Determination of enamel and coronal dentin microhardness
Keywords:Microhardness. Enamel. Coronal dentin
The Vickers microhardness of enamel and coronal dentin of 30 canines was evaluated. The incisal portion of the crown was discarded by means of a transverse section made 5mm, coronally, from the cemento-enamel junction located on the buccal surface obtaining, thus, the coronal specimen, on which measurements on 3 regions of each dental tissue was carried out. The mean value of microhardness at the E1 region (0.05 to 0.1 mm from the external surface) was of 395.92 VHN and at the E2 region (0.3 to 0.5 mm from the external surface) was of 339.41 VHN, E1 and E2 being, statistically different. The mean microhardness at the E3 region (0.05 to 0.1 mm from the dentinoenamel junction), for the free surfaces, was of 255.02 VHN, and for the proximal surfaces, was of 269.72 VHN. Following statistical analysis (Variance Analysis Test, p < 0.05), we concluded that enamel microhardness decreased from the external surface towards the dentinoenamel junction. The mean microhardness of coronal dentin was obtained in 3 regions: the DC1 region (0.05 to 0.1 mm from the dentinoenamel junction) - with a mean of 38.68 VHN; the DC2 region (0.3 to 0.5 mm from the dentinoenamel junction) - with a mean of 56.42 VHN; and the DC3 region (0.8 to 1.0 mm from the dentinoenamel junction) - with a mean of 36.49 VHN. Microhardness at DC2 was statistically greater than that of DC1, which, in turn was greater than that at DC3.
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