An altered cast procedure to improve tissue support for removable partial denture

Abstract

Free-end saddles are liable to be displaced under occlusal pressure. This is as a result of the displaceability of the mucosa. The altered cast technique is employed to try and prevent this by making an impression of the mucosa under controlled pressure. The metal framework was constructed on a cast produced by a mucostatic impression material. Base plates were then constructed in self-cured acrylics on the framework in the saddle areas, and these are close fitting. Border molding was carried out; impression was made with zinc oxide eugenol impression paste.

In the laboratory, the free-end saddle areas on the master cast are sectioned off. The denture is then positioned on the model and the new saddle areas are poured. The resulting model represents the free-end saddle areas under conditions, which mimic functional load. Denture construction then continues as normal. The distribution of loading of the free-end saddles is improved and denture is more stable.