Properties of gypsum with the addition of gum arabic and calcium hydroxide

• Published in: The Journal of prosthetic dentistry Vol. 76; no. 5; pp. 530 - 534
• Main Authors: Alsadi, Sally, Combe, Edward C, Cheng, Yuan-Sheng
• Format: Journal Article
• Language: English
• Published: United States Mosby, Inc 01-11-1996
• Subjects: Analysis of Variance; Calcium Hydroxide - chemistry; Calcium Sulfate - chemistry; Compressive Strength; Dental Models; Dentistry; Gum Arabic - chemistry; Hardness; Materials Testing; Statistics, Nonparametric; Tensile Strength
• ISSN: 0022-3913; 1097-6841
• DOI: 10.1016/S0022-3913(96)90013-X

The purpose of this work was to study the effects of adding a mixture of gum arabic and calcium hydroxide to a type III stone and an improved die stone. The effect on the water/powder ratio, compressive and tensile strength, hardness, and setting expansion was determined. Data for mechanical properties were subjected to two-way analysis of variance, followed by the Bonferroni-Dunn procedure to determine any significance (1%) between pairs of means. For the type III material the additives had little effect on setting expansion, but the additives significantly improved surface hardness. The additives did not improve compressive or tensile strength for the type III materials. In contrast, the improved die stone's hardness was not enhanced by the additives, and in some instances a reduction in strength was observed. It was concluded that dental cast materials with superior surface properties can be produced by a simple change of formulation.