DON’T END UP CROSS ABOUT CROSSBITES

Crossbites are a common form of malocclusion (tooth misalignment) that is estimated to happen in up to 20% of people. A crossbite occurs when one or more of the maxillary (top) teeth don’t fit properly over the mandibular (bottom) teeth. The outer edges of the top teeth should always fit just over the bottom teeth, like a shoe box lid fitting snugly over a shoebox. A “posterior crossbite” is the type that involves one or more of the back teeth on top tooth being “inside” of the bottom teeth. An “anterior crossbite” is when one or more of the front teeth on top are “behind” those on the bottom, commonly known as an “underbite”.

Some common causes of crossbite result from both genetic and developmental factors and include having a narrow upper jaw, an adult tooth that erupts in an abnormal position, or crowding of the teeth. Because a tooth in crossbite is not in the right position, the tooth often hits harder or before the others when biting down. This is recognized by little “sensors” (proprioceptors) surrounding the tooth which signal that the bite is off. Trying to find a more comfortable and stable bite, the body sometimes moves the lower jaw position to one side or the other, which is called a functional shift. In children who are growing, a functional shift can result overtime in one side of the jaws growing faster relative to the other, causing skeletal asymmetry.

Because of the side effects of dental wear and developing permanent skeletal asymmetries, orthodontists typically like to correct crossbites as early as possible once kids have permanent teeth (usually any time after six to seven years old). Pediatric dentists can do it even earlier at 4-5 years of age. Posterior crossbites are typically the result of a narrow upper jaw and can easily be fixed with a palate expander in children whose palate isn’t yet fully fused and is therefore easily malleable. Single tooth anterior crossbites can sometimes be corrected with bite ramps, while multiple teeth will typically require braces. Crossbites are fairly common, but they can lead to serious problems if not addressed and the treatments can become more challenging after childhood. If you notice anything unusual about your child’s or your own bite, please schedule a visit to our office so we can discuss the issues and determine if any treatment is indicated.