Reinforced dental plaster with low setting expansion and enhanced microhardness

Abstract

Background 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. Improved stone could be used as final casts and dies for building of final indirect dental restorations. 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. 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. Methods The control group was prepared by mixing dental plaster 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 improved stone group was prepared by mixing the improved stone with water. Chemical composition of the three group powders was determined using x-ray florescence spectrometer (XRF). The surface microhardness, compressive strength, and setting expansion were measured. Results 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. Moreover, reinforced dental plaster was shown lower mean setting expansion values compared with conventional dental plaster and improved stones (P value ≤ 0.05). Conclusion 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.

Silver Nanoparticles in Dental Applications: A Descriptive Review

“…The utilitarian approach to ethics cannot keep up with nanotechnology’s rapid growth and unpredictable future. Thus, anticipatory ethics and governance are necessary [ 20 ]. This idea aims to use ethical analysis models early in technology development to identify and address moral and social issues.…”

Evaluation of the Physical-Mechanical Properties of Type IV Gypsum

“…2 All these types of plaster have basically the same chemical composition which is Calcium Sulfate Hemihydrate, differing only in the size and shape of the particles according to the manufacturing process. [3][4][5][6] Some gypsum properties are essential for satisfactory final work because they can directly interfere with their performance. 2,7 The ideal qualities for the plaster to be used as dental models include high surface hardness, that is necessary for the material to resist abrasions and scratches, good reproducibility and low roughness to accurately reproduce the structures copied in the molding, and high compressive strength to avoid damage during the manipulation of the model.…”

“…Evaluation of the Physical-Mechanical Properties of Type IV Gypsum the material setting process, so that they do not affect the fit and the precision of the dental prosthesis. 2,3,7,8 Since dental plasters as well as molding materials are directly related to the accuracy of many procedures, some researches has been carried out to evaluate the physical and mechanical properties of these materials, including microhardness and surface roughness. [9][10][11] De Cesero et al 12 tested the surface roughness of three comercial type IV gypsum varying the storage time of the specimens in order to evaluate the surface quality of the plasters.…”

“…Type IV gypsum is widely used in dentistry mainly in the manufacture of fixed protheses, because it has mechanical properties, such as minimal setting expansion and compressive strength, which stand out when compared to other types of plaster. 2,3,7 Considering the clinical importance of dental plaster properties, the aim of this study was to verify if different trademarks of gypsum type IV present different roughness and surface hardness values. The null hypotesis of this study is that different commercial brands of type IV gypsum will not show any difference in the values of surface roughness and surface hardness.…”

Pengaruh Desinfeksi Model Gipsum Tipe III Menggunakan Sodium Hypochlorite dan Microwave Terhadap Kekuatan Kompresi dan Kekerasan Permukaan

“…Kekuatan kompresi model gipsum tipe III diuji menggunakan Universal Testing Machine (Servopulser,Japan) dari Laboratorium Impact and Fracture Research Centre Universitas Sumatera Utara Faklutas Teknik Program Studi Departemen Teknik Mesin. Setiap sampel diuji dan datanya ditabulasi.Kelompok untuk mengevaluasi kekerasan permukaan model gipsum tipe III disiapkan dengan 30 sampel model gipsum tipe III dengan menggunakan model induk yang dibuat dari bahan PVC dengan ukuran diameter 40 mm x tinggi 10 mm dengan ketentuan ADA/ANSI no.25(Hamdy et al, 2020). Bubuk gipsum tipe III dengan air sesuai pabrikan (100gm/30ml) diaduk menggunakan vacuum mixer selama 20-30 detik dan kemudian adonan gipsum dituangkan ke dalam model induk.…”