Identifying three-dimensional facial fluctuating asymmetry in normal pediatric individuals: A panel assessment outcome study of clinicians and observers

This study measured three-dimensional facial fluctuating asymmetry in 600 normal and healthy Taiwanese individuals (6 to 12 years old) and assessed the perceptions of increasing levels of facial fluctuating asymmetric severity by using a panel composed of 20 clinicians (surgical professionals), as well as 20 adult and 40 pre-adolescent observers. On average, this normal cohort presented a facial fluctuating asymmetry of 0.96 ± 0.52 mm, with 0.52 ± 0.05, 0.67 ± 0.09, 1.01 ± 0.10, and 1.71 ± 0.36 mm for levels I, II, III, and IV of severity, respectively. For all categories of raters, significant differences in the average symmetry-asymmetry scale values were observed, with level I < level II < level III = level IV (all p < 0.01, except for level III vs. IV comparisons with p > 0.05). For level I, pre-adolescent observers presented a significantly (p < 0.05) higher symmetry-asymmetry scale value than adult observers, with no significant (all p > 0.05) differences for other comparisons. For overall facial asymmetry and levels II, III, and IV, no significant (all p > 0.05) differences were observed. This study reveals that the normal pediatric face is asymmetric and the panel assessment of facial fluctuating asymmetry was influenced by the level of severity and the category of raters and contributes to the literature by revealing that pre-adolescent raters present a similar or higher perception of facial asymmetry than adult raters.