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

الملخص EN

Background : the degree of polymerization of resin composites generally decreases from the surface of the restoration inwardly.

Ideally, the degree of polymerization of the composite should be the same throughout its depth and the hardness ratio should be very close or equal to one and can be considered a good indicator for optimal composite polymerization.

This study investigated the influence of different new curing modes on the effectiveness of cure of conventional light- activated composites to examine their efficacy in satisfying composite adequate polymerization (hardness ratio ≥ 0.8).

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 curing modes.

Parameters included six conventional 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 composites being tested (Tetric Ceram, Heliomolar, Herculite XRV and Degufill Mineral).

Results : results revealed that, there was a statistically significant difference for all the hardness ratios with the curing modes except the hardness ratio of Heliomolar composite where, there was an insignificant difference because, the mean hardness ratio of Heliomolar composite with the first six curing modes (control, PDI, PDII, SS, PCI, PCII) was not calculated because of poor polymerization of Heliomolar bottom surfaces with these six curing modes.

Conclusion : this study concluded that, conventional curing modes had failed to cure Heliomolar and Degufill Mineral composites adequately while the experimental curing modes of high energy density (PLPL, PMPC and RHCC) had satisfied effectiveness of composite cure for all the composites being tested.