Clinical expression of programmed rotation and uprighting of bilateral winged maxillary central incisors with the Invisalign appliance: A retrospective study

Published:September 22, 2021DOI:


      • Winged incisors present clinically with rotations of maxillary central incisors.
      • Efficacy and accuracy of Invisalign for correction of rotation and tipping were assessed.
      • Invisalign tended to undercorrect rotation and uprighting tooth movements.
      • Overcorrection can also be clinically expressed.


      Winged maxillary central incisors (WMCI), defined as mesiopalatal rotation of the crowns of maxillary central incisors, is a common dental trait that affects smile esthetics. This retrospective study aimed to determine the efficacy of rotation and uprighting tooth movements of bilateral WMCI with Invisalign (Align Technology, Santa Clara, Calif).


      Initial, predicted, and achieved stereolithography files of 30 adult patients, consecutively treated with the Invisalign SmartTrack appliance, were superimposed using Geomagic Control X 64 (3D Systems, Rock Hill, SC). The pairs of incisors were assessed for rotation using the interlabial angle (ILA), and individual incisors were measured for rotation and tip.


      Programmed rotation and uprighting of WMCI are mostly undercorrected with the Invisalign appliance. The mean shortfall in ILA was 10.5° (standard deviation [SD], 10.66; 95% confidence interval [CI], 5.89-14.19; P <0.001) for a mean predicted change of 35.27°. For individual incisors, a mean shortfall of 5.38° (SD, 5.88; 95% CI, 3.58-6.76; P <0.001) was found for a mean 18.75° predicted change in rotation. A mean predicted change in tip of 7.06° showed a mean shortfall of was 2.16° (SD, 3.86°; 95% CI, 1.03-3.01; P <0.001). A moderate and statistically significant correlation between shortfalls in rotation and tip was observed (r = 0.44). Linear regression analysis was used to formulate an equation as a clinical tool to determine the likely achieved outcome on the basis of the predicted change.


      Predicted changes in rotation, ILA, and tip were both under and overexpressed. In particular, tip was dependent on the magnitude of planned change. The random inconsistencies in the clinical expression of rotation and tipping warrant careful monitoring and/or remedial actions such as overcorrections aligners.
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        • Andrews L.F.
        The six keys to normal occlusion.
        Am J Orthod. 1972; 62: 296-309
        • Yang S.
        • Guo Y.
        • Yang X.
        • Zhang F.
        • Wang J.
        • Qiu J.
        • et al.
        Effect of mesiodistal angulation of the maxillary central incisors on esthetic perceptions of the smile in the frontal view.
        Am J Orthod Dentofacial Orthop. 2015; 148: 396-404
        • Kokich Jr., V.O.
        • Asuman Kiyak H.A.
        • Shapiro P.A.
        Comparing the perception of dentists and lay people to altered dental esthetics.
        J Esthet Dent. 1999; 11: 311-324
        • Rothhammer F.
        • Lasserre E.
        • Blanco R.
        • Covarrubias E.
        • Dixon M.
        Microevolution in human Chilean populations: IV. Shovel shape, mesial-palatal version and other dental traits in Pewenche Indians.
        Z Morphol Anthropol. 1968; 60: 162-169
        • Wong R.
        Incisor winging in Chinese..
        Open Anthropol J. 2010; 3: 8-11
        • Scott G.R.
        • Potter R.H.
        • Noss J.F.
        • Dahlberg A.A.
        • Dahlberg T.
        The dental morphology of Pima Indians.
        Am J Phys Anthropol. 1983; 61: 13-31
        • Dahlberg A.
        A wing-like appearance of upper central incisors among American Indians.
        J Dent Res. 1959; 38: 203-204
        • Dahlberg A.
        • Enoki K.
        • Nakamura E.
        Rotated maxillary central incisors.
        J Jap Orthod Soc. 1958; 17: 157-169
        • Pacheco-Pereira C.
        • Brandelli J.
        • Flores-Mir C.
        Patient satisfaction and quality of life changes after Invisalign treatment.
        Am J Orthod Dentofacial Orthop. 2018; 153: 834-841
        • Boyd R.L.
        • Miller R.
        • Vlaskalic V.
        The Invisalign system in adult orthodontics: mild crowding and space closure cases.
        J Clin Orthod. 2000; 34: 203-212
        • Sergl H.G.
        • Klages U.
        • Zentner A.
        Pain and discomfort during orthodontic treatment: causative factors and effects on compliance.
        Am J Orthod Dentofacial Orthop. 1998; 114: 684-691
        • Boyd R.L.
        • Vlaskalic V.
        Three-dimensional diagnosis and orthodontic treatment of complex malocclusions with the invisalign appliance.
        Semin Orthod. 2001; 7: 274-293
        • Melsen B.
        Northcroft lecture: How has the spectrum of orthodontics changed over the past decades?.
        J Orthod. 2011; 38 (quiz 145): 134-143
        • Papadimitriou A.
        • Mousoulea S.
        • Gkantidis N.
        • Kloukos D.
        Clinical effectiveness of Invisalign® orthodontic treatment: a systematic review.
        Prog Orthod. 2018; 19: 37
        • Robertson L.
        • Kaur H.
        • Fagundes N.C.F.
        • Romanyk D.
        • Major P.
        • Flores Mir C.
        Effectiveness of clear aligner therapy for orthodontic treatment: a systematic review.
        Orthod Craniofac Res. 2020; 23: 133-142
        • Galan-Lopez L.
        • Barcia-Gonzalez J.
        • Plasencia E.
        A systematic review of the accuracy and efficiency of dental movements with Invisalign.
        Korean J Orthod. 2019; 49: 140-149
      1. AlignTechnology.
        (Available at:)
        • Gangitano C.G.
        A Correlative Study of Winging and Certain Features of Dental Morphology in a Group of Navajo Indian Children.
        1974 (Master’s thesis. Loyola eCommons)
        • Grünheid T.
        • Loh C.
        • Larson B.E.
        How accurate is Invisalign in nonextraction cases? Are predicted tooth positions achieved?.
        Angle Orthod. 2017; 87: 809-815
        • Simon M.
        • Keilig L.
        • Schwarze J.
        • Jung B.A.
        • Bourauel C.
        Treatment outcome and efficacy of an aligner technique—regarding incisor torque, premolar derotation and molar distalization.
        BMC Oral Health. 2014; 14: 68
        • Keilig L.
        • Piesche K.
        • Jäger A.
        • Bourauel C.
        Applications of surface-surface matching algorithms for determination of orthodontic tooth movements.
        Comput Methods Biomech Biomed Engin. 2003; 6: 353-359
        • Kravitz N.D.
        • Kusnoto B.
        • BeGole E.
        • Obrez A.
        • Agran B.
        How well does Invisalign work? A prospective clinical study evaluating the efficacy of tooth movement with Invisalign.
        Am J Orthod Dentofacial Orthop. 2009; 135: 27-35
        • Charalampakis O.
        • Iliadi A.
        • Ueno H.
        • Oliver D.R.
        • Kim K.B.
        Accuracy of clear aligners: a retrospective study of patients who needed refinement.
        Am J Orthod Dentofacial Orthop. 2018; 154: 47-54
        • Lombardo L.
        • Arreghini A.
        • Ramina F.
        • Huanca Ghislanzoni L.T.
        • Siciliani G.
        Predictability of orthodontic movement with orthodontic aligners: a retrospective study.
        Prog Orthod. 2017; 18: 35
        • Talaat S.
        • Kaboudan A.
        • Breuning H.
        • Ragy N.
        • Elshebiny T.
        • Kula K.
        • et al.
        Reliability of linear and angular dental measurements with the OrthoMechanics Sequential Analyzer.
        Am J Orthod Dentofacial Orthop. 2015; 147: 264-269
        • Kurth J.R.
        • Kokich V.G.
        Open gingival embrasures after orthodontic treatment in adults: prevalence and etiology.
        Am J Orthod Dentofacial Orthop. 2001; 120: 116-123
        • Hussels W.
        • Nanda R.S.
        Effect of maxillary incisor angulation and inclination on arch length.
        Am J Orthod Dentofacial Orthop. 1987; 91: 233-239