Written By : Dr. Rania AlRaddadi .
Here is a quick reminder & an illustration + some old but nonetheless classic references.
In ceph and photographic analysis there are many lines that have been introduced to assess lip position: Ricketts E line, Steiner’s S line, Holdaway’s H line, Burstone’s B line to name a few.. But actually the ones that are mostly used are the E line and the S line.
E-Line is drawn from Pronasale (Pn) to soft tissue pogonion (Pog) and lip prominence with reference to this line is assessed. Upper lip to E-Line =-1mm and Lower lip to E-line = 0 mm. This means that upper lip is slightly behind E-line & lower lip touches E-line in balanced face.
S-Line is drawn from midpoint between subnasale (Sn) and Pronasale (Pn) to soft tissue pogonion (Pog) and lip prominence with reference to this line is assessed. S-line though has been used cephalometrically but it has not been used on photograph to assess lip prominence. Its cephalometric norms are as follows: Upper lip to S Line (0±2mm), Lower lip to S Line (0±2mm).
Steiner used S-Line with the idea that E-Line is affected by nose length.
I attached a photo illustrating both lines.
Ricketts R.M. Esthetics, environment, and the law of lip relation. Am J of orthod 1968; 54: 272-289.
Steiner C.C. The use of cephalometric as an aid to planning and assessing orthodontic treatment. Am J of orthod 1960; 46: 721-35.
Holdaway R.A. A soft tissue cephalometric analysis and its use in orthodontic treatment planning. Part I. Am J of orthod 1983; 84(1): 1- 28.
Burstone C.J. Lip posture and its significance in treatment planning. Am J of orthod 1967; 53: 403-413.