Although the effect of teeth whitening is undeniable, there are cases that teeth whitening does not work well on. Thorough consultation with the dentist helps him evaluate if you are a candidate for teeth whitening or not. Whitening may not be an option if:

• You are children with mixed dentition
• You have tooth-colored restorations such as veneers, crowns or fillings
• Teeth with yellow color are likely to be bleached well while brown teeth may not respond to bleaching agents as well and whitening procedure does not work effectively on teeth with gray tones at all
• Heavily stained teeth caused by medication (like tetracycline) or severe trauma are much less likely to respond to whitening procedure