Effect of the ethnic, profession, gender, and social background on the perception of upper dental midline deviations in smile esthetics by Chinese and Black raters

Mazen Musa; Riham Awad; Abdalla Mohammed; Hibatalrahman Abdallah; Mohamed Elhoumed; Leena Al-Waraf; Wanting Qu; Najah Alhashimi; Xi Chen; Shuang Wang

doi:10.1186/s12903-023-02893-4

Effect of the ethnic, profession, gender, and social background on the perception of upper dental midline deviations in smile esthetics by Chinese and Black raters

BMC Oral Health. 2023 Apr 14;23(1):214. doi: 10.1186/s12903-023-02893-4.

Authors

Mazen Musa^{1

2

3

4

5}, Riham Awad⁶, Abdalla Mohammed⁷, Hibatalrahman Abdallah⁸, Mohamed Elhoumed^{9

10}, Leena Al-Waraf⁴, Wanting Qu^{1

2

3}, Najah Alhashimi¹¹, Xi Chen⁴, Shuang Wang^{12

13

14}

Affiliations

¹ Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, People's Republic of China.
² Laboratory Center of Stomatology, College of Stomatology, Xi'an Jiaotong University, Xi'an, People's Republic of China.
³ Department of Orthodontics, College of Stomatology, Xi'an Jiaotong University, Xi'an, People's Republic of China.
⁴ Department of Stomatology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710004, People's Republic of China.
⁵ Department of Orthodontics, Al Tagana Dental Teaching Hospital, Faculty of Dentistry, University of Science and Technology Omdurman, Omdurman, Khartoum, 11111, Sudan.
⁶ Department of Pediatrics dentistry, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
⁷ University of Science and Technology Omdurman, Khartoum, Sudan.
⁸ Department of Prosthodontics, University of Khartoum, Khartoum, Sudan.
⁹ Department of Epidemiology and Biostatistics, School of Public Health, Xi'an Jiaotong University, Xi'an, People's Republic of China.
¹⁰ National Institute of Public Health Research (INRSP), BP. 695, Nouakchott, Mauritania.
¹¹ Unit and Divisional Chief Orthodontics at Hamad Medical Corporation, and Associate Professor, College of Dental Medicine, Qatar University, Doha, Qatar.
¹² Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, People's Republic of China. wshuang@mail.xjtu.edu.cn.
¹³ Laboratory Center of Stomatology, College of Stomatology, Xi'an Jiaotong University, Xi'an, People's Republic of China. wshuang@mail.xjtu.edu.cn.
¹⁴ Department of Orthodontics, College of Stomatology, Xi'an Jiaotong University, Xi'an, People's Republic of China. wshuang@mail.xjtu.edu.cn.

Abstract

Background: The purpose of this study was to compare the perception of upper dental midline deviation on the attractiveness of a smile among raters from different ethnicities, professions, genders, and ages and measure to what extent the presence or absence of the associated smiling structures influence the raters' evaluations.

Methods: A male subject (26 years of age) with adequate smile characteristics was selected by 3 experienced orthodontists, and 561 raters from 2 different ethnic groups (281 Chinese raters and 280 Black raters) rated the subject's smile after the subject's upper dental midline was digitally altered from 0 to 5 mm using a 5-point Likert scale on 12 smile photographs divided into two groups: group 1, in the presence of smile related structures, two-thirds of the nose, lips, and chin (NLC), and group 2, in the absence of smile related structures, the lips only (L).

Results: There were statistically significant differences (p < 0.05) between the two ethnicities, in 2 mm and 4 mm in-group NLC and 5 mm in-group L, as well as the raters' profession to each midline shift of both groups (NLC) and (L) for both ethnicities except for 0 mm. Regarding the role of associated smile structures, the smile photos were observed in the presence of smile-associated structures, and in its absence (NLC × L), statistically significant differences (p < 0.05) were found when the deviation was 5 mm among the Chinese raters; in 1 mm, and 4 mm among the Black raters. Among different genders, statistical differences were only reported (p < 0.05) for Chinese raters for 5 mm in NLC, while statistical differences were observed for 2 mm and 3 mm in NLC for Black raters. For age categories, differences were observed (p < 0.05) for 4 mm, 5 mm in NLC and 4 mm, and 5 mm in L for Chinese raters, while 5 mm in NLC and 1 mm in L for Black raters.

Conclusion: Perception of the upper dental midline deviations was influenced by the factors of ethnicity, profession, presence or absence of smile-associated structures, as well as the gender and age of the raters.

Keywords: Layperson; Likert scale; Midline coincidence; Orthodontist; Smile.

Publication types

Comparative Study
Research Support, Non-U.S. Gov't

MeSH terms

Adult
Attitude of Health Personnel
Black People* / psychology
East Asian People* / psychology
Esthetics, Dental* / psychology
Female
Humans
Incisor / anatomy & histology
Male
Perception
Smiling* / psychology