Recently, teeth whitening has been one of the most demanded procedures in dentistry, which often has no medical indications for use. Changing the color of teeth, or discoloration, leads to a violation of the aesthetics of the smile and, as a result, negatively affects a person’s self-esteem and social adaptation.
Teeth whitening is a conservative method of aesthetic dentistry, aimed at eliminating discoloration of teeth of different etiology (reasons) or lightening them with the help of special chemicals.
Tooth color is mainly determined by the thickness and color of the dentin. The greater the volume of dentin in the tooth and the smaller the thickness of the enamel, such as in canines, the more yellow the teeth appear. The color of the tooth also depends on the thickness, color and transparency of the enamel, but to a lesser extent than on dentin.
In the course of a person’s life, teeth are exposed to various organic and inorganic dyes, which can settle on their surface or even stain hard dental tissues.
Depending on the reasons that caused the discoloration of the teeth, discoloration is divided into congenital and acquired.
Congenital discoloration includes:
- enamel hypoplasia;
- tetracycline teeth;
- hereditary pathologies of hard tissues of teeth (imperfect amelogenesis and dentinogenesis).
- The acquired discolourations are divided into vital and non-vital coloration.
Non-vital staining :
- dental plaque due to poor oral hygiene;
- bad habits (smoking, drinking a lot of strong tea and coffee);
- food colorings;
- green coloration associated with the development of the fungus hichen clentalis;
- industrial hazards;
- age-related changes;
- tooth injury, etc.
- depulpation of teeth;
- filling of root canals with resorcinol-formalin or zinc-oxide-eugenol paste;
- the use of filling materials containing silver;
- in-channel pins made of base metals.
Teeth whitening is carried out only after professional oral hygiene, the essence of which is to clean the surface of the teeth from tartar and dense pigmented deposits. This cleans the tooth to its natural color.
Most often teeth whitening is carried out using gels containing hydrogen peroxide or carbamide peroxide, which, when activated by a catalyst chemically, with the help of a halogen lamp, ultraviolet light or a laser, ultimately decompose to water and free atomic oxygen. Oxygen, penetrating into the enamel spaces, oxidizes tooth pigments and causes denaturation of protein compounds included in the enamel pigments, which leads to its lightening.
The concentration of the peroxides used is so small that, in contact with hard tissues, they cannot have a destructive effect on them. However, patients should be aware that whitening can accelerate the aging process of composite fillings. In the presence of such fillings after bleaching, they often need to be replaced to better match the tooth tissues. In this case, they are replaced no earlier than 2 weeks after bleaching.
To enhance the whitening effect, it is possible to carry out this procedure at home. To do this, special aligners are made (they are filled with a gel for home whitening), which must be put on the teeth for 20-40 minutes for ≈ 14 days. In case of tooth hypersensitivity, these aligners can be used with remineralizing gels.
Complications after whitening :
- the occurrence of dental hypersensitivity (eliminated by stopping the procedure and using special gels);
- chemical burn of the gums (as a rule, does not require special treatment, self-healing occurs very quickly).
Whitening contraindications :
- poor oral hygiene;
- hypersensitivity of the teeth;
- high caries activity;
- chronic diseases of the oral mucosa;
- milk teeth, patients under 18 years old.
In severe forms of discoloration, for example, the chalky-speckled form of fluorosis, the enamel microabrasion technique is used. Its essence consists in grinding the surface layer of enamel with a special mixture (low concentration hydrochloric acid, fine abrasive (carborundum) and silicon gel) and rubber cups on the holder for attaching to the teeth and carrying out manipulations with the help of a contra-angle handpiece. The use of fluorine-containing preparations after microabrasion allows to achieve good and lasting results.