Further studies of the pressure from the tongue on the teeth in young adults.

The pressures from the tongue on the teeth were recorded simultaneously in four locations lingual to the upper and lower central incisors, and left first molars in 20 young adults with largely normal occlusion. Measurements in the rest position, and during chewing and swallowing were made with an extra-oral pressure transducer incorporated in a fluid-filled system with intra-oral mouthpieces. The size of the dental arches was determined from dental casts. The median pressures in the rest position were low and negative at the upper incisors. Negative pressures at rest were recorded in a few subjects at all four points of measurement, most frequently at the upper incisors and least frequently at the lower molar. The pressures during swallowing were 2-4 times greater than those during chewing. There were no significant correlations between the pressures found and those recorded in the same individuals at an examination 2 years earlier. Positive correlations were found between the pressures recorded in the four locations during the various functions. This was interpreted as being an effect of the size of the tongue. The relatively few correlations between the pressures and the parameters describing the dental arch size indicated an adaptive role of the tongue within the confines of the dental arches.