Effect of the depth and angle of the reverse-curve arch wires on the perpendicular force exerted to teeth / 实用口腔医学杂志

ABSTRACT

Objective:To analyze the perpendicular force on each tooth produced by the reverse-curve arch wires of various angles and depths using the method of 3-D finite element (3-D FEM) analysis. Methods:3-D FEM models of lower teeth, periodontal ligaments and alveolar bone as well as the 0.46 mm?0.64 mm inch stainless steel reverse-curve arch wires with different angles and depths were developed with the ANSYS finite element software, and the displacements of deformation of the reverse-curve arch wires were established on the models. Results:A ideal 3-D FEM was construct,including 2 709 elements and 1 969 nodes. The depth and angle of the reverse-curve arch wires produced obvious effect on the force exerted to teeth, and they could alter both the strength and the direction of the force. The force was mainly loaded on the canines, the second premolars and the molars, while less loaded on the incisors. Affected by the reverse-curve arch wires, the perpendicular force on the incisors were brought intrusively and on the molars were brought intrusively and distal upright; however, the canines and the bicuspids, in the perpendicular direction, moved along with the transformation of the angle and depth of the reverse-curve arch wires. When the angle of reverse-curve arch wires was fixed, the intrusive force on the incisors and molars was increased along with the increase of depth of the reverse-curve arch wires. Perpendicularly, the canines underwent a process from extrusion to intrusion, while the bicuspids were from intrusion to extrusion. When the depth of reverse-curve arch wires was fixed, the intrusive force on the incisors and molars was increased along with the increase of angle of the reverse-curve arch wires. The canines underwent a process from intrusion to extrusion.Conclusion:The variation of the angle and depth of the reverse-curve arch wires may produce evident effect on the force exerted to teeth.