Teeth become discolorised by stains on the surface or by changes in the tooth material. It is most inevitable that our teeth become discolored as we age. As cosmetic and aesthetic dentistry gain in popularity, however, the treatments for stained and yellow teeth are more effective and more accessible to everyone.
Teeth become discolored as a result of many different things- some of which are more avoidable than others. The surface of the teeth has microscopic cracks which absorb stain. The whitening process draws the discoloration out of the teeth to leave a brighter and whiter appearance.
Dentists divide discolorization into three main categories:
- Extrinsic discoloration- This occurs when the outer layer of the tooth (enamel) is stained. Coffee, wine, cola or other drinks or foods can stain teeth. Smoking also causes extrinsic stains.
- Intrinsic discoloration- This is when the inner structure of the tooth (the dentin) darkens or gets a yellow tint.
- Age-related discolorization- This is a combination of extrinsic and intrinsic factors. Dentine naturally yellows over time. The enamel that covers the teeth gets thinner with age, which allows the dentin to show through. Foods and smoking also can stain teeth as people get older. Also, chips and other injuries also can discolor a tooth especially when the pulp has been damaged.
Some of the most common causes include:
- Diet. Strong colors in foods will discolor the teeth. It advisable to avoid or limit such things as coffee, tea, red wine, some heavily spiced foods such as curries and foods with high pigment concentrates such as balsamic vinegars, soy sauces and strongly colored fruit drinks. Food and drink with a high acid or sugar content affects tooth discolorization. Very hot or very cold food and drink will cause fine cracking of the tooth enamel, which will allow pigments to penetrate the tooth surface and cause staining.
- Smoking. This is a leading cause of excessive tooth staining. In smokers, the tooth enamel is constantly subjected to dark colored particles from cigarette smoke, which can build up and create deep yellow and brown stains in the teeth.
- Medications. Certain drugs such as tetracycline taken during childhood when the permanent teeth are developing have been known to cause deep staining of the teeth, similar to that from an injury.