Three-dimensional mixed longitudinal study of facial growth changes and variability of facial form in preschool children using stereophotogrammetry.

Objectives Since the normal, non-pathological facial growth in preschool children is not sufficiently reported, the aim was to follow growth changes of facial surface, sex differences and facial variability in preschool children using 3D stereophotogrammetry. Settings and sample population Mixed longitudinal sample of healthy Caucasian preschool children without head and facial trauma or craniofacial anomalies from 3.4 to 6.7 years of age consisted of 25 girls and 17 boys. Materials and methods 136 3D facial models from optical scanner Vectra 3D were evaluated by geometric morphometrics (CPC-DCA, PCA, per-vertex t test). Results In both sexes, the lower face was widened and elongated, and the prominences of the superciliary arches, lower orbital region, nose, lips and chin increased. Facial surface increments were more even in girls with a maximum between the fourth and fifth year of age, while in boys, there was the most intensive growth between fifth and sixth year of age. Sexual dimorphism was very stable during investigated period, only less statistically significant at the age of 3 years. Boys had more prominent lateral lower part of forehead, nose and lips than girls in every age category. Conclusions The longitudinal growth of the face between third and sixth year of age was similar in both sexes, facial sex differences were found in terms of intensity, size and timing. Variability of facial form showed that boys' faces were larger on average and facial shape did not differ. The knowledge of facial growth is essential for diagnostics and clinical practice.