Biomechanical analysis for total distalization of the mandibular dentition: A finite element study.

INTRODUCTION: The aim of this finite element study was to analyze and clarify the mechanics of tooth movement patterns for total distalization of the mandibular dentition based on force angulation.

METHODS: Long-term orthodontic movement of the mandibular dentition was simulated by accumulating the initial displacement of teeth produced by elastic deformation of the periodontal ligament.

RESULTS: Displacement of each tooth was caused by movement of the whole dentition, elastic deflection of the archwire, and clearance gap between the archwire and bracket slot. The whole dentition was rotated clockwise or counterclockwise when the line of action of the force passed below or above the center of resistance. Elastic deflection of the archwire induced a lingual tipping of the anterior teeth. It became larger when increasing the magnitude of angulation. The archwire could be rotated within the clearance gap between the archwire and the bracket slot, and thereby the teeth tipped.

CONCLUSIONS: Mechanics of total mandibular distalization was clarified. Selective use of force angulation with a careful biomechanical understanding can achieve proper distalization of the whole mandibular dentition.