Treatment Outcome of Lingual Appliance with Anterior Vertical Slots in Bialveolar Protrusion Patients
Seong-Jin Ahn1 , Seung-Wook Oh2
1 Department of Orthodontics, School of Dentistry, Kyung Hee University, Seoul
2 Department of Orthodontics, Kyung Hee Dental Hospital, Seoul, Korea
Purpose: The objective of study was to assess the effectiveness of anterior torque control in premolar extraction cases using customized ribbon-wise lingual appliances and pre-torque archwire.
Materials & Methods: A total of 20 samples included patients who were treated with the extraction of four first premolars using lingual appliances. The samples were divided into two groups; lingual bracket with anterior vertical slot group (LVS, n=10) and lingual bracket with anterior horizontal slot group (LHS, n=10). The initial and final cephalometric radiographs were measured. To assess changes between pre-treatment and post-treatment within LVS group, a Wilcoxon signed rank test was undertaken and to compare the changes between two groups, Mann Whitney U test was used.
Results: The amount of retraction was gained (–5.71±1.70 mm) with torque changes of –10.30±3.10° in LVS group and the amount of retraction was gained (–7.25±3.23 mm) with torque changes of –13.00±8.51° in LHS group.
Conclusion: Pre-torqueing archwire with customized anterior vertical slot lingual brackets showed comparable anterior torque control to conventional horizontal lingual brackets with lever-arms and mini-screws. However, it was difficult to control the horizontal anchorage loss.
Key words: Lingual orthodontic treatment, Premolar extraction, Anterior vertical slots, Anterior horizontal slot, Anterior torque control
Korean J Lingual Orthod 2019;8(1):10-18