Mechanism of lingual tipping of anterior teeth with sliding mechanics in lingual orthodontics

Finite element method

Abstract

In lingual movement of anterior teeth with sliding mechanics, the mechanism of lingual tipping occurring in the anterior teeth was investigated based on the finite element method. In the intramaxillary retraction, lingual tipping of the anterior teeth was caused by elastic deflection of the archwire. When decreasing the retraction force or increasing the archwire size, the lingual tipping decreased. When using an archwire with antibowing bend, deflection of the archwire and lingual tipping of the anterior teeth could be prevented. When incorporating lingual root torque into the anterior brackets, the lingual tipping of the anterior teeth could be prevented, but the deflection of the archwire could not be prevented. In a retraction of the anterior teeth using anchor screw, lingual tipping was caused by not only deflection of the archwire but also rotation of the whole dentition. When incorporating antibowing bend into the archwire, the deflection of the archwire could be prevented, but the rotation of the whole dentition could not be prevented. When applying a parallel force to the archwire with a long arm, the action line of the retraction force passed near the center of resistance of the anterior teeth, and thereby the anterior teeth moved bodily without rotation of the whole dentition and deflection of the archwire.