THE EFFECT OF DIFFERENT LED CURING INTENSITIES ON COLOR STABILITY OF NANOFILLED RESIN COMPOSITE

Aim: to evaluate the effect of different LED curing intensities on color stability of nanofilled resin composite.
Materials and methods: nanofilled Resin composite discs specimen (Filtex Z350XT, 3M, ESPE) were prepared and light cured with LED curing unit either standard intensity for
40 sec or high intensity for 20 sec. The specimens’ colors were measured (as a base line) using a portable Reflective spectrophotometer (X-Rite, model RM200QC, Neu-Isenburg, Germany) and measurements were made according to the CIE L*a*b* color space relative to the CIE standard illuminant D65. specimens of each group were immersed for one day in tea solution. After immersion the color changes (ΔE) of the specimens were evaluated. Statistical analysis was then performed. As data was parametric, significance of the difference between groups was evaluated using unpaired t test. The level of significance was set at P < 0.05.
Results: A higher mean value was recorded with high intensity light curing. Unpaired t test revealed that the difference was statistically significant (p=0.0442).
Conclusions: the different light curing intensities might affect the color stability of nanofilled resin composite. The effect of beverages as staining solutions on color stability of resin composite restoration might be immersion-time and resin material dependent. Nanofilled resin composite with optimum polymerization might show more color stability.