Additional Palatal Force in Maxillary Canine Distalization

NCT07862790 | Completed

• 2 other identifiers: OMU-ORT-2023-2612023/261
• Study Type: interventional
• Target: 16
• Locations: 1 country
• Sites: 1

Brief Summary

In orthodontic treatment involving extraction of the maxillary first premolars, the canine is distalized into the extraction space using sliding mechanics. Because the retraction force is applied at bracket level and therefore at a distance from the centre of resistance of the tooth, the canine tends to rotate distopalatally and to tip in the sagittal plane instead of translating bodily. These side effects lengthen treatment and increase the load on the posterior anchorage teeth. Power arms are used to bring the line of action of the force closer to the centre of resistance. In addition, because the centre of resistance of the maxillary canine lies palatal to the mid-buccolingual axis of the crown, a force applied from the palatal surface generates a rotational moment opposite in direction to that produced by a buccal force. This trial tested whether dividing a constant total distalizing force between the buccal and the palatal surfaces of the canine, so that the two rotational moments oppose one another, produces a more bodily canine movement than applying the whole force from the buccal side alone. The trial used a split-mouth design: in each participant one maxillary quadrant received the whole force from the buccal side and the contralateral quadrant received half the force buccally and half palatally, with the total force identical on both sides. Canine displacement, rotation, tipping and first molar anchorage loss were measured on superimposed digital models over 12 weeks.

Conditions

Malocclusion; Tooth Movement

Keywords

canine distalization; canine retraction; power arm; palatal force; lingual force; sliding mechanics; otrthodontic anchorage; split-mouth

Outcome Measures

Primary Outcomes (1)

• Cumulative maxillary canine distalization

  Linear distance, in millimetres, travelled by the maxillary canine cusp tip in the sagittal direction, measured as the distance between the projections of the cusp tip onto a reference line parallel to the midpalatal suture on digital models superimposed on three palatal rugae landmarks.

  From the start of distalization to 3 months

Secondary Outcomes (3)

• Maxillary canine distopalatal rotation

  From the start of distalization to 3 months

• Maxillary canine mesiodistal tipping

  From the start of distalization to 3 months

• Maxillary first molar anchorage loss

  From the start of distalization to 3 months

Study Arms (2)

Buccal plus palatal force

EXPERIMENTAL

The maxillary quadrant randomly allocated to receive the distalizing force from both the buccal and the palatal surfaces. A nickel-titanium closed-coil spring delivered 100 g between the buccal canine power arm and the buccal first molar power arm, and a second spring delivered 100 g between a palatal canine power arm and a palatal first molar power arm, giving 200 g in total. Sixteen quadrants, one in each participant.

Device: Combined buccal and palatal distalizing force

Buccal force only

ACTIVE COMPARATOR

The contralateral maxillary quadrant, in which the distalizing force was applied only from the buccal surface. A single nickel-titanium closed-coil spring delivered 200 g between the buccal canine power arm and the buccal first molar power arm. Sixteen quadrants, one in each participant.

Device: Buccal distalizing force

Interventions

Combined buccal and palatal distalizing force DEVICE

Canine distalization on a 0.019 x 0.025 inch stainless steel archwire using two 9 mm nickel-titanium closed-coil springs. One spring delivers 100 g between a 7 mm buccal canine power arm in the bracket vertical slot and the power arm of the first molar tube; the second delivers 100 g between a palatal canine power arm, placed in the vertical slot of a bracket bonded to the palatal surface of the canine, and a power-arm tube bonded to the palatal surface of the first molar. Total force 200 g. Forces re-measured and reset every four weeks.

Buccal plus palatal force

Buccal distalizing force DEVICE

Canine distalization on a 0.019 x 0.025 inch stainless steel archwire using a single 9 mm nickel-titanium closed-coil spring delivering 200 g between a 7 mm buccal canine power arm in the bracket vertical slot and the power arm of the first molar tube. Force re-measured and reset every four weeks.

Buccal force only

Eligibility Criteria

• Age: 12 Years - 18 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64)

You may qualify if:

• Indication for fixed orthodontic treatment with bilateral extraction of the maxillary first premolars
• Moderate anchorage requirement
• Complete permanent dentition with radiographically closed maxillary canine apices
• Good oral hygiene, with the ability to maintain it throughout treatment
• Good cooperation with treatment

You may not qualify if:

• Previous extraction of any permanent tooth other than third molars
• Congenitally missing or impacted teeth
• Systemic disease, or regular use of medication, capable of influencing orthodontic tooth movement
• Asymmetry, occlusal discrepancy, jaw trauma or developmental disturbance of a degree requiring orthognathic surgery

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

Condition Hierarchy (Ancestors)

Tooth Diseases; Stomatognathic Diseases

Study Officials

• Selim Arici, DDS, PhD

  Ondokuz Mayıs University

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Prof. Dr. Department of Orthodontics

Model Details: Split-mouth (within-person) design. Both interventions were applied simultaneously in every participant, one to each maxillary quadrant, rather than in successive periods. The unit of randomization and analysis was the maxillary quadrant, and the two quadrants of each participant provide paired observations. There was no washout period, as the interventions ran concurrently on anatomically separate sites.

Study Record Dates

• First Submitted: October 2, 2026
• First Posted: October 7, 2026
• Study Start: January 15, 2024
• Primary Completion: November 4, 2024
• Study Completion: November 4, 2024
• Last Updated: October 7, 2026

Record last verified: 2026-09

Locations

TU (1)