Influence of tooth morphology on torque expression with preadjusted edgewise appliance in anterior teeth in a mixed indian population: An in-vitro study

The effect of racial and ethnic variations of dental morphological traits on torque expression of preadjusted edgewise appliances has rarely been documented. This in vitro experiment was carried out with the aim to study the extent to which the anterior tooth morphology of a mixed Indian population affects torque expression of a preadjusted edgewise appliance. This study was conducted on extracted maxillary and mandibular anterior teeth of a mixed Indian population. These teeth were divided into two similar groups and were bonded with 0.018” Roth and MBT prescriptions. Full slot engagement was obtained using a 0.018” x 0.025” stainless steel wire to study how the variation in the tooth morphology affects the torque expression. Each tooth with the test wire engaged in the slot was radiographed using standardised procedures. The radiographs were photographed; images were transferred to a computer and enlarged 6 times. Printouts of the images were taken and the torque expression angle for each tooth of the two groups was measured. A wide range of torque expression was obtained reflecting the influence of tooth morphology on the expression of torque, suggestive of significant variations in the tooth morphology of the same tooth type. However, the mean torque expressions obtained in this study were comparable to the average values of torque prescribed for the two prescriptions.