California Registered Dental Assistant (RDA) Written Practice Exam

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What gypsum material is most commonly used for fabricating orthodontic diagnostic models?

  1. Stone

  2. Plaster

  3. Die stone

  4. High-strength stone

The correct answer is: Plaster

Plaster is the most commonly used gypsum material for fabricating orthodontic diagnostic models because it is a softer and more workable material compared to the other options. Stone and high-strength stone are harder and less workable, making them more suitable for producing prosthetics. Die stone, while also suitable for prosthodontic purposes, is not as commonly used as plaster in orthodontics. Moreover, plaster is less expensive compared to the other options, making it a more affordable and convenient choice for orthodontic practices.