An interventional study of Bidimensional Bracket System and Hybrid Dual-Section Archwire in CLASS II DIVISION 1 MALOCCLUSION, sponsored by Damascus University. Completed at 1 site in Syria. Open to participants aged 18 Years to 30 Years. Per ClinicalTrials.gov, last updated 2026-10-30.
Sponsored by Damascus University · Not applicable, Interventional, and Treatment
External apical root resorption is a possible side effect of fixed orthodontic treatment, particularly in the upper front teeth. This randomized clinical trial was conducted to compare the amount and timing of root resorption associated with three different methods of retracting the upper anterior teeth using miniscrew anchorage. Sixty adult patients with Class II Division 1 malocclusion who required extraction of the upper first premolars were randomly allocated to one of three groups: a bidimensional bracket group, a hybrid dual-section archwire group, or a conventional sliding mechanics group. In all groups, the six upper anterior teeth were retracted together with the support of orthodontic miniscrews. Panoramic radiographs were obtained before treatment, after completion of leveling and alignment, and after completion of en-masse retraction. Root and crown lengths were measured on these radiographs to estimate external apical root resorption during the leveling and alignment phase, during the retraction phase, and over the complete observation period. The study also compared the pattern of resorption among the upper canines, lateral incisors, and central incisors.
Orthodontic camouflage treatment of adult patients with Class II Division 1 malocclusion frequently involves extraction of the maxillary first premolars followed by retraction of the upper anterior teeth. Temporary orthodontic miniscrews can provide skeletal anchorage during this stage and allow the six maxillary anterior teeth to be retracted together as one unit. Although these mechanics are widely used, the anterior teeth remain exposed to orthodontic forces during both the initial leveling and alignment phase and the subsequent retraction phase. External apical root resorption is therefore an important biological safety outcome that should be evaluated throughout treatment rather than only after space closure has been completed.
This single-center, three-arm, parallel-group randomized clinical trial was conducted at the Department of Orthodontics, Faculty of Dentistry, Damascus University. Sixty adult patients with Class II Division 1 malocclusion who required extraction-based orthodontic camouflage treatment were allocated equally to one of three treatment groups: a bidimensional bracket group, a hybrid dual-section archwire group, or a conventional sliding mechanics group.
The three approaches differed in the relationship between the anterior brackets and the working archwire. The bidimensional approach used smaller anterior bracket slots with larger posterior slots. The hybrid dual-section approach used a customized archwire with different anterior and posterior cross-sections, while the conventional group used a continuous archwire with a uniform cross-section. These mechanical differences may influence archwire engagement, force expression, and the distribution of forces applied to the roots of the maxillary anterior teeth. Their possible effect on external apical root resorption therefore required direct clinical comparison.
All participants underwent bilateral extraction of the maxillary first premolars, fixed-appliance leveling and alignment, and miniscrew-supported en-masse retraction of the six maxillary anterior teeth. The same general treatment stages and skeletal anchorage concept were used in all groups, while the bracket-slot and archwire configurations varied according to group allocation. Retraction continued until an acceptable overjet and a Class I canine relationship were achieved. Participants were reviewed regularly throughout treatment, and miniscrew-related or other treatment-associated adverse events were recorded.
Digital panoramic radiographs were obtained before orthodontic treatment, at the end of leveling and alignment immediately before retraction, and after completion of en-masse retraction. The maxillary central incisors, lateral incisors, and canines on both sides were assessed individually. Crown length was used as a stable reference to correct for differences in radiographic magnification between time points.
The study was designed to determine whether the three treatment approaches were associated with different amounts of external apical root resorption and to identify the treatment phase during which root shortening occurred. Resorption was therefore evaluated separately during leveling and alignment, during en-masse retraction, and across the complete observation period. This phase-specific design was intended to avoid attributing all root changes detected at the end of retraction to the retraction mechanics alone.
124 studies on the registry are indexed under Malocclusion, Angle Class II; 19 are open to participants now.
This study's enrollment of 60 is above the median of 34 across 115 interventional studies indexed under Malocclusion, Angle Class II.
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Participants were treated using a bidimensional fixed orthodontic appliance during leveling, alignment, and en-masse retraction.
Procedure: Bidimensional Bracket System
Participants were treated using a hybrid dual-section archwire during miniscrew-supported en-masse retraction.
Procedure: Hybrid Dual-Section Archwire
Participants were treated using conventional fixed orthodontic sliding mechanics during miniscrew-supported en-masse retraction.
Procedure: Conventional Sliding Mechanics
Fixed orthodontic treatment was performed using 0.018-inch slot brackets from canine to canine and 0.022-inch slot brackets on the posterior teeth. After leveling and alignment, en-masse retraction was performed on a 0.018 × 0.025-inch stainless-steel archwire using bilateral orthodontic miniscrews and nickel-titanium closed-coil springs delivering 250 g of force per side.
Fixed orthodontic treatment was performed using 0.022-inch slot brackets. En-masse retraction was carried out using a customized stainless-steel archwire consisting of a 0.019 × 0.025-inch anterior section and 0.016 × 0.022-inch posterior sections, with the transitions located distal to the maxillary canines. Bilateral orthodontic miniscrews and nickel-titanium closed-coil springs delivering 250 g per side were used.
Fixed orthodontic treatment was performed using 0.022-inch slot brackets. En-masse retraction was carried out on a continuous 0.019 × 0.025-inch stainless-steel archwire using bilateral orthodontic miniscrews and nickel-titanium closed-coil springs delivering 250 g of force per side.
External Apical Root Resorption of the Maxillary Anterior Teeth
External apical root resorption was assessed separately for the six maxillary anterior teeth by measuring changes in corrected root length on digital panoramic radiographs using ImageJ software. Crown length was used as a stable reference to correct for differences in radiographic magnification. Root resorption was expressed in millimeters, and the total amount was calculated directly from the initial and final radiographs rather than by adding the interval measurements.
Time frame: Time 0: before the initiation of orthodontic treatment; Time 1: after the leveling and alignment stage, which is expected to occur within approximately four months; Time Final: after the en-masse retraction stage, which is expected to occur within 1 year
Plan to share: No
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Malocclusion, Angle Class II →