Resting tongue pressures.

A specially-designed force transducer was used to measure lateral resting-tongue pressure in 23 subjects. Seventeen subjects had normal occlusion and six had dental open-bite conditions. Three sensing tips with different contact areas were used to study the relationship between sensor area and measured force. The average force of the resting tongue was 0.8 g when measured with a 4.9 mm diameter sensor (pressure = 0.039 g/mm2). When the size of the sensor tip was increased, the force of the tongue increased in a nonlinear manner. Controlled incremental lingual constrictions of 6 mm resulted in an average increase in lingual force of 230 percent. The mean rate of change, measured in deflection gradient, was 0.34 g/mm. The mean stiffness of the lingual musculature was 2.30 g/mm. A correlation of r = --0.4 was found between resting-tongue pressure and mandibular intercanine width.