Evaluation of the Yttrium Oxide Effect on Some Mechanical Properties of (Type III) Dental Stone

Abstract

For many years, gypsum compounds have been used in dentistry. They're used to make casts for various dental laboratory operations. Gypsum products have important characteristics such as "quality, abrasion resistance, compressive strength, hardness, linear setting expansion during setting, and detail replication". Additionally, the use of additives such as gum arabic, ferric oxide, calcium oxide, and calcium carbonate has greatly improved the compressive strength of gypsum products. The purpose of this study was to investigate the effects of yttrium oxide (Y₂O₃) addition on the hardness and compressive strength of dental stones. Thirty dental stone specimens of (type III) were prepared and separated into (3) groups: group (A) control group, no additives, group (B) 3% Y₂O₃, and group (C) 5% Y₂O₃. The control and experimental groups' mechanical parameters (surface hardness and compressive strength) were measured, and a Shore D hardness tester was used to indent the specimens. An electronic universal testing apparatus with computer control was used to conduct the compressive strength test. The Tukey-HSD test found no difference in surface hardness between the control and experimental groups, a non-significant difference in compressive strength between the control group and dental stone +3% Y₂O₃, and a significant difference in compressive strength between the control group and dental stone +5% Y₂O₃. Between dental stones with 3% and 5% Y₂O₃, there was a substantial difference in compressive strength. The addition of yttrium oxide at weight ratios of 3% and 5% to dental stone did not affect the surface hardness. The addition of 5% yttrium oxide decreased the compressive strengths.