Anterior vertical control using temporary anchorage devices in bimaxillary protrusion treatment

Abstract

Abstract Background: Temporary anchorage devices (TADs) are used for retraction of the anterior teeth in cases of severe bimaxillary protrusion. There have been a number of studies regarding anterior tooth movement using TADs performed by simulation systems and actual treated materials with sliding mechanics. However, there are few studies regarding anterior tooth movement using TADs treated by loop mechanics The purpose of this study was to investigate the effect of TADs in anterior tooth movement using loop mechanics performed actual cases of bimaxillary protrusion. Methods: This study was performed in 20 adult patients with severe bimaxillary protrusion treated with four bicuspid extraction with sliding or loop mechanics using TADs. The skeletal and denture patterns, as well as the soft tissue profile from pre-treatment (T0) and post-treatment (T1) lateral cephalograms, were compared between sliding and closing loop mechanics. Results: The use of TADs is useful to retraction of anterior teeth without molar anchorage loss. in sliding and loop mechanics. The upper anterior teeth were less tipped and lower anterior teeth were more upright resulting in less clockwise rotation of the occlusal plane in loop mechanics compared sliding mechanics. Conclusion: Towing the upper anterior teeth at the same height from TADs prevents clockwise rotation of the occlusal plane in loop mechanics, likely because of effective intrusion and lingual root tipping of the upper anterior teeth by pulling the closing loop from the TADs for activation.