Correction of unilateral posterior crossbite in the mixed dentition. Studies of treatment effects, stability and cost-effectiveness.

Unilateral posterior crossbite of dento-alveolar origin is a transverse discrepancy of the maxillo-mandibular relationship and is one of the most common malocclusions in the mixed dentition. If untreated, the crossbite and the abnormal lateral movement of the lower jaw may strain the orofacial structures, causing adverse effects on the temporomandibular joints, the masticatory system and facial growth. Thus, early orthodontic intervention is usually undertaken to correct the condition at the mixed dentition stage and the orthodontist may choose from a range of treatment methods. The method of choice for orthodontic treatment should not only be clinically effective, with long-term stability, but also cost-effective. The overall aim of this thesis was to compare and evaluate different methods of correcting unilateral posterior crossbite, in terms of clinical effectiveness, stability and cost-effectiveness. The approach was evidence-based; randomized controlled trial (RCT)-methodology was used in order to generate a high level of evidence.