A double-ended knife, with kidney-shaped blades, used in periodontal surgery is a(an):

The correct answer is the Kirkland knife, which is specifically designed for periodontal surgery and features double-ended blades that are shaped like a kidney. This unique blade design allows for better access and maneuverability in the periodontal tissues, making it particularly useful for procedures that involve the gingiva and underlying structures.

The Kirkland knife is favored by dental professionals for its effectiveness in incising tissues and performing flaps during surgeries. Its distinct shape enhances the ability to reach various angles in the mouth, contributing to more precise and controlled surgical outcomes.

In contrast, while the Orban knife is also used in periodontal procedures, it has a different blade design that is more pointed and straight, suited for specific types of incisions. The #12 and #15 blades are types of scalpel blades that are generally used for general surgical procedures, not specifically tailored for periodontal work in the same way as the Kirkland knife.