Cosmetic dentistry

Tooth whitening

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.

What is a teeth whitening?

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.

What limitations does it have?

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).

What are the dangers of performing teeth whitening without the supervision of a dentist?

There are currently a multitude of products that the user can get in order to obtain whiter teeth.
It is important to make a previous diagnosis to rule out diseases in the teeth and gums, such as gingivitis or cavities, which may contraindicate teeth whitening without having previously treated these diseases.
Another problem with performing unsupervised teeth whitening is that when using abrasive products, they can create burns on the gums and mucous membranes, and even lead to the death of the tooth if the pulp is affected.

Whitening strips, activated carbon, hydrogen peroxide, LED lights… are they safe?

-Gels and whitening strips:
The products and whitening gels that can be obtained as KITS to whiten teeth, have a very low concentration of whitening substances, and are regulated by European regulations, allowing a concentration of no more than 0.1% for acquisition for non-professional use. Therefore, they have very little long-term effect, they can only prevent or eliminate small stains.
-Whitening with light:
On the other hand, whitening with light only works if it is combined with certain products and they have to be carried out in a professional center and under dental supervision, since they can damage the dental pulp due to an excess of temperature.
-Activated carbon:
The use of activated carbono r charcoal, which is so fashionable in social media, is an element that has been used for many years in other areas of medicine to treat poisonings. This is due to its great adsorption capacity.
There are no studies that demonstrate their whitening ability, however they can remove small sperficial stains from the enamel. It can also be an optical effect, since staining the teeth black and then rinsing them gives the appearance that they are whiter.
Likewise, its abrasive capacity is not exactly known, therefore it is important to look at the composition of the toothpaste that contains this carbon and check its RDA (Relative Dentin Abrasion), an index that measures the abrasive capacity of the enamel of different toothpastes, which has not to exceed 200.
-Sodium bicarbonate:
Sodium bicarbonate has a low abrasive capacity, (index of 7 on the RDA scale), therefore it will be able to eliminate small superficial stains, but never whiten the tooth, since it is not capable of penetrating the dentin and modifying its color. Its use is considered safe, and in fact it is used by means of a spray with pressurized water in dental clinics as part of periodontal prophylaxis to eliminate superficial stains.
Lemon is a very acidic element, with a pH of around 2.4, which causes erosion of the enamel, with serious consequences such as tooth sensitivity and tooth pulp involvement. The more enamel is lost, the more yellow the tooth will be, as the color of the dentin will show through. Therefore lemon is NOT capable of whitening teeth.
Many components of professional whitening gels contain compounds similar to hydrogen peroxide, so their unsupervised use can pose a significant risk to the health of your teeth.

Do whitening toothpastes really whiten?

Whitening pastes are not really such, they have a small concentration of abrasive substances that can eliminate small superficial stains and that are usually indicated temporarily as maintenance after professional teeth whitening. These components do not enter the innermost layer, which is the dentin, but only act on the enamel, which is transparent, which means that the enamel is not whitened, what is whitened is the dentin.

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