The influence of lip function on the sagittal and transversal development of the maxilla in cleft patients.

Cleft patients who have undergone surgery often show considerable inhibition in the sagittal development of the mid-face after completed growth. This is partly attributed to scar contraction in the lip region following surgery. The present investigation deals with the etiological factors involved in the development disturbances caused by the cleft in the maxilla of 100 cleft patients. Particular attention was paid as to the unfavourable effect of the operated cleft lip. This was tested electromyographically and correlation between the electromyographic and the skeletal measurements was sought. Electromyographic changes in lip activity during orthodontic treatment was also investigated. The effect of these changes is discussed.