Teeth whitening is a process by which the stained or yellowed teeth are bleached and made whiter. Teeth whitening process can be done professionally in the dentist’s office or it can be carried out by individuals at home. The products that can be used for teeth whitening are available over the counter and can be obtained from your dentist. You can carry out teeth whitening at home under the supervision of your dentist or according to instructions given along with the product.

How does teeth-whitening work?

Teeth whitening products either available at the dentist’s office or over the counter, use two common combinations of chemicals namely, carbamide peroxide or hydrogen peroxide. They are available in the form of pastes or powders which must be mixed with water. These products, when applied to the teeth sets off a chain of reactions, which is responsible for removing stains from the teeth. These chemical reactions are oxygenation and diffusion. Oxygenation breaks down the molecules of the stain and diffusion is for diffusing the debris away created by breaking of molecules. This is a cyclical process which starts at the surface of the tooth, the enamel and proceeds further down. This is how stain removing action gets completed.

Reasons why teeth whitening does not work

There are many reasons for teeth whitening procedure to go wrong.

Doing it on your own
The best thing to do about teeth whitening is, get it done by your dentist in his office. There are very few chances of it being going wrong. Dentists are experts. They know what they are doing. They use the best products they know should work and moreover they know your requirement, your medical history and your teeth. When dentists do the teeth whitening in the office, they already have asked you about what medicine you are on. How bad the stains on your teeth are, and how much chemical will be needed, and for how long, for it to take effect.  So, if you have a choice and budget for this, you must opt for the teeth whitening done by the professional at the clinic.

Lack of preparation
One of the main reasons for failure in teeth whitening is the preparation or rather lack of it. The teeth will receive the chemicals well if they have been prepared to receive it. It means that when teeth whitening is done in the clinic, the dentist prepares the teeth by removing tartar, and cleaning them of any plaque. So when you apply the product, it will have to deal with the stains on the teeth only, nothing else.

Products bought over the counter
Another reason for failure to whiten the teeth can be the material itself. Many products contain abrasive material and do not contain the bleach at all, which clears the stains by polishing away at them rather than whitening the enamel. When the product you are using for bleaching the teeth is not strong enough, then the desired effect is not seen. Hydrogen peroxide is an active ingredient in most teeth whitening products. In some countries, hydrogen peroxide has to be less than 0.1% in the product sold over the counter, which is not enough to work on stains. This is why the home-kit used by individuals at home is not very effective at teeth whitening.

Strong chemicals in the product
Teeth whitening agents which are bought over the counter may also be more concentrated than you need. When you apply this paste, it may corrode the enamel on your teeth make them sensitive.

Not following instructions
Sometimes, the user does not follow the instructions fully. Like, you are asked to pour the content of the product into the mouth guard like tray and hold it for some time. If the tray is removed before suggested time, the chemical reaction doesn’t get completed. In this case, the stains do not get removed at all, or are removed in part.

Misinterpreting the stains on your teeth
Then there is misinterpreting the stains on your teeth. In some cases, the enamel on the teeth wears away and becomes thin, which allows the colour of dentin to show on the teeth. This colour is not a stain, but the natural colour of the teeth which cannot be whitened.

Skipping steps in the treatment
Some of the times the user does not read and follow the instructions fully and skips some of the steps. For example, when the treatment needs to be repeated every week for a few weeks and you forget to repeat it at the stipulated time, then the result may not be what you had expected.

Very high expectations from teeth whitening procedure
There are some people who expect too much from the teeth whitening procedure. It cannot totally whiten your teeth. The usual result you get is a shade or two lighters than your original shade. Do not expect to change your shade which is genetic.

Decay in the tooth
The less common reason could be a decay in the teeth which appears as a stain. This decay cannot be whitened with any product. It has to be treated by the dentist.

Rehydration
You must allow the tooth to rehydrate before reapplying the teeth whitening product.

Inhibited by previous dental work
When there is previous dental work done on the teeth, they prevent the chemicals in the product to work effectively.

Replaced teeth and crowns
You can whiten your original teeth only. Replaced teeth or crowns cannot be whitened.

Intensity of the stain
We must also remember that the darker the stain, the more intense treatment it will require. And even after repeated treatments, we cannot get rid of some stains at home.

Medicines taken for other diseases
Other reasons for teeth whitening not working includes medicines taken for any other ailment or diseases like cancer.

What we should remember is that we can whiten our teeth only to our original colour with which we are born, not whiter than that.