COMPARISON OF LOAD-TRANSFER BY MAXILLARY DISTAL EXTENSION REMOVABLE PARTIAL DENTURES WITH A SPRING-LOADED PLUNGER ATTACHMENT AND I-BAR RETAINER

This study photoelastically compared the stress distribution characteristics of two maxillary bilateral distal-extension removable partial denture designs, one using I-bar retention and the other using a semiprecision spring-loaded plunger attachment. Each prosthesis was subjected to vertical and horizontal extension-base loads. Comparisons were made from photographic recordings of isochromatic fringe distributions. The two retention designs produced comparable stresses with splinting of abutments for the plunger attachment. The attachment-retained prosthesis proved less stable with some loadings. Stress patterns followed three trajectories in the maxilla. A basis for stress distribution comparisons to other maxillary removable partial denture attachments is established.