a dental bleaching device may include a flexible backing material , and a dental composition in contact with the flexible backing material . the dental composition may include a thickening agent and a peroxide bleaching agent . the dental composition may be a gelatinous compound having physical deformation properties that allow the dental composition to bend and conform to a shape of a container into which the dental composition is placed , but the dental composition will not merge into a second piece of the dental composition when placed in contact with the second piece . the dental composition will not crack or break when the dental bleaching device is flexed .