Effectiveness of Sliding Mechanics on a Hybrid Round-Rectangular Archwire for Maxillary Canine Retraction, Angulation Control, Root Resorption, Pain, and Patient Satisfaction in Adult Class II Division 1 Patients: A Preliminary Pilot Study.

BACKGROUND AND OBJECTIVE: Optimizing orthodontic tooth movement while minimizing complications remains a primary goal for both clinicians and patients. This preliminary study evaluated canine retraction using the sliding technique on a round cross-section archwire, employing a hybrid archwire designed to enhance movement efficiency while controlling canine angulation during retraction. This hybrid design combines a rectangular anterior segment for incisor control with a round posterior segment to reduce friction during canine retraction, differing from conventional single-section wires.

METHODS: This study was conducted at the University of Damascus from October 2022 to May 2023 with six patients diagnosed with Class II, Division I malocclusion (mean age: 21.18 ± 2.16 years). After premolar extractions, evaluation focused on the retraction of the right and left canines. A custom hybrid archwire was used, featuring a 0.021 × 0.025-inch rectangular section for the incisor brackets and a 0.020-inch round section for the canine, premolar brackets, and molar tubes. The study assessed the rate of retraction, angulation changes, root resorption, and patient-related outcome measures (PROMs) until a Class I relationship was achieved. Model casts were digitally scanned and analyzed in 3D using Blender® 4.4 to quantify movement, standard lateral cephalometric images (T1 and T2) were obtained to assess angulation changes, panoramic radiographs (T1 and T2) were used to evaluate root resorption, and questionnaires using VAS were administered for PROMs.

RESULTS: The overall mean retraction rate was 1.28 ± 0.13 mm/month. The mean canine retraction rates were 1.46 ± 0.13, 1.42 ± 0.16, and 1.43 ± 0.16 mm/month in the first, second, and third months, respectively. The average retraction time was 4.38 ± 0.75 months, the mean canine angulation change was 5.05 ± 2.03 degrees, the mean canine root resorption was 1.01 ± 0.44 mm, and patient satisfaction was high, with an average score of 93.67.

CONCLUSION: Sliding on a 0.020-inch round cross-section archwire can significantly increase the retraction speed of the upper canines while minimizing changes in canine angulation during retraction, with minimal resorption and high satisfaction. However, further validation is needed to confirm its clinical efficacy.