Reaction Time of 22% Carbamide Peroxide 1 hour and 2 hours

Hi:It appears you have decalcification on the tooth.  This can also happen as a result of trauma while the adult tooth was developing.  Normally nothing has to done unless it develops into a cavity.Best, Dr. Maddahi

Hi:It's best to go back to your dentist to evaluate the stain.  Most likely he will be able to remove the stain with simple polishing.

I agree with Dr. Maddahi answers that without seeing your teeth it is difficult to give you correct advice but as per my opinion you should not use whitening strips on chipped tooth and visit dentist for the appropriate treatment. Dental bonding is the treatment that will fix your chipped tooth.