Abstract: Devices for whitening teeth that include a mouth piece and an ultraviolet light source, a sterilizer that sterilizes the mouth piece, or at least one Hall-effect sensor. At least a portion of the device or mouth piece may be sterilized. A wireless charging system may drive the sterilizer or UV source, which may operate only when the mouth piece is not in the user's mouth or when the mouth piece is charging. A safety mechanism may protect the user from eye damage. The mouth piece may be charged while the mouth piece and UV source are in an enclosure. The UV source or sterilizer may turn on only while the mouth piece is in the enclosure or only while the enclosure is closed. The Hall-effect sensor(s) may control whether the UV source or sterilizer is on or may detect whether the mouth piece is docked within the charger.