Patent Application
20240382081
The present disclosure relates to a dental transillumination device and system for home use. Such a system may be used by a person who is not a dental practitioner, to be able to identify dental issues (such as caries, for example) without needing to visit a dentist.
It is common for dental patients to feel anxiety associated with visiting a dentist. This can lead to people avoiding a visit to their dentist, thereby missing the opportunity to identify dental issues early, whilst they are easy to treat. In some areas, it is difficult to access dental care, for example because there is no dentist close by, or because the cost of visiting a dentist is prohibitive. It is therefore desirable to provide some means to monitor dental health at home. If dental issues are identified at home, this can provide the motivation for people to visit the dentist, especially if they would otherwise be reluctant to do so. On the other hand, if a dental patient is able to determine at home that there are no issues with their teeth, they can defer a trip to the dentist.
According to the Centres for Disease Control and Prevention, 91% % of adults aged 20 to 64 in the US have dental caries (commonly referred to as tooth decay or cavities). If caries is identified early, preventative measures can be suggested by a dentist in order to prevent further deterioration in the condition of the teeth. Without such preventative measures, the caries may worsen, necessitating more invasive treatments (such as drilling the tooth and filling the cavity).
Caries can be categorised visually by a dentist as one of category 1 to category 6 according to the International Caries Detection and Assessment System (ICDAS). The visual appearance associated with each code is set out below:
Caries categorised as code 3 or above should be seen by a dentist, for treatment and/or ongoing monitoring.
As well as visual examination, a method traditionally used by dentist in order to identify caries is the use of x-rays to produce a radiograph of the patient's teeth. However, since x-rays are ionising radiation, there is understandable reluctance to use x-ray imaging too frequently. Typically, even those at high risk of dental problems will not have x-rays taken more frequently than once every 6 months. X-ray imaging must of course be carried out by a dental professional, and cannot be done at home by a patient themselves.
Dental transillumination is another technique which also allows for the identification of caries. In this technique, a tooth is illuminated by a bright light source which illuminates from one side of the tooth or both sides, typically with near infra-red (NIR) light. The light passes through the tooth and the tooth is imaged in the occlusal/incisal direction (the direction toward the biting surface of the teeth). Due to the optical properties of caries tissue, caries appear as a dark shadow on the image. Transillumination facilitates detection of caries in real-time, and since the light used is non-ionising, it can be carried out frequently.
Existing transillumination devices are very expensive and unsuitable for home use. In particular, existing device require the expertise of a dentist to capture images of sufficient quality to identify caries. Typically, such devices comprise a head portion with two parallel flexible wing portions which fit snugly either side of a tooth to be imaged. Light is incident onto the tooth from one or both of the wing portions, and the flexibility of the wing portions should allow for the light source to be maintained close to the tooth surface. However, such devices have been found to have shortcomings—for example, it is common for images of canines and incisors to be overexposed (due to too much light entering the tooth) whereas images of molars may be underexposed (due to insufficient light entering the tooth). It therefore requires the expertise of a dentist to position the device in such a way that satisfactory images are captured.
In view of the foregoing, it is desirable to provide a dental transillumination system for home use which would allow a person which is not a dental practitioner to be able to identify dental issues without needing to visit a dentist.
Moreover, such a device should be robust, and have as simple a construction as possible to allow for production in high numbers, at a relatively low cost.
A first aspect of the present invention provides a main body portion for a dental examination instrument, the main body portion comprising: an outer housing; an inner cradle to be received within the outer housing; and a plurality of internal components held within the inner cradle, wherein the inner cradle comprises a plurality of resilient projections which clip the plurality of internal components onto the cradle.
The internal components may comprise one or more components selected from the following: a rechargeable battery, an inductor for charging the rechargeable battery, a main PCB with a controller mounted thereto, a flex PCB, and a camera.
The main body portion may comprise a neck portion housing an optical assembly, wherein the inner cradle extends into the neck portion and the optical assembly is secured by resilient projections which clip the optical assembly onto the cradle.
The neck portion may be sized so as to allow a user to close their mouth around the neck portion in use. Movement of the neck portion around the user's mouth does not require the user to open their mouth so wide as to cause discomfort.
The base portion is located at an opposite end to the neck portion and the middle portion may be located between the base portion and the neck portion. The middle portion may be configured to be held by a user during use of the device.
The optical assembly may comprise an aperture, and/or a prism, and/or a lens. A plurality of lenses may be provided; for example, the optical assembly may comprise a plurality of plano-convex lenses (for example, three).
The optical assembly may comprise a plurality of lenses which are held by spacers (for example, cylindrical spacers) to maintain the correct optical path.
The components within the main portion may be held in place within the cradle without the use of screws or other similar fasteners, so that no screws (or other similar fasteners) are present within the main body portion. This reduces the cost and increases the ease of manufacture of the main portion. The components may be held in place within the cradle by a frictional fit with the cradle.
The invention may extend to a transillumination device for imaging teeth comprising the main body portion of any of the relevant aspects relating to main body portions described herein (optionally including any of the optional features described herein), further comprising a removable tip mountable onto the main body portion, the removable tip comprising a plurality of LEDs for illuminating a tooth for transillumination imaging of the tooth.
The removable tip may be the head portion of the any relevant aspect relating to a head portion described herein.
According to another aspect of the present invention, there is provided a head portion for a dental transillumination device, comprising: a central portion, arranged to receive light from a tooth for imaging an occlusal/incisal view of the tooth, and first and second flexible wing portions extending from the central portion, wherein the first flexible wing portion is configured to contact a first side of the tooth, and the second flexible wing portion is configured to contact a second side of the tooth, opposite to the first side, wherein the first flexible wing portion comprises a first plurality of illumination sources for illuminating the tooth from the first side, and the second flexible wing portion comprises a second plurality of illumination sources for illuminating the tooth from the second sides, and wherein the first and second plurality of illumination sources are mounted on a flex PCB.
A controller chip may also be mounted on the flex PCB for controlling the illumination sources.
The illumination sources may be LEDs.
The head portion may comprise two support arms extending from the central portion which support the flex PCB.
The head portion may comprise a flexible over-moulding which encapsulates the flex PCB.
Each of the first and second flexible wing portions may comprise a projection (formed by the over-moulding) arranged to space apart the illumination sources from the tooth.
Each of the first and second flexible wing portions may comprise a projection (formed by the over-moulding) arranged to prevent or reduce light from the illumination sources directly falling into a window in the central portion.
The central portion may comprises a plurality of alignment projections (formed by the over-moulding) bracketing the first and second flexible wing portions and arranged substantially perpendicular to the first and second flexible wing portions.
The flexible over-moulding may comprise a window overlying the LEDs which is transparent to IR light, wherein the window is formed from a different material than the remainder of the over-moulding.
Optionally, the head portion comprises pogo connectors for connecting to a main body portion as described below. These may be mounted to the flex PCB and protrude through a housing of the head portion.
Another aspect of the invention provides a transillumination device for imaging teeth comprising a vibration motor and a LED for providing feedback to a user of the transillumination device.
The LED may be a RGB LED. Alternatively, the LED may be a single-color LED. Optionally, a plurality of LEDs are provided.
The transillumination device may comprise a main body portion to be held by the user in their hand. The transillumination device may have a form-factor similar to that of an electric toothbrush, for example. The main body portion may therefore comprise a housing which is broadly cylindrical in shape, forming a handle to be held by the user.
Where a plurality of LEDs are provided, these may be spaced around the circumference of the main body portion, within the main body portion. The LEDs may shine through the housing when illuminated, i.e. there is no need to provide a window in the housing for the LEDs to shine through. This simplifies manufacture of the device.
Another aspect of the invention provides a main body portion for a dental examination instrument, the main body portion comprising: an elongate housing; and a flex PCB housed within the housing, the flex PCB extending along at least a partial extent of the length of the elongate housing, wherein the flex PCB comprises a portion which has been bent so as to lie in a plane transverse to the length of the elongate housing.
The portion which has been bent so as to lie in a plane transverse to the length of the elongate housing may comprise a section (optionally annular in shape) of the flex PCB comprising a LED (for providing feedback to the user). Optionally a plurality of LEDs are provided. The LEDs may be spaced around the section (optionally evenly spaced around the annular section). The LED(s) is/are optionally configured to shine through the housing when illuminated.
The portion which has been bent so as to lie in a plane transverse to the length of the elongate housing may comprise an interface portion at a first end of the flex PCB, the interface portion comprising connector pads for electrical connection. The connector pads may be aligned with holes in the elongate housing, the holes being sized to receive pogo connectors for contacting the connector pads. The pogo connectors may be the pogo connectors described above.
The flex PCB may comprise first and second portions which have been bent so as to lie in a plane transverse to the length of the elongate housing. The first portion may comprise a section (optionally annular in shape) of the flex PCB comprising a LED (optionally a plurality of LEDs)—as described above. The second portion may comprise an interface portion at a first end of the flex PCB, the interface portion comprising connector pads for electrical connection to the flex PCB. The connector pads may be aligned with holes in the elongate housing, the holes being sized to receive pogo connectors for contacting the connector pads. The pogo connectors may be the pogo connectors described above.
The flex PCB may comprise a plurality of bends.
The flex PCB may be connected to a main PCB. The main PCB may be a rigid PCB. The rigid PCB may comprise a controller chip mounted thereto. Electrical connection paths may run along the flex PCB to contact corresponding paths on the main PCB, for connection to the controller. Electrical connection paths may extend from the controller to the LEDs on the first portion, and/or from the controller to the connector pads on the second portion.
The connector pads are for connecting the controller in the main body portion to a flex PCB in a head portion (i.e. a second flex PCB), the flex PCB in the head portion comprising a controller chip and a plurality of LEDs. The LEDs are controllable by the controller in the main body portion and/or the controller chip in the head portion. The LEDs are controllable individually, in pairs or in groups.
Another aspect of the present invention provides a main body portion for a dental examination instrument, the main body portion comprising: an outer housing including a base portion, a neck portion, and a middle portion positioned between the base portion and the neck portion, and an inductor for charging a rechargeable battery, wherein the inductor is positioned in the middle portion.
The main body portion may comprise a rechargeable battery (or a plurality of rechargeable batteries).
It is advantageous for a dental examination instrument to perform a number of different functions, e.g. to be able to communicate wirelessly (via Bluetooth for example) with a user's smart device (e.g. mobile phone, tablet, laptop, desktop PC, or a purpose-built smart device) whilst the instrument is in use, i.e. being held by the user in their hand. Since water in the user's body (e.g. in their hand/mouth) absorbs Wi-Fi signals (e.g. 2.45 GHz radio waves), it is advantageous to position components such as a W-Fi antenna at a position at which the user's hand or mouth does not surround the Wi-Fi antenna. A suitable position is the base of the main body portion of the transillumination device. However, the inductor typically also absorbs Wi-Fi signals (e.g. 2.45 GHz radio waves). For this reason, to allow the Wi-Fi antenna to be positioned in the base, in the present invention the inductor is moved away from the conventional position in the base to the middle portion.
The main body portion may comprise a Wi-Fi and/or Bluetooth antenna for communication with a smart device, wherein the Wi-Fi and/or Bluetooth antenna is positioned in the base portion. This ensures more reliable communication via the antenna.
Alternatively, or additionally, the main body portion may comprise a wired connection for communication with a smart device. The wired connection may be in the base portion.
The rechargeable battery may be located in the middle portion.
The inductor may comprise a ferrite rod.
The inductor may comprise a conductive coil surrounding at least part of the ferrite rod, and wherein the conductive coil may comprise copper.
As an alternative to a rechargeable battery, the device may omit a battery altogether, and instead may receive power from another power source via a wired connection (for example, a wired connection for connection to a smart device).
Another aspect of the present invention provides a charging system comprising an inductive charging device and a transillumination device as described above (including the main body portion of any aspect described herein and any optional features described herein), the inductive charging device comprising a charging device inductor, being configured to charge a rechargeable battery of the transillumination device via the inductor of the transillumination device and being configured to sit next to or wrap around the middle portion of the transillumination device during charging. Accordingly, the inductor of the transillumination device can be provided in the middle portion. In this way, components such as the wireless antenna described herein can be positioned in the base of the transillumination device.
The charging device inductor may comprise a ferrite rod.
The charging device inductor may comprise a conductive coil surrounding at least part of the ferrite rod, and the conductive coil may comprise copper.
According to another aspect the present invention provides a main body portion for a dental examination instrument, the main body portion comprising: an outer housing including a base portion, a middle portion and a neck portion, wherein the neck portion comprises a transparent window in its exterior; and an optical assembly within the neck portion, wherein the optical assembly comprises a camera that is positioned opposite the transparent window.
Here, transparent means transparent to at least IR light.
By having a camera opposite the transparent window, the number of optical components required to transmit light from the window to the camera is minimized as the camera lies in a straight line path from the window.
The optical assembly may comprise a lens and/or an aperture. The optical assembly optionally does not include a prism.
The camera may be positioned directly in line with, and behind, the transparent window.
The transparent window may be formed from sapphire glass. This ensures the window is resistant to damage such as scratching.
The transparent window may be configured to be heated. The main body portion may comprise a heater for this purpose, and/or the main body may be configured to conduct ambient or waste heat from other components to the transparent window.
According to another aspect the present invention provides a main body portion for a dental examination instrument, the main body portion comprising: an outer housing including a base portion, a middle portion and a neck portion, wherein the neck portion comprises a transparent window in its exterior; and an optical assembly within the neck portion, wherein the optical assembly comprises a camera that is configured to receive light transmitted through the transparent window, and wherein the transparent window is configured to be heated.
As the transparent window is part of the exterior of the neck portion, it may be exposed to conditions in a user's mouth (for example heat and humidity), which has the potential to cause condensation on the transparent window during use. This has a detrimental effect on imaging by the camera. By heating the transparent window in use, condensation/fogging that would normally form on the transparent window can be avoided. The quality of images captured by the camera can therefore be maintained.
The optical assembly may comprise a frame configured to conduct heat to the transparent window. The frame may be metallic. For example, the frame may be made of brass. The frame may be in thermal contact with a heater.
The heater may be a resistive heater. The heater may comprise a high resistance wire, configured to generate heat when a current passes through it. Heat may be conducted to the frame from the heater (high-resistance wire) via soldered connections between the wire and the frame.
The frame may hold the transparent window in place. The heater may be arranged to heat the transparent window to a target temperature of at least 30° C., or at least 35° C. The heater may be arranged to heat the transparent window to a target temperature of approximately 40° C. The heater may be arranged to heat the transparent window to a target temperature within 1 minute, optionally within 30 seconds, and optionally within 20 seconds. The transparent window may comprise sapphire glass.
The optical assembly may comprise a lens and/or an aperture. The optical assembly may be mounted on a flexible PCB.
According to another aspect, the present invention provides a main body portion for a dental examination instrument, the main body portion comprising: an outer housing; two rigid PCBs oriented substantially at a right angle to one another and positioned within the outer housing; and a plurality of internal components mounted to the rigid PCBs.
By utilizing two PCBS at right angles to one another the space available to mount components is maximized.
The internal components may be any of the internal components described herein. In particular, the internal components may be one or more components selected from the following: a rechargeable battery, an inductor for charging the rechargeable battery, a main PCB with a controller mounted thereto, LEDs, a flex PCB, a Wi-Fi and/or Bluetooth antenna, and/or a wired connection.
The main body portion may comprise a pogo connector extending through the housing for connecting to a corresponding pogo connector on a head portion as previously discussed. This provides a way in which multiple head portions can be interchangeable with a main body portion. The pogo connector may be electrically connected to one of the rigid PCBs within the outer housing of the main body portion.
According to another aspect, the present invention provides a main body portion for a dental examination instrument, the main body portion comprising: an outer housing including a base portion and a middle portion, wherein the middle portion is configured to be held by a user during use; and a Wi-Fi and/or Bluetooth antenna, wherein the Wi-Fi and/or Bluetooth antenna is positioned in the base portion. In this way, the Wi-Fi and/or Bluetooth antenna is in a position where it is unobstructed by the user in use or, if present, the inductor described herein (in relation to the first aspect).
Any of the main body portions described herein may comprise a plurality of LEDs for providing feedback to a user. The LEDS may be positioned within the housing for example mounted on the PCBs described above. The main body portion may comprise light guides for guiding light from the LEDs to the interior surface of the housing, where it shines through the housing and is visible to a user. The use of light guides allows for the LEDS to be placed in a more convenient location within the housing.
Each of the aspects described above may be combined with each other (optionally including any of the optional features discussed above in respect of each aspect).
Certain preferred embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings, in which:
The transillumination device comprises a head portion 110 and a main body portion 150. The head portion 110 comprises a tip 112 which is shaped so as to fit over a user's tooth.
As shown in
As discussed in more detail below, the transillumination device 100 is capable of applying a number of different lighting conditions to the tooth. This is achievable by having a plurality of LEDs in the tip 112.
Arranging the LEDs in a rectangular/square configuration or a parallelogram/rhombus configuration (or in any configuration where one or more LEDs are closer to the gum-line than one or more other LEDs, and where one or more LEDs are laterally offset from one or more other LEDs) on each side of the tooth ensures that one or more of the LEDs on each side is close enough to the tooth to transilluminate the tooth. Additionally, such an arrangement allows for the provision of light from several different angles (for example, close to the gum-line, and further up the tooth, and from two lateral directions) so that all evidence of caries within the tooth (seen as shadows on a transillumination image) can be imaged. Providing a plurality of LEDs with different positions provides a range of options for LED placement relative to the tooth, thus providing a technical solution to the problem of finding optimal LED placement for transillumination for a user at home (which normally requires extensive training for a dentist to realise in a clinic setting using a single light source). Providing a plurality of LEDs also allows for variable levels of illumination by turning on different numbers of LEDs. This allows to get an increased amount of light into a large tooth (for example, a molar), whereas a lesser amount of light is needed for transillumination of a small tooth (for example, an incisor).
Each LED 122 is configured to emit near-IR light. Here, near-IR light is defined as light having a wavelength in the range of 780 nm to 3000 nm (in accordance with the ISO 20473 standard). In this case, the LEDs have a peak wavelength at approximately 850 nm and a spectral bandwidth of approximately 35 nm. The radiant intensity (at a forward current of 100 mA) is approximately 9 to 18 mW/sr, and typically is around 13 mW/sr. The flexible wing portions 116 are configured to flex outwardly slightly when positioned over the tooth, but a returning force acts against this outward flexing, so that the tip 112 grips onto the sides of the tooth. The flexing of the flexible wing portions 116 ensures that there is minimal clearance between each LED 122 and the surface of the tooth; this reduces stray light which could be detrimental to imaging, and also ensures that an appropriate amount of light penetrates into the tooth to allow for imaging.
The LEDs 122 may also be configured to emit light in the visible spectrum—this allows a user to visualise that the device is working.
The head portion 110 also comprises a sleeve portion 126 comprising a hollow, broadly cylindrical portion. The sleeve portion 126 is configured to be received over a neck portion 160 of the main body portion 150, such that the head portion 110 and the main body portion 150 clip together.
The removable nature of the head portion 110 allows for several different users, e.g. members of the same family to use the transillumination device 100, with each family member using a different head portion 110. To allow for identification of each head portion 110 with a particular user, the head portion comprises an RFID tag (not shown). The RFID tag is read by a user's smart device (e.g. a mobile telephone 200 having a display screen, as shown in
The central portion 114 of the tip 112 comprises a window 124 in the over-moulding 120. The window 124 is configured to face the occlusal/incisal surface of the user's tooth. When the head portion 110 is clipped onto the main body portion 150, the window 124 in the central portion 114 of the tip 112 aligns with a corresponding window 162 in the neck portion 160 of the main body portion 150.
In use, light from the tooth passes through the window 124 in the central portion 114, through the corresponding window 162 in the neck portion 160, and into the neck portion 160. The neck portion 160 holds an optical assembly for directing the light to a camera 170. The optical assembly (shown in
In this case, the camera 170 is a low-voltage CMOS device. The camera outputs colour images, which are converted to greyscale for further analysis. The transillumination device 100 may carry out such a conversion or this can be performed by user's smart device (in this case a mobile telephone 200). As an alternative, a monochromatic camera could be used. There may be filters, for example a software filter, coupled to the camera to filter out different parts of the spectrum. Image processing of captured images may be performed by the transillumination device 100 and/or the user's smart device 200 and/or by a remote server 300. Such image processing may include filtering by wavelength, exposure control, white balance, colour saturation, hue control, white pixel cancelling, and/or noise cancelling.
The transillumination device 100 comprises means for providing feedback to the user. This takes the form of a vibration motor (not shown) and a plurality of user-feedback LEDs 176 (in this case four) radially spaced around an annular portion 178 of a flex PCB 184, and which emit visible light through the material forming main body portion 150. Each LED 176 is an RGB LED (i.e. comprising a combination of 3 LEDs: one red; one green; and one blue in just a single package). In this way many colors of light can be produced by each LED. The feedback comprises an indication to the user that suitable images were or were not captured by the device in use (as discussed in more detail below). Alternatively or additionally, similar feedback can be provided by the user's smart device.
Control of the operation of the transillumination device 100 is by a controller 180 in the form of a system-on-a-chip microcontroller. The controller 180 comprises integrated Wi-Fi/Bluetooth capability. The controller may perform any of the image processing mentioned above. The controller 180 is located on a main PCB 182 which is connected to the battery 172. The main PCB 182 is also connected to the flex PCB 184. The flex PCB 184 comprises the annular portion 178 and an LED-interface portion 186 located at the end of the neck portion 160, as well as connector portions of the flex PCB 184 which run between the main PCB to the annular portion 178 and from the annular portion 178 to the LED-interface portion 186.
All connections between the controller 180 and the LEDs 176 on the annular portion 178 run along the flex PCB 184 (and onto the main PCB 182), and similarly all connections between the controller 180 and the connectors on the LED-interface portion 186 run along the flex PCB 184 (and onto the main PCB 182).
Forming the annular portion 178 and LED-interface portion 186 as portions of a flex PCB reduces the cost and complexity of assembly; if the annular portion 178 and LED-interface portion 186 were instead formed from rigid PCBs, then additional cable connections to the main PCB 182 would be needed. Moreover, using a flex PCB 184 enables the device to be kept compact; a flex PCB is very flat which enables a thinner neck portion 160 to be provided. Since cable connectors are not needed, this also allows to keep the size down.
A flex PCB is also used because its flexibility can be utilised to bend the PCB into a suitable shape-so the annular portion 178 and LED-interface portion 186 are arranged in a transverse direction to the axial extent of the main body portion 150.
When the head portion 110 is clipped onto the main body portion 150, the LED-interface portion 186 is electrically connected to the flex PCB 118 in the head portion 110. This connection is achieved via three pogo connectors 127 (see
The flex PCB 118 comprises an LED controller chip 125 for controlling each of the LEDs 122 individually (i.e. each LED 122 can be separately controlled independently of the status of any of the other LEDs 122). The control of the LEDs 122 is done automatically by the device, without any input from the user.
The main body portion 150 comprises an outer housing 152 (shown in
The transillumination device 100 may be turned on/off using a user's smart device 200. This control (and any other communication between the smart device 200 and transillumination device 100) can occur via a Bluetooth connection. Alternatively, one or more buttons may be present on the main body portion 150 for this purpose.
The prism 164, aperture 166 and three plano-convex lenses 168 are held within a portion of the inner cradle 154 extending into the neck portion 160. The lenses are held in cylindrical spacers to ensure that the correct optical path is maintained. Again, no screws are needed for securing the components of the optical assembly.
The outer housing 152 is formed from a durable and waterproof plastic, such as acrylonitrile butadiene styrene (ABS) plastic.
In brief, the mobile telephone 200 runs a software application (an app) which receives images from the transillumination device 100, performs processing based on those images, and then transmits the images to the cloud-based server 300. The cloud-based server 300 performs any further necessary processing of the images which has not already been carried out by the mobile telephone, and sends the results back to the mobile telephone 200, to be displayed to the user on the display screen of the mobile telephone 200.
Before using the transillumination device 100 for the first time, the user opens the app and is taken through a process whereby they register.
Registration of the user comprises the setting of a username and password, registration of an email address, acceptance of terms and conditions, selection of a subscription package if applicable, entering of payment details, and connection to the user's smart device. These registration steps can later be amended.
Registration may be performed for other members of the same household to use the same device.
The user also registers with the app if the user has any missing teeth, fillings in any of their teeth, implants, prosthetics or any other know conditions. Information about the user's diet and/or health conditions may optionally also be collected.
The image capturing process is now described in greater detail. The app running on the mobile telephone 200 guides the user during the image capturing process. The user is directed to move the transillumination device 100 around one quadrant (i.e. quarter) of the jaw at a time, as described below. Each quadrant is defined between the rearmost tooth to the central front incisor, for the upper and lower jaw and for the left and right sides of each—i.e. there is an upper-left quadrant, a lower-left quadrant, an upper-right quadrant and a lower-right quadrant.
For each quadrant, the user is instructed where to start (e.g. from the rearmost tooth of one of the four quadrants) and accordingly places the head portion 110 of the transillumination device 100 over the rearmost tooth (or other designated starting point) of the selected quadrant and slides it into place so that the central portion 114 is facing the occlusal/incisal surface of the tooth, with the flexible wing portions 116 contacting either side of the tooth. Then the user turns on the image capturing, for example by clicking a button on the device or the app and, under the direction of the app, moves the head portion 110 from tooth to tooth until all teeth in the selected quadrant are imaged. Under the direction of the app, the user briefly pauses (e.g. for 1 to 3 seconds) over each tooth to be imaged so that the head portion 110 is temporarily held stationary relative to the tooth being imaged. Whilst held stationary, different lighting conditions are applied to the tooth (as discussed below), and a plurality of imaged are captured. Each image is sent to the mobile telephone 200 for processing by the app.
Alternatively, the transillumination device may perform a pre-selection of the images, based on image quality, so that only images meeting certain quality criteria are sent to the mobile telephone 200. The quality criteria include one or more of focus/sharpness, acceptable lighting (i.e. not over/under exposed) and the presence of a tooth within the image.
The app comprises an algorithm that detects if a tooth is present within an image. In this algorithm the tooth image is segmented, and shape recognition is used to determine the type of tooth. Together with the given quadrant, and the known sequence of the teeth, the imaged tooth is identified and labelled according to the international standard numbering system. Based on the position of the tooth, and the brightness and the contrast in the image, the app selects the best image for each tooth from the series of images that are captured for that tooth. The selection may be based on quality of the images such as uniformity of lighting, contrast and alignment of the image. When/if the quality of the image is approved (i.e. it meets predetermined criteria such as those outlined above), visual feedback is provided to the user via their smart device to indicate which teeth have successfully been imaged. For example, the corresponding tooth will be marked on the model of the teeth presented on the app (for example, the corresponding tooth may be shaded green), and the user is instructed to move to the next tooth. If no images are approved for one or more teeth because of insufficient quality for analysis, the app indicates to the user that the tooth should be re-imaged.
As an alternative to the user holding the head portion 110 stationary on each tooth to acquire images, the user may sweep the head portion 110 across the quadrant with a slow, continuous sweeping motion. A series of images are taken in the sweep, including images under different lighting conditions for each tooth. If one or more of the teeth is not successfully imaged, the app directs the user to perform the sweep again.
Once an image of each tooth is approved and labelled, the images are then sent from the mobile telephone 200 to the cloud-based server 300. Such images can be anonymised prior to communication and the communication can be end-to-end encrypted to protect a user's privacy. The cloud-based server 300 comprises a machine learning algorithm, which in this case is a deep learning neural network (running on a processor 320) with the capability of identifying caries and categorising the identified caries in transillumination images of the teeth.
The processor 320 returns a user report regarding the status of each tooth (i.e. no caries, or caries, and the classification of caries if they are present) to the mobile telephone 200 and this is displayed to the user as visual feedback on a picture of the arrangement of the teeth (as shown in
The user report generated by the processor 320 is encrypted prior to sending to the mobile telephone 200. The report does not include any information which would allow the user to be identified, i.e. the data is anonymised.
The app displays informative and/or motivational text (for example, “Well done!”) if no caries are identified. If caries code 1 or 2 are identified, helpful information regarding appropriate oral care (for example, “Ensure that you brush for at least two minutes in the morning and the evening”) is displayed to the user.
If any of the caries are identified as code 3, 4 or 5, the user is advised to visit a dentist. The cloud-based server 300 comprises a database of dental clinics, and the app presents a list of such clinics which are local to the user (and/or a map showing the location of these), based on the user's location data or the user selecting a locality. Alternatively such a database may be included in the app or it may be a separate database in its entirety, which can be accessed by the cloud-based server or smart device. The user can choose one or more dental clinics 400a, 400b from this list to be given access to a detailed dental report, so that the dental clinic(s) can provide a treatment plan and/or cost estimate to the user for treatment of the identified caries. The detailed dental report is a standardised report including images of all of the user's teeth captured by the transillumination device 100. The detailed dental report comprises a clickable model of the teeth so that the dental professional can select each individual tooth to see the corresponding transillumination image and labelled caries. The detailed dental report does not include any information which would allow the user to be identified, i.e. the data is anonymised.
The user is also given the option to add an email address for a dental clinic (not already in the database) that they would like to send the report to. A link to download the report is sent to that email address, and the dental clinic would then have to sign up and log in to access to the report.
To facilitate the dental clinics accessing the user's report, as well as sending the user's report to the mobile telephone 200, the processor 320 sends the detailed dental report to a safe server 340. The server is safe in that all communication with the safe server 340 is end-to-end encrypted, and two-step authentication is required to access data from the safe server 340.
When a user chooses one or more dental clinics to be given access to their report, a link is sent from the safe sever 340 to the dental clinic(s) 400a, 400b to enable them to access the report from the safe server 340.
As noted above, communication between the dental clinic(s) 400a, 400b and safe server 340 is end-to-end encrypted, and the dental clinic(s) 400a, 400b are authenticated by two-factor authentication. Once authenticated, the dental clinic is able to download the user's report from the safe server 340.
A dental practitioner at the dental clinic reviews the images and the identified caries, and determines a treatment plan and/or cost estimate and may suggest an appointment time/location. This information is then sent back to the safe server 340. The safe server 340 receives the cost estimate and/or treatment plan and delivers this via the app to the user. The user can then contact a dental clinic 400a, 400b to arrange treatment.
The lighting features of the transillumination device 100 will now be described in greater detail. As noted above, the first and second flexible wing portions 116 each comprise a plurality of LEDs. The LEDs 122 are individually controllable, and each is connected to the controller 180 via the flex PCB 184 in the main body portion 150 (comprising the LED-interface portion 186), the pogo connectors, and the flex PCB 118 in the head portion 110. Because the LEDs 122 are individually controllable, the transillumination device 100 has the capability of illuminating teeth with different sets of LEDs illuminated, so as to create a plurality of different lighting conditions.
Each flexible wing portion 116 is defined by four edges. These are labelled in
Each flexible wing portion 116 comprises four LEDs 122. As shown in
The LEDs are individually controllable (such that each can be turned on or off independently of the status of the others), and this allows for multiple different lighting conditions to be achieved.
In general, at least one LED is illuminated on each side. This is advantageous, but not limiting on the invention. Similarly, it is generally advantageous light is illuminated further from the tip of the tooth (i.e. closer to the gum-line). The camera captures images from near the tip of the tooth, so to image the greatest possible volume of the tooth, and in particular to capture as much as possible of the shadows indicative of caries, it is advantageous to have light entering the tooth further from the tip of the tooth, near the gum-line. If the tooth is illuminated too far from the gum-line, the shadows nearer the gum-line will be hidden.
As discussed above, the LEDs can each be controlled such that each is either on, or off. However, instead of an LED being off, it could instead be illuminated at a reduced intensity.
Whilst eight LEDs 112 have been described above, a greater number of (or fewer) LEDs could instead be provided. Additional lighting conditions would be available for a greater number of LEDs.
Whilst the LEDs described above all have the same nominal spectral characteristics (including the same peak wavelength and peak width), it will be appreciated that one or more of the LEDs could have different spectral characteristics from the others (with peak wavelengths still within the near-IR range) to allow for images to be captured under a plurality of near-IR wavelengths.
The plurality of lighting conditions can be cycled through as the transillumination device 100 is moving over the teeth, so that for each tooth, at least one image is taken under each of the plurality of lighting conditions. At least one of the plurality of lighting conditions should result in the capture of a suitable image for caries analysis, but the particular lighting condition which will achieve this will vary depending on the tooth being imaged. For example, for a molar which has had a filling, a suitable lighting condition could be that all the LEDs 122 should be illuminated. However, when an incisor is imaged under the same lighting condition, it is likely that the resulting image would be over-exposed (because too much light was incident into the tooth). In that case, a suitable lighting condition would include only a subset of the LEDS 122 (i.e. not all of the LEDs 122) begin illuminated. For example, half of the LEDs could be illuminated.
As an alternative to cycling through all lighting conditions for each tooth, the lighting conditions may be applied based on knowledge of the particular tooth that is being imaged, with a predetermined lighting condition being applied for that particular tooth. Knowledge of the particular tooth that is being imaged may be obtained through shape-recognition of the tooth (for example using machine learning techniques and based on geometrical patterns), and/or through knowing the expected sequence of teeth to be imaged, for example. If the resulting image is not acceptable (because the lighting condition does not allow the tooth to be imaged correctly), then a different lighting condition may be applied.
The first lighting condition to be applied to a given tooth may be pre-set based on a prior calibration process carried out by the user on first use of the device. In the calibration process, a plurality of lighting conditions may be sequentially applied to the tooth, and an image may be acquired under each lighting condition. Then, the images are analysed to determine the highest quality image. The lighting condition under which the highest quality image was acquired is then pre-set as the first lighting condition. The highest quality image may for example be one with minimal reflections from stray light, and/or an image with the correct exposure (not overexposed by putting too much light into the tooth, or underexposed by putting too little light into the tooth), and/or an image with appropriate brightness and contrast.
It will be appreciated that rather than using a single captured image, it is possible to capture and select multiple images of the same tooth and use parts of each image, or multiple overlaid images of the same tooth in the trained neural network of the remote server.
For example, it is possible to capture multiple images of a tooth under illumination by near-IR at different wavelengths (for example where one or more LEDs are provided having different wavelength characteristics from the others). The multiple images of the same tooth can then be combined to make a combined image as an input to the machine learning algorithm. Each image of the multiple images in the combined image can be combined with the others with a weighting factor of between 0 and 1, where 0 means no contribution and 1 means complete contribution.
The flexible wing portions 116a and central portion 114 comprise a soft and flexible over-moulding. In this case, a UV-curable elastomer is used for the majority of the over-moulding, with an IR-transparent silicone material being used for the over-moulding over the LEDs 122a. Other materials may be used instead of the UV-curable elastomer; for example a thermoplastic elastomer (TPE) may be used. The central portion 114a of the tip 112a comprises a window (i.e. an aperture) 124a in the over-moulding. The window 124a is configured to face the occlusal/incisal surface of the user's tooth.
The flexible wing portions 116a are flexible to ensure that the LEDs 122a remain close to the tooth in use. The flexible wing portions 116a are configured to flex outwardly slightly when positioned over the tooth, but a returning force acts against this outward flexing, so that the flexible wings 116a grip onto the sides of the tooth. The flexing of the flexible wing portions 116a ensures that there is minimal clearance between each LED 122a and the surface of the tooth; this reduces stray light which could be detrimental to imaging, and also ensures that an appropriate amount of light penetrates into the tooth to allow for imaging.
Each LED 122a is configured to emit near-IR light, having a peak wavelength at approximately 850 nm and a spectral bandwidth of approximately 35 nm. The radiant intensity (at a forward current of 100 mA) is approximately 9 to 18 mW/sr, and typically is around 13 mW/sr. The LEDs 122a may also be configured to emit light in the visible spectrum—this allows a user to visualise that the device is working.
Each flexible wing portion 116a is defined by four edges. These are labelled in
As shown in
That is, the four LEDs 122a on a flexible wing portion 116a sit at the corners of a rhombus/parallelogram. Two sides of the rhombus/parallelogram are parallel to the proximal edge and the distal edge 117d, and the other two sides are non-parallel to the base edge 117a.
At least one LED 122a should be located adjacent to the gum-line when in use, no matter which tooth is being imaged. Here, adjacent to the gum-line means close to, but slightly vertically offset from the gum-line, so that light is still directed into the tooth rather than into the gum. To image the greatest possible volume of the tooth, and in particular to capture as much as possible of the shadows indicative of caries, it is advantageous to have light entering the tooth from near the gum-line. It depends on the tooth as to which of the LEDs 122a is in the best position; on a molar in the lower jaw for example the best-positioned LED 122a may be the one positioned lowermost down the tooth when the head portion is in place on a tooth. On an incisor or canine in the lower jaw, for example, that same LED 122a may be located below the gum-line, in which case it is not best-positioned to illuminate the tooth. In such a case, the best positioned LED 122a may be one located closest to the tip of the tooth when the head portion is in place on the tooth.
The flexible wing portions 116a shown in
The second projection 116c runs from the proximal edge 117c (nearest to the main body portion 150 of the device) to the opposed distal edge 117d (furthest from the main body portion 150 of the device), and is located between the LEDs 122a and the base edge 117a. This second projection 116c should prevent or reduce light from being transmitted directly from the LEDs 122a into the camera. In the embodiment shown, the second projection 116c slopes down towards the base edge 117a in the direction from the distal edge 117d to the proximal edge 117c.
The central portion 114a comprises alignment projections 125a and 125b. The first alignment projection 125a projects away from the central portion 114 and runs across the top of the tip 112a (where the top of the tip is the end of the tip furthest from the main body portion 150). The second alignment projection 125b is broadly parallel to the first alignment projection 125a, but is located the other side of the flexible wing portions 116a than the first alignment projection 125a. The first and second alignment projections therefore bracket the flexible wing portions 116a. The first and second alignment projections are broadly perpendicular to the flexible wing portions 116a. The first and second alignment projections aid the user to hold the device parallel to the row of teeth.
As shown in
Some exemplary lighting conditions (combinations 1 to 10) which can be achieved with such a configuration are listed below. Here, only the groups which are illuminated are mentioned.
The other groups which are not mentioned are not illuminated.
In these combinations, the maximum number of LEDs lit simultaneously is four, but more may be used. Using four or fewer LEDs at any one time reduces the risk of reflection of the LED light, which can be detrimental to image quality.
For a given tooth, a pre-set combination (or combinations) is used. These may be identified in a calibration process carried out by the user where on first usage of the device, all of the combinations will be cycled through for each tooth, and an appropriate condition/conditions will be identified for each tooth. The appropriate combination(s) depends on tooth size (height and thickness) and position.
Combinations 3 to 6 provide light coming from only one side of the teeth. These combinations are particularly suitable for imaging incisors. The light should then be directed from the labial (facial) side of the incisor, through the tooth, and out of the lingual/palatal side of the tooth. This is because the lingual/palatal side of an incisor has a sloping shape, which can create strong reflections of the LED light, leading to poor imaging. The incisors are thinner than other teeth, and images of sufficient quality can be obtained with light coming from only one side. Whether a base group of top group is used for a given tooth depends on the height of the tooth.
Combinations 7 to 9 might be used for example when imaging very large molars, where additional light is needed to obtain images of sufficient quality.
The groups of LEDs can each be controlled such that every LED in a group is either on, or off. However, instead of a group being off, the LEDs within that group could instead be illuminated at a reduced intensity.
Whilst eight LEDs 112a have been described above, a greater number of (or fewer) LEDs could instead be provided.
Whilst the LEDs 122a described above all have the same nominal spectral characteristics (including the same peak wavelength and peak width), it will be appreciated that one or more of the LEDs could have different spectral characteristics from the others (with peak wavelengths still within the near-IR range) to allow for images to be captured under a plurality of near-IR wavelengths.
Rather than using a single captured image, it is possible to capture and select multiple images of the same tooth and use parts of each image, or multiple overlaid images of the same tooth in the trained neural network of the remote server.
For example, it is possible to capture multiple images of a tooth under illumination by near-IR at different wavelengths (for example where one or more LEDs are provided having different wavelength characteristics from the others). The multiple images of the same tooth can then be combined to make a combined image as an input to the machine learning algorithm. Each image of the multiple images in the combined image can be combined with the others with a weighting factor of between 0 and 1, where 0 means no contribution and 1 means complete contribution.
The control scheme identified above (with four groups of two LEDs, operable in some or all of the combinations listed above) is not limited to usage with the tip 112a shown in
The machine learning algorithm is trained on a training set of images comprising 1000 images of each category of caries (category 1 to category 5), as identified by a qualified dentist.
Whilst one configuration for a transillumination device has been described above, other variations are possible. Some possible alternative configurations are described below.
As discussed above, one configuration of the transillumination device comprises a rechargeable battery 172 which is inductively charged by an inductor 174. The inductor 174 sits in the base of the main body portion, and interacts with an external inductive charging station, of the kind known in the art. Similar inductive charging stations are for example commonly used to charge electrical toothbrushes. An alternative configuration is discussed below.
It is advantageous for the transillumination device to be able to communicate wirelessly (via Bluetooth for example) with the user's smart device (e.g. mobile phone) whilst the transillumination device is in use, i.e. being held by the user in their hand. Since water in the user's body (e.g. in their hand/mouth) absorbs Wi-Fi signals (e.g. 2.45 GHz radio waves), it is advantageous to position the Wi-Fi antenna at a position at which the user's hand or mouth does not surround the Wi-Fi antenna. A suitable position is the base of the main body portion of the transillumination device. However, the inductor (comprising ferrite material) forming part of the indicative charging circuit also absorbs Wi-Fi signals (e.g. 2.45 GHz radio waves). For this reason, to allow the Wi-Fi antenna to be positioned in the base, the indicative charging circuit must be moved away from the conventional position in the base.
It will be appreciated that with the inductor 574 located in a middle portion 500a of the device 200, an inductive charging station for charging the device 500 will have to take a different form compared to that previously discussed. For example, the inductive charging station may sit next to or wrap around the middle portion 500a of the device, rather than interacting with the base.
During charging, the coils 602a, 602b are each part of a resonant circuit, the two resonant circuits are loosely magnetically coupled. The coil 602a is arranged to receive energy through inductive coupling with the coil 602b of the charging station. Alternating current passes through the induction coil 602b in the charging station. The moving electric charge from this creates a magnetic field, which fluctuates in strength because the electric current's amplitude is fluctuating. This changing magnetic field, enhanced by the rods 601, creates an alternating electric current in the coil 602a of the device, which in turn passes through a rectifier to convert it to direct current. The direct current is then used to charge the rechargeable battery of the transillumination device.
In the neck portion 705, seen more clearly in
A heater (not shown) is arranged to heat the metal frame 716, which in turn conducts heat to the transparent window 710 and prevents fogging/condensation in use. To do so the window may be heated to 40° C. within 20 seconds, for example. In use, with a tip 800 mounted as shown, transillumination of a tooth is performed and the camera 712 captures images through the transparent window 710. In use the transparent window 710 is exposed to the conditions (heat and humidity) of a user's month.
It will be appreciated that the devices and methods described herein could be adapted for use on the teeth of animals. In such a case, the device would be more robust that a device made for human-use (comprising a stronger casing to withstand chewing by an animal, for example). The user of the device would then be a veterinary professional or possibly the animal's owner. Different sized/shaped head portions 110 for the transillumination device 100 would also be provided, with a size and shape appropriate for use with different animals—for example, dogs, cats and horses. The LEDs 122 and lens/prism arrangements could also be adapted accordingly.
The following clauses set out features of the invention which may not presently be claimed in this application, but which may form the basis for future amendment or a divisional application.
1. A main body portion for a dental examination instrument, the main body portion comprising:
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018550.0 | Nov 2020 | GB | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/083026 | 11/25/2021 | WO |
