Tooth Stains That Don't Respond To Bleaching: What To Do About Intrinsic Discoloration

Tooth bleaching is one of the most common ways for people to improve the appearance of their teeth. Bright white teeth can make any smile seem more attractive, and the procedure is simple, whether it's done through at-home whitening strips or professional bleaching by a dentist.

However, if you have tooth stains that haven't responded to whitening, you should know that you're not alone. Bleaching is very effective for people with stains on the enamel of their teeth, such as those caused by smoking or drinking staining drinks like coffee; this is extrinsic discoloration. But there's another category of tooth discoloration called intrinsic discoloration.

What is intrinsic discoloration?

If extrinsic discoloration is discoloration of the surface enamel of the teeth, intrinsic discoloration is the opposite: discoloration within the tooth. Specifically, it happens when the dentin – the layer right below the enamel – becomes stained or discolored. Since the enamel on teeth is translucent, this shows through and may look like stains on the surface of the tooth.

What causes intrinsic discoloration?

There are a few causes for discoloration within teeth. It can be a hereditary problem, so if your family has many people with stained teeth, this may be the case. Certain antibiotics, like tetracycline and doxycyline, can cause intrinsic discoloration when taken by children, and overexposure to fluoride during childhood can also cause staining.

For staining that begins during adulthood, other medications may be to blame; the possible causes range from antihistamines to antipsychotics, so discuss your medical history with your dentist if you suspect you may have this type of staining.

And finally, injuries and disease within teeth can cause intrinsic discoloration. Decay within the root or pulp of the tooth may lead to discoloration of the dentin; for this reason, if you notice new discoloration, it's important to bring it up with your dentist so you can check for any underlying dental problems.

What can be done about intrinsic discoloration?

Since the discoloration is under the surface of the teeth, surface bleaching is not usually effective in treating intrinsic discoloration. Instead, the best way to get rid of intrinsic stains is to mask them by covering the surface of the teeth, either with bonding or veneers.

Bonding means applying tooth-colored resin to the surface of your teeth. It is sometimes used to fix small chips and other cosmetic issues in teeth; because the resin is matched to the color of your teeth, it can also be used to cover discoloration. The surface of the tooth must be roughened slightly, which means removing some enamel; however, less is removed than for veneers. The bonding will also wear down over time and must be kept touched up by your dentist.

Veneers are thin shells of porcelain or resin that are attached to the fronts of your teeth. They are stronger than bonding and last longer without wearing down, but more enamel must be removed to attach them, so they may not be a good option for people with worn enamel. A cosmetic dentist can help you decide which treatment is a better choice for your teeth.