Background and Aim: Discoloration is among the most common problems of composite restorations. Color change over time compromises the main advantage of composite resins namely their high esthetics. In such cases, the restoration needs to be replaced. .The aim of this in-vitro study was to evaluate the effect of accelerated artificial aging (AAA) on the color stability of three composite resins (Filtek Z250, Filtek Z250XT, and Filtek Supreme). Materials and Methods: In this experimental study, 7 composite specimens with equal dimensions were fabricated of each composite resin. The initial color of specimens was measured using a spectroradiometer according to the CIE L*a*b* system. The specimens were then submitted to AAA for 384h and underwent color assessment again. Before and after aging, the surface roughness of one specimen from each group was determined by Atomic Force Microscopy (AFM). The obtained color parameters were analyzed by one-way ANOVA and Tukey’s test. Results: The color change of Filtek Z250 was significantly lower than that of Filtek Z250XT and Filtek Supreme (P≤0.05). No statistically significant differences were found between Z250XT and Supreme in this respect (P>0.05 ). Conclusion: All composite resins showed color change above the clinically acceptable threshold. Z250 microhybrid composite was more color stable than nano-composites (Z250XT and Supreme). AAA increased the surface roughness in all groups but it was within the clinically acceptable range.

Background and Aims: The purpose of this in vitro study was to assess the effect of two different surface treatments on the contrast ratio of IPS Emax press ceramic submitted to accelerated aging.Materials and Methods: Ten ceramic (IPS Emax press) disks (10-mm diameter and 1.5-mm thick) were fabricated according to the manufacturer’s recommendations. The samples were randomly divided into 2 groups (n=5): polishing and glazing. Contrast ratio ware obtained with a spectrophotometer before and after accelerated aging. The contrast ratio (CR=Yb/Yw), defined as the ratio of illuminance (Y) of the test material when it is placed on the black background (Yb) to the illuminance of the same material when it is placed over a white background (Yw), was determined. The data were statistically analyzed by two-way analysis of variance (P<0.05).Results: All specimens of IPS Emax press ceramic showed significant increase in CR after 300-hour accelerated aging time (P=0.005). Polished samples showed significantly higher opacity compared with that of the glazed ones (P=0.018).Conclusion: Within the limitations of this study, it may be concluded that the glazed specimens showed more stability in their translucency than the polished specimens.

Background and Aim: Diagnosis of dental caries with Diagnodent device has been found to be comparable to visual and radiographic diagnostic methods. The aim of this study was to determine the effect of aging, Staining, and Bleaching on Diagnodent readings in composite resin restorations.Materials and Methods: This was an experimental in vitro study in which 108 disk-shaped specimens were fabricated from 6 different composite resins including: 3 M p60, Kerr point 4, Vivadent Heliomolar, Ultradent flow, Tetric flow and Kerr flow. The samples were divided into 3 groups. Group 1was aged in water, group 2 was stained with tea and group 3 was bleached with 16% Carbamide peroxide. Specimen Fluorescence was measured with Diagnodent (Kavo- U.S) before and after these treatments. Data were analyzed using mixed repeated Measure Model ANOVA.Results: This study was performed on 108 composite resin specimens. All samples aged in water showed higher reading values; only Tetric flow exhibited a lower mean value (P<0.001). All samples stained with tea showed higher readings(P<0.001) and all materials bleached with 16% Carbamide peroxide were reported to have lower values; only Kerr flow exhibited a higher mean value than basic situation.Conclusion: The results indicate that aging and staining can result in an increase in the Diagnodent readings of the composite resin restorations while bleaching lead to a decreased the readings. However, the reported differences in Diagnodent readings were not significant enough to result in a false positive diagnosis of caries.

Background & aim: Esthetic attention of teeth is increasing, nowadays. After aging, restorative composite materials lead to discoloration and bleaching is one of the effective ways to eliminate of restorative composite discolorations. The aim of this study was to investigate discoloration after office bleaching with Hydrogen peroxide 40%.Materials and Methods: in this experimental in vitro study, From each composite (Z100, Z250, Z350, P90) A total of 24 composite discs were prepared with dimensions of 3 * 8. aging and staining process is done for samples in 4 weeks, then spent the 5000 cycle in Thermocycling devices. The samples are numbered and base line color of each composite is record. Samples were divided into two subgroups with 12 member, and each subgroup exposed to different treatment: 1- untreated control group 2- hydrogen peroxide 40% (Office B.). After 14 days of treatment Composite recorded secondary colors and color changes were calculated. The data were analyzed by ANOVA and Tukey and a significance level of 0.05 was determined.Results: Discoloration after bleaching in composite Z100, Z250, Z350 and P90 were (16.04±2.68), (21.13±3.43), (16.61±2.26) and (7.53±2.36), respectively which had significant difference with control group. (p<0.05). Discoloration of Z250 had significant difference compare with others. (p<0.001)Conclusion: office bleaching causes significant color change in the all types of stained composites and The greatest effect was on the Z250.

Introduction: Discoloration is one of the most common reasons for replacement of resin composites. The purpose of this study was to compare the color stability of three Methacrylate-based Resin Composites (Filtek Z250, Filtek Z250x, Filtek Z350xt) with Silorane-based Resin Composites (Filtek P90) after Accelerated Artificial aging (AAA).Materials & Methods: In this in vitro study 56 composite discs were prepared (N=14). CIE L*a*b* parameters of each specimen were measured by a reflectance spectrophotometer after 24h and 384 h of AAA. Then Color change (DE) of each composite was calculated. Data were analyzed by one way ANOVA, Tukey and paired t-test at the significance level of 0.05.Results: DE values of Filtek Z250, Filtek Z250x, Filtek Z350xt and Filtek P90 were 7.77, 5.86, 8.95 and 8, respectively. One way ANOVA demonstrated a significant difference between DE values of composites (P˂0.001). Tukey’s test revealed that DE value of Filtek Z250xt was significantly lower than those of other composites (P˂0.05).Conclusion: Silorane and methacrylate based composites showed a color change more than the clinically acceptable level (DE˃3.3) after AAA. Filtek Z250xt showed the lowest color change and other composites showed relatively similar color change.

Background and Aim: One of the most noticeable problems of composite restorations is color change of them over the time Due to this the most important advantage of composites which is providing esthetic is gone, so restorations need to be changed. The purpose of this study is to evaluate the effect of aging on color stability of two types of Bleached shade composites. Materials and methods: In this in vitro study 10 disk shape samples of each two nanohybride composit es DBl XL( IPS Empress Direct, Ivoclar Vivadent, Schaan, Liechtenstein) and Ebl L( IPS Empress Direct, Ivoclar Vivadent, Schaan, Liechtenstein in same size werefabricated. The primary color assessment was done by spectrophotometer matched which CIEI*a*b. Samples were done by the 10000 cycles of aging process which was equal to 1 clinical year. and then had the final test with her spectrometer. The results were evaluated with one way Anova. Results: the color change wasn’ t perceptible( p=0. 136), while the difference in a* parameter between composites was perceptible and DBI was more than EBI. ( p=0. 000) The differences of b and Δ E parametres were not significant for two evaluated composites (p=0. 377 and 0. 136, respectively) Conclusion: . The color change of bleached shade enamel and dentin resin composites after aging was acceptable clinically. (Δ E≥ 3/3).