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Prosthodontics & Occlusion · single question

In an RPD, what are the components of the RPA clasp?

  1. R = Reciprocal arm; P = Proximal plate; A = Auxiliary rest
  2. R = Rest (always mesial); P = Proximal plate (distal); A = Aker's retentive arm (wrought wire)
  3. R = Rigid connector; P = Pressure plate; A = Abutment rest
  4. R = Retentive arm; P = Palatal strap; A = Anterior rest
  5. R = Ring clasp; P = Proximal extension; A = Articulated joint
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Correct answer: B. R = Rest (always mesial); P = Proximal plate (distal); A = Aker's retentive arm (wrought wire)

✓ B) R = Rest (mesial), P = Proximal plate (distal), A = Aker's retentive arm (wrought wire).
RPA Clasp components: 'R' = Occlusal REST, always placed on the MESIAL of the abutment tooth (to allow food and tissue movement). 'P' = Proximal PLATE, located distally. 'A' = Aker's retentive arm, always made of WROUGHT wire (not cast) — provides flexibility and engages the distobuccal undercut. The RPA is used for distal extension RPDs. A non-retentive RECIPROCAL arm balances the retentive arm.

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