Knoop hardness of three glass ionomer cements/Dureza knoop de três cimentos de ionômeros de vidro

Fragnan, L.N., Bonini, G.A.V.C., Politano, G.T., Camargo, L.B., Imparato, J.C.P. and Raggio, D.P. ORCID: https://orcid.org/0000-0002-0048-2068 2011. Knoop hardness of three glass ionomer cements/Dureza knoop de três cimentos de ionômeros de vidro. Pesquisa Brasileira em Odontopediatria e Clinica Integrada 11 (1) , pp. 73-76.

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Abstract

Objective: To evaluate the Knoop microhardness of three national glass ionomer cements (GIC) after 24 hours and 7 days. Methods: The materials were dispensed and mixed according to the manufacturers' instructions and divided in groups (n=10): G1: Vidrion R - SS White (conventional), G2: Vitro Molar - DFL (high viscosity) and G3: Maxxion R - FGM (high viscosity). The specimens were fabricated using PVC molds. After 10 minutes, they were immersed in an oily solution (liquid petroleum jell) at 37oC during 24 hours and the surfaces were polished with 600-grit silicon carbide paper (Buehler) in a polishing machine (Aropol 2V, Arotec). Microhardness test was performed in a digital microhardness tester (Pantec HVS-1000) using a Knoop indenter with 25 g load during 30 seconds. Three indentations were made in each specimen and repeated after 1 week, under the same conditions. Results: Knoop microhardness means (and standard deviations) were: after 24 hours - G1: 47.65 (20.1). G2:52.06 (10.6) and G3: 72.43 (17.4); after 1 week - G1: 74.25 (16.5). G2: 87.55 (12.1) and G3: 132.17 (39.7). Statistical analysis by ANOVA and Tukey's test revealed significant difference (p<0.05) between G3 and groups G1 and G2 as well as between the microhardness readings obtained aft er 24 hours and aft er 1 week. Conclusion: The high-viscosity GIC Maxxion R presented higher mechanical property than the GICs Vidrion R and Vitro Molar. The microhardness of these three national GICs increased with time.

Item Type:	Article
Status:	Published
Schools:	Dentistry
Last Modified:	10 Nov 2022 10:58
URI:	https://orca.cardiff.ac.uk/id/eprint/148819

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