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

Sümeyye Aşik,Hatice Kök

doi:10.21307/aoj-2021.020

Abstract

Abstract Aim To evaluate the perception of smile aesthetics and midline deviation considered by orthodontists (ORT), dentists (DT), patient’s-relatives (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.

Highlights

Smile aesthetics are influ enced by oral components which are identified as smile arcs, buccal corridors, the smile line, upper lip curve, smile symmetry, occlusal cant, dental alignment, and gingival morphology.[2]
In order to achieve an ideal cosmetic result, identifiable reference parameters should be considered as aesthetics remains a subjective concept which can vary between individuals and cultures.[3]
Aesthetic perception varies between people and can be influenced by gender, personal experience, and social environment

Summary

Introduction

Smile characteristics require detailed consideration during treatment planning to make an orthodontic result more acceptable.[1,2,3] Smile aesthetics are influ enced by oral components which are identified as smile arcs, buccal corridors, the smile line, upper lip curve, smile symmetry, occlusal cant, dental alignment, and gingival morphology.[2] In order to achieve an ideal cosmetic result, identifiable reference parameters should be considered as aesthetics remains a subjective concept which can vary between individuals and cultures.[3] Previous research has reported aesthetic perception studies using various evaluation scales to assess smile components. These systems are used in medical and para-medical fields, they have been recently incorporated into orthodontic research.[23,24,25,26,27] Using eye tracking, Hickman et al.[23]

Objectives

Methods

Results

Discussion

Conclusion