[Clinical efficacy of clear aligners in treating bimaxillary protrusion].

Objective: To evaluate the efficiency of clear aligners in treating bimaxillary protrusion patients with first premolar extractions. Methods: Eleven patients with bimaxillary protrusion were selected in this study. All of them were treated by using clear aligners with four first premolar extractions and need maximal anchorage. Cephalometric analysis was carried out before and after treatment. Results: Cephalometric analysis results showed that significant changes in teeth and profile could be detected after clear aligner treatment and no change could be found in skeletal pattern. Upper and lower anterior teeth were retracted. The control of anterior torque and posterior anchorage were effective. The soft tissue analysis showed that position of upper and lower lip was significantly changed which improve the profile of patients. After treatment, the distance of U1 to NA and L1 to NB reduced by (5.19±4.12) mm and (4.53±1.20) mm, respectively. The differences were statistically significant ( P <0.01). Conclusions: Bimaxillary protrusion patients who needed premolar extractions and maximal anchorage could be treated with clear aligners.