From: Biomechanical effects of different staging and attachment designs in maxillary molar distalization with clear aligner: a finite element study
The von Mises stress of root (MPa)
11
12
13
14
15
Without attachment
0.268
0.627
0.316
0.248
0.449
With horizontal attachment
0.198
0.469
0.216
0.181
0.358
With vertical attachment
0.199
0.468
0.213
0.179
0.356