title: A comparison of gingival display with a requested smile, Duchenne smile, grimace of disgust, and funnel-shaped expression.
abstract: BACKGROUND
  A patient's smile may not elicit the maximum amount of maxillary gingiva.
  
  
  OBJECTIVE
  The purpose of this study was to measure the amount of gingival display with 4 different facial expressions.
  
  
  METHODS
  Video images of 91 randomly selected adults were evaluated to measure the height of gingival display at the maxillary anterior teeth and first premolars when participants were asked to give their biggest smile (requested smile), make a Duchenne smile, mimic an intense grimace of disgust (grimace), and produce a funnel-shaped expression (funnel). Measurements were compared with the Friedman Test with post hoc comparisons (α=.05 for all tests).
  
  
  RESULTS
  The intraclass correlation coefficient was (95% CI)=0.913(0.623, 0.984). At the central and lateral incisors, the grimace and funnel expressions produced the greatest amounts of gingival display. At the canines and the first premolars, both smiles (requested and Duchenne) exhibited the largest amount of gingival display of the 4 facial expressions.
  
  
  CONCLUSIONS
  Neither smile type revealed a significantly greater amount of gingival display above the maxillary central or lateral incisors but the grimace and funnel facial expressions did (P ≤.001). Above the maxillary canines, both smiles displayed a significantly greater amount of gingiva than did the funnel expression (P<.001), but only the Duchenne smile displayed a greater amount than did the grimace expression (P=.05). Superiorly to the maxillary first premolars, both smile types revealed significantly greater amounts of soft tissue when compared with the other 2 facial expressions (P<.001).
authors.affiliation: Assistant Professor, Department of Restorative Dentistry, Loma Linda University School of Dentistry, Loma Linda, Calif. Electronic address: rwalter@llu.edu.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Walter
authors.affiliation: Graduate student, Combined Program in Prosthodontics and Implant Dentistry, Loma Linda, Calif.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Goodacre
authors.affiliation: Professor, Department of Restorative Dentistry, Loma Linda University School of Dentistry, Loma Linda, Calif.
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Goodacre
authors.affiliation: Associate Dean for Advanced Dental Education; Professor, Department of Restorative Dentistry, Loma Linda University School of Dentistry, Loma Linda, Calif.
authors.forename: W Patrick
authors.initials: WP
authors.lastname: Naylor
authors.affiliation: Assistant Professor, Department of Dental Educational Services, Loma Linda University School of Dentistry, Loma Linda, Calif.
authors.forename: Udochukwu
authors.initials: U
authors.lastname: Oyoyo
mesh_terms: D000328:Adult; D000368:Aged; D001641:Bicuspid / Q000033:anatomy & histology; D003481:Cuspid / Q000033:anatomy & histology; D003724:Dental Arch / Q000033:anatomy & histology; D004644:Emotions; D005149:Facial Expression; D005260:Female; D005881:Gingiva / Q000033:anatomy & histology*; D006801:Humans; D007180:Incisor / Q000033:anatomy & histology; D008297:Male; D008437:Maxilla / Q000033:anatomy & histology; D008875:Middle Aged; D012904:Smiling / Q000502:physiology; D055815:Young Adult