Effect of Denture Base Shape on Swallowing Pressure

Abstract

In clinical practice maxillary dentures are often designed to assume a form analogous to the patient's palatal morphology, with little attention paid as to how the design affects masticatory function. However, because many denture users are elderly, it is necessary to consider how age reduces masticatory function when designing the form of the palatal part of the denture. Denture morphology should be designed to facilitate the generation of the inner pressure needed for mastication. Therefore, we simultaneously measured the pressure in the oral cavity and the pharynx during mastication using three types of palatal bases. The palatal base was designed (1) with uniform base thickness, (2) with the base thick in the region anterior to the distal aspect of the bilateral maxillary canines, which emphasized contact with the lingual apex, or (3) with the base thick in the posterolateral region on both sides of the palate, which emphasized contact with the dorsal aspect of the tongue. The use of the latter base shortens the time needed for passage of the bolus through the oral cavity and pharynx. We also found that the pressure level and integrated pressure not only within the oral cavity but also in the middle pharynx can vary depending on the morphology of the base in the palatal region. These results suggest that when healthy individuals swallow water, the increase in contact pressure between the palate and the back of the tongue, which is dependant on base morphology, activates the muscles that coordinate with each other in swallowing. This in turn affects the pressure within the oral cavity and at the middle pharynx, as well as the time needed for passage through the oral cavity and pharynx.