TY - JOUR
T1 - Tensile strength and microhardness of treated human dentin
AU - Fuentes, Victoria
AU - Ceballos, Laura
AU - Osorio, Raquel
AU - Toledano, Manuel
AU - Carvalho, Ricardo M.
AU - Pashley, David H.
N1 - Funding Information:
This investigation was supported by RED CYTED VIII. J, grant MAT 2001-2843-C02 from CICyT, Spain; CNPq grant # 300481/95-0, Brazil.
Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2004/7
Y1 - 2004/7
N2 - Objectives. To determine the ultimate tensile strength and Knoop hardness of mineralized, EDTA-treated, sodium hypochlorite (NaOCl)-treated, EDTA-treated resin-infiltrated, and NaOCl-treated resin-infiltrated dentin. Methods. Dumbell-shaped specimens with a cross-sectional area of 0.5 mm2 were prepared from the crowns of extracted human third molars. Specimens were randomly assigned to the following experimental groups: (1) mineralized dentin; (2) 0.5 M EDTA-demineralized dentin, pH 7/5 days; (3) 5% NaOCl-deproteinized dentin/2 days; (4) EDTA-treated, Single Bond resin-infiltrated dentin; (5) NaOCl-treated, Single Bond resin-infiltrated dentin. All specimens were tested in tension in a Vitrodyne testing machine at 0.6 mm/min. Knoop microhardness was measured on the fractured edges of specimens in groups 1, 3, 4, and 5. Results were analyzed by ANOVA and SNK tests (p<0.05). Results. Both EDTA and NaOCl treatments caused significant reductions in the tensile strength and microhardness of mineralized dentin (p<0.05), with the largest reductions observed after NaOCl treatment (p<0.05). Resin infiltration of treated dentin resulted in moderate increase of its tensile strength and microhardness, however, the original mineralized values were not recovered (p<0.05). Significance. Whenever dentin surfaces are treated with EDTA or NaOCl prior to a clinical bonding procedure, clinicians must be aware that a weak layer may be present at the interface, which may lead to premature failures of resin/dentin bonds.
AB - Objectives. To determine the ultimate tensile strength and Knoop hardness of mineralized, EDTA-treated, sodium hypochlorite (NaOCl)-treated, EDTA-treated resin-infiltrated, and NaOCl-treated resin-infiltrated dentin. Methods. Dumbell-shaped specimens with a cross-sectional area of 0.5 mm2 were prepared from the crowns of extracted human third molars. Specimens were randomly assigned to the following experimental groups: (1) mineralized dentin; (2) 0.5 M EDTA-demineralized dentin, pH 7/5 days; (3) 5% NaOCl-deproteinized dentin/2 days; (4) EDTA-treated, Single Bond resin-infiltrated dentin; (5) NaOCl-treated, Single Bond resin-infiltrated dentin. All specimens were tested in tension in a Vitrodyne testing machine at 0.6 mm/min. Knoop microhardness was measured on the fractured edges of specimens in groups 1, 3, 4, and 5. Results were analyzed by ANOVA and SNK tests (p<0.05). Results. Both EDTA and NaOCl treatments caused significant reductions in the tensile strength and microhardness of mineralized dentin (p<0.05), with the largest reductions observed after NaOCl treatment (p<0.05). Resin infiltration of treated dentin resulted in moderate increase of its tensile strength and microhardness, however, the original mineralized values were not recovered (p<0.05). Significance. Whenever dentin surfaces are treated with EDTA or NaOCl prior to a clinical bonding procedure, clinicians must be aware that a weak layer may be present at the interface, which may lead to premature failures of resin/dentin bonds.
KW - Dentin
KW - Microhardness
KW - Microtensile
KW - Tensile strength
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U2 - 10.1016/j.dental.2003.05.005
DO - 10.1016/j.dental.2003.05.005
M3 - Article
C2 - 15134939
AN - SCOPUS:2342511427
SN - 0109-5641
VL - 20
SP - 522
EP - 529
JO - Dental Materials
JF - Dental Materials
IS - 6
ER -