National Dental Assisting Examining Board (NDAEB) Practice Exam

What type of gold alloy is used specifically for cast-removable partial dentures?

1. Type 1

2. Extra hard, type 4

3. Type 3

4. Soft, type 2

The correct answer is: Extra hard, type 4

The choice of an extra hard, type 4 gold alloy for cast-removable partial dentures is appropriate due to the specific mechanical properties required for this type of dental application. Type 4 gold alloys are known for their strength and resistance to deformation, making them ideal for frameworks that need to withstand functional stresses during chewing and other oral activities. These alloys are characterized by a higher gold content and include elements that improve their strength and hardness, such as palladium and platinum. Because removable partial dentures often have to provide support for the remaining teeth and withstand biting forces, the extra hard properties of type 4 alloys ensure that the prosthesis is durable and long-lasting, while also maintaining a suitable level of esthetics. The importance of using the correct type of alloy becomes clear when considering the requirements for a removable partial denture framework, which must balance strength, weight, and the ability to adapt to the anatomy of the mouth. Type 4 alloys meet these criteria effectively, making them the preferred choice in this context.