Teeth Whitening System

Abstract

The present invention relates to a tooth whitening system (10), comprising a light source (30), a light detector (40) and a processing unit (50). The light source is configured so that the wavelength of the emitted light can be adjusted within an operating wavelength range. The detector is configured to detect the light emitted by the light source. The processing unit is configured to control the light source to adjust the wavelength of the light emitted by the light source, and to determine an absorption measure of the detected light emitted from the light source when adjusting the wavelength. The processing unit is configured to operate the light source at a wavelength at an absorption peak using the determined absorption measure.

Description

Technical Field

[0001] The invention relates to a teeth whitening system, a control method of the teeth whitening system, a computer program element and a computer readable medium. Background Art

[0002] Blue light absorbed by staining molecules inside teeth can be used in combination with hydrogen peroxide (H2O2) to promote tooth whitening.

[0003] Tooth color is primarily caused by staining molecules, which accumulate throughout the tooth structure throughout a person's lifetime. Generally, stains can be classified as intrinsic, non-intrinsic, or internalized, as shown in the table below.

[0004]

[0005]

[0006] Blue light absorbed by the staining molecules inside the teeth improves the whitening effect by promoting the reaction between hydrogen peroxide (H2O2) and the staining molecules. The system for tooth whitening has an oral device, also called a body, placed around the teeth, in which the wavelength (~460nm) and irradiance (25 to 100mW / cm 2 ) to direct uniform illumination onto the teeth.

[0007] Although blue light (400 to 495 nm) can be absorbed by staining molecules inside teeth and improve whitening results by promoting the reaction between hydrogen peroxide (H2O2) and staining molecules, it has been found that different users' teeth have different stain profiles and teeth whitening results may be inconsistent and non-optimized.

[0008] These problems need to be solved urgently. Summary of the invention

[0009] It would be advantageous to have an improved way of whitening teeth. The objects of the invention are solved by the subject matter of the independent claims, wherein further embodiments are incorporated in the dependent claims. It should be noted that the aspects and examples of the invention described below also apply to a teeth whitening system, a control method of a teeth whitening system, as well as a computer program element and a computer readable medium.

[0010] In a first aspect, a teeth whitening system is provided, comprising:

[0011] light source;

[0012] a light detector; and

[0013] Processing unit.

[0014] The light source is configured so that the wavelength of the emitted light can be adjusted within an operating wavelength range. The detector is configured to detect the light emitted by the light source. The processing unit is configured to control the light source to adjust the wavelength of the light emitted by the light source, and is configured to determine absorption metrics at different wavelengths based on the detected light at different wavelengths. The processing unit is configured to operate the light source at a wavelength at an absorption peak using the determined absorption metrics.

[0015] In other words, based on feedback about the types of staining molecules inside the tooth, a tunable wavelength of incident light on the tooth is provided to improve whitening efficacy and consistency.

[0016] In other words, the processing unit is configured to control the light source to scan the wavelength of light emitted over a wavelength range, and determine an associated absorption metric when the wavelength of light emitted by the light source is scanned over the wavelength range, and then operate in a teeth whitening mode at a wavelength at an absorption peak based on the absorption metric.

[0017] In this way, a teeth whitening system using light and, for example, hydrogen peroxide can automatically operate at the correct wavelength for the stains present for a particular user, without having to know what wavelength the system is operating at. Also, once used and the teeth have been whitened with respect to a particular stain, further uses of the system will automatically target the next most prevalent stain.

[0018] Thus, the system can scan the wavelength of light emitted by the light source without knowing what that wavelength is, and then operate at the scan position associated with the absorption peak to automatically target the most prevalent stains present.

[0019] In one example, the processing unit is configured to control the light source to adjust the wavelength of light emitted by the light source within an operating wavelength range of at least 400 to 495 nm.

[0020] In this way, key tooth stains such as carotene, tannic acid (coffee, tea), porphyrin and fluoride stains can be targeted.

[0021] In one example, the system includes at least one additional light source. The processing unit is configured to operate the at least one additional light source at a wavelength at an absorption peak based on the absorption metric.

[0022] In other words, the system can scan the wavelength of light emitted by the first source without knowing what the wavelength is, and then operate the first light source at the scan position associated with the absorption peak, so that the light source is automatically aimed at the most common stains present. However, this information can be used to operate other light sources of the same wavelength, also without knowing the wavelength. For example, the light sources can all be of the same type and are known to emit the same wavelength when driven in a specific way. Therefore, the other light sources only need to match their operating characteristics with the first light source, and can then operate at the same wavelength as the first light source and aim at the most common stains present on the teeth of the person. Therefore, one or more other light sources can be placed at different locations around the subject to aim different teeth at the teeth aimed at by the first light source. One of the other light sources can also be placed adjacent to the first light source to provide a simple way to determine the absorption peak of one light source, and then operate at a higher power by operating more than one light source at that location. Obviously, there can be more than one light source at each location around the subject to target specific teeth with higher power that can only be obtained from one light source.

[0023] In one example, the processing unit is configured to operate at a wavelength scan position associated with a maximum metric in the determined absorption metrics.

[0024] In one example, the processing unit is configured to operate at an absorption peak wavelength, including comparing absorption metrics at different wavelengths of light emitted by the light source to one or more known absorption curves of stain molecules.

[0025] In other words, the determined absorption curve can be compared to known absorption spectra of different molecules to determine the stain type or combination of stain types (or percentage of stain types in the case of multiple stains), thereby facilitating operation of the system at the optimal wavelength.

[0026] In one example, the light source is configured to operate within a range of optical emission powers. The processing unit is configured to control the light source to operate within a range of optical emission powers based on the determined absorption metric.

[0027] Thus, the power of the emitted light can be optimized to provide effective teeth whitening.

[0028] In one example, the processing unit is configured to control the light source to operate the optical power operation so that the intensity of the absorbed light is equal to the required absorption intensity.

[0029] In one example, the light source and the detector are housed in the body such that when the body is placed adjacent to at least one tooth of a user, the light source and the detector are located on opposite sides of the at least one tooth of the user.

[0030] In one example, the light source and the detector are housed in the body such that when the body is placed adjacent to at least one tooth of a user, the light source and the detector are located on the same side of the at least one tooth of the user.

[0031] In a second aspect, a teeth whitening system is provided, comprising:

[0032] Multiple light sources;

[0033] a plurality of light detectors; and

[0034] Processing unit.

[0035] Each light source is paired with a detector. Each light source is configured so that the wavelength of the emitted light can be adjusted within an operating wavelength range. Each detector is configured to detect light emitted from the paired light source. For each light source and detector pair, the processing unit is configured to control each light source to adjust the wavelength of the light emitted by the light source, and determine absorption metrics of different wavelengths based on the detected light of different wavelengths. For each light source and detector pair, the processing unit is configured to operate the light source in each light source and detector pair at a wavelength at an absorption peak using the determined absorption metric.

[0036] In this way, different teeth with different stains can be treated in a customized manner to ensure that all teeth are effectively whitened.

[0037] In other words, the processing unit is configured to control a light source in the light source and detector pair to scan the wavelength of light emitted over a wavelength range, and wherein the processing unit is configured to determine an associated absorption metric when scanning the wavelength of light emitted by the light source over the wavelength range, and wherein the processing unit is configured to operate in a teeth whitening mode for the light source and detector pair at a wavelength at an absorption peak based on the absorption metric when scanning the wavelength of light emitted by the light source over the wavelength range. Thus, the light source(s) for teeth whitening are operated at an optimal wavelength.

[0038] In one example, the processing unit is configured to control each light source to operate at a wavelength that is independent of an operating wavelength of any other light source.

[0039] In a third aspect, a control method of a teeth whitening system is provided. The teeth whitening system includes a light source, a light detector, and a processing unit. The light source is configured so that the wavelength of the emitted light can be adjusted within an operating wavelength range. The detector is configured to detect the light emitted by the light source. The method includes:

[0040] a) the processing unit controls the light source to adjust the wavelength of light emitted by the light source;

[0041] b) a processing unit determining absorption measures at different wavelengths based on the detected light at different wavelengths; and

[0042] c) The processing unit operates the light source at a wavelength at the absorption peak using the determined absorption measure.

[0043] In one example, the system includes at least one further light source, and the method includes the processing unit controlling the at least one further light source to operate at a wavelength at an absorption peak based on the absorption metric.

[0044] In one example, the method includes operating a processing unit at a wavelength scan position associated with a maximum metric in the determined absorption metric.

[0045] According to another aspect, a computer program element for controlling one or more systems as described above is provided, which, when executed by a processing unit, is adapted to perform one or more of the methods described above.

[0046] According to another aspect, a computer readable medium storing the above-mentioned computer element is provided.

[0047] The computer program element may be, for example, a software program, but may also be an FPGA, a PLD or any other suitable digital device.

[0048] In one example, the computer program element may be controlled by a smartphone application, which may optionally display the progress of each treatment (eg tooth shade change).

[0049] Advantageously, the benefits provided by any of the above aspects apply equally to all other aspects, and vice versa.

[0050] The above aspects and examples will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Exemplary embodiments will be described below with reference to the following drawings:

[0052] Figure 1 A schematic setup of an example of a teeth whitening system is shown;

[0053] Figure 2 A schematic setup of an example of a teeth whitening system is shown;

[0054] Figure 3 A method of controlling a teeth whitening system is shown;

[0055] Figure 4 Absorption and transmission spectra of common stains found in teeth, including carotene, tannin, porphyrin, and fluoride stains, are shown;

[0056] Figure 5 Typical scattering coefficients for bovine incisors and human premolars;

[0057] Figure 6 shows a schematic diagram of a transmission measurement, where the absorption coefficient of the tooth can be derived based on Beer-Lambert's law after subtracting this effect from the surface reflection and scattering;

[0058] Figure 7 A schematic diagram of diffuse reflectance measurement is shown, in which the ratio of tooth absorption coefficients at different wavelengths can be derived based on the Kubelka-munk (K-M) model.

[0059] Figure 8 A schematic setup of an example of a teeth whitening system is shown;

[0060] Fig. 9 An example layout of a teeth whitening system is shown;

[0061] Fig.10 A schematic setup of an example of a teeth whitening system is shown;

[0062] Fig.11 A schematic setup of an example of a teeth whitening system is shown;

[0063] Fig.12 A schematic setup of an example of a teeth whitening system is shown;

[0064] Fig.13 A schematic setup of an example of a teeth whitening system is shown;

[0065] Fig.14 A schematic setup of an example of a teeth whitening system is shown;

[0066] Fig.15 A schematic setup showing an example of a teeth whitening system; and

[0067] Fig.16 A schematic setup of an example of a teeth whitening system is shown. DETAILED DESCRIPTION

[0068] Figure 1 A teeth whitening system 10 is shown, comprising a light source 30, a light detector 40, and a processing unit 50. The light source is configured so that the wavelength of the emitted light can be adjusted within an operating wavelength range. The detector is configured to detect the light emitted by the light source. The processing unit is configured to control the light source to adjust the wavelength of the light emitted by the light source to a plurality of different wavelengths, and determine the absorption metrics of the different wavelengths based on the detected light of the different wavelengths. The processing unit is configured to operate the light source at a wavelength at an absorption peak using the determined absorption metrics.

[0069] The light source and the detector may be housed in a body, and the body may be configured to be placed adjacent to at least one tooth of a user.

[0070] Thus, the light source may be configured to emit light that may be transmitted and / or reflected and / or scattered from at least one tooth of a user.

[0071] Thus, the detector may be configured to detect light emitted by the light source that is transmitted and / or reflected and / or scattered from at least one tooth of the user.

[0072] Therefore, the processing unit can be configured to control the light source to adjust the wavelength of light emitted by the light source, and determine the absorption measurement of at least one user's tooth at different wavelengths based on the detected light emitted from the light source and transmitted and / or reflected and / or scattered from at least one user's tooth when the wavelength is adjusted for different wavelengths.

[0073] The processing unit may then utilize the determined absorption metric to operate the light source in a teeth whitening mode at a wavelength at an absorption peak of at least one of the user's teeth.

[0074] In one example, the light source and the detector are housed in a body, wherein the light source and the detector are separated by a fixed and known distance.

[0075] In one example, the light source is a tunable laser.

[0076] In one example, the light source is a tunable LED.

[0077] In one example, a tunable bandpass filter is associated with the light source to change the wavelength.

[0078] In one example, the bandwidth of the light source is less than 5 nm.

[0079] In one example, the bandwidth of the light source is 5 nm.

[0080] In one example, the bandwidth of the light source is 10 nm.

[0081] In one example, the bandwidth of the light source is 15 nm.

[0082] In one example, the bandwidth of the light source is 20 nm.

[0083] In one example, the bandwidth of the light source is 30 nm.

[0084] According to an example, the processing unit is configured to control the light source to adjust the wavelength of light emitted by the light source within an operating wavelength range of at least 400 nm to 495 nm.

[0085] According to one example, the system comprises at least one further light source. The processing unit is configured to operate the at least one further light source at a wavelength at an absorption peak based on the absorption metric.

[0086] Thus, the processing unit may operate the at least one further light source in a teeth whitening mode at the wavelength of the absorption peak based on the absorption metric.

[0087] According to one example, the processing unit is configured to operate in the teeth whitening mode at a wavelength scan position associated with a maximum metric in the determined absorption metrics.

[0088] Thus, the processing unit may operate in a teeth whitening mode at the scanning position associated with the maximum of the determined absorption metrics.

[0089] According to one example, the processing unit is configured to operate at an absorption peak wavelength, including comparing an absorption measure when scanning the wavelength of light emitted by the light source over a wavelength range to one or more known absorption curves of stain molecules.

[0090] Thus, by comparing the absorption measure when the wavelength of light emitted by the light source is swept across a range of wavelengths to one or more known absorption curves of tooth stain molecules, the processing unit may be operated in a teeth whitening mode at the wavelength at the absorption peak.

[0091] According to an example, the light source is configured to operate within a range of light emission powers. The processing unit is configured to control the light source to operate within a range of light emission powers based on the determined absorption metric.

[0092] Therefore, the processing unit may control the light source to operate the light power in the teeth whitening mode based on the determined absorption metric.

[0093] According to an example, the processing unit is configured to control the light source to operate the optical power operation such that the intensity of the absorbed light is equal to the required absorption intensity.

[0094] Therefore, the processing unit may control the light source to operate the light power operation such that the intensity of light absorbed by at least one tooth of the user is equal to the required absorption intensity.

[0095] In one example, a calibration tooth is used to determine the required absorption strength.

[0096] According to one example, the light source and the detector are housed in the body such that when the body is placed adjacent to at least one tooth of a user, the light source and the detector are located on opposite sides of the at least one tooth of the user.

[0097] According to one example, the light source and the detector are housed in the body such that when the body is placed adjacent to at least one tooth of a user, the light source and the detector are located on the same side of the at least one tooth of the user.

[0098] Figure 2An example of a teeth whitening system 100 is shown, including a plurality of light sources 120, a plurality of light detectors 130, and a processing unit 140. Each light source is paired with a detector. Each light source is configured so that the wavelength of the emitted light can be adjusted within an operating wavelength range. Each detector is configured to detect light emitted from the paired light source. For each light source and detector pair, the processing unit is configured to control each light source to adjust the wavelength of the light emitted by the light source to a plurality of different wavelengths, and is configured to determine an absorption metric based on the detected light of different wavelengths. For each light source and detector pair, the processing unit is configured to operate the light source in each light source and detector pair at a wavelength at an absorption peak using the determined absorption metric.

[0099] The plurality of light sources and the plurality of detectors may be housed in a body 110 that is configured to be placed adjacent to a plurality of teeth of a user.

[0100] Each light source may be configured to emit light that may be transmitted and / or reflected and / or scattered from at least one tooth of a user.

[0101] Thus, each detector may be used to detect light emitted by a paired light source that is transmitted and / or reflected and / or scattered from at least one tooth of a user.

[0102] Thus, for each light source and detector pair, the processing unit can be used to control each light source to adjust the wavelength of light emitted by the light source, and determine absorption metrics of one or more of the multiple user teeth at different wavelengths based on the detected light emitted from the light source and transmitted and / or reflected and / or scattered from one or more of the multiple user teeth when the wavelength is adjusted for different wavelengths.

[0103] Thus, for each light source and detector pair, the processing unit may utilize the determined absorption metric to operate the light source in each light source and detector pair in a teeth whitening mode at a wavelength at an absorption peak for one or more of the plurality of user teeth.

[0104] According to an example, the processing unit is configured to control each light source to operate at a wavelength independent of an operating wavelength of any other light source.

[0105] Thus, the processing unit may control each light source to operate in a teeth whitening mode at a wavelength that is independent of the operating wavelength of any other light source.

[0106] In one example, the processing unit is configured to control each light source to adjust the wavelength of light emitted by the light source within an operating wavelength range of at least 400 nm to 495 nm.

[0107] In one example, the processing unit is configured to operate at a scanning position associated with a maximum metric among the determined absorption metrics.

[0108] Thus, the processing unit may operate in a teeth whitening mode at the scanning position associated with the maximum of the determined absorption metrics.

[0109] In one example, the processing unit is configured to operate at an absorption peak wavelength, including comparing an absorption metric when scanning the wavelength of light emitted by the light source over a range of wavelengths to one or more known absorption curves for stain molecules.

[0110] Thus, by comparing the absorption measure when the wavelength of light emitted by the light source is swept across a range of wavelengths to one or more known absorption curves for stain molecules, the processing unit may be operated in a teeth whitening mode at the wavelength at the absorption peak.

[0111] In one example, the light source in each detector and light source pair is configured to operate within a range of light emission powers, and wherein the processing unit is configured to control the light source to operate at the light power based on the determined absorption metric.

[0112] Therefore, the processing unit may control the light source to operate the light power in the teeth whitening mode based on the determined absorption metric.

[0113] In one example, determining the operating optical power includes utilizing a calibration tooth.

[0114] In one example, the processing unit is configured to control the light source to operate the optical power operation such that the intensity of the absorbed light is equal to the calibrated absorption intensity.

[0115] Thus, the processing unit may control the light source to operate the light power such that the intensity of light absorbed by at least one tooth of the user is equal to the calibrated absorption intensity.

[0116] In one example, each light source and detector is housed in the body such that when the body is placed adjacent to at least one tooth of a user, each light source and detector is located on opposite sides of the at least one tooth of the user.

[0117] In one example, each light source and detector is housed in the body such that when the body is placed adjacent to at least one tooth of a user, the light source and the detector are located on the same side of the at least one tooth of the user.

[0118] Figure 3 A control method 200 of a teeth whitening system is shown. The teeth whitening system includes a light source, a light detector, and a processing unit. The light source is configured so that the wavelength of the emitted light can be adjusted within an operating wavelength range. The detector is configured to detect the light emitted by the light source. The method 200 includes:

[0119] In the control step 210, also referred to as step a), the processing unit controls the light source to adjust the wavelength of the light emitted by the light source to a plurality of different wavelengths;

[0120] In the determination step 220, also referred to as step b), the processing unit determines the absorption measure at different wavelengths based on the detected light at different wavelengths; and

[0121] In a utilizing step 230, also referred to as step c), the processing unit utilizes the determined absorption metric to operate the light source at the wavelength at the absorption peak.

[0122] The light source and the detector may be housed in a body, and the body may be configured to be placed adjacent to at least one tooth of a user.

[0123] Thus, the light source may be configured to emit light that may be transmitted and / or reflected and / or scattered from at least one tooth of a user.

[0124] Thus, the detector may be configured to detect light emitted by the light source that is transmitted and / or reflected and / or scattered from at least one tooth of the user.

[0125] Therefore, the processing unit can be configured to control the light source to adjust the wavelength of light emitted by the light source, and determine the absorption measurement of at least one user's tooth at different wavelengths based on the detected light emitted from the light source and transmitted and / or reflected and / or scattered from at least one user's tooth when the wavelength is adjusted for different wavelengths.

[0126] The processing unit may then utilize the determined absorption metric to operate the light source in a teeth whitening mode at a wavelength at an absorption peak of at least one of the user's teeth.

[0127] In one example, the processing unit is configured to control the light source to adjust the wavelength of light emitted by the light source within an operating wavelength range of at least 400 nm to 495 nm.

[0128] According to an example, the system comprises at least one further light source, and the method comprises the processing unit controlling the at least one further light source to operate at a wavelength at an absorption peak based on the absorption measure.

[0129] Thus, in the method, the processing unit may control the at least one further light source to operate in a teeth whitening mode at a wavelength at an absorption peak based on the absorption metric.

[0130] According to an example, step c) comprises the processing unit operating at a scanning position associated with a maximum measure among the determined absorption measures.

[0131] Thus, in the method, the processing unit may be operated in a teeth whitening mode at a scanning position associated with a maximum of the determined absorption measures.

[0132] In one example, operating the processing unit at a wavelength at an absorption peak includes comparing an absorption measure when scanning the wavelength of light emitted by the light source over a range of wavelengths to one or more known absorption curves for stain molecules.

[0133] Thus, by comparing the absorption measure when the wavelength of light emitted by the light source is swept across a range of wavelengths to one or more known absorption curves of tooth stain molecules, the processing unit may be operated in a teeth whitening mode at the wavelength at the absorption peak.

[0134] In one example, the light source is configured to operate within a range of optical emission powers, and wherein the method includes the processing unit controlling the light source to operate within the optical power range based on the determined absorption metric.

[0135] Therefore, the processing unit may control the light source to operate the light power in the teeth whitening mode based on the determined absorption metric.

[0136] In one example, the method includes the processing unit controlling the light source to operate the light power so that the intensity of the absorbed light is equal to the calibrated absorption intensity.

[0137] Therefore, the processing unit may control the light source to operate the light power operation such that the intensity of light absorbed by at least one tooth of the user is equal to the required absorption intensity.

[0138] In one example, the light source and the detector are housed in the body such that when the body is placed adjacent to at least one tooth of a user, the light source and the detector are located on opposite sides of the at least one tooth of the user.

[0139] In one example, the light source and the detector are housed in the body such that when the body is placed adjacent to at least one tooth of a user, the light source and the detector are located on the same side of the at least one tooth of the user.

[0140] As described above, a personalized and automated solution for teeth whitening is provided. Systems and methods have been developed that are capable of automatically adjusting the wavelength of light incident on the teeth (and irradiance if necessary) based on the absorption feedback of the staining molecules, thereby providing significantly better whitening efficacy than current lighting concepts for teeth whitening, and better color consistency. This is achieved by sensors or detectors for retrieving data that allow information about the absorption of the staining molecules to be determined. Based on this information, the light source parameters are determined. Therefore, based on the user's teeth, the teeth whitening program is suitable for providing a personalized and automated teeth whitening solution.

[0141] Now refer to Figures 4 to 16 , the above-mentioned teeth whitening system and the control method of the teeth whitening system are further described in detail with respect to specific embodiments.

[0142] Figure 4 Absorption and transmission spectra of common stains found in teeth are shown, including carotene, tannic acid (coffee, tea), porphyrins, and fluoride stains (CaF2). It can be seen that porphyrin and tannic acid absorption is strongest at ~400nm, while carotene absorption peaks at ~450nm. Absorption of fluoride stains (especially CaF2) is also observed, which is constant between 400 and 500nm. The absorption peak wavelengths and corresponding absorption coefficients of the above-mentioned coloring molecules are calculated and summarized in the table below.

[0143]

[0144]

[0145] The inventors recognize that different coloring molecules in teeth absorb this information at different wavelengths and can be used for new teeth whitening technology without causing problems. The inventors recognize that if the wavelength of light is adjusted to the peak of the absorption spectrum of the coloring molecule, the highest absorption efficiency can be achieved, promoting the strongest reaction between hydrogen peroxide and the corresponding coloring molecule, and then achieving the shortest processing time. In addition, if the wavelength is adjusted to the peak absorption of the coloring molecule, the power consumption of the light source and the thermal relief will be minimized. This recognition has led to the development of the new technology described here, which can automatically adjust the wavelength of light incident on the teeth (if necessary, and irradiance) based on the absorption feedback of the coloring molecule, thereby providing a significantly better whitening effect than the current system, and the color consistency is better. The technology automatically targets the most common stains of a specific user, providing a truly customized and more effective teeth whitening technology, which is groundbreaking in terms of simplicity, where there is no need to know the actual wavelength of the light used in the operating teeth whitening mode (at a determined absorption peak). It is also recognized that the new technology is compatible with the oral device body currently used.

[0146] Essentially, the new technology involves identifying what wavelength within the blue light range (400 to 495nm) gives the user's teeth the strongest absorption, and automatically adjusting the wavelength (and irradiance if necessary) to provide optimized and consistent whitening efficacy. Because the scattering coefficient of teeth is constant within the blue light range (see Figure 5 , showing typical scattering coefficients for bovine incisors and human premolars, where the spectral dependence of all samples is similar and the scattering coefficient is considered constant in the range of 400 to 495 nm), the inventors realized that it is feasible to derive the absorption metric of the tooth using the transmission or diffuse reflectance metric to actually determine the absorption coefficient of the tooth. The inventors also realized that because the scattering coefficient of the tooth is constant and dominant compared to the absorption, the penetration depth of light is relatively constant in the blue light range, enabling the development of a simple solution that operates throughout this blue light range.

[0147] For transmission measurement, new technology Figure 6 Based on the Beer-Lambert law (Equation 1), the attenuation coefficient can be derived, and then the absorption coefficient can be derived.

[0148]

[0149] Where I(λ) is the transmitted light, I0(λ) is the incident light, μ t =μ′ s +μ a is the attenuation coefficient, μ′ s is the known optimized scattering coefficient, μ a is the unknown absorption coefficient and x is the known thickness of the tooth. Therefore, the absorption coefficient of the tooth can be derived based on the Beer-Lambert law after subtracting this effect from surface reflection and scattering.

[0150] For the diffuse reflectance metric, Figure 7 This concept is illustrated in , where radiation entering the tooth may be diffused away from the detector as shown in "B" and "C", but some of it may be diffusely reflected along the path to the detector as shown in "A". Based on the Kubelka-Munk (KM) model, the absorption coefficient can be derived from the measured diffuse reflectance and the known scattering coefficient (Equation 2).

[0151]

[0152] Where R ∞ is the detected diffuse reflection, μ s is a known constant scattering coefficient in the blue wavelength range, and μ a is the unknown absorption coefficient. Therefore, the absorption coefficient ratio of the tooth at different wavelengths can be derived.

[0153] In specific embodiments, the goal of improving the efficacy and consistency of teeth whitening can be achieved by taking one or the other or both of the following approaches:

[0154] a) Adjust wavelength The wavelength of the light source may be adjusted to the optimum wavelength (i.e., the peak absorption wavelength of the tooth stains) for maximum absorption (i.e., the measured absorption coefficient is at a maximum value). Transmission or diffuse reflectance measurement may be used. When the wavelength is adjusted to the optimum wavelength (i.e., the peak absorption wavelength of the tooth stains), the shortest treatment time or the minimum power consumption / heat relief may be achieved. To achieve the goal of the shortest treatment time, the light source may be operated in a continuous mode. To achieve the goal of the minimum power consumption / heat relief, the light source may be operated in a pulsed mode.

[0155] Example:

[0156] The input optical power is constant I0 and the wavelength can be tuned in the range of 400nm to 495nm.

[0157] i) For the transmission measurement: Assume that at wavelength λ x At (400≤x≤495), the detected transmitted light power is minimum (I min ), based on the fact that the tooth scattering coefficient is constant between 400 and 495 nm, the wavelength λ is converted to x Determine the optimal wavelength to maximize absorption.

[0158] ii) For diffuse reflectance measurement: Assume that at wavelength λ x (400≤x≤495), based on the diffuse reflectance (R ∞ ) is the ratio of the tooth absorption coefficient to the tooth scattering coefficient (μ a / μ s ) is the largest, based on the fact that the tooth scattering coefficient is constant between 400 and 495 nm, the wavelength λ x Determine the optimal wavelength to maximize absorption.

[0159] (b) Adjusting irradiance (while keeping the wavelength constant) to ensure that the absorbed optical power is equal to the optical power of the calibration tooth at the most common chromaticity (e.g. 12.5). Either the transmission or diffuse reflectance metric can be used. When the attenuated optical power is equal to the optical power of the calibration tooth, the absorbed optical power is also equal to the optical power of the calibration tooth based on the fact that the tooth scattering coefficient is constant between 400nm and 495nm.

[0160] (C) Combine (a) and (b) and adjust the wavelength and irradiance.

[0161] Example:

[0162] The wavelength of the light source is constant at 460nm, and the input optical power is 0x The total attenuated optical power from the calibration tooth is a constant I t0 .

[0163] i) For transmission measurement: Assuming that the input optical power I 0x The total attenuated optical power I tx =I 0x -I x Equal to I t0 , where I x is the detected transmitted light power, then based on the fact that the tooth scattering coefficient is constant between 400nm and 495nm, the input light power I 0x The optimum power is determined to provide an absorbed optical power equivalent to that of the calibration tooth.

[0164] ii) For diffuse reflectance measurement: Assume that the input optical power I 0x Based on the known tooth scattering coefficient (μ s) and the diffuse reflectance (R ∞ ), the tooth absorption coefficient is calculated as μ a When the total attenuated optical power I tx =I 0x -I 0x e -μt Equal to I t0 , where μ t =μ s’ +μ a Based on the fact that the tooth scattering coefficient is constant between 400nm and 495nm, the input optical power I 0x The optimum power is determined to provide an absorbed optical power equivalent to that of the calibration tooth.

[0165] With regard to the above-mentioned method (a), four specific embodiments will now be described.

[0166] Method (a) Example 1 : This embodiment utilizes transmission measurement, where the light source and detector are located in the body or oral device so that when the body / oral device is placed around the teeth, the light source is located on the buccal side and the detector is located on the lingual side. Figures 8 to 9 It is shown in Figure 8 The schematic diagram of the mechanism of Embodiment 1 is shown. Fig. 9 The layout of Example 1 is shown. Figure 8 As shown, light is transmitted from the buccal side to the lingual side of the tooth and interacts with the enamel, dentin and even the pulp in the process. Hydrogen peroxide having light absorption at the absorption peak of the stain molecule promotes and enhances the reaction between hydrogen peroxide and the stain molecule, thereby improving the effectiveness of stain removal.

[0167] The main body or oral device is Fig. 9 As shown in , (one or more) light sources (e.g., LEDs, lasers) with adjustable wavelengths and (one or more) corresponding detectors can be mounted at different locations on the oral device / body. One or more detectors (e.g., photodiodes, thermal power sensors, pyroelectric sensors) can be calibrated to have a flat response in the blue light range. If only one light source / detector pair is used, the light source / detector pair can be mounted at a front tooth and used as a sensor for wavelength optimization purposes. (One or more) additional light sources and waveguides can be used to provide illumination of the selected optimized wavelength from the buccal side. If multiple light sources with adjustable wavelengths and corresponding detectors are used, each light source / detector pair has two functions: a sensor for wavelength optimization purposes and an illumination provider (a light source for providing appropriate irradiance on the teeth). The size and gap of the light source can be optimized (depending on the (one or more) light sources used) to provide customized illumination on the tooth surface. The position of the light source and detector can be fixed, and the distance between the light source and the paired detector is known.

[0168] Illumination optimization can be achieved by tuning the wavelength using a light source / detector pair to the tooth's absorption peak in the blue wavelength range (400 to 495 nm). Figure 6 A schematic diagram of the mechanism of Embodiment 1 is shown. Figure 7 The layout of Example 1 is shown.

[0169] Method (a) Example 2 : This embodiment utilizes transmission measurement, where the light source and detector are located in the body or oral device so that when the body / oral device is placed around the teeth, the light source is located on the lingual side and the detector is located on the buccal side. Fig.10 The schematic diagram of the mechanism of embodiment 2 is shown, and its layout is similar to Fig. 9 is similar to that shown, except that the positions of the light source and the detector are reversed. Fig.10 As shown, light is transmitted from the lingual side of the tooth to the buccal side, and in the process interacts with the enamel, dentin and even the pulp. Hydrogen peroxide with light absorption at the absorption peak of the stain molecule promotes and enhances the reaction between hydrogen peroxide and the coloring molecule, thereby improving the effectiveness of stain removal. Similarly, (one or more) light sources (such as LEDs, lasers) with adjustable wavelengths and (one or more) corresponding detectors can be installed at different positions on the oral device / body to serve as sensors for wavelength optimization purposes. (One or more) additional light sources and waveguides with adjustable wavelengths can be used to provide illumination of selected optimized wavelengths from the buccal side. By using a light source / detector pair to adjust the wavelength to the absorption peak of the tooth in the blue wavelength range (400 to 495nm), illumination optimization can be achieved. Similarly, (one or more) detectors (such as photodiodes) can be calibrated to have a flat response in the blue light range, and the positions of the light source and detector can be fixed, and the distance between the light source and the paired detector is known. It should be noted in this embodiment that (one or more) additional light sources on the buccal side of the tooth may be required to achieve whitening of the front surface of the tooth.

[0170] Method (a) Example 3 : This embodiment utilizes diffuse reflectance measurement, where the light source and detector are located in the body or oral device so that when the body / oral device is placed around the teeth, the light source and detector are both located on the buccal side. Fig.11 The schematic diagram of the mechanism of the embodiment 3 is shown. Fig. 9 It can be clearly seen from the layout shown that the oral device / body now has the detector and light source located on the outside or cheek side of the teeth. Fig.11As shown, light enters the buccal side and diffusely reflects back to the detector on the buccal side, and in the process interacts with enamel, dentin and even pulp. Hydrogen peroxide with light absorption at the absorption peak of the stain molecule also promotes and enhances the reaction between hydrogen peroxide and the coloring molecule, thereby improving the effectiveness of stain removal. Similarly, (one or more) light sources (such as LEDs, lasers) with adjustable wavelengths and (one or more) corresponding detectors can be installed at different positions on the oral device / main body. (One or more) light sources (such as LEDs, lasers) with adjustable wavelengths can be installed at different positions on the oral device / main body to serve as sensors for wavelength optimization purposes. If only one light source / detector pair is used, the light source / detector pair can be installed at a front tooth to serve as a sensor for wavelength optimization purposes. (One or more) additional light sources and waveguides can be used to provide illumination of selected optimized wavelengths from the buccal side. If multiple light sources with adjustable wavelengths and corresponding detectors are used, each light source / detector pair has two functions: sensors for wavelength optimization purposes and lighting providers (light sources for providing appropriate irradiance on teeth). The size and spacing of the light sources can be optimized (depending on the light source(s) used) to provide customized illumination on the tooth surface. Illumination optimization can be achieved by using a light source / detector pair to tune the wavelength to the absorption peak of the tooth in the blue wavelength range (400 to 495 nm). Likewise, the detector(s) (e.g., photodiodes) can be calibrated to have a flat response in the blue light range, and the positions of the light sources and detectors can be fixed, and the distance between the light source and paired detector is known.

[0171] Method (a) Example 4 : This embodiment utilizes diffuse reflectance measurement, where the light source and detector are located in the body or oral device so that when the body / oral device is placed around the teeth, the light source and detector are both located on the lingual side. Fig.12 The schematic diagram of the mechanism of the embodiment 4 is shown. Fig. 9 It can be clearly seen from the layout shown that the oral device / body now has the detector and light source located on the inner side or tongue side of the teeth. Fig.12As shown, light enters the tongue side and diffusely reflects back to the detector on the tongue side, and in the process interacts with enamel, dentin and even pulp. Hydrogen peroxide with light absorption at the absorption peak of the stain molecule also promotes and enhances the reaction between hydrogen peroxide and the coloring molecule, thereby improving the effectiveness of stain removal. (One or more) light sources (such as LEDs, lasers) with adjustable wavelengths can be installed at different positions on the oral device / body to serve as sensors for wavelength optimization purposes. If only one light source / detector pair is used, the light source / detector pair can be installed at a front tooth to serve as a sensor for wavelength optimization purposes. (One or more) additional light sources and waveguides can be used to provide illumination of selected optimized wavelengths from the buccal side. If multiple light sources with adjustable wavelengths and corresponding detectors are used, each light source / detector pair has two functions: sensors for wavelength optimization purposes and lighting providers (light sources for providing appropriate irradiance on teeth). The size and gap of the light source can be optimized (according to the (one or more) light sources used) to provide customized illumination on the tooth surface. Illumination optimization can be achieved by using a light source / detector pair to adjust the wavelength to the absorption peak of the teeth in the blue wavelength range (400 to 495 nm). Likewise, the detector(s) (e.g., photodiodes) can be calibrated to have a flat response in the blue light range, and the positions of the light source and detector can be fixed, and the distance between the light source and paired detector is known.

[0172] With regard to the above-mentioned method (b), four specific embodiments will now be described.

[0173] Method (b) Example 1 : This embodiment utilizes transmission measurement, where the light source and detector are located in the body or oral device so that when the body / oral device is placed around the teeth, the light source is located on the buccal side and the detector is located on the lingual side. Fig.13 The schematic diagram of the mechanism of embodiment 1 is shown, and its layout is similar to Figure 8 Similar to the one shown in Fig.13As shown, light is transmitted from the buccal side of the tooth to the lingual side, and in the process interacts with the enamel, dentin and even the pulp. Hydrogen peroxide with light absorption at the absorption peak of the stain molecule promotes and enhances the reaction between hydrogen peroxide and the coloring molecule, thereby improving the effectiveness of stain removal. (One or more) light sources (e.g., LED, laser) with a fixed wavelength (e.g., 405 / 420 / 440 / 460nm) with adjustable irradiance (by adjusting the power of the light source) on the tooth and (one or more) corresponding detectors can be installed at different positions on the oral device / body. If only one light source / detector pair is used, the light source / detector pair can be installed at a front tooth to serve as a sensor for irradiance optimization purposes. (One or more) additional light sources and waveguides can be used to provide illumination of selected optimized irradiance from the buccal side. If multiple light sources with adjustable irradiance and corresponding detectors are used, each light source / detector pair has two functions: a sensor for irradiance optimization purposes and an illumination provider (a light source for providing appropriate irradiance on the tooth). The size and spacing of the light sources can be optimized (depending on the light source(s) used) to provide customized illumination on the tooth surface. Illumination optimization can be achieved by adjusting the irradiance on the tooth so that the absorbed light power is equal to a calibrated tooth of the most common chromaticity (e.g., 12.5).

[0174] Method (b) Example 2 : Transmission measurement in which the light source and detector are located in the body or oral device so that when the body / oral device is placed around the teeth, the light source is located on the lingual side and the detector is located on the buccal side. Fig.14 The schematic diagram of the mechanism of embodiment 1 is shown, and its layout is similar to that of Fig.13 Similar to the one described above, except that the positions of the light source and the detector are reversed. Fig.14As shown, light is transmitted from the lingual side of the tooth to the buccal side, and in the process interacts with the enamel, dentin and even the pulp. Hydrogen peroxide with light absorption at the absorption peak of the stain molecule promotes and enhances the reaction between hydrogen peroxide and the coloring molecule, thereby improving the effectiveness of stain removal. (One or more) light sources (e.g., LED, laser) with a fixed wavelength (e.g., 405 / 420 / 440 / 460nm) with adjustable irradiance (by adjusting the power of the light source) on the tooth and (one or more) corresponding detectors can be installed at different positions on the oral device / body. If only one light source / detector pair is used, the light source / detector pair can be installed at a front tooth to serve as a sensor for irradiance optimization purposes. (One or more) additional light sources and waveguides can be used to provide illumination of selected optimized irradiance from the buccal side. If multiple light sources with adjustable irradiance and corresponding detectors are used, each light source / detector pair has two functions: a sensor for irradiance optimization purposes and an illumination provider (a light source for providing appropriate irradiance on the tooth). The size and spacing of the light sources can be optimized (depending on the light source(s) used) to provide customized illumination on the tooth surface. Illumination optimization can be achieved by adjusting the irradiance on the tooth so that the absorbed light power is equal to the calibration tooth for the most common chromaticity (e.g., 12.5). It should be noted in this embodiment that additional light source(s) on the buccal side of the tooth may be required to achieve whitening of the front surface of the tooth.

[0175] Method (b) Example 3 : This embodiment utilizes diffuse reflectance measurement, where the light source and detector are located in the body or oral device so that when the body / oral device is placed around the teeth, the light source and detector are both located on the buccal side. Fig.15 The schematic diagram of the mechanism of Embodiment 3 is shown, and it will be clear from the above discussion that the oral device / body now has a detector and a light source located on the outside or buccal side of the teeth. Fig.15As shown, light enters the buccal side and diffusely reflects back to the detector on the buccal side, and in the process interacts with the enamel, dentin and even the pulp. Hydrogen peroxide with light absorption at the absorption peak of the stain molecule also promotes and enhances the reaction between hydrogen peroxide and the coloring molecule, thereby improving the effectiveness of stain removal. (One or more) light sources (e.g., LED, laser) with a fixed wavelength (e.g., 405 / 420 / 440 / 460nm) with adjustable irradiance (by adjusting the power of the light source) on the teeth and (one or more) corresponding detectors can be installed at different positions on the oral device. If only one light source / detector pair is used, the light source / detector pair can be installed at a front tooth to serve as a sensor for irradiance optimization purposes. (One or more) additional light sources and waveguides can be used to provide illumination of selected optimized irradiance from the buccal side. If multiple light sources with adjustable irradiance and corresponding detectors are used, each light source / detector pair has two functions: a sensor for irradiance optimization purposes and an illumination provider (a light source for providing appropriate irradiance on the teeth). The size and spacing of the light sources can be optimized (depending on the light source(s) used) to provide customized illumination on the tooth surface. Illumination optimization can be achieved by adjusting the irradiance on the tooth so that the absorbed light power is equal to a calibrated tooth of the most common chromaticity (e.g., 12.5).

[0176] Method (b) Example 4 : This embodiment utilizes diffuse reflectance measurement, where the light source and detector are located in the body or oral device so that when the body / oral device is placed around the teeth, the light source and detector are both located on the lingual side. Fig.16 The schematic diagram of the mechanism of Embodiment 4 is shown, and it will be clear from the above discussion that the oral device / body now has a detector and a light source located on the inner side or tongue side of the teeth. Fig.16As shown, light enters the tongue side and diffusely reflects back to the detector on the tongue side, and in the process interacts with the enamel, dentin and even the pulp. Hydrogen peroxide with light absorption at the absorption peak of the stain molecule also promotes and enhances the reaction between hydrogen peroxide and the staining molecule, thereby improving the effectiveness of stain removal. (One or more) light sources (e.g., LED, laser) with a fixed wavelength (e.g., 405 / 420 / 440 / 460nm) with adjustable irradiance (by adjusting the power of the light source) on the teeth and (one or more) corresponding detectors can be installed at different positions on the oral device. If only one light source / detector pair is used, the light source / detector pair can be installed at a front tooth to serve as a sensor for irradiance optimization purposes. (One or more) additional light sources and waveguides can be used to provide illumination of selected optimized irradiance from the buccal side. If multiple light sources with adjustable irradiance and corresponding detectors are used, each light source / detector pair has two functions: a sensor for irradiance optimization purposes and an illumination provider (a light source for providing appropriate irradiance on the teeth). The size and spacing of the light sources can be optimized (depending on the light source(s) used) to provide customized illumination on the tooth surface. Illumination optimization can be achieved by adjusting the irradiance on the tooth so that the absorbed light power is equal to a calibrated tooth of the most common chromaticity (e.g., 12.5).

[0177] In a further exemplary embodiment, a computer program or a computer program element is provided, characterized in that it is configured to execute the method steps according to one of the preceding embodiments on a suitable system.

[0178] Therefore, the computer program element can be stored on a computer unit, which can also be part of an embodiment. The computing unit can be configured to perform or cause the steps of the above method to be performed. In addition, it can also be configured to operate the components of the above system. The computing unit can be configured to automatically operate and / or execute the user's commands. The computer program can be loaded into the working memory of the data processor. Therefore, the data processor can be equipped to perform the method according to one of the aforementioned embodiments.

[0179] This exemplary embodiment of the invention covers both a computer program that uses the present disclosure from the beginning and a computer program that turns an existing program into a program that uses the present invention by means of an update.

[0180] Furthermore, the computer program element may be able to provide a program of an exemplary embodiment of all necessary steps to implement the method described above.

[0181] According to another exemplary embodiment of the present disclosure, a computer-readable medium, such as a CD-ROM, a USB memory stick or the like, is proposed, wherein the computer-readable medium has a computer program element stored thereon, the computer program element being as described in the preceding section.

[0182] The computer program may be stored and / or distributed on appropriate media, such as optical storage media or solid-state media provided with or as part of other hardware, but may also be distributed in other forms, such as via a network or other wired or wireless telecommunication system.

[0183] However, the computer program may also be presented over a network, like the World Wide Web, and may be downloaded from such a network into a working memory of a data processor. According to another exemplary embodiment of the present disclosure, a medium for making a computer program element available for downloading is provided, the computer program element being arranged to perform a method according to one of the aforementioned embodiments of the present invention.

[0184] It should be noted that embodiments of the present invention are described in conjunction with different subject matters. In particular, some embodiments are described in conjunction with method claims and others are described in conjunction with device claims. However, those skilled in the art will recognize from the above and following descriptions that, unless otherwise stated, any combination of features related to different subject matters, in addition to any combination of features belonging to one type of subject matter, is also considered to be disclosed with this application. However, all features may be combined if the synergistic effect is better than the simple superposition of features.

[0185] Although the present invention has been described and illustrated in detail in the drawings and the above description, such description and illustration should be regarded as illustrative or exemplary rather than restrictive. The present invention is not limited to the disclosed embodiments. Other variations of the disclosed embodiments may be understood and implemented by those skilled in the art in the process of practicing the claimed invention by studying the drawings, the disclosure and the appended claims.

[0186] 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 fulfill several functions recited in the claims. The 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. Any reference signs in the claims should not be construed as limiting the scope thereof.

Claims

1. A tooth whitening system (10), comprising: Light source (30); A light detector (40); as well as Processing unit (50); wherein the light source and the detector are housed in a body, and the body is configured to be placed adjacent to at least one tooth of a user; wherein the light source is configured such that the wavelength of the emitted light can be adjusted within an operating wavelength range; wherein the detector is configured to detect light emitted from the light source that is transmitted and / or reflected and / or scattered from the at least one tooth of the user; The processing unit is configured as follows: controlling the light source to adjust the wavelength of the light emitted by the light source, and determining absorption metrics for different wavelengths based on the light detected for the different wavelengths; as well as Wherein the processing unit is configured to operate the light source at a wavelength at an absorption peak using the determined absorption metric.

2. The tooth whitening system according to claim 1, wherein the processing unit is configured to control the light source to adjust the wavelength of the light emitted by the light source within the operating wavelength range of at least 400 nm to 495 nm.

3. A tooth whitening system according to any one of claims 1 to 2, wherein the system comprises at least one further light source, and wherein the processing unit is configured to operate the at least one further light source at a wavelength at the absorption peak based on the absorption metric.

4. A tooth whitening system according to claim 3, wherein the processing unit is configured to operate at a wavelength scan position associated with a maximum in the determined absorbance metric.

5. The teeth whitening system according to any one of claims 1 to 2, wherein the processing unit is configured to operate at the wavelength at the absorption peak comprises: The absorption measurements for the different wavelengths of the light emitted by the light source are compared to one or more known absorption curves for stain molecules.

6. A teeth whitening system according to any one of claims 1 to 2, wherein the light source is configured to operate within a range of light emission powers, and wherein the processing unit is configured to control the light source to operate at an operating light power based on the determined absorption metric. 7 . The teeth whitening system according to claim 6 , wherein the processing unit is configured to control the light source to operate at the operating light power so that the intensity of the absorbed light is equal to the required absorption intensity.

8. A teeth whitening system according to any one of claims 1 to 2, wherein the light source and the detector are housed in a body such that when the body is placed adjacent to at least one user's tooth, the light source and the detector are located on opposite sides of the at least one user's tooth.

9. A teeth whitening system according to any one of claims 1 to 2, wherein the light source and the detector are housed in a body such that when the body is placed adjacent to at least one user's tooth, the light source and the detector are located on the same side of the at least one user's tooth.

10. A tooth whitening system (100), comprising: a plurality of light sources (120); a plurality of light detectors (130); as well as A processing unit (140); wherein the plurality of light sources and the plurality of detectors are housed in a body, and the body is configured to be placed adjacent to at least one tooth of a user Wherein each light source is paired with a detector; wherein each light source is configured such that the wavelength of the emitted light can be adjusted within an operating wavelength range; wherein each detector is configured to detect light transmitted and / or reflected and / or scattered from said at least one user's tooth emitted from said paired light source; wherein for each light source and detector pair, the processing unit is configured to control each light source to adjust the wavelength of the light emitted by the light source, and is configured to determine absorption metrics for different wavelengths based on the light detected for the different wavelengths; as well as Wherein for each light source and detector pair, the processing unit is configured to operate the light source in each light source and detector pair at a wavelength at an absorption peak using the determined absorption metric.

11. The teeth whitening system of claim 10, wherein the processing unit is configured to control each light source to operate at a wavelength that is independent of an operating wavelength of any of the other light sources.

12. A control method (200) of a teeth whitening device, the teeth whitening system comprising a light source, a light detector and a processing unit, wherein the light source and the detector are housed in a body, and the body is configured to be placed adjacent to at least one tooth of a user, wherein the light source is configured so that the wavelength of the emitted light can be adjusted within an operating wavelength range, wherein the detector is configured to detect the light emitted from the light source, and wherein the method comprises: a) controlling, by means of the processing unit, the light source to adjust the wavelength of the light emitted by the light source that is transmitted and / or reflected and / or scattered from the at least one tooth of the user; b) determining, by the processing unit, absorption measures for the different wavelengths based on the light detected for the different wavelengths; as well as c) operating, by said processing unit, said light source at an absorption peak using said determined absorption measure.

13. The method of claim 12, wherein the system comprises at least one further light source, and the method comprises: The at least one further light source is controlled, by the processing unit, to operate at a wavelength at the absorption peak based on the absorption measure.

14. The method according to claim 13, comprising: By means of the processing unit, operation is performed at the wavelength scan position associated with a maximum in the determined absorption measure.

15. A computer program product for controlling a system according to any one of claims 1 to 9 or a system according to any one of claims 10 to 11, wherein when executed by a processor, the computer program element is configured to perform the method according to any one of claims 12 to 14.

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