Bracket Positioning Techniques and Quality of Orthodontic Finishing

July 10, 2026 updated by: Hager Mansour Abdelbaseer Zoghby, Future University in Egypt

Comparison of Three Bracket Positioning Techniques (Smile Arc Protection, Smile Arc and Marginal Ridge Approach, and McLaughlin-Bennett-Trevisi) on the Quality of Orthodontic Finishing, Mini-Esthetics, and Anterior Tooth Tip and Torque: A Three-Arm Randomized Clinical Trial

This three-arm randomized clinical trial compares three orthodontic bracket positioning techniques - Smile Arc Protection (SAP), Smile Arc and Marginal Ridge Approach (SAMRA), and the McLaughlin-Bennett-Trevisi (MBT) bracket placement chart (control) - in young patients with Angle Class I malocclusion and mild-to-moderate crowding treated non-extraction. The primary aim is to determine which technique yields the highest quality of orthodontic finishing, measured with the American Board of Orthodontics Objective Grading System (ABO-OGS). Secondary aims compare anterior tooth tip and torque (assessed by CBCT) and mini-esthetic smile parameters (gingival display, incisal display, buccal corridor, and smile arc, assessed on standardized posed-smile photographs) among the three techniques.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Bracket positioning is one of the most influential operator-dependent factors affecting the quality of orthodontic finishing and the resulting smile esthetics. Three contemporary positioning philosophies are compared in this trial.

Design. Eligible participants are randomly allocated 1:1:1 to one of three parallel arms. Allocation is generated with an online randomizer, concealed in sequentially opaque sealed envelopes held by a co-supervisor, and revealed only on the day of intervention. Outcome assessors are blinded; operator blinding is not feasible.

Intervention. All arms receive a fully digital indirect-bonding workflow (intraoral scanning, virtual bracket placement in 3Shape Ortho-Analyzer, 3D-printed casts, vacuum-formed transfer trays) using a 0.018-inch MBT prescription, and an identical arch wire sequence ending in a 0.017 in × 0.025 in stainless steel wire maintained for three months. The arms differ only in the vertical/angular bracket-positioning rule applied (SAP, SAMRA, or MBT chart).

Assessment. Records are captured before bonding (T₀) and at the end of levelling and alignment (T₁). The ABO-OGS is scored on 3D-printed casts and the panoramic radiograph; tip and torque are measured on dentoalveolar CBCT; mini-esthetic parameters are measured on standardized frontal posed-smile photographs calibrated in Adobe Photoshop.

Study Type

Interventional

Enrollment (Actual)

39

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Egypt
    • Cairo Governorate
      • New Cairo, Cairo Governorate, Egypt, 11835
        • Department of Orthodontics, Faculty of Oral and Dental Medicine, Future University in Egypt, Cairo, Egypt

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Males and females aged 14-25 years with a full permanent dentition.
  2. Mild to moderate crowding requiring non-extraction orthodontic treatment (2-6 mm per Graber's classification).
  3. Angle Class I malocclusion.
  4. Normal skeletal vertical dimension (SN-MP angle 32° ± 5°).

Exclusion Criteria:

  • 1. Medication that may cause gingival inflammation (e.g., cyclosporine, phenytoin).

    2. Impacted, extracted, or missing permanent teeth (except third molars). 3. Periodontal disease or parafunctional habits (bruxism, tongue thrusting, mouth breathing).

    4. History of previous orthodontic treatment. 5. Craniofacial anomalies, facial asymmetry, or skeletal discrepancy.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Group SAP
Bracket positioning by the Smile Arc Protection technique (anterior brackets placed relatively more gingival, referenced to canine crown height).
Procedure: Smile Arc Protection (SAP) bracket positioning
Bracket positioning by the Smile Arc Protection technique (anterior brackets placed relatively more gingival, referenced to canine crown height).
Experimental: Group SAMRA
Bracket positioning by the Smile Arc and Marginal Ridge Approach (digital workflow referencing the marginal-ridge line and facial axis).
Procedure: Smile Arc and Marginal Ridge Approach (SAMRA) bracket positioning; Procedure
Bracket positioning by the Smile Arc and Marginal Ridge Approach (digital workflow referencing the marginal-ridge line and facial axis).
Active Comparator: Group MBT (Control)
Bracket positioning by the McLaughlin-Bennett-Trevisi bracket placement chart (bracket-to-incisal-edge distances from the standardized chart).
Procedure: McLaughlin-Bennett-Trevisi (MBT) chart bracket positioning
Bracket positioning by the McLaughlin-Bennett-Trevisi bracket placement chart (bracket-to-incisal-edge distances from the standardized chart).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Quality of orthodontic finishing - ABO Objective Grading System (ABO-OGS) total score
Time Frame: At completion of the levelling and alignment phase (T₁), after the 0.017 in × 0.025 in stainless steel arch wire has been maintained for 3 months - approximately 7 months after bonding.
Total ABO-OGS score obtained on the Cast-Radiographic Evaluation (CRE) form. Seven parameters - alignment/rotations, marginal ridges, buccolingual inclination, occlusal contacts, occlusal relationships, overjet, and interproximal contacts - are scored on 3D-printed casts with the ABO measuring gauge; root angulation is scored on the panoramic radiograph. Point deductions are summed to give the total score (a lower total indicates better finishing).
At completion of the levelling and alignment phase (T₁), after the 0.017 in × 0.025 in stainless steel arch wire has been maintained for 3 months - approximately 7 months after bonding.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Anterior crown angulation (tip) - CBCT
Time Frame: Change from before bonding (T₀) to end of levelling and alignment (T₁), approximately 7 months after bonding
Change in mesiodistal crown angulation (tip) of the anterior teeth, measured in degrees on dentoalveolar CBCT using defined landmarks and reference planes.
Change from before bonding (T₀) to end of levelling and alignment (T₁), approximately 7 months after bonding
Anterior crown inclination (torque) - CBCT
Time Frame: Change from before bonding (T₀) to end of levelling and alignment (T₁), approximately 7 months after bonding
Change in labiolingual crown inclination (torque) of the anterior teeth, measured in degrees on dentoalveolar CBCT.
Change from before bonding (T₀) to end of levelling and alignment (T₁), approximately 7 months after bonding
Maxillary gingival display
Time Frame: Change from before bonding (T₀) to end of levelling and alignment (T₁), approximately 7 months after bonding
Change in maxillary gingival display - the vertical distance (mm) between the inferior border of the upper lip and the gingival zenith of each maxillary anterior tooth (central incisor, lateral incisor, canine, both sides) on standardized posed-smile frontal photographs, measured in Adobe Photoshop after calibration against a metric ruler.
Change from before bonding (T₀) to end of levelling and alignment (T₁), approximately 7 months after bonding
Maxillary incisal display
Time Frame: Change from before bonding (T₀) to end of levelling and alignment (T₁), approximately 7 months after bonding
Change in maxillary incisal display - the vertical amount (mm) of maxillary incisor crown visible relative to the upper lip during a posed smile, on standardized photographs.
Change from before bonding (T₀) to end of levelling and alignment (T₁), approximately 7 months after bonding
Buccal corridor width
Time Frame: Change from before bonding (T₀) to end of levelling and alignment (T₁), approximately 7 months after bonding
Change in buccal corridor (lateral negative space) - the linear distance (mm) between the most posterior visible maxillary tooth and the corner of the mouth during posed smile, measured on each side and averaged.
Change from before bonding (T₀) to end of levelling and alignment (T₁), approximately 7 months after bonding
Smile arc category
Time Frame: Change from before bonding (T₀) to end of levelling and alignment (T₁), approximately 7 months after bonding
Smile arc classified as consonant, flat, or reversed based on the relationship between the curvature of the maxillary incisal/canine/premolar edges and the curvature of the lower lip during posed smile.
Change from before bonding (T₀) to end of levelling and alignment (T₁), approximately 7 months after bonding

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Future University in Egypt

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

July 1, 2024

Primary Completion (Actual)

July 1, 2026

Study Completion (Actual)

July 1, 2026

Study Registration Dates

First Submitted

July 7, 2026

First Submitted That Met QC Criteria

July 10, 2026

First Posted (Actual)

July 16, 2026

Study Record Updates

Last Update Posted (Actual)

July 16, 2026

Last Update Submitted That Met QC Criteria

July 10, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • FUE.REC(42)/10-2024

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

Study data are stored confidentially within the Department of Orthodontics with access restricted to the investigator and supervisors; results will be disseminated through the institutional thesis repository and peer-reviewed publication.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Malocclusion, Angle Class I

Clinical Trials on Smile Arc Protection (SAP) bracket positioning

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Gambia

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

3
Subscribe