Method: Forty adult Caucasian subjects (20 male, 20 female) participated as models in the study. Two traditional orthodontic extra-oral photographs were taken of each model: full face at rest and full face smiling. A survey was conducted to determine the ten most attractive male and female faces. The original photographs of these faces were edited and used in the final computer-based survey. Adobe Photoshop® was used for colour correction, lighting adjustments, and cropping to standardized sizes corresponding to best practice. Three edited photographs were created for each model: full face at rest, full face smiling, and smile only. Non-dental undergraduate students (n=123) and dental undergraduate students (n=50) served as image evaluators.
Result: The average ratings of attractiveness were highest for the 'full face smiling' images, and this difference achieved statistical significance (p<0.05). Since attractiveness ratings were lowest for the 'smile only' images, the presence of a smile appears to improve perceived attractiveness regardless of dental aesthetics. A significant difference exists between the average ratings for hair colour and dental education (non-dental vs. dental undergraduate students). Evaluator ethnicity did not influence ratings.
Conclusion: The presence of a smile improved perceived attractiveness ratings, regardless of dental aesthetics. While hair colour did have an impact on attractiveness ratings, the sample size was too small to allow for in-depth analysis, and further investigation is needed on this variable. Dental undergraduate students, on average, were more critical of facial aesthetics than their non-dental counterparts.