Braces are dental devices designed to move crooked, crowded or misaligned teeth into proper position. These stainless steel, ceramic or plastic devices are placed on the teeth. They apply light pressure to the teeth over long periods of time. As this pressure is applied, the teeth gradually shift into a more normal alignment.

Braces are a treatment associated with a specialy of dentistry called orthodontics. Orthodontics focuses on malocclusion, a term that means “bad bite.” Braces are used to correct improper alignment of the teeth in order to straighten teeth, correct a bite, close gaps in the teeth, or bring the teeth and jaw into proper alignment. About 6 million people in the United States and Canada receive orthodontic care each year, according to the American Association of Orthodontists.

Malocclusion causes a variety of problems with the teeth and jaws. Some of the most common include:

• Crossbite. The most common type is when the upper teeth sit inside (rather than outside) the lower teeth during biting. This can cause biting and chewing problems.
  
  
• Crowded or crooked teeth. Poor alignment of teeth can occur as the result of a dental arch that is too small, teeth that are too large or a combination of these factors. Teeth may become impacted or a patient’s bite may be affected. Crowded or crooked teeth also can be cosmetically unappealing.
  
  
• Open bite. Occurs when upper and lower incisor teeth do not touch during biting. This places all chewing pressure on the back teeth, making chewing less efficient and causing excessive wearing of the teeth.
  
  
• Overbite. The upper jaw is larger than the lower jaw, leading to discomfort, bone damage and excessive wear of the front teeth.
  
  
• Protruding upper teeth. These teeth are more prone to injury and may indicate unevenness in jaw growth. They also may indicate a poor bite of the back teeth.
  
  
• Spacing. A wide dental arch, missing teeth or teeth that are small can cause gaps between the teeth, which may be considered cosmetically unappealing.
  
  
• Underbite. When the lower jaw is bigger than the upper jaw, resulting in lower front teeth that protrude and a possible crossbite.

In most cases, malocclusions are genetic. However, some can be acquired through certain situations, including:

• Accidents. Teeth that are fractured or knocked out may fuse with the bone around them (ankylosis) following replacement. This prevents the teeth from lining up properly in the jaw of a growing child, resulting in an irregular bite.
  
  
• Illness and other problems. Conditions that develop after birth (e.g., air obstruction due to swollen tonsils or adenoid) can cause malocclusions.
  
  
• Prolonged thumb sucking or use of a pacifier. Children who engage in either of these habits after their permanent teeth erupt (about age 6 or 7) can force the upper teeth to protrude over the lower teeth.
  
  
• Premature loss of baby teeth. When a primary tooth is lost too early, it can cause the emerging permanent tooth to drift or erupt incorrectly. In some cases, adjacent primary teeth may move into the gap left by the tooth that was lost early. This can prevent the permanent tooth from coming in.
  
  
• Tongue-thrusting. A habit of pushing the tongue onto the back of the front teeth during swallowing can cause the teeth to protrude.

Braces can help correct many of these dental problems. Malocclusions are most often corrected for cosmetic reasons, such as improving one’s appearance with aligned teeth or a more exact bite.

Braces may also be used to correct medical or dental problems related to malocclusions, such as improving a person’s ability to chew or to talk. For example, straightening a patient’s teeth may prevent or correct:

• Abnormal wear of teeth (including accidents such as chipped teeth)
  
  
• Stress on gum tissue and bone that supports the teeth
  
  
• Misalignment of the jaw (which can trigger headaches and neck or facial pain)

Braces can be an extremely effective treatment for straightening a patient’s teeth or correcting a misaligned bite. However, braces can cost several thousand dollars, and insurance may only cover part of the cost. Some plans do not cover any of the cost.