| Popis: |
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 0.016” X 0.022” 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. |
