Which impression material is typically used for preliminary impressions?

The use of alginate as an impression material for preliminary impressions is a standard practice in dentistry. Alginate is favored because it is easy to mix and handle, providing a rapid setting time that is convenient for capturing an initial mold of the teeth and soft tissues. This flexibility allows dental professionals to create accurate impressions for diagnostic purposes, study models, or fabricating custom trays.

Additionally, alginate is an irreversible hydrocolloid, meaning that once it sets, it cannot return to its liquid state, which is ideal for obtaining stable preliminary impressions. Its ability to capture fine detail and its compatibility with various dental procedures make it an ideal choice for capturing the anatomy of the oral cavity in a preliminary context.

While other materials like polyvinyl siloxane and silicone are excellent for definitive impressions due to their precision and detail, they are typically not used for the initial impressions due to higher costs and more complex handling requirements. Wax may be used in some applications but is not suitable for preliminary impressions due to its lack of stability and detail retention when compared to alginate.