Method of whitening teeth

A method of whitening teeth comprising:

• dispensing a tooth whitening composition onto a mouth tray;
• emitting light onto the tooth whitening composition on the mouth tray for a first period of time;
• after expiration of the first period of time, inserting the mouth tray into an oral cavity of a user so that the user's teeth are in contact with the tooth whitening composition on the mouth tray for a second period of time to achieve a desired whitening effect;
• and
• wherein a sum of the first and second periods of time equals a total treatment time, and wherein the first period of time is at least 20% of the total treatment time;
• and
• wherein the first period of time initiates a chemical change in the tooth-whitening composition prior to contact of the tooth-whitening composition with the user's teeth, and wherein the second period of time required to achieve the desired whitening effect is reduced as a result of the initiated chemical change.

A method of whitening teeth comprising:

• dispensing a tooth whitening composition onto a mouth tray;
• emitting light onto the tooth whitening composition on the mouth tray for a non-contact treatment time;
• and
• inserting the mouth tray into an oral cavity of a user so that the user's teeth are in contact with the tooth whitening composition on the mouth tray for a contact treatment time to achieve a desired whitening effect;
• wherein a ratio of the non-contact treatment time to the contact treatment time is approximately 1:1;
• and
• wherein the non-contact treatment time initiates a chemical change in the tooth-whitening composition prior to contact of the tooth whitening composition with the user's teeth, thereby reducing the contact time required to achieve the desired whitening effect by at least 20% relative to a whitening method of equal total duration in which the non-contact treatment time is omitted.