National Dental Assisting Examining Board (NDAEB) Practice Exam

What is a common characteristic of polyvinyl silicone materials?

1. They are hydrophilic

2. They provide a high degree of accuracy in impressions

3. They have low elasticity

4. They are heat-sensitive

The correct answer is: They provide a high degree of accuracy in impressions

Polyvinyl silicone materials, often referred to as polyvinyl siloxane (PVS), are widely used in dental practice primarily for impression making. A significant characteristic of these materials is their ability to provide a high degree of accuracy in impressions. This accuracy is due to their excellent dimensional stability and low-viscosity counterparts, which can adapt well to the details of the oral structures, capturing fine details of preparation margins and interproximal areas. This precision makes them highly reliable for both diagnostic models and definitive casts required for dental restorations. In contrast to the other options, polyvinyl silicone materials are generally hydrophobic, which means they tend to repel water. They also possess high elasticity, which allows them to recover well after deformation, making them suitable for use in dental applications where flexibility is required. Moreover, these materials are not particularly heat-sensitive, as they maintain their properties and accuracy even when exposed to varying temperatures during handling and setting.