissue, for example, the controller controls the actuator to apply a frequency sweep to the motion imparted to at least one sensing element. Thus, the material response to different excitation frequencies is analyzed as part of the determination of the viscoelastic material properties. In this case, the portion of the sensing element in contact with the soft tissue is static and motion is applied to the opposite end.

[0036] The system can therefore use Dynamic Mechanical Analysis (DMA). In such DMA, a sinusoidal force (stress σ) is applied to the soft tissue and the resulting displacement (strain) is measured. For a perfectly elastic solid, the resulting strain will be perfectly in phase with the stress. For a purely viscous fluid, there is a 90 degree phase lag between the strain and the stress. Viscoelastic properties result in a phase lag during DMA testing.

[0037] For example, force, strain, and motion sensors can be Piezoelectric sensors, Strain gauges, Fiber Bragg Grating, accelerometer, Fabry-Perot sensor.

[0038] In a first set of examples, the system may be a stand-alone system for monitoring soft tissue properties, such that the sole purpose of the system is the analysis of soft tissue.

[0039] In other embodiments, soft tissue analysis (eg, gum health analysis) is combined with an oral care device that has another primary function.

[0040] For example, in a second set of embodiments, the present invention provides an electric toothbrush device for performing an oral care routine of tooth brushing. The electric toothbrush device comprises: A handle portion, a brushing head including a bristle arrangement; The above system, wherein the at least one sensing element is part of the brushing head, and the at least one sensing element is within or adjacent to the bristle arrangement.

[0041] Thus, gum health analysis can be performed as part of a tooth brushing routine.

[0042] In a third set of embodiments, the present invention provides a motorized brushing mouthpiece device for performing a mouthpiece teeth cleaning oral care routine, the motorized brushing mouthpiece device comprising: Mouthpiece arch and a brushing arrangement including a bristle arrangement within the mouthpiece arch; The above system, wherein the at least one sensing element is part of the mouthpiece arch, and the at least one sensing element is within or adjacent to the bristle arrangement.

[0043] For example, a brushing mouthpiece device may have a handle that remains outside the mouth and a mouthpiece arch that fits inside the mouth.

[0044] Thus, analysis of gum health may be performed as part of a teeth cleaning routine using a brushing mouthpiece, for example, the at least one sensing element includes a set of sensing elements distributed around a periphery of the mouthpiece arch.

[0045] In a fourth set of embodiments, the present invention provides an oral irrigator device for performing an oral care routine of oral cleaning or flossing, the oral irrigator device comprising: A handle portion, An oral irrigator or flossing head; a squirt tube between the handle and the mouth irrigator or floss head; The above system, wherein at least one sensing element is part of the oral irrigator or flossing head.

[0046] Thus, gum health analysis can be performed as part of a mouth cleaning or flossing routine.

[0047] Thus, in each of these devices, the controller can determine soft tissue characteristics, and optionally, indicators of gum health, during an oral care routine.

[0048] The present invention also provides a computer-implemented method for monitoring intra-oral soft tissue characteristics, the computer-implemented method comprising: controlling an actuator to impart motion to at least one sensing element of the oral cavity monitoring head to drive the at least one sensing element towards and away from the soft tissue surface; receiving a force, strain or motion signal obtained by monitoring a force, strain or motion associated with at least one sensing element; and analyzing the force or strain signals or the movement to derive viscoelastic material properties of the material in contact with the at least one sensing element.

[0049] The method may also include deriving an indicator of gum health based on the viscoelastic material properties.

[0050] The invention also provides a computer program comprising computer program code which, when executed on a controller of a system for monitoring intra-oral soft tissue properties as defined, performs the above method.

[0051] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. [Brief description of the drawings]

[0052] For a better understanding of the present invention and to show more clearly how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings in which:

[0053] [Figure 1] FIG. 1 shows the stress-strain response of a sample subjected to a sinusoidal tapping load. [Diagram 2] FIG. 2 shows a system for monitoring soft tissue properties, for example for assessing gum health. [Diagram 3] FIG. 3 shows a schematic of a toothbrush head including bristles and gum health sensing elements. [Figure 4] FIG. 4 illustrates a schematic of a dental cleaning mouthpiece including cleaning bristles and a gum health sensing element. [Diagram 5] FIG. 5 shows an arrangement of three sensing elements at different heights to the surface of the teeth and gums. [Figure 6] FIG. 6 shows various sensing elements at various angles. [Figure 7] FIG. 7 shows a measure of differential stiffness over time as gum recession progresses. [Figure 8] FIG. 8 shows a device with an oral irrigator function combined with a toothbrush head. [Figure 9] FIG. 9 shows an arrangement that can perform both air flossing and liquid mouthwash functions. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] The present invention will now be described with reference to the drawings.

[0055] It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the devices, systems, and methods, are for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the devices, systems, and methods of the present invention will become better understood from the following description, the appended claims, and the accompanying drawings. It should be understood that the figures are schematic representations only and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the figures to indicate the same or similar parts.

[0056] The present invention provides a system for monitoring intra-oral soft tissue properties. An oral monitoring head includes at least one sensing element, such as a probe that can be placed between cleaning bristles. A tapping motion is applied to the at least one sensing element, and a force, strain, or motion associated with the at least one sensing element (such as a reaction force from the soft tissue) is monitored to generate a force, strain, or motion signal. From this signal, viscoelastic material properties of a material in contact with the at least one sensing element are derived. In one example, an indication of gum health can be provided.

[0057] The present invention may be implemented as a device solely for intraoral soft tissue analysis, as part of a toothbrush, cleaning mouthpiece, oral irrigator, or flossing system, or as part of a system that combines two or more of the following: tooth brushing, oral irrigation (e.g., using liquid), flossing (e.g., using air), and cleaning using a mouthpiece.

[0058] The present invention will be described with reference to a system for monitoring gum health, but more generally the system can be used to analyze the material properties of more general intraoral soft tissues, such as the gums, tongue, or cheeks.

[0059] FIG. 2 shows a system 100, particularly for monitoring gum health. The system 100 includes an oral monitoring head 102, which includes at least one sensing element 104 in the form of an elongated fiber or probe. An actuator 106 (such as a drive train, motor, and mechanical transmission unit in the handle or head of the system) is provided to impart motion to the at least one sensing element 104 in contact with the tissue to be analyzed. The motion is along the elongated axis of the sensing element. The actuator may be in the brush head as shown, but may also be provided by the toothbrush motor and drive train, which are typically found in the toothbrush handle.

[0060] A sensor 108 monitors the response from the soft tissue. In a preferred set of embodiments, the sensor is a force or strain sensor for monitoring force or strain associated with at least one sensing element 104 and generates a force or strain signal.

[0061] However, the response may also be evaluated using a motion sensor. For example, an accelerometer (and optionally also a gyroscope) can be used to monitor the movement of the sensor tip, thereby monitoring the displacement, velocity and acceleration of the sensor. This movement is affected by the nature of the soft tissue, i.e. the damping it provides to the movement of the sensor tip caused by a particular tip actuation profile. The sensor is therefore typically a force sensor, a strain sensor or a motion sensor.

[0062] Typically, the sensing and actuation functions are separate, but this is not necessary: ​​for example, by using piezoelectric materials, self-sensing actuators can be formed.

[0063] The signals of interest are those generated while the sensing element 104 remains in contact with the gum tissue, since once it is retracted such that contact is lost, there is no information to gather.

[0064] A controller 110 generates drive signals to the actuators 106 and also receives force or strain signals from the sensors 108. The controller 110 analyses at least the force or strain signals to derive mechanical or viscoelastic material properties, such as tissue stiffness, of the material in contact with the sensing elements 104. Based on these viscoelastic material properties, an indication of gum health GHI is provided.

[0065] The stiffness measurements can be synchronized with the movement of the sensing element, for example to measure stiffness at maximum depth of travel.

[0066] Thus, the present invention provides a system for monitoring gum health by probing the gums with sensing elements 104 and analyzing the force, strain, or movement to derive a health indicator. For example, the gum health indicator may simply be an indicator of health or an indicator of inflammation, although in more advanced embodiments described below, a severity of gum health may be obtained. The system may also provide an indicator or even a measure of gum recession in some further embodiments.

[0067] 2 shows an improved embodiment in which a camera 112 is also provided for taking intraoral images. By way of example, the images can be used to identify the gum color of the gum area probed by the sensing element 104. For example, the integrated camera uses micro-CMOS technology. Of course, the camera 112 may also be part of a separate device, such as a home intraoral scanner or a smartphone camera.

[0068] 2 also shows an improved embodiment in which an inertial monitoring unit 114 is also provided. This can be used to identify the location of the gums to which the gum health indicators relate. The inertial monitoring unit 114 acts as a motion or position sensor to detect the location of the oral cavity monitoring head.

[0069] The location information can also be used to provide alignment between captured camera images and the location of the oral monitoring head. For example, the image information combined with the location information can enable the system to determine when the oral monitoring head is on the gums or teeth, or when it has actually moved beyond the tooth / gum boundary.

[0070] The inertial monitoring unit includes an accelerometer and a gyroscope, and can be used to track position and movement in 3D space using a 6-axis measurement unit.

[0071] For example, the force or strain sensing function may use a piezoelectric sensor, strain gauge, fiber Bragg grating, or Fabry-Perot sensor to obtain the force or strain pulse shape upon contact of the tip of the sensing element 104 with the target area (i.e., gums or teeth) or to obtain the deformation characteristics of the sensing element in response to a sinusoidal excitation.

[0072] Suitable drive schemes include an impulse drive signal, an increasing or decreasing frequency sweep, or a periodic up-down or down-up frequency sweep, which is enabled by the controller when actuating the sensing element. The frequency sweep may be, for example, in the frequency range of 10-1000 Hz, and during the sweep, the response of the sensor signal is fed back to the controller.

[0073] The relationship between the actuator and sensor signals allows the viscoelastic material properties to be determined.

[0074] In impulse testing, an impulse motion of theoretically infinitesimally small duration is applied to a probe in contact with the gums, which induces a nearly flat response in the frequency domain (i.e., constant amplitude). Force measurements can be made either at the tip of the sensing element or in the head (i.e., at the proximal end of the sensing probe). This impulse test is therefore similar to the impact hammer modal test.

[0075] Frequency sweep testing is similar to shaker modal testing, where either periodic vibration or random signal excitation can be applied.

[0076] In both the frequency sweep and impulse cases, a tapping motion is created by moving the probe in and out, keeping the tip as close to stationary as possible in contact with the target surface (the gums). In both cases, the time and frequency domain response provides an indication of resonant frequencies and damping levels, allowing the stiffness and viscoelastic properties of the target surface to be identified.

[0077] For example, the sensing element may have a bristle structure and may in fact perform a cleaning function in the same way as other non-sensing bristles on the toothbrush head (see below). For example, the sensing bristles may include piezoelectric polymer fibers, fiber Bragg gratings, or fiber optic based Fabry-Perot interferometer sensors.

[0078] The actuator may be located in the oral cavity monitoring head or may be in the handle portion of the device with the drive train between the handle portion and the oral cavity monitoring head.

[0079] By activating the sensing element with a controlled mechanical or motion stimulation, e.g., in tapping mode, and then analyzing the response of the sensor signal in the time and frequency domain, it can first be determined whether a tooth or gum surface has been contacted. These target areas have very distinct stiffness and damping characteristics. Secondly, if a gum surface has been contacted, the condition of the gums (healthy or inflamed) can be assessed.

[0080] Variations in gum condition can be detected by differential changes in stiffness (or pulse shape time / frequency domain characteristics), color (chromaticity coordinates from image analysis of the gums) and even texture from image analysis.

[0081] For example, gums can be assessed as healthy by deriving a health ratio H=r / V related to gum health, where the vibration signal characteristic parameter is represented by V (e.g., first harmonic frequency, amplitude, or pulse width) and the chromaticity coordinate is represented by r. This ratio H is compared to a threshold below which the gums are considered healthy and above which they are assessed as inflamed.

[0082] The chromaticity coordinates represent the red component of the color (here r=0 for blue or green, and r=1 for red).

[0083] The nature of the gum health indicator depends on the accuracy of the location sensing available.

[0084] For example, in relatively coarse place sensing, the minimum gum stiffness measured in a session over time may be tracked and the ratio H may be evaluated and compared to a specified threshold to conclude an overall healthy gum condition. For example, coarse place sensing may be used to ensure that the mouth is adequately covered during a brushing session, allowing the stiffness measurements obtained to be compared to previous brushing sessions.

[0085] For more precise location sensing, contact location can be determined based on the location of the sensing element. By scanning the mouth with this system, gum location can be mapped onto a 3D model and tracked over time. This allows for localized assessment of gum health and even gum recession based on the location of the gum / tooth border.

[0086] To operate the system of FIG. 2, a user (e.g., an oral health care professional) holds the system against a tooth or gum surface. The sensing element is moved across the tooth / gum boundary. Tapping excitation encourages periodic impacts of the sensing element in contact with the intraoral surface while moving the sensing element, which results in an impact-based analysis. Alternatively (or additionally), the sensing element is held stationary at one end in contact with the target surface and subjected to a sinusoidal excitation at the opposite end to perform a dynamic mechanical analysis (DMA). These analysis modes are described above.

[0087] When using an inertial monitoring unit, the sensing element outputs and the location information derived from the IMU are synchronized and recorded. The signals can be analyzed by the standalone system probe's controller or the data can be transferred for processing on a connected smartphone or computer, or remotely in the cloud.

[0088] The above examples show a system specifically for analyzing gum health, however, the system may be combined with an oral care device whose primary purpose is to perform an oral care routine.

[0089] 3 shows a schematic representation of a toothbrush head including the bristles 120 and sensing element 104 of the above system. The sensing element 104 is thus integrated into the toothbrush head. The tip of the sensing element is positioned in a suitable position between or near the bristle tufts 120 of the toothbrush head. The sensing element 104 protrudes from the head in the same (or approximately the same) direction as the toothbrush bristles 120, and in fact the sensing element itself can perform the same cleaning function as a bristles without sensing function.

[0090] During operation, the sensing element signal is monitored in the same manner as above, and the gums are assessed by a similar signal trace.

[0091] Gum assessment may be performed during regular oral cleaning sessions (whether using impulse testing or short-term frequency sweep testing). In the case of (powered) toothbrushes, one or more or all bristles may be sensing bristles with dual brushing and sensing functions.

[0092] A trace is taken as the user moves the toothbrush head around the mouth. If the optional location sensing described above is provided and the system is for mapping the location of gums and teeth, location sensing can be used to identify when the user has moved the toothbrush head past the tooth / tooth boundary. For example, location sensing can be used to identify when vertical movement has occurred and the probe has likely crossed the tooth / gum boundary. The location of the gums and teeth can be evaluated as part of the mapping function.

[0093] To improve performance, guidance on the use of the probe (e.g. device positioning and the path to follow) could be provided via the app, and dedicated modes could be built into the device to perform regular gum scanning and assessment before and after standard brushing sessions.

[0094] FIG. 4 shows a schematic diagram of a dental cleaning mouthpiece incorporating multiple sensing elements 104 (for different locations on the gums) of the above system.

[0095] 4 shows one channel of a mouthpiece-based dental cleaning system. The system 200 includes a mouthpiece 202 for insertion into a user's mouth and an exterior portion 210 for positioning outside and in front of the user's mouth. For example, the exterior portion 210 serves as a handle for the system.

[0096] The mouthpiece includes a first U-shaped (or equivalently C-shaped) channel 204 for receiving the teeth of one jaw and a second U-shaped channel for receiving the teeth of the other jaw. Each channel defines an arch of the mouthpiece. In Figure 5, for example, the first channel 204 is viewed downwards, opening upwards, while the second channel is open downwards and is on the underside.

[0097] The mouthpiece may alternatively be J-shaped to fit generally to one side of the jaw. In cross section, each channel has a U-shape that defines a channel opening for receiving the teeth. However, two channels may be combined into one structure to create an H-shaped cross section with upper and lower channel openings.

[0098] The entire mouthpiece is bitten by the user with the teeth in two channels. The system may instead have only one channel, in which case cleaning is done one jaw at a time.

[0099] The channel 204 includes a cleaning arrangement 206, such as bristles that face the user's teeth within the mouthpiece channel, for example, the bristles are driven parallel to the tooth surfaces, as indicated by the arrows.

[0100] The outer part 210 has an actuator 212 for applying movement to the channel shaped inner and / or outer arches (relative to a fixed base). In the case of a system with two U-shaped channels, a shared actuator can be used.

[0101] The sensing elements are part of each mouthpiece arch, with at least one sensing element 104 being within or adjacent to the bristles of the cleaning arrangement.

[0102] In another embodiment (not shown), gum health analysis can be incorporated into the cleaning mouthpiece. In this case, multiple sensing elements are distributed at appropriate locations within the mouthpiece arch (as the mouthpiece does not move around the oral cavity) and the sensing elements are within or adjacent to the bristle arrangement. Due to the limited movement around the oral cavity, location sensing is limited or unnecessary.

[0103] Again, some or all of the bristles of the mouthpiece may have a dual function of brushing and sensing. As with the previous embodiment, the oral care device may incorporate a dedicated mode for scanning and assessing gum health periodically before and after a mouthpiece cleaning session.

[0104] The sensing elements may have different configurations, for example, the sensing elements can be in different positions and, optionally, in different orientations relative to the teeth or gums, One sensing element orientation and position is positioned to measure gum tissue (e.g., positioned near the gum line), while another orientation is for measuring the surface of the teeth.

[0105] FIG. 5 shows three sensing elements 104 at different heights to the teeth and gum surface using a mouthpiece arch. By tracking the differential measured stiffness over time between different sensing elements, gum recession can be detected based on the sensing element transitioning from detecting gum tissue to detecting the tooth surface. If gum recession occurs, one of the gum sensing elements will begin measuring stiffness corresponding to the teeth, which will cause the differential stiffness measure to decrease. If a critical threshold is reached, an automated triage alert is sent to the dentist advising the user to see a dentist or to schedule an appointment.

[0106] Figure 6 shows different sensing elements at different angles, so some are pointing towards the tooth surface, some towards the gum / tooth border and some towards the gums.

[0107] 7 shows a measure of differential stiffness over time, i.e., the difference in stiffness, which may be a ratio, between a sensing element positioned for detecting teeth and a sensing element positioned for detecting gums.

[0108] At a first time point t1, gum recession begins to occur. At a second time point t2, an alert is triggered.

[0109] Gum health analysis may also be applied to oral flossing and / or cleaning systems.

[0110] FIG. 8 shows a device with oral irrigator functionality combined with a toothbrush head 102 .

[0111] The toothbrush head 102 includes a sensing element 104 and an actuator 106, as previously described (other components not shown to keep the illustration simple).

[0112] The system further includes a nozzle 128, which is also applied to the teeth and gums when the head 102 is used. The nozzle 128 is the distal end of a fluid delivery tube 130. The proximal end may receive fluid from a reservoir 136 or may use outside air as the delivery fluid.

[0113] A pump 132 is used to pump fluid through the fluid delivery tube 130 to the nozzle 128. In this embodiment, the fluid reservoir 136, pump 132, and sensor 134 are part of the toothbrush; however, these components may also be separate from the toothbrush and connectable by the fluid delivery tube 130.

[0114] In this example, the combined toothbrush and oral irrigator function includes its own sensing function (in addition to sensing gum health) and sensor 134 is positioned to sense the pressure in or flow rate along fluid delivery tube 130. In one example, sensor 134 is a pressure sensor. However, sensor 134 may also be a flow sensor or a combination sensor capable of measuring flow and pressure in the fluid delivery tube.

[0115] The sensing feature provides an alternative or additional means for detecting when the head is in contact with a tooth or gum surface. In particular, flow resistance at the nozzle 128 affects flow rate and pressure. For example, soft gum tissue closes the nozzle more effectively than hard tooth tissue, so that higher pressure and lower flow rate are observed when there is contact with the gums. When there is no contact, for example when the nozzle is aligned with a tooth gap, lower pressure and higher flow rate are observed. This approach is known, for example, for controlling the delivery of mouthwash depending on the position of the head, i.e., whether the head is aligned with a tooth or with a tooth gap.

[0116] 8 shows the delivery of liquid from a reservoir 136, such liquid delivery in oral irrigators is known, as is air delivery in, for example, air flossing systems.

[0117] 9 shows an arrangement in which either air or liquid can be delivered to the delivery tube 130. This allows for both air flossing and liquid mouthwash functions. In this embodiment, the system is not used for tooth brushing.

[0118] The pump 132 can provide pumping of air through an inlet 140 and a switch 142 that switches between the fluid reservoir 136 and the inlet 140. The switch 142 selects whether the pump 132 delivers ambient air or liquid from the reservoir through the fluid delivery tube 130. Alternatively, a second fluid reservoir containing air (or any gas) can be used instead of the inlet 140. Also, more than one inlet 140 can be used to allow the pump to continue pumping air even if one of the inlets is blocked by the user's hand.

[0119] In this design, gum health analysis is integrated into the mouthwash or flossing head.

[0120] In the above examples, health analytics integrated into an oral care device having another primary function can be used to analyze gum health during regular cleaning, brushing sessions, or air flossing sessions.

[0121] In embodiments using motion sensing and / or image-based location sensing, the device can be used to derive a 3D profile of the teeth and gums. Based on a daily oral care routine using the device to analyze gum health, the device can be used to detect the location of the gums and teeth. Repeated analysis over time can iterate and refine the profile to obtain a 3D scan-like file of the teeth and gums.

[0122] Guided brushing (or other oral care routine) techniques can be used to improve the 3D profile, requiring the user to follow a specific pattern when brushing to facilitate location and allow estimation of the occlusal vertical dimension of the teeth. For example, by asking the user to brush from the gums upwards, three different sets of spectra are recorded: gums, teeth, and free space, indicating the edge or height of the teeth. The user may then be instructed to move on to the next tooth, etc.

[0123] The captured sensor data can be combined (e.g., by overlay) with a 2D photograph, so that missing information from one modality (e.g., camera) is provided by another modality (e.g., sensing).

[0124] Variations of the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and singular elements do not exclude a plurality.

[0125] The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0126] Those skilled in the art will be able to readily develop a controller to perform the methods described herein. The controller can be implemented in a variety of ways using software and / or hardware to perform the various functions required. A processor is one example of a controller that employs one or more microprocessors that are programmed using software (such as microcode) to perform the functions required. However, the controller may be implemented without regard to the employment of a processor, and may be implemented as a combination of dedicated hardware to perform some functions and a processor (e.g., one or more programmed microprocessors and associated circuitry) to perform other functions.

[0127] Examples of controller components that may be employed in various embodiments of the present disclosure include, but are not limited to, conventional microprocessors, application specific integrated circuits (ASICs), and field programmable gate arrays (FPGAs).

[0128] In various implementations, a processor or controller may be associated with one or more storage media, such as volatile and non-volatile computer memory, such as RAM, PROM, EPROM, and EEPROM. The storage media may be encoded with one or more programs that, when executed on the one or more processors and / or controllers, perform the necessary functions. The various storage media may be fixed within the processor or controller, or may be transportable such that one or more programs stored thereon may be loaded into the processor.

[0129] The computer program may be stored / distributed on any suitable medium, such as an optical storage medium or a solid-state medium, supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless communication systems.

[0130] It should be noted that when the term "adapted to" is used in the claims or description, it is intended to be equivalent to the term "configured to."

[0131] Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. 1. A system for monitoring intraoral soft tissue characteristics for monitoring gum health, the system comprising: an oral cavity monitoring head including at least one sensing element; an actuator for imparting movement to the at least one sensing element in contact with the gum; a force, strain, or motion sensor for monitoring a force, strain, or motion associated with the at least one sensing element and generating a force, strain, or motion signal; and a controller, the controller comprising: Controlling the actuator; receiving the force, strain, or motion signal; analyzing the force, strain or movement signals to derive viscoelastic material properties of the gum in contact with the at least one sensing element; The system provides an indication of gum health based on the viscoelastic material properties.

2. The system of claim 1 , wherein the controller further receives intraoral images.

3. 3. The system of claim 2, further comprising an imaging camera for capturing the intraoral image.

4. A system according to any one of claims 1 to 3, comprising a head movement or position sensor for detecting the location of the oral cavity monitoring head, for example the head movement or position sensor comprising an inertial measurement unit including an accelerometer and a gyroscope.

5. The system of claim 1 , wherein the controller analyses the force, strain or motion signals in the time and frequency domains.

6. The system of claim 1 , wherein the controller determines a minimum gum stiffness during a monitoring period.

7. 7. The system of claim 1, wherein the controller determines whether the at least one sensing element is in contact with a tooth surface or a gum surface and determines the indication of gum health only if the sensing element is in contact with a gum surface.

8. The system of claim 1 , wherein the controller controls the actuator to apply a frequency sweep to the movement imparted to the at least one sensing element.

9. The force, strain, or motion sensor comprises: Piezoelectric sensors, Strain gauges, Fiber Bragg Grating, accelerometer, Fabry-Perot sensor, The system of claim 1 , further comprising one or more of the following:

10. 1. An electric toothbrush device for performing an oral care routine of brushing teeth, comprising: A handle portion, a brushing head including a bristle arrangement; A system according to any one of claims 1 to 9; Including, An electric toothbrush device, wherein the at least one sensing element is part of the brushing head, and the at least one sensing element is within or adjacent to the bristle arrangement.

11. 1. An electric brushing mouthpiece device for performing an oral care routine of mouthpiece teeth cleaning, comprising: Mouthpiece arch and a brushing arrangement including a bristle arrangement within said mouthpiece arch; A system according to any one of claims 1 to 9; Including, The at least one sensing element is part of the mouthpiece arch, and the at least one sensing element is within or adjacent to the bristle arrangement.

12. 1. An oral irrigator device for performing an oral care routine, which is oral cleaning or flossing, comprising: A handle portion, An oral irrigator or flossing head; a squirt tube between the handle and the oral irrigator or flossing head; A system according to any one of claims 1 to 9; Including, An oral irrigator device, wherein the at least one sensing element is part of the oral irrigator or flossing head.

13. When executed in a controller of a system for monitoring intra-oral soft tissue properties according to any one of claims 1 to 9, controlling an actuator to impart motion to at least one sensing element of an oral monitoring head to drive the at least one sensing element towards and away from the gingival surface; receiving a force, strain, or motion signal obtained by monitoring a force, strain, or motion associated with the at least one sensing element; - analyzing the force, strain or movement signals to derive viscoelastic material properties of the gum in contact with the at least one sensing element; and providing an indication of gum health based on said viscoelastic material properties.

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