Retentive Properties of Circumferential Clasps Manufactured by Lost-Wax Method and Additive and Subtractive Manufac-turing Techniques

Abstract

Statement of the problem: The number of studies examining the retention properties of circumferential clasps (CC) produced with different manufacturing techniques and metal alloys is still insufficient.

Objective: The aim of this study was to examine the time-dependent changes of the retention abilities of CCs produced using different production techniques and different metal alloys.

Materials & Methods: 5 abutments were produced by selective laser sintering technique with Cr-Co alloy to use during retention tests. 20 wax CCs were formed on the abutments using standard wax pattern, and 10 Cr-Co (Cr-CoL) and 10 titanium (TiL) CCs were manufacturing using conventional lost wax (LW) method. A virtual CC was designed on digitized abutments using dental CAD software, and STL data of the CC was obtained. 10 CCs were fabricated from Cr-Co (Cr-CoA) by additive manufacturing method (AMM). Using the same virtual CC design and subtractive manufacturing method (SMM), 10 CCs from Cr-Co blocks (Cr-CoS) and 10 CCs from titanium blocks (TiS) were produced. The clasps were subjected to a total of 3000 insertion-removal simulation tests (IRST) using a specially prepared experimental setup.

Results: The initial retention forces of the CCs belonging to 5 different groups are listed as follows; TiS (13.1 N), Cr-CoL (10.8 N), TiL(9 N), Cr-CoS (8.5 N), Co-CrA (8.4 N). At the end of 3000 cycles, the retention values of the CCs belonging to 5 different groups are as follows; TiS (17.3 N), Co-CrS (14 N), Co-CrL (12.6 N), Co-CrA (11.8 N), TiL (10.6 N). Significant differences were found between the retentive force values of the CCs in the TiS and Cr-CoA (P=0.02) and TiS and TiL (P=0.01) groups.Conclusion. Vital bleaching agents have the potential to alter the color features of ceramic materials.

Conclusion: CCs manufactured by SMM have a higher retentive force value than clasps manufactured by LW and AMM. The retentive force values ​​of the CCs increase as the number of simulations increases.