ADDITION SILICONE

• Hydrophobic
• Polyvinyl siloxane – another name
• Catalyst – platinum
• By-product – H2 gas – smaller molecule
• Least dimensional change
• Most accurate impression material preferred for onlay cavity
• OSMF patients (less mouth opening)
• Never pour immediately, wait for 30 mins for the release of H2 gas – if not pin-point depression on cast
• Expensive – disadvantage
• Only vinyl gloves – no latex