Abstract
A method for measuring upper lip pressures in children was developed to evaluate the effects of myofunctional therapy. Five children with oral habits such as tongue thrust or abnormal swallowing performed functional exercises for the lips and perioral muscles over a period of more than three months. The upper lip pressures were measured before and after 1.5 and 3 months of therapy by a strain gauge pressure transducer placed on the labial surface of the upper central incisors. After placement of the transducer, the children were studied in both sitting and supine positions and the lip pressures were recorded at rest and swallowing in each position.
The average values of the resting lip pressures were 1.26g/cm2 (sitting) and 1.38g/cm2 (supine) before therapy and were 2.41g/cm2 (sitting) and 2.18g/cm2(supine) after three months of therapy. Analyses of the resting lip pressures and time-pressure integrals revealed that the resting lip pressures increased in four children after three months of therapy. All of the children performed the daily exercises satisfactorily, but one child who discontinued the exercises did not show a significant change in the resting lip pressure.
Average values of maximum lip pressures at swallowing were 3.1g/cm2 (sitting)and 2.6g/cm2 (supine) before therapy and were 8.6g/cm2 (sitting) and 7.8g/cm2 (supine) after three months of therapy. The maximum lip pressures increased markedly along with exercises. However, the waveforms of the lip pressures and the maximum pressure values differed considerably from each other in the swallowing trials.
The children who showed a tendency toward increased lip pressures prolonged the duration of the closed time of the mouth and had suitable tension in their lips. However, there seemed to be no change in their occlusion after three months of therapy.
