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Prosthodontics

RPD Design in 6 Steps (OSCE & Viva Friendly Guide)

A repeatable RPD design sequence that helps you think like an examiner.

Quick Answers

What is the first step in RPD design?

Determine the support: teeth, mucosa, or both. It decides the entire framework.

Which component provides retention?

Retentive clasps engaging undercuts on abutment teeth.

Which component provides stability?

Proximal plates, minor connectors, guide planes, and rigid components.

What is the major connector for the maxilla?

Commonly palatal strap, AP palatal strap, or complete palatal plate.

1. Assess the case and define support

Support = what resists vertical forces. It comes from:

  • Teeth (occlusal rests)
  • Mucosa (distal extension cases)
  • Combination of both

This FIRST decision directs the rest of your RPD design.

2. Choose the major connector

The major connector unites the entire framework. Examiners expect you to pick it based on arch & mouth conditions.

Common Major Connectors

  • Maxilla: palatal strap, AP palatal strap, complete palate
  • Mandible: lingual bar, lingual plate, sublingual bar

Selection depends on tori, soft tissue depth, and number of missing teeth.

3. Plan retention (clasp assembly)

Retention comes from clasps that engage tooth undercuts (0.25 mm or 0.5 mm depending on alloy).

Clasp System Components

  • Retentive arm (engages the undercut)
  • Reciprocal arm (opposes horizontal forces)
  • Rest (provides support)
  • Minor connectors (connect rests to major connector)

Examiners want you to mention that retention must be balanced bilaterally.

4. Plan stability & guidance

Stability is resistance to horizontal displacement.

  • Guide planes
  • Proximal plates
  • Rigid minor connectors
  • Base contacts

Guide planes should be smooth, 2–3 mm height, placed on prepared surfaces.

5. Tooth replacement & saddle design

Design the bases and saddle areas based on Kennedy classification.

Saddle Design Notes

  • Kennedy I & II → require careful stress distribution
  • Acrylic vs metal base depends on long-term plan
  • Avoid over-extending distal extension saddles

6. Connect everything with a logical design sequence

RPD design is not random. Examiners score your sequence:

  • Support
  • Major connector
  • Retention
  • Stability
  • Saddles
  • Finishing touches (indirect retention, occlusal scheme)

7. Common OSCE / viva mistakes

  • Choosing major connector without considering tori
  • Ignoring indirect retention for Kennedy I / II
  • Unbalanced clasp distribution
  • No guide planes mentioned

8. How DentAIstudy helps

DentAIstudy instantly generates:

  • RPD design templates
  • OSCE scripts for design justification
  • Prostho flashcards
  • One-page RPD summaries

Try Study Builder →

References

  • McGivney GP, Carr AB. McCracken’s Removable Partial Prosthodontics. (Reference-aligned summary)
  • Frank RP. “RPD Design Principles.” J Prosthet Dent.
  • Jacobson TE, Krol AJ. “RPD Design Philosophies.” J Prosthet Dent.
  • Fenlon MR. “Teaching Removable Prosthodontics: Best Practices.” BDJ.
  • Clark RKF. “Guide Planes & Proximal Plates Review.” Prosthodontic Research.