Biomechanical implications of rotation correction in orthodontics: Case series

According to Bacetti (1998) tooth rotation is defined as observable mesiolingual or distolingual intra-alveolar displacement of the tooth around its longitudinal axis.1 Tooth rotations cause difficulty in finishing fixed orthodontic treatment. In Begg's technique rotation springs are used to correct tooth rotations. These springs are engaged into the vertical slot of the bracket. In case of preadjusted edgewise technique and edgewise technique brackets doesn't have a vertical slot. So alternative methods are used to correct tooth rotations.2 Various methods include engaging NiTi arch wire into the bracket slot, off centering the bracket, using rotation wedges, creating a couple on the rotated tooth, by using ligature ties.3 The purpose of this case series is to discuss the biomechanics involved in rotation correction using bracket offsetting and couple.