Kryssbitt

Kryssbitt, known in English as crossbite, is a dental malocclusion in which the upper teeth bite inside the lower teeth when the jaws close. It can involve one or more teeth and may affect the front teeth (anterior crossbite), the back teeth (posterior crossbite), or both. Crossbites can be unilateral, affecting one side, or bilateral, affecting both sides.

Causes are often multifactorial. Genetic factors can influence the width of the upper and lower jaw, while abnormal jaw growth during childhood can create a mismatch. Habits such as prolonged thumb sucking, tongue thrust, or airway problems leading to mouth breathing can contribute. Early loss of baby teeth or crowding of the teeth may also predispose a crossbite.

Diagnosis is based on clinical examination and imaging. A clinician assesses the occlusion, takes dental impressions or scans, and may use X-rays to evaluate tooth position and jaw relationships. If untreated, crossbites can cause uneven wear, tooth grinding, gum recession, and abnormal jaw development, and may contribute to temporomandibular joint symptoms.

Treatment depends on age and severity. In children, interceptive approaches aim to guide growth and include palatal expanders to widen the upper jaw, braces, or removable appliances. Elastic bite mechanics may correct anterior crossbite. In adults, orthodontic treatment with braces, clear aligners, or surgical procedures may be required to correct skeletal discrepancies. Retention with retainers is often needed to prevent relapse. Addressing contributing factors such as breathing problems or tongue posture may improve long-term stability.

Prevalence is relatively common among children and is typically more noticeable during dental development. Early diagnosis and intervention improve outcomes.