A SIZE-STANDARDIZED ANALYSIS OF SOFT-TISSUE FACIAL PROFILE DURING GROWTH

A method for the quantitative and qualitative analysis of the facial s oft tissue profile has been developed and applied to analyze the age d ifferences in lateral cephalograms for the annual Bolton standards fro m ages 1 to 18 years. To standardize for different facial sizes, profi les were traced in polar coordinates without modifications of facial s hape. Most of the soft tissue landmarks showed progressive modificatio ns from birth to 18 years of age. Soft tissue nasion and lower lip had a steep change between 2 and 3 years of life, pronasale between 3 and 5 years of life, A', upper lip, and stomion between 4 and 5 years of life. Hereafter, all these landmarks but N' had several minor modifica tions progressing toward the adult value. Soft tissue nasion did not m odify significantly after 2 years of age. Conversely, changes in the r elative positions of B' and Pg' were more scattered in the analyzed pe riod. Age-related size differences were more linear than shape modific ations, with gradual increments from 1 to 18 years of age. The method allowed a simple and rapid quantitative evaluation of soft tissue prof iles during facial growth. An approximate evaluation of the soft tissu e thickness at nose, lips, and chin was also possible. No particular m athematical knowledge was required at any step of the analysis. Result s were in good agreement with the well-known patterns of normal growth and development, thus confirming the practical possibilities of the m ethod.