Investment material used for high fusing base metal partial dentures: (A) Gypsum bonded., (B) Phosphate bonded., (C) Silica bonded., (D) All of the above.
Answer is C. Silica bonded
• Silica is the binder which may be derived from ethyl silicate or silica gel
• Used for high fusing base metal partial denture alloys
• In addition to setting shrinkage "green shrinkage" occurs due to loss of alcohol and water from the gel.
• The investment can be heated upto 1200°C