Evaluating the impact of attachment designs on canine derotation in clear aligner therapy: a finite element analysis

BACKGROUND: Successful canine derotation in Clear Aligner Therapy (CAT) relies on strategic attachment design, influencing force direction and root control. This study employs Finite Element Analysis (FEA) to compare the biomechanical efficacy of three attachment designs, aiming to optimize treatment strategies for canine derotation. METHODOLOGY: A three-dimensional finite element model of the maxillary arch was developed to simulate the rotational movement of maxillary canine in CAT. Three attachment groups used for evaluation were- VL: Vertical-angulated labial attachments only, VLP: Vertical-angulated labial and palatal attachments, VLPPP: Vertical-angulated labial attachments with palatal pressure points. Incremental rotational force of 10, 20, 30, 40 degrees was applied across all three groups. Tooth displacement, attachment deformation, periodontal ligament (PDL) stress and alveolar bone stress were analyzed and compared using ANSYS simulation software. RESULTS: VLPPP showed the highest tooth displacement pattern of 0.017 mm with incremental rotational force application but also exhibited highest stress concentration at PDL and alveolar bone level of 516.10 Mpa. VL showed the least tooth movement of 0.012 mm and lowest stress levels of 374.33 Mpa. CONCLUSION: VLPPP generated the highest force output, but also induced the greatest biological stress. In contrast, VLP with dual surface attachments effectively facilitated tooth movement while minimizing biological stress. Multi-surface force application enhances biomechanical control in clear aligner canine derotation.