A clinical and radiographic study to evaluate the rate of retraction of maxillary canine using nickel-titanium closed coil spring with two different bracket systems

Abstract

Objectives: This study compares the efficiency of self-ligating brackets with the conventional preadjusted edgewise (PEA) brackets during maxillary canine retraction using nickel-titanium closed coil springs. Materials and Methods: The sample comprised of 20 healthy patients (10 males and 10 females), within age groups 16-26 years (mean, 20 years) having Class I malocclusion with bimaxillary protrusion. All patients underwent bilateral extraction of the maxillary first bicuspids and retraction of the maxillary canines with fixed self-ligating brackets (3M Smart clip) and PEA appliance (3M Gemini). The initial records included standard intra- and extra-oral photographs, study models, lateral cephalograms, and panoramic radiographs. Results: The mean distal movement of canines in self-ligating brackets was 0.89 mm/mo with standard deviation of 0.255 and in preadjusted edgewise brackets, the mean distal movement of canines was 0.87 mm/mo with standard deviation of 0.214. The mean tipping of canine in self-ligating brackets was 7.45 ± 1.050(0) and in PEA brackets it was 7.70° ± 1.21°. The mean rotation of canine in self-ligating brackets was 7.65° ± 3.47° and in preadjusted edgewise appliance it was 12.30° ± 3.08°. Conclusion: The rates of distal movement of the maxillary canines were similar with both conventional and self-ligating brackets. Rotation of the maxillary canines during retraction was minimized with self-ligating brackets in comparison to conventional bracket systems.