Relationship of Various Anatomic Landmarks with the Midline of Face and Oral Commissure

Abstract

Introduction: Currently, there are no exact guidelines which to choose specific anatomic landmarks while determining the midline of the face or midline of the mouth. The purpose of this study was to determine the hierarchy of facial anatomic landmarks closest to the midline of the face as well as midline of the oral commissure mouth.

Methods: Anatomical landmarks Nasion, tip of the nose, and tip of the philtrum, were marked clinically on 100 subjects (age range: 20-35 years). Frontal full-face digital images of the subjects in smiling position were then made under standardized conditions. A total of 97 subjects met the inclusion criteria. Upon applying exclusion criteria, images of 73 subjects were used for midline analysis using a concept called the Esthetic Frame. One sample t tests were conducted at alpha values of .005.

Results: The results indicated that anatomic landmarks soft tissue nasion, tip of nose, tip of papillae and dental midline deviated uniquely and significantly (P <.005) from the midlines of the face as well as the mouth (oral commissure).

Conclusions: Within the limitations of the study, the hierarchy of anatomic landmarks closest to the midline of the face in smile was as follows: the midline of the oral commissures, natural dental midline, tip of philtrum, nasion, and tip of the nose. The hierarchy of anatomic landmarks closest to the midline of the oral commissures was: natural dental midline, tip of philtrum, nasion and tip of nose.