Color evaluation of composite resin using dental colorimeter according to the specimen size

Abstract

The purpose of this study was to evaluate the color of a single shaded composite resin of various specimen sizes, using a dental colorimeter. Four separate transparent acrylic plates were prepared, 40 mm × 20 mm in size and 2 mm in thickness, and two holes of 6.5 mm, 8.5 mm, 10.5 mm, or 12.5 mm in diameter were drilled on each different plate. The holes were filled with A3 shade flowable composite resin (DenFil Flow), and lightly cured (n = 10). After separation of the specimens from the plates, CIE L*a*b* values of the resin specimens were measured with a dental colorimeter (ShadeEye NCC). Data were analyzed with one-way ANOVA and Tukey HSD (p<0.05). The color difference (ΔE) between the resin specimens was also calculated. The L* values and b* values were significantly different between 6.5 and 8.5 mm specimens, and between 10.5 and 12.5 mm specimens. The a* values significantly differed among the various specimen sizes. The ΔE between pairs of various-sized specimens ranged from 0.3 to 2. The highest ΔE difference was observed between 6.5 mm and 12.5 mm specimens. CIE L*a*b* values of single-shade composite resin specimens were significantly different for various specimen sizes when measured with a colorimeter. Also, the color difference (ΔE) between pairs of various-sized specimens (ranging from 0.3 to 2) is indicative of perceptible differences among resin specimens. Therefore, when using a dental colorimeter, the specimen size of a composite resin needs to be carefully monitored for consistent CIE L*a*b* values.