Which of the following factors does NOT impact the performance of an RPD?

The relative cost of dental treatment does not directly influence the performance of a removable partial denture (RPD) in terms of its functional capabilities or effectiveness. Performance is primarily dictated by how well the RPD fits, how it retains in the mouth, the materials used in its construction, and the patient's oral hygiene habits which can affect the longevity and overall condition of the prosthesis.

In situations where cost may restrict certain choices, it is important to note that while a more expensive RPD might incorporate superior materials or technology, the cost itself does not inherently change how an RPD performs once it has been fabricated. Therefore, the efficiency, comfort, and stability of an RPD are more intimately related to the execution of the dental principles and practices involved in its design and fitting, rather than to the financial implications of the treatment itself.