Which of the following is a key consideration when sizing a denture?

When sizing a denture, the size and shape of the gums is a crucial factor. This is because dentures need to fit comfortably and securely on the supporting structures of the mouth, which include the gums. The contours of the gums will influence how well the denture adapts, ensuring that it doesn't move during normal functions such as eating or speaking. A proper fit is essential to prevent discomfort, sore spots, and potential complications such as infections.

Other aspects like the color of the denture base may contribute to aesthetics but do not affect the sizing. The material used for cleaning is also irrelevant to sizing; it's more about maintenance after the denture has been fitted. Additionally, while orthodontic treatment influences overall dental alignment, it is not a direct factor in the sizing of dentures themselves. Thus, the dimensions of the gums play a pivotal role in achieving a proper and functional denture fit.