Variations in the Compressive Strength of a Die Stone with Three Different Sulfates at Eight Different Concentrations: An In Vitro Study
Rajesh Vyas, Sunil K Vaddamanu, Vishwanath Gurumurthy, Mohamed S Kuruniyan, Syed A Quadri, Masroor A Kanji
Compressive strength, Die stone, Sulfate
Citation Information :
Vyas R, Vaddamanu SK, Gurumurthy V, Kuruniyan MS, Quadri SA, Kanji MA. Variations in the Compressive Strength of a Die Stone with Three Different Sulfates at Eight Different Concentrations: An In Vitro Study. J Contemp Dent Pract 2019; 20 (11):1297-1306.
Aim: The present study aimed to evaluate the alteration in the compressive strength (CS) of the die stone with three different sulfate salt additives, each at eight various concentrations.
Materials and methods: The specimens were prepared at specific dimensions (length: 2.5 cm and diameter: 2.5 cm) divided into three test groups based on the type of sulfate additives used [potassium sulfate (K2SO4), zinc sulfate (ZnSO4·H2O), and manganese sulfate (MnSO4·H2O)] and one control group, without any additives. Again, each group was divided into eight subgroups based on concentration of sulfates (ranging from 0.2% to 4%). A total of 375 specimens were tested. CS (in MPa) was evaluated after 72 hours of drying time, using an universal testing machine.
Statistical analysis: A one-way analysis of variance (ANOVA) was used for intergroup comparisons. Individual comparisons were done using the post hoc Tukey HSD analysis.
Results: All the three additives at all the concentrations have shown an inferior resistance to compressive forces when compared to the standard specimen. However, the least mean CS was observed at 0.8% of MnSO4 (10.95 MPa) and the highest was at 1% K2SO4 (25.28%). A highly significant difference (p < 0.001) was observed among the concentrations in all the three groups (K2SO4, MnSO4, and ZnSO4 groups) and F values were derived as 69.84, 24.29, and 130.52, respectively. At each concentration, comparisons between the groups have shown a significant difference (p < 0.05) at almost all concentrations.
Conclusion: The CS of die stone is shown to be decreased with an increase in all three types of sulfate additives when compared to the control specimen.
Clinical significance: Die stone is an often used gypsum material in the field of dentistry. Compressive strength of the die stone is crucial in prosthetic dentistry; chemical additives such as sulfate salts may increase the CS such that the die stone can withstand clinical and laboratory handling forces.
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