Dental Materials Journal
Online ISSN : 1881-1361
Print ISSN : 0287-4547
ISSN-L : 0287-4547
Original Papers
Machinable glass-ceramics forming as a restorative dental material
Duangrudee CHAYSUWANKrongkarn SIRINUKUNWATTANAKanchana KANCHANATAWEWATGreg HENESSKimihiro YAMASHITA
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2011 Volume 30 Issue 3 Pages 358-367

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Abstract

MgO, SiO2, Al2O3, MgF2, CaF2, CaCO3, SrCO3, and P2O5 were used to prepare glass-ceramics for restorative dental materials. Thermal properties, phases, microstructures and hardness were characterized by DTA, XRD, SEM and Vickers microhardness. Three-point bending strength and fracture toughness were applied by UTM according to ISO 6872: 1997(E). XRD showed that the glass crystallized at 892°C (second crystallization temperature+20°C) for 3 hrs consisted mainly of calcium-mica and fluorapatite crystalline phases. Average hardness (3.70 GPa) closely matched human enamel (3.20 GPa). The higher fracture toughness (2.04 MPa√m) combined with the hardness to give a lower brittleness index (1.81 μm−1/2) which indicates that they have exceptional machinability. Bending strength results (176.61 MPa) were analyzed by Weibull analysis to determine modulus value (m=17.80). Machinability of the calcium mica-fluorapatite glass-ceramic was demonstrated by fabricating with CAD/CAM.

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© 2011 The Japanese Society for Dental Materials and Devices
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