Tooth Shape Relates to Gender – A Widespread Misbelief

Objectives: Aim of this study was to verify the gender aspect of aesthetic guidelines for the upper front teeth proposed in educational books and publications by creating computer-generated composite images using a morphing program. Methods: The upper front teeth of 160 female and 160 male Caucasian students between 18 and 30 years were photographed. To make the morphing procedure technically possible, several absolute exclusion criteria were determined (for example: absent teeth, malposition). 37 male and 58 female photographs remained for generating composite images. Two composite images “average” (both female and male) were created out of 32 randomly picked photographs. Two composite images “content” and two composite images “discontent” were created by taking the self-evaluation of the photographed students into account. For this purpose photographs of students were used, who were most contented or discontented with the appearance of their teeth. A second group of participants (75 dentists and 75 laymen) evaluated the six composite images completing a short questionnaire. Results: The width-to-length-ratio of the central incisors ranged from 81.7 to 85.2% for the composite images “average” and “content”. For the images “discontent” width-to-length-ratio was above 89% and slight asymmetries of the central incisors could be found. No significant differences regarding the assessment of gender between the group of dentists and laymen were found (P>0.05; Mann-Whitney-Test adjusted by Bonferroni-Holm). Thus the two subgroups were pooled: Most of participants assigned the composite images “average female” (85.2%), “average male” (74.4%), “content female” (61.7%) and “content male” (61.7%) to female gender. The composite images “discontent female” (68.0%) and “discontent male” (75.0%) were assigned predominantly to male gender. The hit rate for correct assessment of gender referring to all composite images is about 50%. Conclusions: The images “discontent” showed esthetical deficiencies. No gender-specific characteristics could be found when evaluating composite images of upper front teeth.