Frequently Asked Questions
Why do teeth discolour?
As a person ages the adult teeth often become darker due to changes in the mineral structure of the tooth, as the enamel becomes less porous. Teeth can also become stained by bacterial pigments, some coloured food such as coffee, tea, red wine, and tobacco. Some antibiotic medications (eg tetracycline) can also lead to teeth stains or a reduction in the brilliance of the enamel.. This means that how easily teeth stain and how easily they whiten varies from person to person.
Who is a good candidate for teeth whitening?
There are two kinds of staining on teeth: Extrinsic and Intrinsic. Extrinsic or superficial staining comes from things we eat, drink or expose to our teeth. This kind of stain is usually yellowish in nature and yields the best results with teeth whitening. Intrinsic staining is from things we absorb into our bodies such as minerals, fluoride, antibiotics such as tetracycline during the key developmental stages of the formation of the teeth. These substances permanently discolour teeth and to the point that no teeth whitening system will have a positive effect. People will often choose to whitening them instead with veneers, or crowns, which addresses the teeth colour as well as can reshape them.
How does whitening work?
Oxidizing agents such as hydrogen peroxide or carbamide peroxide are used to lighten the shade of the tooth. The oxidizing agent penetrates the porosities in the rod-like crystal structure of enamel and oxidizes interprismatic stain deposits; over a period of time, the dentin layer, lying underneath the enamel, is also bleached.
How long does whitening generally last?
Longevity will vary depending on each person and lifestyle. Most people will choose to use one of the many simple methods our office provides to maintain their white teeth over time. We have found that with most of our clients, once whitened, their teeth never return to their original darker shade. Results generally last 2-3 years.
Will teeth whitening be harmful to my teeth?
No. Studies show that with normal or suggested use of teeth whitening products, there is no harmful effects on teeth. It is common for some people to experience tooth sensitivity during whitening phase which will generally subside after a day or two after completion of treatment.
What about dark rooted filled teeth or internal staining?
Internal staining of dentin can discolor the teeth from inside out. Internal bleaching can remedy this. To do this, we usually seal off the root canals, and place the bleach inside the tooth, place a temporary filling over the bleach filled tooth and let it sit for a few days, after which we repeat the process until the desired colour is achieved.
Tetracyline Stained Teeth
If tetracycline damage is present on a patient's teeth, and whitening is ineffective, there are other methods of whitening teeth. Bonding, when a thin coating of composite material is applied to the front of a person's teeth and then cured with a blue light can be performed to mask the staining. A veneer can also mask tooth discoloration.