By Thomas J. Cangialosi, D.D.S.
Columbia University College of Dental Medicine

Sometimes an orthodontist will tell you that braces alone are not enough to correct the problems with your teeth. Extracting (removing) one or more teeth also may be part of the treatment plan.

But is it really necessary to extract teeth to correct a "bad bite," or malocclusion? It depends.

There are two main reasons for extracting teeth as part of orthodontic treatment. The teeth may be too crowded, or the front teeth may be positioned too far forward. Protruding front teeth are often referred to as "buck teeth."

First let's discuss crowding. This may result from excessively large teeth or from not having enough bone in your mouth to fit all the teeth. Crowding can be corrected in two ways. The dental arch can be expanded in order to fit all of your teeth, or certain teeth can be removed to provide more space for the others.

To help decide which of these alternatives would be best, the orthodontist or other dentist will take measurements using a special X-ray of the side of the head and face. This is called a cephalometric X-ray.

Expansion can be used only within certain limits. If the dental arch and jaw are expanded too much, the teeth tend to relapse back to their original positions. This occurs because of pressure from the muscles of the lips and cheeks.

Excess expansion also may create a problem of appearance. It may cause the teeth to come too far forward. The face then may appear too full. An overly large arch also may keep the lips from closing comfortably over the teeth.

If expansion will be excessive, then some permanent teeth usually have to be removed. The orthodontist will take careful measurements of the teeth. With the help of the special X-ray, the orthodontist can decide how much space is needed and which teeth to extract.

It is important to make sure that removing teeth will not bring the front teeth back too far. This could cause the face to appear too flat. Again, the cephalometric X-ray can indicate how much space is needed to correct the crowding. It also will show how far the teeth need to be brought back to get into a more normal position. Once this is achieved, any space remaining from the extractions can be closed by moving the back teeth forward.

Teeth that protrude or "stick out" are the other most frequent reason for extractions as part of orthodontic treatment. This condition can lead to more than just problems with appearance. It prevents the person from comfortably bringing the lips together over the teeth. This leads to mouth breathing, which may be harmful to both the teeth and the soft tissues of the mouth and throat.

Protruding can occur with upper teeth, lower teeth or both. If it is extreme, permanent teeth may have to be removed so the front teeth can move back into a normal position. The teeth that are removed most often are either the first or second bicuspids.

But removing teeth is not always required. In some cases, there may be spaces between some teeth. This provides room in the mouth that can be used to bring the front teeth back. In these cases, removing permanent teeth may not be necessary.

In children who are still growing, sometimes the entire upper dental arch may be moved back by using a headgear appliance (sometimes called a night brace). This can move the back teeth back to allow the front teeth to move into a normal position.

So are tooth extractions for orthodontic treatment necessary? The answer is "sometimes."

This decision must be made on an individual basis. The orthodontist will thoroughly analyze X-rays, photographs and models of the teeth. Then he or she will recommend extractions — or none — for each patient based on all of this information. In most orthodontic offices today, extraction of permanent teeth is required in about 20% to 25% of cases treated.

Thomas J. Cangialosi, D.D.S., an orthodontist, is professor and chairman of the Section of Growth and Development and director of the Division of Orthodontics at the Columbia University College of Dental Medicine. He has been on the faculty for 33 years. Dr. Cangialosi was past chairman of the Council on Orthodontic Education of the American Association of Orthodontists. He is also a consultant to the New York State Children's Rehabilitation Program. He served an eight-year term as a director of the American Board of Orthodontics and was its president in 2003 and 2004. He currently serves as a consultant to the board.