Gypsum Plaster

• Dental gypsum material made from calcium sulfate hemihydrate
• Mixed with water → sets into hard mass
• Used for study models, diagnostic casts, flasking, and mounting
• Low strength and hardness compared to dental stone
• Easy to mix and economical
• Good surface detail reproduction
• Not suitable for high-stress work
• Setting reaction is exothermic
• Commonly used in dental laboratories