Steyn C L
Am J Orthod. 1981 Jan;79(1):81-5. doi: 10.1016/0002-9416(81)90103-2.
In the construction of a visual treatment objective, prediction of the changes in lip morphology is of great importance. A major factor is the vertical position of the embrasure and its relation to the incisal edges of the upper incisors. An aid to the problem of incompetent lips is hereby suggested.