When the distance of the interincisor opening reached 13.3 mm, the central incisor was loaded at 3 kgf, which was greater than that for other teeth in the TheraBite^® appliance.
On the other hand, as the distance of interincisor opening was gradually increased, the canine and the first and second premolars were loaded gradually in the shell-shaped mouth opening appliance.
In addition, the central and lateral incisors were loaded at all times in the shell-shaped mouth opening appliance.