Some people are born with teeth that are more yellow than others. Others have teeth that yellow with age. Your natural tooth colour can also be affected by many factors. Surface stains (called extrinsic stains by dentists) and discolouration can be caused by:
- Tobacco (whether smoked or chewed)
- Drinking coffee, tea, or red wine
- Eating highly pigmented foods such as cherries and blueberries
- Accumulation of tartar deposits, which result from plaque that has hardened
Internal stains (called intrinsic stains by dentists) can be caused by:
- Treatment with the antibiotic tetracycline during the time when teeth are forming
- Yellowing or greying of the teeth as part of the aging process
- Trauma to the teeth that may result in the death of the tooth's nerve, giving the tooth a brown, grey or black colour
What are Ways to Whiten Teeth?
Thorough cleanings by a dental professional will remove most external staining caused by food and tobacco. Using a whitening toothpaste can also help remove these surface stains between dental visits. If stains have been present for years, you may need to have your teeth professionally whitened to remove these more stubborn external stains.
Internal stains can be bleached, bonded or capped (crowned). While each of these methods is safe and effective, your dentist will recommend which treatment is appropriate for you depending on the state of your teeth and the results that you wish to achieve. Your dentist will consider:
- The degree and type of staining
- How much of the tooth structure is remaining (Is the tooth heavily filled? Are changes to the shape of the teeth needed or desired?)
How Does Bonding Work?
Bonding uses composite resins or porcelain/composite veneers to cover the surface of stained teeth and give a nice, even appearance to broken or misshapen teeth. There are two basic bonding techniques:
- Composite bonding First, the front of the tooth is slightly reduced to prevent the "new" tooth from being too bulky. Microscopic grooves are then etched into the tooth surface with a mild acid. A composite resin matched to the colour of the surrounding teeth is applied to the tooth, contoured into shape, set using a curing light, and finally smoothed and polished.
- Veneer bonding A veneer is made to match the colour and shape of your tooth. Porcelain veneers are generally stronger, while composite veneers are less expensive. With porcelain veneers, the dentist takes an impression of the tooth and sends it to the dental lab for fabrication of the veneer, usually after the front of the tooth has been reduced. With either method, the tooth is prepared for bonding by roughening the front surface with mild etching solution. The veneer can then be bonded to your tooth using a dental bonding cement.
While more expensive, a porcelain veneer offers a better colour match to your surrounding teeth and typically lasts for five to ten years.
Will My Newly Whitened Teeth Stain?
Any tooth can stain, including the veneers and bonds mentioned above. To help prevent stains from coming back, avoid smoking, coffee, tea, red wine and heavily coloured foods. And brush your teeth twice a day with a non-abrasive whitening toothpaste.
*The Complete Guide to Better Dental Care, Jeffrey F. Taintor, DDS, MS and Mary Jane Taintor, 1997.