The Effect of Different Additives on the Hydration and Gelation Properties of Composite Dental Gypsum

Abstract

Dental mold gypsum materials require fine powder, appropriate liquidity, fast curing, and easy-to-perform clinical operations. They require low linear expansion coefficient and high strength, reflecting the master model and facilitating demolding. In this article, the suitable accelerators and reinforcing agents were selected as additives to modify dental gypsum. The main experimental methods used were to compare the trends of linear expansion coefficients of several commercially available dental gypsum products over 72 h and to observe the cross-sectional microstructure of cured bodies before and after dental gypsum modification using scanning electron microscopy. By adjusting the application of additives, the linear expansion coefficient of dental gypsum decreased from 0.26% to 0.06%, while the flexural strength increased from 6.7 MPa to 7.4 MPa at 2 h. Formulated samples showed good stability and gelation properties with linear expansion completed within 12 h. It is indicated that the performance of dental gypsum materials can be improved by adding additives and nanomaterials, which provided a good reference for clinical preparation of high-precision dental prosthesis.

"Influence of Water Type and Water/Powder Ratio on the Strength and Hardness of Type III and IV Gypsum"

“…Type III and IV gypsum are commonly used to fabricate casts for prosthodontics procedures, as they have acceptable mechanical properties such as high resistance, minimal setting expansion, and high surface hardness resistance [1,3,6,7]. In addition, high accuracy is also essential to accurately reproduce details and for dimensional stability [8][9][10][11][12]. The water/ powder ratio is a critical factor determining the physical and chemical properties of a cast, and any modification of this ratio may alter these properties.…”

Retardation Effects of Filter Mud in Molasses on Composite Silicate Cement

“…Currently, the commonly used retarders include small molecule sugar, inorganic boric acid (inorganic borate), organic lignosulfonate and its derivatives, hydroxycarboxylic acid (hydroxy carboxylate), etc. [ 4 , 5 , 6 ]. Inorganic electrolytes can discharge charged ions by ionisation in an aqueous solution and form a double electrode layer on the surface of the cement particle to prevent the cement particle from bonding with each other, which affects the precipitation nucleation process of Ca(OH) 2 and C-S-H and the formation of C-A-S-H [ 1 ], thereby postponing cement setting and hardening.…”