Which type of bur is characterized by its ability to create retention for cavity preparation?

The inverted cone bur is designed to create retention for cavity preparations due to its unique shape, which features a tapered end with a wider base. This design allows the bur to create undercuts within the cavity preparation, which locks the filling material in place, enhancing retention. By providing precisely shaped walls that diverge inward, the inverted cone bur helps to ensure that restorative materials remain securely anchored within the cavity, reducing the risk of displacement over time.

In contrast, other types of burs serve different purposes. The round bur is generally used for initial cavity preparation and extends into deeper tooth structure but does not specifically create retention in the same manner. The pear-shaped bur is often used for expanding cavities and improving access but also lacks the same retention features. The straight fissure bur-plain cut is primarily used for cutting and shaping the cavity walls and does not create the necessary undercut features conducive to retention. Thus, the inverted cone bur is uniquely suited for enhancing the retention of restorations within a prepared cavity.