Cho Keun-Chul, Yang Il-Hyung, Lee Michael, Kim Ki Beom, Baek Seung-Hak
Department of Orthodontics, School of Dentistry, Seoul National University, Seoul, Korea.
Department of Orthodontics, Saint Louis University, Saint Louis, MO, USA.
Korean J Orthod. 2025 Jul 25;55(4):290-305. doi: 10.4041/kjod25.003. Epub 2025 Apr 29.
To investigate the pattern of change in force and moment according to the amounts of labial tipping and the material types of clear aligners (CA).
A 3D-printed maxillary typodont system, including crown, root, and periodontal ligament space, was constructed. Six groups were established based on the amount of labial tipping of #12 (0.3 mm and 0.6 mm), and the material types (Zendura [thermoplastic, one-layer, 0.75 mm], Trioclear [thermoplastic, three-layer, 0.5 mm], and Graphy TA-28 [direct printing, 0.5 mm]) (n = 6/group). A six-axis mechanical sensor apparatus was connected to the roots. Force and moment were measured after seating the CA in a 37°C water bath.
When comparing 0.3 mm and 0.6 mm tipping, #12 showed an increase in labial inclination moment (Lab-inclination moment) in Zendura ( < 0.05); a decrease in labial force and an increase in Lab-inclination-moment in Trioclear ( < 0.05, P < 0.01); while a lingual force and Lab-inclination moment without significant change in Graphy (all > 0.05). For 0.3 mm tipping, the amounts of labio-lingual forces and Lab-inclination moment did not differ among the three materials (all > 0.05). However, at 0.6 mm tipping, Zendura exerted a greater labial force than Trioclear, while Graphy produced a lingual force ( < 0.01). Zendura and Trioclear generated a stronger Lab-inclination moment compared to Graphy ( < 0.01). Despite displaying unexpected force and moment directions, Graphy consistently exhibited the lowest absolute values among the groups.
Clinicians should select the appropriate aligner material based on the specific biomechanical requirements to prevent unexpected forces and moments.
根据唇倾程度和透明矫治器（CA）的材料类型，研究力和力矩的变化模式。
构建一个3D打印的上颌模型系统，包括牙冠、牙根和牙周膜间隙。根据12号牙的唇倾程度（0.3mm和0.6mm）和材料类型（Zendura[热塑性，单层，0.75mm]、Trioclear[热塑性，三层，0.5mm]和Graphy TA-28[直接打印，0.5mm]）分为六组（每组n = 6）。将一个六轴机械传感器装置连接到牙根上。在37°C水浴中佩戴CA后测量力和力矩。
比较0.3mm和0.6mm唇倾时，12号牙在Zendura中唇倾力矩增加（<0.05）；在Trioclear中唇向力减小，唇倾力矩增加（<0.05，P<0.01）；而在Graphy中舌向力和唇倾力矩无显著变化（均>0.05）。对于0.3mm唇倾，三种材料的唇舌向力和唇倾力矩大小无差异（均>0.05）。然而，在0.6mm唇倾时，Zendura产生的唇向力大于Trioclear，而Graphy产生舌向力（<0.01）。与Graphy相比，Zendura和Trioclear产生更强的唇倾力矩（<0.01）。尽管Graphy显示出意外的力和力矩方向，但在各组中其绝对值始终最低。
临床医生应根据特定的生物力学要求选择合适的矫治器材料，以防止出现意外的力和力矩。
