IADR Abstract Archives
Determining the color of glass-ceramic restorations with spectrophotometric examination
Objectives: To present day the aesthetics of prostheses is highly affected by the experience of the dental technician. The aim of this in vitro study is examine the optical effect of ceramics of different translucency and thickness, combined with substrates of different color. Such combination can be simulated using the world’s most advanced spectrophotometer in order to obtain reproducible, standardizable data.
Methods: A PerkinElmer ® LAMBDA 1050 UV/Vis/NIR Spectrophotometer was used in this study. Ceramic specimens were produced of Vita Suprinity (Vita Zahnfabrik) zirconia reinforced lithium silicate ceramic, shade A1, T (low translucency) and HT (high translucency), thickness range of 0.5mm to 2.5mm.
9 types of substrates were used: CoCr alloy, gold-colored alloy, zirconia, and 6 types of VITA SIMULATE.
3 shades of try-in pastes were used (Variolink Esthetic, Ivoclar). For the simulation of the cementation gap a metal plate was inserted between the substrates and the ceramic specimens.
The device measures the reflection spectrum by which the L*a*b values can be calculated. Averages were compared to the reference (1.5mm, T, neutral try-in paste, 2M3S substrate) with calculated ΔE value. Calculations were based on the CIEDE2000 formula.
Results: The ΔE value of lithium-silicate specimens were significantly affected by the shade of the substrate, the thickness of the specimen, translucency of the ceramic, however the cement shade effects were below the perceptibility threshold (ΔE 0.8). Significant relevance has been found between thickness and effect on shade, except for HT specimens of 2.0 and 2.5mm thickness.
Conclusions: The ΔE of the reference substrate is zero, proving the excellence and uniqueness of the measurement precision. The results also prove that a standardizable method has been developed. Other spectrophotometers currently used in dental practices cannot produce such results. For these reasons we shall continue the study in further depths.
Methods: A PerkinElmer ® LAMBDA 1050 UV/Vis/NIR Spectrophotometer was used in this study. Ceramic specimens were produced of Vita Suprinity (Vita Zahnfabrik) zirconia reinforced lithium silicate ceramic, shade A1, T (low translucency) and HT (high translucency), thickness range of 0.5mm to 2.5mm.
9 types of substrates were used: CoCr alloy, gold-colored alloy, zirconia, and 6 types of VITA SIMULATE.
3 shades of try-in pastes were used (Variolink Esthetic, Ivoclar). For the simulation of the cementation gap a metal plate was inserted between the substrates and the ceramic specimens.
The device measures the reflection spectrum by which the L*a*b values can be calculated. Averages were compared to the reference (1.5mm, T, neutral try-in paste, 2M3S substrate) with calculated ΔE value. Calculations were based on the CIEDE2000 formula.
Results: The ΔE value of lithium-silicate specimens were significantly affected by the shade of the substrate, the thickness of the specimen, translucency of the ceramic, however the cement shade effects were below the perceptibility threshold (ΔE 0.8). Significant relevance has been found between thickness and effect on shade, except for HT specimens of 2.0 and 2.5mm thickness.
Conclusions: The ΔE of the reference substrate is zero, proving the excellence and uniqueness of the measurement precision. The results also prove that a standardizable method has been developed. Other spectrophotometers currently used in dental practices cannot produce such results. For these reasons we shall continue the study in further depths.