There is a lot of information out there about dental bleaching and tooth whitening. Let’s look at this interesting topic and try to get a better understanding of what it is, the options for bleaching and whitening, what it can and cannot do, and when it is indicated or contraindicated. It is important to understand that the natural tooth color can vary greatly from individual to individual, sort of like skin color but not as dramatically. Some people are blessed with naturally white teeth, while some of us suffer from a less cosmetic darker enamel color. Naturally whiter teeth will darken with time and age, and can get much darker when a person smokes, drinks coffee, or consumes foods, drinks, and condiments that promote staining.
First; what is dental bleaching or tooth whitening, and is there a difference between tooth whitening and dental bleaching? There is a significant difference between tooth whitening and bleaching. There are 2 (two) types of tooth discoloration and whitening addresses one while bleaching addresses the other. Teeth can change color and become darker due to either extrinsic staining or intrinsic staining or discoloration.
Extrinsic stains affect the surface of the tooth and are often associated with a pelical or coating on the surface of the tooth rather than being a superficial surface stain of the tooth itself. The tooth itself can discolor, but the enamel is so hard that it is relatively difficult to stain the tooth and it usually takes significant time and consistent staining to discolor the enamel. Regardless of whether or not the tooth surface itself is discolored, extrinsic staining is superficial and affects only the very surface of the tooth and the tooth itself maintains its natural color. If the staining is extrinsic, the tooth can be whitened by removing the superficial staining. This is called tooth whitening, and the internal, natural color of the tooth is not changed, but the superficial staining is removed allowing the natural, lighter color to show.
Superficial stains can be removed by cleaning the tooth surface. Sometimes this can be done with a toothbrush and whitening toothpaste, other times a more aggressive approach is required. Oftentimes, your dental hygienist can remove superficial stains when you get your teeth cleaned. If this is unsuccessful, there are other chemicals and mild abrasives that can be used to remove the superficial stains and restore the lighter natural tooth color. This is best done in your dentists office rather than over the counter because the abrasives may remove significant tooth structure if overdone and not managed properly.
Intrinsic stains or discolorations are embedded deeper in the tooth structure and are not able to be whitened with regular tooth whitening methods or superficial cleanings. They require a color change in the underlying tooth structure, and this is done by bleaching. The bleaching can be done from either the surface of the tooth or from within the tooth itself through the root canal. The bleaching chemicals change the color off the tooth itself and remove some of the natural tooth color.
An example of when internal bleaching would be done is when dental trauma causes the tooth color to change. With trauma, the blood vessels in the root canal can bleed into the inside of the tooth, essentially doing the same thing as a bruise which discolors the skin because of the bleeding underneath. The difference is that this bruise inside the tooth is difficult for the body to clean up and the small tubioles inside the tooth can fill with blood which the body is unable to remove, so it stains the tooth and turns it a dark color that may appear gray. In these cases, a superficial bleaching may not be as successful as desired.