Department of Stomatology, Fujian Medical University Union Hospital, No. 29 of Xinquan Street, Gulou District, Fuzhou, 350001, China.
BMC Oral Health. 2021 Oct 6;21(1):501. doi: 10.1186/s12903-021-01859-8.
The application of intermaxillary traction is often accompanied by the unexpected movement of dentition, especially anchorage teeth. The aim of this study was to comprehensively compare the influence of cross-sectional shape of ribbon arch wires with edgewise and round wires on intermaxillary traction in Class II malocclusion treatment using FEA simulation.
The dentofacial structure was simulated in finite element software. A retraction force of 1.5 N was applied to different cross-sectional orthodontic arch wires: a ribbon wire (0.025 × 0.017-in. and 0.025 × 0.019-in.), a rectangular wire (0.017 × 0.025-in. and 0.019 × 0.025-in.) and a round wire (Φ 0.018-in. and Φ 0.020-in.).
Among the three groups, ribbon wire (0.025 × 0.017-in. and 0.025 × 0.019-in.) exhibited the lowest displacement in the X-axis (12.61 μm and 12.77 μm, respectively) and Z-axis (8.99 μm and 9.06 μm, respectively). However, the 0.025 × 0.017-in. ribbon wire showed the highest Y-axis displacement. In the round wire group, Φ 0.020-in. wire displayed less rotation than Φ 0.018-in. wire, where the sagittal, frontal and occlusal rotation of Φ 0.020-in. wire was almost half of that of Φ 0.018-in. wire. The movement of the first molar region was intermediate between the ribbon arch group and the round wire group. Notably, the values of the 0.025 × 0.017-in. arch wire displacement, which were higher than those of any other group, peaked at 0.019 mm in the central incisor region with a spike-like shape. The deformation range of the Φ 0.018-in. wire group was the largest in this study.
The cross-section of the arch wire influenced force delivery in Class II intermaxillary traction. With the same shape, a larger cross-sectional area led to less mandibular dentition movement. For the rectangular arch wire and ribbon arch wire groups, since the height and width were inverted, the vertical displacement of anchorage teeth in the ribbon wire group was reduced, but the possibility of buccal tipping in mandibular anterior teeth also increased.
颌间牵引的应用常伴随着牙齿的意外移动，尤其是支抗牙。本研究旨在通过有限元模拟，全面比较方丝弓和圆丝弓不同弓丝的截面形状对安氏Ⅱ类错[牙合]患者颌间牵引的影响。
在有限元软件中模拟牙颌面结构。在不同的正畸弓丝上施加 1.5 N 的回弹力：方丝弓（0.025×0.017 英寸和 0.025×0.019 英寸）、矩形丝（0.017×0.025 英寸和 0.019×0.025 英寸）和圆丝（0.018 英寸和 0.020 英寸）。
在三组中，方丝弓（0.025×0.017 英寸和 0.025×0.019 英寸）在 X 轴（分别为 12.61μm 和 12.77μm）和 Z 轴（分别为 8.99μm 和 9.06μm）的位移最小。然而，0.025×0.017 英寸的方丝弓在 Y 轴上的位移最大。在圆丝组中，与 0.018 英寸的圆丝相比，0.020 英寸的圆丝旋转度更小，其中 0.020 英寸的圆丝矢状、额状和牙合面旋转度几乎是 0.018 英寸的一半。第一磨牙区的运动介于方丝弓组和圆丝弓组之间。值得注意的是，0.025×0.017 英寸弓丝的位移值高于其他任何组，在中切牙区域以峰值 0.019mm 的形式呈尖峰状。在本研究中，0.018 英寸圆丝组的变形范围最大。
弓丝的截面形状影响安氏Ⅱ类颌间牵引的力传递。在相同形状下，较大的横截面积导致下颌牙列运动减少。对于方丝弓和方丝弓组，由于高度和宽度颠倒，方丝弓组的支抗牙垂直位移减少，但下颌前牙颊向倾斜的可能性也增加。
