Tooth whitening system includes a moldable dental tray of sufficiently moldable material so that a user can form the tray to substantially match the configuration of the user's teeth, in use. Moldable dental tray includes a raised region and a valley that are adjacent to and free of contact with a corresponding raised region and valley of a user's tooth adjacent a user's gum line. Thus, a tooth provided on the moldable dental tray is free of contact with the user's gingiva, in use. Tooth whitener includes a carrier, a whitening agent, and a sufficiently adhesive so that both the tooth whitener and the moldable dental tray are adhered to a user's tooth for a sufficiently long period of time to achieve a whitening of the user's tooth by the whitening agent. Tooth whitener and tray can be made of organic, natural materials.