RPD Reciprocation — NDEB AFK MCQ

Correct answer: A — A rigid reciprocal arm on the opposite side of the tooth from the retentive clasp prevents tooth movement during clasp engagement and disengagement

Reciprocation in RPD design requires that when the retentive clasp arm engages an undercut on one side of the tooth (applying force to flex past the survey line), a rigid reciprocal element (reciprocal arm, minor connector, or guiding plate) on the opposite side simultaneously contacts the tooth above the survey line, preventing the tooth from being pushed away. Without reciprocation, the retentive clasp would displace the tooth laterally rather than flex past the undercut. The reciprocal element must contact the tooth before the retentive tip crosses the survey line.

Reference: Carr – McCracken's Removable Partial Prosthodontics, 13th ed., 2015