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.