What Is It?
Your teeth can become discolored by stains on the surface or by changes in the tooth material. Dentists divide discoloration into three main categories:
- Extrinsic discoloration — This occurs when the outer layer of the tooth (the enamel) is stained by coffee, wine, cola or other drinks or foods. Smoking also causes extrinsic stains.
- Intrinsic discoloration — This is when the inner structure of the tooth (the dentin) darkens or gets a yellow tint. Causes include excessive exposure to fluoride during early childhood, the maternal use of tetracycline antibiotics during the second half of pregnancy and the use of tetracycline antibiotics in children 8 years old or younger.
- Age-related discoloration — This is a combination of extrinsic and intrinsic factors. In addition to stains caused by foods or smoking, the dentin naturally yellows over time. The enamel that covers the teeth gets thinner with age, which allows the dentin to show through. Chips or other injuries to a tooth can also cause discoloration, especially when the pulp has been damaged.
In rare cases, children with a condition called dentinogenesis imperfecta are born with gray, amber or purple discolorations.
Symptoms include stains on the enamel or a yellow tint in the dentin.
No special tests are needed. A dentist can diagnose tooth discoloration by looking at the teeth.
Some tooth discoloration can be removed with professional cleaning, but many stains are permanent unless the teeth are treated (whitened) with a bleaching gel.
Brushing your teeth after every meal will help to prevent some stains. Dentists recommend that you rinse your mouth with water after having wine, coffee or other drinks or foods that can stain your teeth. Regular cleanings by a dental hygienist also will help to prevent surface stains.
Intrinsic stains that are caused by damage to a nerve or blood vessel in the inner part (the pulp) of a tooth sometimes can be prevented by having root canal treatment, which removes organic material before it has a chance to decay and darken. However, teeth that undergo root canal treatment may darken anyway. To prevent intrinsic stains in children, avoid water that contains a high fluoride concentration. You can check the concentration of fluoride in your drinking water supply by calling the public health department. Then consult your dentist.
Discoloration often can be removed by applying a bleaching agent to the enamel of the teeth. With a technique called "power bleaching," the dentist applies a light-activated bleaching gel that causes the teeth to get significantly whiter in about 30 to 45 minutes. Several follow-up treatments may be needed.
It's also possible to remove discoloration with an at-home bleaching gel and a mouth guard given to you by your dentist. The bleaching gels designed for use at home aren't as strong as those applied by your dentist, so the process takes longer — usually two to four weeks. Whitening toothpastes may remove minor stains, but they aren't very effective in most cases.
If you've had a root canal and the tooth has darkened, your dentist may apply a bleaching material to the inside of the tooth.
When a tooth has been chipped or badly damaged or when stains don't respond to bleaching, your dentist may recommend covering the discolored areas. This can be done with a composite bonding material that's color-matched to the surrounding tooth. Another option is to get veneers, which are thin shells of ceramic that cover the outer surfaces of the teeth.
When To Call a Professional
Tooth discoloration is mainly a cosmetic problem. Call a dentist if you're unhappy with the appearance of your teeth. Any change in a child's normal tooth color should be evaluated by a dentist.
The prognosis is very good for extrinsic stains. Intrinsic stains may be more difficult or take longer to remove.