Comparison of Root Resorption in Modified Corticotomy-Assisted and Conventional Canine Retraction

Official title

Comparison of External Apical Root Resorption in Modified Corticotomy-Assisted and Conventionally Retracted Maxillary Canines Using Frictionless T-Loop Mechanics: A Randomized Controlled Clinical Trial

Overview

This randomized controlled clinical trial will compare external apical root resorption in patients undergoing maxillary canine retraction using modified corticotomy-assisted frictionless T-loop mechanics versus conventional frictionless T-loop mechanics. Sixty orthodontic patients requiring extraction of maxillary first premolars will be randomly assigned to two groups. Changes in canine root length will be measured on panoramic radiographs taken before and after retraction to determine the extent of external apical root resorption. The study will evaluate whether modified corticotomy-assisted retraction results in different root resorption outcomes compared to conventional retraction.

Detailed description

External apical root resorption is a known complication of orthodontic treatment and may be influenced by the magnitude and duration of orthodontic force. Methods that accelerate tooth movement may reduce overall treatment time and potentially influence the extent of root resorption.

Corticotomy-assisted orthodontics is based on the regional acceleratory phenomenon, which enhances bone remodeling and facilitates tooth movement. Modified corticotomy techniques involve limited surgical injury to the cortical bone to stimulate accelerated movement while minimizing postoperative morbidity. Frictionless mechanics using T-loops allow controlled canine retraction with reduced frictional resistance between the bracket and archwire.

This single-center randomized controlled clinical trial will enroll 60 patients aged 12 to 30 years who require bilateral extraction of maxillary first premolars as part of orthodontic treatment. Participants will be randomly allocated in a 1:1 ratio to:

Group A: Modified corticotomy-assisted canine retraction with frictionless T-loop mechanics Group B: Conventional frictionless T-loop canine retraction

All participants will be treated using 0.022 × 0.028-inch preadjusted edgewise appliances. Standardized T-loop activation delivering controlled force will be performed at three-week intervals until canine retraction is completed.

External apical root resorption will be assessed by measuring linear changes in root length from the canine cusp tip to the root apex on calibrated pre- and post-retraction panoramic radiographs using digital measurement software. The primary outcome measure will be the mean change in root length between baseline and post-retraction assessments. Statistical analysis will compare the magnitude of root resorption between the two groups.

Interventions

• Procedure Modified Corticotomy assisted frictionless canine retraction
  A surgical procedure in which a buccal flap is elevated and two vertical corticotomy cuts are made in the maxillary cortical bone adjacent to the extraction site to accelerate orthodontic tooth movement.
• Procedure Conventional Frictionless Canine retraction
  Orthodontic space closure using 17×25 TMA T-loops activated to deliver approximately 200 g of force for frictionless canine retraction into maxillary first premolar extraction spaces.

Primary outcome measures

• Mean Loss of Canine Root Length (mm) [Time frame: - Before retraction (baseline) - From baseline to completion of canine retraction (approximately 4-6 months)]

Secondary outcome measures (1)

• Change in Root Width at Mesial and Distal Apex (mm) [Time frame: From baseline to completion of canine retraction (approximately 4-6 months)]

Eligibility criteria

Inclusion criteria

• Patients aged 12-30 years requiring canine retraction into maxillary first premolar extraction spaces
• Patients with normal vertical skeletal pattern (mandibular plane angle 32° ± 5°)
• Patients with healthy periodontium

Exclusion criteria

• Syndromic patients
• Patients with systemic conditions requiring long-term medication affecting orthodontic tooth movement (e.g., NSAIDs, bisphosphonates, anticonvulsants)
• Mixed dentition cases
• Patients with pre-existing root resorption
• Patients who fail to attend scheduled appointments

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Single blind

Primary purpose

Prevention

Study locations

Pakistan · 1 center

• Islamabad Dental Hospital — Islamabad

Publications

• Sondeijker CFW, Lamberts AA, Beckmann SH, Kuitert RB, van Westing K, Persoon S, Kuijpers-Jagtman AM. Development of a clinical practice guideline for orthodontically induced external apical root resorption. Eur J Orthod. 2020 Apr 1;42(2):115-124. doi: 10.1093/ejo/cjz034. PMID 31087032
• Hatrom AA, Zawawi KH, Al-Ali RM, Sabban HM, Zahid TM, Al-Turki GA, Hassan AH. Effect of piezocision corticotomy on en-masse retraction. Angle Orthod. 2020 Sep 1;90(5):648-654. doi: 10.2319/092719-615.1. PMID 33378476
• Alikhani M, Raptis M, Zoldan B, Sangsuwon C, Lee YB, Alyami B, Corpodian C, Barrera LM, Alansari S, Khoo E, Teixeira C. Effect of micro-osteoperforations on the rate of tooth movement. Am J Orthod Dentofacial Orthop. 2013 Nov;144(5):639-48. doi: 10.1016/j.ajodo.2013.06.017. PMID 24182579

Identifiers

NCT: NCT07458139 · IDH123 · IDH-ORTHO-2026

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗