Which gypsum product is typically used to create a diagnostic model?

The use of plaster for creating a diagnostic model is based on its properties and the specific requirements of such models. Plaster, also known as substantial or type I gypsum, is relatively easy to manipulate, inexpensive, and provides sufficient detail for general examination and analysis. It is softer and more porous than the other gypsum products, allowing for easy trimming and shaping, which is beneficial in creating diagnostic models that do not need to exhibit the same durability or strength as models used for more precise applications, like restorations or prosthodontics.

Additionally, plaster's flow characteristics allow it to capture the detail required from the preliminary impressions, making it suitable for diagnostic purposes where high strength is not the primary concern. This makes it a common choice in the dental field for educational purposes, as students can easily work with it and practice model creation.

In contrast, dental stone and high-strength stone are typically used for more durable models requiring greater detail and strength, often necessary for working casts or other precision applications. Impression plaster is used primarily for creating impressions, not models. Thus, plaster is the most appropriate and traditionally used gypsum product for diagnostic models.