Quantitative investigation of the esthetic impact of lip prominence in relation to the esthetic line

Introduction The purpose of this quantitative investigation was to assess the influence of lip prominence in relation to the esthetic line (E-line) on perceived attractiveness and threshold values of desire for treatment. Methods The lip prominence of an idealized silhouette male white profile image was altered incrementally between -16 mm to 4 mm from the E-line. The images were rated on a Likert scale by pretreatment orthognathic patients (n = 75), laypeople (n = 75), and clinicians (n = 35). Results In terms of perceived attractiveness, lips to E-line distance within the ranges of -12 mm to -16 mm and 0-4 mm in relation to the E-line was associated with a reduction in median attractiveness scores to below 4 in the patient and clinician groups of observers; for the lay group, the corresponding ranges were -14 mm to -16 mm and 2-4 mm. Relative lip prominence appears to be viewed as more attractive than lip retrusion. Clinicians were generally least likely to suggest treatment for varying levels of bilabial position. For a number of the images, there was reasonable agreement among clinicians and laypeople regarding whether treatment is required. For the clinician group, the only categories for desire for treatment were at a lip to E-line distance within the ranges of -14 mm to -16 mm and 2-4 mm. Conclusions It is recommended that the range of normal variability of the prominence of the lips and threshold values of the desire for treatment be considered in planning.