A crossbite is a type of malocclusion, or a misalignment of teeth, where upper teeth fit inside of lower teeth. This misalignment can affect a single tooth or groups of teeth, involving the front teeth, back teeth, or both. There are two types of crossbites:

• Posterior crossbite: If the back teeth are affected, upper teeth sit inside of bottom teeth.

• Anterior crossbite: If the front teeth are in crossbite, one or more top teeth sit behind the bottom teeth. Not to be confused with an underbite, when all the top teeth, or jaw, are behind the bottom teeth.

A crossbite can be caused by either tooth position, jaw position, or a combination of both. Genetics is the most frequent reason for crossbite in children, but it can also be caused by the persistent use of a pacifier, nail biting, poor chewing habits, or thumb sucking. It can also be caused by the delayed loss of primary teeth, having large tonsils or adenoids, or a narrow upper jaw and palate.

A crossbite can cause irregular wear and damage to teeth, jaw growth problems in growing kids and teens, bite and breathing issues, and tooth chipping or gum problems if left untreated. In rare cases, it can lead to Temporomandibular Joint Disorder (TMD), which can result in earaches, jaw pain or discomfort, headaches, as well as jaw problems in the muscles.

Treatment for a crossbite depends on the severity and where the teeth are affected. In kids and teens, posterior crossbites are often treated by broadening the upper teeth and jaw with special appliances or braces. Crossbites of front teeth are many times treated with braces or special retainers. In some teens and adults, crossbites can be treated by braces or Invisalign treatments. In rare cases, crossbites are so severe that jaw surgery may be needed. It is important to consult an orthodontist to determine the best course of treatment for a crossbite.