Efficacy Comparison Of Clear Aligner And Forsus Appliance In The Treatment Of Adolescent Patients With Mandibular Retraction

Objective: In this study,we selected the appropriate age of adolescent patients with mandibular retrusion according to Baccetti ’ s modified vertebral staging method,and treated them with clear aligner MA and Forsus appliance respectively.Through the comparison of lateral cephalograms before and after treatment,the changes of soft and hard tissues after-treatment of the two kinds of appliances were analyzed,the difference of curative effect between the two was evaluated and the mechanism of appliance was discussed,to provide the corresponding reference for clinical treatment selection.Methods: In this study,22 patients with Angle ’s Class II mandibular retraction treated in Hefei Stomatological Hospital from January 2018 to October 2020 were selected.They were all in the early or peak stage of growth,including 8 females and 14 males,with an average age of 11.8 years old.The cephalometric radiographs were taken before the treatment,12 patients were treated with Forsus appliance,and 10 patients were treated with the clear aligner MA.After the treatment,the cephalometric radiographs were taken again,and the cephalometric radiographs taken twice were measured,and then the measurement results were statistically analyzed.Reaults: The treatment was completed in both groups,and the SNB and ANB angles were significantly decreased in the Forsus appliance group and the clear aligner MA group(P < 0.05).The B-Y axis,Pg-Y axis,and the length of mandible increased significantly(P < 0.05),confirming the growth of mandible.U1-NA and L1-NB increased significantly(P < 0.05);L1-MP and L1-Y axis increased significantly(P< 0.05);U1-SN decreased significantly(P < 0.05);Both OB and OJ decreased significantly(P < 0.05);SNA angle and Co-Y axis increased,but there was no statistical significance,and there was no statistical significance before and after MP-SN and A-Y axis correction.The comparison between the two groups showed that only the four items of U1-Y axis,L1-NB,U1-SN,and L1-MP were statistically significant(P < 0.05).In terms of soft tissue changes,the nasal lip angle and Z angle of the two groups were significantly increased(P < 0.05).UL-Eline,LL-Eline,upper and lower lip chin angle,and H angle decreased significantly(P < 0.05);There was no significant difference in the comparison between the two groups.Conclusion: Both clear aligner MA and Forsus appliance can improve the jaw,teeth,and soft tissue of patients with mandibular retraction.Neither of the two appliances showed a positive effect on the growth inhibition of the maxilla.Both of them played a promoting role in the growth of the mandible,and there was a significant increase after treatment.Compared with Forsus appliance,clear aligner MA has more advantages in controlling the labial inclination of lower anterior teeth,but Forsus appliance may be a better choice for patients with higher mandibular plane angle.After the treatment of the two appliances,the changes of the facial profile of the two groups of patients with mandibular retraction remained consistent,and were improved.