RESUMO
INTRODUCTION: The purposes of this study were to measure the 3-dimensional parameters of the posed smile and to see whether there are any correlations with vertical cephalometric skeletal measurements. METHODS: Pretreatment records from a sample of 110 white girls between the ages of 12 and 18 years were gathered. The measurements of SN-GoGn, anterior facial height, and lower and upper facial height percentages were obtained from tracing lateral cephalograms. Superimposing the repose and the posed smile facial scans allowed for measurements to be obtained showing the movements in the x, y, and z dimensions of the upper and lower lips, the commissures, and the Cupid's bows. Correlations and multiple linear regression analyses were run to check for associations and predictive relationships between the cephalometric skeletal measurements and soft tissue changes. RESULTS: We found significant moderate correlations and weak correlations. Significant multiple regression models were found for intercommissural width, smile index, and lower lip in the y and z dimensions. CONCLUSIONS: There were moderate correlations showing that as SN-GoGn and anterior facial height increased, the interlabial gap increased as the smile index decreased. Significant relationships were found between certain hard tissue cephalometric measurements and the width of the smile as well as the movements of the lower lip.