What instrument is typically used to adjust a suprabulge clasp to ensure the retentive tip touches the tooth surface?

The instrument most commonly used to adjust a suprabulge clasp and ensure that the retentive tip makes proper contact with the tooth surface is the bird-beak pliers. These pliers are designed with two curved jaws that can grasp and manipulate the wire used in clasps effectively. The shape of the bird-beak pliers allows the operator to create precise bends and adjustments in the clasp, which is crucial for achieving the correct fit and retention on the tooth.

Using bird-beak pliers enables the clinician to make fine adjustments, ensuring that the retentive arm of the clasp captures the tooth adequately, providing optimal stability and support for the removable partial denture. This is essential for the denture's functionality and patient comfort, as it prevents any movement or dislodgment during normal activities such as eating or speaking.

The other instruments listed have different primary uses: three-prong pliers are primarily used for manipulating loops in wire for seating, composite guns are used for applying composite materials, and calipers are generally used for measuring dimensions rather than making adjustments to clasps. Thus, the bird-beak pliers are specifically suited for the adjustment of clasps in the context of removable partial dentures.