A posterior crossbite occurs when the back teeth fit incorrectly inside the lower teeth. This can happen on one or both sides of the mouth. There are many reasons why a posterior crossbite occurs but often it is due to a narrow upper jaw.

Posterior Crossbites in Children

In a growing child, a posterior crossbite can have serious detrimental consequences. The crossbite can make the lower jaw shift incorrectly to one side, causing the bite and face to be asymmetric temporarily. If the lower jaw is kept in this position and not corrected, growth can continue in this direction resulting in a permanent facial asymmetry. The permanent facial asymmetry can only be treated by jaw surgery.

A narrow upper jaw is usually treated with a palatal expander. An expander has a screw in the centre, which is turned according to a schedule we provide you. As the screw is turned, the palate becomes wider.

Expanders only work in children/early teenagers so it is important that you visit an Orthodontist during this time. We recommend that a child go for his/her first orthodontic consult around the age of 7. Call our Vaughan office to learn more about this and to book your free orthodontic consultation.

Posterior C


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