When creating a proximal box for a Class II inlay, how should the bur be positioned?

The correct choice emphasizes the importance of the bur's orientation in relation to the placement of the inlay. When preparing a proximal box for a Class II inlay, holding the bur parallel to the path of placement is crucial. This alignment helps ensure that the walls of the preparation facilitate the proper seating of the inlay without causing interference or compromising the integrity of the surrounding tooth structure.

Positioning the bur parallel to the path of placement enables optimal adaptation of the inlay margins, promoting a more precise fit and enhancing the bond strength between the inlay and tooth structure. This technique reduces the risk of complications such as failure of the restoration due to inadequate retention or potential overhangs that could affect the patient's oral hygiene.

In contrast, tilting the bur against or away from specific walls may create irregularities in the preparation, which could lead to difficulties in seating the inlay properly. Such deviations might also result in undercuts or compromised margins that cannot be adequately sealed, making it essential to maintain the correct orientation during the preparation process.