The effects of different repolishing procedures on the color change of bulk-fill resin composites.

Purpose: The purpose of the study was to investigate the impact of repolishing procedures on the color change of bulk-fill resin composites after being exposed to coffee. Materials and methods: Four bulk-fill resin composites (Filtek One bulk-fill, Tetric EvoCeram bulk-fill, Admira Fusion x-tra bulk-fill, Grandio SO x-tra bulk-fill) were tested. Sixty samples were prepared with each resin composite and were randomly divided into two groups: first one received the one-step polishing system (Optragloss) and the other group received the two-step polishing system (Nova Twist) (n=30). After being kept in coffee for 12 days, the samples were divided into three subgroups according to repolishing: one-step repolishing group, two-step repolishing group, and non-repolishing group (n=10 for each). Color measurements of the resin composite samples were determined with a spectrophotometer. The difference in color change was calculated using the CIEDE 2000 color formula. The data were analyzed using three-way ANOVA and Tukey test. Results: Among composite materials, Filtek One bulk-fill (1.84 ± 0.98) less color change was observed compared to others (p<0.001). In terms of polishing systems, Optragloss (2.96 ± 1.51) showed significantly greater color change than Nova Twist (2.21 ± 1.07) (p<0.001). The non-repolishing group (3.78 ± 1.25) presented significantly greater color change than the Nova Twist sytem (1.49 ± 0.61) and Optragloss system (2.50 ± 1.01) (p<0.001). Conclusion: The repolishing process reduced discoloration. A two-step repolishing system results in less color change compared to a one-step repolishing application. In polishing systems containing diamond particles, increasing the number of steps can contribute to color stability.

Effect of aging and fiber-reinforcement on color stability, translucency, and microhardness of single-shade resin composites versus multi-shade resin composite.

OBJECTIVE: The purpose of this study was to evaluate the effect of aging and fiber-reinforcement on the color stability, translucency, and microhardness of single-shade resin composites versus multi-shade resin composite. MATERIALS AND METHODS: Four resin composites (Filtek Z250, Omnichroma, Vittra APS Unique, Zenchroma) were tested. Three subgroups of specimens were prepared for each of the composites: control, polyethylene fiber-reinforcement, and glass fiber-reinforcement- groups (n = 10/per group). The samples were subjected to aging for 10,000 thermal cycles. Color differences (ΔE00 ) were calculated after aging. Relative translucency parameter (RTP00 ) and microhardness values were calculated before and after aging. A two-way analysis of variance and the generalized linear model was used (p < 0.05). RESULTS: The lowest and highest ΔE00 values were found for Filtek Z250 (0.6 ± 0.2) and Omnichroma resin composites (1.6 ± 0.4), respectively. The ΔE00 value of the polyethylene fiber-reinforcement group (1.2 ± 0.6) was significantly higher than the ΔE00 value of the glass fiber-reinforcement group (1.0 ± 0.4, p < 0.001). The RTP00 value of the glass fiber-reinforcement group (1.92 ± 0.78) was significantly higher than the RTP00 value of the polyethylene fiber-reinforcement group (1.72 ± 0.77, p < 0.001). The highest microhardness values were found in glass fiber-reinforcement group (76.48 ± 17.07, p < 0.001). CONCLUSION: Single-shade resin composites were more translucent, had higher color change, and lower hardness than multi-shade resin composite. For relative translucency and microhardness, statistical significance was found in the material and fiber type interaction. The glass fiber-reinforcement provided higher translucency, lower color change and higher microhardness values than polyethylene fiber-reinforcement group after aging. Thermocycling had a significant impact on the color stability, translucency parameter, and microhardness of the tested resin composite materials. CLINICAL SIGNIFICANCE: Single-shade resin composite materials have greater color-changing potential. The glass fiber-reinforcement optimize resin material mechanical properties and color stability more than polyethylene fiber-reinforcement.

Do universal adhesive systems affect color coordinates and color change of single-shade resin composites compared with a multi-shade composite?

The objective of the study was the impact of universal adhesives on color coordinates and color change of single-shade resin composites compared with a multi-shade composite after thermocycling. Five resin composites (Filtek Z250, Omnichroma, Vittra APS Unique, Zenchroma, and Charisma Diamond One) were used. The composites were randomly divided into three subgroups: two universal adhesive groups (Single Bond and Gluma Bond) and one control group (n=10). Color measurements were performed initially and after 10,000 thermocycling. Color change (ΔE00) values were calculated using the CIEDE2000 formula. The two-way variance analysis was used (p<0.05). The lowest and highest ΔE00 were exhibited in the Filtek Z250 and Charisma Diamond One (p<0.001, p<0.001, respectively). The highest ΔE00 was exhibited in the Gluma Bond (p<0.001). An adhesive system may adversely affect the color change of resin composite materials. L and a values of resin composites decreased, and the b values increased after thermocycling.

Effect of whitening mouthrinses on color change, whiteness change, surface roughness, and hardness of stained resin composites.

PURPOSE: To evaluate the effect of whitening mouthrinses on the color change, whiteness change, surface roughness, and hardness of stained resin composites after different immersion times. METHODS: Three different resin composites (Estelite Σ Quick, G-Aenial Anterior, Omnichroma) were used to prepare a total of 90 samples (30 samples from each resin composite). The samples were kept in coffee for 12 days, then divided into three subgroups (Control, Crest 3D White, and Listerine Advanced White; n=10 each). Color change (ΔE00) and whiteness change (ΔWID) were evaluated at time intervals of 0-24 hours (T0-T1), 0-72 hours (T0-T2), and 24-72 hours (T1-T2). Surface roughness and hardness values were evaluated at T0, T1, and T2 after immersion in mouthrinses. Two-way ANOVA (for color and whiteness changes) and generalized linear model (for surface roughness and hardness) were used for data analyses (P< 0.05). RESULTS: Omnichroma had the highest value for color change with Crest 3D White during T0-T1 and T0-T2. Crest 3D White showed better color changes than Listerine Advanced White. In all composites and mouthrinse groups, the highest and lowest values of ΔWID were at T0-T2 and T1-T2, respectively, with the highest value for Omnichroma with Crest 3D White at T0-T2 and the lowest for G-Aenial Anterior with control groups at T1-T2. The highest roughness values were found with the Omnichroma at T2. Whitening mouthrinses significantly increased roughness and decreased hardness compared to baseline. CLINICAL SIGNIFICANCE: Short-term regular use of whitening mouthrinse can recover color and increase the perception of whiteness without any significant increase in the roughness or hardness of resin composites, while long-term use affects both the roughness and hardness of resin composites.

Accelerated Aging Effects on Color Change, Translucency Parameter, and Surface Hardness of Resin Composites.

Background: The aging process can induce a change in the surface microstructure of materials, the chemical compositions of matrices, and the filler particles of resin composites. This study is aimed at evaluating the effects of accelerated artificial aging (AAA) on the color change, translucency parameter (TP), and surface hardness of resin composites. Methods: Five resin composite materials (Tetric N-Ceram, Filtek Z250, Charisma Smart, Herculite Classic, and Escom100) were evaluated. A spectrophotometer was used for color measurements (L∗, a∗, and b∗). TP and color changes (ΔE 00) were calculated using the CIEDE2000 formula. The resin materials were subjected to aging for 300 hours. The hardness and TP values were measured before and after AAA. One- and two-way ANOVA and the Tukey test were used. The significance level was accepted as p < 0.05. Results: Escom100 had significantly higher ΔE 00 values than the other resin composites, and Charisma Smart had significantly lower ΔE 00 values than the other tested materials (p < 0.05). Before and after AAA, Charisma Smart had the lowest TP values, and Filtek Z250 exhibited the highest hardness values (p < 0.05). For TP and surface hardness, the effect size value of the composite material was found to be higher than that of AAA. Conclusions: After AAA, the investigated resin composites had ΔE 00 values that were above clinically acceptable thresholds. After aging, the tested materials generally exhibited decreases in L∗ values and a∗ values, while increases in b∗ values were observed. The ΔTP values of the resin composites were similar. AAA significantly increased the surface hardness of the tested materials.