闭口螺旋圈与 T 形曲关闭间隙的疗效比较：一项有限元研究。

Comparative assessment of the efficacy of closed helical loop and T-loop for space closure in lingual orthodontics-a finite element study.

机构信息

Department of Orthodontics and Dentofacial Orthopedics, Babu Banarasi Das College of Dental Sciences (BBDCODS), Lucknow, India.

出版信息

Prog Orthod. 2018 May 28;19(1):14. doi: 10.1186/s40510-018-0210-8.

BACKGROUND

Retraction in lingual orthodontics has biomechanical differences when compared to labial orthodontics, which is not yet established. Thus, we have intended to compare the biomechanical characteristics of closed helical loop and T-loop on 1 mm activation with 30° of compensatory curvatures during retraction in lingual orthodontics.

METHODS

STb lingual brackets were indirectly bonded to maxillary typhodont model that was scanned to obtain FEM model. Closed helical loop (2 × 7 mm) and T-loop (6 × 2 × 7 mm) of 0.016″ × 0.016″ TMA wire were modeled without preactivation bends. Preactivation bends at 30° were given in the software. Boundary conditions were set. The force (F) and moment (M) of both the loops were determined on 1 mm activation, using ANSYS software. M/F ratio was also calculated for both the loops.

RESULTS

T-loop exerted less force, thus increased M/F ratio as compared to closed helical loop on 1 mm activation.

CONCLUSIONS

When torque has to be preserved in the anterior segment during retraction in lingual orthodontics, T-loop can be preferred over closed helical loop.

背景

与唇侧正畸相比，舌侧正畸的矫正回缩在生物力学上存在差异，这一点尚未确定。因此，我们旨在比较在舌侧正畸中回缩时，1mm 激活下闭合螺旋圈和 T 型圈在 30°补偿曲线上的生物力学特征。

方法

STb 舌侧托槽间接粘结在上颌 Typhodont 模型上，扫描获得有限元模型。0.016″×0.016″TMA 丝的闭合螺旋圈（2×7mm）和 T 型圈（6×2×7mm）未进行预激活弯曲建模。在软件中给予 30°的预激活弯曲。设置边界条件。使用 ANSYS 软件确定两种环在 1mm 激活时的力（F）和力矩（M）。还计算了两种环的 M/F 比值。