To explore whether the facial reference lines is suitable for evaluating the facial profile attractiveness of the orthodontic patients.

This study included 80 posttreatment skeletal Class I patients (60 females and 20 males). Post-treatment lateral photographs were collected and subjectively scored by 10 experienced orthodontists. Moreover, the cephalograms were collected and cephalometric measurements related to upper central incisors were performed. In addition, the cephalograms were superimposed with the photographs to determine the distance of the maxillary incisors to FALL line (FA-FALL) and GALL line (FA-GALL). Pearson correlation analysis was conducted to explore the correlation between objective central incisor and soft tissue profile measurements and subjective evaluations.

For the linear measurements of upper central incisors, FA-FALL was negatively correlated with the total VAS score and the VAS score of each part of the face. Moreover, U1-APo angle was negatively correlated with the total VAS score and the VAS score of the upper and lower lips and the chin. In addition, FA-FALL is strongly correlated with forehead inclination (P<0.001), moderately correlated with H angle (P<0.001) and weakly correlated with NLA, the upper lip to E-line distance, and MLA (P=0.004, P=0.002, P=0.048). FA-GALL has no significant correlations with the soft tissue measurement indexes, except showed weak correlation with FNA(P=0.025).

The distance between maxillary central incisors and the facial reference line FALL line can be used to evaluate the profile attractiveness of orthodontic patients.

Profile evaluation; Forehead's anterior limit line; Goal anterior limit line; Maxillary incisor