Perception of dental midline deviation and smile attractiveness by eye-tracking and aesthetic ratings

Abstract

Aim: To evaluate the perception of smile aesthetics and midline deviation considered by orthodontists (ORT), dentists (DT), patient’srelatives (PR), and laypersons (LP) using an eye-tracking device and survey. Methods: The study invited the participation of 42 orthodontists, 51 dentists, 50 patient-relatives, and 52 laypersons. A posed smile photograph of a female was chosen as a base image. The dental midline (DML) was digitally moved 1 mm (DML1R, DML1L), 2 mm (DML2R, DML2L), 3 mm (DML3R, DML3L), and 4 mm (DML4R, DML4L) on the base image’s right (DMLR) and left (DMLL) segments. Eight modified images were subsequently obtained. The base, modified, and repeated images were randomly arranged and uploaded into the Tobii Pro Lab software program for assessment by the participants. An eye-tracking dataset included first fixation duration (FFD), total fixation duration (TFD), and visit counts (VC). The participants also evaluated the photographs on the survey forms via a Visual Analogue Scale (VAS) and a Likert scale. The intra-group relations and inter-group correlations were evaluated statistically. Results: The TFD for the DML2R photograph was found to be statistically significant between the assessment groups (p = 0.026). While the longest fixation time (0.93 sec) belonged to the orthodontists, it was observed that the patient relatives had the shortest fixation time (0.51 sec). The VAS score for the DML2R image was found to be highest in laypersons (p < 0.001). In general, the survey scores of the patient relatives and laypersons were higher. Conclusion: The fixation time between the participant groups increased when there was a 2 mm deviation. A 2 mm shift in the DML was noticed by all participant groups and was considered unaesthetic.