Effect of Bleaching on Color Change and Refractive Index of Dental Composite Resins

Department of Endodontics, Faculty of Dentistry, Cumhuriyet University, Sivas, Turkey.
Dental Materials Journal (Impact Factor: 0.97). 02/2008; 27(1):105-16. DOI: 10.4012/dmj.27.105
Source: PubMed


This study investigated the effects of three bleaching agents (Whiteness Perfect, Whiteness Super, and Whiteness HP) on the color change and refractive index of three dental composites (Admira, Durafill VS, and Gradia Direct). Twenty disk-shaped specimens (10 x 2 mm) of each composite were prepared and divided into four subgroups (n=5). An unbleached group was used as a control, while the remaining specimens in the three subgroups were bleached with one of the bleaching agents respectively. Color change was assessed according to CIELAB color system and refractive indices were determined by phase modulated spectroscopic ellipsometry. Color differences between bleaching and baseline value (DeltaE) were less than 3.3 for all groups. However, bleaching with Whiteness HP led to noticeable color changes for Admira and Durafill VS. While this agent had no effect on the refractive indices of these composites, the other two agents containing carbamide peroxide increased their refractive indices. Therefore, results suggested that replacement of such composite restorations may be required after bleaching.

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Available from: Giray Bolayır, Mar 16, 2014
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    • "Different concentrations of hydrogen peroxide have been used in bleaching procedures [13]. Studies concerning the interaction between composite restorations and bleaching materials have extensively evaluated the bond strength of adhesives to enamel and dentin after bleaching [14, 15], effect of bleaching agents on surface texture, hardness and roughness [16–19], and color and microleakage of dental composites [20]. "
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    ABSTRACT: Objective: The aim of this study was to assess the effect of bleaching on elution of monomers from nanofilled and microhybrid composites. Materials and Methods: 80 samples (5mm diameter and 3mm thickness) of each composite were prepared. After curing, half of them were randomly polished. Each group was divided into 8 subgroups and immersed in water or 10%, 20% and 30% H2O2 for 3 or 8 hours. Eluted Bis-GMA (Bis-phenol A Glycidyl Dimethacrylate), TEGDMA (Triethyleneglycol Dimethacrylate), UDMA (Urethane Dimethacrylate) and BisEMA (Bis-phenol A ethoxylate Dimethacrylate) were quantified by high performance liquid chromatography and the results were analyzed by univariate ANOVA and t-test (P<0.05). Results: Bleach significantly increased the overall release of monomers (P<0.001); TEGDMA was released more than Bis-GMA (P<0.001). Supreme released more TEGDMA compared to Z250 (P<0.001). Bleaching increased the release of this monomer (P<0.001). Increasing both the concentration of H2O2, and the immersion time, increased the release of TEGDMA (P<0.001). Polishing had no effect on release of this monomer (P=0.952). Supreme released more Bis-GMA than Z250 (P=0.000). The more concentrated H2O2 caused more elution of Bis-GMA (P= 0.003); while the effect of immersion time was not significant (P=0.824). Polishing increased the release of Bis-GMA (P=0.001). Neither the type of composite nor Bleaching had any effect on release of UDMA (P=0.972) and (P=0.811) respectively. Immersion duration increased the release of UDMA (P=0.002), as well as polishing (P=0.024). Conclusion: Bleaching increased the release of monomers. Nanofilled composites released more monomer than the microfilled.
    Full-text · Article · Jan 2014
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    • "In other words, it has a lower resin content compared to Heliomolar composite resin. As it was previously pointed out, hydrogen peroxide is a strong oxidative agent, which can destroy the resin matrix of composite resin and induce discolorations by influencing their amine and unsaturated components (8). Since the microfilled composite resin has a higher resin content compared to giomer, it may be more susceptible to discoloration in the longer term. "
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    ABSTRACT: Objectives: The effect of 15% carbamide peroxide bleaching gel on color stability and surface topography of a giomer and a microfilled composite resin was evaluated in the present in vitro study. Study design: Forty discs measuring 10 mm in diameter and 1 mm in thickness were prepared from a giomer and a microfilled composite resin. Each material yielded 20 discs with completely smooth surfaces. Then a spectrophotometer was used to measure L* (lightness), a* (redness, greenness) and b* (blueness, yellowness) color coordinates of all the discs. Subsequently, the specimens were subjected to 15% carbamide peroxide bleaching gel. After measuring the color coordinates once again, color changes (ΔE*) were calculated by the CIELAB system. Six specimens from each material (three specimens before bleaching agent application and three specimens thereafter) were viewed under an atomic force microscope (AFM) for surface topography evaluation. Data were analyzed by Mann-Whitney U and Kruskal-Wallis tests at α=0.05. Results: There were no statistically significant differences in color changes (ΔE*) between the two materials (P>0.05). In addition, no significant differences were detected in surface roughness between composite resin and giomer discs before and after bleaching (P>0.05 for both). However, in both materials the differences in surface roughness were significant before and after bleaching procedures (P<0.001). Conclusions: Based on the results of the present study it was concluded that 15% carbamide peroxide does not induce clinically detectable color changes in composite resin and giomer despite an increase in surface roughness. Key words:Bleaching, color stability, giomer, microfilled composite.
    Full-text · Article · Aug 2012 · Medicina oral, patologia oral y cirugia bucal
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    • "The color change of composite resins after bleaching was probably due to superficial cleansing of the specimens. The results of previous studies as well as this study indicate that the color change induced by the bleaching agent might be dependent upon the monomer structure, and volume of the resin matrix as well as the filler systems of composite materials [42]. "
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    ABSTRACT: This study was conducted to determine the effect of 15% carbamide peroxide bleaching agent on color change and surface topography of different composite veneering materials (Filtek Z350 (3M ESPE), Esthet X (Dentsply India), and Admira (Voco, Germany). Methods. 30 samples were fabricated for evaluation of color change using CIELAB color system and Gonioreflectometer (GK 311/M, ZEISS). 45 disc-shaped specimens were made for evaluation of surface topography after bleaching (Nupro White Gold; Dentsply) using SEM. Statistical analysis. One way ANOVA and Multiple comparison tests were used to analyze the data. Statistical significance was declared if the P value was .05 or less. Results and conclusion. All the specimens showed significant discoloration (ΔE > 3.3) after their immersion in solutions representing food and beverages. The total color change after bleaching as compared to baseline color was significant in Filtek Z350 (P = .000) and Esthet X (P = .002), while it was insignificant for Admira (P = .18). Esthet X showed maximum surface roughness followed by Admira and Filtek Z350. Bleaching was effective in reducing the discoloration to a clinically acceptable value in all the three groups (ΔE < 3.3).
    Full-text · Article · Dec 2010 · International Journal of Dentistry
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