title: Effect of mesiodistal angulation of the maxillary central incisors on esthetic perceptions of the smile in the frontal view.
abstract: BACKGROUND
  The purpose of this study was to analyze the effect of mesiodistal angulation of the maxillary central incisors on the smiling esthetics in young adults.
  
  
  METHODS
  Frontal smile photographs of a young man and a young woman were digitally modified to produce 28 smile images that were grouped into 4 series. These images were judged using visual analog scales by 52 orthodontists and 61 laypeople. The effects of the judges' professions, subjects' sexes, and photograph framings on the appreciation of smile esthetics with different mesiodistal angulations of the maxillary central incisors were evaluated. The data were analyzed with paired t tests, Dunnett t tests, and independent samples t tests; statistical significance was set at P <0.05.
  
  
  RESULTS
  The images were ranked less attractive as the mesiodistal angulation of the maxillary central incisors increased during smiling. No relationship was found between the judges' professions and the esthetic evaluations of incisal angulation, but the statistical analysis showed that both the subject's sex and the photograph framing were significant variables (P <0.05).
  
  
  CONCLUSIONS
  The mesiodistal angulation of the maxillary central incisors plays an essential role in smile esthetics in the frontal view. When formulating treatment plans, orthodontists should never underestimate the influence of mesiodistal angulation on smile attractiveness.
authors: Postgraduate student, Department of Prosthodontics, State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, Chengdu, China.
authors: Shuying
authors: S
authors: Yang
authors: Resident, Lanzhou Hospital of Stomatology, Lanzhou, China.
authors: Yunfei
authors: Y
authors: Guo
authors: Postgraduate student, Department of Orthodontics, State Key Laboratory of Oral Diseases, West China college of Stomatology, Sichuan University, Chengdu, China.
authors: Xianrui
authors: X
authors: Yang
authors: Private practice, Hangzhou, China.
authors: Feng
authors: F
authors: Zhang
authors: Associate professor, Department of Prosthodontics, State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, Chengdu, China.
authors: Jian
authors: J
authors: Wang
authors: Postgraduate student, Department of Orthodontics, State Key Laboratory of Oral Diseases, West China college of Stomatology, Sichuan University, Chengdu, China.
authors: Jingyi
authors: J
authors: Qiu
authors: Associate professor, Department of Orthodontics, State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, Chengdu, China. Electronic address: lijuan@scu.edu.cn.
authors: Juan
authors: J
authors: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D001291:Attitude of Health Personnel; D001294:Attitude to Health; D004955:Esthetics, Dental; D005260:Female; D006801:Humans; D007180:Incisor / Q000033:anatomy & histology*; D007396:Internship and Residency; D008297:Male; D008437:Maxilla / Q000033:anatomy & histology*; D009970:Orthodontics / Q000193:education; D000066792:Orthodontists / Q000523:psychology; D023861:Photography, Dental; D012737:Sex Factors; D012904:Smiling; D019228:Tooth Crown / Q000033:anatomy & histology; D064232:Visual Analog Scale; D055815:Young Adult