Pressure from the lips and the tongue in children with class III malocclusion

Abstract

Abstract:Objective: To discuss possible relationships between class III malocclusion and perioral forces by measuring the pressure from the lips and the tongue of children with class III malocclusion. Methods: Thirty-one children with class III malocclusion were investigated and their perioral forces were measured at rest and during swallowing under natural head position by a custom-made miniperioral force computer measuring system. Results: The resting pressures exerted on the labial side and palatine side of the upper left incisor, as well as the labial side and lingual side of the lower left incisor, were 0 g/cm 2 , 0 g/cm 2 , 0.57 g/cm 2 and 0.23 g/cm 2 , respectively. Correspondingly, the swallowing forces were 2.87 g/cm 2 , 5.97 g/cm 2 , 4.09 g/cm 2 and 7.89 g/cm 2 , respectively. No statistical difference between muscular pressure and gender existed. During swallowing, the lingual forces were significantly higher than the labial forces (P<0.01), however, at rest there was no significantly different force between these two sides. Compared to the normal occlusion patients, children with class III malocclusion had lower perioral forces. The upper labial resting forces (P<0.01), the lower labial resting forces (P<0.05) and all the swallowing pressures from the lips and the tongue (P<0.01) showed statistical differences between the two different occlusion conditions. Meanwhile, no significant difference was found for the resting pressure from the tongue between class III malocclusion and normal occlusion. Conclusion: Patients with class III malocclusion have lower perioral forces and this muscle hypofunction may be secondary to the spatial relations of the jaws. The findings support the spatial matrix hypothesis.

The time-course change in the lip closing force in Class III malocclusion after orthognathic surgery

“…This finding was similar to that of the previous study of Ruan et al (2007). This suggested that the maximum lip closing force of Class III patients is weaker in both adults and children.…”

“…Lambrechts et al (2010) found that the maximum lip pressure in Class II division 1 was lower than that in Class I, but there were no significant differences in the other comparisons (Class I, Class II division 1, Class II division 2 and Class III). Ruan et al (2007) showed that paediatric patients (4e6 years old) with a Class III malocclusion generated lower perioral muscle forces. This may cause less bone apposition in this area, which aggravates the clinical features of Class III malocclusion.…”

“…Posen (1976) found that subjects with bimaxillary protrusion have low lip strength, compared with Class I and Class II Division 2 patients, using a device for measuring the strength of the lips. Ruan et al (2007) reported that patients aged 4e6 years with Class III malocclusion had lower perioral forces and this muscle hypofunction might be secondary to the spatial relation of the jaws.…”

Changes in the lip closing force of patients with Class III malocclusion before and after orthognathic surgery

“…5,14,15 Posen 15 found that the subjects with bimaxillary protrusion had low lip strength, compared with Class I and Class II Division 2 patients, using a device for measuring the strength of the lips. Ruan et al 20 reported that patients aged 4 to 6 years with Class III malocclusion had lower perioral forces and this muscle hypofunction might be secondary to the spatial relation of the jaws.…”

Development and Clinical Application of Instruments to Measure Orofacial Structures

“…When using this instrument, great attention should be given to controlling the action of compensatory muscles, such as the mentalis. Other assessing instruments reported in the literature use force or pressure lip sensors attached to the teeth (Gentil and Tournier 1998;McHenry et al 1999;Ruan et al 2007). These electrodes are fixed by special glues or dental adhesive.…”