Nandan Hemwati, Kumar Ch Sudheer, Jha Pragjyoti
Cleft and Craniofacial Orthodontics, GSR Institute of Craniofacial Surgery, Hyderabad, IND.
Department of Dentistry, Government Medical College, Siddipet, IND.
Cureus. 2023 Feb 22;15(2):e35288. doi: 10.7759/cureus.35288. eCollection 2023 Feb.
Introduction This study was designed to explore the differences between two frictionless mechanics for canine retraction i.e., dual force cuspid retractor and T-loop segmental arch. T-loop for canine retraction creates a biomechanical system to deliver a predetermined force and a relatively constant moment-to-force ratio whereas dual force cuspid retractor uses power arms on buccal as well as palatal aspects for canine retraction. Bodily tooth movement can be achieved by both methods, but in this study, our main focus was to reduce the canine retraction timing with better three-dimensional control. Method This split-mouth study was conducted on a total of 20 cuspids of ten patients (five male and five female). Where one side of the arch was selected for T-loop and the other side for dual force cuspid retractor, randomly. Inclusion criteria for this study were; no congenitally missing teeth (excluding third molar), class I or class II molar relationship, no previous history of orthodontic treatment, good oral periodontal status, patients in whom extraction of maxillary first premolar during treatment was indicated. Both groups were compared for the duration of canine retraction, anchorage loss; tipping, and rotation of cuspid and molar, individually, after retraction. Result The result of this study showed that the duration of canine retraction was significantly less in group one, i.e., dual force cuspid retractor 73.8 ± 12.38 days, than in group two, i.e., T-loop 109.4 ± 16.71 days. The anchorage loss in group one was 0.60 ± 0.61 mm and that in group two was 2.40 ± 0.87 mm. Also, the amount of tipping and rotation of the cuspid and molar individually was significantly lesser in group one than in group two. Conclusion In this study, the dual force cuspid retractor shortens the duration of canine retraction with better three-dimensional control and better anchorage preservation when compared to T-loop.
引言 本研究旨在探讨两种用于犬牙后移的无摩擦力学方法之间的差异，即双力尖牙牵开器和T形曲片段弓。用于犬牙后移的T形曲创建了一个生物力学系统，以传递预定的力和相对恒定的力矩与力的比值，而双力尖牙牵开器在颊侧和腭侧使用力臂来实现犬牙后移。两种方法均可实现牙齿的整体移动，但在本研究中，我们的主要重点是在更好地进行三维控制的情况下缩短犬牙后移的时间。方法 本双盲研究共对10例患者（5例男性和5例女性）的20颗尖牙进行。随机选择牙弓的一侧使用T形曲，另一侧使用双力尖牙牵开器。本研究的纳入标准为：无先天性缺失牙（第三磨牙除外），I类或II类磨牙关系，无前正畸治疗史，良好的口腔牙周状况，治疗期间需拔除上颌第一前磨牙的患者。分别比较两组在犬牙后移持续时间、支抗丧失、尖牙和磨牙的倾斜及旋转情况。结果 本研究结果显示，第一组即双力尖牙牵开器组的犬牙后移持续时间明显短于第二组即T形曲组，分别为73.8±12.38天和109.4±16.71天。第一组的支抗丧失为0.60±0.61mm，第二组为2.40±0.87mm。此外，第一组中尖牙和磨牙各自的倾斜和旋转量明显小于第二组。结论 在本研究中，与T形曲相比，双力尖牙牵开器在更好地进行三维控制和更好地保留支抗的情况下缩短了犬牙后移的持续时间。
