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Influence of different water types on the physical and mechanical properties of gypsum
Proença, Juliana dos Santos; Suzuki, Marcos Massahiro; da Costa, Silvano Cesar; Hirata, Bruno Shindi; Lopes, Murilo Baena & Contreras, Edwin Fernando Ruiz
Abstract
Aim: To evaluate if gypsum mixed with different water types, with their different compositions
influence the dimensional change, surface roughness and compressive strength of type IV and
V gypsum specimens. Methods: Sixty specimens were fabricated from metal matrices and
divided into six groups (n=10) according to the used type of gypsum and water: G1, G2 and G3
– type IV gypsum and tap, mineral and distilled water, respectively; G4, G5 and G6 – type V
gypsum and tap, mineral and distilled water, respectively. Water/powder ratio followed the
manufacturer’s recommendations (19 mL/100 g) in all groups. The same specimens were used
for all tests. A micrometer dial evaluated the dimensional change. The surface roughness of three
random points was determined with a rugosimeter; a universal testing machine performed the
compressive strength test. The data were subjected to analysis of variance (ANOVA). Results:
There was no statistically significant difference (p>0.05) between the three types of water in the
studied variables. There was statistically significant difference (p<0.05) between the gypsum
mixes for the dimensional change variable. Conclusions: The different water types, with their
different compositions, did not influence the analyzed physical and mechanical properties.
Keywords
calcium sulfate; water; compressive strength; dental prosthesis
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