The ideal face is divided vertically into equal thirds by horizontal lines adjacent to the hairline, the nasal base, and menton. The two other characteristics of the ideal lower third of the face are that the upper lip comprises the upper third and the lower lip and chin makes up the lower two thirds.
Increased Face Height
A vertical maxillary excess (VME) is a condition in which a patient has a long upper third and a long lower face with excessive gingival display on smile (often referred to as gummy smile) and an anterior open bite. The facial contour is characterized by a long, tapering face with anterior and posterior maxillary overgrowth, a narrow malar base, and lip incompetence.
Decreased Face Height
Short lower facial height can result from vertical maxillary deficiency (VMD), mandibular deficiency with diminished mandibular body or ramus height, or a short chin height. Facial characteristics of VMD are lack of upper incisor display (relaxed and smile lip), lack of lip separation, chin protrusion, and generally an older look at any age.
The analysis of the vertical thirds of the face is an initial gauge of the skeletal structures of the face and servers the clinician well by focusing on the face before the teeth, allowing observation of the gross proportionality of the face before the details are addressed