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Study name	Evaluation of efficacy and efficiency of a removable esthetic appliance for solving teeth crowding in the childhood: a randomized clinical trial
Methods	2‐arm parallel RCT
Participants	Target: 40 participants, 20 in each group Inclusion criteria: 7 to 11 years old, mixed dentition phase, with definitive primary crowding of at least 3 mm Exclusion criteria: presence of agenesis of one or more upper incisors, need for the use of extraoral or extraction mechanics, presence of caries lesions, history of orthodontic treatment, cleft lip and palate, syndromes or any type of systemic or neurological alteration that makes it impossible to perform interventions and presence of white spot lesion or caries already established
Interventions	Invisible aligners versus fixed partial 4 x 2 mechanical appliances
Outcomes	"Primary outcome: primary anterior and superior crowding correction in the mixed dentition ‐ at least 2mm Little's index change. Secondary outcome: better white spot lesion prevention during the appliance use".
Starting date	21 August 2019
Contact information	Vinicius Augustus Merino da Silva, Faculdade de Odontologia de Bauru/FOB/USP, Brazil vinisilva@usp.br
Notes	Emailed author; awaiting contact

RCT: randomised controlled trial