Tooth whitening system

A tooth whitening system, comprising:

• a plurality of light sources;
• a plurality of light detectors;
• and
• a processing unit;
• wherein each light source is paired with a detector;
• wherein the plurality of light sources and the plurality of detectors are housed in a body that is configured to be placed adjacent to a plurality of the user's teeh;
• wherein, each light source is configured such that a wavelength of the light emitted is adjustable over a wavelength range of operation;
• wherein, each detector is configured to detect light emitted from the paired light source that is transmitted and/or reflected and/or scattered from the at least one of the user's teeth;
• 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 a measure of absorption for different wavelengths on the basis of the detected light for the different wavelengths;
• and
• wherein, for each light source and detector pair the processing unit is configured to utilize the determined measure of absorption to operate the light source of each light source and detector pair at a wavelength at a peak in absorption.

A method of controlling a tooth whitening device, the tooth whitening system comprising a light source, a light detector, and a processing unit, wherein the light source and detector are housed in a body and the body is configured to be placed adjacent to at least one of a user's teeth, wherein the light source is configured such that a ad to a wavelength of the light emitted is adjustable over a wavelength range of operation, 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 of the user's teeth, and wherein the method comprises:

• a) controlling by the processing unit the light source to adjust the wavelength of the light emitted by the light source;
• b) determining by the processing unit a measure of absorption for different wavelengths on the basis of the detected light for the different wavelengths;
• and
• c) utilizing by the processing unit the determined measure of absorption to operate the light source at a peak in absorption.