In an embodiment, a tooth whitening device includes a body having at least one LED disposed at an end of the body, and a mouthpiece removably attached to the body adjacent the LED. The mouthpiece can include an insertion end having a shape complimentary to an arch of upper and lower teeth of a user and sized to be received within the mouth of a user. The mouthpiece can include a wall at the insertion end that defines an opening. The wall surrounds buccal surfaces of the upper and lower teeth of the user such that at least a smile zone of the upper and lower teeth of the user is exposed through the opening. Light is transmitted from the LED through the opening to expose at least the smile zone of the upper and lower teeth.