National Dental Examining Board of Canada (NDEB) Practice Exam

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Prepare for the National Dental Examining Board of Canada (NDEB) Exam. Gain confidence with our comprehensive quizzes that include detailed explanations and hints to help you understand key concepts. Excel in your dental career!

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What can be added to decrease the setting time of stone and plaster?

Potassium sulfate
Calcium sulfate dihydrate
Boric acid
Magnesium oxide

The correct answer is: Calcium sulfate dihydrate

Calcium sulfate dihydrate can be added to decrease the setting time of stone and plaster because it acts as a retarder, slowing down the setting process. This gives the user more time to properly mold and shape the material before it hardens. Potassium sulfate, boric acid, and magnesium oxide all act as accelerators, which would speed up the setting process and potentially make it more difficult to work with the material.