What characteristic defines the straight fissure bur-crosscut?

The characteristic that defines the straight fissure bur-crosscut is that it has parallel sides with horizontal cutting edges. This design is crucial for its function in dentistry, as the parallel sides allow for precise removal of hard dental tissue, especially in cavity preparations. The horizontal cutting edges enhance the bur's ability to cut effectively, making it suitable for tasks that require accuracy and efficiency in shaping and preparing tooth structures.

While other options may describe various features or uses of different types of burs, they do not pertain specifically to the defining characteristics of the straight fissure bur-crosscut. Understanding the specific design traits of dental instruments like this one is important for dental professionals, as it influences their choice of tools for specific procedures.