# Best investment for casting base metal crowns is:
A. Phosphate bonded investment
B. Gypsum bonded investment
C. Ethyl silicate
D. High grade silicate bonded
The correct answer is: A. Phosphate bonded investment.
Gypsum bonded investments are used for casting gold alloys. These can withstand a temperature of 700 degree C.
Base metal alloys, high melting gold alloys, which are used for metal ceramic restorations, are invested by phosphate bonded investments.
Silica bonded investments are an alternative to the phosphate bonded investments, for high temperature casting. They are used in the casting of base metal alloy partial dentures.
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