Abstract
The functional behavior of removable partial denture is destined to be transmitted directly to the abutment tooth as a stress via clasp because of most of its retention being dependent upon the clasp retainer. Therefore, the influence of the clasp on the behavior of the abutment tooth is supposed to be more important according to its designs.
Thus, using a bend strain measuring system according to 2 gauge Active-Active method developed previously by the Author and 4 kinds of clasp with a high applicability to cases of distal extention, the Author examined, on experimental models, possible difference horizontal stress on the abutment tooth according clasp designs.
The results are as follows:
1. Both clasp of Supra-bulge type with distal rest and Infra-bulge type with mesial rest exerted respectively to make the abutment tooth incline distolingually.
2. It was showed that the horizontal stress put on the abutment tooth reduced Aker's clasp, Wire combination clasp, Kratochvil I-bar clasp and Krol I-bar clasp in turn, and for the Infra-bulge type clasp was smaller than for Supra-bulge type clasp.
