RPD Review Questions
As fewer teeth remain, the edentulous areas become larger. In general, a stock tray will perform adequately in areas where teeth remain but relatively poorer in edentulous areas. This is one of the major reasons an altered cast impression is done. However, when the number of teeth is very few and the edentulous areas are very large, it is sometimes easier to make a custom tray and border mold before the impression is made. In this way, the altered cast procedure can usually be omitted.