This study aimed to assess the relationship of the anteroposterior position of maxillary central incisors with the forehead in an Iranian subpopulation residing in Kermanshah city.

In this cross-sectional study, 12 orthodontists were requested to analyse full-smile profile photographs with complete maxillary incisor and forehead show in 70 patients with optimal facial harmony (35 males and 35 females) as the control group and 140 patients without optimal facial harmony (70 males and 70 females) as the test group. The inclusion criteria were (I) males and females between 18–60 years seeking orthodontic treatment and (II) willingness for participation in the study. The exclusion criteria were (I) presence of severe craniofacial anomalies, and (II) history of orthodontic treatment. The photographs were traced and analysed using Digimizer Image Analysis software 5.3.5. Data were analysed using STATA version 14.2 via independent t-test and linear regression.

A significant difference existed in the anteroposterior position of maxillary incisors in males between the test and control groups (P=0.002). However, this difference was not significant in females of the two groups (P=0.77). A significant difference was noted in the anteroposterior position of maxillary incisors between males and females in the test group (P=0.001) but not in the control group (P=0.80). The frontal angle had a significant correlation with gender and anteroposterior position of maxillary incisors in both groups (P<0.001).

According to the results, the anteroposterior position of maxillary incisors was significantly different in the test and control groups. The maxillary incisors in males were more retruded than in females. Also, the frontal angle had a significant correlation with the anteroposterior position of maxillary incisors, and by 1° increase in the frontal angle, the incisors were protruded by averagely 0.307mm.