Final answer:
To create the 'drop the box' of an inlay Class II preparation, a tungsten carbide or diamond bur is typically used for their precision and ability to create sharp line angles and smooth walls necessary for inlay restorations.
Step-by-step explanation:
The student is asking about a procedure related to dental restorations, specifically an inlay Class II preparation. In these dental procedures, a bur is a drill piece used by dentists to cut, grind, and remove tooth tissue. To create the "drop the box" of an inlay Class II preparation, which is the portion of the preparation on the side of the tooth that is perpendicular or nearly perpendicular to the occlusal surface, a tungsten carbide bur or a diamond bur can be used. These types of burs allow for precision and are effective at creating the sharp line angles and smooth walls required for an ideal inlay preparation.