Tooth Whitening

Photograph showing before and and after teeth whitening procedure. 

Tooth whitening is done to correct the discoloration of a tooth. When we talk about discoloration of a tooth, we mean to say that  the color of a tooth has changed from its normal white color to  light yellow,  yellow,  light brown to dark brown  or from light grey to dark grey or  to complete black. The discolouration may be of one tooth or all the teeth may be discoloured. Discoloration of a tooth is caused by several factors. It may be due to deposition of external stains over the surfaces of a tooth or it may be because of the internal position of certain chemicals into the teeth structure at molecular level during the period when teeth were being formed in the mother’s womb.

External Discoloration of the Tooth

External stains deposited on the surface of the teeth may be due to smoking, drinking tea or coffee or food colorants like turmeric. Poor oral hygiene habits may also lead to the external discoloration of teeth.

Internal Discoloration of Vital Tooth

Tetracycline, excessive fluoride or other medication intake by a pregnant mother during developmental phase of the teeth of the foetus may result into the discoloration of the teeth as a child.

The Internal Discoloration of a Non-Vital Tooth

The discoloration of non-vital tooth is caused by the death of the pulp tissue due to trauma. In such cases, the pulp of the traumatized tooth go through the death process and becomes necrotic. The necrosis or rotting of the pulp tissues produces Sulphur compounds that give the light brown to dark grey color of that particular tooth.

Tooth Whitening Procedure

The procedure for teeth whitening depends whether the tooth is vital or non-vital.

The chemicals used for tooth whitening may be hydrogen peroxide or carbamide peroxide.

Technique of tooth whitening procedure for non-vital tooth

Color of the tooth should be matched with the shade guide and it is recorded in the patient’s file.

A successful root canal treatment of the dead tooth should be done.  Then only, a tooth whitening procedure should be performed to correct the discoloration of the tooth involved.

It’ll be a good idea to wait for at least 2 weeks after the completion of root canal treatment before the start of the tooth whitening procedure. During this time period we should watch for the development of any symptom. If no symptoms arise then we should proceed for the tooth whitening procedure.

The temporary filling material used to fill the access cavity after the root canal obturation should be removed up to 3 millimeters beyond the cervical line.

Then, the remaining root canal filling material is covered by a setting calcium hydroxide paste of 1 millimeter thickness. The walls of the access cavity should be smoothed with the help of a dental bur. During smoothening procedure, a smear layer develops over the smooth surface of the cavity.

This smear layer should be removed from the walls of the access cavity. This is necessary otherwise the opening of the dentinal tubules will remain blocked and the tooth whitening chemical will not give its full effect. To do this, 37% ortho-phosphoric acid is applied over the surface of the access cavity and left for 20 seconds. It is rinsed thoroughly with water and air dried.

A cotton pledge, soaked in hydrogen peroxide or carbamide peroxide is placed inside the access cavity and sealed by a temporary filling material, e.g. zinc oxide eugenol cement.

It is left there for 2-3 or more days and continuously observed. The patient is instructed to report back when the color of the tooth becomes slightly lighter than the neighbouring tooth, the cotton pledge is removed from the access cavity and a suitable filling is done.

Teeth whitening of the vital teeth

Sometimes, few of us, especially younger ones think that the color of their teeth is yellow or grey, not the white. These days, beauty conscious people seek the help of teeth whitening procedure to lighten the teeth color and make it look whiter. This is done by “Vital Tooth Whitening Procedure”.

How it is done?

We shall tell you here.

Vital Teeth Whitening Procedure
  1. The original shade of the tooth is noted in the file.
  2. The shade guide is shown to the patient and the desired shade is also noted.
  3. A thorough scaling and polishing is done.
  4. All over the face, petroleum jelly is applied for protection from spill of etchant.
  5. Soft tissues are protected by protecting gel which is supplied by the manufacturer.
  6. The whitening agents are mixed as per manufacturer’s instructions and applied over the labial surfaces of anterior teeth, from canine to canine or from premolar to premolar.
  7. A light source is placed over it to enhance the chemical reaction.
  8. It is left there for the time period specified by the manufacturer.
  9. The whitening gel is washed away after the specified time.
  10. The color of the teeth are matched with the help of shade guide.
  11. If needed, the procedure is repeated again and again till the desired color is achieved.
  12. As a last step, the teeth, after washing away the whitening gal, are coated with a fluoride containing varnish.
  13. The patient is instructed for not eating or drinking anything, especially the carbonated drinks for one hour. This period is necessary for remineralisation of the enamel by calcium present in the saliva.
  14. Before patient leaves the dental office, (s)he is advised to avoid eating or drinking foods that may speed up the discoloration of the teeth.
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