Discoloration Of Composites Research Articles

Effect of different polishing systems on composite discoloration

Effect of different polishing systems on composite discoloration

Staining Susceptibility of Microhybrid and Nanohybrid Composites on Exposure to Different Color Solutions

Composite discoloration is considered one of the most significant disadvantages of dental restorations. The purpose of our study was to assess the color susceptibility of two esthetic composite filling materials, microhybrid composite (ValuxTM Plus) and nanohybrid composite (FiltekTM Z250 XT), to different solutions and compare the results among different measuring methods (Intraoral scanner, Easyshade spectrophotometer, and Vita classical shade guide). A total of 100 specimens were fabricated in this experimental study. Each sample was soaked in either Coca-Cola, orange juice, tea, coffee, or distilled water for 30 days. Color measurement was performed using the spectrophotometer, IOS 3Shape Trios, and Vita classical shade guide. L*a*b* values were recorded to determine the color changing (ΔE00). The significance level was p < 0.05. All samples showed clinically visible color changes after immersion in coffee, tea, orange juice, and Coca-Cola. The nanohybrid composite showed high color change when placed in tea (ΔE00 = 12.5) measured by the Intraoral scanner, spectrophotometer (ΔE00 = 23.21), and by Vita classical shade guide (ΔE00 = 25). Less color discoloration was perceptible in the microhybrid composite when immersed in Coca-Cola (ΔE00 = 1.78) measured by spectrophotometer, intraoral scanner (ΔE00 = 2.85), and measured by Vita classical shade (ΔE00 = 3.2). The results showed that measurements with the spectrophotometer and Vita classical shade guide were correlated. The results were analyzed using the chi-square and Wilcoxon signed-rank tests, and there was a significant difference (p < 0.001) in both composite resins for all the solutions, with microhybrid being more color stable. Microhybrid composite had more color stability than nanohybrid composite, especially when immersed in tea and coffee. The spectrophotometer with Vita classical shade guide showed better interrater agreement than with the intraoral scanner.

DISCOLORATION OF NANOHYBRID AND NANOFILLER RESIN COMPOSITES AFTER EXPOSURE TO TURMERIC

Background: Recently, the demand of aesthetic restorative has greatly increased and enchourages the development of composite resin material. The latest technology of composite is nanohybrid and nanofiller composites. However, color stability of nanohybrid and nanofiller resin composites can be influence by intrinscic and (or) extrinsic factor. Intrinsic factor depends on the composition on the resin composite and extrinsic factor such as colored food and beverages. Turmeric as a food ingredients, that is often consumed by Indonesians can cause discoloration in composites, because it contains the active pigment curcuminoid. The discoloration of nanohybrid and nanofilles composites can caused by the process of water sorbstion and curcumin particles. Purpose: Explain the discoloration of nanohybrid and nanofiller resin composites after exposure to turmeric and the factor that influence. Review(s): The reaction between the curcumin contained in turmeric and nanohybrid as well as nanofiller composites can cause discoloration in both composites. One of the reasons behind the discoloration on composite resin is that the composite resin can absorb water and its substances are carried by the water. Discoloration of composites was influence by the concentration of turmeric solution, pH of the solution, finishing and polishing process, temperature, time of exposure, composition of filler and matrix. Conclusion: Turmeric as an extrinsic factor can cause color changes in nanohybrid and nanofiller composites (ΔE>3,3), where the level of color change can be obtained by intrinsic factors, such as composition of filler and matrix, and other extrinsic factors.

Influences of Different Air-Inhibition Coatings on Monomer Release, Microhardness, and Color Stability of Two Composite Materials.

The aim of this study was to evaluate the effect of light-curing protocols on two modern resin composites using different air-inhibition coating strategies. This was accomplished by assessing the amount of monomer elution, surface microhardness, and composite discoloration in different storage conditions. A total of 120 specimens were prepared using Filtek Supreme XTE (3M ESPE, Seefeld, Germany) and CeramX Universal (Dentsply DeTrey, Konstanz, Germany). Specimens were light-cured in air as per manufacturer's instructions or in the absence of oxygen. This latter condition was achieved using three different approaches: (i) transparent polyester strip; (ii) glycerin; (iii) argon gas. Specimens were assessed for release of monomers, Vickers hardness, and discoloration after storage in different solutions. The results were analyzed with ANOVA one-way test followed by Student-Newman-Keuls test. Moreover, multiple comparisons of means were performed using the Student t-test (p<0.05). The amount of monomers released from the tested specimens was very low in all conditions. The presence of oxygen induced some decrease in microhardness. The highest discoloration values, for both materials, were obtained after ageing in red wine. In case finish and polish procedures are awkward to achieve in posteriors composite restoration, light-curing in the absence of oxygen should be considered, especially when performing composite restoration in esthetic areas.

Discoloration of resin based composites in natural juices and energy drinks

Background/Aim. Discoloration of dental restorations makes them aesthetically unacceptable and is a frequent reason for replacement of composite restorations. The aim of this study was to evaluate changes of color and fluorescence of resin-based composites (RBCs) exposed to natural juices and energy drinks. Methods. Microhybrid composite Gradia DirectTM Extra Bleach White disc-shaped specimens (n = 35) were immersed in three different natural juices and four different energy drinks. Absorption spectra of natural juices and energy drinks, diffuse reflection and fluorescence of composite samples were measured prior and after seven- day immersion by spectrophotometer Thermo Evolution 600 and spectrofluorometer Fluorolog-3-221. Composite?s color was calculated from diffuse reflection spectra and expressed in CIELAB color space (Commission International de l?Eclairage). Results. All natural juices and energy drinks induced color change of resin based composites, but to the different extent. Only aronia and carrot juices induced total color change considerably higher than clinically acceptable threshold, 9.3 and 6.2, respectively. All energy drinks and aronia juice induced notable decrease in fluorescence; the highest change of 28% was evidenced in the case of aronia juice. Conclusion. Change of color and fluorescence will appear differently with various solutions due to different chemical composition and concentration of colorant species in different beverages. Solutions with higher optical absorption induced higher total color change. Discoloration of composites in aronia and carrot juices is similar to those earlier reported for red wine, tea and coffee.

The effect of curing time and immersion solutions on discoloration of hybrid composites and nanocomposites

Objectives: The purpose of this study was to evaluate the color change of six esthetic dental composite materials immersed in various solutions for 7 days, and determine the effect of curing time on color change. Materials and Methods: Disk-shaped samples of six types of light curing composite were prepared, and all samples were divided into two groups that were light cured for 20 s and 40 s (n = 7). After 24 h, color measurements were performed with a digital spectrophotometer. Samples were immersed in a solution (coffee, tea, Coke; , cherry juice and distilled water) for 7 days. The discoloration of each specimen was measured and statistically analyzed with a statistics software SPSS Version 17.0 (Released 2008. SPSS Statistics for Windows, Chicago: SPSS Inc.). Results: The discoloration of Filtek™ and Ceram.X was significant. The highest color change values were in Filtek™ group. The lowest color change values were in Herculite classic group. Coffee (ΔE = 12.27) showed the highest influence on color change. There was no effect of curing time on the discoloration of the composites. Significance: The color differences (ΔE) ranged from 3.23 to 12.48. There was no significant difference in color change between two curing times, and coffee was the immersion medium that promoted the highest color change on the tested composite resin.

Effects of UV weathering on surface properties of polypropylene composites reinforced with wood flour, lignin, and cellulose

In this study, the influence of accelerated weathering on polypropylene composites reinforced with wood flour (WF), lignin, and cellulose at different loading levels were evaluated. Six groups of samples were exposed in a QUV accelerated weathering tester for a total of 960h. The surface color, surface gloss, contact angle and flexural properties of the samples were tested. Besides, the weathered surface was characterized by SEM and ATR-FTIR. The results revealed that (1) the discoloration of composites was accelerated by the presence of lignin, especially at high content; (2) composites containing lignin showed less loss of flexural strength and modulus, less cracks, and better hydrophobicity on weathered surface than other groups, confirming its functions of stabilization and antioxidation; (3) cellulose-based composites exhibited better color stability but more significant deterioration in flexural properties after weathering compared to other composites, suggesting that such kind of composites could not be used as load-bearing structure in outdoor applications.

Ultraviolet weathering of HDPE/wood-flour composites coextruded with a clear HDPE cap layer

This study examined the effect coextruding a clear HDPE cap layer onto HDPE/wood-flour composites has on the discoloration of coextruded composites exposed to accelerated UV tests. Chroma meter, FTIR-ATR, XPS, SEM, and UV vis measurements accounted for the analysis of discoloration, functional groups, and degree of oxidation of both uncapped (control) and coextruded composites before and after UV exposures. Two separate discoloration characteristics occurred in the discoloration of composites. For uncapped WPCs (control), chemical changes due to photooxidation resulted in darkening followed by physical changes, including loss of colored wood components from the surface, as well as increased roughness on the surface, which led to lightening of WPCs. By contrast, because a hydrophobic cap layer prevented the loss of colored components from the surface, coextruding a clear hydrophobic HDPE cap layer over WPCs significantly decreased the discoloration during the weathering process. Photooxidation of wood components at the interface accounted for the discoloration of coextruded WPCs before the failure of cap layer. Moreover, as the cap layer absorbed a specified amount of UV light and reduced oxygen available to interface, it decreased the photooxidation rate at the interface compared to that at the WPCs surface.

Small cross-sectional survey of composite restoration attributes associated with choices for replacement

The aim of this work was to present a small cross-sectional survey of composite restoration clinical attributes associated with choices for replacement. Ninety-four composite fillings selected to be replaced were included in this study. A questionnaire was filled out after each procedure in order to assess the clinical conditions that indicated the restoration replacement (marginal staining, unsatisfactory restoration anatomy, marginal fracture, fractured restoration body, painful symptoms, dental fracture, composite discoloration and/or restoration displacement). These conditions could be combined. The chi-square and Exact Fisher tests were performed to analyze the different variables (p < 0.05). The results showed that composite shade discoloration was the main cause of restoration replacement (63.8%). Marginal staining (50%), unsatisfactory restoration anatomy (50%), marginal fracture (14.9%), painful symptoms (8.5%), fractured restoration body (4.3%), dental fracture (1.1%) and total displacement of the restoration (1.1%) were conditions that could be associated. The main cause of dental composite restoration replacement was material shade mismatch with the dental structure (anterior teeth) or marginal staining and unsatisfactory restoration shape (posterior teeth). Marginal staining and composite shade discoloration contrasting with dental structure were related to the presence of caries.