Soft tissue facial growth and development as assessed by the three-dimensional computerized mesh diagram analysis

The normal growth and development of facial soft tissues from 6 years to ad ulthood has been studied by the 3D computerized mesh diagram analysis. The analysis allows independent quantifications of size and shape modifications both between different age groups, and between males and females. Normal a ge-related and sex-related references are provided. The three-dimensional f acial morphometry method has been used for the collection of the x, y, z co ordinates of 22 soft tissue landmarks in 2023 examinations performed on 115 7 healthy white children and adolescents between 6 and 17 years of age and 191 young adults. The method detects the three-dimensional coordinates of r etroreflective, wireless markers positioned on selected facial landmarks us ing two charge-coupled device cameras working in the infrared field. For ea ch sex and age class, mean values were computed, and a standardized mesh of equidistant horizontal, vertical, and anteroposterior lines was consequent ly constructed. Within each age group, male meshes were superimposed on fem ale meshes. Moreover, within each sex, the adult reference mesh was superim posed on the reference mesh of each age group. The global (size plus shape) difference was then evaluated by the calculation of the relevant displacem ent vectors for each soft tissue landmark. A global difference factor was c alculated as the sum of the modules of all the displacement vectors. Conseq uently, a size normalization was performed, and the shape difference (size standardized) was then evaluated by the calculation of new relevant displac ement vectors for each landmark, as well as a shape-global difference facto r. When compared to the young adult situation, the largest child discrepanc ies were found in the soft tissue profile. After size standardization, shap e differences were found in the forehead, nose, and chin. The soft tissue f acial dimensions of boys and girls grow with similar characteristics and at the same rate between 6 and 11 years of age, but showed different patterns after this age. Within each age class, most of the sex-related differences were dimensional discrepancies that were corrected after size standardizat ion. Nevertheless, before adolescence even these size differences were limi ted. On average, male faces had a larger forehead, longer and more vertical nose, more inferior and posterior gonia, more inferior and prominent lips, and a larger mouth than female faces of corresponding age.