Sultanoğlu Erkan, Gürel Hakan Gürcan, Gülyurt Muzaffer
Orthodontics and Dentofacial Orthopedics, Biruni University, Istanbul, TUR.
Cureus. 2024 Aug 6;16(8):e66273. doi: 10.7759/cureus.66273. eCollection 2024 Aug.
Aim Rotation of the mandibular premolars during aligner treatment is a difficult movement to achieve accurately. The purpose of this study is to compare the effects of different attachment types and positions used in clear aligner treatments on the rotation movement and retention of clear aligners in the rotated first premolar teeth. The study also addressed the stress values in periodontal ligaments (PDLs) with finite element analysis. Materials and methods For purposes of this research, we created a mandibular tooth model and modeled the premolar tooth with a 30° rotation. Twelve separate groups were created by attaching horizontal rectangular, vertical rectangular, ellipsoid, and semi-ellipsoid attachments to the premolar tooth in buccal, lingual, and combined buccal and lingual ways. A model without attachments was created to be used as the control group. An activation movement of 0.25 mm was applied to the first premolar tooth in all 12 models. The study evaluated clear aligner displacement, von Misses stress on the PDL, and tooth displacements using the finite element stress analysis method. Results It was found that the group with horizontal rectangular attachments placed on both the buccal and lingual sides had the highest stress value in the PDL (0.1971 MPa) and the highest displacement in the tooth (0.1267 mm). Conversely, the group with semi-ellipsoid attachments placed both buccally and lingually had the least displacement movement in clear aligners (0.1441 mm). Conclusion The results indicate that groups with attachments provided better retention than groups without attachments. Models with horizontal, rectangular attachments showed significantly more tooth displacement compared to other models. Horizontal rectangular attachments placed buccally and lingually combined to provide tooth movement in rotated mandibular first premolars can be recommended for clinical use.
目的 在矫治器治疗过程中，下颌前磨牙的旋转是一项难以精确实现的移动。本研究的目的是比较在透明矫治器治疗中使用的不同附件类型和位置对旋转的第一前磨牙的旋转移动和透明矫治器固位的影响。本研究还通过有限元分析探讨了牙周膜（PDL）中的应力值。材料与方法 为了本研究的目的，我们创建了一个下颌牙齿模型，并对前磨牙进行建模使其有30°的旋转。通过将水平矩形、垂直矩形、椭圆形和半椭圆形附件以颊侧、舌侧以及颊侧和舌侧联合的方式附着在前磨牙上，创建了12个独立的组。创建一个没有附件的模型作为对照组。对所有12个模型中的第一前磨牙施加0.25 mm的激活移动。本研究使用有限元应力分析方法评估透明矫治器的位移、PDL上的冯·米塞斯应力以及牙齿位移。结果 发现颊侧和舌侧均放置水平矩形附件的组在PDL中的应力值最高（0.1971 MPa），牙齿的位移也最大（0.1267 mm）。相反，颊侧和舌侧均放置半椭圆形附件的组在透明矫治器中的位移移动最小（0.1441 mm）。结论 结果表明，有附件的组比没有附件的组具有更好的固位。与其他模型相比，带有水平矩形附件的模型显示出明显更多的牙齿位移。对于旋转的下颌第一前磨牙，推荐在颊侧和舌侧联合放置水平矩形附件以实现牙齿移动，可用于临床。
