One or more of the upper teeth biting on the inside of the lower teeth characterizes a crossbite. Crossbite can occur in the front and/or the sides of the mouth. Early correction of crossbites is recommended. Crossbites should be corrected because they can: Cause premature wear of the teeth Cause gum disease including bone loss Cause asymmetrical development of the jaws Cause dysfunctional chewing patterns Make your smile less attractive Be related to jaw joint dysfunction (TMJ)