What clasp setup is shown?

What clasp setup is shown?

• A. Wrought wire combination clasp
• B. I-bar clasp
• C. T-bar clasp
• D. RPI

Answer: (C)

Recognizing clasp geometry in RPDs and how the shape creates retention is the key idea here. The shown retentive element forms a cross shape: a short horizontal bar sits across the undercut on the tooth, with a vertical stem rising from the tooth to connect to the rest of the framework. This combination gives a distinctive T appearance, which is why it’s a T-bar clasp. The crossbar engages the undercut to provide retention, while the vertical part provides the connection to the rest of the clasping system. This differs from an I-bar, which would be a narrow, single bar along the tooth without a crossbar. It also differs from a wrought wire combination clasp, which would show more irregular, wire-loop elements rather than a clean horizontal crosspiece. And it’s not an RPI configuration, which would show a proximal plate plus a rest and a separate reciprocating element rather than a T-shaped bar.

Recognizing clasp geometry in RPDs and how the shape creates retention is the key idea here. The shown retentive element forms a cross shape: a short horizontal bar sits across the undercut on the tooth, with a vertical stem rising from the tooth to connect to the rest of the framework. This combination gives a distinctive T appearance, which is why it’s a T-bar clasp. The crossbar engages the undercut to provide retention, while the vertical part provides the connection to the rest of the clasping system.

This differs from an I-bar, which would be a narrow, single bar along the tooth without a crossbar. It also differs from a wrought wire combination clasp, which would show more irregular, wire-loop elements rather than a clean horizontal crosspiece. And it’s not an RPI configuration, which would show a proximal plate plus a rest and a separate reciprocating element rather than a T-shaped bar.