ABSTRACT
Color is an important parameter and indicator in esthetic dentistry. High Refractive Index (HRi) composite resins have different optical properties than general resin composites. The refractive index of composite resin shows how the light propagates through that medium. With proper anatomic layering techniques of enamel and dentin, composite resin materials have optical properties that resemble natural teeth. This study aims to analyze the effect of HRi enamel and dentin layer thickness to L*a*b* value in CIELAB system. Specimens were fabricated using combinations of enamel composite resin layer thicknesses of 0.5 mm and 1 mm combined with dentin composite resin layer thicknesses of 1 mm and 2 mm. Four test groups were obtained with 21 samples for each group. Digital images were obtained using a digital camera, 100 mm macro lens, and a ring flash equipped with a polarizing filter and analyzed using the eLABor_aid technique to assess L*a*b* value. Independent t-test showed a significant difference in L*a*b* value between the HRi enamel composite group of 0.5 mm and 1 mm in thickness which was combined with both 1 mm and 2 mm of dentin layer thickness (p<0.01). Group testing with different dentin composite layer thicknesses which was combined with 0.5 mm HRi enamel composite layer showed a significant L*a*b* value difference (p<0.05). Combination with 1 mm HRi enamel composite thickness showed a significant difference in the a* and b* values (p<0.01) but no significant difference for the L* value (p = 0.15). HRi enamel and dentin layer thickness affect the L*a*b* value on the CIELAB system.
