Shape of dental arches after self-ligating appliance in adolescents: A 30-week prospective study.

Abstract Objective To analyze the variability of dental arches shape before and after alignment with a passive bimaxillar Damon® self-ligating fixed appliance in adolescents. Material and methods 55 patients aged 13 years, with definitive denture, were enrolled. The dental arch was assessed before (T1) and after a 30-week dental alignment period (T2). The archwire was changed every 6 weeks at each orthodontic appointment, following the Damon® protocol. In addition to the linear measurement, the Superimposition Penin Analysis (SPA) based on Procrustes method was used to superimpose and discriminate dental arches shape. Results Transverse and sagittal dental arch distances taken on casts significantly increased from T1 to T2. The dental arches superimpositions revealed a significant decrease of the shape variability from T1 to T2. There was a great variability of dental arch shapes at T1, probably dependent from the morphologic type and then the muscular environment or an eventual osteopathic disease. This study highlighted that the mean dental arch shape at the end of treatment was close to a parabola: rounded at the front, narrow at the back with an expansion of the premolar area. Conclusion Contrary to the theoretical concept of the self-ligating fixed appliances, dental arches evidenced uniformity at T2. The results did not indicate any individual development of the dental arch shape.