National Dental Assisting Examining Board (NDAEB) Practice Exam

What type of impression materials are known to have a strong odor and can permanently stain clothing?

1. Polyvinyl siloxane

2. Alginate

3. Polysulfide

4. Silicone

The correct answer is: Polysulfide

Polysulfide impression materials are known for their distinctive strong odor, which is a result of their chemical composition, particularly the mercaptan groups present in the formulation. This characteristic can be quite noticeable in the clinical setting, especially when the material is mixed and sets. Additionally, polysulfide has the potential to stain clothing permanently due to the same mercaptan components. If these materials come into contact with fabrics, they can leave lasting marks that are typically very difficult to remove. This staining property is important for dental assistants to be aware of when working in a clinical environment, as precautions should be taken to avoid such mishaps. In contrast, other impression materials, such as polyvinyl siloxane and silicone, are either odorless or have a very mild odor and do not usually carry the same staining risk. Alginate, while it may have some odor, is not known for strong odors and does not pose the same staining issues as polysulfide. Therefore, polysulfide is the material that stands out in both strong odor and potential for permanent staining of clothing.