Abstract
The therapeutic course of myofunctional exercises for the lips and perioral muscles, namely myofunctional therapy, was carried out over a period of more than three months for four children who had oral habits such as tongue thrusting or abnormal swallowing. The upper lip pressures both in resting and swallowing conditions were measured by a strain gauge pressure transducer placed on the labial surface of the upper central incisors before and 1.5 and 3 months after the initiation of the therapy. The strength of m. orbicularis oris was also measured by a spring balance. In addition, both values of the swallowing lip pressures and electromyograms of m. orbicuralis oris leading from surface electrodes were recorded synchronously. These synchronous data were then processed and analysed.
The average values of the resting lip pressure were 1.23g/cm2 (sitting) and 1.59g/cm2 (supine) before therapy and were 1.77g/cm2 (sitting) and 1.93g/cm2(supine) after 3 months of therapy. Analyses of the values of resting lip pressure and time-pressure integrals revealed that the resting pressure increased in three children after 3 months of therapy.
The average values of the maximum swallowing lip pressure were 4.35g/cm2(sitting) and 2.18g/cm2 (supine) before therapy and were 8.38g/cm2 (sitting) and 9.28g/cm2 (supine) after 3 months of therapy. The maximum lip pressure at swallowing increased during the course of the exercises in all four children. However, the waveforms of the lip pressure and the maximum pressure values differed considerably in each measurement with the swallowing trials. The same cases were found in our previous report.
The strength of m. orbicularis oris increased markedly during the course of the exercises.
There was scattering with the cross correlation of the active time between pressure and muscle activity in the course of swallowing in children, compared with normal adults. It was suggested that functional harmony of m. orbicularis oris and other perioral muscles in the course of swallowing in children was not formed sufficiently.
