Summary: Ninety-two twelve-year-old subjects were examined for type of swallow and types and degrees of malocclusion. All were subjects who had been chosen at random eight years previously to participate in a longitudinal study of swallowing. Four years had lapsed since the children had been evaluated. Purposes were: (1) to determine incidence of tongue thrust, and (2) to examine relationships between malocclusion and tongue thrust. The incidence of tongue thrust was found to be 48.9%. This was considerably higher than had been expected. It is probable that ten of the 45 with a tongue thrust were transitional thrusters. If these ten were excluded, the incidence would be 38.9%. A chi square formula was used to determine possible relationships between various types and degrees of malocclusions and manner of swallowing. No significant relationships were found. However, all but one of the subjects with overjets of 5mm. or more were tongue thrusters.
Hanson, T. E., & Hanson, M. L. (1975). A follow-up study of a longitudinal research on malocclusions and tongue thrust, International Journal of Oral Myology, 1 (1), 21-28.