The altered cast impression technique of fabricating removable partial dentures, originally described more than 60 years ago, improves the residual-ridge-to-dentition relationship of the prosthesis. This potentially increases patient satisfaction while preserving the remaining supporting structures. This article reviews research that evaluated abutment tooth movement as a result of the relationship of the denture base to the residual ridge, revealing that improved fit reduced tooth movement. Load distribution studies have shown that a well-fitting denture base distributes stresses favorably to the supporting bone and abutment teeth. Other studies showing that increased residual ridge coverage coupled with a well-fitting denture base reduces stress per unit area, potentially preserving the remaining supporting structures. The article describes a patient who had a unilateral distal extension removable partial denture that was fabricated after the failure of a 20-year-old partial denture due to extensive dental decay. The prosthesis was fabricated over the course of four appointments, and the prosthesis was delivered on the fifth appointment. The patient, who wears the prosthesis daily, expressed comfort and ease of use at a one-year recall examination. Distal extension edentulism can affect a patient's ability to function as a dentate person. A well-made removable partial denture that has appropriate extensions, borders and ridge-to-dentition relationship will benefit the partially edentulous patient by providing increased comfort and improved dental function.