No one wants yellow teeth. But knowing what types of stains are affecting your smile is the first step to making them go away. The types of stains on your teeth determine whether you would benefit from whitening. There are two types of stains: intrinsic, meaning deep within the tooth, and extrinsic, on the surface of the enamel. Most intrinsic stains do not benefit from whitening because bleach cannot penetrate far enough to reach interior stains, but extrinsic stains can be lightened with bleaching treatments.
With intrinsic stains, dentists will often recommend veneers, bonding or other forms of restoration that will cover the teeth to improve their appearance. These types of stains mainly occur during formation of permanent teeth in childhood, but they can develop in adulthood as well due to certain medications. But what causes intrinsic stains?
• Excessive fluoride. Known as hyperfluorosis, high concentrations of fluoride in water sources (while not harmful to the body) will be absorbed by teeth during enamel and dentin (the tissue beneath the enamel) formation. The result is an uneven mixture of colors from white to yellow and brown on the teeth. This type of stain is often resistant to whitening treatments and requires other means of correction such as bonding or veneers.
• Certain medications. If taken during tooth formation, the antibiotic tetracycline can cause deep blue-gray and, sometimes, yellow-brown stains on the internal structure of the teeth that cannot be removed by bleaching. Certain acne medications can have similar effects but tend to be a bit more subtle because of the even discoloration.
Extrinsic stains occur naturally over time as we consume pigmented food and drinks. You can prevent the worst of it by minimizing consumption of the biggest culprits. What causes extrinsic stains?
• Dark colored food and drinks. The most obvious culprit is also the most common. What we consume puts a constant barrage of stain-inducing particles on our teeth. Typically, the darker the pigment in the food (think berries and tomatoes) or drink (red wine, coffee, tea and soda), the more likely it is to stain the teeth.
• Tobacco. All types of tobacco and smoking, including chewing tobacco can dull and darken teeth.
• Poor dental hygiene. Bacteria can cause dental decay, periodontal disease and cause teeth to darken.
• Braces. Immediately after removal, there can be a difference in color between where the tooth was bonded and the part that was exposed to staining from foods and drinks. And, if not removed properly, braces can leave behind white spots on the teeth.