Abstract
Purpose: The purpose of the present study was to obtain fundamental data for application of the cast-on method by evaluating the effect of mold temperatures on the interface between primary and secondary castings in detail.
Methods: Silver-palladium-gold alloy (Ag-Pd-Au), type-4 gold alloy (Type4), and chromium-cobalt alloy (Cr-Co) were used in the present study. A polished flat, square metal plate, 10.0 mm × 10.0 mm × 1.0 mm, was used as the primary casting. Awax pattern, 2.0 mm in diameter and 2.0 mm thick, was prepared for the secondary casting and invested together with the primary casting. The mold was heated at 600, 700 and 800 °C for Ag-Pd-Au and Type4, and 700, 800 and 900 °C for Cr-Co. After casting, the mold was embedded and sectioned. The cross-section was observed using a scanning electron microscope (SEM) and analyzed using energy dispersiveX-ray spectroscopy (EDS).The gaps between the primary and secondary castings were analyzed for each alloy by analysis of variance and Tukey's honestly significant difference test. The significance levelwas set at 0.05. The heated primary casting without the secondary casting was examined using a thin film X-ray diffractometer (XRD).
Results: Gaps were observed between the primary and secondary castings in all examined conditions. The primary casting surface was covered with oxide layers such as CuO and Cr2O3, and became rough with an increase of the mold temperature.
Conclusions: The results suggested that the cast-on method was influenced by the mold temperature.
