This can be done in the dental clinic with products activated by halogen or laser light. It can also be done at home by making tailor made casts for the teeth to contain the whitening agent.
A whitening tray is a horseshoe-shaped device made of transparent soft acrylic material, molded to the exact shape of your teeth so that they fit them perfectly, and are used to contain the whitening gel which will stay in contact with your teeth.
The external teeth whitening is now one of the simplest and conservative aesthetic resources. Although it is called external, what is trying to be whitened is the dentin. Tooth crown in its structure consists of enamel (outermost part), dentin (intermediate layer) and dental pulp (internal structure). The enamel has no color, it is translucent as glass. Dentin is what really gives us the color of teeth.
Are the teeth white?
We should know that the intrinsic inner dentin color is determined genetically, it is therefore an innate characteristic of each of us, as it is the color of our skin. They can have an infinite variety of colors within the range of white (orange-yellow, gray-green, gray-pink or reddish-brown) and within each of these groups, different gradations of intensity. The professional will determine the base color, as it is not modified by any whitening. What can be achieved is a clarification to a greater or lesser extent of the base color.
To explain it in a simple way, we are always talking about bleaching the base color that is located inside the tooth, as external stains such as those from smoking or other stains on the tooth surface, can easily be removed with a regular dental cleaning. We must differentiate between stains on the tooth surface due to external agents and the intrinsic color of the tooth. This is why cleaning and whitening are two different dental procedures.
The teeth whitening procedure
very case has to be studied in advance to avoid giving false expectations. Also mention that the intensity of bleaching depends on each patient and his/her age (having a better response in younger patients) and generally responds well in almost all teeth. In many cases of tetracycline-related tooth color (with brown or gray stripes) these gray-brown bands will not disappear, they will only become less marked. Whitening is not as "bleaching" or painting a wall.
The external teeth whitening is done without anesthesia, because is important to perceive sensibilities, as it is actually the tooth what is going to tell us how far we can whiten. It is not worth to a have very white teeth but having them hypersensible. If during the procedure much sensitivity is felt, we will have to stop and continue in another session, or even stop the treatment because definitely the tooth does not allow us to go further.
At the end of treatment and the next day teeth and the surrounding gum can and do become slightly sensitive and even occasionally may require taking painkillers the day of treatment, but we must say that these sensitivities, if any, will be temporary and of low intensity if the correct protocols are followed.
When will I see the results of whitening?
Once the whitening is performed, in a few days teeth will continue whitening and the final color obtained will remain unalterably for a 2-7 years period, depending on each patient. Although color after these years can lose intensity, the color will never be like the beginning. In the event that recurs a little, a simply shorter whitening session than the original can be performed. In the mentioned cases, whitening tooth paste can be used as a reinforcement for a certain period. Always under professional control.
Materials used in teeth whitening
Current whitening techniques are based on the use of two products, carbamide peroxide (ambulatory treatments) and hydrogen peroxide (treatments in clinic). These products are able (through heat activation and / or special light) to detach O2 molecules that can "leak" through the tooth enamel (surface tissue) until the dentinal tubules. There are about 15,000 dentinal tubules per mm2. Thus, the tissue under the enamel (dentin) which is what gives color to teeth, is the one which is going to be whitened, giving the feeling that the enamel is whiter.
Ambulatory whitening has certain limitations:
- The teeth can be whitened between 2 – 4 degrees or tones on the chromatic scale, although this is done uniformly, so that any darker areas will be lighter but will not disappear.
- The procedure is not limitless, and after reaching a certain point, the gel no longer has any effect.
- Also, the whitening effect is not permanent; some time after completing the treatment, there will be a slight return of the former colour. This darkening of around 10% can be fixed by repeating the whitening session as soon as you notice it, and can be prevented considerably by having monthly whitening sessions as maintenance.
- The whitening effect takes some time, usually several weeks. It does not happen sooner by adding more gel to the trays or wearing them for longer than recommended. The whitening process requires sessions of a specific length, and no longer (in order to reduce tooth sensitivity).