The effect of different thickness of power ridge on torque control during anterior retraction using clear aligners in patients with periodontal disease: a finite element analysis

In patients with periodontal disease, the displacement of the entire maxillary dentition increased in comparison to those with normal alveolar bone. And an appropriate thickness of power ridge is beneficial to achieve torque control of anterior teeth. However, excessive thickness of power ridges is not suitable for anterior tooth retraction because of the stress concentration on the PDL.