Participants
agenesis
SYNDROMES
Initially, we invited patients with ongoing orthodontic treatment at the Orthodontic Clinic Växjö, Public Dental Service, Region Kronoberg, Sweden, to participate in the study. The inclusion criteria were adolescents treated with a fixed appliance in the maxilla or the maxilla and mandible. The exclusion criteria were patients with clefts or syndromes, patients with agenesis or extracted maxillary anterior teeth, patients treated with removable appliances and patients who underwent orthognathic surgery. Enrolment commenced in October 2013 and ended in October 2017. The patients were followed during a 2-year retention period, and retention devices were removed until October 2019. The patients were then further followed for a 1-year post-retention period until December 2020, when the stability of the maxillary anterior teeth was reassessed. The study was approved by the Regional Ethical Research Board, Linköping, which follows the Declaration of Helsinki (Dnr. 2013/131) and registered in Clinical Trials.gov (NCT04616755).