Safe method for bleaching teeth

1. A method for bleaching teeth comprising:

applying a first bleaching composition having a first concentration of a first bleaching agent to teeth to be bleached;

subsequently applying a second bleaching composition having a second concentration of a second bleaching agent to the teeth while the first bleaching composition remains on the teeth; and

wherein the second concentration of the second bleaching agent in the second bleaching composition is less than the first concentration of the first bleaching agent in the first bleaching composition.

2. The method according to claim 1 , wherein the first bleaching agent in the first bleaching composition is hydrogen peroxide at a concentration between 20% and 50% (w/v).

3. The method according to claim 1 , wherein the second bleaching agent in the second bleaching composition is hydrogen peroxide at a concentration of between 0.1% and 15% (w/v).

4. The method according to claim 1 , wherein the second bleaching composition is applied to the teeth immediately following the application of the first bleaching composition to the teeth during the same teeth whitening treatment session so that the first and second bleaching compositions mix together to form a mixed bleaching composition having a mixed bleaching agent.

5. The method according to claim 4 , wherein the mixed bleaching agent is a mixture of the first and second bleaching agents, and wherein the mixed bleaching composition comprises a third concentration of the mixed bleaching agent, the third concentration of the mixed bleaching agent in the mixed bleaching composition being less than the first concentration of the first bleaching agent in the first bleaching composition.

6. The method according to claim 5 , further comprising leaving the mixed bleaching composition on the teeth for a sufficient period of time so that the third concentration of the mixed bleaching agent in the mixed bleaching composition stabilizes by diffusion, the third concentration of the mixed bleaching agent in the mixed bleaching composition decreasing over time until stabilizing.

7. The method according to claim 1 , wherein the first and second bleaching agents are the same and are one of hydrogen peroxide, carbamide peroxide, sodium perborate, and sodium percarbonate.

8. The method according to claim 7 , wherein the first and second bleaching agents are hydrogen peroxide.

9. The method according to claim 1 , wherein the first bleaching agent in the first bleaching composition has a concentration between 20% and 50% (w/v) and the second bleaching agent in the second bleaching composition has a concentration between 0.1% and 15% (w/v).

10. A method for bleaching teeth comprising:

applying a first bleaching composition having a first concentration of a first bleaching agent to teeth to be bleached;

subsequently, while the first bleaching composition remains on the teeth, applying a second bleaching composition having a second concentration of a second bleaching agent to the teeth, wherein the second concentration of the second bleaching agent in the second bleaching composition is less than the first concentration of the first bleaching agent in the first bleaching composition; and

the first and second bleaching compositions mixing together on the teeth to form a mixed bleaching composition having a mixed bleaching agent that is a mixture of the first and second bleaching agents, wherein the mixed bleaching composition comprises a third concentration of the mixed bleaching agent, the third concentration of the mixed bleaching agent in the mixed bleaching composition being less than the first concentration of the first bleaching agent in the first bleaching composition.

11. The method according to claim 10 , wherein the first bleaching agent in the first bleaching composition is hydrogen peroxide at a concentration between 20% and 50% (w/v).

12. The method according to claim 11 , wherein the second bleaching agent in the second bleaching composition is hydrogen peroxide at a concentration of between 0.1% and 15% (w/v).

13. The method according to claim 10 further comprising applying a DC current through the mixed bleaching composition, the mixed bleaching composition retained in an applicator and in contact with the teeth.

14. The method according to claim 10 wherein the third concentration of the mixed bleaching agent in the third bleaching composition decreases over time due to diffusion.

15. A method for shortening bleaching teeth treatment time comprising:

applying a first bleaching composition having a first concentration of a first bleaching agent to teeth to be bleached;

subsequently applying a second bleaching composition having a second concentration of a second bleaching agent to the teeth; and

wherein the first bleaching agent in the first bleaching composition is hydrogen peroxide at a concentration between 20% and 50% (w/v), the first bleaching composition penetrating deep within the enamel to erase embedded stains.

16. The method according to claim 15 , wherein the second bleaching composition is disposed within an applicator that is applied to the teeth, and further comprising activating the applicator to apply a DC current through the first and second bleaching compositions while the first and second bleaching compositions are retained in the applicator and in contact with the teeth.

17. The method according to claim 15 , wherein the second bleaching agent in the second bleaching composition is hydrogen peroxide at a concentration of between 0.1% and 15% (w/v).

18. The method according to claim 15 wherein the first and second bleaching agents are hydrogen peroxide.