Classification according to the number of snap ring arms:

The clasp arms can be divided into single-arm clasp, double-arm clasp and three-arm clasp. ①Single-arm snap ring: There is only one snap ring arm, which is mostly made of steel wire. When using a single-arm snap ring, the tongue (palate) side must be opposed with a base to prevent the abutment from being displaced by force. This snap ring has no supporting effect. Another single-arm snap ring commonly used in clinical practice is a gap snap, also known as an interdental snap ring. (occlusal) abduction gap preparation gap card groove), curved to the undercut area of u200bu200bthe buccal (labial) surface of the abutment, and confronted with a high base on the lingual side. In addition to the retention function of the gap card, it also has a supporting role through the (occlusal) abduction gap. ②Double-arm clasp: there are two clasp arms, buccal and lingual, the buccal side is the retention arm, and the lingual side is the antagonistic arm, which is mostly used for the periodontal tissue with poor health and mildly loose abutments, which cannot be placed (dental teeth). occlusal) rest, or the occlusion is too tight to prepare the abutment in the concave position of the raised rest. The double arm snap ring is only for retention. ③Three-arm clasp: It is composed of two clasp arms of cheek and tongue and (occlusal) support, which has good support, retention and stability. It is used for posterior teeth with stable teeth, healthy periodontal tissue, and favorable shape of the crown to retain the retaining ring. It is the most commonly used retaining ring in clinical practice. Casting and bending are available, and the lingual arm can also be replaced by a base.