Laypeople's and dental students' perceptions of a diastema between central and lateral incisors: Evaluation using scanpaths and colour-coded maps.

Abstract

This study aimed to use eye tracking to analyse people's visual perceptions of smiles with a diastema between the maxillary central and lateral incisors, based on different categories of observers. An image of a diastema between the maxillary central and lateral incisors was shown to dental students and laypeople. Our null hypothesis was that there would be no difference in the visual perception of the different graduations of diastemas between the two groups. The diastemas were edited in Photoshop® to gradually increase the distance between the maxillary central and lateral incisors from no diastema to 1.5mm and 3.5mm diastemas. These diastemas were evaluated by using a TheEyeTribe© tracker in conjunction with OGAMA© 5.0 software. A total of 37 dental students and 33 laypeople looked at eight randomly arranged images of smiles. The data were analyzed using color coded maps, scanpaths, and the Kruskal-Wallis test with a level of significance of 5%. Laypeople tended to observe the eyes, focusing more on the right than the left, and spent less time focusing on the diastema region than did the dental students. There were differences for the same magnitude of diastema within participant groups. As the width of the diastema increased, both students and laypeople focused more on the diastema region. The two groups of evaluators presented different perceptions of smiles in cases of diastema between the maxillary central and lateral incisors when evaluated using eye-tracking.