@Article{RamosCaLaMaBoCeMe:2016:MiChSC,
author = "Ramos, Nath{\'a}lia de Carvalho and Campos, Tiago Moreira Bastos
and La Paz, Igor Siqueira de and Machado, Jo{\~a}o Paulo Barros
and Bottino, Marco Antonio and Cesar, Paulo Francisco and Melo,
Renata Marques de",
affiliation = "{Universidade Estadual Paulista (UNESP)} and {Instituto
Tecnol{\'o}gico de Aeron{\'a}utica (ITA)} and {Universidade
Estadual Paulista (UNESP)} and {Instituto Nacional de Pesquisas
Espaciais (INPE)} and {Universidade Estadual Paulista (UNESP)} and
{Universidade de S{\~a}o Paulo (USP)} and {Universidade Estadual
Paulista (UNESP)}",
title = "Microstructure characterization and SCG of newly engineered dental
ceramics",
journal = "Dental Materials",
year = "2016",
volume = "32",
number = "7",
pages = "870--878",
month = "July",
keywords = "Ceramics, Dental porcelain, Glass ceramics, Subcritical crack
growth, Stress corrosion, Computer-aided design, Flexural
strength, Young's modulus, Spectroscopy.",
abstract = "Objectives. The aim of this study was to characterize the
microstructure of four dental CAD-CAM ceramics and evaluate their
susceptibility to stress corrosion. Methods. SEM and EDS were
performed for microstructural characterization. For evaluation of
the pattern of crystallization of the ceramics and the molecular
composition, XRD and FTIR, respectively, were used. Elastic
modulus, Poisson's ratio, density and fracture toughness were also
measured. The specimens were subjected to biaxial flexure under
five stress rates (0.006, 0.06, 0.6, 6 and 60 MPa/s) to determine
the subcritical crack growth parameters (n and D). Twenty-five
specimens were further tested in mineral oil for determination of
Weibull parameters. Two hundred forty ceramic discs (12 mm
diameter and 1.2 mm thick) were made from four ceramics:
feldspathic ceramic FEL (Vita Mark II, Vita Zahnfabrik),
ceramic-infiltrated polymer PIC (Vita Enamic, Vita Zahnfabrik),
lithium disilicate LD (IPS e.max CAD, Ivoclar Vivadent) and
zirconia-reinforced lithium silicate LS (Vita Suprinity, Vita
Zahnfabrik). Results. PIC discs presented organic and inorganic
phases (n = 29.1 +/- 7.7) and Weibull modulus (m) of 8.96. The FEL
discs showed n = 36.6 +/- 6.8 and m = 8.02. The LD discs showed a
structure with needle-like disilicate grains in a glassy matrix
and had the lowest value of n (8.4 +/- 0.8) and m = 6.19. The ZLS
discs showed similar rod-like grains, n =11.2 +/- 1.4 and m =
9.98. Significance. The FEL and PIC discs showed the lowest
susceptibility to slow crack growth (SCG), whereas the LD and ZLS
discs presented the highest. PIC presented the lowest elastic
modulus and no crystals in its composition, while ZLS presented
tetragonal zirconia. The overall strength and SCG of the new
materials did not benefit from the additional phase or
microconstituents present in them.",
doi = "10.1016/j.dental.2016.03.018",
url = "http://dx.doi.org/10.1016/j.dental.2016.03.018",
issn = "0109-5641 and 1879-0097",
language = "en",
targetfile = "ramos_microsctructure.pdf",
urlaccessdate = "03 jun. 2024"
}