Plaster Cast Dental Models vs 3D Digital Models – Which Are Best?

In the past and still today, dental impressions coming into the dental laboratory are cast in plaster. However with the arrival of the 3D scanner, 3D digital dental models are now an option being offered and requested by dentists.

The dental laboratories of old and most today have a dedicated “plaster room” or area. This is usually the first stop for dental impressions on their journey through the laboratory. These impressions are “poured” using Type 2 or 3 of dental plaster (Dental Gypsum).

The current ISO Standard for Dental Gypsum Products identifies five types of material as follows:

Type 1 Dental plaster, impression
Type 2 Dental plaster, model
Type 3 Dental stone, die, model
Type 4 Dental stone, die, high strength, low expansion
Type 5 Dental stone, die, high strength, high expansion

It takes approximately 5 minutes pouring time, 45-60 minutes setting time and approximately 5 minutes to trim up, taking all the excess off and producing an aesthetically, accurate study model.

A scanned impression takes seconds to produce, and is not always 100% accurate in the fine detail, whereas the plaster model is. However the digital route allows for a wider choice of materials to be used in the design of the final appliance.

In an article by Akyalcin (2011) he writes that Digital models can only offer a valid alternative to plaster study models if they are proven to be as accurate. Further studies have shown that digital models can be used for initial diagnosis and treatment planning even though there can be “statistically significant differences” (Akyalcin,2011) between the plaster and digital models.

Therefore in conclusion, evidence suggests digital models will replace plaster models in the future, however Dentists and Dental Technicians are recommended to use both types until the accuracy of the digital models can be accurately and consistently repeated.



Akyalcin,S. (2011) Are Digital Models Replacing Plaster Casts Dentistry ISSN:2161-1122