An underbite occurs when the lower front teeth are positioned ahead of the upper teeth. It can be caused by a congenital misalignment of the lower jaw or caused by the patient voluntarily posturing the lower jaw ahead of the upper teeth. In either instance, the resulting underbite can make eating and speaking challenging, and cause other serious problems. An expander may be used to expand the upper jaw along with a protraction device of the upper jaw until the lower teeth no longer close ahead of the upper teeth. Skeletal issues such as an underbite are the main reasons why the American Association of Orthodontists recommends a child to receive an orthodontic consultation at the age of 7.