Faculty of Dentistry, Department of Orthodontics, Karadeniz Technical University, Trabzon, Turkey.
Faculty of Dentistry, Department of Orthodontics, Hacettepe University, Ankara, Turkey.
BMC Oral Health. 2024 Aug 9;24(1):921. doi: 10.1186/s12903-024-04544-8.
To evaluate the effects of different attachment configurations with and without buccal root torque on expansion movements achieved with aligners through finite element analysis (FEA).
FEA modelling was done with 0.25 mm buccal expansion force application to the maxillary molars with different attachment configurations: Eight models were tested (1) no attachment (NA), (2) horizontal attachment (HA), (3) gingivally beveled horizontal attachment (GHA), and (4) occlusally beveled horizontal attachment (OHA), as well as models with 6buccal root torque, (5) no attachment (TNA), (6) horizontal attachment (THA), (7) gingivally beveled horizontal attachment (TGHA), and (8) occlusally beveled horizontal attachment (TOHA).
The first and second molars exhibited buccal tipping in all models. The highest amount of buccal tipping for the molars was observed in the NA (6CMB, 0.232 mm; 6CMP, 0.246 mm; 7CMB, 0.281 mm; 7CMP, 0.312 mm) and GHA (6CMB, 0.230; 6CMP, 0.245; 7CMB, 0.279 mm; 7CMP, 0.311 mm) models, respectively, while the least tipping was observed in the TOHA model (6CMB, 0.155 mm; 6CMP, 0.168 mm; 7CMB, 0.216 mm; 7CMP, 0.240 mm). In all groups, the buccal tipping of the second molars was higher than that of the first molars.
This FEA study showed that expansion with aligners tip maxillary molars buccally and the use of occlusally beveled attachments and addition of buccal root torque reduces uncontrolled buccal tipping.
通过有限元分析（FEA）评估带有和不带有颊向根转矩的不同附着体配置对上颌牙齿扩展运动的影响。
在 0.25mm 颊向扩展力施加于上颌磨牙的情况下，通过 FEA 建模，对不同的附着体配置进行测试：（1）无附着体（NA）、（2）水平附着体（HA）、（3）龈向斜切水平附着体（GHA）和（4）牙合向斜切水平附着体（OHA），以及带有 6 度颊向根转矩的模型：（5）无附着体（TNA）、（6）水平附着体（THA）、（7）龈向斜切水平附着体（TGHA）和（8）牙合向斜切水平附着体（TOHA）。
所有模型中的第一和第二磨牙都出现颊向倾斜。在 NA（6CMB，0.232mm；6CMP，0.246mm；7CMB，0.281mm；7CMP，0.312mm）和 GHA（6CMB，0.230mm；6CMP，0.245mm；7CMB，0.279mm；7CMP，0.311mm）模型中，磨牙的颊向倾斜量最大，而在 TOHA 模型中（6CMB，0.155mm；6CMP，0.168mm；7CMB，0.216mm；7CMP，0.240mm）观察到的倾斜量最小。在所有组中，第二磨牙的颊向倾斜量均高于第一磨牙。
本 FEA 研究表明，使用直丝弓矫治器扩弓会使上颌磨牙颊向倾斜，使用牙合向斜切附着体和颊向根转矩可以减少不受控制的颊向倾斜。
