Korean J Orthod.  2025 Jan;55(1):48-57. 10.4041/kjod24.152.

The effects of maxillary incisor positions and chin prominences on the perception of lateral smiling profile attractiveness among orthodontists and laypersons

• Yongwongsoontorn P
• Kanpittaya P

• KMID: 2565028
• DOI: http://doi.org/10.4041/kjod24.152

Abstract

Objective
To evaluate the ideal anteroposterior position of incisors in lateral smiling profiles with different chin prominences and to relate these positions to nose and chin landmarks based on the perceptions of orthodontists and laypersons.
Methods
A lateral smiling profile image of a female subject was adjusted to create five levels of chin prominence (–6, –3, 0, +3, +6 mm). For each level, the anteroposterior positions of the maxillary incisors were adjusted across five positions (–4, –2, 0, +2, +4 mm). Thirty-six orthodontists and 36 laypersons rated the attractiveness of each profile using a visual analog scale. The maxillary incisor position (U1) was measured relative to the external nose and chin landmarks (E-lines). Differences in perceptions between orthodontists and laypersons were analyzed.
Results
For profiles with 6 and 3 mm chin retrusion, the most favored incisor positions were the 2 mm retrusion and unaltered positions, respectively. For the unaltered chin prominence, orthodontists preferred unaltered incisors, while laypersons favored 2 mm protrusion. Conversely, for 3 and 6 mm chin protrusion, both groups preferred 4 and 2 mm protrusion, respectively. The distance between U1 and the E-line is the most attractive images ranged from 8.5 to 11.5 mm. Based on the regression model, an optimal U1-E-line distance of 8.95 mm was recommended.
Conclusions
The preferred incisor position is influenced by chin prominence, with the incisor position shifting in the same direction as the chin. The U1 E-line can be a useful clinical tool for determining the proper incisor positioning. Esthetic perceptions were generally consistent between orthodontists and laypersons.

Keyword

Esthetics; Perception; Soft tissue

Figure

• 

  Figure 1 The original smiling image of the subject.

• 

  Figure 2 The 25 final images after the adjustment of chin protrusion and incisor positions.

• 

  Figure 3 The attractiveness score (median). A, Orthodontists; B, Laypersons.

• 

  Figure 4 Differences of attractiveness score, median (standard deviation), between 5 incisor positions within 5 series of chin prominences using Kruskal–Wallis and post-hoc analyses. A, The most attractive image in 6 mm chin retrusion was 2 mm incisor retrusion for both groups. B, The most attractive image in 3 mm chin retrusion was unaltered incisor position for both groups. C, The most attractive image in unaltered chin prominence were unaltered incisor position (for orthodontists) and 2 mm incisor protrusion (for laypersons). D, The most attractive image in 3 mm chin protrusion was 4 mm incisor protrusion for both groups. E, The most attractive image in 6 mm chin protrusion was 2 mm incisor protrusion for both groups.

Reference

References

1. Proffit WR. 2000; The soft tissue paradigm in orthodontic diagnosis and treatment planning: a new view for a new century. J Esthet Dent. 12:46–9. https://pubmed.ncbi.nlm.nih.gov/11323833/. DOI: 10.1111/j.1708-8240.2000.tb00198.x.

2. Andrews LF, Andrews WA. 2001. Syllabus of the Andrews orthodontic philosophy. 9th ed. Lawrence F;San Diego: https://www.scirp.org/reference/referencespapers?referenceid=2606556. DOI: 10.12987/9780300172591-003.

3. Andrews WA. 2008; AP relationship of the maxillary central incisors to the forehead in adult white females. Angle Orthod. 78:662–9. https://doi.org/10.2319/0003-3219(2008)078[0662:Arotmc]2.0.Co;2. DOI: 10.2319/0003-3219(2008)078[0662:AROTMC]2.0.CO;2. PMID: 18302465.

4. Gidaly MP, Tremont T, Lin CP, Kau CH, Souccar NM. 2019; Optimal antero-posterior position of the maxillary central incisors and its relationship to the forehead in adult African American females. Angle Orthod. 89:123–8. https://doi.org/10.2319/120517-833.1. DOI: 10.2319/120517-833.1. PMID: 30183324. PMCID: PMC6637935.

5. Cho SW, Byun SH, Yi S, Jang WS, Kim JC, Park IY, et al. 2021; Sagittal relationship between the maxillary central incisors and the forehead in digital twins of Korean adult females. J Pers Med. 11:203. https://doi.org/10.3390/jpm11030203. DOI: 10.3390/jpm11030203. PMID: 33805617. PMCID: PMC8001265.

6. Schlosser JB, Preston CB, Lampasso J. 2005; The effects of computer-aided anteroposterior maxillary incisor movement on ratings of facial attractiveness. Am J Orthod Dentofacial Orthop. 127:17–24. https://doi.org/10.1016/j.ajodo.2003.11.025. DOI: 10.1016/j.ajodo.2003.11.025. PMID: 15643410.

7. Ricketts RM. 1960; A foundation for cephalometric communication. Am J Orthodontics. 46:330–57. https://doi.org/10.1016/0002-9416(60)90047-6. DOI: 10.1016/0002-9416(60)90047-6.

8. Torsello F, Graci M, Grande NM, Deli R. 2010; Relationships between facial features in the perception of profile attractiveness. Prog Orthod. 11:92–7. https://doi.org/10.1016/j.pio.2010.04.002. DOI: 10.1016/j.pio.2010.04.002. PMID: 20974445.

9. Czarnecki ST, Nanda RS, Currier GF. 1993; Perceptions of a balanced facial profile. Am J Orthod Dentofacial Orthop. 104:180–7. https://doi.org/10.1016/s0889-5406(05)81008-x. DOI: 10.1016/S0889-5406(05)81008-X. PMID: 8338071.

10. Murakami T, Kataoka T, Tagawa J, Yamashiro T, Kamioka H. 2016; Antero-posterior and vertical facial type variations influence the aesthetic preference of the antero-posterior lip positions. Eur J Orthod. 38:414–21. https://doi.org/10.1093/ejo/cjv073. DOI: 10.1093/ejo/cjv073. PMID: 26453593.

11. Ioi H, Nakata S, Nakasima A, Counts A. 2005; Effect of facial convexity on antero-posterior lip positions of the most favored Japanese facial profiles. Angle Orthod. 75:326–32. https://pubmed.ncbi.nlm.nih.gov/15898368/.

12. Abu Arqoub SH, Al-Khateeb SN. 2011; Perception of facial profile attractiveness of different antero-posterior and vertical proportions. Eur J Orthod. 33:103–11. https://doi.org/10.1093/ejo/cjq028. DOI: 10.1093/ejo/cjq028. PMID: 20558590.

13. Naini FB, Donaldson AN, McDonald F, Cobourne MT. 2012; Assessing the influence of lower facial profile convexity on perceived attractiveness in the orthognathic patient, clinician, and layperson. Oral Surg Oral Med Oral Pathol Oral Radiol. 114:303–11. https://doi.org/10.1016/j.tripleo.2011.07.031. DOI: 10.1016/j.tripleo.2011.07.031. PMID: 22883980.

14. Ioi H, Nakata S, Nakasima A, Counts AL. 2005; Anteroposterior lip positions of the most-favored Japanese facial profiles. Am J Orthod Dentofacial Orthop. 128:206–11. https://doi.org/10.1016/j.ajodo.2004.04.030. DOI: 10.1016/j.ajodo.2004.04.030. PMID: 16102406.

15. Modarai F, Donaldson JC, Naini FB. 2013; The influence of lower lip position on the perceived attractiveness of chin prominence. Angle Orthod. 83:795–800. https://doi.org/10.2319/122912-974.1. DOI: 10.2319/122912-974.1. PMID: 23530543. PMCID: PMC8744523.

16. Coleman GG, Lindauer SJ, Tüfekçi E, Shroff B, Best AM. 2007; Influence of chin prominence on esthetic lip profile preferences. Am J Orthod Dentofacial Orthop. 132:36–42. https://doi.org/10.1016/j.ajodo.2005.07.025. DOI: 10.1016/j.ajodo.2005.07.025. PMID: 17628248.

17. Sutthiprapaporn P, Manosudprasit A, Pisek A, Manosudprasit M, Pisek P, Phaoseree N, et al. 2020; Establishing esthetic lateral cephalometric values for Thai adults after orthodontic treatment. Khon Kaen Uni Dent J. 23:31–41. https://he01.tci-thaijo.org/index.php/KDJ/article/view/241633.

18. Arnett GW, Jelic JS, Kim J, Cummings DR, Beress A, Worley CM, et al. 1999; Soft tissue cephalometric analysis: diagnosis and treatment planning of dentofacial deformity. Am J Orthod Dentofacial Orthop. 116:239–53. https://doi.org/10.1016/s0889-5406(99)70234-9. DOI: 10.1016/S0889-5406(99)70234-9. PMID: 10474095.

19. Sorathesn K. 1988; Craniofacial norm for Thai in combined orthodontic surgical procedure. J Dent Assoc Thai. 38:190–201. Thai.

20. Ahn HW, Chang YJ, Kim KA, Joo SH, Park YG, Park KH. 2014; Measurement of three-dimensional perioral soft tissue changes in dentoalveolar protrusion patients after orthodontic treatment using a structured light scanner. Angle Orthod. 84:795–802. https://doi.org/10.2319/112913-877.1. DOI: 10.2319/112913-877.1. PMID: 24611593. PMCID: PMC8641284.

21. Cicchetti DV. 1994; Guidelines, criteria, and rules of thumb for evaluating normed and standardized assessment instruments in psychology. Psychol Assess. 6:284–90. https://doi.org/10.1037/1040-3590.6.4.284. DOI: 10.1037/1040-3590.6.4.284.

22. Cao L, Zhang K, Bai D, Jing Y, Tian Y, Guo Y. 2011; Effect of maxillary incisor labiolingual inclination and anteroposterior position on smiling profile esthetics. Angle Orthod. 81:121–29. https://doi.org/10.2319/033110-181.1. DOI: 10.2319/033110-181.1. PMID: 20936964. PMCID: PMC8926362.

23. Agostino P, Butti AC, Poggio CE, Salvato A. 2007; Perception of the maxillary incisor position with respect to the protrusion of nose and chin. Prog Orthod. 8:230–9. https://pubmed.ncbi.nlm.nih.gov/18030369/.

24. He D, Gu Y, Sun Y. 2019; Evaluation of aesthetic anteroposterior position of maxillary incisors in patients with extraction treatment using facial reference lines. J Int Med Res. 47:2951–60. https://doi.org/10.1177/0300060519850740. DOI: 10.1177/0300060519850740. PMID: 31144551. PMCID: PMC6683892. PMID: 05e6c19bd4454c7c84253c6bf6b217d5.

25. Prengsukarn N, Chintavalakorn R, Mitrirattanakul S, Saengfai NN. 2021; Comparative assessment of maxillary central incisor position in Thai females with facial harmony vs. pre-orthodontic treatment. Khon Kaen Uni Dent J. 24:92–100. https://he01.tci-thaijo.org/index.php/KDJ/article/view/245979.

26. Holdaway RA. 1983; A soft-tissue cephalometric analysis and its use in orthodontic treatment planning. Part I. Am J Orthod. 84:1–28. https://doi.org/10.1016/0002-9416(83)90144-6. DOI: 10.1016/0002-9416(83)90144-6. PMID: 6575614.

27. Ghaleb N, Bouserhal J, Bassil-Nassif N. 2011; Aesthetic evaluation of profile incisor inclination. Eur J Orthod. 33:228–35. https://doi.org/10.1093/ejo/cjq059. DOI: 10.1093/ejo/cjq059. PMID: 20716642.

28. Zarif Najafi H, Oshagh M, Khalili MH, Torkan S. 2015; Esthetic evaluation of incisor inclination in smiling profiles with respect to mandibular position. Am J Orthod Dentofacial Orthop. 148:387–95. https://doi.org/10.1016/j.ajodo.2015.05.016. DOI: 10.1016/j.ajodo.2015.05.016. PMID: 26321336.