Influence of orthodontic appliances on visual attention to smiling faces by eye-tracking evaluation

The influence of wearing orthodontic appliances on visual attention to smiling faces is not well understood. The purpose of this study was to investigate how laypeople viewed a frontal posed smiling face with orthodontic appliances compared with orthodontists. Frontal posed smiling facial photographs of 10 female models without an appliance or wearing clear tray, ceramic, or metal appliances were taken, and areas of interest (AOIs) for the eyes, nose, and mouth were determined. Visual attention from 43 laypeople and 42 orthodontists was evaluated for each image using an eye-tracking system. Total fixation time for each AOI was calculated and analyzed by three-way repeated measures analysis of variance and Tukey–Kramer multiple comparison tests (P < 0.05). The layperson group spent significantly more time looking at the mouth with ceramic and metal brackets than without brackets, similar to the orthodontist group (P < 0.001 and 0.001, respectively). Though the orthodontist group spent significantly more time looking at the mouth with metal brackets than the mouth with ceramic brackets (P < 0.040), no significant difference was noted in the layperson group. Under all appliance conditions, the layperson group spent significantly more and less time looking at the eyes and mouth than the orthodontist group, respectively (P < 0.001 and 0.001, respectively). These findings suggest that it may help patients who will start orthodontic treatment to understand an individual’s interest in the appearance of the orthodontic appliance, and orthodontists to counsel patients at the orthodontic appliance selection stage during the diagnosis.