A crossbite is a positional problem where a lower tooth meets the wrong side of the opposing upper tooth. Crossbites can involve a single tooth or a group of teeth. It can be classified as anterior or posterior, affecting either the back teeth or front teeth.

Causes for crossbite include hereditary factors, thumb sucking or trauma to the teeth or jaw.

There are several therapies that can be used to correct a cross bite which include: braces, quad helix, rapid palatal expanders (RMEs), and removable plates.
The correct therapy is decided by the orthodontist, depending on the type and severity of the crossbite.