Orthodontic Treatment in Adolescents With Crowding and Displaced Teeth

The purpose is to fill knowledge gaps identified for orthodontic treatment using a novel study design that has not been implemented in the dental field or in orthodontics. The study design comprises an analysis, where outcomes of two techniques are assessed at several efficacy levels by different methods. Moreover, the project is designed to include a longtime follow-up that is unique in orthodontic treatment. The aim is to compare two techniques with buccally fixed appliance in a multicenter RCT of adolescents aged 12 to 17 years with crowding and tooth displacement. In the intervention group, patients will be treated with a self-ligating bracket system, and in the control group with a conventional bracket system. Outcomes will be assessed from the clinical, patients' and economic perspectives as:Tooth alignment, function and adverse side effectsPatients' perception of pain, function and quality of lifeCost-effectiveness.

The eligibility criteria were set as follows:Age at treatment start: 12-17 yearsCrowding and displaced teethMaximum one cusp width deviation from normal sagittal relationOverbite ≥ 0 mmNormal or only dentoalveolar transversal discrepancyNo missing permanent teeth up to first molarsTreatment needed according to IOTN or ICON index and treated in accordance with the Swedish system of free child and youth dental careThe exclusion criteria were set as:Skeletal anomaliesRheumatoid arthritisPrevious orthodontic treatmentImpacted teethOngoing sucking habitsPrevious trauma to teeth or jaws with subjective, clinical, or radiographic signs: periapical pathology; probing depth ≥ 5 mm at ≥ 4 surfaces of central incisors or first molarsVisible plaque grade 3Treatment plan including extractions or other appliances than fixed buccal appliancesCommunication difficulties.