What potential mistake occurs with a single RPD impression?

In the context of removable partial dentures (RPDs), the potential mistake associated with a single impression often involves the distortion of displaceable soft tissue. When capturing an impression, particularly in areas where soft tissue is present, a single impression may not adequately account for the movement or displacement of those tissues. Displaceable soft tissues, such as the buccal and lingual vestibules, can move under pressure or during the impression-taking process. If the impression material does not adequately capture these tissues in their functional position, the resulting RPD may not fit properly, leading to issues with retention, stability, and overall comfort for the patient.

Other options may highlight aspects that could also be problematic, but the specific challenge of capturing the nuances of soft tissue displacement stands out as a critical reason for why a single impression may fall short in accurately informing the design and fit of the denture framework. This underscores the importance of potential dual impressions or techniques that provide a more comprehensive capture of both hard and soft tissues to ensure an effective and well-fitting RPD.