This study aims to provide a preliminary clinical evaluation of a novel bi-dimensional archwire used during miniscrew-supported en-masse retraction of the maxillary anterior teeth. Adult patients with Class II Division 1 malocclusion requiring extraction of the maxillary first premolars will be screened at the Department of Orthodontics, Faculty of Dentistry, Damascus University. Eligible participants will receive fixed orthodontic treatment followed by en-masse retraction using a custom-made laser-welded bi-dimensional stainless-steel archwire consisting of a 0.019 × 0.025-inch anterior segment and 0.016 × 0.022-inch posterior segments. Retraction will be supported by orthodontic miniscrews and nickel-titanium closed-coil springs. The main outcome will be the monthly rate of maxillary anterior retraction assessed on three-dimensional digital dental models. A secondary outcome will be the change in maxillary incisor torque assessed on lateral cephalometric radiographs. This pilot study is intended to generate preliminary clinical data regarding the feasibility and performance of this novel archwire design.
This study was designed as a prospective single-arm pilot clinical trial to provide an initial clinical evaluation of a novel bi-dimensional archwire specifically developed for miniscrew-supported en-masse retraction of the maxillary anterior teeth. In adult orthodontic patients requiring extraction-based treatment, effective space closure depends not only on anchorage control, but also on the ability of the active retraction system to maintain acceptable control of the maxillary incisors during sliding mechanics. Conventional continuous rectangular stainless-steel archwires provide rigidity, but they may still be associated with frictional resistance, wire deformation, and incomplete torque control during retraction. The archwire investigated in this study was newly developed as a single continuous stainless-steel assembly composed of a 0.019 × 0.025-inch anterior segment and 0.016 × 0.022-inch posterior segments joined by laser welding. The design was intended to combine greater anterior stiffness, to support better torque control of the maxillary incisors, with reduced posterior friction and binding during sliding mechanics. The intervention was applied under direct skeletal anchorage using self-drilling orthodontic miniscrews inserted bilaterally between the maxillary second premolars and first molars. Retraction was performed using nickel-titanium closed-coil springs delivering approximately 250 g of force per side. Eligible participants were adult patients with skeletal Class II malocclusion and Class II Division 1 dental malocclusion who required extraction of the maxillary first premolars and en-masse retraction of the maxillary anterior teeth as part of their treatment plan. After leveling and alignment, the novel bi-dimensional archwire was inserted and the retraction phase was initiated. Participants were followed prospectively until completion of the en-masse retraction phase. The primary outcome of the study was the monthly rate of maxillary anterior en-masse retraction assessed on three-dimensional digital dental models. The secondary outcome was the change in maxillary incisor torque measured on standardized lateral cephalometric radiographs using the bracket-archwire angle. This pilot trial was undertaken to determine whether this newly developed archwire could function as a clinically feasible biomechanical option and to generate preliminary outcome estimates for future randomized controlled trials.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
6
The retraction procedure is going to be conducted using a bi-dimensional archwire which is a single continuous stainless-steel assembly composed of a 0.019 × 0.025-inch anterior segment and 0.016 × 0.022-inch posterior segments joined by laser welding.
Department of Orthodontics, Faculty of Dentistry, University of Damascus
Damascus, Syria
Change in the monthly rate of maxillary anterior en-masse retraction
The amount of maxillary anterior retraction is assessed on three-dimensional digital dental models using the distance between the incisal edge of the maxillary central incisors and the medial point of the third palatal rugae as a stable intraoral reference. The monthly retraction rate is calculated in millimeters per month by dividing the amount of anterior retraction by the corresponding duration of the retraction interval.
Time frame: Time 0: completion of leveling and alignment which happens within three months); Times 1, 2, 3, 4, 5 after one, two, three, four, and five months following the end of the leveling and alignment stage; Time Final: at the end of the retraction stage.
Change in maxillary incisor torque
Maxillary incisor torque is assessed on standardized lateral cephalometric radiographs using the bracket-archwire angle. A tangent is drawn along the base of the maxillary central incisor bracket, and another tangent is drawn parallel to and superimposed on the working archwire. The obtuse angle formed between the two tangents is measured, and the actual torque value is calculated by subtracting 90° from this angle. The change in torque is determined by comparing the measurements recorded at T0 and T1.
Time frame: Time 0: completion of leveling and alignment stage which is expected to occur within three months, and Time Final: completion of en-masse retraction stage which occurs within 9 - 10 months following the end of the leveling and alignment stage.
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