ABSTRACT
Objective: To evaluate the effects of curing two resin-based composites (RBC) with the same
radiant exposures at 730, 1450, and 2920 mW/cm2. Materials and Methods: Two types of RBC, Filtek Supreme Ultra and Tetric-EvoCeram-Bulk Fill, were light-cured
to deliver the same radiant exposures for 5, 10, or 20 s by means of a modified Valo
light emitted diode light-curing unit with the light tip placed directly over each
specimen. The RBC was expressed into metal rings that were 2.0 and 4.0 mm in thickness,
directly on an attenuated total reflectance Fourier transform infrared plate heated
to 33°C, and the degree of conversion (DC) of the RBC was recorded. The specimens
were then removed and the Knoop microhardness (KHN) was tested at both the bottom
and the top of each specimen. The KHN was tested again after 24 h and 7 days of storage
in the dark at 37°C and 100% humidity. The DC and KHN results were analyzed with Fisher's
protected least significant difference at α = 0.05. Results: The DC values for the specimens cured at the three different irradiance levels were
similar. However, at different depths, there were differences in the DC values. In
general, there were no clear differences among the samples cured in the three different
groups, and the KHN was always greater 24 h and 7 days later (P < 0.05). Conclusions: Despite the curing time, and as long as the samples were cured with the same radiant
exposures, there were no significant effects on the DC and KHN of both RBCs.
Key words:
Bulk Fill - degree of conversion - Knoop microhardness - radiant exposures
