Flared incisors and deep overbite are challenging to treat orthodontic
ally. This paper describes the use of a three-piece base arch and Clas
s I elastics to correct deep overbite while simultaneously closing spa
ces. An analysis of the biomechanics and a discussion of the appliance
design are presented to help understand how the incisor axial inclina
tion can be corrected and controlled during orthodontic therapy. A cli
nical example illustrates the treatment sequence.