Dental Stone vs. Plaster of Paris

Dental Stone vs. Plaster of Paris

• Dental stone is stronger and more durable than Plaster of Paris.
• Dental stone is easy to use and acquire.
• It is a form of plaster, made from calcium sulfate dehydrate, a natural material mined from the earth.
• Calcium sulfate dehydrate is calcinated (heated) to become calcium sulfate hemihydrate, the hardened version.

Using Dental Stone

• Dental stone is mixed with a pre-determined amount of water to achieve a consistency similar to thin pancake batter or thick cream.
• The mixture can be mixed in a container or a Ziplock bag.
• A metal form, cardboard, or built-up surrounding soil can be used as a mold to prevent the casting material from spreading.
• The mold should be slightly larger than the impression, and approximately 2lbs of dental stone to 8oz of water is used.
• The mixture is mixed for 3 minutes before pouring to ensure an even pour and a stronger cast.

The Pouring Process

• Start pouring the mixture just outside of the impression, directing the flow into the impression.
• Move along the impression while pouring to ensure the mixture fills the entire impression.
• Pour behind the leading edge to push the mixture into the impression.
• Once poured, the casting should be left to harden, and a label can be placed into the casting with identifiers, date, location, and initials.

Casting Footwear

• Casting footwear impressions is recommended whenever there is a 3-D impression.
• Casting captures the positive representation of the shoe, including uneven surfaces and microscopic characteristics.
• Casting provides tangible 3-dimensional evidence and confirms photographic evidence.

Casting Impressions in Snow

• Snow Print Wax, developed in 1982, is an aerosol spray that produces a wax shell when applied to the impression, allowing for casting with dental stone.
• Dry casting with dental stone involves layering the impression with dry dental stone and then preparing a regular mix of dental stone.
• Yellow Sulfur can be used to cast impressions in snow, but it is more time-consuming and requires melting and continuous stirring.
• Sulfur Cement, introduced in 2007, is less flammable than sulfur and requires the same method as sulfur.

Key Points

• The amount of detail varies considerably in different types and conditions of snow.
• Impressions in snow should always be photographed first.
• Highlighting impressions can enable better contrast recovered through photography.
• Casts of snow impressions provide additional detail to supplement photography of snow impressions alone.

Compare and contrast dental stone and plaster of Paris, including their properties, uses, and advantages. Learn about their applications in dentistry.