Comparing two methods of orthodontics space closure: a randomized clinical trial

The objective of this study was to compare the differences inbilateral asymmetry and therate of space closure in the upper arch between NiTi coil springs and the elastomeric module in adolescent patients. Forty-two adolescent patients with bilateral first premolar extractions in the maxillary arch were enrolled and randomly distributed into the NiTi coil spring group and the elastomeric module group. After aligning and leveling with 0.019x0.025-inch stainless steel archwire, the same initial force was applied in the two groups. Dental casts were made at the beginning of space closure (T1) and the end of retraction (T2). The amount of space closure was measured with adigital caliper. Different ratesof space closure and bilateral asymmetric space closure of the two methods were calculated. The mean rate of space closure in the NiTi spring was significantly higher than the elastomeric module. However, bilateral asymmetric space closure with the elastomeric modulewas more significant than the NiTi spring. To conclude, our research suggested that the NiTi coil spring might be a more efficientforce delivery appliancein orthodontic space closure.