TO EVALUATE THE VARIABILITY OF TORQUE VALUES OF DIFFERENT COMMERCIALLY AVAILABLE BRACKET SYSTEMS

Torque is the most misunderstood term in orthodontics, it is defined as the change in bucco-lingual inclination of the tooth. It is expressed when a rectangular wire twists in the bracket slot causing torsion.The magnitude of this change is dependent on a number of factors such as size of the bracket, size of the archwire, torque built-in the bracket, play between the archwire and bracket slot, magnitude of the twist. Deviation from the values claimed by the manufacturers in either slot dimension, dimension of wire, built-in torque of bracket slot can seriously affect the treatment outcome. This study was performed to compare the torque that is built in the base of the bracket slot with the values claimed by the manufacturers. 180 Maxillary right central incisor brackets from 10 different manufacturers were studied. The brackets were of the M.B.T prescription with a dimension of 0.022x0.028 inch and claimed torque value of +17 degrees. Astereomicroscope was used to accurately evaluate the torque angle values of the brackets. The study concluded that most of the manufacturing companies show deviation from the claimed nominal torque value of +17 degrees. One should exercise caution while selecting the bracket system as most of the brackets show deviation from ideal values.