The aims of this study are to investigate the effect of light intensity, curing time and combined effect of light intensity and
curing time on the degree of conversion, depth of cure and amount of residual monomer released from composite samples
cured with different light curing units. Single light cured composite restorative material (Herculite XR) exposed to different
types of light curing units (Optilight LD, ULTRA-LITE 200 E plus, Astralis-VIVADENT) at a different exposure times (20, 40
and 60 seconds). The degree of conversion of composite resin samples was investigated by Fourier-transform infrared
spectroscopy. The depth of cure of composite resin samples was investigated by scraping technique using a digital caliper.
While the amount of residual monomer released from cured composite samples was investigated through measuring the
released residual monomer in doubled distilled water with (CECIL 2000) ultraviolet visible spectrometer. Analysis of variance (ANOVA), Post Hoc (T test) and Duncan multiple range test were used for statistical analysis. The result of this study showed that there is a significant difference in the degree of conversion, depth of cure and residual monomer of composite samples with increasing time, increasing intensity and the combined effect of increasing time and intensity except for the degree of conversion in which the combined effect of increasing time and intensity was non-significant. In addition to that, it was shown that the low intensity LED LCU (Optilight LD) exhibit a non-significant result in degree of conversion from those of high intensity (LED and QTH) LCUs at extended period of curing time.
|Journal||Advances in Biomedical Sciences|