Purpose: A project of developing novel silicone materials is proceeding by the cooperation of Japanese Academy of Maxillofacial Prosthetics and GC Company,Japan.We have tested basic properties of trial prosthetic silicone materials and revealed that they have comparable properties with the existing silicone material.The aims of this study are to access color stability of the silicone materials,and to compare two kinds of silicone materials in terms of color changes and patients preferences.