An interventional study of Modified Corticotomy assisted frictionless canine retraction and Conventional Frictionless Canine retraction in External Apical Root Resorption in Maxillary Canines During Orthodontic Retraction, sponsored by Islamabad Medical and Dental College. Not yet recruiting at 1 site in Pakistan. Open to participants aged 12 Years to 30 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-03-09.
Sponsored by Islamabad Medical and Dental College · Not applicable, Interventional, and Prevention
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.
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.
43 studies on the registry are indexed under Root Resorption; 9 are open to participants now.
This study's planned enrollment of 60 is above the median of 29 across 36 interventional studies indexed under Root Resorption.
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Description: Participants will undergo modified corticotomy procedure followed by canine retraction using frictionless T-loop mechanics after extraction of maxillary first premolars. Intervention: * Procedure: Modified Corticotomy * Procedure: Frictionless T-loop canine retraction.
Procedure: Modified Corticotomy assisted frictionless canine retraction
Description: Participants will undergo conventional canine retraction using frictionless T-loop mechanics without any surgical intervention after extraction of maxillary first premolars. Intervention: Frictionless T-loop canine retraction.
Procedure: Conventional 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.
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.
Mean Loss of Canine Root Length (mm)
External apical root resorption measured as the difference in root length (in millimeters) from canine cusp tip to root apex on calibrated pre-treatment and post-retraction OPG radiographs using ViewBox software.
Time frame: - Before retraction (baseline) - From baseline to completion of canine retraction (approximately 4-6 months)
Change in Root Width at Mesial and Distal Apex (mm)
Difference in mesial and distal root width measured 1 mm short of the root apex on calibrated OPG radiographs before and after canine retraction.
Time frame: From baseline to completion of canine retraction (approximately 4-6 months)
Degree of External Apical Root Resorption According to Sharpe Classification
SHARPE ET AL. CLASSIFICATION OF EXTERNAL ROOT RESORPTION 0 = No apical root resorption 1. Slight blunting of the root apex 2. Moderate resorption of root apex beyond blunting and up to one-third of root length. 3. Excessive (severe) resorption of the root apex beyond one-third of the root length.
Time frame: At completion of canine retraction (approximately 4-6 months)
Plan to share: No — IPD will not be shared to maintain participant confidentiality and due to institutional data protection policies.
This study is not yet recruiting, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.
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Islamabad Medical and Dental College