Upper arch expansion and spontaneous upper first molar distorotation with Ni-Ti leaf springs and rapid maxillary expander compared to clear aligners : A randomized controlled trial. - Ugolini A; Bruni A; Abate A; Maspero C; Silvestrini-Biavati F; Lanteri V (Journal of orofacial orthopedics = Fortschritte der Kieferorthopadie : Organ/official journal Deutsche Gesellschaft fur Kieferorthopadie, 2026)