Controlling operation of intra-oral devices

Abstract

There is provided a method (100) for controlling operation of an intra-oral device (IOD) that is operable in an oral cavity of a subject. The IOD comprises an electromagnetic radiation source arrangement that is capable of causing photobiological damage to the subject when activated in a first mode. The electromagnetic radiation source arrangement may be considered hazardous if activated in the first mode outside of an oral cavity of the subject. The method helps prevent the EM radiation source arrangement from being activated outside of an oral cavity in the first mode, to reduce the likelihood that the EM radiation source arrangement will cause photobiological damage. This is achieved by images obtained using an imaging device of the IOD being analysed (102) to determine whether there are teeth present in the images. If teeth are determined to be present in the images, first signals configured to cause activation of the first mode are generated (104).

Description

[0001] 2025PF00031

[0002] 1

[0003] CONTROLLING OPERATION OF INTRA-ORAL DEVICES

[0004] FIELD OF THE INVENTION

[0005] The disclosure relates to methods and apparatus for controlling the operation of an intraoral device (IOD) that is operable in an oral cavity of a subject.

[0006] BACKGROUND OF THE INVENTION

[0007] Dental plaque is a biofdm of microorganisms that grow on surfaces within oral cavities. If plaque is not removed from the oral cavity, it can turn into tartar. Tartar build-up can cause serious dental issues such as gingivitis and periodontitis. Thus, effective removal of plaque from oral cavities is desirable.

[0008] An intra oral scanner (IOS) is operable to scan (i.e., capture images) of the inside of an oral cavity. The captured images can be viewed and / or digitally processed to determine whether plaque is present in an oral cavity of a subject of the scan.

[0009] However, identifying the presence of plaque in oral cavities can be challenging; when viewed using visible electromagnetic (EM) radiation (which may simply be referred to herein as “visible radiation” or “visible light”), plaque can be hard to see. As such, plaque may be difficult to see and / or detect in images of an oral cavity captured using standard cameras that are sensitive to visible light. To improve the visibility and / or detectability of plaque, an IOS may incorporate a source of radiation that is operable to cause Quantitative Light-induced Fluorescence (QLF) of tooth enamel and / or plaque. This fluorescence enables plaque on the tooth enamel to be visible to the human eye and / or detectable in images captured of the oral cavity, as the tooth enamel may fluoresce at a different wavelength to the plaque.

[0010] SUMMARY OF THE INVENTION

[0011] A challenge associated with sources of radiation that are operable to cause QLF is that, if misused, they can cause serious damage and harm to the human body. That is, radiation capable of inducing QLF is also capable of causing photobiological damage to soft tissue, particularly skin and eye tissue, if the soft tissue is exposed to the radiation for extended periods of time. The properties of the radiation, such as its intensity and the proximity of the EM radiation source to the irradiated zone are factors in determining the severity of the photobiological damage. Photobiological damage can lead to various adverse health effects. For example, near-UV radiation can cause skin bums or eye damage. In addition, even visible light can cause photobiological damage. For example, prolonged exposure to visible light at high intensity may cause retinal injuries.2025PF00031

[0012] 2

[0013] Embodiments of the present disclosure address these and other challenges. In particular, embodiments of the present disclosure improve the safety of an IOD comprising an EM radiation source arrangement by reducing the ability of said arrangement to cause photobiological damage. That is, the methods disclosed herein reduce the likelihood of soft tissue being exposed to hazardous radiation, which may result from potential misuse of IODS incorporating EM radiation source arrangements (e.g., by operating the IOD towards the eyes). This may be achieved by the methods enabling, based on teeth detection, the automatic triggering and / or prevention of emission of radiation from IODs that is capable of causing photobiological damage.

[0014] According to a first aspect, there is provided a computer-implemented method of controlling operation of an IOD that is operable in an oral cavity of a subject. The method comprises analyzing first images obtained by an imaging device in the IOD to determine whether one or more teeth are present in one or more of the first images. The method comprises generating one or more first signals if the one or more teeth are determined to be present in one or more of the first images, wherein the one or more first signals are configured to cause activation of a first mode of an electromagnetic, EM, radiation source arrangement in the IOD, wherein in the first mode, the EM radiation source arrangement is capable of causing photobiological damage to the subject.

[0015] Advantageously, embodiments of the first aspect help improve the safety of IODs. In particular, the embodiments help prevent the misuse of sources of EM radiation that are capable of causing, when activated in certain modes, photobiological damage. That is, such modes of the sources may only be activated if the IOD is determined to be positioned in an oral cavity.

[0016] If it is determined that teeth are not present in one or more of the first images, the method may further comprise performing an action. The action comprises one or more of: preventing activation of the first mode; not causing activation of the first mode; deactivating the first mode; deactivating the EM radiation source arrangement; and causing activation of a second mode of the EM radiation source arrangement, wherein in the second mode, the EM radiation source arrangement is not capable of causing photobiological damage to the subject (for example because the EM radiation source arrangement is deactivated, or because the intensity of the emitted light is low enough to not cause photobiological damage). Advantageously, such embodiments further improve the safety of the IOD, as they enable the IOD to revert to a safe mode of operation when teeth are not detected in the first images.

[0017] The action is performed by one or more of: preventing generation of the one or more first signals; not generating the one or more first signals; and generating one or more second signals configured to prevent activation of the first mode and / or to cause activation of the second mode.

[0018] Advantageously, such embodiments enable the IOD to prevent activation of the first mode via either implicit indications (e.g., the non-reception of first signals) or via explicit indications (e.g., the one or more second signals).

[0019] The first images may be analyzed using one or more of: a machine learning (ML) model trained to identify teeth in image data input into the ML model; computer vision techniques applied to the2025PF00031

[0020] 3

[0021] first images that are operable to identify teeth; morphological operations techniques that are operable to identify teeth in image data to which the morphological operations are applied; and a classical algorithm or any other algorithm configured to identify teeth in image data to which the algorithm is applied. Such embodiments facilitate the robust detection of teeth in the first images.

[0022] The method may be performed by one or more of: at least one processor of a cloud computing network; at least one processor of a wireless device; and at least one processor of a computing device. The one or more first signals may be output to the IOD. Advantageously, such embodiments enable the processing of the first images to be offloaded, from the IOD, to an external processing device which may be more suited (e.g., have a larger number of resources) for performing said processing.

[0023] The first mode may be activated only if the one or more first signals are received by the IOD. Advantageously, such embodiments enable the efficient usage of resources whilst operation of the IOD is robustly being controlled by the apparatus; non-reception of the first signals is an implicit and quick indication that the IOD is to prevent activation of the first mode.

[0024] The method may be performed by the IOD. The method may further comprise using the one or more first signals to activate the first mode. Advantageously, such embodiments enable the processing of the first images to be performed by the IOD, meaning the establishment of a communication channel between the IOD and an external processing device can be avoided.

[0025] In a second aspect, there is provided a method performed by an IOD that is operable in an oral cavity of a subject. The method comprises obtaining first images using an imaging device in the IOD. The method comprises transmitting the first images to a processing device external to the IOD (e.g. in a smartphone, computer, server, or a computing device in the cloud). The method comprises receiving, from the processing device, one or more first signals indicative of one or more teeth being present in one or more of the first images transmitted to the processing device. The method comprises, responsive to receiving the one or more first signals, causing activation of a first mode of an EM radiation source arrangement in the IOD. In the first mode, the EM radiation source arrangement is capable of causing photobiological damage to the subject.

[0026] Advantageously, embodiments of the second aspect help improve the safety of IODS. In particular, the embodiment help prevent the misuse of an EM radiation source arrangement that is capable of causing, when activated in certain modes, photobiological damage; said modes may only be activated if the IOD is determined to be positioned in an oral cavity. Furthermore, such embodiments enable the processing of the one or more first images to be offloaded, from the IOD, to an external processing device which may be more suited (e.g., have a larger number of resources) for performing said processing.

[0027] If one or more teeth are present in one or more of the first images, the method may further comprise performing an action. The action may comprise one or more of: preventing activation of the first mode; not causing activation of the first mode; deactivating the first mode; deactivating the EM radiation source arrangement; and causing activation of a second mode of the EM radiation source arrangement, wherein in the second mode, the EM radiation source is not capable of causing photobiological damage to2025PF00031

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[0029] the subject (for example because the EM radiation source arrangement is deactivated, or because the intensity of the emitted light is low enough to not cause photobiological damage). Advantageously, such embodiments further improve the safety of the IOD, as they enable the IOD to revert to a safe mode of operation when teeth are not present in one or more of the first images.

[0030] In the first and second aspects, the EM radiation source arrangement may be further capable of causing tooth enamel (or any other plaque-residing body, such as braces, gums, fillings, cavities, piercings, etc.) to fluoresce at a different wavelength to plaque in order to increase the visibility of plaque in the oral cavity. Advantageously, such embodiments facilitate the detection (and subsequent removal) of plaque that is present in the oral cavity (e.g., by facilitating the determination of a brushing pattern or configuration for the subject in the detected location of the plaque).

[0031] Similarly, in the first and second aspects, in the first mode, an emission peak of radiation emitted from the EM radiation source arrangement activated in the first mode may have a wavelength at or around 405 nm. Advantageously, such embodiments enable the improved detection of plaque, as the emitted radiation is capable of inducing QLF of tooth enamel and plaque in an oral cavity to increase the visibility of any plaque in the oral cavity (whilst still remaining safe for the subject).

[0032] In a third aspect, there is provided an apparatus for controlling operation of an IOD that is operable in an oral cavity of a subject. The apparatus comprises one or more processors configured to cause the apparatus to : analyze first images obtained by an imaging device in the IOD to determine whether one or more teeth are present in one or more of the first images; and generate one or more first signals if the one or more teeth are determined to be present in one or more of the first images. The one or more first signals are configured to cause activation of a first mode of an electromagnetic radiation source arrangement in the IOD. In the first mode, the EM radiation source arrangement is capable of causing photobiological damage to the subject. The third aspect provides an example implementation of the methods described earlier with reference to the first aspect.

[0033] In a fourth aspect, there is provided an IOD that is operable in an oral cavity of a subject. The IOD comprises one or more processors configured to cause the IOD to obtain first images using an imaging device in the IOD; and transmit the first images to a processing device external to the IOD. The one or more processors are further configured to cause the IOD to receive, from the processing device, one or more first signals indicative of one or more teeth being present in one or more of the first images transmitted to the processing device. The one or more processors are further configured to cause the IOD to, responsive to receiving the one or more first signals, cause activation of a first mode of an electromagnetic, EM, radiation source in the IOD. In the first mode, the EM radiation source is capable of causing photobiological damage to the subject. The fourth aspect provides an example implementation of the methods described earlier with reference to the second aspect.

[0034] In a fifth aspect, there is provided a system comprising the apparatus as previously described and the IOD as previously described, wherein the apparatus is operable to communicate with2025PF00031

[0035] 5

[0036] the IOD. The fifth aspect provides an example implementation of the apparatus and IOD described earlier with reference to the third and fourth aspects, respectively.

[0037] According to a sixth aspect, there is provided a computer program product comprising a computer readable medium. The computer readable medium has a computer readable code embodied therein. The computer readable code is configured such that, on execution by a suitable computer or processor, the computer or processor is caused to perform the method described earlier.

[0038] These and other aspects will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

[0039] BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Exemplary embodiments will now be described, by way of example only, with reference to the following drawings, in which:

[0041] Fig. 1 is a flow chart illustrating a method according to an embodiment;

[0042] Figs. 2a and 2b are images of a set of teeth in an oral cavity;

[0043] Fig. 3 shows a set of images that are input into an ML model to obtain a set out of output illustrations;

[0044] Fig. 4a is a schematic diagram of a system acccording to an embodiment;

[0045] Fig. 4b is a schematic diagram of an IOD acccording to an embodiment;

[0046] Fig. 5 is a flow chart illustrating a method according to an embodiment;

[0047] Fig. 6 is a block diagram illustrating an example apparatus according to embodiments of the disclosure; and

[0048] Fig. 7 is a block diagram illustrating an example processor according to embodiments of the disclosure.

[0049] DETAILED DESCRIPTION OF EMBODIMENTS

[0050] There are provided herein techniques for controlling operation of an IOD that is operable in an oral cavity of a subject.

[0051] For the purposes of the following disclosure, an IOD comprises an imaging device and an EM radiation source arrangement. The EM radiation source arrangement is operable in a first mode. An IOS may be considered an example of an IOD.

[0052] For the purposes of the present disclosure, the term “first mode” may be used to refer to an operating mode of the EM radiation source arrangement in which the EM radiation source arrangement is capable of causing photobiological damage to a subject. For example, when operable in the first mode, the EM radiation source arrangement may be operable to emit radiation with a wavelength equal to or shorter than 405 nm, such as near-ultraviolet (UV) radiation. In particular, an emission peak of the radiation emitted from the EM radiation source arrangement activated in the first mode may have a2025PF00031

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[0054] wavelength at or around 405 nm. Such radiation may be considered safe for irradiating an oral cavity of a subject but a potential hazard to eye and skin tissue.

[0055] As used herein, “photobiological damage” includes any type of optical damage and / or thermal damage caused by light to soft tissue, particularly skin tissue or eye tissue (e.g. the retina or cornea).

[0056] As such, the EM radiation source arrangement may comprise a source of near-UV radiation. The near-UV radiation source may be turned on when the EM radiation source arrangement is operating in the first mode and turned off when the EM radiation source arrangement is operating in the second mode (or when the first mode is deactivated). For example, the EM radiation source arrangement may comprise a near-UV light-emitting diode (LED), a near-UV laser, a near-UV lamp, or any other device operable to emit near-UV radiation. For example, the near-UV LED may be a blue LED that emits EM radiation having a peak wavelength of around 405 nm.

[0057] If the first mode of the EM radiation source arrangement is activated, the IOD may be referred to herein as operating “in an unsafe light mode” and / or “with unsafe light conditions”. That is, radiation emitted from the EM radiation source arrangement operating in the first mode may cause harm to the human body, e.g. to the eyes, if the EM radiation source arrangement is held in close proximity to soft tissue of the human body for extended periods of time (e.g., 20 minutes) and / or with the wrong settings and / or is otherwise misused by the user. However, it should be appreciated that such radiation is considered safe when the IOD is operated in an oral cavity, particularly for the purpose of irradiating tooth enamel.

[0058] The EM radiation source arrangement may be considered “turned off” when the first mode is deactivated.

[0059] The EM radiation source arrangement may optionally be operable in a second mode. For the purposes of the present disclosure, the term “second mode” may be used to refer to an operating mode of the EM radiation source arrangement in which the EM radiation source arrangement is capable of causing no or minimal photobiological damage to a subject. For example, when operable in the second mode, the EM radiation source arrangement may be operable to emit radiation having a wavelength between 405 nm and 700 nm. For example, radiation emitted from the EM radiation source arrangement activated in the second mode may be visible light. The emitted radiation may comprise a combination of different wavelength radiation, wherein the wavelengths are between 405 to 700 nm. For example, whilst activated in the second mode, the EM radiation source arrangement may emit white light.

[0060] As such, the EM radiation source arrangement may further comprise a source of visible light. The source of visible light may be turned on when the EM radiation source arrangement is operating in the second mode and may or may not be turned off when the EM radiation source arrangement is operating in the first mode. The visible light may be turned off when the second mode is deactivated. For example, the EM radiation source arrangement may comprise a visible light LED, a visible light laser, a visible light lamp, or any other device operable to emit visible light radiation.2025PF00031

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[0062] It will be appreciated that the source of near-UV light may be the same or a different physical entity to the source of visible light.

[0063] Whilst activated in the second mode, the EM radiation source arrangement may emit the visible light with a brightness that is safe for the human eye to be exposed to for extended periods of time, whilst also being suitable for illuminating surfaces that are to be imaged by a camera sensitive to visible light.

[0064] If the second mode of the EM radiation source arrangement is activated, the IOD may be referred to herein as operating “in a safe light mode” and / or “with safe light conditions”. That is, radiation emitted from the EM radiation source arrangement operating in the second mode causes minimal or no photobiological harm to the human body, e.g. to the eyes, if the EM radiation source arrangement is held in close proximity to soft tissue of the human body for extended periods of time.

[0065] The EM radiation source arrangement may be considered “turned off’ when both the first mode and the second mode are deactivated. However, it should also be appreciated that, when operating in the second mode, the EM radiation source arrangement may be operable to emit no radiation. In this case, the EM radiation source arrangement may be considered “turned off’ when operating in the second mode.

[0066] The EM radiation source arrangement may operate in the first mode and the second mode simultaneously, or in neither mode (e.g., when the IOD is turned off).

[0067] Fig. 1 illustrates a method 100 of controlling operation of an IOD that is operable in an oral cavity of a subject according to an embodiment. More specifically, Fig. 1 illustrates a method 100 of operating an apparatus, such as the apparatus 600 described later with reference to Fig. 6, for controlling operation of an IOD that is operable in an oral cavity of a subject. As discussed in more detail below, the apparatus may be a processor of (and / or embedded in) the IOD, or the apparatus may be an (external) processing device such as a cloud computing network, a wireless device (e.g., a smartphone), a computing device (e.g., a computer, a laptop, etc.), or any other suitable processing device that is operable to be communicatively coupled to the IOD.

[0068] The method 100 illustrated in Fig. 1 is a computer-implemented method. For example, the method 100 may be implemented by an application or software installed on the apparatus 600. As described later with reference to Fig. 6, the apparatus 600 comprises one or more processors 602. The method 100 illustrated in Fig. 1 can generally be performed by or under the control of the one or more processors 602 of the apparatus 600 described later with reference to Fig. 6, such as a processor 700 described later with reference to Fig. 7.

[0069] With reference to Fig. 1, at block 102, the method comprises analyzing first images obtained by an imaging device in the IOD to determine whether one or more teeth are present in one or more of the first images. Block 102 may be performed by a processor, such as an analyzing processor, of the apparatus 600.2025PF00031

[0070] 8

[0071] At block 104 of Fig. 1, the method comprises generating one or more first signals if the one or more teeth are determined to be present in one or more of the first images. The one or more first signals are configured to cause activation of a first mode of an EM radiation source arrangement in the IOD. Whilst operating in the first mode, the EM radiation source arrangement is capable of causing photobiological damage to the subject. Block 104 may be performed by a processor, such as a signal generating processor, of the apparatus 600.

[0072] The method of Fig. 1 is now discussed in more detail.

[0073] As previously discussed, the method at block 102 comprises analyzing first images obtained by an imaging device in the IOD to determine whether one or more teeth are present (e.g., detectable by an apparatus implementing the method 100) in one or more of the first images. The imaging device may comprise an image sensor that is sensitive to visible light. The imaging device may be a camera. An example camera is an “RGB camera”. An RGB camera is a camera that uses a Color Array Filter (CFA) with a standard Bayer pattern. The CFA is sensitive to the primary colors of visible light: red, green, and blue. However, the imaging device may be any suitable device that can be embedded in an IOD and can capture images of an oral cavity.

[0074] The imaging device may point in (generally) the direction in which radiation is emitted from the EM radiation source arrangement when the EM radiation source arrangement is activated in the first mode (and / or in the second mode). For example, the EM radiation source arrangement may be configured such that it irradiates, when activated in the first mode (and / or, in the second mode), an area that (at least partially) overlaps with a field of view of the imaging device. For example, the imaging device may capture images of an area which would be irradiated by the EM radiation source arrangement, if the EM radiation source arrangement were activated in the first mode (and / or, in the second mode).

[0075] The method 100 may comprise acquiring the first images prior to block 102. As discussed in further detail below, if the method is performed by the IOD, acquiring the first images may comprise using the imaging device to capture the first images. If the method is performed by a processing device that is external to the IOD, acquiring the first images may comprise receiving the first images, directly or indirectly, from the IOD (e.g., via a communication channel established between the IOD and the processing device). In this case, acquiring the first images may correspond to block 504 of the method discussed below with reference to Fig. 5.

[0076] The first images may be acquired over an extended time period (e.g., periodically). For example, the first images may form (at least a part of a) video stream. One of the first images may be acquired and / or analysed before another of the first images is acquired and / or analysed. In this way, the method 100 may enable real-time processing of a video stream obtained using the imaging device of the IOD.

[0077] The first images may have been captured by the IOD, using the imaging device, whilst the subject is illuminated (i.e., irradiated) by low-intensity and / or low brightness visible light, such as white light. This illumination of the subject may be achieved via activation of the second mode of the EM2025PF00031

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[0079] radiation source arrangement. The second mode of the EM radiation source arrangement may be activated using one or more third signals generated by the apparatus 600 (and, optionally, output to the IOD). The one or more third signals may be generated responsive to the reception of an indication that a user wishes to activate the second mode and / or acquire the first images.

[0080] If, as a result of block 102, one or more teeth are determined to be present (i.e., are detected) in one or more of the first images, this may indicate that the imaging device of the IOD was pointing at teeth whilst the first images were captured by the imaging device. Based on this indication, it may be determined, assumed, and / or derived that the IOD is located in an oral cavity. That is, as a result of block 102, it may be determined that a user has safely located or positioned the IOD for the purposes of irradiating teeth using the EM radiation source arrangement operating in the first mode (or first “modality”). Assuming that the IOD has not moved significantly between a time at which the first images were captured and a time at which teeth were determined to be present in one or more of the first images, the method may comprise determining that it is safe to activate, within a given period of time after the determination has been made (e.g., within the next 4s, but preferably within the next Is), the first mode of the EM radiation source arrangement.

[0081] Thus, at block 104 of Fig. 1, the method comprises generating one or more first signals if the one or more teeth are determined to be present in one or more of the first images. For example, the one or more first signals generated at block 104 may be acknowledgements (ACKs) of detected teeth.

[0082] The one or more first signals are configured to cause activation of the first mode of the EM radiation source arrangement in the IOD. The term “causing activation” should be considered to encompass both initiating activation of the first mode and maintaining activation of the first mode. Whilst operating in the first mode, the EM radiation source arrangement is capable of causing photobiological damage to the subject. Details of how the one or more first signals may be used to cause such activation are provided below with reference to Figs. 4a and 4b.

[0083] Thus, the one or more first signals are advantageous as they may be used to allow the IOD to switch to an "unsafe" modality (i.e., the first mode) only when photobiologic damage to the subject is unlikely (i.e., when the IOD is located in an oral cavity).

[0084] The one or more first signals may allow the first mode of the EM radiation source arrangement to be activated until the IOD is otherwise indicated, and / or until a given period of time has elapsed after their generation. For example, the one or more first signals may be configured to indicate to the IOD that it can begin or keep on using the first mode of the EM radiation source arrangement for the next n seconds, n may be between 0.25s and 4s, and is preferably between 0.5s and 1.0s. This indication may be explicit or implicit. For example, the IOD may be configured to begin or keep on using the first mode of the EM radiation source arrangement for the next n seconds after the one of the one or more first signals are generated and / or received by the IOD. n may be defined in a configuration of the IOD.2025PF00031

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[0086] If teeth are not present or detected in one or more of the first images, the method 100 may comprise performing an action. The action may comprises one or more of: preventing activation of the first mode; not causing activation of the first mode; deactivating the first mode; deactivating the EM radiation source arrangement; and causing activation of a second mode of the EM radiation source arrangement.

[0087] In the second mode, the EM radiation source arrangement is not capable of causing photobiological damage to the subject. That is, the IOD may be caused to (e.g., automatically) revert to “safe light conditions” (e.g., by activating the second mode and / or by deactivating the first mode). This may be achieved via the method of Fig. 1 by either refraining from generating first signals, and / or generating second signals that explicitly indicate that teeth are not detected in the first images. For example, the above discussed action may be performed by one or more of: preventing generation of the one or more first signals; not generating the one or more first signals; and generating one or more second signals configured to prevent activation of the first mode and / or to cause activation of the second mode.

[0088] The one or more second signals may be non-acknowledgements (NACKs) of detected teeth. For example, the one or more second signals may prevent the first mode of the EM radiation source arrangement from being activated until otherwise indicated (e.g., by receiving one or more first signals), and / or until a given period of time has elapsed since the generation and / or reception of the second signals by the IOD. The one or more second signals may cause the EM radiation source arrangement to deactivate the first mode of the EM radiation source arrangement and / or initiate or continue operating in the second mode of the EM radiation source arrangement. Thus, the one or more second signals are advantageous as they may be used as an explicit indication configured to prevent the IOD switching to or otherwise operating in an "unsafe" modality (i.e., the first mode) when photobiologic damage to the subject is likely.

[0089] It will be appreciated that activation of the first mode of the EM radiation source arrangement may be beneficial as it enables teeth to be irradiated by radiation generated by the EM radiation source arrangement. Any plaque in an oral cavity (e.g., on the surface of teeth) may have increased visibility and can therefore be identified for the removal purposes.

[0090] For example, whilst activated in the first mode, the EM radiation source arrangement may be capable of causing tooth enamel (or any other plaque-residing body, such as braces, gums, fillings, cavities, piercings, etc.) to fluoresce at a different wavelength to plaque in order to increase visibility of plaque present in the oral cavity. That is, whilst activated in the first mode, the EM radiation source arrangement may be capable of inducing QLF of tooth enamel (or any other plaque-residing body, such as braces, gums, fillings, cavities, piercings, etc.) and / or plaque. For example, when irradiated by radiation emitted from the EM radiation source arrangement operating in the first mode, any plaque present in the oral cavity may appear red and / or orange (as the enamel may fluoresce whilst emitting radiation comprising visible light having a (e.g. peak) wavelength between 585 nm and 750 nm), whilst tooth2025PF00031

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[0092] enamel may appear green (as the enamel may fluoresce whilst emitting radiation comprising visible light having a (e.g. peak) wavelength between 490 nm and 570 nm).

[0093] As such, the surface of a tooth irradiated by the EM radiation source arrangement activated in the first mode may be seen, to the human eye and / or to cameras sensitive to visible light, to be made up of regions of different colours. This is illustrated in Figs. 2a and 2b. Fig. 2a is an image of a set of teeth 202 in an oral cavity captured using a camera that is sensitive to visible light. The set of teeth 202 in Fig. 2a is irradiated (only) using the EM radiation source arrangement whilst operating in the second mode, meaning enamel of the set of teeth 202 is not undergoing QFL and any plaque on the set of teeth 202 is barely visible to the human eye and / or the camera. Fig. 2b is an image of the same set of teeth 202 that is captured using the same camera. In contrast to Fig. 2a, the set of teeth 202 in Fig. 2b is irradiated by the EM radiation source arrangement whilst activated in the first mode, meaning the tooth enamel and plaque on the teeth are undergoing QFL at different wavelengths. As such, the plaque is visible to the human eye and / or the camera. In particular, the regions 204, and 206, of the set of teeth 202 will be seen, to the human eye, to have a green colour, caused by tooth enamel in these regions fluorescing at a first wavelength. In contrast, the regions 210 and 212 will be seen, to the human eye, to have a red or orange colour, caused by plaque on the tooth enamel in these regions fluorescing at a longer, second wavelength.

[0094] Therefore, returning to the method of Fig. 1, whilst the first mode of the EM radiation source arrangement is activated, the IOD may be configured to obtain (using the imaging device) additional images of the oral cavity. As will be appreciated from Fig. 2b, the additional images would record the presence of any plaque in an oral cavity of the subject. Analysis of the additional images may then be performed to determine the location of plaque in the oral cavity. This analysis may be performed for the purpose of determining a brushing configuration for an electric toothbrush based on the location of the plaque and / or for mapping the locations of tooth enamel in the oral cavity. Such analysis may be performed by an image processor of the apparatus 600.

[0095] Embodiments for analyzing the first images are now discussed.

[0096] As an example, at block 102, analysing the first images may comprise using an ML model trained to identify teeth in image data input into the ML model. For the purposes of the present disclosure, the term “ML model” encompasses within its scope the following concepts: ML algorithms, comprising processes or instructions through which data may be used in a training process to generate a model artefact for performing a given task, or for representing a real world process or system; the model artefact that is created by such a training process, and which comprises the computational architecture that performs the task; and the process performed by the model artefact in order to complete the task. The terms ML model, Artificial Intelligence (Al) model, AI / ML (AIML) model, ML algorithm, and Al algorithm may be used interchangeably herein.

[0097] For example, block 102 may comprise an ML algorithm being applied to the first images. The ML algorithm may be trained to predict the presence of teeth in the first images input into the2025PF00031

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[0099] algorithm. The ML algorithm may be a neural network. The ML algorithm may have been trained using deep learning techniques.

[0100] An example of the ML algorithm is an AIML model operable to implement instance segmentation and / or image classification. The AIML model may be trained on collected and, optionally, annotated data of teeth. The annotation may be performed using any suitable framework, such as Amazon Sagemaker, Roboflow or Labelbox. The model may be trained in any suitable framework, such as PyTorch or TensorFlow. The AIML model may be trained on, for example, around 1000 images per image modality, although much higher or lower numbers of images may be used.

[0101] Fig. 3 shows example inputs and outputs of the AIML model. The inputs of the AIML model, shown in the left hand side column, are input images captured by an imaging device of the IOD. First input images 302a is of teeth illuminated (i.e., irradiated) using white light, whilst second input image 304a is of teeth irradiated using radiation with a peak wavelength of around 405nm.

[0102] The outputs of the AIML model, shown in the right hand side of Fig. 3, are output illustrations of predicted locations of teeth within the input images. That is, the AIML model predicts whether pixels included in an input image are considered to contain image data representing tooth enamel (“teeth pixels”). If a pixel is predicted to contain said image data, a corresponding pixel in the output illustration is shown as white. If a pixel is not predicted to contain said image data, a corresponding pixel in the output illustration is shown as black. That is, the AIML model may generate a predication mask for the input images, wherein the prediction mask identifies the predicted location and / or presence of teeth in the input images.

[0103] Therefore, first output illustration 302b shows white regions corresponding to the location of teeth in the first input image 302a, and black regions where no teeth are detected to be present in the first input image 302a. Second output illustration 304b shows white regions corresponding to the location of teeth in the second input image 304a, and black regions where no teeth are detected to be present in the second input image 304a. In the event that an input image is found to not contain teeth at all, the output illustration would be completely black.

[0104] The output of the AIML model may be used to determine whether teeth, gums and / or other oral features are present in an input image. As an example, this determination may comprise determining, based on the output illustration of the AIML model, whether a sufficient number of teeth pixels are detected in the input / output image (e.g., the number of teeth pixels in the input / output image is equal to or larger than a threshold number of teeth pixels). The determination may be based on a ratio of teeth pixels to “non-teeth pixels” in the input / output image, wherein the non-teeth pixels are pixels in the input / output image that are not considered to contain image data representing tooth enamel. This ratio may be referred to herein as a “pixel positive ratio”.

[0105] If a sufficient number of teeth pixels are determined to be present in an input / output image (e.g., the pixel positive ratio for the input / output image meets a threshold), it may be determined that there are teeth present in the input / output image and / or that the IOD was in an oral cavity (or at least2025PF00031

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[0107] pointing at teeth) when the input image was captured. Conversely, if a sufficient number of teeth pixels are not detected in the input / output image (e.g., the pixel positive ratio for the input image does not meet a threshold), it may be determined that there are not teeth in the input / output image and / or that the IOD was not in an oral cavity (or at least not pointing at teeth) when the input image was captured.

[0108] For example, the threshold may be 0.25. Based on the output illustration 302b, it can be determined that the pixel positive ratio for the first input image 302a is 0.40. As such, teeth are predicted to be present in the first input image 302a based on the threshold. Based on the second output illustration 304b, it can be determined that the pixel positive ratio for the second input image 304a is 0.59. As such, teeth are predicted to be present in the second input image based 304a. on the threshold. For an output illustration that is completely black, the pixel positive ratio for the corresponding input image would be 0.00. As such, teeth would not be predicted to be present in that input image.

[0109] To avoid false positives (i.e., determinations that teeth are present in the first images when they are not), the threshold of the AIML model may be adjusted such that a high percentage of teeth pixels (e.g., > 40%) are required in an input image for the input image to be determined to contain teeth. This may increase the number of determined false negatives (i.e., determinations that teeth are not present in the first images when they are) and scanning time, but safety may also be increased. That is, it reduces risk that the EM radiation source arrangement will be activated when the IOD is located outside an oral cavity.

[0110] The determination of whether teeth are present in the input images may be performed by the AIML model (which may be incorporated in or accessible to the apparatus 600), and / or a processor of the apparatus 600 that receives an output of the AIML model.

[0111] The skilled person will appreciate that other techniques, algorithms, and / or Al models may be used to determine whether teeth are present in first images obtained by an imaging device in the IOD. For example, rather than using a teeth segmentation algorithm and counting teeth pixels in an input / output image, the AIML model may implement a classifier trained to sort input data into predefined categories (“teeth present in the input data” and “teeth not present in the input data”). The likelihood of the classifier outputting false positives and / or false negatives can be tailored by selecting an appropriate probability threshold for the classifier.

[0112] The analysis at block 102 may use a classical algorithm configured to identify teeth in image data to which the classical algorithm is applied. As an example, the classical algorithm may comprise applying computer vision techniques to the first images that are operable to identify teeth in image data to which the computer vision techniques are applied.

[0113] The method 100 and / or the analysis performed at block 102 may further comprise the use of one or more hysteresis techniques. For example, at block 102, the first images may be analyzed using one or more hysteresis techniques. The one or more hysteresis techniques may be configured to incorporate analysis of second images previously obtained using the imaging device to inform the analysis / processing of the first images. For example, the analysis performed at block 102 may look at a2025PF00031

[0114] 14

[0115] series of frames obtained from the imaging device of the IOD to make decision as to whether the one or more first signals should be generated.

[0116] For example, the hysteresis techniques may analyse a plurality of first images obtained using the imaging device of the IOD, and may make a determination of whether a threshold number of the first images comprise teeth. If the threshold number is not met, the one or more first signals may not be generated. If the threshold number is met, the one or more first signals may be generated. This helps ensure stable generation of the one or more first signals.

[0117] For example, the hysteresis techniques may comprise the implementation of a state machine. A first (default) state of the state machine may be that no teeth are considered detected in images obtained using the imaging device of the IOD. When the state machine is in the first state, no first signals may be generated. It may take a series of determinations that teeth are present in a plurality of the first images (e.g., consecutive first images) to switch the state machine to a second state in which teeth are considered detected in images obtained using the imaging device of the IOD. When the state machine is in the second state, the one or more first signals may be generated.

[0118] Analysing or processing the first images using the one or more hysteresis techniques enables a more stable generation of first and / or second signals and reduces the likelihood of false positives. This is because the hysteresis techniques enable the output of the analysis at block 102 to depend on a current images and past images obtained using the imaging device of the IOD. This helps prevent the IOD from rapidly switching between safe and hazardous light settings due to small changes or noise in the first images. By using hysteresis techniques, the IOD will only switch to a hazardous light setting if there is a significant and sustained change in the first images (i.e., the appearance and presence of teeth in the first images). This creates a buffer zone, making the IOD more reliable and safer.

[0119] The analysis performed at block 102 may further comprise analyzing the first images using image processing, such as by applying morphological operations. The morphological operations may be operable to identify teeth in image data to which the morphological operations are applied. For example, the morphological operations may determine (and, optionally, modify) structural elements of the teeth as captured in the first images. The structural elements may be one or more of a size, a shape, an area, etc. of the teeth as captured in the first images. The determined structural elements may be compared to known, typical, and / or default structural elements of teeth of a generic user (e.g., a typical tooth size, shape, area, etc). This comparison may be used to facilitate the determination of whether teeth are present in the first images, such that the determination results in a reduced number of false positives.

[0120] The morphological operations may also enable one or more of advantageous features of the apparatus 600. For example, a detected tooth within the first images may be compared with images of a pre-scanned tooth of a subject. The images of the pre-scanned tooth may have been obtained during a calibration scan performed for the subject and stored in a database. Any structural element of the detected tooth (e.g., the size, shape, area, etc.) may be compared with corresponding structural elements of the prescanned tooth. This comparison can be performed using ML or Al models / algorithms. If the detected2025PF00031

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[0122] tooth and pre-scanned tooth are determined, based on this comparison, to meet one or more similarity criteria, the subject of the first images analysed at block 102 may be identified. These first images may then be stored (e.g., in a database that may be internal or external to the apparatus and / or the IOD) with an association to an identifier of the subject.

[0123] If the subject is known (e.g., from metadata associated with the subject) to be below a certain age, the method may comprise preventing use of (or not generating) the one or more first signals for activating the first mode of the EM radiation source arrangement. That is, the method of Fig. 1 may comprise a child-lock mechanism which prevents the activation of the first mode of the EM radiation source arrangement in the oral cavity of the subject (a child), even if teeth are detected in the first images.

[0124] The method of Fig. 1 may additionally or alternatively implement this child lock mechanism based on a comparison of the detected tooth to example teeth of adults and / or teeth of children. In particular, any structural element of a detected tooth (e.g., the size, shape, area, etc.) may be compared with corresponding structural elements of example child and / or adult teeth. If the detected tooth and example adult teeth are determined, based on the comparison, to meet one or more similarity criteria, the method may proceed without implementing the child lock mechanism. If the detected tooth and example children teeth are determined, based on the comparison, to meet one or more similarity criteria, the method may implement the child lock mechanism.

[0125] It will be appreciated that one or more of the method steps discussed in relation to block 102 and / or block 104 may be performed responsive to the reception of an activation indication (e.g., responsive to the apparatus 600 receiving an activation indication). In the context of the present disclosure, an activation indication refers to an indication (e.g., a signal) that indicates that a user of the IOD wishes to, intends to, or is requesting to cause activation of a first mode of the EM radiation source arrangement. For example, this activation indication may be generated by a user of the IOD pressing a button, a switch, or any other suitable actuator.

[0126] As previously mentioned, the method of Fig.1 may be performed by a processing device that is external to the IOD. For example, the apparatus 600 may be one or more of a cloud computing network, a wireless device, a computing device, and any other suitable processing device. In such embodiments, the method of Fig. 1 may be performed by one or more processors of the cloud computing network, wireless device, computing device, and any other suitable processing device.

[0127] Such embodiments are illustrated by the schematic diagram of Fig. 4a. Fig. 4a illustrates a system 400 comprising a processing device 402 and an IOD 404, wherein the processing device 402 and the IOD 404 are physically distinct (i.e., separate logical entities). The processing device 402 is communicatively coupled to the IOD 404 via an established communication channel 406. The communication channel 406 may be operable to transmit communication between the processing device 402 and IOD 404 via radio communication, Bluetooth®, WiFi®, a wired connection, and / or any other suitable communication standard or technique. The communication may comprise first images obtained by the imaging device of the IOD and / or signals generated by the processing device.2025PF00031

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[0129] For example, the method of Fig. 1 may comprising acquiring, from the IOD, the first images analyzed at block 102. This step may comprise receiving the first images via the established communication channel 406. The first images may be received periodically and / or as part of a video stream.

[0130] The method of Fig. 1 may further comprise outputting the one or more first signals to the IOD. The one or more first signals may be output via the established communication channel 406.

[0131] Responsive to receiving the one or more first signals, the IOD may activate the first mode of the EM radiation source arrangement. For example, the IOD may use the one or more first signals to activate the first mode of the EM radiation source arrangement. For example, the one or more first signals may be output periodically to the IOD, such that the device receives periodic indications to cause the activation of the first mode of the EM radiation source arrangement. The first mode of the EM radiation source arrangement may (e.g., only) be activated if the one or more first signals are received by the IOD.

[0132] For example, whilst teeth are detected in the first images acquired from the IOD, the apparatus may output periodic ACK signals to the IOD at rate between 0.25s and 4s (preferably at a rate between 0.5 s and Is). As long as the IOD receives the ACK signals, the first mode of the EM radiation source arrangement may be and / or remain activated, at least for a given period of time after each ACK signal is received or until a NACK is received.

[0133] If teeth are not determined to present in the first images, the method may comprise preventing the output of signals to the IOD that are configured to cause activation of the first mode (i.e., first signals). Similarly, if teeth are not determined to present in the first images, the method may comprise not outputting signals to the IOD that are configured to cause activation of the first mode (i.e., first signals).

[0134] It will be appreciated that the IOD may prevent activation of the first mode of the EM radiation source arrangement if the one or more first signals are not received by the IOD (e.g., due to no teeth being detected in the first images analyzed at block 104, and / or due to a failure of the communication channel established between the apparatus 600 and the IOD). In other words, the IOD may exist in a default state in which it is prevented from activating the first mode of the EM radiation source arrangement until one or more first signals are received.

[0135] Furthermore, the method of Fig. 1 may further comprise outputting the one or more second signals to the IOD. The one or more second signals may be output via the established communication channel 406. The IOD may prevent activation of the first mode (and, optionally, activate the second mode) responsive to the reception of the one or more second signals. For example, the one or more second signals may be output periodically to the IOD, such that the device receives periodic indications to prevent activation of the first mode (and, optionally, to activate the second mode).

[0136] For example, whilst teeth are not detected in the first images acquired from the IOD, the apparatus may output periodic NACK signals to the IOD at rate between 0.25s and 4s (preferably at a rate between 0.5s and Is). As long as the IOD receives the NACK signals, the first mode may be prevented2025PF00031

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[0138] from activation (e.g., for a given period of time after each NACK signal is received, or until an ACK is received) (and, optionally, the second mode may be activated).

[0139] Output of the one or more first signals and / or the one or more second signals to the IOD may be performed by a transmitting device of the apparatus 600.

[0140] The method may further comprise acquiring, from the IOD, additional images of the oral cavity obtained by the IOD using the imaging device whilst the first mode of the EM radiation source arrangement is activated. This step may be performed by a receiving device of the apparatus 600. The additional images may be received via the established communication channel 406. The additional images may be analyzed to determine the location of plaque in the oral cavity, as previously discussed, by an image processor of the apparatus 600.

[0141] Alternatively, the apparatus may be the IOD. That is, the method of Fig. 1 may be performed by one or more processors of the IOD. Such embodiments are illustrated by the schematic diagram of Fig. 4b. Fig. 4b illustrates an IOD 408 comprising a controller 410, wherein the IOD 408 is operable to perform the method of Fig. 1 (e.g., via the controller 410). The controller 410 is operable to control the IOD 408, particularly whether the EM radiation source arrangement of the IOD is operating in the first mode (and, optionally, the second mode). The controller 410 may be incorporated or embedded in the IOD 408.

[0142] Thus, instead of relying on an external processing device to perform the method at blocks 102 and 104, the functionality of these blocks can be performed by the IOD 408 itself (e.g., using the controller 410), particularly if the controller 410 (e.g., a microcontroller) embedded in the IOD 408 is powerful enough to perform the analysis of block 102 with low latency. For example, if an AIML model is used for block 102 by one or more processors of the IOD 408, it may be simplified (e.g. by quantization, pruning of the weights, or model distillation) in comparison to an AIML model that might otherwise be used to perform teeth detection and / or image classification by an external processing device. Whilst a simplified AIML model may have increased chances of outputting false positives, it would enable the IOD 408 to be used without relying on a communication channel established between the IOD 408 and a communication device that may otherwise perform the analysis at block 102. This may be more convenient for the user and avoid issues that may arise if such communication channel fails.

[0143] In such embodiments, the method 100 may further comprise the IOD 408 activating the first mode of the EM radiation source arrangement responsive to the generation of the one or more first signals (e.g., by the controller 410). That is, the generation of the one or more first signals may cause activation of the first mode of the EM radiation source arrangement. For example, the one or more first signals may be used to activate the first mode. The one or more first signals may be periodically generated, such that the IOD 408 receives (e.g., from the controller 408) periodic indications to cause the activation of the first mode of the EM radiation source arrangement. The first mode of the EM radiation source arrangement may be (e.g., only) activated if the one or more first signals are generated by the IOD 408 (e.g., by the controller 410) and / or the first mode of the EM radiation source arrangement may be2025PF00031

[0144] 18

[0145] prevented from activation if the one or more first signals are not generated by the IOD 408 (e.g., by the controller 410).

[0146] For example, whilst teeth are detected in the first images acquired from the IOD 408, the IOD 408 may generate periodic ACK signals at rate between 0.25s and 4s (preferably at a rate between 0.5s and Is). As long as the ACK signals are generated, the EM radiation source arrangement may be and / or remain activated in the first mode (e.g., for a given period of time after each ACK signal is generated, or until a NACK is generated).

[0147] It will be appreciated that the apparatus may prevent activation of (or not activate) the first mode of the EM radiation source arrangement if the one or more first signals are not generated by the IOD 408 (e.g., due to no teeth being detected in the first images analyzed at block 104).

[0148] Furthermore, the method 100 may further comprise the IOD 408 preventing activation of (or not activating) the first mode of the EM radiation source arrangement responsive to the generation of the one or more second signals. That is, the generation of the one or more second signals may prevent activation of the first mode of the EM radiation source arrangement. The one or more second signals may be generated periodically, such that the IOD 408 receives periodic indications to prevent activation of the first mode of the EM radiation source arrangement. The first mode of the EM radiation source arrangement may be prevented from activation if the one or more second signals are generated by the IOD 408.

[0149] For example, whilst teeth are not detected in the first images acquired from the IOD 408, the apparatus may generate periodic NACK signals at rate between 0.25s and 4s (preferably at a rate between 0.5 s and Is). As long as the apparatus generates the NACK signals, the first mode of the EM radiation source arrangement may be prevented from activation or not activated (e.g., for a given period of time after each NACK signal is received, or until an ACK is received).

[0150] Activation of the first mode of the EM radiation source arrangement be performed by a processor of the IOD 408 (e.g., the controller 410), particularly a processor that is communicatively coupled to the EM radiation source arrangement. Similarly, prevention of activation of the first mode of the EM radiation source arrangement be performed by a processor of the IOD 408 (e.g., the controller 410), particularly a processor that is communicatively coupled to the EM radiation source arrangement.

[0151] The method may further comprise the IOD 408 acquiring, whilst the first mode of the EM radiation source arrangement is activated, the previously discussed additional images of the oral cavity. This step may be performed by the imaging device of the IOD 408. The method may further comprise the IOD 408 analyzing the additional images to determine the location of plaque and / or tooth enamel within the oral cavity. This analysis may be performed by an image processor of the IOD 408. Additionally or alternatively, the additional images may be output to an external processing device that is operable to perform at least part of the analysis.

[0152] Fig. 5 illustrates a method 500 performed by an IOD that is that is operable in an oral cavity of a subject according to an embodiment. The IOD comprises an imaging device and an EM2025PF00031

[0153] 19

[0154] radiation source arrangement. The imaging device and EM radiation source arrangement may correspond to the imaging device and EM radiation source arrangement discussed above in reference to Fig. 1. As such, the skilled person is directed to the discussion of Fig. 1 for further detail regarding these components.

[0155] More specifically, Fig. 5 illustrates a method 500 of operating an IOD, which may be an example of the apparatus 600 described later with reference to Fig. 6 or the IOD 404 described earlier with reference to Fig. 4. As described later with reference to Fig. 7, the apparatus 600 comprises one or more processors 602. The method 500 illustrated in Fig. 5 can generally be performed by or under the control of the one or more processors 602 of the apparatus 600 described later with reference to Fig. 6, such as a processor 700 described later with reference to Fig. 7.

[0156] With reference to Fig. 5, at block 502, the method comprises obtaining first images using an imaging device in the IOD. The first images may be obtained, using the imaging device, whilst the first mode of the EM radiation source arrangement is inactivated and / or whilst a second mode of the EM radiation source arrangement is activated. That is, the first images may be obtained, using the imaging device, whilst the IOD is operating with safe light conditions. For example, the first images may be obtained whilst the IOD is outputting visible light (e.g., white light) at a relatively low intensity. The visible light may be emitted by the EM radiation source arrangement operating in the second mode.

[0157] Block 502 may be performed by a receiving device of the IOD (which may obtain the first images from the imaging device) and / or by the imaging device itself.

[0158] At block 504 of Fig. 5, the method comprises transmitting the first images to a processing device (e.g. processing device 402) external to the IOD. The processing device may be an apparatus implementing the method of Fig. 1. For example, the processing device may be one of a wireless device (e.g., a smartphone), a cloud computing network, a computing device, and any other suitable processing device. The processing device may be another example of the apparatus 600. The IOD and apparatus 600 may be communicatively coupled. For example, prior to transmitting the first images, the method may comprise establishing a communication channel between the IOD and the processing device. The communication channel may correspond to the communication channel 406 discussed with reference to Fig. 4a. As such, the skilled person is directed to the discussion of Fig. 4a for further detail.

[0159] The first images may be transmitted to the processing device periodically and / or as part of a video stream.

[0160] Block 504 may be performed by a transmitting device of the IOD.

[0161] At block 506 of Fig. 5, the method comprises receiving, from the processing device, one or more first signals indicative of one or more teeth being present in one or more of the first images transmitted to the processing device.

[0162] Block 506 may be performed by a receiving device of the IOD. Block 506 may correspond to block 104. As such, the skilled person is referred to the discussion of block 104 for further detail.2025PF00031

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[0164] At block 508, the method comprises, responsive to receiving the one or more first signals, causing activation of the first mode of the EM radiation source arrangement. In the first mode, the EM radiation source is capable of causing photobiological damage to the subject. For example, the IOD may use the one or more first signals to cause activation of the first mode.

[0165] Block 508 may correspond to the activation of the first mode of the EM radiation source arrangement discussed with reference to Fig. 1. As such, the skilled person is referred to the discussion of this figure for further detail.

[0166] It will be appreciated that any of blocks 502, 504, 506, and 508 may be performed responsive to the IOD receiving an activation indication.

[0167] If the one or more first signals are not received by the IOD, the method may comprise performing an action. The action may comprises one or more of: preventing activation of the first mode; not causing activation of the first mode; deactivating the first mode; deactivating the EM radiation source arrangement; and causing activation of the second mode of the EM radiation source arrangement. lin the second mode, the EM radiation source is not capable of causing photobiological damage to the subject.

[0168] The method may further comprise obtaining additional images using the imaging device whilst the EM radiation source arrangement is activated in the first mode. The additional images may correspond to the additional images discussed above in reference to the method of Fig. 1.

[0169] For further detail, an example implementation of the embodiments described herein is now provided. Assuming an IOS device according to embodiments disclosed herein is equipped with a start button, a user may activate the IOS using the start button, resulting in the IOS emitting white light at a low intensity (i.e., activation of the second mode). This presents no significant photobiological hazard to a subject of a scan performed using the IOS device. The white light can be utilized to view what is in front of a camera of the IOS device, and, for example, the resulting images can be sent to an external processing device (e.g., a smartphone or a cloud provider) for analysis. Additionally or alternatively, the images can be directly processed on the IOS device.

[0170] The images can then be analysed according to the methods described herein. If no teeth are detected as a result of the analysis, the external processing device will cease (or avoid) sending ACK signals to the IOS device (or the IOS device will cease (or avoid) generating the ACKs), prompting the IOS device to prevent activation of (or not activate) a near-UV light source of the IOS device (i.e., deactivate, prevent activation of, or not activate the first mode). This safety feature ensures that photobiological safety risks are minimal or non-existent in case the user accidentally positions the scanner near the eye.

[0171] The IOS device can be caused to operate in safe light conditions, such as white light and low intensity visible light, until the presence of teeth is detected using Al or CV algorithms. Once teeth are detected, the IOS device can switch to other settings or modes, such as a QLF mode (i.e., the first mode) to perform its intended functions. This approach ensures that the IOS device operates safely and2025PF00031

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[0173] prevents hazardous situations, such as exposure of a subject to harmful radiation, which can cause various adverse health effects like skin bums or eye damage.

[0174] The embodiments disclosed herein enable IODS comprising potentially dangerous EM radiation source arrangements to be used safely by a wide range of users across different age groups and populations. Potential misuse of such IODs may be prevented, meaning hazardous situations can be avoided whilst the IODs can still be used, for example, to induce QLF of tooth enamel via the EM radiation source arrangement.

[0175] It will be appreciated that embodiments of the present disclosure may be performed to control the operation of any suitable IOD, such as IOS devices, particularly where the IOD is has the potential to cause harm if misused (e.g., an EM radiation source arrangement may be activated with the wrongs settings or whilst the IOD is not in a suitable location).

[0176] Advantageously, the embodiments disclosed herein may be used to provide an IOS device that can perform plaque detection to inform users as to where more effective brushing is required.

[0177] In an embodiment of the disclosure, there is provided a device using light to scan in the user’s oral cavity comprising: an IOS device capable of capturing scan data;

[0178] a processor adapted to analyse the data to determine if teeth are present in the area being scanned; and a mechanism to revert to safe light conditions when teeth are not present.

[0179] Fig. 6 is a schematic diagram illustrating an apparatus 600 for implementing method according to embodiments of the disclosure.

[0180] As illustrated in Fig. 6, the apparatus 600 comprises one or more processors 602. The one or more processors 602 can be implemented in numerous ways, with software and / or hardware, to perform the various functions described herein. The one or more processors 602 can comprise a plurality of software and / or hardware modules, each configured to perform, or that are for performing, individual or multiple steps of the method described herein.

[0181] The one or more processors 602 may comprise, for example, one or more microprocessors, one or more multi -core processors and / or one or more digital signal processors (DSPs), one or more processing units, and / or one or more controllers (e.g. one or more microcontrollers) that may be configured or programmed (e.g. using software or computer program code) to perform the various functions described herein. The one or more processors 602 may be implemented as a combination of dedicated hardware (e.g. amplifiers, pre-amplifiers, analog -to-digital convertors (ADCs) and / or digital -to-analog convertors (DACs)) to perform some functions and one or more processors (e.g. one or more programmed microprocessors, DSPs and associated circuitry) to perform other functions.

[0182] The one or more processors 602 can be configured to perform the method(s) described herein.

[0183] In particular, the apparatus 600 may be for controlling operation of an IOD that is operable in an oral cavity of a subject according to an embodiment. In such embodiments, the apparatus may be a processing device that is external to the IOD, in which case the apparatus may be2025PF00031

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[0185] communicatively coupled to the IOD (e.g., via the communications interface 610, discussed in more detail below). In such embodiments, the apparatus 600 may be a wireless device (e.g. a mobile phone, a smart phone, a tablet, a laptop, or any other wireless device), a processor of a cloud computing network, a computing device (e.g., a laptop, a tablet, etc) or any other suitable processing device. In particular, the one or more processors 602 may be configured to cause the apparatus to perform the method described with reference to Fig. 1. For example, the one or more processors 602 may be configured to cause the apparatus 600 to perform the embodiments of the method described herein, such as the embodiments of the method described with reference to Fig. 1.

[0186] Alternatively, the apparatus 600 may be, or be incorporated (e.g., embedded) in, an IOD according to an embodiment. In such embodiments, the one or more processors 602 may be configured to cause the apparatus to perform the method described with reference to Fig. 1 and / or Fig. 5. For example, the one or more processors 602 may be configured to cause the apparatus 600 to perform the embodiments of the method described herein, such as the embodiments of the method described with reference to Fig. 1 and / or Fig. 5.

[0187] It will be appreciated that (regardless of whether the IOD is, comprises, or is communicatively coupled to the apparatus 600), the IOD comprises an imaging device. The imaging device may comprise an image sensor that is sensitive to visible light. The imaging device may be a camera. An example camera is an RGB camera. However, the imaging device may be any suitable device that can be embedded in an IOD and can capture images of an oral cavity.

[0188] The IOD also comprises an EM radiation source arrangement (e.g., one or more sources of EM radiation), as defined herein. The EM radiation source arrangement is capable of operating in the first mode (and, optionally, the second mode) defined herein.

[0189] The IOD may also comprise an activation mechanism for initiating the method of Fig. 1 and / or Fig. 5. The activation mechanism may be a button, a switch, an actuator, and / or any other operable element that is configurable to provide an activation indication to the apparatus 600 and / or the IOD. The activation indication may indicate that a user of the IOD wishes to, intends to, or is requesting to cause activation of the first mode of the EM radiation source arrangement. As such, the activation indication may indicate that one or more steps of the method of Fig. 1 and / or Fig. 5 is to be performed. For example, actuation of the activation mechanism may cause performance of any of the blocks of Fig. 1 and / or Fig. 5.

[0190] As illustrated in Fig. 6, the apparatus 600 may comprise at least one memory 606.

[0191] Alternatively or in addition, at least one memory 606 may be external to (e.g. separate to or remote from) the apparatus 600. For example, another apparatus may comprise at least one memory 606 according to some embodiments. A hospital database may comprise at least one memory 606, at least one memory 606 may be a cloud computing resource, or similar. The one or more processors 602 of the apparatus 600 may be configured to communicate with and / or connect to at least one memory 606. The at least one memory 606 may comprise any type of non-transitory machine-readable medium, such as cache or system memory including volatile and non-volatile computer memory such as random access memory (RAM),2025PF00031

[0192] 23

[0193] static RAM (SRAM), dynamic RAM (DRAM), read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), and electrically erasable PROM (EEPROM). At least one memory 606 can be configured to store program code that can be executed by the one or more processors 602 of the apparatus 600 to cause the apparatus 600 to operate in the manner described herein.

[0194] Alternatively or in addition, at least one memory 606 can be configured to store information required by or resulting from the method described herein. For example, at least one memory 606 may be configured to store images obtained by an imaging device in the IOD, the ML model and / or classical algorithms used to analyze said images, an activation configuration for the first mode and / or second mode of the EM radiation source arrangement, or any other information, or any combination of information, required by or resulting from the method described herein. The one or more processors 602 of the apparatus 600 can be configured to control at least one memory 606 to store information required by or resulting from the method described herein.

[0195] As illustrated in Fig. 6, the apparatus 600 may comprise at least one user interface 608. Alternatively or in addition, at least one user interface 608 may be external to (e.g. separate to or remote from) the apparatus 600. The one or more processors 602 of the apparatus 600 may be configured to communicate with and / or connect to at least one user interface 608. One or more processors 602 of the apparatus 600 can be configured to control at least one user interface 608 to operate in the manner described herein.

[0196] A user interface 608 can be configured to render (or output, display, or provide) information required by or resulting from the method described herein. For example, one or more user interfaces 608 may be configured to render (or output, display, or provide) images obtained by the IOD, indications of whether first and / or second signals have been generated by the apparatus, or any other information, or any combination of information, required by or resulting from the method described herein. Alternatively or in addition, one or more user interfaces 608 can be configured to receive a user input. For example, one or more user interfaces 608 may allow a user to manually enter information or instructions, interact with and / or control the apparatus 600. Thus, one or more user interfaces 608 may be any one or more user interfaces that enable the rendering (or outputting, displaying, or providing) of information and / or enables a user to provide a user input.

[0197] The user interface 608 may comprise one or more components for this. For example, one or more user interfaces 608 may comprise one or more switches, one or more buttons, a keypad, a keyboard, a mouse, a display or display screen, a graphical user interface (GUI) such as a touch screen, an application (e.g. on a smart device such as a tablet, a smart phone, or any other smart device), or any other visual component, one or more speakers, one or more microphones or any other audio component, one or more lights (e.g. one or more light emitting diodes, LEDs), a component for providing tactile or haptic feedback (e.g. a vibration function, or any other tactile feedback component), a smart device (e.g. a smart mirror, a tablet, a smart phone, a smart watch, or any other smart device), or any other user interface, or2025PF00031

[0198] 24

[0199] combination of user interfaces. One or more user interfaces that are controlled to render information may be the same as one or more user interfaces that enable the user to provide a user input.

[0200] As illustrated in Fig. 6, the apparatus 600 may comprise at least one communications interface (or communications circuitry) 610. Alternatively or in addition, at least one communications interface 610 may be external to (e.g. separate to or remote from) the apparatus 600. A communications interface 610 can be for enabling the apparatus 600, or components of the apparatus 600 (e.g. one or more processors 602, one or more sensors 604, one or more memories 606, one or more user interfaces 608 and / or any other components of the apparatus 600), to communicate with and / or connect to each other and / or one or more other components. For example, one or more communications interfaces 610 can be for enabling one or more processors 602 of the apparatus 600 to communicate with and / or connect to one or more sensors 604, one or more memories 606, one or more user interfaces 608 and / or any other components of the apparatus 600.

[0201] A communications interface 610 may enable the apparatus 600, or components of the apparatus 600, to communicate and / or connect in any suitable way. For example, one or more communications interfaces 610 may enable the apparatus 600, or components of the apparatus 600, to communicate and / or connect wirelessly, via a wired connection, or via any other communication (or data transfer) mechanism. In some wireless embodiments, for example, one or more communications interfaces 610 may enable the apparatus 600, or components of the apparatus 600, to use radio frequency (RF), Bluetooth, or any other wireless communication technology to communicate and / or connect.

[0202] Fig. 7 is a block diagram illustrating an example processor 700 according to embodiments of the disclosure. Processor 700 may be used to implement one or more processors described herein, for example, processor 602 shown in Fig. 6. Processor 700 may be any suitable processor type including, but not limited to, a microprocessor, a microcontroller, a digital signal processor (DSP), a field programmable array (FPGA) where the FPGA has been programmed to form a processor, a graphical processing unit (GPU), an application specific circuit (ASIC) where the ASIC has been designed to form a processor, or a combination thereof.

[0203] The processor 700 may include one or more cores 702. The core 702 may include one or more arithmetic logic units (ALU) 704. In some embodiments, the core 702 may include a floating point logic unit (FPLU) 706 and / or a digital signal processing unit (DSPU) 708 in addition to or instead of the ALU 704.

[0204] The processor 700 may include one or more registers 712 communicatively coupled to the core 702. The registers 712 may be implemented using dedicated logic gate circuits (e.g., flip-flops) and / or any memory technology. In some embodiments the registers 712 may be implemented using static memory. The register may provide data, instructions and addresses to the core 702. In some embodiments, processor 700 may include one or more levels of cache memory 710 communicatively coupled to the core 702. The cache memory 710 may provide computer-readable instructions to the core 702 for execution. The cache memory 710 may provide data for processing by the core 702. In some2025PF00031

[0205] 25

[0206] embodiments, the computer-readable instructions may have been provided to the cache memory 710 by a local memory, for example, local memory attached to the external bus 716. The cache memory 710 may be implemented with any suitable cache memory type, for example, metal -oxide semiconductor (MOS) memory such as static random access memory (SRAM), dynamic random access memory (DRAM), and / or any other suitable memory technology.

[0207] The processor 700 may include a controller 714, which may control input to the processor 700 from other processors and / or components included in a system and / or outputs from the processor 700 to other processors and / or components included in the system. Controller 714 may control the data paths in the ALU 704, FPLU 706 and / or DSPU 708. Controller 714 may be implemented as one or more state machines, data paths and / or dedicated control logic. The gates of controller 714 may be implemented as standalone gates, FPGA, ASIC or any other suitable technology. The registers 712 and the cache 710 may communicate with controller 714 and core 702 via internal connections 720A, 720B, 720C and 720D. Internal connections may implemented as a bus, multiplexor, crossbar switch, and / or any other suitable connection technology.

[0208] Inputs and outputs for the processor 700 may be provided via a bus 716, which may include one or more conductive lines. The bus 716 may be communicatively coupled to one or more components of processor 700, for example the controller 714, cache 710, and / or register 712. The bus 716 may be coupled to one or more components of the system.

[0209] The bus 716 may be coupled to one or more external memories. The external memories may include Read Only Memory (ROM) 732. ROM 732 may be a masked ROM, Electronically Programmable Read Only Memory (EPROM) or any other suitable technology. The external memory may include Random Access Memory (RAM) 733. RAM 733 may be a static RAM, battery backed up static RAM, Dynamic RAM (DRAM) or any other suitable technology. The external memory may include Electrically Erasable Programmable Read Only Memory (EEPROM) 735. The external memory may include Flash memory 734. The External memory may include a magnetic storage device such as disc 736. In some embodiments, the external memories may be included in a system, such as the system in Fig. 4.

[0210] There is provided a computer program comprising instructions which, when executed by a processor (such as one or more processors 602 of the apparatus 600 or the processor 702), cause the processor to perform at least part of, or all of, the method described herein.

[0211] There is provided a computer program product comprising a computer readable medium. The computer readable medium has a computer readable code embodied therein. The computer readable code is configured such that, on execution by a suitable computer or processor (such as one or more processors 602 of the apparatus 600 or the processor 702), the computer or processor is caused to perform the method described herein. The computer readable medium may be, for example, any entity or device capable of carrying the computer program product. For example, the computer readable medium may include a data storage, such as a ROM (such as a CD-ROM or a semiconductor ROM) or a magnetic2025PF00031

[0212] 26

[0213] recording medium (such as a hard disk). Furthermore, the computer readable medium may be a transmissible carrier, such as an electric or optical signal, which may be conveyed via electric or optical cable or by radio or other means. When the computer program product is embodied in such a signal, the computer readable medium may be constituted by such a cable or other device or means. Alternatively, the computer readable medium may be an integrated circuit in which the computer program product is embedded, the integrated circuit being adapted to perform, or used in the performance of, the method described herein.

[0214] There is thus provided herein an apparatus, method, and computer program product for controlling operation of an IOD, which address the limitations associated with the existing techniques.

[0215] It will be understood that at least some or all of the method steps described herein can be automated. That is, at least some or all of the method steps described herein can be performed automatically. The method described herein can be a computer-implemented method.

[0216] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments.

[0217] Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the principles and techniques described herein, 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 the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfil the functions of several items recited in the claims. 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. A computer program may be stored or distributed on a 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 telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope.

Claims

2025PF0003127CLAIMS:

1. A computer-implemented method (100) of controlling operation of an intra-oral device, IOD, (404, 408) that is operable in an oral cavity of a subject, the method comprising:analyzing (102) first images obtained by an imaging device in the IOD to determine whether one or more teeth are present in one or more of the first images; andgenerating (104) one or more first signals if the one or more teeth are determined to be present in one or more of the first images, wherein the one or more first signals are configured to cause activation of a first mode of an electromagnetic, EM, radiation source arrangement in the IOD, wherein in the first mode, the EM radiation source arrangement is capable of causing photobiological damage to the subject.

2. The method as claimed in claim 1, wherein if the one or more teeth are determined not to be present in one or more of the first images, the method further comprises performing an action, wherein the action comprises one or more of:preventing activation of the first mode;not causing activation of the first mode;deactivating the first mode;deactivating the EM radiation source arrangement; andcausing activation of a second mode of the EM radiation source arrangement, wherein in the second mode, the EM radiation source arrangement is not capable of causing photobiological damage to the subject.

3. The method as claimed in claim 2, wherein the action is performed by one or more of:preventing generation of the one or more first signals;not generating the one or more first signals; andgenerating one or more second signals configured to prevent activation of the first mode and / or to cause activation of the second mode.

4. The method as claimed in any one of the preceding claims, wherein the first images are analyzed using one or more of:a machine learning, ML, model trained to identify teeth in image data input into the ML model;2025PF0003128morphological operations that are operable to identify teeth in image data to which the morphological operations are applied; anda classical algorithm configured to identify teeth in image data to which the classical algorithm is applied.

5. The method as claimed in any one of the preceding claims, wherein the method is performed by one or more of:at least one processor of a cloud computing network;at least one processor of a wireless device;at least one processor of a computing device; andwherein the one or more first signals are output to the IOD.

6. The method as claimed in claim 5, wherein the first mode is activated only if the one or more first signals are received by the IOD.

7. The method as claimed in any one of claims 1 to 5, wherein the method is performed by the IOD, and the method further comprises using the one or more first signals to activate the first mode.

8. A method performed by an intra-oral device, IOD, that is operable in an oral cavity of a subject, the method comprising:obtaining (502) first images using an imaging device in the IOD;transmitting (504) the first images to a processing device external to the IOD; receiving, from the processing device, one or more first signals indicative of one or more teeth being present in one or more of the first images transmitted to the processing device; and responsive to receiving the one or more first signals, causing (508) activation of a first mode of an electromagnetic, EM, radiation source in the IOD, wherein in the first mode, the EM radiation source is capable of causing photobiological damage to the subject.

9. The method according to claim 8, wherein if the one or more first signals are not received by the IOD, the method comprises performing an action, wherein the action comprises one or more of:preventing activation of the first mode;not causing activation of the first mode;deactivating the first mode;deactivating the EM radiation source arrangement; andcausing activation of a second mode of the EM radiation source arrangement, wherein in the second mode, the EM radiation source is not capable of causing photobiological damage to the subject.2025PF000312910. The method as claimed in any one of the preceding claims, wherein in the first mode, the EM radiation source arrangement is further capable of causing tooth enamel to fluoresce at a different wavelength to plaque in order to increase the visibility of plaque in the oral cavity.

11. The method as claimed in any one of the preceding claims, wherein in the first mode, an emission peak of radiation emitted from the EM radiation source arrangement activated in the first mode has a wavelength at or around 405 nm.

12. An apparatus for controlling operation of an intra-oral device, IOD, that is operable in an oral cavity of a subject, the apparatus comprising one or more processors configured to cause the apparatus to:analyze (102) first images obtained by an imaging device in the IOD to determine whether one or more teeth are present in one or more of the first images; andgenerate (104) one or more first signals if the one or more teeth are determined to be present in one or more of the first images, wherein the one or more first signals are configured to cause activation of a first mode of an electromagnetic, EM, radiation source arrangement in the IOD, wherein in the first mode, the EM radiation source arrangement is capable of causing photobiological damage to the subject.

13. An intra-oral device, IOD, (404) that is operable in an oral cavity of a subject, the IOD comprising one or more processors configured to cause the IOD to:obtain (502) first images using an imaging device in the IOD;transmit (504) the first images to a processing device (402) external to the IOD; receive (506), from the processing device, one or more first signals indicative of one or more teeth being present in one or more of the first images transmitted to the processing device; and responsive to receiving the one or more first signals, cause (508) activation of a first mode of an electromagnetic, EM, radiation source in the IOD, wherein in the first mode, the EM radiation source is capable of causing photobiological damage to the subject.

14. A system (400) comprising an apparatus (402) according to claim 12 and an IOD (404) according to claim 13, wherein the apparatus is operable to communicate with the IOD.

15. A computer program product comprising a computer readable medium, the computer readable medium having a computer readable code embodied therein, the computer readable code being configured such that, on execution by a suitable computer or processor:2025PF0003130the computer or processor performs the method as claimed in any one of claims 1 to 7, 10, and 11; orthe computer or processor causes an intra-oral device, IOD, to perform the method as claimed in any one of claims 8 to 11.

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