Crossbites

Crossbite is a dental condition in which one or more of the upper teeth bite inside the lower teeth when the jaws are closed. It can involve the front teeth (anterior crossbite) or the back teeth (posterior crossbite). The problem may occur on one side (unilateral) or on both sides (bilateral) and can be caused by dental misalignment, skeletal jaw discrepancies, or a combination of both.

Causes of a crossbite include genetic factors that affect jaw size and tooth eruption, as well as environmental influences such as childhood habits (thumb sucking, prolonged pacifier use), mouth breathing, premature loss of primary teeth, crowding, and abnormal eruption patterns. Trauma to the teeth or jaws can also contribute. Crossbites may be present in the mixed dentition or become more pronounced as the permanent teeth erupt.

Diagnosis is made through a clinical examination of occlusion and jaw relationships, often supported by dental casts or digital scans. Imaging such as panoramic and cephalometric X-rays helps assess skeletal relationships and planning. In complex cases, further imaging may be used to evaluate the jaw joints and tooth positions.

Treatment depends on age, severity, and the underlying cause. In children, interceptive approaches aim to guide growth and eruption. These include palatal expansion (rapid or slow), which widens the upper jaw to correct posterior crossbites, and appliances or exercises to address anterior crossbites. In adults or in cases with skeletal discrepancy, orthodontic treatment with braces or aligners may be combined with orthognathic surgery to correct jaw relations. Retention and monitoring are important to prevent relapse.

Complications of untreated crossbites can include abnormal wear of teeth, uneven facial growth, temporomandibular joint pain, and functional or aesthetic concerns. Early detection and appropriate treatment generally lead to better outcomes.