Comparative Evaluation of the Discoloration of Microhybrid and Nanohybrid Composite Resins by Different Beverages: A Spectrophotometric Analysis.

Background: Composite resins are choice of restorations due to their lifelike characteristics. Recently "microhybrid" and "nano- hybrid" composites have been introduced. Microhybrids and Nanocomposites have a small particle size and possess better qualities as compared to traditional composite resins. The intake of beverages like black tea, coffee green tea has increased in the community. The beverages cause discoloration with time on the composite restorations making it aesthetically unacceptable.

Aim: Aim is to evaluate discoloration of microhybrid and nano- hybrid composite resins by black tea, black coffee, green tea and distilled water at 0, 3, 6, 9, and 12 days.

Methodology: 160 samples were fabricated in molds from two nanohybrid composite and two microhybrid composites. They were light cured and allocated into four groups were stored in an incubator throughout the experiment at 37° C. Initial baseline color was recorded by a spectrophotometer. These samples were immersed in vials containing black tea, black coffee, green tea and distilled water for three, six, nine, 12 days. Color analysis was done at each interval.

Statistical Analysis: Data was tabulated and the readings after immersion and baseline were compared between four composite resins. Data were analyzed using the appropriate test by testing normality. A value <0.05 was considered to be significant.

Results: Significant discoloration was observed in all four composite resins. Discoloration increased from the third day to 12th day. Maximum discoloration was observed on the 12th day.

Conclusion: The order of discoloration in the beverages was: Flash > Tetric n ceram > matrix > tetricceram. The order of discoloration caused by test solutions on composite resin was: Black coffee>black tea>green tea > distilled water.