Effectiveness of four different light-activated composites cure with different light energy densities

Abstract EN

Background : This study investigated the influence of light energy density (intensity x time) on the effectiveness of composite cure in view of the curing profiles of light-polymerization units with different light- activated composites to determine the energy density that satisfies adequate polymerization of all light-activated composites types used in this study.

Materials and methods : This study investigated the hardness of the top / bottom surfaces and hardness ratio of two mm thick composite specimens after exposure to different light energy densities.

Parameters included five light intensities (200, 300, 400, 500 and 600 mW / cm2) and seven irradiation times (20, 40, 60, 90, 120, 150 and 180 seconds) for each of the four different light-activated composite materials (Tetric Ceram, Heliomolar, Herculite XRV and Degufill Mineral).

Results : Statistical analysis of the data by using the one-way analysis of variance revealed that, most of the hardness ratios exhibited a very highly significant difference according to intensity, composite type and curing time.

The results indicated that, Heliomolar and Degufill Mineral light-activated composites required approximately (36 J / cm²) energy density for adequate polymerization for a two-mm thick specimen while, Herculite XRV and Tartaric Ceram light-activated composites required approximately (12 J / cm²) energy density for adequate polymerization for a 2-mm thick specimen.

Conclusion : This study indicated that, final curing should not be done with energy density less than (300 mW / cm2 for 120 seconds, 400 mW / cm2 for 90 seconds and 600 mW / cm2 for 60 seconds) for Heliomolar and Degufill Mineral light-activated composites.