IRRADIATION DEVICE AND SYSTEM FOR PHOTODYNAMIC DISINFECTION OF TEETH AND GUMS

Description

[0001] The present invention relates to an irradiation device for photodynamic disinfection of teeth and gums in a mouth. The invention further relates to a system comprising such an irradiation device.

[0002] During photodynamic disinfection of teeth and gums in the mouth, a harmful biofilm, usually formed by bacteria, is destroyed on the teeth and gums through the interaction of light and a photosensitizer (also called a "photosensitizer") in the mouth, thereby combating caries, gingivitis, and / or periodontitis, for example. The photosensitizer penetrates the bacteria or attaches itself to them and is activated by the irradiation. This generates free radicals, such as reactive oxygen species ("ROS"). The free radicals are neither carcinogenic nor genotoxic to humans and act as a biocide, i.e., a substance that destroys pathogens, such as fungi (including their spores), bacteria, parasites, and viruses. Depending on the type of photosensitizer, it acts either as a catalyst during photodynamic disinfection, which generates free radicals from the environment upon exposure, for examplefrom a solution containing the photosensitizer; or the photosensitizer itself releases free radicals upon irradiation. The wavelength of the radiation emitted by the radiation source must be matched to the photosensitizer used and its absorption spectrum; it generally ranges from the ultraviolet to the infrared range.

[0003] US 2015 / 0044628 A1 discloses a device for whitening teeth that has a curved groove and a handle protruding from it. The groove is filled with a photoactivatable substance, e.g., a gel, and pressed over the dental arch of the upper or lower jaw like a dental impression tray. Ultraviolet LEDs are attached to the inner side walls of the groove to irradiate the teeth. One disadvantage is that, due to its size and the gel filling, the groove is perceived as extremely unpleasant in the mouth, often triggering a gag reflex, for example. Multiple grooves of different sizes and / or curvatures must also be provided for different dentitions. Furthermore, the ultraviolet radiation has a localized effect, requiring a large number of LEDs. This prevents the groove from being made smaller and, given that the efficiency of the LEDs decreases with shorter wavelengths, leads to increased waste heat.

[0004] WO 2011 / 084744 A1 describes the use of infrared LEDs for photodynamic disinfection of the mouth. To counteract excessive heating caused by infrared radiation, it is suggested that only specific parts of the mouth be irradiated.

[0005] US 2018 / 0256916 A1 shows an irradiation device for photodynamic oral disinfection with a radiation source located outside the mouth, the radiation of which is guided into the mouth by means of a curved light guide.

[0006] The invention aims to create an irradiation device and a system which are simple, comfortable and efficient to use.

[0007] This object is achieved according to a first aspect of the invention by an irradiation device for the photodynamic disinfection of teeth and gums in a mouth, comprising a mouthpiece which can be inserted into the mouth and which has a U-shape modeled on the dental arch and is equipped with one or more radiation sources for radiation in a wavelength range between 500 nm and 1000 nm, a handle which projects from the mouthpiece in such a way that it protrudes from the mouth after insertion of the mouthpiece, and a controller for controlling the radiation sources, wherein the handle has a heat sink and the radiation sources are applied to a heat-conducting substrate which connects the radiation sources to the heat sink in a heat-conducting manner.

[0008] The invention is based on the discovery that radiation in the wavelength range between 500 nm and 1000 nm is also transmitted through tooth enamel and radiated by it. This results in a less localized radiation effect than, for example, ultraviolet radiation, allowing for a smaller design of the irradiation device, particularly its mouthpiece, and consequently simple and efficient application with the same disinfection effect. To prevent an unpleasant sensation of heat in sensitive teeth due to the heat effect accompanying the radiation, effective heat dissipation via the heat-conducting substrate is provided, making the irradiation particularly safe and comfortable.

[0009] In an advantageous embodiment, the substrate is a metal-core circuit board located in a plane defined by the U-shape. The metal-core circuit board fulfills two functions: it supports and contacts the components and dissipates the heat from the radiation sources. This eliminates the need for a separate heat-conducting substrate, enabling a simple design and a compact size—especially for the nozzle.

[0010] In a particularly preferred variant of this embodiment, the radiation sources are applied to at least one of the top and bottom surfaces of the metal-core circuit board and have radiation directions perpendicular to the aforementioned plane. The mouthpiece can thus be constructed in layers to be particularly flat and space-saving. The radiation is guided through the tooth enamel, starting from the chewing surface of the molars or the cutting edge of the incisors, along each tooth and into the gingival groove between the tooth and gum, and radiated, resulting in uniform, comprehensive, and deep disinfection. Furthermore, one and the same flat mouthpiece can be used for a wide variety of dentition variations.

[0011] The radiation sources can be any radiation source or the ends of waveguides fed with corresponding radiation. Infrared LEDs are particularly advantageous. These are efficient and available for various infrared wavelength ranges, making it easy to match the photosensitizer(s) used. Furthermore, infrared radiation also has a wound-healing and anti-inflammatory effect ("photobiological effect"). The infrared LEDs can, for example, be LEDs for water-filtered infrared-A ("wIRA LEDs").

[0012] The mouthpiece is coated with a transparent coating, at least in the wavelength range of the radiation sources. This increases the service life and safety of the mouthpiece and protects the teeth. Suitable coatings are durable, lightfast, saliva- and abrasion-resistant, non-toxic, and easy to apply, e.g., by injection. Examples of such coatings are well known in medicine, especially dentistry.

[0013] Furthermore, the coating over each radiation source is shaped into a radiation-refracting lens. This allows the radiation to be directed and achieves uniform irradiation of the entire mouth, or rather the teeth and gums, with only a few radiation sources.

[0014] It is advantageous if the control unit is located in the handle. This facilitates handling, as no wired or wireless connection to the control unit is required during use of the irradiation device. The irradiation device can thus be constructed as a space-saving integrated unit.

[0015] It is particularly pleasant for the user and effective in use if the control system is designed to control the radiation sources to emit radiation with a radiation intensity that changes over time.

[0016] A particularly efficient variant results when the mouthpiece has at least two radiation sources and the control is designed to control the at least two radiation sources to emit radiation intensities that differ from one another.

[0017] In a favorable embodiment, the irradiation device has a groove running along the U-shape on the top and bottom of the mouthpiece, and a mouthguard that is removably inserted into the groove and is transparent at least in the wavelength range of the radiation sources. This prevents direct biting on sensitive parts of the mouthpiece or its coating, thus protecting the device and making its use even safer.

[0018] It's particularly advantageous if the mouthguard is made of silicone. Silicone is soft and therefore particularly comfortable to use. When the silicone mouthguard is bitten, the mouthpiece and the entire irradiation device remain consistently secure in the mouth. Furthermore, the soft and transparent silicone improves the transmission of radiation into the tooth enamel, increasing the effectiveness of the irradiation.

[0019] In order to provide the most even, anatomically favorable tooth support possible, the mouthguard is preferably thicker in the middle of the U-shape than at the ends of the U-shape.

[0020] According to a second aspect, the invention provides a system for photodynamic disinfection of teeth and gums in a mouth, which is characterized by an irradiation device of the aforementioned type and a rinsing solution for rinsing the mouth in preparation for irradiation, which rinsing solution contains at least one photosensitizer. When rinsing the mouth with the rinsing solution before irradiation, the photosensitizer infiltrates the bacteria of the biofilm and remains in the mouth during irradiation, without the entire rinsing solution used during rinsing having to be retained in the mouth. With regard to further advantages and embodiments of the system, reference is made to the preceding explanations regarding the irradiation device.

[0021] In addition to the photosensitizer, the rinsing solution can contain various additives that enhance the disinfection effect or achieve additional effects. In a particularly advantageous embodiment, the rinsing solution contains a nanoparticle carrier to which the photosensitizer is bound. It is particularly advantageous if the nanoparticle carrier is a graphene-based nanoparticle carrier or chitosan. Such nanoparticle carriers significantly improve the uptake of the photosensitizer into the biofilm, which leads to an increased disinfection effect. Furthermore, nanoparticle carriers improve the long-term effectiveness of the disinfection, prevent a decline in bacterial sensitivity, and reduce possible solubility problems with certain photosensitizers, thus broadening the range of applicable photosensitizers.

[0022] It is advantageous if the rinsing solution contains potassium iodide and / or urea. Potassium iodide and urea each enhance the antimicrobial photodynamic effect of the rinsing solution. It is also advantageous if the rinsing solution contains L-arginine. This amino acid acts as a biofilm disruptor and thus also enhances the effect of the photosensitizer on the biofilm. It is particularly beneficial if the rinsing solution contains xylitol. Xylitol blocks the metabolism of the biofilm and thus further prevents new biofilm formation. It is also advantageous if the rinsing solution contains a nuclease, e.g., an RNase or DNase. This supports the degradation of bacteria in the biofilm compromised by the photodynamic effect.

[0023] The invention is explained in more detail below with reference to an embodiment illustrated in the accompanying drawings. Fig. 1 an irradiation device according to the invention in its position inserted into a mouth in a vertical longitudinal section; Fig. 2 section A of Fig. 1 ; Fig. 3 the irradiation device of Fig. 1 in a perspective view from above; and Fig. 4 the irradiation device of Fig. 1 in the top view.

[0024] Fig. 1 shows an irradiation device 1 for the photodynamic disinfection of teeth 2 (here: upper and lower incisors 2 1 , 2 2 ) and gums 3 in a mouth 4, which is shown in detail with a tongue 5, an upper and a lower lip 6 1 , 6 2 . A substantially bacterial biofilm 7 has formed on the lower incisor 2 2 . Biofilm 7 has also been deposited on the gum 3 surrounding the lower incisor 2 2 and in a gingival groove 8 between the lower incisor 2 2 and the gum 3. Such a biofilm 7 is harmful to teeth 2 1 , 2 2 and gums 3 because it causes, among other things, caries, gingivitis and / or periodontitis. In comparison, the upper incisor 2 1 and the surrounding gingiva 3 are free of biofilm 7. The harmful biofilm 7 is to be destroyed by photodynamic disinfection, as described below.

[0025] During photodynamic disinfection, a photosensitizer is introduced into the mouth 4. Subsequent irradiation activates the photosensitizer, generating free radicals, e.g., reactive oxygen species ("ROS"), which act as a biocide to destroy the biofilm 7 and thereby disinfect the teeth 2 and gums 3. Most photosensitizers act as catalysts, generating free radicals from the environment upon irradiation; other photosensitizers themselves release free radicals upon irradiation.

[0026] In the present case, the photosensitizer 9 ( Fig. 2 ) as required, e.g., indocyanine green, methylene blue, toluidine blue, rose bengal, erythrosine, acridine orange, and / or the additional antibiotic tetracycline. The photosensitizer 9 is contained in a rinsing solution with which the user rinses his mouth 4 for a few seconds (e.g., approximately 30 seconds) in preparation for the subsequent irradiation. Thus, the irradiation device 1 and the rinsing solution containing the photosensitizer 9 interact as a system. It is understood that more than one photosensitizer 9 may be contained in the rinsing solution.

[0027] The rinsing solution is, for example, water-based with optionally a small proportion (e.g., between 0.5 and 1.5 wt.%, in particular 0.9 wt.%) of dissolved sodium chloride. During rinsing, the photosensitizer 9 attaches to the biofilm 7 and / or infiltrates the bacteria of the biofilm 7. Optionally, the rinsing solution contains a nanoparticle carrier, e.g., a graphene-based nanoparticle carrier, chitosan, etc., to which the photosensitizer is bound and which is readily absorbed by the cells of the biofilm 7.

[0028] The rinsing solution may further optionally contain bactericides and / or oxygenators, etc. In particular, the rinsing solution optionally contains potassium iodide, urea, stannous fluoride and / or amine fluoride to enhance the antimicrobial effect, L-arginine and / or methyl salicylate as a biofilm disruptor, xylitol to block the metabolism of the biofilm, a nuclease (e.g. an RNase or DNase) to improve the degradation of bacteria in the biofilm compromised by the photodynamic effect, zinc chloride to facilitate the removal of hard deposits, particularly on the teeth 2, sodium fluoride to strengthen the tooth enamel and / or flavonoids or catechins with antioxidant effects.

[0029] According to Fig. 1 The irradiation device 1 comprises a mouthpiece 10, which is inserted into the mouth 4, and a handle 11 projecting from the mouthpiece 10, which protrudes from the mouth 4 when the mouthpiece 10 is inserted into the mouth 4. The mouthpiece 10 is equipped with one or more radiation sources 12 for radiation 13 in a wavelength range between 500 nm and 1000 nm, i.e., the emitted radiation 13 lies, depending on the selected type of radiation source 13, in a certain wavelength range and has a pronounced intensity maximum between 500 nm and 1000 nm. The radiation sources 12 serve to irradiate the biofilm 7 infiltrated with photosensitizer 9 or the biofilm 7 with attached photosensitizer 9 and thus contribute beyond the photodynamic effect - more or less strongly depending on the wavelength - to the photobiological effect, i.e.to wound healing and inflammation inhibition in the gums 3, and thus to the prevention of periodontitis. The irradiation device 1 further has a controller 14, which controls the radiation sources 12 and, in the example shown, is arranged in the handle 11, but could alternatively be separate and connected, for example, via a cable to the radiation sources 12, or even arranged in the mouthpiece 10.

[0030] The handle 11 has a heat sink 15. In the embodiment of Fig. 1 The heat sink 15 is a cooling fin on the end of the handle 11 facing away from the mouthpiece 10. In other embodiments, the heat sink 15 can, for example, have a set of cooling fins or be part of the housing surface of the handle 11 and be cooled passively, e.g., by convection. Alternatively, the heat sink can be actively cooled, e.g., with a fan or a Peltier element.

[0031] The radiation sources 12 are applied to a thermally conductive substrate 16. The thermally conductive substrate 16 connects the radiation sources 12 of the mouthpiece 10 to the heat sink 15 of the handle 11 in a thermally conductive manner and thus extends from the mouthpiece 10 into the handle 11.

[0032] As in Fig. 3 As shown, the mouthpiece 10 has a U-shape 17, which is modeled after the dental arch, e.g., an average dental arch. The U-shape 17 defines a plane ε, which, when the mouthpiece 10 is inserted into the mouth 4, lies between the teeth 21 of the upper jaw on the one hand and the teeth 22 of the lower jaw on the other.

[0033] In the illustrated example, the heat-conducting substrate 16 is a metal-core circuit board lying in the plane ε, e.g., with an aluminum or copper core. It is understood that the substrate 16 does not have to be completely flat, but may, for example, have one or more bends, for example, at the transition from the mouthpiece 10 to the handle 11 and / or within the handle 11. Alternatively, the substrate 16 could have any shape or even be a heat pipe.

[0034] As in Fig. 2 As shown, the radiation sources (e.g. LEDs, here: infrared LEDs, for example LEDs for water-filtered infrared-A, "wIRA-LEDs") 12 are optionally applied both to the top side 16 1 and to the bottom side 16 2 of the metal-core circuit board and in each case have radiation directions σ that are approximately normal to the said plane ε. In the present context, a radiation direction σ that is normal to the plane ε refers to radiation 13 emitted by a radiation source 12 at the usual divergence and which is on average directed normal to the plane ε. Different numbers of radiation sources 12 can be applied to the top and bottom sides 16 1 , 16 2 . Alternatively, the one or more radiation sources 12 could be applied only to the top side 16 1 or only to the bottom side 16 2 . Instead of (infrared) LEDs, the radiation sources 12 can be of other types, e.g. conventional (infrared) lamps.Furthermore, ends of waveguides fed with the radiation 13 can form the radiation sources 12.

[0035] Each radiation source 12 preferably has a power density between 0.5 J / cm 2 and 1000 J / cm 2 . The wavelength of the radiation 13 emitted by each radiation source 12 is in the range of approximately 500 to 1000 nm, preferably in the red light or near-infrared ("NIR") range between 610 and 850 nm, and is matched to the photosensitizer 9, i.e., to its absorption wavelength. Conversely, the photosensitizer 9 is selected depending on the wavelength of the radiation 13 emitted by the radiation source 12. For example, indocyanine green becomes active upon irradiation below a wavelength of approximately 810 nm, methylene blue at approximately 650 nm, toluidine blue at approximately 630 nm, rose bengal at approximately 562 nm, erythrosine at approximately 530 nm, acridine orange at approximately 502 nm, etc.

[0036] In the example shown, the Fig. 1 bis 4 the mouthpiece 10 is covered by a coating 18, i.e. completely covered, which protects the sensitive parts of the mouthpiece 10 from saliva and aggressive substances as well as from mechanical wear. Conversely, the coating 18 protects teeth 2, tongue 5 and lips 6 1 , 6 2 from damage or injury caused, for example, by sharp-edged parts of the mouthpiece 10. The coating 18 is transparent at least in the wavelength range of the intensity maximum of the radiation 13 emitted by the radiation sources 12, i.e. in the wavelength range of the radiation sources 12, and is, for example, sprayed onto the mouthpiece 10 or cast therewith. Coatings 18 of this type are known to those skilled in the field of medicine, in particular dentistry.

[0037] The coating 18 is formed over each radiation source 12, i.e., in the radiation direction σ of each radiation source 12, into a lens 19 that refracts the radiation 13. The lens 19 is curved convexly or concavely as required in order to distribute the radiation 13 according to a predetermined pattern—e.g., evenly—over the teeth 2 and the gums 3 in the mouth 4. Alternatively, the lens 19 could be formed by other means, i.e., not by the coating 18 itself, or could be omitted altogether.

[0038] The controller 14 is optionally configured to control the radiation sources 12 to emit radiation with temporally varying intensity, e.g., pulsating or rising and falling. The temporally varying radiation intensity follows a predetermined cycle and enables high peak intensity with simultaneously lower average heat development in the mouth 4. The total irradiation time is between 100 ms and 60 minutes, e.g., approximately 2 to 5 minutes.

[0039] Additionally or alternatively, if the mouthpiece 10 has at least two radiation sources 12, the control 14 can optionally control the radiation sources 12 to emit radiation intensities that differ from one another. In the example of the Fig. 1 For example, the control unit 14 could control the radiation source 12 directed at the lower incisor 2 2 to emit a high radiation intensity, since harmful biofilm 7 has formed on and around the lower incisor 2 2, whereas the control unit 14 controls the radiation source 12 directed at the upper incisor 2 1 free of biofilm 7 to emit a low radiation intensity (here: e.g. no radiation 13 at all).

[0040] In the example of Fig. 3 The mouthpiece 10 has a groove 20 on its top and bottom, which runs along the U-shape 17 of the mouthpiece 10. A mouthguard 21 can be inserted into the groove 20. The mouthguard 21 is transparent at least in the wavelength range of the radiation sources 12 and is optionally replaceable, i.e. it can be removed again after being inserted into the groove 20. The mouthguard 21 serves to protect the teeth 2 or the mouthpiece 10, for example if the mouthpiece 10 is bitten during irradiation. For this purpose, the mouthguard 21 is optionally soft, e.g. made of silicone.

[0041] In order to give the mouthpiece 10 an anatomically suitable shape, the mouthpiece 10 itself and / or the mouthguard 21 is optionally thicker in the middle 17 M of the U-shape 17 than at the ends 17 E of the U-shape 17. The ends 17 E of the U-shape 17 are in the example of the Fig. 3closed with optional caps 22. Furthermore, to better close the mouth 4 when the mouthpiece 10 is inserted, the handle 11 optionally has recesses 23 on the top and / or bottom adjacent to the mouthpiece 10.

[0042] The invention is not limited to the embodiment shown, but includes all variants, modifications and combinations thereof that fall within the scope of the appended claims.

Claims

1. An irradiation device for photodynamic disinfection of teeth (2) and gums (3) in a mouth (4), comprising a mouthpiece (10) which can be inserted into the mouth (4), has a U-shape (17) approximating the dental arch and is equipped with one or more radiation sources (12) for radiation (13) in a wavelength range between 500 nm and 1000 nm, a handle piece (11) which projects from the mouthpiece (10) in such a way that it protrudes from the mouth (4) after insertion of the mouthpiece (10), and a controller (14) for actuating the radiation sources (12), wherein the handle piece (11) has a heat sink (15) and the radiation sources (12) are mounted on a heat-conducting substrate (16) which connects the radiation sources (12) to the heat sink (15) in a heat-conducting manner, and wherein the mouthpiece (10) is covered by a coating (18) which is transparent at least in the wavelength range of the radiation sources (12), characterised in that, above each radiation source (12), the coating (18) is formed into a lens (19) refracting the radiation (13).

2. The irradiation device according to claim 1, characterised in that the substrate (16) is a metal-core printed circuit board lying in a plane (ε) spanned by the U-shape (17).

3. The irradiation device according to claim 2, characterised in that the radiation sources (12) are mounted on at least one of the upper and lower sides (161, 162) of the metal-core printed circuit board and have radiation directions (σ) normal to said plane (ε).

4. The irradiation device according to any one of claims 1 to 3, characterised in that the radiation sources (12) are infrared LEDs.

5. The irradiation device according to any one of claims 1 to 4, characterised in that the controller (14) is arranged in the handle piece (11).

6. The irradiation device according to any one of claims 1 to 5, characterised in that the controller (14) is configured to actuate the radiation sources (12) for emitting radiation of a temporally changing radiation intensity.

7. The irradiation device according to any one of claims 1 to 6, characterised in that the mouthpiece (10) has at least two radiation sources (12) and the controller (14) is configured to actuate the at least two radiation sources (12) for emitting radiation having radiation intensities that are different from each other.

8. The irradiation device according to any one of claims 1 to 7, characterised by a groove (20) running along the U-shape (17) on the upper and lower sides of the mouthpiece (10) and by a tooth protection plate (21) which is removably inserted into the groove (20) and which is transparent at least in the wavelength range of the radiation sources (12).

9. The irradiation device according to claim 8, characterised in that the tooth protection plate (21) is made of silicone.

10. The irradiation device according to claim 8 or 9, characterised in that the tooth protection plate (21) is thicker in the middle portion of the U-shape (17) than at the end portions of the U-shape (17).

11. A system for photodynamic disinfection of teeth (2) and gums (3) in a mouth (4), characterised by an irradiation device (1) according to any one of claims 1 to 10 and a rinsing solution for rinsing the mouth in preparation for irradiation, which rinsing solution contains at least one photosensitiser (9).

12. The system according to claim 11, characterised in that the rinsing solution contains a nanoparticle carrier, preferably a graphene-based nanoparticle carrier or chitosan, to which the photosensitiser (9) is bound.

13. The system according to claim 11 or 12, characterised in that the rinsing solution contains potassium iodide and / or urea.

14. The system according to any one of claims 11 to 13, characterised in that the rinsing solution contains L-arginine, xylitol and / or a nuclease.