Background: Smile esthetics have been shown to play a major role in the perception of whether a person is attractive, and whether they are perceived as friendly, trustworthy, intelligent, and self-confident. A proposed major determinant of the esthetics of a smile is the amount of gingival display, which can be excessive in cases of altered passive eruption. The aim of this study is to see whether altering the amount of gingival display of patients would affect dental professionals' and laypersons' perceptions of the aforementioned social parameters.
Methods: Patients were identified as having altered passive eruption and excessive gingival display. Smiling "control" photographs were taken and then digitally altered so as to lengthen the teeth and thus reduce the amount of gingival display. These became the "test" photographs. The control and test photographs were shown in random order. The control group of evaluators consisted of senior dental students, and the test group of evaluators comprised students who had no formal dental training. Groups were asked to rate, on a visual analog scale, each picture's attractiveness, friendliness, trustworthiness, intelligence, and self-confidence.
Results: The test pictures with less gingival display were consistently and statistically significantly rated higher for all five social parameters than were their control counterparts (P <0.0001). When analyzed as an isolated effect, there were no statistically significant differences between the control group and the test group of evaluators when rating the pictures. Pictures depicting African Americans were judged to be more trustworthy (P = 0.0467) and self-confident (P = 0.0490) than pictures depicting white individuals. Pictures depicting women were judged to be more trustworthy (P = 0.0159) and intelligent (P = 0.0329) than pictures depicting men. All the social parameters were positively and statistically significantly correlated with each other (P <0.0001).
Conclusions: Excessive gingival display did negatively affect how attractive a person's smile is judged to be. In addition, how friendly, trustworthy, intelligent, and self-confident a person was perceived to be was inversely related to the amount of gingival display. Untrained laypeople were just as sensitive to these differences as senior dental students.