What is teeth whitening or teeth bleaching

 

Everyone wants to have whiter teeth. The idea that the teeth can be lightened and whitened in a simple way using a night guard, was a pioneering discovery. There are different techniques and agents available for tooth whitening. Materials for bleaching teeth have evolved over the past 200 years. There are primarily two types of bleaching techniques namely home bleaching and office bleaching technique.

What does a bleaching agent contain?

 

The constituents of a bleaching agent/ gel are:

  • Carbamide peroxide
  • Hydrogen peroxide and Sodium hydroxide
  • Non-Hydrogen peroxide containing materials - Sodium perborate
  • Thickening agents such as Carbopol or polyx
  • Urea
  • Vehicle - glycerine, dentifrice, glycol
  • Surfactants and pigment dispersant
  • Preservatives
  • Flavourings
  • Fluroides to reduce sensitivity

Are over the counter (OTC) bleaching kits safe?

 

OTC bleaching kits cause erosion of the tooth surface causing dissolution of the enamel and loss of tooth structure. Thus, it is best to avoid such products and rely on products prescribed by your dentist.

How long does it take to bleach the tooth?

 

There are various concentrations of the bleaching agent which allow for individulalized bleaching programmes for patients. Owing to the great variation in colour of the teeth being bleached, the bleaching time varies according to the existing shade of the teeth and the desired shade. A change in colour is noticed within 2 weeks of starting the bleaching procedure.

What are the causes of tooth staining or tooth discoloration?

 

Many researchers classify stainings as either extrinsic or intrinsic.

Extrinsic stains

  • Plaque, Chromogenic bacteria, surface protein denaturation
  • Mouthwashes, e.g. Chlorhexidine mouthwashes
  • Beverages, e.g. Tea, Coffee, Red wine, Cola
  • Foods, e.g. Curry, Cooking oils and fried foods, foods with colourings, Beetroot
  • Dietary precipitate
  • Illness
  • Antibiotics, e.g. Amoxicillins, Erythromycin
  • Iron supplements

Intrinsic stains

Pre-eruptive
  • Disease: Haematological diseases, Liver diseases, Diseases of Enamel and Dentine
  • Medication: Tetracycline stains, Fluoride stains, Other antibiotic stains
Post-eruptive
  • Trauma
  • Primary and Secondary caries (cavities/ decay)
  • Dental restorative materials
  • Ageing
  • Smoking
  • Chemicals
  • Minicycline
  • Some food stuffs (long-term use causes deeper intrinsic staining)
  • Functional and parafunctional changes