Depth of cure evaluation of four different light-activated composites using different curing modes

Abstract

ABSTRACT
Background: As light passes through the bulk of the composite material, the light intensity is greatly reduced due to
light absorption and scattering by resin composites, thus, decreasing the effectiveness of cure through the depth of
the composite layer. This study investigated the influence of different new curing modes (conventional and
experimental) and composite formulations on depth of cure using the ISO scraping test.
Materials and methods: This study investigated the depth of cure (ISO scraping method) of four conventional
composites after exposure to different curing modes. A two-piece aluminum mold with a diameter of 4mm and a
height of 8mm was used as a mold for the composite specimens.VIP light curing unit was used to deliver all the
curing modes for photo-curing of all the composite specimens in this study. Parameters included six curing modes:
Control (C), Pulse Delay I (PDI), Pulse Delay II (PDII), Soft-start (SS), Pulse Cure I (PCI), and Pulse Cure II (PCII) plus three
experimental curing modes of higher energy density: Prolonged low-intensity pulse cure mode (PLPC), Prolonged
moderate-intensity pulse cure mode (PMPC) and Rapid high-intensity continues cure mode (RHCC) for each of the
four different light-activated composite materials (Tetric Ceram, Heliomolar, Herculite XRV and Degufill Mineral). The
height of the cylinder of cured material was measured with a micrometer to an accuracy of 0.01 mm. This value was
divided by two (in compliance with ISO CD4049: 2000), and recorded as the depth of cure in mm for that specific
specimen.
Results: Statistical analysis of the data by using the one-way analysis of variance revealed that, there is statistically
very highly significant difference for all the depth of cures between the curing modes and composite types.
Conclusion: This study indicated that, although, both curing mode and composite type significantly affect depth of
cure but the effect of composite composition on the depth of cure is more predominant than that of curing mode.
Key words: Resin composite, light curing modes, composite depth of cure. J Bagh Coll Dentistry 2009; 21(1):5-8)