Optimal Anteroposterior Position of Maxillary Incisors in Caucasian Males Viewed from a Smiling Profile

Abstract

Background and Objectives: Anteroposterior (AP) position of the maxillary incisors affects the harmony of a facial profile. Different methods have been suggested to evaluate the maxillary incisor AP position, including cephalometric analysis and softtissue analysis. Andrews suggested using a lateral smiling profile to evaluate the AP position of the maxillary incisors. The objective of this study was to investigate the optimal AP position of maxillary incisors in Caucasian males using Glabella Vertical (GV), a coronal plane tangent to soft tissue Glabella, as a reference line. In addition, an attempt was made to determine if there are differences in judged facial attractiveness between smiling versus repose profiles, and between dental professionals versus laypersons, and males versus females. Experimental Design and Methods: Smiling and repose profile photographs of 30 randomly selected Caucasian adult males were taken in adjusted natural head position. The AP distance between the maxillary central incisors and GV was measured for each subject. A total of 36 judges (6 male orthodontists, 6 female orthodontists, 12 male lay judges, and 12 female lay judges) were recruited to rate the facial attractiveness of each subject's photograph using a visual analog scale. The data was examined using Tukey's test for multiple comparisons, ANOVA, and chi-square analysis. Results: No statistically significant difference was found in judged facial attractiveness among Caucasian males with various AP positions of maxillary incisors. However, a trend was found; incisors falling on GV were preferred by the judges, followed by incisors ahead of the GV, with incisors behind GV being the least preferred. A significant difference in facial attractiveness was found between smiling versus repose profiles, in particular, patients with maxillary incisors behind GV being judged less attractive. Orthodontic training and sex of the judges did not significantly affect the judgment of facial attractiveness. Conclusions: The AP position of maxillary incisors in Caucasian males might not be a significant factor defining face attractiveness. However, there is a tendency for the preferred maxillary incisor position to fall on GV, ahead of GV being less preferred, and behind GV being least preferred. Orthodontic training and gender does not affect perception of profile esthetics. A smiling profile view is useful for assessing facial esthetics. AKNOWLEDGEMENTS I would like to acknowledge the support and assistance I have received during this project and throughout my orthodontic residency. My sincere appreciation to the following individuals: Dr. Peter Ngan: Thank you for serving as my thesis advisor and chair of my committee. You have been a wonderful chairman, teacher, and mentor. I owe you a great debt of gratitude for allowing my dream to become true. Dr. Tim Tremont: Thank you for providing an unbelievable foundation for my future orthodontic career. You have provided invaluable guidance on this project. Dr. Chris Martin: Thank you for serving...