title: The SPA Factor or Not? Distinguishing Sex on the Basis of Stereotyped Tooth Characteristics.
abstract: OBJECTIVE
  The study examines whether faculty, dental students, or laypeople can determine the sex of a patient solely by looking at the shape of their teeth.
  
  
  METHODS
  Fifty faculty, 100 students, and 50 patients evaluated 40 photographed smiles for 8,000 observations. The subject group was comprised of 20 males and 20 females. Contingency table analysis was used to determine whether all study participants labeled the smiles similarly and to look for differences within each group. Care was taken to model the effect of individual variation. A nested logistic regression was employed to ascertain differences between faculty, students, and laypeople and to account for the correlation within subjects' responses.
  
  
  RESULTS
  It was expected that 50% of the smiles would be labeled as male and 50% as female. Statistical differences were found for the total group, as all participants were more likely to rate a smile as female (χ2 = 38.19, P < .0001). Using the odds ratio, study participants were 1.32 times more likely to view a smile as female.
  
  
  CONCLUSIONS
  Stereotyped "feminine" and "masculine" tooth anatomy characteristics could not predictably be related to the sample smiles either by faculty, students, or public.
authors.affiliation: Professor, Department of Prosthodontics, College of Dentistry, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Hottel
authors.affiliation: Associate Professor, Department of Bioscience Research, College of Dentistry, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: Chris S
authors.initials: CS
authors.lastname: Ivanoff
authors.affiliation: Professor, Section of Prosthodontics, Nova Southeastern University, Health Professions Division, Fort Lauderdale, Florida.
authors.forename: John
authors.initials: J
authors.lastname: Anotonelli
authors.affiliation: Former Adjunct Professor, Section of Prosthodontics, Nova Southeastern University, Health Professions Division, Fort Lauderdale, Florida.
authors.forename: William
authors.initials: W
authors.lastname: Balanoff
authors.affiliation: Private Practice specializing in pediatrics, Englishtown, New Jersey.
authors.forename: Rose Ann
authors.initials: RA
authors.lastname: Habib-Chiang
authors.affiliation: D-2 Dental Student, College of Dentistry, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: Stefan A
authors.initials: SA
authors.lastname: Hottel
mesh_terms: D000367:Age Factors; D003815:Dentists; D005260:Female; D017144:Focus Groups; D006801:Humans; D008297:Male; D009811:Odontometry / Q000379:methods*; D023861:Photography, Dental; D012727:Sex Characteristics; D012732:Sex Determination Analysis; D012904:Smiling; D013335:Students, Dental; D011795:Surveys and Questionnaires