Effects of Power Arm Application in Maxillary Canine Distalization

NCT07866976 | Completed

• 1 other identifier: OMU-KAEK-2023/260
• Study Type: interventional
• Target: 16
• Locations: 1 country
• Sites: 1

Brief Summary

The aim of this study is to investigate the effects of a canine distalization force applied between power arms placed on the maxillary canine and first molar, in comparison with the classical method without power arms. Following maxillary first premolar extraction, canine distalization is commonly accompanied by undesirable effects such as distal tipping and distopalatal rotation of the canine and mesial movement (anchorage loss) of the first molar. By bringing the applied force closer to the teeth's centers of resistance through power arms, the study seeks to move the canine into the extraction space as close to parallel (bodily) movement as possible. The hypothesis is that applying force with Ni-Ti closed-coil springs between power arms placed on the molar and canine teeth reduces undesirable dental effects such as rotation, tipping and anchorage loss during distalization compared with the classical method. In a split-mouth design, 16 patients with maxillary first premolar extractions and moderate anchorage requirement receive power-arm mechanics on one randomly selected side (study side) and conventional mechanics on the other side (control side), with a 150 g force on both sides, over three months of canine distalization.

Conditions

Malocclusion; Angle Class II; Tooth Movement Techniques; Orthodontic Anchorage Procedures

Keywords

canine retraction; power arm; anchorage loss; split-mouth; closed-coil spring; center of resistance

Outcome Measures

Primary Outcomes (1)

• Canine distalization

  Distal movement of the maxillary canine cusp tip (mm), measured on superimposed 3D digital models as the distance between successive cusp-tip projections on a reference line parallel to the midpalatal raphe. Reported per month and cumulatively.

  Baseline (T0), 1, 2 and 3 months of retraction; cumulative T0 to 3 months

Secondary Outcomes (3)

• First molar anchorage loss

  Baseline (T0), 1, 2 and 3 months; cumulative T0 to 3 months

• Canine rotation

  Baseline (T0), 1, 2 and 3 months; cumulative T0 to 3 months

• Canine tipping

  Baseline (T0), 1, 2 and 3 months; cumulative T0 to 3 months

Study Arms (2)

Study side (power arms)

EXPERIMENTAL

Study side (power arms)

Device: Canine and molar power arms

Control side (classical method)

ACTIVE COMPARATOR

Contralateral maxillary canine retracted on the same archwire with a 150 g Ni-Ti closed-coil spring activated between the molar tube hook and the canine bracket hook, without power arms.

Procedure: Conventional canine retraction

Interventions

Canine and molar power arms DEVICE

Molar tube with a power arm and a U-shaped canine power arm bent from 0.016 x 0.022-inch stainless steel wire (gingival opening facing mesially), adjusted to the molar power-arm height; a 9-mm Ni-Ti closed-coil spring is attached between the two power-arm hooks via a 0.010-inch long ligature wire and activated to 150 g measured with a force gauge.

Study side (power arms)

Conventional canine retraction PROCEDURE

9-mm Ni-Ti closed-coil spring delivering 150 g attached directly between the molar tube hook and the canine bracket hook.

Also known as: Sliding mechanics canine retraction

Control side (classical method)

Eligibility Criteria

• Age: 14 Years - 20 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64)

You may qualify if:

• Maxillary skeletal/dental Angle Class II malocclusion
• Indication for fixed orthodontic treatment with bilateral maxillary first premolar extraction and moderate anchorage requirement
• No systemic disease and no medication use
• No congenitally missing or previously extracted maxillary teeth (third molars excepted)
• Good oral hygiene and healthy periodontal tissues

You may not qualify if:

• Systemic disease or medication use
• Anomalies of tooth number or shape in the maxillary dentition
• Inadequate oral hygiene
• Pubertal growth spurt not yet completed
• Previous orthodontic treatment

Sponsors & Collaborators

• Atlas University: lead

Study Sites (1)

Ondokuz Mayıs University, Faculty of Dentistry, Department of Orthodontics

Samsun, 55139, Turkey (Türkiye)

Location

MeSH Terms

Conditions

Malocclusion; Malocclusion, Angle Class II

Condition Hierarchy (Ancestors)

Tooth Diseases; Stomatognathic Diseases

Study Officials

• Selim Arici, DDS, PhD

  Atlas University

  STUDY DIRECTOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: No blinding was described; the power-arm molar tube identifies the study side, and impressions, scanning and all measurements were performed by the same investigator.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Prof. Dr.

Model Details: Split-mouth design: within each participant, the right and left maxillary quadrants were randomly allocated to the experimental (power arm) or control (conventional) canine retraction mechanics. Each of the 16 participants contributes one quadrant to each arm.

Study Record Dates

• First Submitted: October 5, 2026
• First Posted: October 9, 2026
• Study Start: January 22, 2024
• Primary Completion: March 1, 2025
• Study Completion: March 1, 2025
• Last Updated: October 9, 2026

Record last verified: 2026-10

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)