Crossbites

Definition
Causes
Solution

Definition

In a typical dentition, whether primary or permanent, the buccal cusps of the upper posterior teeth align with the buccal aspect of the lower teeth, while the lingual cusps of the upper posterior teeth correspond with the occlusal surface of the lower teeth. Additionally, the upper anterior teeth typically overlap the labial surface of the lower anterior teeth.

When these relationships are disrupted in fully erupted teeth, one or more teeth may be in a state of "crossbite." An anterior crossbite occurs when the malocclusion involves anterior teeth, whereas a posterior crossbite involves posterior teeth. Crossbites can further be classified as unilateral when occurring on one side of the dental arches, and bilateral when present on both sides.

However, when upper and lower cusp tips occlude tip-to-tip but shift functionally to the right or left upon full closure, resulting in a misleading appearance of a crossbite, it is termed a "pseudocrossbite" and is not considered a true crossbite.

Causes

Crossbites may arise due to a mal-posed tooth or teeth, leading to a "dental crossbite", or as a consequence of a severely narrow or horizontally mispositioned maxilla or mandible, termed a "skeletal crossbite".

Solution

Treatment for crossbites varies depending on the underlying cause. Dental crossbites may be corrected through dental expansion procedures and tooth movement appliances like clear aligners or braces.

Removable aligners are particularly effective in correcting dental crossbites. They provide a barrier between the upper and lower arches, allowing the affected teeth to move without interference from opposing teeth.

Alternatively, fixed braces may incorporate turbos or bite blocks to separate the arches during correction and reduce occlusal collisions.

Correction of skeletal crossbites necessitates skeletal expansion and/or surgical intervention to address the underlying skeletal discrepancies before tooth repositioning.