A very frequent technique used in the last period in the dental offices is the dental whitening. The teeth's whitening is a proceeding for discoloration of the dentine and of the enamel spots and implicitly the whitening of the teeth.
    The whitening treatment had a great success, already from its introduction as a solution in case of color modification. At the present time 2.5 millions of peoples from North America are requesting this service in one year. To this figure we have to add also the persons who need a new whitening treatment, proceeding necessary after a period of 2-3 years.

    Dental Coloration

    There are different causes for the coloration of teeth: consumption of coloring substances (tee, coffee, tobacco), aging, traumas, excessive fluoridation, degeneration of the nerves and old fillings. The recolour of the teeth following the whitening treatment is due to the same factors which caused the first coloration.

    Instructions

    The ideal candidates are patients with natural teeth, having yellow, brown or orange spots and the patients with spotted teeth due to smoking, aging or other extrinsic causes. The strong spots, i.e. the ones caused by consumption of antibiotics, will need a longer treatment and the results will not be very successful.
    The success of the treatment and the whitening degree of the natural teeth depends, form patient to patient, on the structure of each teeth, the treatment method and the duration of the whitening system, the concentration of the active substance (attention - the concentration must not be the maximum one, it has to be a balanced one subject to the sensitivity of the teeth, fact which will be established by the dentist).
    All the known whitening systems are efficient only on natural teeth. In case of dental restorations (fillings, prosthetic works) the efficiency of the whitening substances is null. That's why each treatment, which foresees a filling or prosthetic works, involves an information of the patient, performed by the dentist, and each whitening proceeding shall be performed before the restoration treatment.

    Mechanism

    The chemical process for the whitening is very simple. Peroxides and effervescent peroxides from the whitening substance are brought in intimate contact with the tooth, the oxygen being released from these materials and decomposed in its component parts. The oxygen enters in combination with the color molecules stored at the level of the reticular structure of the enamel and dentine canaliculis, increasing the solubilisation degree. The products resulting from the whitening include: oxygen, water and ammoniac, products which normally exist in the organism.

    Precautions

    The use of the whitening substances is not indicated in case of pregnancy and nursing. In any other situations some precautions are needed: the health of the gums must be good, the presence of the mineralization deficit of the dental substance in some areas determines a more rapid discoloration, the result being a chalk aspect, in areas with gums' retraction a sensitivity can appear, the same sensation can appear, in some cases, at several teeth. Under these circumstances it is necessary to connect the dentist. The risk of swallowing the whitening substance is reduced by the fact that the substance does not cause any disorder at the level of the organism, in some cases the taste can be unpleasant.

    Whitening Methods

    - The whitening at home is the most used method, the patient is using a cap splint in which the whitening substance is introduced and this is worn by the patient at least 6 hours (depending on the commercial product). Normally the dentist recommends the use of this method during the night. The proceeding is repeated 6 up to 10 nights.
    - The whitening at the dental office, not so often used, is more comfortable for the patient, being performed by the dentist - in this case the appearing of the sensitivity at several teeth is more frequent.
    - The whitening with laser - the use of continuous light rays to improve the effect of the whitening is a recent technique. It was used for the first time in 1996. The comfort and the reduced time of use (about 30 min for one arch) are establishing the high cost of this method.
    - The whitening with strict commercial products have an reduced efficiency, but a long term use can lead to a slight discoloration and implicitly to the whitening of the natural teeth.

    Conclusion

    The proceeding of dental whitening is a relative new method in our country (the first kits for whitening were imported in the middle of the '90) in comparison with the USA, country where the whitening systems have a successful 30 years history. The risks and disadvantages in case of using whitening techniques are extremely reduced in comparison with the results, which most of the time are spectacular with a minimum effort for the patient.