A comparison of elastomeric auxiliaries versus elastic thread on premolar extraction site closure: an in vivo study.

Twenty-five patients requiring symmetric premolar extractions (representing eighty quadrants requiring canine retraction) were entered into the study. Standard 0.022 X 0.028-inch Siamese edgewise appliances with 0.016 X 0.022-inch arch wires were used during canine retraction. In 30 of the quadrants, canine retraction was accomplished with Unitek Alastik chain; 10 quadrants were treated with Rocky Mountain energy chain (medium). In the remaining 40 groups, canine retraction was accomplished via Unitek nylon-covered latex thread. The forces initially applied to the system were between 350-400 grams. Patients were seen at 3-week intervals to measure the amount of space closure and to change the elastic modules. A comparison among the three groups revealed no significant differences in rates of canine retraction (P less than 0.05). Empirically, the elastomeric auxiliaries were found to be more hygienic and required less chair time to apply than did the elastic thread.