Root Resorption and Alveolar Bone Changes in the Maxillary Canine Retraction Using NiTi Closed-Coil Springs Versus Elastomeric Chains: A Split-Mouth Trial.

Aim: To compare apical root resorption and alveolar bone changes induced by the maxillary canine closure procedure performed on patients with Angle Class I malocclusion using NiTi closed-coil springs versus elastomeric chains.

Materials and methods: Thirty-one adult patients who had been instructed to undergo bilateral maxillary first premolar extraction completed a randomized clinical trial split-mouth study with a double-blind design. Elastomeric chains will be used on the left side, and NiTi closed-coil springs will be used on the right side for patients with even numbers. Elastomeric chains will be used on the right side of patients with an odd number, whereas NiTi closed-coil springs will be used on the left side of patients. For each patient, cone-beam computed tomography of the maxillary canine and lateral cephalometric radiographs were carried out before and after treatment to evaluate apical root resorption and perform cephalometric measurements.

Result: The tooth root length decreased by 0.90 ± 0.60 mm in the NiTi closed-coil spring group. The alveolar bone level increased by 0.53 ± 0.66 mm on the buccal side and by 0.79 ± 0.72 mm on the lingual side. These changes were statistically significant (P < 0.001). In the elastomeric chain group, the tooth root length was decreased by 0.92 ± 0.69 mm, and the levels of vertical buccal and lingual alveolar bone increased significantly (P < 0.001). Compared to NiTi closed-coil springs and elastomeric chain groups, there was a 0.03 ± 0.878 mm difference in the tooth root length; however, this difference was not statistically significant (P = 0.878).

Conclusion: Elastomeric chains and NiTi closed-coil springs both generated tooth root resorption, but the results were comparable and the difference was not statistically significant. There was no statistically significant difference between the elastomeric chain and NiTi closed-coil spring groups regarding the changes in alveolar bone loss around the maxillary canines.