Efficacy of a four-curve auxiliary arch at preventing maxillary central incisor linguoclination during orthodontic treatment: A finite element analysis

Abstract

Abstract Background The correct torque of the incisors helps assess the effect of orthodontic treatment; however, evaluating it effectively remains a challenge. Improper anterior teeth torque angle can cause cortical bone fracture and root exposure. Methods A three-dimensional finite element model of the maxillary central incisor torque controlled by a self-made four-curvature auxiliary arch was established, And the experiments were divided to simulate four different group: (1) molar ligation group ; (2) micro-implant ligation group; (3) molar retraction group ༛(4) micro-implant retraction group༛and the retracted traction force was set at 1.15 N. The displacement of the maxillary dentition and periodontal ligament stress values were analyzed with different torque forces (0.5 N, 1 N, 1.5 N, 2 N) placed on the incisors. Results Provided the absence of a tooth extraction gap, when the four-curvature auxiliary arch was used in conjunction with absolute anchorage, the recommended force value was of < 1.5 N. when maxillary central incisor retraction, a force value of < 1 N was recommended. In the case of no-implant anchorage, whether there is tooth extraction gap or not, the recommended force value was of < 1 N. The stress on the other teeth did not exceed the value of that on the periodontal ligament. The effect of using the four-curvature on the incisors was significant. Conclusions The proposed approach may help improve treatment maxillary central incisor for poor torque and avoid cortical bone fracture and root exposure