Ideal mentolabial sulcus depth in long-face, short-face, and normal-face in female individuals.

Purpose: The harmony between the lips and the chin is an essential parameter in facial esthetics, and the mentolabial sulcus (MLS) represents the level of this harmony. This study aimed to assess the effect of MLS depth on facial profile attractiveness in long-face, short-face, and normal-face Iranian female individuals.

Methods: An observational study with a questionnaire was conducted, and a profile photograph of an Iranian female with class I occlusion was altered to create long-face, normal-face and short-face profiles with MLS depth ranging from 1 to 12 mm. Sixty-five lay people and 24 orthodontists rated the attractiveness of images using a 7-point Likert scale. Data were analyzed by independent t-test and Spearman's correlation coefficient using IBM SPSS Ver. 22.

Results: The ideal depth of MLS ranged from 5 to 7 mm for normal-face and short-faced and 6-8 mm for long-face Iranian females. The acceptable MLS depth was found to be up to 8 mm in normal-face and up to 10 mm in long-face and short-face females. normal-face images acquired the maximum score of attractiveness, followed by short-face images, while long-face images were the least attractive according to both observer groups. There was general agreement amongst orthodontists and lay people scoring process; however, orthodontists gave significantly higher scores for normal face images than lay people.

Conclusion: The optimal MLS depth in different facial types should be considered in treatment planning for orthognathic surgery and genioplasty.