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Casting materials

المؤلف:  Max M. Houck، Jay A. Siegel

المصدر:  Fundamentals of Forensic Science

الجزء والصفحة:  583

2026-09-06

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Casting materials

Plaster of Paris has long been the most popular casting material for all types of impressions. Its major drawback is its softness even after drying. It is also made up of relatively large particles that may cause the loss of crucial detail. Today, dental plasters and stones are more often used. They are denser and have more uniform, smaller particle size than plaster of Paris. They dry quickly and show more detail. The softness of plaster of Paris necessitates that reinforcing materials such as pieces of wood be used within the cast. This requires that casts be at least two inches thick. In order to make a cast that thick, a form has to be used. With modern dental stones and plasters, the increased density and hardness of the dried casting material means that the cast doesn’t have to be as thick and therefore, often doesn’t require a form. Forms are still some times used if the impression is on a steep slope or is of different depths throughout.