Color Change Of Composite Resins Research Articles

Effect of finishing and polishing systems on the surface roughness and color change of composite resins.

BackgroundThis study is to examine the surface roughness and color changes occurring on composite resins following the application of different finishing and polishing systems. Material and MethodsIn our study, a total of 200 samples were prepared from composites resin (6×2 mm) containing supra-nano, submicron hybrid, nanohybrid, nano-ceramic and microhybrid filler. They were polished with diamond, aluminum oxide, silicon carbide finishing and polishing systems. The initial color values of composite samples were measured with a spectrophotometer and surface roughness values with a profilometer. After that, samples were immersed of coffee solution and color measurements were repeated on the 1st and 7th day. The differences between surface roughness (Ra) and color change values (∆Eab) were evaluated using two-way analysis of variance (ANOVA) test (p<0.05). ResultsFinishing and polishing systems produced a statistically significant difference between the surface roughness values of nano-ceramic, submicron hybrid and microhybrid composite resin samples (p<0.05). Supra nano composite, which showed the lowest surface roughness after all finishing and polishing systems, showed the least color change after 7 days compared to other composite groups (p<0.05). The microhybrid composite with the highest surface roughness was the most color changing composite group (p<0.5). ConclusionsThe spiral finishing and polishing system containing diamond particles was the system to provide the least color difference on all composite groups. However, color differences of all composite resin groups were found to exceed the perceptibility threshold (PT) and acceptability threshold (AT). Key words:Composite resin, color stability, surface roughness.

İlave Polisaj Uygulamasının Kompozit Rezinlerin Yüzey Pürüzlülüğü ve Renk Değişimine Etkisinin İncelenmesi

İlave Polisaj Uygulamasının Kompozit Rezinlerin Yüzey Pürüzlülüğü ve Renk Değişimine Etkisinin İncelenmesi

Influence of Light-curing Units on Surface Microhardness and Color Change of Composite Resins after Challenge

The aim of this study was to evaluate microhardness and color change (ΔE) of composite resins, light cured with different light emission diodes (LEDs) and submitted to artificial accelerated aging (AAA). Two composite resins with lucirin- TPO photoinitiator were selected: Tetric N-Ceram (Ivoclar Vivadent, A1) and Vit-l-escence (Ultradent, WO).A resin with the only camphorquinone photoinitiat or was chosen as a negative control: Filtek Z350XT (3M ESPE, WD). Disc-shaped specimens were prepared (5 mm diameter; 1.5 mm thick) and photopolymerized with an LED with one wavelength (Radii-Cal, SDI) or multiple wavelengths (Valo, Ultradent), for each composite resin (n = 10). Surface microhardness and color evaluations were performed immediately after specimen preparation and after AAA. Microhardness results were analyzed using Kruskal-Wallis and Mann-Whitney tests for multiple comparisons. To compare the evaluation of microhardness at different times, the Wilcoxon test was used. Mean values of ΔE, ΔL, Δa, and Δb were evaluated using two-way analysis of variance (ANOVA), and Tukey test for multiple comparisons (a = 0.05). Regarding microhardness, a statistically significant difference between the two LEDs was observed for Vit-lescence after AAA. When comparing composite resins that were light-cured with the same device, FiltekZ350XT obtained the greatest microhardness. All groups presented a statistically significant decrease in microhardness from the initial time to the AAA. Regarding ΔE, no statistically significant difference between the two LEDs was observed. When comparing composite resins, FiltekZ350XT showed the highest ΔE values. In general, an LED with multiple wavelengths influenced the microhardness of only one resin containing lucirin-TPO after AAA. The ΔE was more influenced by the composite resin than the LED device. The knowledge of composite resin with deficiencies in the polymerization mechanism could contribute to preventing restorations to become more susceptible to color change and reduction of the mechanical strength.

In Vitro Efficacy of Listerine Whitening Mouthwash for Color Recovery of Two Discolored Composite Resins.

Objectives:Color stability of composite resins has a significant role in their durability and clinical service. Considering the increasing use of composite resins and their gradual discoloration, this study aimed to assess the efficacy of Listerine whitening mouthwash for color recovery of two discolored composite resins.Materials and Methods:This in-vitro experimental study was performed on 20 samples fabricated of Filtek Z350XT (3M ESPE, St. Paul, MN, USA) and IPS Empress Direct (Ivoclar Vivadent, Schaan, Liechtenstein) composite resins. Primary colorimetry was performed using a spectrophotometer. The samples were immersed in a coffee drink for 7 days. They were then immersed in Listerine mouthwash for 4 minutes daily for 56 days. After this period, the color change of composite resins was reevaluated. Data were analyzed using repeated-measures analysis of variance (ANOVA) and t-test.Results:The primary color change of Z350XT after immersion in coffee was 1.6 times greater than that of IPS composite (P<0.0001). The color recovery of IPS and Z350XT after immersion in the mouthwash was 1.06±0.58 (P<0.01) and 2.58±1.65 (P<0.001) units, respectively. The color change of Z350XT after exposure to the mouthwash was 25% (1.4 times) greater than that of IPS (P<0.01).Conclusion:Both composite resins experienced a clinically unacceptable discoloration after exposure to coffee (ΔE>3.3). Filtek Z350XT showed greater color change than IPS. Use of Listerine whitening mouthwash caused significant color recovery in both composite resins.

Effects of Khat Extract and Other Staining Media on Color Change of Composite Resins Subjected to Various Polishing Methods

Abstract Objective: To assess the influence of Khat extract and other staining media on color changes in composite resins subjected to various polishing methods. Methods: 84 disk-shaped

Effect of 38%hydrogen peroxide agent on color change of composite resins stained with tea and coffee beverages (An in vitro study)

Background: The esthetic application of bleaching materials has gained popularity,with consequences for teeth and restorative materials. The purpose of this an invitro study was to investigate the effect of in-office bleaching agent (38%hydrogen peroxide) on the color change of three composite resins after stainingwith tea and coffee beverages.Materials and Methods: Sixty disc-shaped samples from three different compositeresins (Tetric Ceram, Tetric Flow and Tetric Evo Ceram) were used in this study.The samples of each group were randomly divided into two subgroups accordingto type of beverages (tea and coffee) used for staining of samples. After stainingof composite resins the total color change (ΔE1 ) was calculated usingspectrophotometer, then the samples immersed in WHITEsmile® office bleachingagent for 15 min x 3 times with a 7 days interval followed by ΔE2 calculation.Data were subjected to the ANOVA, LSD and student t-test at 0.05 significancelevel.Results: The results revealed that, there was clinically significant color change ΔE&gt;3.3 with a statistically highly significant differences (P=0.000) for all the groups.Coffee causes more discoloration than tea. After bleaching, the samples becamewhiter in color and only appreciable by skillful operator but considered clinicallyacceptable ΔE1 - ΔE2 &lt; 3.3.Conclusion: Tea and coffee beverages causes discoloration in composite but thiseffect was depended on the type of beverages and composite resins. The most ofcolor change occurred with Tetric Flow composite resin after immersion in coffeebeverage. The bleaching agent (38% hydrogen peroxide) can remove the stainingof composite resins and make its color clinically acceptable.

Color change of composite resins subjected to accelerated artificial aging

The aim of this study was to evaluate the influence of accelerated artificial aging (AAA) on the color change of composite resins used in dentistry. Three composite resins were evaluated: Two microhybrids and one hybrid of higher viscosity, with different amounts and sizes of filler particles, shades C2 and B2. A total of 54 specimens were obtained (18 for each composite resin), made of a Teflon matrix (15 mm in diameter and 2 mm in height). The color measurements were obtained with a Spectrophotometer, (PCB 6807 BYK Gardner) before and after AAA. Data were submitted to the Kolmogorov-Smirnov test (α >0.05), ANOVA and Tukey test (α <0.05). After statistical analysis, the color difference among composite resins with the same shades was analyzed. All composite resins showed unacceptable color changes after AAA (ΔE > 3). Considering the variable ∆E, it was observed that the color tone C2 was already statistically different for the microhybrid composite resin prior to AAA (P < 0.05) and in shade B2 for hybrid of higher viscosity and microhybrid with barium glass fluoride aluminum and silica dioxide (P < 0.01). After this process, a statistically significant difference was observed only for shade B2 between microhybrid composite resins (P < 0.01) and for hybrid of higher viscosity and microhybrid with barium glass fluoride aluminum and silica dioxide (P < 0.05). Regarding the color difference within a same composite resin group, before aging the composite resin hybrid of higher viscosity B2 showed the highest color variation rate and microhybrid with zirconium/silica C2 showed the lowest. All composite resins presented unacceptable color changes after 382 h of aging and different composite resins with same hue, presented different colors before being subjected to the aging process (B2 and C2) and after (B2). It was also observed color difference within a group of the same composite resin and same hue.

Effects of fibers on the color change and stability of resin composites after accelerated aging

Composite resins were reinforced with glass and polyethylene fibers in this study, and the effect of fiber reinforcement on the color change of composite resins was investigated. After accelerated aging, the effect of fiber reinforcement on the color stability of composite resins was also examined. There were three experimental groups (n=12 disks per group): non-fiber-reinforced composite (non-FRC control), polyethylene fiber (Ribbond-THM)-reinforced composite, and glass fiber (everstick NET)-reinforced composite. According to the critical remarks of color change of National Bureau of Standarts (NSB), glass fiber-reinforced anterior composites showed trace color change and polyethylene-fiber reinforced composites showed slight color change before accelerated aging. After accelerated aging, both control and fiber-reinforced composite groups showed noticeable color change. It was concluded that both the types of fiber reinforcement and composite resin influenced the color change of fiber-reinforced composite resins.

The effect of polishing techniques on the surface roughness and color change of composite resins

Surface characteristics may affect the color change and surface roughness of composite resins. This study evaluated the surface roughness and color change of a hybrid, a microhybrid, and a nanohybrid composite resin polished with the use of polishing discs, wheels, and a glaze material. Fifty discs (10 x 2 mm) were fabricated for each composite resin (nanohybrid, Grandio; microhybrid, Filtek Z250; hybrid, Quadrant Universal LC) for a total of 150 discs, prepared using polyester strips and divided into 5 groups of 10. One of the groups served as control (C) and had no surface treatment (n=10). The specimens of the experimental groups were ground with 1000-grit silicon carbide paper. In 4 experimental groups (n=10), specimen surfaces were polished with polishing discs (D) (Sof-Lex), with polishing wheels (W) (Astropol), with polishing discs preceding the glaze application (DG) (Biscover), or with polishing wheels preceding the glaze application (WG), respectively. Color was assessed using a small area colorimeter. The color differences (DeltaE) values between the specimens of Group C and the experimental groups were calculated, and the data were compared using 2-way analysis of variance (ANOVA) (alpha=.05). Subsequently, the surface roughness (Ra) of the specimens was evaluated using a profilometer, and the data were analyzed by 2-way ANOVA followed by a Tukey multiple comparisons test (alpha=.05). The polishing technique and type of composite resin significantly affected the Ra and DeltaE values of the composite resins (P<.001). While the use of polishing wheels produced the highest Ra values when compared to the other polishing techniques (P<.001), the nanohybrid composite resin showed the lowest Ra values compared to the other composite resins in the control groups (P<.001). All of the nanohybrid and microhybrid composite resin groups were found to be significantly different from each other in terms of color difference (P<.001). The highest Ra values were obtained with hybrid composite resins due to the size of the filler particles that were exposed after polishing. Although the smoothest surfaces were obtained with polyester strips, the use of glaze material after polishing discs or polishing wheels resulted in significantly lower Ra and DeltaE values than the use of the latter alone. The glaze appears to fill the structural microdefects and provide a more uniform, regular surface.

Rare Earth Oxide-containing Fluorescent Glass Filler for Composite Resin

In recent dental care, esthetic restorative materials such as composite resin and porcelain have been widely used and studied. However, their good esthetics makes the visual inspection of restored teeth difficult. In this study, a fluorescent glass filler containing rare earth oxides - which are well-known fluorescent materials - was prepared and used in composite resin to enhance visual inspection capability with small change in color. For example, when irradiated with near ultraviolet light, an Eu2O3-containing filler fluoresced clearly and visibly. The fluorescence intensity of the prepared composite resin increased with increase of Eu2O3 content in the glass filler and with filler/resin ratio in the resin. Despite the clear fluorescence, the effect of Eu2O3 on the color change of composite resin was quite small - even when up to 10 wt% Eu2O3 was added to the glass filler. Tb4O(7-) and Dy2O3-added fillers also showed clear fluorescence, just like Eu2O3-added filler. Therefore, fluorescent glass fillers for composite resins, resulting in small color change in the latter, were successfully prepared in this study.

Composite resin color change after vital tooth bleaching

Color change of composite resin was determined with the Minolta Chroma meter (CR-100) after four sessions of vital bleaching. Specimens of selected composite resin materials were subjected to vital bleaching (37% H 3PO 4/1 minute, then 30% H 20 2/infrared light/30 minutes.) Specimens were stored in water between bleaching. Control specimens were used to determine the effects of water storage alone. Initial L *a *b * color readings were made on 24-hour hydrated specimens. Final L *a *b * readings were made on 24-hour hydrated specimens. Calculations were made for the A E values for each specimen. Mean Δ E values and standard deviations were obtained for each material. Two-way ANOVA and Newman-Keuls analyses showed significant (α = 0.05) color change for most bleached materials. Additionally, some materials had Δ E values greater than 3. These were visibly lighter compared to their controls. Vital bleaching produced color change in most composites as measured with the Chroma meter. This technique may be used to lighten dark-colored or stained composite resin restorations.