Maximum lip closure pressure in growing children

Abstract

We measured the maximum lip closure pressure of 295 elementary school children using a lip pressure gauge. The mean value and standard deviation were calculated for each grade. In addition, the same measurements were made for 36 elementary school children longitudinally from the second through the sixth grades.
     The mean values and standard deviations of maximum lip closure pressure for the children in the first through sixth grades were 2.5±15 N, 3.1±1.9 N, 47±2.3 N, 4.8±3.1 N, 7.0±3.3 N, and 7.9±4.2 N, respectively. For the longitudinal measurements, the figures were 2.9±3.1 N, 3.1±3.4 N, 4.8±3.1 N, 9.5±3.1 N, and 10.1±3.1 N, for the second through sixth grades.
     The results showed a gradual increase in the lip closure pressure with age, with the qreatest change seen between the fourth and fifth grades. These results suggest that the functional forces of the orbicularis oris muscle change during growth.