Fig. 1
From: Mechanical force system of double key loop with finite element analysis
Configuration and dimensions of the double key loop (DKL): a Clinical use of DKL for closure of the upper premolar extraction space. b Dimension of the key loop, with a height of 6 mm and width of 4 mm. c Definition of forces and moments. Positive force indicated intrusion of teeth, and negative force indicated extrusion of teeth. Positive moments rotated the anterior tooth clockwise, and negative moments rotated the anterior tooth counterclockwise