The snap ring is the main retainer for removable denture restorations. It is directly clamped on the main abutment and is made of metal. Retention, stabilization and support. The snap ring takes a typical cast three-arm snap ring (positive snap ring) as an example, which consists of a snap ring arm, a snap ring body, a support and a connecting body. 1. Snap ring body Snap ring body, also known as snap ring shoulder: it is the hard part connecting the snap ring arm, the support and the small connecting body, and it is surrounded by the non-undercut area of u200bu200bthe abutment, from the adjacent face to the buccal-lingual axial angle, It can prevent the gingival and lateral movement of the denture, play the role of stabilizing and supporting the denture, and support the clasp arm, so the clasp body is required to have high strength, not easily deformed, located in the non-undercut area, and does not affect the occlusion. 2. The small connector is the part where the snap ring is embedded in the base or connected with the large connector, which mainly plays the role of connection, so that the snap ring and other parts of the denture are integrated into a whole. The connector should not enter the abutment or soft tissue undercuts to avoid compromising seating. 3. The support is often cast as a whole with the snap ring. The so-called three-arm snap ring is a general name for the support as an arm.