Resin composite thickness' influence on L*a*b* coordinates and translucency

Objectives To evaluate if material thickness can influence the L*a*b* coordinates and translucency of different composite shades. Materials and methods Twelve composite disc specimens made of three different resin composite materials (dentin A2, Essentia, GC; body shade A2, Brillant Everglow, Coltene-Whaledent; enamel skin neutral, Inspiro, Edelweiss DR) and of three different thicknesses 0.5, 1.0, and 1.5 mm were readied. L*a*b* coordinates of the 118 specimens were assessed by a calibrated reflectance spectrophotometer over a black as well as a white background. Results Over the black background, median ΔE00 values varied from 0.7 (Brilliant Everglow) to 1.5 (Inspiro SN) for 0.5-mm composite thickness (intrinsic color variation) and from 3.2 (Essentia) to 7.5 (Inspiro SN) for 1.0 mm, respectively 6.1 (Essentia) to 11.1 (Inspiro SN) for 1.5-mm composite thickness (color variation related to thickness). Over the white background, median ΔE00 values varied from 0.6 (Essentia) to 1.6 (Inspiro SN) for 0.5-mm composite thickness and from 2.9 (Inspiro SN) to 4.3 (Essentia) for 1.0 mm, respectively 4.9 (Inspiro SN) to 7.0 (Essentia) for 1.5-mm composite thickness. Transparency varied from 25.2% (Essentia) to 34.6% (Inspiro SN) for 0.5-mm composite thickness, from 20.3% (Essentia) to 27.5% (Inspiro SN) for 1.0-mm thickness and from 14.8% (Essentia) to 22.9% (Inspiro SN) for 1.5-mm thickness. Conclusions Material thickness can influence the L*a*b* coordinates and translucency of different composite shades. Clinical relevance L* a* b* coordinates are influenced by composite thickness.