Abstract
We investigate an adequate method for clinical application of a laboratory-made stud attachment reported formerly. This study was taken to know effects of kinds of metal alloys used for this attachment on its fatigue. 4 kinds of alloys and 14 kinds of assemblies were selected for the male casts (undercut of 0.25mm) and the female wrought wires (diameter of 0.8mm) of 5mm and 7mm length. 10, 000 cycles of engaging and disengaging induced different fatigue in relation to respective characteristics of alloys.
The results:
1. Initial retentive force in Co-Cr female is approximately 1.6 times amounts of the one in Pt-Au and 14K female which is approximately 1.1-1.2 times amounts of the one in Pd-Ag female. The initial retentive force in 7mm length is approximately 1/2 amounts of the one in 5mm length.
2. Abrasion of male, deformation of female and strain hardening of male and female affect on the consequent decrease in retentive force.
3. Strain hardening seems to induce decrease in abrasion of male and decrease in flexibility of female.
4. Decrease in retentive force is caused mainly by abrasion of male.
