For a Kennedy Class I maxillary RPD with an anterior-posterior palatal strap, which of the biomechanical requirements is generally of GREATEST concern?

Correct answer: A. Retention

• A. CORRECT — Retention (resistance to vertical dislodging forces) is the most challenging biomechanical requirement in distal-extension RPDs because the free-end bases lack a distal abutment. Clasp design and indirect retainers are used to enhance retention.
• B. Esthetics is a consideration in anterior areas but is not the primary biomechanical challenge for a Class I RPD with this major connector.
• C. Stability (resistance to horizontal forces) is important but generally achievable through cross-arch bracing.
• D. Support is provided through rests and denture bases on residual ridges — usually adequate with a properly designed A-P strap.