Fixed or removable appliance for early orthodontic treatment of functional anterior crossbite : evidence-based evaluations of success rate of interventions, treatment stability, cost-effectiveness and patients perceptions

Anterior crossbite with functional shift also called pseudo Class III isa malocclusion in which the incisal edges of one or more maxillaryincisors occlude with the incisal edges of the mandibular incisorsin centric relationship: the mandible and mandibular incisors arethen guided anteriorly in central occlusion resulting in an anteriorcrossbite.Early correction, at the mixed dentition stage, is recommended,in order to avoid a compromising dentofacial condition whichcould result in the development of a true Class III malocclusionand temporomandibular symptoms. Various treatment options areavailable. The method of choice for orthodontic correction of thiscondition should not only be clinically effective, with long-termstability, but also cost-effective and have high patient acceptance, i.e.minimal perceived pain and discomfort. At the mixed dentition stage,the condition may be treated by fixed (FA) or removable appliance(RA). To date there is insufficient evidence to determine the preferredmethod.The overall aim of this thesis was therefore to compare andevaluate the use of FA and RA for correcting anterior crossbitewith functional shift in the mixed dentition, with special referenceto clinical effectiveness, stability, cost-effectiveness and patientperceptions. Evidence-based, randomized controlled trial (RCT)methodology was used, in order to generate a high level of evidence.The thesis is based on the following studies:The material comprised 64 patients, consecutively recruited fromthe Department of Orthodontics, Faculty of Odontology, Malmö University, Sweden and from one Public Dental Health Service Clinicin Malmö, Skane County Council, Sweden. The patients were nosyndrome and no cleft patients. The following inclusion criteria wereapplied: early to late mixed dentition, anterior crossbite affecting oneor more incisors with functional shift, moderate space deficiency inthe maxilla, no inherent skeletal Class III discrepancy, ANB angle>0º, and no previous orthod