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Objective: The aim of this study was to evaluate color compatibility of corresponding resin composite shades keyed to Vitapan Classical shade guide (Vita)., Method and Materials: Twenty-one shades of 6 commercial resin composites were analyzed. Specimens (n = 5) were made as disks, 11 mm in diameter and 2 mm thick, using cylindrical molds. Specimens were polymerized according to manufacturers' suggestions using a light-curing unit. Data were collected using a spectrophotometer and analyzed using the appropriate color difference metric equations. A total color difference (deltaE*ab) greater than or equal to 3.7 was considered a mismatch. Analysis of variance and Fisher's probable least-squares difference (PLSD) test. intervals for comparison of means were calculated at the .05 level of significance., Results: Mean deltaE*ab values among A2, B2, C2, and opaque A2 shade pairs were 4.4 (1.8), 7.3 (3.2), 5.6 (2.8), and 6.5 (1.8), respectively, while the mean color difference for all the pairs compared was 5.8 (2.8). For A2 shades, deltaL*, deltaa*ab, and deltab*ab values ranged by 5.3, 2.3, and 6.7, respectively. Corresponding values for B2 shades ranged by 10.5, 2.2, and 11.5; 7.9, 2.2, and 4.3 for C2 shades; and 7.9, 1.4, and 4.4 for opaque A2 shades. Fisher's PLSD critical intervals for comparing deltaE*ab values among the shades and composite pairs were 0.07 and 0.15, respectively (P < .0001, power 1.00)., Conclusion: Overall, poor color compatibility of shade pairs of identical shade designation was recorded. The best color match was recorded for A2 shade pairs, followed by C2, B2, and opaque A2 shade pairs.

Objectives: To evaluate the in vitro blending effect (BE) of layered resin composites related to material, shade, and differences in color and translucency between compared materials., Methods: Specimens made of two composites (2CS, n=5) consisted of the outer composite with an outer diameter of 10mm, 4mm thick and an inner diameter of 4mm, 2mm thick for the inner composite. Thus, the inner composite was encircled by a 3mm outer composite around its circumference and backed by a 2mm thick outer composite, to simulate a dental restoration surrounded by hard dental tissues. The outer composite was Palfique Estelite (PE, C2 shade, standard shade), while the inner composites were PE A2, B2 and C2 shades and corresponding shades of Point 4 (P4), Tetric Ceram (TC) and Filtek A110 (FA) composites (batch shades). Single-composite, disk-shaped specimens (1CS) of all five shades (D=10mm, 2mm thick, n=5) were made as well. Visual color assessments were done by six observers using a lightbooth and 1 (mismatch) to 5 (perfect match) scale. The BE was calculated as a difference in scores between corresponding 2CS and 1CS. Z-scores and corresponding BE values (BE(Z)) were calculated. 1CS were also evaluated using a spectrophotometer., Results: Blending effect ranged from -0.4 to 2.2, while BE(Z) ranged from -0.6 to 3.0. Mean visual scores for 1CS and 2CS were 1.8 (1.2) and 2.2 (1.3), respectively. BE increased with a decrease in color difference (r=0.41) and increase of translucency parameter (TP, r=0.77). High agreement was recorded among pairs of observers for both 1CS, r=0.95 (0.03) and 2CS, r=0.96 (0.02)., Significance: Blending effect is composite and shade dependent. Quantifying of blending potential of dental materials might provide useful clinical information for dental professionals.

Objective: It has been clinically observed that color differences between teeth and some restorations are smaller than if they are viewed in isolation. The objective was to evaluate in vitro the influence of restoration size, initial color difference and translucency on blending effect (BE) of resin composites., Methods: Specimens were made of two composites (2CS, n = 5). The outer ring (D=10 mm, 2-mm thick) was made of Palfique Estelite (PE, C2 shade), while the inner composites (D = 2-, 4-, and 6-mm, 2-mm thick) were PE and Esthet-X (EX, A2 and B2 shades of both materials). Single-composite specimens (1CS) of all five shades (D = 10 mm, 2-mm thick, n = 5, batch) were made as well. Visual color assessments were done by six observers using a 1-5 scale. The BE were calculated as a difference in visual scores between corresponding 2CS and 1CS. 1CS were additionally evaluated using a spectrophotometer (D55, 10 degrees). Intra-and inter-observer agreements were tested., Results: The blending effect for comparisons of PE/A2 for 2-, 4- and 6-mm inner composite was 2.7, 1.7, and 1.7, respectively. Lower values were recorded for PE/B2 (1.7, 1.2, and 1.1), EX/A2 (0.3), 0.0, and 0.1) and EX/B2 (-0.2, -0.1, and -0.1). The correlation coefficient (r) among BE for 2-, 4-, and 6-mm inner composite (2CS) and deltaE* among batch shades and PE/C2 (1CS) were 0.98, 0.95, and 0.97, respectively., Significance: Discovering and quantifying mechanisms of color shift of dental materials towards color of surrounding teeth may improve the esthetics of restorations and simplify shade matching.

The aim of this study was to evaluate polymerization-dependent changes in the color and translucency parameter (TP) of resin composites and to compare results obtained using two color-difference metric formulae, CIELAB and CIEDE 2000. Twenty-eight shades of commercial resin composites were analyzed. Specimens (n = 5) were made as discs, 11 mm in diameter and 2-mm thick, using cylindrical molds. Data were collected before and after composite polymerization, using a spectrophotometer. In regard to in vitro color changes of composites (DeltaE*) a DeltaE76 of 3.7 or greater was considered to be an unacceptable color change. Data were analyzed by analysis of variance, and Fisher's protected least significant difference (PLSD) intervals for comparison of means were calculated at the 0.05 level of significance. Mean polymerization-dependent differences in color were DeltaE00 = 4.48 (2.11) and DeltaE76 = 5.51 (2.68). The DeltaTP00 range was 2.57, while the DeltaTP76 range was 2.89. Mean polymerization-dependent differences in translucency were DeltaTP00 = 0.84 (0.77) and DeltaTP76 = 0.87 (0.76). Analysis of variance showed significant differences among composites, shades, and their interactions (P < 0.0001; power = 1.0). Regression equations and r values for the two color-difference formulae and all evaluated TP values showed very strong correlation. In conclusion, within the limitations of this study, polymerization-dependent changes in color and translucency were highly varied. The majority of shades showed polymerization-dependent differences in color higher than the DeltaE76 = 3.7. The TP generally increased after light polymerization by light activation. The very strong correlation (r > 0.97) between the two color-difference formulae indicates that the limitations of the CIELAB system do not appear to be a problem when evaluating composites; however, recorded differences between DeltaE76 and DeltaE00 values stress the importance of data conversion.