Are braces effective for treating crossbite (top back teeth biting down inside the bottom back teeth)?

Posterior crossbite occurs when the top teeth or jaw are narrower than the bottom teeth. It can happen on one side or both sides of the dental arches. This condition may increase the likelihood of dental problems (e.g. tooth wear), abnormal development of the jaws, joint problems, and unbalanced facial appearance. Posterior crossbites affect around 4% and 17% of children and adolescents in Europe and America. 

Different treatment approaches have been proposed, resulting in many different braces being produced. The basic treatment to correct crossbite correction treatment involves using an orthodontic device on the palate (roof of the mouth) to expand the upper jaw by exerting pressure on both sides of the jaw. The devices can be fixed (e.g. quad‐helix, Haas, Hyrax expander) or removable (e.g. expansion plate). Fixed appliances are bonded to the teeth, while removable devices can be taken out of the mouth by patients.

Orthodontic treatment for correcting posterior crossbites

Photo copyright Giorgio Fiorelli

Posterior crossbite is when the top back teeth bite down inside the bottom back teeth. It occurs when the top teeth or jaw are narrower than the bottom teeth and can happen on one or both sides of the mouth. The condition affects between 1% and 16% of children who only have their baby teeth. Most posterior crossbites (50% to 90%) remain even when the permanent teeth erupt. In a minority of children, the problem self-corrects.

In order to obtain a more comfortable bite, the lower jaw shifts to one side into a position that allows more teeth to come into contact. However, this shifting of the lower jaw may lead to tooth grinding, and this may lead to other dental problems including the tooth surface being worn away, abnormal growth and development of the teeth and jaws, and jaw joint problems.

Therefore, we need to find safe and effective treatments to correct posterior crossbites or expand the top back teeth, or both. One way of doing this is using orthodontic treatments. This can be more effective in children because the two halves of the roof of the mouth have not fully joined yet, so the top back teeth can be expanded more easily. Orthodontic treatments can also be used to treat posterior crossbites in adults, but they are more likely to need surgical treatments, which are not the focus of this review.