Dental OSCE (Objective Structured Clinical Examination) Practice Exam

Which impression material is known for its longest dimensional stability?

1. Alginate

2. PVS

3. Polyether

4. Silicone

The correct answer is: PVS

The impression material recognized for its longest dimensional stability is polyvinyl siloxane (PVS). This choice stands out due to its exceptional properties that include not only dimensional stability but also accuracy in capturing fine detail. PVS materials are characterized by their ability to maintain their shape and characteristics over time, even after the setting process. This property is crucial in dentistry, particularly when constructing restorations or prosthetics, as any distortion in the impression can lead to inaccuracies in the final product. PVS can withstand environmental factors like temperature and humidity better than other materials, which may alter with time. In contrast, other impression materials like alginate typically have less dimensional stability, making them more suitable for short-term use and not ideal for long-term storage. Polyether, while also stable, may not match the longevity offered by PVS. Silicone, which includes various types, generally provides good stability but may not consistently outperform PVS. These characteristics collectively underscore why PVS is the preferred choice for achieving high precision in dental impressions over extended periods.