Posen A L
Angle Orthod. 1976 Apr;46(2):118-43. doi: 10.1043/0003-3219(1976)046<0118:TAOQPA>2.0.CO;2.
Maximum tonicity of the lips can be accurately measured through the use of the pommeter. 2. Patients with significant hypertonicity of the lips whose maxillary central incisors are positioned oingualy as in Class II, Div. 2 and also in certain Class I malocclusions should be treated nonextraction and as early as possible. Torguing maxillary incisors into a more normal labial axial inclination is a form of expansion which does not detrimentally affect the position and function of the perioral muscles. In this early conservative approach not only is arch length increased but also marked improvement in the overbite is accomplished. These types of treated malocclusions should be retained until after the eruption of the second permanent molars. 3. If extraction is necessary in patients with hypertonic lip muscles it should be done as far as possible from the incisor teeth, preferably the second premolars. 4. In Class I malocclusions where maximum tonicity is in the normal range is to attempt to accommodate blocked out or rotated teeth within the framework of the perioral musculature surrounding the teeth...