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Objectives To compare canine retraction using NiTi closed coil springs vs elastomeric chains comprehensively in a split-mouth randomized controlled trial. Materials and Methods The canines in 64 quadrants were randomly retracted into the first premolar extraction spaces using NiTi closed coil springs or elastomeric chains, in the maxilla and mandible. The retraction force was 150 g. Cone beam computed tomography scans and study models were obtained before the start of canine retraction and 6 months later. The rate and total amount of canine retraction, canine rotation, tipping, and root resorption were evaluated. A visual analogue scale was used to evaluate patients' pain experience. Results The two methods were statistically similar for dental changes, rate of canine retraction, and root resorption. However, patients reported significantly more days of pain with the elastomeric chain compared to the NiTi closed coil springs. Conclusions Within the constraints of the current study, using either NiTi closed coil springs or elastomeric chains as force delivery systems for canine retraction results in no significant difference in the rate of canine retraction, tipping, rotation, or root resorption. Pain experience during retraction using elastomeric chains is more significant yet needs further investigation.

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Background Extraction of the first premolar followed by canine retraction into the extraction space is a common treatment in orthodontics. Molar rotation occurs when they are used as anchorage units for the canine distalization. The aim of this single-arm clinical trial was to evaluate the maxillary first molar rotation during maxillary canine retraction with elastic power chains and direct miniscrew anchorage. Results The mean difference between pre-retraction and post-retraction molar rotation was 1.89° ± 0.6 which was statistically insignificant. Conclusion The use of miniscrews for direct anchorage can eliminate unwanted rotation of the maxillary first molars during canine retraction. Trial registration ClinicalTrials.gov, NCT04887974. Registered on May 6, 2021- Retrospectively registered https://clinicaltrials.gov/ct2/show/NCT04887974?id=NCT04887974&draw=2&rank=1.

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Background: During canine retraction, orthodontic forces are applied away from the tooth's center of resistance. This introduces canine distal tipping and mesiobuccal rotation. The correction of these unwanted movements will prolong treatment time. Applying the force closer to the center of resistance should decrease this unwanted tooth movement.Objective: Compare the canine angulation and rotation during canine retraction with and without the use of power arm. Materials and Methods:Twenty-four female orthodontic patients (age 19.32± 4.17 years) with dental Class II indicated for bilateral maxillary first premolar extraction and maximum anchorage were included in this study. The canines were retracted with elastomeric chains over 0.017 × 0.025" statinless steel arch wires to reduce friction. The retraction force was 150g. In twelve patients, the canines were retracted using a power arm fixed to the vertical slots of the canine brackets. For the other twelve patients, the elastic chains were attached to the bracket hooks.Results: Before treatment, the canine angulation and rotation was similar for the two groups. The canine angulation was 12.38± 8.27 and 14.5º± 9.41 for the group with the power arm and without, respectively. while canine rotation was 64.74º± 11.65 and 63.12º± 14.88, respectively. Post-retraction, there was no significant difference in the canine angulation or rotation between the groups. Conclusion:Compared to canine retraction with a power arm, conventional canine retraction with elastomeric chains attached to the bracket hook may provide similar control over distal tipping, provided a stiff 0.017" X 0.025" stainless steel arch wire is used.

Background: In extraction cases, canine torque is of primary importance. Failure to maintain the root within the cancellous bone predisposes to root resorption and periodontal breakdown. Positive torque in the bracket or wire may prevent the proximity of the root and cortical bone as well as the subsequent side effects. Objective:The aim of this study was to evaluate the torque control provided by 0.022" Roth prescription brackets during canine retraction with sliding mechanics. Materials and methods:Twenty-one patients (19.2 ± 2.7 years) with various malocclusions involving canine retraction were included in the trial. Cone beam computer tomography was acquired before and six months after the start of canine retraction. The change in canine torque was calculated from the pre-and post-retraction 3-dimensional images. Torque was measured for maxillary and mandibular canines as the angle between the canine's long axis and the mid-sagittal plane. The paired t-test was used to evaluate the change in torque.Results: Statistically significant increase in the angle occurred for the maxillary (3.088±5.627°) and mandibular (2.971±5.427°) canines. Conclusion:Canines could express labial crown inclination during retraction despite the absence of a positive built-in bracket torque.