The influence of orthodontic treatment on esthetic perception of smiling face: an functional MRI study

Objective To explore the brain activation pattern when individuals judged attractiveness of faces before and after orthodontic treatment by using functional MRI (fMRI) . Methods Ninety-six beautiful/ugly faces before and after orthodontic treatment were used as stimuli. fMRI scans were acquired while 20 healthy subjects performed the facial attractiveness judgment. fMRI data was processed by SPM8 software. Results Facial attractiveness judgment was associated with greater activation in occipital lobe, temporal lobe and fusiform gyrus. For attractive people, the faces before orthodontic treatment compared to those after orthodontic treatment elicited significant difference in right mediate frontal gyrus, right middle frontal gyrus and right precentral gyrus. For unattractive people, the faces before orthodontic treatment compared to those after orthodontic treatment elicited significant difference in right paracentral lobule, right inferior parietal lobule, left middle temporal gyrus, bilateral cingulate gyrus and left precuneate gyrus. Conclusion Facial attractiveness judgment was associated with multiple brain regions. The faces before orthodontic treatment compared to those after orthodontic treatment elicited significant difference in the regions responsible for cognition, attention and emotion. Key words: Orthodontic treatment; Facial attractiveness judgment; Functional MRI