Journal of Prosthetic Dentistry
Research and Education| Volume 129, ISSUE 3, P486-494, March 2023

Effect of variations in facial flow curves on the perceptions of smile esthetics by laypeople


      Statement of problem

      Information about the effect of the facial flow concept on the smile esthetic perception of laypeople is lacking.


      The purpose of this study was to determine the effect of the facial flow concept on laypeople’s perception of smile esthetics.

      Material and methods

      Frontal full-face images of a female volunteer were digitally altered to create commissural line and transverse occlusal plane inclinations, a dental midline shift, and facial asymmetries. A questionnaire was developed, and a single researcher asked 400 evaluators to rate the attractiveness of the different smiles by using a visual analog scale. The subsequent data were analyzed by using 3-factor repeated measures ANOVA and post hoc Bonferroni tests.


      Images with commissural line and transverse occlusal plane inclinations pointing toward the green side of the facial flow curve were found to be more attractive than those with inclinations pointing to the red side (P<.001). Asymmetric facial images with the dental midline coinciding with the facial flow curve had higher esthetic scores than those without (P<.001). Images that showed parallelism between the transverse occlusal plane and commissural line inclinations were perceived as more esthetic (P<.001).


      In an asymmetric face model, the degree and direction of commissural line and transverse occlusal plane inclinations and dental midline shift influenced the perceived attractiveness of a smile.
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        • Silva B.P.
        • Jiménez-Castellanos E.
        • Martinez-de-Fuentes R.
        • Greenberg J.R.
        • Chu S.
        Laypersons’ perception of facial and dental asymmetries.
        Int J Periodontics Restorative Dent. 2013; 33: 162-171
        • Magne P.
        • Belser U.
        Bonded porcelain restorations in the anterior dentition: a biomimetic approach.
        1st ed. Quintessence, Chicago2002: 23-55
        • Ozdemir H.
        • Koseoglu M.
        Relationship between different points on the face and the width of maxillary central teeth in a Turkish population.
        J Prosthet Dent. 2019; 122: 63-68
        • Ozdemir H.
        • Koseoglu M.
        • Bayindir F.
        An investigation of the esthetic indicators of maxillary anterior teeth in young Turkish people.
        J Prosthet Dent. 2018; 120: 583-588
        • Koseoglu M.
        • Bayindir F.
        Effects of gingival margin asymmetries on the smile esthetic perception of dental professionals and laypeople.
        J Esthet Restor Dent. 2020; 32: 1-7
        • Koseoglu M.
        • Ozdemir H.
        • Bayindir F.
        Evaluation of different smile parameters in the Turkish population.
        Int Dent Res. 2018; 8: 1-6
        • Rigsbee O.H.
        • Sperry T.P.
        • BeGole E.A.
        The influence of facial animation on smile characteristics.
        Int J Adult Orthodon Orthognath Surg. 1988; 3: 233-239
        • Ackerman J.L.
        • Ackerman M.B.
        • Brensinger C.M.
        • Landis J.R.
        A morphometric analysis of the posed smile.
        Clin Orthod Res. 1998; 1: 2-11
        • Ritter D.E.
        • Gandini Jr., L.G.
        • Pinto Ados S.
        • Ravelli D.B.
        • Locks A.
        Analysis of the smile photograph.
        World J Orthod. 2006; 7: 279-285
        • Van Der Geld P.
        • Oosterveld P.
        • Bergé S.J.
        • Kuijpers-Jagtman A.M.
        Tooth display and lip position during spontaneous and posed smiling in adults.
        Acta Odontol Scand. 2008; 66: 207-213
        • Kim J.
        • Topolski R.
        • Dickinson D.
        The influence of lip form on incisal display with lips in repose on the esthetic preferences of dentists and laypeople.
        J Prosthet Dent. 2017; 118: 413-421
        • Al Taki A.
        • Khalesi M.
        • Shagmani M.
        • Yahia I.
        • Al Kaddah F.
        Perceptions of altered smile esthetics: a comparative evaluation in orthodontists, dentists, and laypersons.
        Int J Dent. 2016; 1: 1-11
        • Chiche G.J.
        • Pinault A.
        Esthetics of anterior fixed prosthodontics.
        Quintessence, Chicago1994: 13-30
        • Fradeani M.
        Esthetic rehabilitation in fixed prosthodontics.
        in: 1st ed. Esthetic analysis: a systematic approach to prosthetic treatment. vol. 1. Quintessence, Hanover Park2004: 35-61
        • Fradeani M.
        Evaluation of dentolabial parameters as part of a comprehensive esthetic analysis.
        Eur J Esthet Dent. 2006; 1: 62-69
        • Padwa B.L.
        • Kaiser M.O.
        • Kaban L.B.
        Occlusal cant in the frontal plane as a reflection of facial asymmetry.
        J Oral Maxillofac Surg. 1997; 55: 811-816
        • Gul-e-Erum
        • Fida M.
        Changes in smile parameters as perceived by orthodontists, dentists, artists, and laypeople.
        World J Orthod. 2008; 9: 132-140
        • Geron S.
        • Atalia W.
        Influence of sex on the perception of oral and smile esthetics with different gingival display and incisal plane inclination.
        Angle Orthod. 2008; 9: 132-140
      1. The glossary of prosthodontic terms: ninth edition.
        J Prosthet Dent. 2017; 117: 1-105
        • Lombardi R.E.
        The principles of visual perception and their clinical application to denture esthetics.
        J Prosthet Dent. 1973; 29: 358-382
        • Zarb G.A.
        • Hobkirk J.
        • Eckert S.
        • Jacob R.
        Prosthodontic treatment for edentulous patients.
        13th ed. Mosby/Elsevier, St. Louis2012: 309-310
        • Latta Jr., G.H.
        The midline and its relation to the anatomic landmarks in the edentulous patient.
        J Prosthet Dent. 1988; 59: 681-683
        • Silva B.P.
        • Jiménez-Castellanos E.
        • Martinez-de-Fuentes R.
        • Fernandez A.A.
        • Chu S.
        Perception of maxillary dental midline shift in asymmetric faces.
        Int J Esthet Dent. 2015; 10: 588-596
        • Cardash H.S.
        • Ormanier Z.
        • Laufer B.Z.
        Observable deviation of the facial and anterior tooth midlines.
        J Prosthet Dent. 2003; 89: 282-285
        • Beyer J.W.
        • Lindauer S.J.
        Evaluation of dental midline position.
        Semin Orthod. 1998; 4: 145-152
        • Johnston C.D.
        • Burden D.J.
        • Stevenson M.R.
        The influence of dental to facial midline discrepancies on dental attractiveness ratings.
        Eur J Orthod. 1999; 21: 517-522
        • Ker A.J.
        • Chan R.
        • Fields H.W.
        • Beck M.
        • Rosenstiel S.
        Esthetics and smile characteristics from the layperson’s perspective: a computer-based survey study.
        J Am Dent Assoc. 2008; 139: 1318-1327
        • Pinho S.
        • Ciriaco C.
        • Faber J.
        • Lenza M.
        Impact of dental asymmetries on the perception of smile esthetics.
        Am J Orthod Dentofacial Orthop. 2007; 132: 748-753
        • Rodrigues C.D.
        • Magnani R.
        • Machado M.S.
        • Oliveira O.B.
        The perception of smile attractiveness.
        Angle Orthod. 2009; 79: 634-639
        • Bidra A.
        • Uribe F.
        • Taylor T.D.
        • Agar J.R.
        • Rungruanganunt P.
        • Neace W.P.
        The relationship of facial anatomic landmarks with midlines of the face and mouth.
        J Prosthet Dent. 2009; 102: 94-103
        • Silva B.P.
        • Mahn E.
        • Stanley K.
        • Coachman C.
        The facial flow concept: an organic orofacial analysis—the vertical component.
        J Prosthet Dent. 2019; 121: 189-194
        • Silva B.P.
        • Jimenez-Castellanos E.
        • Finkel S.
        • Macias I.R.
        • Chu S.
        Layperson's preference regarding orientation of the transverse occlusal plane and commissure line from the frontal perspective.
        J Prosthet Dent. 2017; 117: 513-516
        • Silva B.P.
        • Jiménez-Castellanos E.
        • Stanley K.
        • Mahn E.
        • Coachman C.
        • Finkel S.
        Layperson's perception of axial midline angulation in asymmetric faces.
        J Esthet Restor Dent. 2018; 30: 119-125
        • Pinzan Vercelino C.R.M.
        • Costa A.C.S.
        • Ferreira M.C.
        • Bramante F.S.
        • Fialho M.P.N.
        • de Araújo Gurgel J.
        Comparison of gingival display in smile attractiveness among restorative dentists, orthodontists, prosthodontists, periodontists, and laypeople.
        J Prosthet Dent. 2020; 123: 314-321
        • Correa B.D.
        • Bittencourt M.A.V.
        • Machado A.W.
        Influence of maxillary canine gingival margin asymmetries on the perception of smile esthetics among orthodontists and laypersons.
        Am J Orthod Dentofacial Orthop. 2014; 145: 55-63
        • Coachman C.
        • Calamita M.A.
        • Sesma N.
        Dynamic documentation of the smile and the 2D/3D digital smile design process.
        Int J Periodontics Restorative Dent. 2017; 37: 183-193
        • Magne P.
        • Salem P.
        • Magne M.
        Influence of symmetry and balance on visual perception of a white female smile.
        J Prosthet Dent. 2018; 120: 573-582
        • Machado A.W.
        • McComb R.W.
        • Moon W.
        • Gandini Jr., L.G.
        Influence of the vertical position of maxillary central incisors on the perception of smile esthetics among orthodontists and laypersons.
        J Esthet Restor Dent. 2013; 25: 392-401
        • Kokich V.O.
        • Kokich V.G.
        • Kiyak H.A.
        Perceptions of dental professionals and laypersons to altered dental esthetics: asymmetric and symmetric situations.
        Am J Orthod Dentofacial Orthop. 2006; 130: 141-151
        • Witt M.
        • Flores-Mir C.
        Laypeople’s preferences regarding frontal dentofacial esthetics: tooth-related factors.
        J Am Dent Assoc. 2011; 142: 635-645