Posterior Crossbite

A crossbite is a discrepancy in the buccolingual relationship of the upper and lower teeth. Crossbite can be seen commonly in orthodontic practice. It can be clinically identified when the lower teeth are in a buccal or labial position regarding the upper teeth in a unilateral, bilateral, anterior, or posterior manner. In the transverse dimension, normal occlusion is when the palatine cusps of the upper molars and premolars occlude in the fossa of the lower molars and premolars. In the anteroposterior plane, the upper incisors occlude on the labial aspects of the lower incisors. The term buccal crossbite refers to the buccal cusps of the lower teeth, which are occluding buccal to the buccal cusps of the upper teeth. Scissor bite refers to the condition when the buccal cusps of the lower teeth occlude lingual to the lingual cusps of the upper teeth. Crossbite malocclusion can have a skeletal or dental component or a combination.