Correlation between microhardness and wear resistance of dental alloys against monolithic zirconia

Abstract

PURPOSE The aim of this study is to compare the hardness according to the conditions of metal alloys. Moreover, the correlation between the cast crown hardness before and after wear testing and the degree of wear for each dental alloy was assessed. MATERIALS AND METHODS Cast crowns of three metal alloys (Co-Cr, gold, and Ni-Cr alloys) opposing smooth-surface monolithic zirconia were used. The Vickers microhardness of the ingot (which did not undergo wear testing) and the cast crown before and after wear testing were measured for each alloy. Two-way ANOVA and Scheffé tests were used to compare the measured hardness values. Moreover, the Pearson correlation coefficient was used to evaluate the relationship between the surface hardness and the wear of the cast crown (α=.05). RESULTS There was no significant difference in the hardness before and after wear testing for the gold alloy ( P >.05); however, the hardness of the worn surface of the cast crown increased compared to that of the cast crown before the wear tests of Ni-Cr and Co-Cr alloys ( P <.05). Furthermore, there was no correlation between the wear and hardness of the cast crown before and after wear testing for all three metal alloys ( P >.05). CONCLUSION There was a significant difference in hardness between dental alloys under the same conditions. No correlation existed between the surface hardness of the cast crown before and after wear testing and the wear of the cast crown.

Behavior of Two Dental Alloys as Ingot and Cast Crown in Artificial Saliva

“…According to reports, a prosthesis's hardness can differ based on the fabrication process it uses, including milling, 3D printing, casting (which can vary depending on the mold used even when using the same casting procedure), and the rate at which the prosthesis cools down after casting. It has been shown that, as grain size increases during the alloy casting process, mechanical strength and surface hardness decrease, even though changes in grain size are independent to changes in yield strength and hardness in the case of gold alloys [32,33]. This study's findings showed that, for both alloys, the hardness of the cast crown was much lower than the ingot's (see Table 6).…”

The 3-year cumulative survival rates of posterior monolithic zirconia crowns and their antagonist teeth, and their influencing factors

“…These complications were associated with the failures of MZCs and survival rates. However, it is noteworthy that a large number of reports have evaluated the wear of opposing antagonist teeth [17][18][19][20][21][22][23]. This concern was raised from the hardness of MZC.…”