What is the roughest surface on cut tooth structure?

The roughest surface on cut tooth structure is typically produced by cross-cut fissure burs at ultra-speed. These types of burs are designed with a specific cross-cut pattern that allows them to efficiently remove enamel and dentin while creating a rougher surface. The high-speed rotation enhances the cutting action, which can lead to a more abrasive interaction with the tooth structure, resulting in a rougher finish.

In contrast, diamond burs, while also effective at cutting, tend to leave a smoother surface due to their design and the way diamond particles are bonded to the bur. Fine-grit diamond abrasives are specifically created to produce a finer surface finish, making them less abrasive compared to cross-cut fissure burs. Coarse ceramic burs can remove material effectively, but their surface finish usually ends up being smoother than that produced by ultra-speed cross-cut fractures. Therefore, the characteristic of cross-cut fissure burs at ultra-speed is what contributes to the roughest surface of the options presented.