Online published on 28 May, 2014.
The aim of this study was to evaluate the effects of the removable functional appliance (Twin block) with varying construction bites on the mandible with 3-dimensional (3D) finite element stress analysis.
A 3D finite element model of the mandible was constructed from the CBCT generated images of a growing boy. The model simulated mandibular protraction, with 5 mm and 8 mm of sagittal advancement and 3 mm of vertical opening. The changes were studied with the finite element method, in the form of displacement, Maximum Von Mises stress and Maximum Principal stress regions.
In the resting stage, maximum displacement was from canine to canine while in the construction bite 1 and 2, it was in the premolar region. Maximum von Mises stress and maximum principal stress changes were more in the 8 mm horizontal advancement. The regions near the muscle attachment areas were affected the most.
Functional appliances can cause morphologic changes on the mandible by activating the masticatory muscles to change the growth direction.
