Direct and Indirect Retainers

The clasp assemblies act as the direct retainers of the removable partial dentures (RPDs) without precision attachments. In this chapter, infra- and supra-bulge clasp assemblies used in RPD design are described with their specific features. Components of the clasp assembly and factors that affect the retention of the clasp assembly are defined. In addition, the RPI clasp assembly that is used for the distal extension RPDs is explained in detail. Indirect retention (rests and minor connectors) and its principles to counteract the dislodgement of the RPD are also expressed.