Objectives: To determine an optimal anteroposterior (AP) position of the maxillary central incisors and their relationship to the forehead in adult African American (AA) females.
Materials and methods: Smile profile photographs of 150 AA females were acquired and divided into an optimal control group (N = 48) and a study group (N = 102) based on the position of the maxillary central incisors, as judged by a panel of orthodontists and orthodontic residents. The AP position of the maxillary central incisors and the forehead inclination (FI) were measured relative to Glabella vertical (GV). A two-sample t-test was used to compare the incisor AP position and the FI between the two groups. Linear regression was used to quantify the relationship between the incisor AP position and the FI.
Results: In all groups, the maxillary incisors were anterior to GV. However, a significant difference was found in the incisor AP position between the groups (8.58 ± 3.96 mm for the control group and 11.2 ± 4.48 mm for the study group; P = .001). Furthermore, the control group demonstrated a positive association between the optimal AP position of the maxillary central incisors and FI ( P < .0001).
Conclusions: GV is a reliable landmark with which to access the AP maxillary incisor position in AA females. The optimal AP position of the maxillary central incisors is significantly associated with FI; the greater the FI, the more anterior the optimal maxillary incisor position. A prediction equation to determine the optimal position of the maxillary incisors relative to GV for AA females is proposed.
Keywords: African American female; Forehead; Forehead inclination; Glabella vertical; Incisors; Landmark.