Effect of two clasping assemblies on arch integrity as modified by base adaptation.

(1) Altering clasp design can affect the way forces act on abutment teeth. (2) An RPI clasp design causes less distal displacement of the primary abutment tooth than circumferential clasp arms with a distal rest under the same conditions. (3) Forces applied on a mandibular distal-extension base will have a greater affect on the abutments on the same side of the arch than on crossarch abutments. (4) The influence of changes in clasp design is minimized when the bases are well adapted to the basal seat and fully extended.