V2I6P30

‘Pump Handle Effect’ in RPD Design- A Review

Dr. B. Lakshmana Rao^1*

Abstract

A major biomechanical phenomenon in the construction of removable partial dentures (RPDs), the pump handle effect primarily affects Kennedy Class I and II distal-extension prostheses.  The denture base rotates around a fulcrum, usually made up of distal rests, as a result of the remnant ridge tissues’ compressibility under occlusal force.  The abutment teeth are subjected to torquing stress during this rotation, which increases the risk of cavities, diminished retention, ridge resorption, clasp deformation, mobility, and patient discomfort.  Because of the robust abutment support, the effect is negligible in tooth-supported Class III and IV RPDs.  In addition to stress-breaking clasps, implant support, and modified cast procedures, mitigation depends on the positioning of mesial rests in RPI and RPA systems to move the fulcrum and permit clasp disengagement.  As such very scanty literature is available on the effects of ‘Pump Handle Effect on RPD designs. This review paper elaborately discusses the role of pump handle effect and how to modify the RPD design.

Keywords:

RPD Design; Biomechanical Principles, Pump Handle Effect