Effectiveness of Mini-screw and Nance palatal arch for anchorage control following segmental maxillary canine retraction in adolescents with angle Class I crowding using 3D digital models: A randomized clinical trial.

Abstract

Objectives: To compare anchorage control and treatment duration between Mini-screws and the Nance palatal arch during segmental canine retraction in adolescents.

Trial design: Two-arm, parallel-group randomized controlled trial.

Methodology: Fifty patients (11-18 years) requiring first premolar extraction were randomly assigned to Group 1 (Nance palatal arch) or Group 2 (Mini-screw) in the ratio of 1:1. Eligibility criteria included Angle's Class I molar relation, tooth material arch length discrepancy more than 10 mm, requiring first premolar extraction. Allocation was concealed using sequentially numbered, opaque, sealed envelopes. Pretreatment and postretraction digital models were analyzed after individual canine retraction with Burstone's T-loop using 3-matic software. t tests were used to assess tooth movement, and the Mann-Whitney test was employed to evaluate treatment duration (P < 0.05).

Results: All 25 patients in the Nance group completed the trial. Two patients in the Mini-screw group were excluded due to screw loosening (n = 23 analyzed). The mean distal canine movement was similar in both groups, but molar mesial movement was significantly lower in Group 2 (0.68 and 0.41 mm) than in Group 1 (1.68 and 1.61 mm). The treatment duration was significantly less Group 2 (173.2 days) compared to Group 1 (186.0 days).

Harms: No harms were reported in the trail.

Conclusion: Although the mesial movement of molars was significantly less for the Mini-screws, the Nance palatal appliance was clinically equally effective in reinforcing the distal movement of canines. The differences in anchorage loss between the two modalities were small, and clinical judgment is thus imperative for decision-making and planning for absolute anchorage with a Mini-screw.