title: Effect of buccolingual inclinations of maxillary canines and premolars on perceived smile attractiveness.
abstract: BACKGROUND
  In this study, we aimed to investigate the effect of buccolingual inclinations of the maxillary canines and premolars on the perceived attractiveness of the smile when viewed from the frontal perspective.
  
  
  METHODS
  A smiling frontal photograph was taken of a man. A 3-dimensional digital dental model of this subject was constructed within which the buccolingual inclinations of the canines and premolars could be altered relative to the occlusal plane. Three-dimensional models of the altered digital models were then printed in resin and mounted on articulators. Frontal photos of the mounted models were taken and transferred to the smile image. A series of images was produced with the canines and premolars inclined buccally or lingually by different degrees. The smile images were assessed by 2 panels, orthodontists and laypeople.
  
  
  RESULTS
  There was a broad range of esthetic acceptability for the buccolingual inclinations of the maxillary canines and premolars. The range of preferred inclinations was not as broad. Smile esthetics was significantly compromised (P <0.01) when the canines were lingually inclined more than -12°, or the premolars were lingually inclined more than -15°, as perceived by orthodontists and laypersons. Buccally tipping the canines more than 6° also made the smile esthetics less satisfying (P <0.01).
  
  
  CONCLUSIONS
  It could be esthetically satisfying to position the teeth within the ranges of 0° to -7° of inclination for the canines and -3° to -11° of inclination for the premolars, as assessed by the orthodontists, or of 3° to -10° of inclination for the canines and 5° to -11° of inclination for the premolars, as assessed by the laypersons. Clinicians could exercise flexibility within this range, when compromising tooth positions for transverse jaw discrepancies.
authors: Postgraduate student, Department of Orthodontics, State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
authors: Hui
authors: H
authors: Xu
authors: Associate professor, Department of Orthodontics, State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
authors: Xianglong
authors: X
authors: Han
authors: Lecturer, Department of Orthodontics, State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
authors: Yanmin
authors: Y
authors: Wang
authors: Postgraduate student, Department of Orthodontics, State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
authors: Rui
authors: R
authors: Shu
authors: Postgraduate student, Department of Orthodontics, State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
authors: Yan
authors: Y
authors: Jing
authors: Postgraduate student, Department of Orthodontics, State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
authors: Ye
authors: Y
authors: Tian
authors: Assistant clinical professor, Department of Orthodontics, University of California at San Francisco, private practice, San Diego, Calif.
authors: Will A
authors: WA
authors: Andrews
authors: Adjunct professor, Department of Orthodontics, West Virginia University, Morgantown, WVa.
authors: Lawrence F
authors: LF
authors: Andrews
authors: Professor and chair, Departments of Orthodontics and Paediatrics, State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China. Electronic address: baiding@scu.edu.cn.
authors: Ding
authors: D
authors: Bai
mesh_terms: D000328:Adult; D001291:Attitude of Health Personnel; D001294:Attitude to Health; D001641:Bicuspid / Q000033:anatomy & histology*; D003481:Cuspid / Q000033:anatomy & histology*; D003815:Dentists / Q000523:psychology; D004955:Esthetics, Dental; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D007180:Incisor / Q000033:anatomy & histology; D008297:Male; D008437:Maxilla / Q000033:anatomy & histology*; D003765:Models, Dental; D009970:Orthodontics; D023861:Photography, Dental / Q000379:methods; D015203:Reproducibility of Results; D012904:Smiling; D019228:Tooth Crown / Q000033:anatomy & histology; D014584:User-Computer Interface; D064232:Visual Analog Scale; D055815:Young Adult