Purpose : The purpose of the present study was to examine the relationship of tongue pressure and changes in occlusal vertical dimension to swallowing.
Materials and Methods : The volunteer subjects were four young male dentulous adults and eight elderly complete denture wearers. The tongue pressure to the palate was simultaneously recorded with electromyography (EMG) measurements of the suprahyoid muscles as the occlusal vertical dimension changed. The subjects were instructed to perform two actions : swallowing without any liquid or food (dry swallowing) and swallowing of 2 ml water (wet swallowing).
Results : During dry swallowing, the maximum pressure decreased significantly as the vertical dimension increased in the young subjects. In the elderly, the maximum tongue pressure decreased monotonically as the vertical occlusion increased. The same results were clearly found for wet swallowing. Overall data suggested that the tongue pressure of the elderly group was lower and the duration of tongue pressure in wet swallowing was longer than that of the younger group.
Conclusion : An increase of the vertical dimension decreased the tongue pressure to the palate, whereas a decrease of the vertical dimension affected the tongue pressure less. Tongue pressure is an important factor for the evaluation of tongue function, especially swallowing.