Which factor is considered intraorally and can affect denture fit due to the relationship of lips and cheeks?

• A. Age
• B. Oral hygiene
• C. Musculature
• D. Tobacco use

Answer: (C)

The main concept is how dynamic muscular forces inside the mouth affect denture fit. The lips and cheeks are shaped by muscles such as the orbicularis oris and buccinator, and their activity directly interacts with the denture borders. When these muscles contract or relax during speaking, smiling, or swallowing, they push or pull on the denture, altering the border seal, retention, and stability. Because this influence comes from intraoral muscle action, it is the factor most responsible for how well a denture fits during function.

Other factors like age, oral hygiene, and tobacco use can affect denture fit in other ways—age can change ridge anatomy over time, hygiene can impact mucosal health, and tobacco can affect tissue condition—but they do not account for the immediate intraoral muscle dynamics that shape how the denture seats against the lips and cheeks.