Gypsum Properties — NDEB AFK MCQ
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Correct answer: A — Decreases the strength and increases the porosity of the set product
Increasing the water-to-powder (W/P) ratio in gypsum mixing results in excess water that evaporates during or after setting, leaving voids (porosity). This decreases the compressive strength, surface hardness, and abrasion resistance of the set gypsum product. It also increases the setting time and reduces accuracy. The correct W/P ratio is critical: dental stone requires approximately 0.28-0.30 mL/g; die stone approximately 0.22-0.24 mL/g.
Reference: Anusavice – Phillips' Science of Dental Materials, 13th ed., 2022