What causes teeth to stain and discolor?

At any one point in a person's life the color of their teeth can and will be influenced by a number of different factors. And because this range of tooth staining influences exists, before the use of an at-home tray teeth whitening (teeth bleaching) system is initiated it is important for the person's dentist to evaluate the possible causes of their tooth discoloration. Having an idea of the nature of the staining allows the dentist to determine if teeth whitening treatments are an appropriate method by which to resolve it and to estimate how much lightening effect the teeth whitening treatments might be expected to achieve.

All teeth have an inherent baseline color.

Simple observation of those around us quickly reveals that the teeth of humans, collectively as a race, display a wide range of different shades of white. There is no one specific color that a person's teeth are supposed to be, or should be. Some people's teeth are just naturally lighter, or darker, in color than others.

As evidence of this variability, if you have ever had a dental crown, a porcelain veneer, or tooth bonding placed you have probably noticed that at some point during the procedure the dentist will compare the color or your teeth to a "shade guide." A shade guide is a sampling of the various shades of white the particular dental material your dentist is working with is manufactured in. Manufacturers make their products in a range of shades because they realize that there is no one color that teeth are expected or supposed to be.

• Lightening the baseline color of a person's teeth may be a difficult task to achieve.

It is normal that teeth will discolor with age.

It is to be expected that with age the shade of a person's teeth will darken. This is because great deal of what we visualize as the color of a tooth stems from the play of light as it passes through a tooth's translucent outer layer (its enamel) and then reflects back out once it has struck the opaque inner structure of the tooth (the tooth's dentin) that lies underneath. Any circumstances that alter the properties of these tooth tissues (enamel and dentin) can have an effect on the color of a tooth.

With age it is commonplace that the thickness of a tooth's enamel will become thinner, thus revealing more of the (darker) dentin that lies underneath. The color of a tooth's dentin also tends to change over time. It's color typically becomes darker as a tooth's normal physiologic and reparative processes create more of it (secondary dentin).

• Age related tooth staining often resolves favorably with teeth whitening treatments.

Discoloration can occur because of exposure to chromogenic agents such as tea, coffee, red wine, colas, and tobacco products.

Exposure to chromogenic agents such as tea, coffee, colas, red wine and tobacco products can have a staining effect on teeth. Regular users of these types of products will often notice that their teeth have taken on a dingy or yellow tint. In more severe cases this type of staining can take an orange or even brown coloration. The amount of tooth staining that occurs can often be correlated, at least to some degree, to the regularity or relative degree of exposure the person has had to specific chromogenic agents over the years.

• Tooth staining caused by exposure to chromogenic agents often resolves quite favorably with teeth whitening treatments.

A systemic exposure to certain types of medicines can cause tooth staining.

Some types of tooth staining are caused by a systemic exposure to certain medicines. The typical theme associated with this type of staining is that the offending compound is ingested during childhood during that time frame when teeth are forming. The compound subsequently becomes incorporated into the tooth's mineralized tissues (enamel and/or dentin) as they are formed, thus affecting the tooth's color.