Impression tray for preliminary edentulous impression should be selected such that the edentulous stock tray is:: (A) 5 mm larger than outside surface of ridge, (B) 7 mm larger than outside surface of ridge, (C) 3 mm larger than outside surface of ridge, (D) None of the above
Answer is A. An edentulous tray should be selected, such that it provides for 5mm of bulk of material over entire basal seat area.