The Orthodontics Professors
the latest in contemporary & evidence-based orthodontics
BY DAVID M. SARVER, DMD, MS
An eye-tracking study from The Ohio State University published in the AJO-DO provides clinicians new data to help them understand how smile esthetics interact with overall facial esthetics.
In the study, faces of varying attractiveness (“attractive”, “average”, or “unattractive”) were paired with dentitions that reflected malocclusions with a dental attractiveness ranging from 3-7 on the IOTN-AC scale. In this way, attractive faces could be paired with unattractive teeth, for example.
66 lay persons viewed 15 different combinations of faces with the teeth visible only within the framework of the smile. All of the faces were those of Caucasian women, and all participants were 18 - 30 year old Caucasians, in an effort to control for any possible other-race or age effects in terms of perception.
Objective eye-tracking hardware and software was used to evaluate what parts of the face participants spent the most time viewing during a 3 second exposure to each face. Interestingly, participants were not told that the purpose of the study was to evaluate dental or facial esthetics until after their participation.
Both eye fixation duration (time spent looking at one part of the face) and eye fixation density (how many times one part of the face was viewed) differed depending on the attractiveness of the face, the attractiveness of the dentition, the region of the face, and the gender of the participant.
For all the participants, more attention was focused on the mouth as the dentition became more unattractive.
For female participants, a significantly greater density and duration of gaze was focused on the mouth with the combination of an attractive face paired with an unattractive smile.
WHAT THE PROFESSOR THINKS
The study design is appropriate and used validated techniques that generate objective data for the very subjective field of facial esthetics. Using a specific age and ethnicity demographic, as well as an age, gender, and race restricted set of faces as stimuli is appropriate since it helps to control for some well-established potential confounders of judging facial attractiveness.
Finally, deceiving participants as to the nature of the eye-tracking task was clever. In this way, participants were not biased. Instead, these eye tracking data represent the “unconscious” judgement of facial attractiveness, which is ultimately the way most of our patients are judged most often after treatment.
This study has some interesting implications for the clinician who is interested in the very best communication with patients when it comes to the complicated topic of facial and dental esthetics:
Article Reviewed: Johnson EK et al. Role of facial attractiveness in patients with slight-to-borderline treatment need according to the Aesthetic Component of the Index of Orthodontic Treatment Need as judged by eye tracking. Am J Orthod Dentofacial Orthop. 2017; 151 (2) 297-310.
Reference: Sarver DM. Enameloplasty and Esthetic Finishing in Orthodontics—Identification and Treatment of Microesthetic Features in Orthodontics Part 1. J Esthet Restor Dent. 2011; 23 296-302.
Tate H. Jackson, DDS, MS