National Dental Examining Board of Canada (NDEB) Practice Exam

The use of a reservoir on the sprue of a wax pattern decreases?

1. Melting time

2. Casting porosity during solidification

3. Wax pattern strength

4. Cooling time

The correct answer is: Casting porosity during solidification

Choosing A is not the correct answer because the use of a reservoir on the sprue of a wax pattern does not affect the melting time. The reservoir is used during the casting process, not the melting process. Choosing C is not the correct answer because the use of a reservoir on the sprue of a wax pattern does not impact its strength. The strength of a wax pattern is primarily determined by the quality of the wax and the design of the mold. Choosing D is not the correct answer because the use of a reservoir on the sprue of a wax pattern does not impact the cooling time. The reservoir is used to improve the quality of the casting, not the speed of the cooling process. The correct answer is B because using a reservoir on the sprue of a wax pattern helps to reduce the formation of gas bubbles during the solidification process, which can lead to porosity in the final