Lip and tongue pressure in orthodontic patients.

SUMMARY The contribution of the force of the lips, cheeks, and tongue is of particular interest in planning treatment. Thus, the aim of this study was to determine if there are differences in lip and tongue pressure as a function of gender, age, Angle classification, characteristics of occlusion, and oral habits. This cross-sectional study comprised 107 subjects (63 females and 44 males), between 7 and 45 years of age (median 15.2 years), seeking orthodontic treatment. The patients were characterized by the variables gender, age, Angle classification, the characteristics of the occlusion, and oral habits. Lip and tongue pressure were measured with a Myometer 160 and the obtained values were statistically analysed (Kruskal-Wallis and Mann-Whitney U-tests) to highlight possible significant differences between the groups. There was a difference in lip pressure between males and females, between the Angle Classes, and between patients with various associated oral habits. Lip pressure was not significantly correlated with age or with occlusal characteristics. There was no evidence for a relationship between tongue pressure and any of the five considered variables. The findings of present study showed statistically significant differences in lip pressure between different orthodontic patients. There was a difference (P = 0.004) in lip pressure between Class I and Class II division 1 subjects. A higher lip pressure exists in males. Lip pressure in subjects with an open lip relationship was lower (P = 0.026) when compared with those with tongue interposition or with no particular habits. Lip pressure was also lower in subjects with lip interposition compared with those with tongue interposition.