Braces: Not Just for Looks, Causes of Crooked Teeth

by Food and Drug Administration (FDA)

"Heavy metal bands" may conjure up images of rock music today, but many baby boomers remember them as the clunky and conspicuous devices they wore in their mouths as children to straighten their teeth.

Today's braces are a lot different from the metal-mouth look of a generation ago. "They're more aesthetic and more efficient," says Donald Joondeph, D.D.S., an associate professor of orthodontics at the University of Washington in Seattle. And they're more comfortable to wear and better at repositioning teeth, he adds.

Braces used to be put on only after all the permanent teeth came in. Today, a multitude of dental devices, or orthodontic appliances, are being used at an early age to simplify later treatment, provide a better outcome, and, in some cases, avoid braces altogether. Adults, who make up one-fifth of orthodontic patients, also are opting for straighter teeth as more choices in orthodontic appliances become available.

About 4.5 million people in the United States are wearing braces or other appliances to achieve a beautiful smile and healthy teeth, according to the American Association of Orthodontists (AAO). These appliances are regulated by the Food and Drug Administration to assure their safety and effectiveness.

Not Just for Looks

Braces are more than the means to a stunning smile — they can improve dental health and function, says Susan Runner, D.D.S., chief of the Dental Devices Branch in the FDA's Center for Devices and Radiological Health. "They can be used to move teeth that are overcrowding," Runner says. Crowded or crooked teeth are harder to brush and floss, and improper cleaning can lead to tooth decay and other dental problems.

"Braces can correct severe bite problems that would hamper eating and give a greater risk of gum disease and tooth and bone loss," says Runner. Bite problems may occur when the upper and lower jaw don't come together properly. Uncorrected bite problems can cause teeth to wear down, make for difficult chewing, and put stress on the jawbone, producing pain.

Causes of Crooked Teeth

Most people do not have naturally straight teeth; in fact, the AAO estimates that up to 75 percent of people could benefit from orthodontic care.

Heredity and environmental factors are the two causes of crooked teeth and bite problems, says Terry Pracht, D.D.S., president of the AAO and an orthodontist in Westerville, Ohio. Crowding of teeth, too much space between teeth, and upper teeth that don't match lower teeth when biting down are usually inherited. But jaw-jolting accidents, as well as habits such as tongue thrusting and thumb sucking, can cause crooked teeth.

Tongue thrusting is the abnormal tendency to push the tongue onto the back of the front teeth during swallowing, causing the teeth to protrude over time.

Thumb sucking is normal in young children and isn't an orthodontic problem unless it persists when the permanent teeth come in, says Pracht. "If a child is still thumb sucking at about age 7 when the upper front teeth start to erupt, it can not only affect the teeth, but the shape of the jawbone," he says.

Then and Now

Braces work by putting pressure against the teeth, moving them gradually over time. Most of the pressure is applied by a metal wire, called an archwire, that runs on the outside of the teeth. "Rubber" bands, actually made from surgical latex, put additional pressure on the teeth that the archwire alone cannot do.

Earlier types of braces had an archwire connected to large metal bands that were individually wrapped and cemented around each tooth. "The metal bands were uncomfortable," says Pracht, adding that it used to hurt to have braces put on and adjusted. "There was a lot of pushing and shoving."

Today, the archwire is attached to tiny brackets made of metal or ceramic. The brackets are bonded with a glue-type agent to the front of the teeth. Some of the bonding agents continuously release fluoride to help protect the enamel of the teeth underneath the brackets. Metal bands may still be used on the back teeth, but they are smaller and lighter than bands used previously.

The archwire requires periodic adjustment or replacement by the orthodontist to apply continuous pressure. Today's archwires are active over longer periods of time, meaning patients don't have to visit the orthodontist as often to get their braces adjusted. "It used to be every three to four weeks; now it's every six to eight weeks," says Pracht. And archwires are much gentler. "There is some sensitivity when eating for only a day or two after an adjustment."

Archwires now are made from a heat-activated, nickel-titanium mixture originally developed by NASA to activate solar panels of spacecraft in orbit. At room temperature, the wires are very flexible, allowing them to be attached to the teeth more easily. When they warm to mouth temperature, they apply gradual and constant pressure on the teeth.

Today's braces come with more options to make them less obvious — or, if a person chooses — more obvious, with an element of fun and fashion. Most of Pracht's adult patients opt for clear or tooth-colored brackets. "They are not apparent from a distance and not very noticeable up close," he says. Some people choose gold braces. "One company markets them as jewelry for the mouth," says Pracht.

Colors are especially popular with children and teens, who will often choose the colors of their school, a favorite sports team, or holiday colors, such as pink and red for Valentine's Day and orange and black for Halloween. The colors are mainly on the elastic ties that attach the archwire to the brackets, and they can be changed when the archwire is adjusted. Archwires and rubber bands also come in a variety of hues.

About the Author

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FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.