Erdem, BuketÖzcan, MustafaŞar, Çağla2026-01-242026-01-242025Erdem, B., Özcan, M., & Şar, Ç. (2025). Evaluation of mesiodistal tip accuracy in mandibular anterior teeth following incisor extraction with clear aligners. Journal of the World Federation of Orthodontists, 14(6), pp. 571. https://doi.org/10.1016/j.ejwf.2025.07.5382212-4438https://doi.org/10.1016/j.ejwf.2025.07.538https://hdl.handle.net/20.500.13055/1270Introduction: Single mandibular incisor extraction is sometimes necessary in clear aligner treatment, yet the accuracy of mesiodis tal tooth positioning in such cases remains unclear. This retro spective study evaluates the discrepancy between predicted and achieved mesiodistal movements of the remaining mandibular an terior teeth in Invisalign (Align Technology, Santa Clara, CA) treat ments. Additionally, it examines the effects of aligner attachments and change frequency on movement accuracy. Material and Methods: A total of 40 Invisalign patients with single mandibular incisor extraction were retrospectively analyzed. Geomagic Control X (3D Systems, Rock Hill, SC) was used to mea sure pretreatment positions, predicted movements, and achieved outcomes. Predicted and actual mesiodistal tip movements were compared. Results: Regression analysis revealed significant discrepancies (P < 0.001) between predicted and achieved mesiodistal movements for both incisors and canines. Only 70% of the predicted incisor tip movement (R² = 0.4171) and 60% of the predicted canine tip move ment (R² = 0.5789) were achieved. Neither the number of aligners, change protocol (1-week vs. 2-week), nor attachments significantly affected accuracy (P > 0.05). However, incisors were less likely than canines to follow the predicted movement direction (P = 0.025). Conclusion: A significant discrepancy exists between predicted and achieved mesiodistal movements after single mandibular in cisor extraction with Invisalign. The number of aligners, wear dura tion, and attachments do not significantly influence accuracy. Fur ther research is needed to optimize treatment planning and im prove predictability in clear aligner therapy.eninfo:eu-repo/semantics/closedAccessArticle10.1016/j.ejwf.2025.07.538146571571Q1Q1