Teeth whitening

摘要

A method of whitening teeth comprises dehydrating a tooth and then applying a bleaching solution to the tooth, the teeth can be in a living being and can be dehydrated using suction, heating, a stream of gas or applying a hydroscopic material to each tooth. The tooth or a photograph of the teeth may be compared with a white-scale and the tooth is dehydrated until it is whiter than the initial reading against the white scale. A cast 10 may be taken of the teeth 20 to be used to form a tray for use in the whitening method. The cast 10 may have a groove 22 formed across a tooth at a distance from point at which the teeth 20 meets the gum 21 so that the tray is formed with a barrier to help prevent bleaching solution coming into contact with any exposed dentine, the gingival border 23 and the gum 21.