Lever arms and sliding mechanics - A biomechanical approach for torque control in lingual orthodontics: Case series

• Published in: Journal of Indian Orthodontic Society Vol. 50; no. 5; pp. 68 - 75
• Main Authors: Aravind, M, Belludi, Anup, Vishal, Sarda
• Format: Journal Article
• Language: English
• Published: Wolters Kluwer India Pvt. Ltd 01.12.2016; Medknow Publications and Media Pvt. Ltd
• Subjects: Orthodontics; Center of resistance; torque control; lever arm
• ISSN: 0301-5742; 0974-9098

Ever since the introduction of fixed appliance, a constant search is in progress to develop an appliance which can effectively control the anterior teeth during orthodontic treatment. As it is difficult to meet the requisites of all cases with a standard appliance, several biomechanical principles are being thought of, to overcome the difficulties. Controlling the torque is one of the toughest challenges a clinician faces during lingual sliding mechanics. The challenge posed may be attributed to the moment generated in the maxillary anterior teeth during lingual retraction, considering the biomechanical correlation between the center of resistance of maxillary anterior teeth and the resultant retraction force vector in lingual orthodontics. There are several ways to counteract the torque loss and at the same time effectively retract the maxillary anterior teeth. This can be achieved either by customizing the lingual bracket base or biomechanically by optimizing the retraction force vector. This article is an effort to emphasize the role of lever arms in optimizing retraction mechanics and torque control in lingual sliding mechanics.