ORIGINAL ARTICLE
Differences in facial profile and dental esthetic perceptions between young adults and orthodontists Lu Yin,a Mingchun Jiang,b Wenjing Chen,c Roger J. Smales,d Qingzhu Wang,e and Lei Tangf Nanjing, People's Republic of China, and Adelaide, Australia
Introduction: The principal aim of this study was to investigate differences in perception of soft-tissue facial profiles and dental esthetics between young Chinese adults and orthodontists. Methods: Eight hundred ninety-two subjects (444 male, 448 female), ages 16 to 24 years, chose 1 image from among 5 profile silhouettes and from among 10 ranked color photographs of the aesthetic component (AC) of the index of orthodontic treatment need that most closely resembled their own profile and dental esthetic appearance, respectively. A panel of 20 orthodontists then independently repeated the same image selection process. Each subject also completed the Eysenck personality questionnaire for psychoticism. We used the MannWhitney U test and the Spearman rank correlation test, with statistical significance set at a 5 0.05. Results: Only 37.0% of subjects had straight profiles by objective orthodontic assessment, but 85.0% chose straight profiles by subjective self-perception. About 17.5%, mainly females, chose the mild convex as the ideal profile. Only 2.5% of the subjects were ranked 1 on the AC by orthodontists, but 43.6% chose 1, or ideal, by self-perception. Male subjects scored significantly higher than did female subjects for self-perceived facial profiles (more protruded chins) and for the AC (more attractive dental appearance). Subjects with high psychoticism T scores (.50) scored significantly lower for self-perceived facial profiles (more retruded chins) and on the AC (less attractive dental appearance). Conclusions: Young Chinese adults perceived their facial profiles and dental appearances to be significantly more straight and attractive, respectively, than did the orthodontists. A significant proportion of the young adults, mainly women, preferred a mild convex facial profile. High psychoticism scores might significantly affect the self-perception of orthodontic treatment needs. (Am J Orthod Dentofacial Orthop 2014;145:750-6)
a Associate clinical professor, Hospital of Nanjing Army Command College, Nanjing, People's Republic of China. b Associate professor and department chair, Hospital of Nanjing Army Command College, Nanjing, People's Republic of China. c Professor and department chair, Department of Orthodontics, College of Stomatology, Nanjing Medical University, Nanjing, People's Republic of China. d Visiting research fellow, School of Dentistry, Faculty of Health Sciences, University of Adelaide, Adelaide, Australia. e Lecturer, Department of Orthodontics, College of Stomatology, Nanjing Medical University, Nanjing, People's Republic of China. f Lecturer, Research Center, Nanjing Army Command College, Nanjing, People's Republic of China. All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported. Supported by the Natural Science Foundation of Jiangsu Province (grant number BK2012528), the Foundation of Health Bureau in Jiangsu Province (grant number Z201212), and the Priority Academic Program Development of Jiangsu Higher Education Institutions. Address correspondence to: Wenjing Chen, Department of Orthodontics, College of Stomatology, Nanjing Medical University, Nanjing 210029, PR China; e-mail, [email protected]. Submitted, June 2013; revised and accepted, January 2014. 0889-5406/$36.00 Copyright Ó 2014 by the American Association of Orthodontists. http://dx.doi.org/10.1016/j.ajodo.2014.01.021
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sthetics is a key motivational reason for patients seeking orthodontic treatment.1,2 The perceptions of facial profile and dental esthetics are essentially based on how subjects evaluate themselves.3 However, people vary in their emotions, thinking, and behavior, and these differences create individualism.4 Perceptions of esthetics also differ between laypersons and orthodontists.5-9 The professional opinions of orthodontists regarding dentofacial esthetics are made more objective by guidelines, norms, and ideal ratios and angles. But the perceptions of laypersons are largely motivated by subjective feelings such as the “beauty culture” in their peer groups and social norms in general.10,11 Some studies have found obvious differences in perceptions among groups of laypersons, dental students, and orthodontists.12,13 During postpuberty and early adulthood, young adults are an integral part of orthodontic patients. During the period of transition from adolescence to adulthood, young adults possess the typical age characteristics for their psychological behavior.14 The most
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Table I. Distribution by subjects' sex, geographic region of high schools attended, and age Geographic region of the subjects' high schools (n)
Male (444) Female (448) Total (892)
Extra-large and large cities 167 157 324
Medium cities 147 151 298
Small cities and rural areas 130 140 270
Age (y) Mean (SD) 18.74 (1.51) 19.03 (1.64) 18.81 (1.57)
Minimum 16 16 16
Maximum 23 24 24
the personality traits of young adults and their potential perceptions of facial profiles and dental esthetics. Therefore, in this study, we aimed to investigate the self-perceptions of facial profiles and dental esthetics among young adults, and to evaluate differences between self-perceptions and orthodontists' assessments. We also examined whether the sex and personality traits of young adults might affect their esthetic perceptions. The null hypothesis was that in a selected group of young Chinese adults assessing their soft-tissue facial profiles and dental esthetics, there are no significant differences between their self-assessments and those of orthodontists, and that the self-assessments are not significantly affected by personality traits. MATERIAL AND METHODS
Fig 1. Original male (left) and female (right) straight profile images.
central concept in personality psychology is the trait, which can be used to predict and explain a significant fraction of a subject's behavior. Eysenck claimed that personality could be described based on 3 fundamental dimensions or traits.15 Psychoticism, 1 of these traits, subsumed a variety of habitual behaviors: eg, aggressive, egocentric, creative, impulsive, and lacking empathy. Because patients who receive orthodontic treatment need to gain satisfaction from improving their esthetics, the self-perceptions of young adults are important indicators when deciding to undertake treatment, and this might complement conventional clinical evaluation. Although some authors have concluded that the professional opinions of orthodontists are generally more critical than those of laypersons when assessing dentofacial esthetics, few authors have investigated the selfperceptions of facial profiles and dental esthetics among young adults.16-19 Some studies have found that psychological factors do have certain effects on the perception of facial profile and dental esthetics.20,21 But few studies have investigated the relationship between
Students from 3 Chinese universities attended general health and oral health examinations at the Hospital of Nanjing Army Command College in 2011. Three universities were randomly selected from the 9 universities in the Pukou district in Nanjing, and the university classes were also randomly chosen. A total of 892 subjects gave their approval to participate in the study. Distributions by sex, geographic regions of the high schools attended, and ages are shown in Table I. Students were excluded if they had a history of orthodontic treatment or facial surgery, or a background of stomatology education. The study was approved by the ethics institutional review board of the Hospital of Nanjing Army Command College. All students received written information about the aims and procedures of the research and were told that participation was voluntary. Soft-tissue facial profiles can be assessed by means of standardized silhouettes and photographs.22-24 However, to reduce subjectivity, facial silhouettes rather than facial profile photographs were viewed by the subjects when scoring their facial profiles.25,26 According to selected landmarks, based on currently accepted criteria of softtissue measurements, representative straight-profile silhouettes of male and female subjects (Fig 1) were first drawn using Photoshop (CS 8.0.1; Adobe Systems, San Jose, Calif).22,27,28 A straight profile is generally considered to be the ideal for facial esthetics. Based on 2 straight profile silhouettes for males and females, an
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Fig 2. Pogonion manipulations of the female (upper) and the male (lower) straight facial profile images. From left to right, image 1 (protruded 12 ), image 2 (protruded 6 ), image 3 (straight), image 4 (retruded 6 ), and image 5 (retruded 12 ).
additional series of profile silhouettes was then generated by altering the original position of pogonion, which was protruded and then retruded by 6 and 12 from the straight profiles. The changes were artistically modified to maintain soft-tissue continuity and sex distinctions. The manipulated silhouettes formed 2 sets of male and female profile images. The scores for the profiles were the following: 1, severe concave; 2, mild concave; 3, straight; 4, mild convex; and 5, severe convex (Fig 2). The aesthetic component (AC) of the index of orthodontic treatment need is one dental appearance scale used to measure perceptions of dental esthetics.29 The AC consists of a scale of 10 color photographs showing different levels of dental attractiveness: 1 represents the most attractive, and 10 the least attractive arrangement of teeth in the AC, where 1 is identified with the ideal for dental esthetics. Personality trait theorists have developed many questionnaires to assess personality.4 The Eysenck personality questionnaire, which is highly reliable with strong evidence of validity, is one of the best-known and the most widely used for personality assessment in China.30 A psychologist (MC.J.) assessed all subjects and then changed the raw scores into standard T scores.
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The specially designed questionnaire comprised 4 sections: (1) sociodemographic information, (2) male and female images of facial profiles, (3) the AC, and (4) the Eysenck personality questionnaire. The first section of the questionnaire focused on the subjects' sociodemographic data: sex, birth date, family income, and level of education. The image-based questionnaire of facial profile had 2 parts: “Select the image that you think has the most attractive facial profile” and “Select the image that you think most closely represents your facial profile.” The subjects were asked to use numbers 1 to 5 to select the images from the relevant profile silhouettes of the sexes. The AC also had 2 parts: “Select the image that you think has the most attractive teeth” and “Select the image that you think most closely represents your teeth.” The subjects were asked to use numbers 1 to 10 to select images from the AC. The Eysenck personality questionnaire was the last section. The subjects were given 20 minutes to complete anonymously the questionnaires, which were marked by numeric codes. For each subject, we used a digital camera (EOS Rebel-D; Canon, Tokyo, Japan) to obtain 2 photographs of the right facial profile and frontal view of the teeth.
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Table II. Distribution by judges' sex, age, and specialty
experience n
Specialty Age (y) experience (y) Male Female Mean (SD) Mean (SD) Professors 1 1 46.75 (4.35) 23.00 (4.69) Associate professors 1 1 Associate clinical 3 3 33.67 (4.50) 11.83 (4.36) professors Graduate students 4 6 25.4 (1.43) 3.56 (1.33) Total 9 11 32.15 (8.88) 10.05 (8.15)
The subjects' photographs were marked with the same numeric codes as the questionnaires. A professional panel of orthodontists was selected to assess the subjects' photographs. This panel consisted of 20 orthodontists who practiced in the orthodontic departments at the Affiliated Hospital of Stomatology of Nanjing Medical University and the Hospital of Nanjing Army Command College. Their demographic information is included in Table II. The 2 professors instructed the other orthodontists in the evaluation of the softtissue facial profiles and the application of the AC over 2 weeks before this study started. Using the 2 sets of manipulated facial profile silhouettes and the AC, the professional panel scored the subjects' facial profiles and dental esthetics. The mean scores of the panel were increased or decreased to the nearest whole number before being analyzed. Statistical analysis
All scores were entered into the SPSS statistical software package (version 13.0; SPSS, Chicago, Ill). Data distributions were presented as means and standard deviations and were analyzed using the nonparametric Mann-Whitney U test and the Spearman rank correlation test. The probability level for statistical significance was set at a 5 0.05. The scores for 50 subjects were repeated by the same panel after a 2-week interval. The panel's kappa scores were 0.92 for the facial profiles and 0.86 for dental esthetics, indicating good agreement.
significant proportion (17.5%) of subjects also selected the mild convex profile as ideal. Table IV shows the distribution of the AC results, which were also significantly different between the subjects and the orthodontists (P \0.001). Most of the orthodontists' assessments were scores 3, 4, and 5 (22.1%, 21.1%, and 23.1%, respectively); this contrasted with the subjects’ own perceived dental esthetic assessments, where most photographic image scores were 1, 2, and 3 (43.6%, 27.5%, and 20.1%, respectively). The subjects' perceived mean AC score (2.15 6 1.65) was significantly more favorable than the orthodontists' mean AC score (4.03 6 1.64). Not surprisingly, most subjects selected score 1 (88.8%) as the ideal perceived dental appearance, with no scores greater than 4 selected. Table V shows that there were significant differences between the male and female subjects when comparing the differences in scores between the orthodontists and the subjects. Male subjects had greater differences than did female subjects for their own perceived facial profiles (more protruded chins) and dental esthetics (more attractive), but fewer differences than female subjects for the perceived ideal facial profile and ideal dental appearance. Apart from 1 instance (P 5 0.97), significant differences were also present between the low and high T scores for psychoticism when comparing the differences between the orthodontists and the subjects. (The T scores were \50 for 692 subjects and .50 for 200 subjects.) Subjects with T scores greater than 50 had fewer differences than did those with scores less than 50 for their own perceived facial profiles (less protruded chins) and dental esthetics (less attractive), and also fewer differences than those with scores less than 50 for the perceived ideal facial profile. There were no significant differences between subjects with high and low T scores for their perceived ideal dental esthetics. Table VI shows that with 1 exception, for psychoticism (P 5 0.71), both sex and psychoticism were significantly and negatively correlated with the differences in scores between the orthodontists and the subjects for facial profiles and dental esthetics (AC). However, the Spearman rank correlation values were low. To some extent, sex and psychoticism results mirrored each other.
RESULTS
Table III shows the distribution of the facial profile results, which were significantly different between the subjects and the orthodontists (P \0.0001). Although the assessments by the orthodontists (37%) and the subjects (85%) favored the straight profile (score 3), these assessments were heavily skewed by the subjects who closely equated their own perceived facial profiles with the perceived ideal facial profile (78.5%). However, a
DISCUSSION
Only 37.0% of the subjects had straight facial profiles by the more objective orthodontic assessments, but 85.0% chose straight profiles by subjective selfperceptions (Table III). The results suggest that the young adults' subjective perceptions of their profiles are inaccurate; this is not surprising, since people cannot directly obtain visual information of their profiles by looking at
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Table III. Observations from facial silhouettes Profile Silhouettes Assessment 1 OAP 46 (5.2%) SAP 4 (0.4%) c2 5 466.5; df 5 4; P \0.0001 SIP 2 (0.2%)
2 188 (21.1%) 34 (3.8%)
3 330 (37.0%) 758 (85.0%)
4 254 (28.5%) 90 (10.1%)
5 74 (8.3%) 6 (0.7%)
AC mean (SD)* 3.14 (1.00) 3.07 (0.42)
18 (2.0%)
700 (78.5%)
156 (17.5%)
16 (1.8%)
3.19 (0.49)
OAP, Orthodontist assessment of profile; SAP, subject assessment of profile; SIP, subject ideal assessment of profile. *Mean (SD) score for ranking of profile images.
Table IV. Observations from a set of 10 photographs in the AC Aesthetic Component Assessment 1 2 3 4 5 6 7 8 9 10 AC mean (SD)* OAAC 22 (2.5%) 149 (16.7%) 197 (22.1%) 188 (21.1%) 206 (23.1%) 48 (5.4%) 52 (5.8%) 26 (2.9%) 3 (3%) 1 (1%) 4.03 (1.64) SAAC 389 (43.6%) 245 (27.5%) 179 (20.1%) 31 (3.8%) 5 (6.0%) 8 (9.0%) 8 (9.0%) 15 (1.7%) 8 (9%) 4 (4%) 2.15 (1.65) c2 5 1798; df 5 18; P \0.001 SIAC 792 (88.8%) 52 (5.8%) 31 (3.8%) 17 (1.9%) 0 0 0 0 0 0 1.20 (0.67) OAAC, Orthodontist assessment of AC; SAAC, subject assessment of AC; SIAC, subject ideal assessment of AC. *Mean (SD) score for ranking of photographs.
Table V. Comparison of mean (SD) scores, from differences in assessments of facial profile and of AC, between sex and psychoticism Sex Assessment OAP-SAP OAAC-SAAC SIP-OIP SIAC-OIAC
Sex M F M F M F M F
Mean (SD) 0.11 (1.04) 0.37 (1.22) 1.99 (1.85) 0.74 (2.33) 0.16 (0.48) 0.50 (0.56) 0.09 (0.46) 1.26 (1.24)
Psychotiscism Z score 2.167
P value 0.03*
3.158
0.002y
4.510
0.000z
7.168
0.000z
Ps \50 .50 \50 .50 \50 .50 \50 .50
Mean (SD) 0.13 (1.08) 0.15 (0.97) 2.06 (1.69) 1.22 (2.51) 0.14 (0.45) 0.33 (0.59) 0.21 (0.69) 0.18 (0.58)
Z score 2.566
P value 0.01y
2.321
0.02*
3.007
0.003y
0.040
0.97
Statistical significance: *P \0.05; yP \0.01; zP \0.001. Ps, Psychoticsm; M, male; F, female; OAP, orthodontist assessment of profile; SAP, subject assessment of profile; OAAC, orthodontist assessment of the AC; SAAC, subject assessment of the AC; SIP, subject ideal profile; OIP, orthodontist ideal profile (5 3); SIAC, subject ideal AC; OIAC, orthodontist ideal AC (5 1).
a mirror. According to the theory of Gestalt psychology, the canonic perspective of the face is generally obtained from the frontal view rather than from less-informative perspectives such as profile or bird's-eye views. Some 78.5% of the subjects chose the straight profile, and 17.5% chose the mild convex profile as the ideal facial profile (Table III). Orthodontists, whose concepts of profile esthetics are influenced by their specialist training, prefer to use cephalometric measurements to assess facial profiles. Their treatment plans and outcomes are often devised to meet the more objective standards of orthodontic parameters and norms that reflect only the viewpoints of professionals, and which were generated in Western countries. However, according to
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cognitive dissonance theory, laypersons' perceptions of facial profiles are adopted from the social norms and “beauty culture” in their peer groups and society in general. Furthermore, social norms and “beauty culture” change with time and the effects of mass media, culture, race, and place. Therefore, the norms of the young adults' peer groups and society, and not the orthodontic norms, are the most important factors in facial-profile perceptions. Hence, a significant proportion of young Chinese adults preferred a mild convex facial profile rather than a straight profile. The results of the AC rankings show that the subjects rated their dental appearance significantly more favorably than did the orthodontists (Table IV). It would
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Table VI. Correlations (rs) between differences in as-
sessments and sex scores, and between differences in assessments and psychoticism scores Correlation and P value Sex (male/female) Psychoticism rs 0.103 0.097 P value 0.03* 0.04* OAAC-SAAC rs 0.222 0.182 0.009y P value 0.001z SIP-OIP rs 0.214 0.134 P value 0.000z 0.004y SIAC-OIAC rs 0.503 0.027 P value 0.000z 0.71 Assessment OAP-SAP
Statistical significance: *P \0.05; yP \0.01; zP \0.001. OAP, Orthodontist assessment of profile; SAP, subject assessment of profile; OAAC, orthodontist assessment of the AC; SAAC, subject assessment of the AC; SIP, subject ideal profile; OIP, orthodontist ideal profile (5 3); SIAC, subject ideal AC; OIAC, orthodontist ideal AC (5 1).
appear that the young adults were not unduly concerned about minor dental irregularities adversely affecting their appearance. It is not uncommon to observe that some patients with severe malocclusions are satisfied with or indifferent to their dental esthetics, whereas others are concerned about minor irregularities. In many patients, the principal motive for orthodontic treatment is the improvement of physical attractiveness, regardless of the functional severity of the deformity. Young adults, who lack professional orthodontic knowledge, might perceive their dental esthetics inaccurately. Therefore, orthodontists should discuss with their patients such possible misconceptions. Although most (88.8%) of the subjects preferred image 1 as the ideal dental appearance, some subjects preferred images 2, 3, and 4 for the AC (Table IV). Disability and disease do not always negatively affect subjective perceptions of well-being; even when they do, their impact depends on the person's expectations and preferences; on material, social, and psychological resources; and, more importantly, on socially and culturally derived values.31 Today, many close friendships and valued acquaintanceships involve young adults who first met by instant Internet messages, e-mails, chat rooms, and blogs. One survey of instant messaging indicated that during the early stages of interpersonal perception and selection, age, nickname, and self-explanation were the most important reasons for choosing a friend, rather than facial features, blood type, and occupation.32 Thus, in cyberspace, where important visual and auditory information might be absent, young Chinese adults display higher-than-expected individualism and egocentric tendencies. Hence, dental irregularities
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have little significance here when making new friends. Therefore, when an orthodontist plans to improve a patient's dental appearance, it is important first to know whether the orthodontist's ideal concept of esthetics will coincide with that of the patient. There were significant differences between the male and female subjects in their self-perceptions of facial profiles and dental esthetics (Table V). A straight profile was preferred by the male subjects, and a mild convex profile was preferred by the female subjects. People who subscribe to traditional sex stereotypes tend to assume that women with a mild convex profile are more beautiful, kind, naïve, and weak, and less socially dominant. By contrast, people tend to see men as more firm, alert, strong, and coordinated. Many studies have suggested that masculinity and femininity are significantly shaped by culture.33,34 Findings from the AC scores suggest that male subjects are more tolerant of less favorable dental esthetics than are female subjects, and that females are more critical in their perceptions of adverse impacts related to dental esthetics (Table V). Psychosocial research shows that males and females, even in early infancy, behave differently.35,36 Women tend to “internalize” their discomfort; they dwell mentally on their distress and seek causes within themselves. By contrast, men more often “externalize” their discomfort; they tend to look for causes outside themselves. Perhaps this is one of the reasons that females expressed greater awareness of facial profile and dental attractiveness than did males. In accordance with recent professional guidelines,37 orthodontists must realize how greatly their own assessments can differ from those of their patients regarding ideal facial profiles and dental appearances. Subjects who had high psychoticism scores (.50) perceived that they had a more mild convex (retruded chin) facial profile, and that the ideal facial profile was more convex than was perceived by subjects with low psychoticism scores (\50) (Table V). Personality traits appear to have some effect on facial profile perceptions. A common bias is that we tend to see a “strong” jaw as a sign of a firm and aggressive character. By contrast, a person with a “weak” jaw is seen as emotional and kind. Psychological studies suggest that people instinctively respond to an infant's “weak” chin and other facial features with feelings of compassion and care, a characteristic that helps promote the child's survival.38,39 Subjects who had high psychoticism scores (.50) also perceived that their dental appearance was less attractive than was perceived by subjects with low psychoticism scores (\50), (Table V). Persons with a high psychoticism score tend to be more solitary and less influenced by peer and society expectations, and thus might have less regard for facial profile and dental attractiveness norms.
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CONCLUSIONS
There were significant differences between the normative assessments made by orthodontists and the self-perceptions of young Chinese adults regarding their facial profiles and dental esthetics (P \0.05). The perceptions of the young adults were also significantly affected by sex and the personality trait of psychoticism (P \0.05). Therefore, the null hypothesis was rejected. REFERENCES 1. Mugonzibwa EA, Kuijpers-Jagtman AM, van't Hof MA, Kikwilu EN. Perceptions of dental attractiveness and orthodontic treatment need among Tanzanian children. Am J Orthod Dentofacial Orthop 2004;125:426-33. 2. Rosvall MD, Fields HW, Ziuchkovski J, Rosenstiel SF, Johnston WM. Attractiveness, acceptability, and value of orthodontic appliances. Am J Orthod Dentofacial Orthop 2009;135:276.e1-e12. 3. Bonetti GA, Alberti A, Sartini C, Parenti SI. Patients' self-perception of dentofacial attractiveness before and after exposure to facial photographs. Angle Orthod 2011;81:517-24. 4. Gray PO. Psychology. 5th ed. New York: Worth Publishers; 2006. p. 537-8, 542, 555. 5. Xu TM, Korn EL, Liu Y, Oh HS, Lee KH, Boyd RL, et al. Facial attractiveness: ranking of end-of-treatment facial photographs by pairs of Chinese and US orthodontists. Am J Orthod Dentofacial Orthop 2008;134:74-84. 6. Scavone H Jr, Zahn-Silva W, Valle-Corotti KM, Nahas ACR. Soft tissue profile in white Brazilian adults with normal occlusions and well-balanced faces. Angle Orthod 2008;78:58-63. 7. Hwang HS, Kim WS, McNamara JA Jr. Ethnic differences in the soft tissue profile of Korean and European-American adults with normal occlusions and well-balanced faces. Angle Orthod 2002;72:72-80. 8. Basciftci FA, Uysal T, Buyukerkmen A. Craniofacial structure of Anatolian Turkish adults with normal occlusions and wellbalanced faces. Am J Orthod Dentofacial Orthop 2004;125:366-72. 9. Mejia-Maidl M, Evans CA, Viana G, Anderson NK, Giddon DB. Preferences for facial profiles between Mexican Americans and Caucasians. Angle Orthod 2005;75:953-8. 10. Zhang YF, Xiao L, Li J, Peng YR, Zhao Z. Young people's esthetic perception of dental midline deviation. Angle Orthod 2010;80:515-20. 11. Trulsson U, Strandmark M, Mohlin B, Berggren U. A qualitative study of teenagers' decisions to undergo orthodontic treatment with fixed appliance. J Orthod 2002;29:197-204. 12. Zange SE, Ramos AL, Cuoghi OA, de Mendonc¸a MR, Suguino R. Perceptions of laypersons and orthodontists regarding the buccal corridor in long- and short-face individuals. Angle Orthod 2011; 81:86-90. 13. Pithon MM, Santos AM, Couto FS, da Silva Coqueiro R, Livia de Freitas LMA, da Souza RA, et al. Perception of the esthetic impact of mandibular incisor extraction treatment on laypersons, dental professionals, and dental students. Angle Orthod 2012;82:732-8. 14. Strickland B. The Gale encyclopedia of psychology. 2nd ed. Farmington Hills, Mich: Gale Group; 2001. p. 12-3. 15. Matsumoto D. The Cambridge dictionary of psychology. Cambridge, United Kingdom: Cambridge University Press; 2009. p. 201. 16. Sforza C, Laino A, D'Alessio R, Grandi G, Tartaglia GM, Ferrario VF. Soft-tissue facial characteristics of attractive and normal adolescent boys and girls. Angle Orthod 2008;78:799-807. 17. Edler R, Agarwal P, Wertheim D, Greenhill D. The use of anthropometric proportion indices in the measurement of facial attractiveness. Eur J Orthod 2006;28:274-81.
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18. Kokich VO, Kokich VG, Kiyak HA. Perceptions of dental professionals and laypersons to altered dental esthetics: asymmetric and symmetric situations. Am J Orthod Dentofacial Orthop 2006;130: 141-51. 19. Kiekens RMA, van't Hof MA, Straatman H, Kuijpers-Jagtman AM, Maltha JC. Influence of panel composition on aesthetic evaluation of adolescent faces. Eur J Orthod 2007;29:95-9. 20. Rivera SM, Hatch JP, Rugh JD. Psychological factors associated with orthodontic and orthognathic surgical treatment. Semin Orthod 2000;6:259-69. 21. Tung AW, Kiyak A. Psychological influences on the timing of orthodontic treatment. Am J Orthod Dentofacial Orthop 1998;113: 29-39. 22. Abed Y, Har-Zion G, Redlich M. Lip posture following debonding of labial appliances based on conventional profile photographs. Angle Orthod 2009;79:235-9. 23. Dimaggio FR, Ciusa V, Sforza C, Ferrario VF. Photographic softtissue profile analysis in children at 6 years of age. Am J Orthod Dentofacial Orthop 2007;132:475-80. 24. Fernandez-Riveiro P, Smyth-Chamosa E, Suarez-Quintanilla D, Suarez-Cunqueiro M. Angular photogrammetric analysis of the soft tissue facial profile. Eur J Orthod 2003;25:393-9. 25. Foster FJ. Profile preferences among diversified groups. Angle Orthod 1973;43:34-40. 26. Czarnecki ST, Nanda RS, Currier GF. Perceptions of a balanced facial profile. Am J Orthod Dentofacial Orthop 1993;104:180-7. 27. Legan HL, Burstone CJ. Soft tissue cephalometric analysis for orthognathic surgery. J Oral Surg 1980;38:744-51. 28. Wang X, Zhang ZK, Wang HJ, Yang F, Song H. Cephalometric analysis of soft tissue facial profile in attractive Chinese. J Compr Stomatol 1991;7:86-9. 29. Brook PH, Shaw WC. The development of an index of orthodontic treatment priority. Eur J Orthod 1989;11:309-20. 30. Eysenck JJ, Eysenck SBG. Manual for the Eysenck personality questionnaire. San Diego, Calif: Educational and Industrial Testing Service; 1975. 31. de Paula J unior DF, Santos NC, da Silva ET, Nunes MF, Leles CR. Psychosocial impact of dental esthetics on quality of life in adolescents. Angle Orthod 2009;79:1188-93. 32. Zhu H, Song Z, Deng Y. Early stage interpersonal perception and selection in internet instant messaging. Chinese Mental Health J 2010;24:224-7. 33. Wood W, Eagly AH. A cross-cultural analysis of the behavior of women and men: implications for the origins of sex differences. Psychol Bull 2002;128:699-727. 34. Wells BE, Twenge JM. Changes in young people's sexual behavior and attitudes, 1943-1999: a cross-temporal meta-analysis. Rev Gen Psychol 2005;9:249-61. 35. Hittelman JH, Dickes R. Sex differences in neonatal eye contact time. Merrill-Palmer Quarterly: J Develop Psychol 1979;25:171-84. Available at: http://www.jstor.org/discover/10.2307/23083747?uid5 2129&uid52&uid570&uid54&sid521103720293517. Accessed April 21, 2014. 36. Osofsky JD, O'Connell EJ. Patterning of newborn behavior in an urban population. Child Develop 1977;48:532-6. 37. American Dental Association. American Dental Association principles of ethics and code of professional conduct, with official advisory opinions revised to April 2012. Available at: http://www.ada. org/sections/about/pdfs/ada_code.pdf. Accessed May 9, 2013. 38. Alley TR. Head shape and the perception of cuteness. J Develop Psychol 1981;17:650-4. 39. Kalikow TJ. Konrad Lorenz's ethological theory: explanation and ideology, 1938-1943. J Hist Biol 1983;16:39-73.
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Differences in facial profile and dental esthetic perceptions between young adults and orthodontists Lu Yin,a Mingchun Jiang,b Wenjing Chen,c Roger J. Smales,d Qingzhu Wang,e and Lei Tangf Nanjing, People's Republic of China, and Adelaide, Australia
Introduction: The principal aim of this study was to investigate differences in perception of soft-tissue facial profiles and dental esthetics between young Chinese adults and orthodontists. Methods: Eight hundred ninety-two subjects (444 male, 448 female), ages 16 to 24 years, chose 1 image from among 5 profile silhouettes and from among 10 ranked color photographs of the aesthetic component (AC) of the index of orthodontic treatment need that most closely resembled their own profile and dental esthetic appearance, respectively. A panel of 20 orthodontists then independently repeated the same image selection process. Each subject also completed the Eysenck personality questionnaire for psychoticism. We used the MannWhitney U test and the Spearman rank correlation test, with statistical significance set at a 5 0.05. Results: Only 37.0% of subjects had straight profiles by objective orthodontic assessment, but 85.0% chose straight profiles by subjective self-perception. About 17.5%, mainly females, chose the mild convex as the ideal profile. Only 2.5% of the subjects were ranked 1 on the AC by orthodontists, but 43.6% chose 1, or ideal, by self-perception. Male subjects scored significantly higher than did female subjects for self-perceived facial profiles (more protruded chins) and for the AC (more attractive dental appearance). Subjects with high psychoticism T scores (.50) scored significantly lower for self-perceived facial profiles (more retruded chins) and on the AC (less attractive dental appearance). Conclusions: Young Chinese adults perceived their facial profiles and dental appearances to be significantly more straight and attractive, respectively, than did the orthodontists. A significant proportion of the young adults, mainly women, preferred a mild convex facial profile. High psychoticism scores might significantly affect the self-perception of orthodontic treatment needs. (Am J Orthod Dentofacial Orthop 2014;145:750-6)
a Associate clinical professor, Hospital of Nanjing Army Command College, Nanjing, People's Republic of China. b Associate professor and department chair, Hospital of Nanjing Army Command College, Nanjing, People's Republic of China. c Professor and department chair, Department of Orthodontics, College of Stomatology, Nanjing Medical University, Nanjing, People's Republic of China. d Visiting research fellow, School of Dentistry, Faculty of Health Sciences, University of Adelaide, Adelaide, Australia. e Lecturer, Department of Orthodontics, College of Stomatology, Nanjing Medical University, Nanjing, People's Republic of China. f Lecturer, Research Center, Nanjing Army Command College, Nanjing, People's Republic of China. All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported. Supported by the Natural Science Foundation of Jiangsu Province (grant number BK2012528), the Foundation of Health Bureau in Jiangsu Province (grant number Z201212), and the Priority Academic Program Development of Jiangsu Higher Education Institutions. Address correspondence to: Wenjing Chen, Department of Orthodontics, College of Stomatology, Nanjing Medical University, Nanjing 210029, PR China; e-mail, [email protected]. Submitted, June 2013; revised and accepted, January 2014. 0889-5406/$36.00 Copyright Ó 2014 by the American Association of Orthodontists. http://dx.doi.org/10.1016/j.ajodo.2014.01.021
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sthetics is a key motivational reason for patients seeking orthodontic treatment.1,2 The perceptions of facial profile and dental esthetics are essentially based on how subjects evaluate themselves.3 However, people vary in their emotions, thinking, and behavior, and these differences create individualism.4 Perceptions of esthetics also differ between laypersons and orthodontists.5-9 The professional opinions of orthodontists regarding dentofacial esthetics are made more objective by guidelines, norms, and ideal ratios and angles. But the perceptions of laypersons are largely motivated by subjective feelings such as the “beauty culture” in their peer groups and social norms in general.10,11 Some studies have found obvious differences in perceptions among groups of laypersons, dental students, and orthodontists.12,13 During postpuberty and early adulthood, young adults are an integral part of orthodontic patients. During the period of transition from adolescence to adulthood, young adults possess the typical age characteristics for their psychological behavior.14 The most
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Table I. Distribution by subjects' sex, geographic region of high schools attended, and age Geographic region of the subjects' high schools (n)
Male (444) Female (448) Total (892)
Extra-large and large cities 167 157 324
Medium cities 147 151 298
Small cities and rural areas 130 140 270
Age (y) Mean (SD) 18.74 (1.51) 19.03 (1.64) 18.81 (1.57)
Minimum 16 16 16
Maximum 23 24 24
the personality traits of young adults and their potential perceptions of facial profiles and dental esthetics. Therefore, in this study, we aimed to investigate the self-perceptions of facial profiles and dental esthetics among young adults, and to evaluate differences between self-perceptions and orthodontists' assessments. We also examined whether the sex and personality traits of young adults might affect their esthetic perceptions. The null hypothesis was that in a selected group of young Chinese adults assessing their soft-tissue facial profiles and dental esthetics, there are no significant differences between their self-assessments and those of orthodontists, and that the self-assessments are not significantly affected by personality traits. MATERIAL AND METHODS
Fig 1. Original male (left) and female (right) straight profile images.
central concept in personality psychology is the trait, which can be used to predict and explain a significant fraction of a subject's behavior. Eysenck claimed that personality could be described based on 3 fundamental dimensions or traits.15 Psychoticism, 1 of these traits, subsumed a variety of habitual behaviors: eg, aggressive, egocentric, creative, impulsive, and lacking empathy. Because patients who receive orthodontic treatment need to gain satisfaction from improving their esthetics, the self-perceptions of young adults are important indicators when deciding to undertake treatment, and this might complement conventional clinical evaluation. Although some authors have concluded that the professional opinions of orthodontists are generally more critical than those of laypersons when assessing dentofacial esthetics, few authors have investigated the selfperceptions of facial profiles and dental esthetics among young adults.16-19 Some studies have found that psychological factors do have certain effects on the perception of facial profile and dental esthetics.20,21 But few studies have investigated the relationship between
Students from 3 Chinese universities attended general health and oral health examinations at the Hospital of Nanjing Army Command College in 2011. Three universities were randomly selected from the 9 universities in the Pukou district in Nanjing, and the university classes were also randomly chosen. A total of 892 subjects gave their approval to participate in the study. Distributions by sex, geographic regions of the high schools attended, and ages are shown in Table I. Students were excluded if they had a history of orthodontic treatment or facial surgery, or a background of stomatology education. The study was approved by the ethics institutional review board of the Hospital of Nanjing Army Command College. All students received written information about the aims and procedures of the research and were told that participation was voluntary. Soft-tissue facial profiles can be assessed by means of standardized silhouettes and photographs.22-24 However, to reduce subjectivity, facial silhouettes rather than facial profile photographs were viewed by the subjects when scoring their facial profiles.25,26 According to selected landmarks, based on currently accepted criteria of softtissue measurements, representative straight-profile silhouettes of male and female subjects (Fig 1) were first drawn using Photoshop (CS 8.0.1; Adobe Systems, San Jose, Calif).22,27,28 A straight profile is generally considered to be the ideal for facial esthetics. Based on 2 straight profile silhouettes for males and females, an
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Fig 2. Pogonion manipulations of the female (upper) and the male (lower) straight facial profile images. From left to right, image 1 (protruded 12 ), image 2 (protruded 6 ), image 3 (straight), image 4 (retruded 6 ), and image 5 (retruded 12 ).
additional series of profile silhouettes was then generated by altering the original position of pogonion, which was protruded and then retruded by 6 and 12 from the straight profiles. The changes were artistically modified to maintain soft-tissue continuity and sex distinctions. The manipulated silhouettes formed 2 sets of male and female profile images. The scores for the profiles were the following: 1, severe concave; 2, mild concave; 3, straight; 4, mild convex; and 5, severe convex (Fig 2). The aesthetic component (AC) of the index of orthodontic treatment need is one dental appearance scale used to measure perceptions of dental esthetics.29 The AC consists of a scale of 10 color photographs showing different levels of dental attractiveness: 1 represents the most attractive, and 10 the least attractive arrangement of teeth in the AC, where 1 is identified with the ideal for dental esthetics. Personality trait theorists have developed many questionnaires to assess personality.4 The Eysenck personality questionnaire, which is highly reliable with strong evidence of validity, is one of the best-known and the most widely used for personality assessment in China.30 A psychologist (MC.J.) assessed all subjects and then changed the raw scores into standard T scores.
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The specially designed questionnaire comprised 4 sections: (1) sociodemographic information, (2) male and female images of facial profiles, (3) the AC, and (4) the Eysenck personality questionnaire. The first section of the questionnaire focused on the subjects' sociodemographic data: sex, birth date, family income, and level of education. The image-based questionnaire of facial profile had 2 parts: “Select the image that you think has the most attractive facial profile” and “Select the image that you think most closely represents your facial profile.” The subjects were asked to use numbers 1 to 5 to select the images from the relevant profile silhouettes of the sexes. The AC also had 2 parts: “Select the image that you think has the most attractive teeth” and “Select the image that you think most closely represents your teeth.” The subjects were asked to use numbers 1 to 10 to select images from the AC. The Eysenck personality questionnaire was the last section. The subjects were given 20 minutes to complete anonymously the questionnaires, which were marked by numeric codes. For each subject, we used a digital camera (EOS Rebel-D; Canon, Tokyo, Japan) to obtain 2 photographs of the right facial profile and frontal view of the teeth.
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Table II. Distribution by judges' sex, age, and specialty
experience n
Specialty Age (y) experience (y) Male Female Mean (SD) Mean (SD) Professors 1 1 46.75 (4.35) 23.00 (4.69) Associate professors 1 1 Associate clinical 3 3 33.67 (4.50) 11.83 (4.36) professors Graduate students 4 6 25.4 (1.43) 3.56 (1.33) Total 9 11 32.15 (8.88) 10.05 (8.15)
The subjects' photographs were marked with the same numeric codes as the questionnaires. A professional panel of orthodontists was selected to assess the subjects' photographs. This panel consisted of 20 orthodontists who practiced in the orthodontic departments at the Affiliated Hospital of Stomatology of Nanjing Medical University and the Hospital of Nanjing Army Command College. Their demographic information is included in Table II. The 2 professors instructed the other orthodontists in the evaluation of the softtissue facial profiles and the application of the AC over 2 weeks before this study started. Using the 2 sets of manipulated facial profile silhouettes and the AC, the professional panel scored the subjects' facial profiles and dental esthetics. The mean scores of the panel were increased or decreased to the nearest whole number before being analyzed. Statistical analysis
All scores were entered into the SPSS statistical software package (version 13.0; SPSS, Chicago, Ill). Data distributions were presented as means and standard deviations and were analyzed using the nonparametric Mann-Whitney U test and the Spearman rank correlation test. The probability level for statistical significance was set at a 5 0.05. The scores for 50 subjects were repeated by the same panel after a 2-week interval. The panel's kappa scores were 0.92 for the facial profiles and 0.86 for dental esthetics, indicating good agreement.
significant proportion (17.5%) of subjects also selected the mild convex profile as ideal. Table IV shows the distribution of the AC results, which were also significantly different between the subjects and the orthodontists (P \0.001). Most of the orthodontists' assessments were scores 3, 4, and 5 (22.1%, 21.1%, and 23.1%, respectively); this contrasted with the subjects’ own perceived dental esthetic assessments, where most photographic image scores were 1, 2, and 3 (43.6%, 27.5%, and 20.1%, respectively). The subjects' perceived mean AC score (2.15 6 1.65) was significantly more favorable than the orthodontists' mean AC score (4.03 6 1.64). Not surprisingly, most subjects selected score 1 (88.8%) as the ideal perceived dental appearance, with no scores greater than 4 selected. Table V shows that there were significant differences between the male and female subjects when comparing the differences in scores between the orthodontists and the subjects. Male subjects had greater differences than did female subjects for their own perceived facial profiles (more protruded chins) and dental esthetics (more attractive), but fewer differences than female subjects for the perceived ideal facial profile and ideal dental appearance. Apart from 1 instance (P 5 0.97), significant differences were also present between the low and high T scores for psychoticism when comparing the differences between the orthodontists and the subjects. (The T scores were \50 for 692 subjects and .50 for 200 subjects.) Subjects with T scores greater than 50 had fewer differences than did those with scores less than 50 for their own perceived facial profiles (less protruded chins) and dental esthetics (less attractive), and also fewer differences than those with scores less than 50 for the perceived ideal facial profile. There were no significant differences between subjects with high and low T scores for their perceived ideal dental esthetics. Table VI shows that with 1 exception, for psychoticism (P 5 0.71), both sex and psychoticism were significantly and negatively correlated with the differences in scores between the orthodontists and the subjects for facial profiles and dental esthetics (AC). However, the Spearman rank correlation values were low. To some extent, sex and psychoticism results mirrored each other.
RESULTS
Table III shows the distribution of the facial profile results, which were significantly different between the subjects and the orthodontists (P \0.0001). Although the assessments by the orthodontists (37%) and the subjects (85%) favored the straight profile (score 3), these assessments were heavily skewed by the subjects who closely equated their own perceived facial profiles with the perceived ideal facial profile (78.5%). However, a
DISCUSSION
Only 37.0% of the subjects had straight facial profiles by the more objective orthodontic assessments, but 85.0% chose straight profiles by subjective selfperceptions (Table III). The results suggest that the young adults' subjective perceptions of their profiles are inaccurate; this is not surprising, since people cannot directly obtain visual information of their profiles by looking at
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Table III. Observations from facial silhouettes Profile Silhouettes Assessment 1 OAP 46 (5.2%) SAP 4 (0.4%) c2 5 466.5; df 5 4; P \0.0001 SIP 2 (0.2%)
2 188 (21.1%) 34 (3.8%)
3 330 (37.0%) 758 (85.0%)
4 254 (28.5%) 90 (10.1%)
5 74 (8.3%) 6 (0.7%)
AC mean (SD)* 3.14 (1.00) 3.07 (0.42)
18 (2.0%)
700 (78.5%)
156 (17.5%)
16 (1.8%)
3.19 (0.49)
OAP, Orthodontist assessment of profile; SAP, subject assessment of profile; SIP, subject ideal assessment of profile. *Mean (SD) score for ranking of profile images.
Table IV. Observations from a set of 10 photographs in the AC Aesthetic Component Assessment 1 2 3 4 5 6 7 8 9 10 AC mean (SD)* OAAC 22 (2.5%) 149 (16.7%) 197 (22.1%) 188 (21.1%) 206 (23.1%) 48 (5.4%) 52 (5.8%) 26 (2.9%) 3 (3%) 1 (1%) 4.03 (1.64) SAAC 389 (43.6%) 245 (27.5%) 179 (20.1%) 31 (3.8%) 5 (6.0%) 8 (9.0%) 8 (9.0%) 15 (1.7%) 8 (9%) 4 (4%) 2.15 (1.65) c2 5 1798; df 5 18; P \0.001 SIAC 792 (88.8%) 52 (5.8%) 31 (3.8%) 17 (1.9%) 0 0 0 0 0 0 1.20 (0.67) OAAC, Orthodontist assessment of AC; SAAC, subject assessment of AC; SIAC, subject ideal assessment of AC. *Mean (SD) score for ranking of photographs.
Table V. Comparison of mean (SD) scores, from differences in assessments of facial profile and of AC, between sex and psychoticism Sex Assessment OAP-SAP OAAC-SAAC SIP-OIP SIAC-OIAC
Sex M F M F M F M F
Mean (SD) 0.11 (1.04) 0.37 (1.22) 1.99 (1.85) 0.74 (2.33) 0.16 (0.48) 0.50 (0.56) 0.09 (0.46) 1.26 (1.24)
Psychotiscism Z score 2.167
P value 0.03*
3.158
0.002y
4.510
0.000z
7.168
0.000z
Ps \50 .50 \50 .50 \50 .50 \50 .50
Mean (SD) 0.13 (1.08) 0.15 (0.97) 2.06 (1.69) 1.22 (2.51) 0.14 (0.45) 0.33 (0.59) 0.21 (0.69) 0.18 (0.58)
Z score 2.566
P value 0.01y
2.321
0.02*
3.007
0.003y
0.040
0.97
Statistical significance: *P \0.05; yP \0.01; zP \0.001. Ps, Psychoticsm; M, male; F, female; OAP, orthodontist assessment of profile; SAP, subject assessment of profile; OAAC, orthodontist assessment of the AC; SAAC, subject assessment of the AC; SIP, subject ideal profile; OIP, orthodontist ideal profile (5 3); SIAC, subject ideal AC; OIAC, orthodontist ideal AC (5 1).
a mirror. According to the theory of Gestalt psychology, the canonic perspective of the face is generally obtained from the frontal view rather than from less-informative perspectives such as profile or bird's-eye views. Some 78.5% of the subjects chose the straight profile, and 17.5% chose the mild convex profile as the ideal facial profile (Table III). Orthodontists, whose concepts of profile esthetics are influenced by their specialist training, prefer to use cephalometric measurements to assess facial profiles. Their treatment plans and outcomes are often devised to meet the more objective standards of orthodontic parameters and norms that reflect only the viewpoints of professionals, and which were generated in Western countries. However, according to
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cognitive dissonance theory, laypersons' perceptions of facial profiles are adopted from the social norms and “beauty culture” in their peer groups and society in general. Furthermore, social norms and “beauty culture” change with time and the effects of mass media, culture, race, and place. Therefore, the norms of the young adults' peer groups and society, and not the orthodontic norms, are the most important factors in facial-profile perceptions. Hence, a significant proportion of young Chinese adults preferred a mild convex facial profile rather than a straight profile. The results of the AC rankings show that the subjects rated their dental appearance significantly more favorably than did the orthodontists (Table IV). It would
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Table VI. Correlations (rs) between differences in as-
sessments and sex scores, and between differences in assessments and psychoticism scores Correlation and P value Sex (male/female) Psychoticism rs 0.103 0.097 P value 0.03* 0.04* OAAC-SAAC rs 0.222 0.182 0.009y P value 0.001z SIP-OIP rs 0.214 0.134 P value 0.000z 0.004y SIAC-OIAC rs 0.503 0.027 P value 0.000z 0.71 Assessment OAP-SAP
Statistical significance: *P \0.05; yP \0.01; zP \0.001. OAP, Orthodontist assessment of profile; SAP, subject assessment of profile; OAAC, orthodontist assessment of the AC; SAAC, subject assessment of the AC; SIP, subject ideal profile; OIP, orthodontist ideal profile (5 3); SIAC, subject ideal AC; OIAC, orthodontist ideal AC (5 1).
appear that the young adults were not unduly concerned about minor dental irregularities adversely affecting their appearance. It is not uncommon to observe that some patients with severe malocclusions are satisfied with or indifferent to their dental esthetics, whereas others are concerned about minor irregularities. In many patients, the principal motive for orthodontic treatment is the improvement of physical attractiveness, regardless of the functional severity of the deformity. Young adults, who lack professional orthodontic knowledge, might perceive their dental esthetics inaccurately. Therefore, orthodontists should discuss with their patients such possible misconceptions. Although most (88.8%) of the subjects preferred image 1 as the ideal dental appearance, some subjects preferred images 2, 3, and 4 for the AC (Table IV). Disability and disease do not always negatively affect subjective perceptions of well-being; even when they do, their impact depends on the person's expectations and preferences; on material, social, and psychological resources; and, more importantly, on socially and culturally derived values.31 Today, many close friendships and valued acquaintanceships involve young adults who first met by instant Internet messages, e-mails, chat rooms, and blogs. One survey of instant messaging indicated that during the early stages of interpersonal perception and selection, age, nickname, and self-explanation were the most important reasons for choosing a friend, rather than facial features, blood type, and occupation.32 Thus, in cyberspace, where important visual and auditory information might be absent, young Chinese adults display higher-than-expected individualism and egocentric tendencies. Hence, dental irregularities
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have little significance here when making new friends. Therefore, when an orthodontist plans to improve a patient's dental appearance, it is important first to know whether the orthodontist's ideal concept of esthetics will coincide with that of the patient. There were significant differences between the male and female subjects in their self-perceptions of facial profiles and dental esthetics (Table V). A straight profile was preferred by the male subjects, and a mild convex profile was preferred by the female subjects. People who subscribe to traditional sex stereotypes tend to assume that women with a mild convex profile are more beautiful, kind, naïve, and weak, and less socially dominant. By contrast, people tend to see men as more firm, alert, strong, and coordinated. Many studies have suggested that masculinity and femininity are significantly shaped by culture.33,34 Findings from the AC scores suggest that male subjects are more tolerant of less favorable dental esthetics than are female subjects, and that females are more critical in their perceptions of adverse impacts related to dental esthetics (Table V). Psychosocial research shows that males and females, even in early infancy, behave differently.35,36 Women tend to “internalize” their discomfort; they dwell mentally on their distress and seek causes within themselves. By contrast, men more often “externalize” their discomfort; they tend to look for causes outside themselves. Perhaps this is one of the reasons that females expressed greater awareness of facial profile and dental attractiveness than did males. In accordance with recent professional guidelines,37 orthodontists must realize how greatly their own assessments can differ from those of their patients regarding ideal facial profiles and dental appearances. Subjects who had high psychoticism scores (.50) perceived that they had a more mild convex (retruded chin) facial profile, and that the ideal facial profile was more convex than was perceived by subjects with low psychoticism scores (\50) (Table V). Personality traits appear to have some effect on facial profile perceptions. A common bias is that we tend to see a “strong” jaw as a sign of a firm and aggressive character. By contrast, a person with a “weak” jaw is seen as emotional and kind. Psychological studies suggest that people instinctively respond to an infant's “weak” chin and other facial features with feelings of compassion and care, a characteristic that helps promote the child's survival.38,39 Subjects who had high psychoticism scores (.50) also perceived that their dental appearance was less attractive than was perceived by subjects with low psychoticism scores (\50), (Table V). Persons with a high psychoticism score tend to be more solitary and less influenced by peer and society expectations, and thus might have less regard for facial profile and dental attractiveness norms.
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CONCLUSIONS
There were significant differences between the normative assessments made by orthodontists and the self-perceptions of young Chinese adults regarding their facial profiles and dental esthetics (P \0.05). The perceptions of the young adults were also significantly affected by sex and the personality trait of psychoticism (P \0.05). Therefore, the null hypothesis was rejected. REFERENCES 1. Mugonzibwa EA, Kuijpers-Jagtman AM, van't Hof MA, Kikwilu EN. Perceptions of dental attractiveness and orthodontic treatment need among Tanzanian children. Am J Orthod Dentofacial Orthop 2004;125:426-33. 2. Rosvall MD, Fields HW, Ziuchkovski J, Rosenstiel SF, Johnston WM. Attractiveness, acceptability, and value of orthodontic appliances. Am J Orthod Dentofacial Orthop 2009;135:276.e1-e12. 3. Bonetti GA, Alberti A, Sartini C, Parenti SI. Patients' self-perception of dentofacial attractiveness before and after exposure to facial photographs. Angle Orthod 2011;81:517-24. 4. Gray PO. Psychology. 5th ed. New York: Worth Publishers; 2006. p. 537-8, 542, 555. 5. Xu TM, Korn EL, Liu Y, Oh HS, Lee KH, Boyd RL, et al. Facial attractiveness: ranking of end-of-treatment facial photographs by pairs of Chinese and US orthodontists. Am J Orthod Dentofacial Orthop 2008;134:74-84. 6. Scavone H Jr, Zahn-Silva W, Valle-Corotti KM, Nahas ACR. Soft tissue profile in white Brazilian adults with normal occlusions and well-balanced faces. Angle Orthod 2008;78:58-63. 7. Hwang HS, Kim WS, McNamara JA Jr. Ethnic differences in the soft tissue profile of Korean and European-American adults with normal occlusions and well-balanced faces. Angle Orthod 2002;72:72-80. 8. Basciftci FA, Uysal T, Buyukerkmen A. Craniofacial structure of Anatolian Turkish adults with normal occlusions and wellbalanced faces. Am J Orthod Dentofacial Orthop 2004;125:366-72. 9. Mejia-Maidl M, Evans CA, Viana G, Anderson NK, Giddon DB. Preferences for facial profiles between Mexican Americans and Caucasians. Angle Orthod 2005;75:953-8. 10. Zhang YF, Xiao L, Li J, Peng YR, Zhao Z. Young people's esthetic perception of dental midline deviation. Angle Orthod 2010;80:515-20. 11. Trulsson U, Strandmark M, Mohlin B, Berggren U. A qualitative study of teenagers' decisions to undergo orthodontic treatment with fixed appliance. J Orthod 2002;29:197-204. 12. Zange SE, Ramos AL, Cuoghi OA, de Mendonc¸a MR, Suguino R. Perceptions of laypersons and orthodontists regarding the buccal corridor in long- and short-face individuals. Angle Orthod 2011; 81:86-90. 13. Pithon MM, Santos AM, Couto FS, da Silva Coqueiro R, Livia de Freitas LMA, da Souza RA, et al. Perception of the esthetic impact of mandibular incisor extraction treatment on laypersons, dental professionals, and dental students. Angle Orthod 2012;82:732-8. 14. Strickland B. The Gale encyclopedia of psychology. 2nd ed. Farmington Hills, Mich: Gale Group; 2001. p. 12-3. 15. Matsumoto D. The Cambridge dictionary of psychology. Cambridge, United Kingdom: Cambridge University Press; 2009. p. 201. 16. Sforza C, Laino A, D'Alessio R, Grandi G, Tartaglia GM, Ferrario VF. Soft-tissue facial characteristics of attractive and normal adolescent boys and girls. Angle Orthod 2008;78:799-807. 17. Edler R, Agarwal P, Wertheim D, Greenhill D. The use of anthropometric proportion indices in the measurement of facial attractiveness. Eur J Orthod 2006;28:274-81.
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18. Kokich VO, Kokich VG, Kiyak HA. Perceptions of dental professionals and laypersons to altered dental esthetics: asymmetric and symmetric situations. Am J Orthod Dentofacial Orthop 2006;130: 141-51. 19. Kiekens RMA, van't Hof MA, Straatman H, Kuijpers-Jagtman AM, Maltha JC. Influence of panel composition on aesthetic evaluation of adolescent faces. Eur J Orthod 2007;29:95-9. 20. Rivera SM, Hatch JP, Rugh JD. Psychological factors associated with orthodontic and orthognathic surgical treatment. Semin Orthod 2000;6:259-69. 21. Tung AW, Kiyak A. Psychological influences on the timing of orthodontic treatment. Am J Orthod Dentofacial Orthop 1998;113: 29-39. 22. Abed Y, Har-Zion G, Redlich M. Lip posture following debonding of labial appliances based on conventional profile photographs. Angle Orthod 2009;79:235-9. 23. Dimaggio FR, Ciusa V, Sforza C, Ferrario VF. Photographic softtissue profile analysis in children at 6 years of age. Am J Orthod Dentofacial Orthop 2007;132:475-80. 24. Fernandez-Riveiro P, Smyth-Chamosa E, Suarez-Quintanilla D, Suarez-Cunqueiro M. Angular photogrammetric analysis of the soft tissue facial profile. Eur J Orthod 2003;25:393-9. 25. Foster FJ. Profile preferences among diversified groups. Angle Orthod 1973;43:34-40. 26. Czarnecki ST, Nanda RS, Currier GF. Perceptions of a balanced facial profile. Am J Orthod Dentofacial Orthop 1993;104:180-7. 27. Legan HL, Burstone CJ. Soft tissue cephalometric analysis for orthognathic surgery. J Oral Surg 1980;38:744-51. 28. Wang X, Zhang ZK, Wang HJ, Yang F, Song H. Cephalometric analysis of soft tissue facial profile in attractive Chinese. J Compr Stomatol 1991;7:86-9. 29. Brook PH, Shaw WC. The development of an index of orthodontic treatment priority. Eur J Orthod 1989;11:309-20. 30. Eysenck JJ, Eysenck SBG. Manual for the Eysenck personality questionnaire. San Diego, Calif: Educational and Industrial Testing Service; 1975. 31. de Paula J unior DF, Santos NC, da Silva ET, Nunes MF, Leles CR. Psychosocial impact of dental esthetics on quality of life in adolescents. Angle Orthod 2009;79:1188-93. 32. Zhu H, Song Z, Deng Y. Early stage interpersonal perception and selection in internet instant messaging. Chinese Mental Health J 2010;24:224-7. 33. Wood W, Eagly AH. A cross-cultural analysis of the behavior of women and men: implications for the origins of sex differences. Psychol Bull 2002;128:699-727. 34. Wells BE, Twenge JM. Changes in young people's sexual behavior and attitudes, 1943-1999: a cross-temporal meta-analysis. Rev Gen Psychol 2005;9:249-61. 35. Hittelman JH, Dickes R. Sex differences in neonatal eye contact time. Merrill-Palmer Quarterly: J Develop Psychol 1979;25:171-84. Available at: http://www.jstor.org/discover/10.2307/23083747?uid5 2129&uid52&uid570&uid54&sid521103720293517. Accessed April 21, 2014. 36. Osofsky JD, O'Connell EJ. Patterning of newborn behavior in an urban population. Child Develop 1977;48:532-6. 37. American Dental Association. American Dental Association principles of ethics and code of professional conduct, with official advisory opinions revised to April 2012. Available at: http://www.ada. org/sections/about/pdfs/ada_code.pdf. Accessed May 9, 2013. 38. Alley TR. Head shape and the perception of cuteness. J Develop Psychol 1981;17:650-4. 39. Kalikow TJ. Konrad Lorenz's ethological theory: explanation and ideology, 1938-1943. J Hist Biol 1983;16:39-73.
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