WO2024153442A1

WO2024153442A1 - Toothbrush

Info

Publication number: WO2024153442A1
Application number: PCT/EP2023/087833
Authority: WO
Inventors: Andreas Philipp HASSLER; Eva-Maria OELWEINER; Michael Cernusca; Markus Arzberger
Original assignee: Ams-Osram Ag; Ams-Osram International Gmbh
Priority date: 2023-01-16
Filing date: 2023-12-27
Publication date: 2024-07-25

Abstract

A toothbrush (2) with improved capabilities for efficient and reliable dental care and oral hygiene comprises a handle (4) and a cleaning head (6), wherein a short-wave infrared sensor (16) comprising an infrared light source (18) and an infrared light detector (20) is integrated into the cleaning head (6), and wherein the short-wave infrared sensor (16) is connected or connectable to a processing unit (22) which is configured to derive, based on an output signal of the short-wave infrared sensor (16), information suitable for an analysis and/or a classification of tissues in an oral cavity of a user of the toothbrush (2).

Description

TOOTHBRUSH

DESCRIPTION

TECHNICAL FIELD

The invention relates to a toothbrush with a handle and a cleaning head . The invention also relates to a corresponding method of operation .

BACKGROUND

Toothbrushes are known in various configurations . In particular, there are electric toothbrushes with an electrically movable cleaning head, the cleaning head usually comprising an array of bristles . Such a cleaning head is also known as bristle head or brush head . A lot of research is involved in optimi zing the bristles arrangement , but there are other aspects of a toothbrush as well which are responsible for ef ficient and reliable dental care and oral hygiene .

SUMMARY

An obj ective of the present invention is to provide a toothbrush with improved capabilities for ef ficient and reliable dental care and oral hygiene .

In particular, an aim is to provide an additional benefit over and above the normal process of brushing or cleaning teeth, which benefit is feasible for various embodiments of toothbrushes . The toothbrush shall be lightweight with a small form factor and low energy consumption ( i . e . , long battery li fe ) . A corresponding method of operation shall be given as well .

According to the invention, the obj ective is met by a toothbrush according to claim 1 . The corresponding method is speci fied in claim 20 . Accordingly, there is a toothbrush with a handle and a cleaning head, wherein a short-wave ( length) infrared ( SWIR) sensor comprising an infrared light source and an infrared light detector is integrated into the cleaning head, and wherein the short-wave infrared sensor is connected or connectable to a processing unit which is configured to derive , based on an output signal of the short-wave infrared sensor, information suitable for an analysis and/or a classi fication of tissues in an oral cavity of a user of the toothbrush .

In a preferred embodiment , the processing unit is integrated into the handle of the toothbrush . In an alternative embodiment the processing unit may be an external or remote unit , in particular a smartphone App or computer program . In this case the toothbrush may comprise circuity which is configured to communicate via a wireless connection ( in particular WLAN or Bluetooth) with the remote processing unit and/or a database and/or a web-based service , such that an evaluation or assessment of the output of the SWIR sensor happens at least partially remotely . There may also be a mixed or hybrid implementation with an elementary or core processing unit in the toothbrush which on demand may communicate with a supplementary external processing unit .

Expediently, the cleaning head comprises a plurality of bristles , wherein the short-wave infrared sensor is preferably arranged in a blank between the bristles .

Preferably, the cleaning head can be moved in a rotating and/or vibrating manner by means of an electric drive integrated into the toothbrush, wherein the processing unit is preferably configured to set a mode of operation for the electric drive according to information acquired from the short-wave infrared sensor . For example , a frequency of rotation or vibration may be set . Alternatively or additionally, the cleaning head may comprise a number of ultrasonic emitters , wherein the processing unit is preferably configured to set a mode of operation for the ultrasonic emitter ( s ) according to information acquired from the short-wave infrared sensor .

In a further preferred embodiment , the cleaning head comprises a phototherapy device . For example , the phototherapy device may comprise a laser emitter, in particular a vertical cavity surface emitting laser (VCSEL ) . Alternatively or additionally, the phototherapy device comprises an UV light source . Like the short-wave infrared sensor, the phototherapy device is preferably arranged in a blank between the bristles .

Expediently, the processing unit is configured to trigger or set a mode of operation of the phototherapy device according to information acquired from the short-wave infrared sensor . For example , this may comprise setting the duration of laser pulses .

In yet a further preferred embodiment , the cleaning head comprises a photoplethysmography sensor, preferably based on visible light ( in particular red light ) , which is connected or connectable to the processing unit .

In general , a plethysmograph is an instrument for measuring changes in volume within an organ or whole body (usually resulting from fluctuations in the amount of blood or air it contains ) . A photoplethysmogram ( PPG) is an optically obtained plethysmogram . To this end, a photoplethysmography sensor typically comprises a light source for illuminating the organ of tissue of interest , and a light detector sensing a reflected and/or a transmitted portion of the emitted light .

In a preferred application, the processing unit is configured to derive from a measurement signal of the photoplethysmography sensor an oxygen concentration in a tissue of an oral cavity .

In particular, the processing unit may be configured to trigger a measurement with the photoplethysmography sensor . That is , the photoplethysmography sensor is preferably only activated on demand which saves battery li fe .

In an expedient advancement of said idea, the processing unit is configured to analyze oral tissue conditions and/or to detect caries from information acquired from the short-wave infrared sensor in combination with information acquired from the photoplethysmography sensor .

Generally, the processing unit may be configured to switch between a number of cleaning, therapy, and/or sensing programs according to information acquired from the shortwave infrared sensor, and optionally from further sensors .

In another preferred application, the processing unit is configured to derive an oral cleaning or therapy recommendation for a user of the toothbrush and to indicate said recommendation with the help of an associated indicator device . For example , this may be a simple LED signal at the handle of the toothbrush, or an information sent to and visuali zed on a smartphone . Alternatively or additionally, there may be a haptic and/or an acoustic signal ( feedback, recommendation, warning, or information) . For example , a recommendation guides the user how to use / handle the toothbrush in an optimal way regarding timing and location of the toothbrush movement .

Typically, the short-wave infrared detector comprises an infrared light source and an infrared detector for reflected infrared light . In a prefeed embodiment the infrared detector comprises a single channel (pixel ) or j ust a few channels on a small area and therefore has as small form factor . With respect to the method, an output signal of the shortwave infrared sensor is used for an analysis and/or a classi fication of tissues in an oral cavity of a user of the toothbrush . Preferably a mode of operation for an electric drive , a further sensor, or a treatment device integrated into the toothbrush is set according to information acquired from the short-wave infrared sensor .

What has been said with respect to the device may analogously be applied to the method, and therefore need not be repeated here . Method embodiments and details have a counterpart in the device and vice versa .

With the help of a short-wave infrared ( SWIR) sensor integrated in the toothbrush cleaning head, a processing unit either within the toothbrush or located externally and queried remotely recogni zes which kind of tissue the cleaning head is on ( tissue classi fication) . This way, the toothbrush can adapt its cleaning program to the speci fic requirements of the tissue , for example activating a cleaning program for the teeth or using a massage program for the gums . Another example application would be that the toothbrush recogni zes when it is on the gum and now triggers a measurement with an additional oxygen sensor such that the tissue information is used for saving battery li fe . Moreover, when the system detects the cleaning head is on the teeth, SWIR based caries sensing/monitoring can be conducted .

To summari ze so far, the invention is based on the integration of a short-wave infrared ( SWIR) sensor-based measurement system into the toothbrush cleaning head for analyzing / di f ferentiating between oral cavity tissues ) and the control of di f ferent programs / operation modes through the acquired information of the tissue .

More speci fically, a calculation algorithm implemented in a processing unit is used to distinguish between the di f ferent types of tissue . The algorithm decides which actions are to be carried out depending on the tissue type . For example , the starting or switching of the brushing program or the triggering of a measurement with another sensor, which can also be integrated in the toothbrush head, such as another biosensor. Furthermore, the algorithm can be used to trigger treatments when the sensor head is in contact with the affected tissue. For example, a low-level laser therapy that inhibits inflammation would be conceivable.

In summary, possible applications of a SWIR sensor integrated into a toothbrush comprise:

• Using SWIR sensor information to determine the different tissues in the oral cavity.

• Using the tissue information for switching modes of operation, e.g. cleaning, therapy, or sensing programs.

• Using SWIR sensor information to additionally assess presence of caries.

• Using tissue information to trigger a measurement with another sensor (e.g., an oxygen sensor for gingivitis detection) .

• Analyzing oral tissue condition using SWIR in combination with other biosensors.

• Using tissue information to trigger treatments of the oral tissue (e.g., low-level laser therapy) .

• Guiding the user how to use / handle the toothbrush in an optimal way regarding timing and location of the toothbrush movement.

Advantages related to the various embodiments of the invention comprise, depending on the variant:

• The smart selection of different cleaning, therapy, and sensing programs, and switching between them.

• Optionally, the triggering of an oral treatment, e.g. an anti-inflammatory therapy.

• Additionally, using sensor signal for assessing pathological dental regions (e.g., caries detection) .

• Additionally, the intelligent triggering of measurements with other sensors such as an oxygen sensor. • The early detection of gingivitis and providing a warning system by using an algorithm for interpretation of the measured oxygen values.

• Extended toothbrush battery life

BRIEF DESCRIPTION OF THE DRAWINGS

Expedient embodiments of the invention are now discussed with reference to the accompanying drawings.

FIG. 1 shows a side view of a toothbrush.

FIG. 2 shows a plan view of a cleaning head of the toothbrush according to FIG. 1.

FIG. 3 shows a diagram with example spectra obtained by a short-wave infrared (SWIR) sensor in an oral cavity.

DETAILED DESCRIPTION

FIG. 1 shows a partially sectioned side view of toothbrush 2. The toothbrush 2 comprises a handle 4 and a cleaning head 6. The cleaning head 6, a plan view of which is shown in FIG. 2, comprises a plurality of bristles 8 attached to a main body of the cleaning head 6. The cleaning head 6 may be movable in a rotating or vibrating manner by virtue of an electric drive 10 integrated into the handle 4. The handle 4 also holds a (preferably rechargeable) battery 12 as an energy storage for the electric drive 10 and a corresponding control unit 14.

The components integrated into the handle 4 or the cleaning head 6 are only schematically indicated in FIG. 1.

Additionally or alternatively to the movable support of the cleaning head 6 and the associated electric drive 10, a number of ultrasonic emitters 30 may be integrated into the cleaning head 6. Such ultrasonic emitters 30 may provide a cleaning effect (e.g., loosening and detachment of plaque) in addition to or even without the bristles 8. To provide extended possibilities with respect to oral or dental care and related diagnosis, a short-wave infrared (SWIR) sensor 16 is integrated into the cleaning head 6. The SWIR sensor 16 comprises an infrared light source 18, emitting light in the short-wave infrared region, in particular with a wavelength in the range from 1.000 nm to 3.000 nm. The emitted light is directed along the direction of the bristles 8 towards the oral region (e.g., teeth, gums, tissue) to be cleaned by the bristles 8. The SWIR sensor 16 further comprises an infrared light detector 20 which is configured to detect a reflected portion of the emitted infrared light, i.e., after reflection at the respective oral region under treatment. This light detector 20 preferably comprises a single channel (pixel) or just a few of them. The entire SWIR sensor 16 therefore has a small form factor and fits into a blank or gap area between the bristles 8.

A processing unit 22 for assessing and analyzing the output of the SWIR sensor 16 may be integrated into to handle 4. The processing unit 22 may either be a part of the control unit 14 or a separate unit interacting with the control unit 14. The battery 12 for the electric drive 10 may also act as an energy supply for the SWIR sensor 16 and related circuity.

In a possible variation, the processing unit 22 in the handle 4 only comprises core routines for the evaluation of the sensor signals and/or the control of the electric drive 10, while more sophisticated evaluations take place in an external evaluation unit or App with which the processing unit 22 in the handle 4 interacts over a wireless connection, in particular Bluetooth or WLAN. The external device such as a smartphone may also be used for the visualization of measurement results and/or derived oral care recommendations.

FIG. 3 shows that the SWIR sensor 16 output allows for a classification or specification of tissues in the oral cavity. In the example, oral reflectance spectra (reflectance over wavelength) are obtained for four different oral tissues: dentin, detin caries, enamel, enamel caries. As the spectral curves can clearly be distinguished, conversely, the detection and classi fication of tissue material is possible based on the measured spectra . This in turn allows for various application as discussed below .

The invention therefore involves the use of a SWIR sensor 16 to analyze the composition of the tissue ( s ) in the oral cavity . The properties of the underlying/ scanned tissue are analyzed with the aid of a reflection measurement . In contrast to full-scale SWIR imaging, preferably only one pixel ( in a defined small area ) is analyzed in order to determine the underlying properties and to derive necessary activities from this . This ensures a small form factor of the sensor .

An example for the usage of tissue information would be to start the cleaning program of a toothbrush 2 only when the cleaning head 6 is located on a tooth, which could signi ficantly extend the battery li fe , in particular for ultrasonic toothbrushes . To this end, the processing unit 22 for the SWIR sensor 16 suitably interacts with the control unit 14 for the electric drive 10 or the ultrasonic emitter 30 .

Another example would be to start with a measurement from an additional sensor attached to the cleaning head 6 , for example , when the cleaning head 6 is at the gingiva . This additional sensor could be a biosensor, in particular a photoplethysmography sensor 28 working in the range of visible (preferably red) light . For example the additional sensor may be used to determine the oxygen concentration in the gingiva in order to subsequently determine the level of a potential inflammation of the tissue . The information of the SWIR sensor 16 could be used as well to identi fy pathological dental tissue / structure / substance or caries .

In particular, the obtained information can further be used to make statements about the health of the gums , e . g . early detection of gingivitis . A possible user feedback could be a recommendation for a professional oral hygiene .

In an alternative or additional application, The SWIR sensor 16 can be used to trigger a therapy, like a phototherapy, in particular a low-level laser therapy . In this case the af fected tissue is illuminated with light having speci fic wavelengths and energy . A positive accelerating ef fect of these therapies in wound healing may be expected . Another possible treatment would be the usage of ultraviolet (UV) light inside the oral cavity for virus inactivation . In FIG . 2 such an application is schematically indicated by an optional phototherapy device 26 , again placed in a gap between the bristles 8 .

While the description has so far focused on the preferred case of a SWIR sensor 16 , that is an IR sensor operating in the short-wave ( length) infrared ( IR) range , the SWIR sensor 16 may in general be substituted by an IR sensor operating in another or in a broader IR region .

LIST OF REFERENCE SIGNS toothbrush 2 handle 4 cleaning head 6 bristle 8 electric drive 10 battery 12 control unit 14 short-wave infrared ( SWIR) sensor 16 light source 18 light detector 20 processing unit 22 phototherapy sensor 26 photoplethysmography sensor (biosensor ) 28 ultrasonic emitter 30 indicator device 32

Claims

1. A toothbrush (2) with a handle (4) and a cleaning head (6) , wherein a short-wave infrared sensor (16) comprising an infrared light source (18) and an infrared light detector (20) is integrated into the cleaning head (6) , and wherein the short-wave infrared sensor (16) is connected or connectable to a processing unit (22) which is configured to derive, based on an output signal of the short-wave infrared sensor (16) , information suitable for an analysis and/or a classification of tissues in an oral cavity of a user of the toothbrush ( 2 ) .

2. The toothbrush (2) according to claim 1, wherein the processing unit (22) is integrated into the handle (4) .

3. The toothbrush (2) according to claim 1 or 2, comprising circuity which is configured to communicate via a wireless connection with a remote processing unit and/or a database.

4. The toothbrush (2) according to any one of the preceding claims, wherein the cleaning head (6) comprises a plurality of bristles (8) , and wherein the short-wave infrared sensor (16) is preferably arranged in a blank between the bristles (8) .

5. The toothbrush (2) according to any one of the preceding claims, wherein the cleaning head (6) can be moved in a rotating and/or vibrating manner by means of an electric drive (10) integrated into the toothbrush (2) .

6. The toothbrush (2) according to claim 5, wherein the processing unit (22) is configured to set a mode of operation for the electric drive (10) according to information acquired from the short-wave infrared sensor (16) .

7. The toothbrush (2) according to any one of the preceding claims, wherein the cleaning head (6) comprises a number of ultrasonic emitters (30) .

8. The toothbrush (2) according to claim 7, wherein the processing unit (22) is configured to set a mode of operation for the respective ultrasonic emitter (30) according to information acquired from the short-wave infrared sensor (16) .

9. The toothbrush (2) according to any one of the preceding claims, wherein the cleaning head (6) comprises a phototherapy device (26) .

10. The toothbrush (2) according to claim 9, wherein the phototherapy device (26) comprises a laser emitter, in particular a vertical cavity surface emitting laser.

11. The toothbrush (2) according to claim 9 or 10, wherein the phototherapy device (26) comprises an UV light source.

12. The toothbrush (2) according to any one of claims 9 to 11, wherein the processing unit (22) is configured to trigger or set a mode of operation of the phototherapy device (26) according to information acquired from the short-wave infrared sensor (16) .

13. The toothbrush (2) according to any one of the preceding claims, wherein the cleaning head (6) comprises a photoplethysmography sensor (28) , preferably based on visible light, which is connected or connectable to the processing unit ( 22 ) .

14. The toothbrush (2) according to claim 13, wherein the processing unit (22) is configured to derive from a measurement signal of the photoplethysmography sensor (28) an oxygen concentration in a tissue of an oral cavity.

15. The toothbrush (2) according to claim 13 or 14, wherein the processing unit (22) is configured to trigger a measurement with the photoplethysmography sensor (28) .

16. The toothbrush (2) according to any one of claims 13 to 15, wherein the processing unit (22) is configured to analyze oral tissue conditions and/or to detect caries from information acquired from the short-wave infrared sensor (16) in combination with information acquired from the photoplethysmography sensor (28) .

17. The toothbrush (2) according to any one of the preceding claims, wherein the processing unit (22) is configured to switch between a number of cleaning, therapy, and/or sensing programs according to information acquired from the shortwave infrared sensor (26) , and optionally from further sensors .

18. The toothbrush (2) according to any one of the preceding claims, wherein the processing unit (22) is configured to derive from information acquired by the short-wave infrared sensor (16) an oral cleaning or therapy recommendation for a user of the toothbrush (2) and to indicate said recommendation with the help of an associated indicator device ( 32 ) .

19. The toothbrush (2) according to any one of the preceding claims, wherein the infrared light detector (20) is configured to detect infrared light which is emitted by the infrared light source (18) and reflected by oral tissues.

20. The toothbrush (22) according to any one of the preceding claims, wherein the infrared light detector (20) comprises a single channel.

21. The toothbrush (22) according to any one of the preceding claims, wherein the processing unit (22) is configured to guide the user how to use / handle the toothbrush (22) regarding timing and location of the toothbrush movement.

22. A method of operating a toothbrush (2) according to any one of the preceding claims, wherein an output signal of the short-wave infrared sensor (16) is used for an analysis and/or a classification of tissues in an oral cavity of a user of the toothbrush (2) .