The unilateral posterior functional crossbite: an opportunity to restore form and function.

The unilateral posterior crossbite (UPXB) with functional shift of the mandible is commonly encountered in young children and adolescents. Differential diagnosis and the impact this type of malocclusion might have upon the growth and development of dental and facial components are discussed. Impaired function and compromised facial esthetics may be consequences of untreated UPXBs with functional shifts. Appropriate treatment protocols and specific orthodontic appliances intended to correct these problems are presented.