Influence of radiant exposure and material shade on the degree of conversion and microhardness of a resin-based composite.

Autor:	Beolchi RS, Scaramucci T, Cunha SR, Palazon MT, Braga RR, Shimokawa CAK
Jazyk:	angličtina
Zdroj:	General dentistry [Gen Dent] 2024 Sep-Oct; Vol. 72 (5), pp. 49-53.
Abstrakt:	This in vitro study evaluated the influence of radiant exposure and material shade on the degree of conversion (DC) and microhardness of a resin-based composite (RBC). Sixty-four RBC specimens in shades A1E (enamel) and A4D (dentin) were light cured at a calibrated exitance of 1000 mW/cm 2 for 5, 10, 15, or 20 seconds, resulting in radiant exposure levels of 5, 10, 15, or 20 J/cm 2 . The DC was determined using Fourier-transform infrared spectroscopy (n = 3 per shade per exposure level). The Knoop hardness number (KHN) was measured on the top and bottom surfaces of each specimen (n = 5 per shade per exposure level). Data were analyzed using 2- and 3-way analyses of variance and post hoc Tukey tests (α = 0.05). The RBC shade did not affect the DC (P = 0.860), and the lowest DC values were achieved with an exposure level of 5 J/cm 2 (P < 0.001). The shade did not affect the KHN on the top surface, but the radiant exposure level did, with the application of 5 J/cm 2 resulting in significantly lower values (P < 0.05). For the bottom surface, shade A1E showed significantly higher KHN values than A4D (P < 0.001). An increase in the radiant exposure led to increased DC and KHN for both shades of RBC until reaching a saturation point of 10 J/cm 2 for A1E and the top surface of A4D. The darker and more opaque shade was not adequately polymerized at a 2-mm depth, even when the highest radiant exposure level was applied. Competing Interests: No conflicts of interest reported.
Databáze:	MEDLINE
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