![]() ![]() Selection of which type of gypsum products to be used is influenced by their properties and application (Abdelaziz et al. The final dental casts should be fabricated from a substance of a high surface microhardness, strength, and dimensional stability (Manappallil and Manappallil 2016). In order to construct indirect restorations outside the mouth such as inlays, onlays, dental crowns, and bridges, a final dental cast or die must first be fabricated. Therefore, dental plaster is used to fabricate preliminary dental cast (study cast) for a diagnostic purpose and to design the treatment plan. 2017).ĭental plaster is the least strength, stability, and cost than other gypsum products types. Improved stone undergo calcination in a calcium chloride solution to obtain more regular, denser, smaller, and strong particle (Razak et al. Dental plaster manufacturing process depends on rapid and direct heating of the calcium sulfate dihydrate in open air thus, the resultant powder is weak, irregular porous particles. Dental die refers to the positive reproduction of the single prepared tooth. Thus, each type have different mechanical properties (2012 Darvell 2018 Products 2018).ĭental cast is the positive replica of the prepared teeth and other structure of the dental arch. All these gypsum products are chemically have the same composition which is calcium sulfate hemihydrate (CaSo 4.2H 2O) they only differed in particle size and shape according to the manufacturing technique. The American Dental Association (ADA) classify gypsum products into five different types according to their properties and uses which are impression plaster (type I), dental plaster (type II), dental stone (type III), improved stone (type IV), and high expansion improved stone (type V) (ADA 1985). Gypsum products are obtained from natural gypsum minerals. Gypsum products are one of the most broadly utilized dental materials for fabrication of dental casts and dies which are used as for further construction of indirect dental restorations. Within limitation of this study, the results are indicating the opportunity of the innovative reinforced dental plaster to be used alternatively to improved stone (type IV) for fabrication of final dental casts and dies. Moreover, reinforced dental plaster was shown lower mean setting expansion values compared with conventional dental plaster and improved stones ( P value ≤ 0.05). The results revealed that innovative dental plaster reinforced by 10 wt.% aluminum oxide nanoparticle fillers was shown higher mean surface microhardness than that of conventional dental plaster, while higher mean compressive strength values than that of improved stones and conventional dental plaster. The surface microhardness, compressive strength, and setting expansion were measured. Chemical composition of the three group powders was determined using x-ray florescence spectrometer (XRF). The improved stone group was prepared by mixing the improved stone with water. The innovative reinforced dental plaster group was prepared by incorporation of 10 wt.% aluminum oxide nanoparticle fillers to the conventional one prior to water mixing. The control group was prepared by mixing dental plaster with water. This in vitro study was evaluated the effect of incorporation of 10 weight % (wt.%) aluminum oxide nanoparticle fillers on surface microhardness, compressive strength, and setting expansion of the dental plaster compared with the gold standard improved stone. Even though the cost of dental plaster is very low, their inherent lowest surface microhardness, compressive strength, and dimensional stability values confined their utilization as preliminary cast and die materials. ![]() ![]() Improved stone could be used as final casts and dies for building of final indirect dental restorations. Three types of gypsum products were commonly used in dentistry to fabricate dental casts and dies which includes dental plaster, dental stone, and improved stone.
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