The Effect of Recasting on Microhardness of Cobalt/Chromium Base Metal Alloys

Abstract

Castings made of base metals include the cobalt/chromium alloy. This alloy is frequently used in dentistry to make crowns, bridges, and partial dentures. This alloy was first promoted as a less expensive option to cast gold that had even better physical and mechanical properties and approximately comparable bioco mpatibility. It was better suited for long-span bridges and cast prostheses. Aim: to assess how recasting affects the cobalt/chromium base metal alloys' microhardness. Material and Methods: 42 disc-shaped specimens of cobalt/chrome alloy measuring 5 mm in diameter and 3 mm in thickness were prepared. The cast specimens were divi ded into three groups based on the weight of the newly and pr eviously cast Co/Cr alloy addition: the first group was 14 specimens of (new cast) alloy; the second group was 14 specimens of (50% new cast+50% old cast) alloy; and the third group was 14 specimens of (old cast) alloy. All the speci mens were subjected to measuring the microhardness prope rty by using a digital microhardness tester. Results: Using a student t-test, it was determined that there was no significant difference in the microhardness between the two gr oups (new cast) and (new cast + old cast), and that there was al so no significant difference between the groups (new cast + ol d cast) and (old cast) (P-value p>0.05), yet that there was a highly significant difference between the two groups (new cast) and (old cast) (P-value P<0.01). Conclusion: The incl usion of different ratios of fresh and recast Co/Cr alloys can affect the microhardness. Also, the recast Co/Cr metal alloy has shown excellent results for microhardness property.