Why might a patient have difficulty swallowing with complete dentures?

A patient may have difficulty swallowing with complete dentures primarily due to insufficient interocclusal space. When the space between the upper and lower jaws is not adequately accounted for in the design of the dentures, it can restrict the movement necessary for proper swallowing. This limited space can make it challenging for the patient to position food correctly in their mouth, which is crucial for swallowing.

Effective eating and swallowing rely on an optimal relationship of the upper and lower jaws. If the dentures are designed without taking this interocclusal space into consideration, it can lead to discomfort and an inability to swallow efficiently. This can particularly impact new denture wearers who may not yet have adapted to the presence of the dentures in their mouths.

The other options do not specifically address the biomechanical interplay between the lower and upper jaws that is key to swallowing. While inappropriate sizing, material allergies, or alignment issues can affect comfort and function, insufficient interocclusal space directly interferes with the fundamental mechanics of swallowing, making it a compelling reason for the difficulty experienced by the patient.