目的:通过有限元分析(FEA)评估有和没有颊根扭矩的不同附件配置对使用矫正器实现的扩张运动的影响。
方法:对上颌磨牙施加0.25mm颊扩张力以不同的附着结构进行FEA建模:测试了八个模型(1)无附着(NA),(2)水平附件(HA),(3)牙龈斜切水平附件(GHA),和(4)八角倾斜水平附件(OHA),以及具有6obucleal根部扭矩的型号,(5)无附件(TNA),(6)水平附件(THA),(7)牙龈斜切水平附件(TGHA),和(8)八角倾斜水平附件(TOHA)。
结果:在所有模型中,第一磨牙和第二磨牙均表现出颊倾斜。在NA中观察到磨牙的颊倾翻量最高(6CMB,0.232mm;6CMP,0.246mm;7CMB,0.281mm;7CMP,0.312毫米)和GHA(6CMB,0.230;6CMP,0.245;7CMB,0.279mm;7CMP,0.311mm)型号,分别,虽然在TOHA模型中观察到最小的倾翻(6CMB,0.155mm;6CMP,0.168毫米;7CMB,0.216mm;7CMP,0.240毫米)。在所有组中,第二磨牙的颊倾翻高于第一磨牙。
结论:这项FEA研究表明,使用矫正器尖端的上颌磨牙颊部扩张以及使用对角斜面的附件和添加颊根扭矩可减少不受控制的颊倾翻。
OBJECTIVE: 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).
METHODS: 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 6obuccal root torque, (5) no attachment (TNA), (6) horizontal attachment (THA), (7) gingivally beveled horizontal attachment (TGHA), and (8) occlusally beveled horizontal attachment (TOHA).
RESULTS: 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.
CONCLUSIONS: 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.