Background:Although most of the studies investigated color stability of different restorative materials, evaluation of color stability of composites after immersion in multiple beverages in the same day by an in vitro oral simulation study is unclear.Objective:To assess color change of different restorative materials at the end of days 1, 14, and 30 of immersion in multiple liquid types to mimic the oral environment in vitro.Method:Ten disc-shaped specimens were made from each of four different resin composites (Filtek Z250, Voco x-tra base, Beautifil Flow Plus, Beautifil II). Baseline color value of each sample was measured using a spectrophotometer. Each composite was respectively immersed in coffee, an orange/pomegranate juice mixture, black tea, and a mouth rinse on the same day to mimic daily liquid consumption of individuals. Color measurements were taken after 1, 14, and 30 days by spectrophotometer and color change values were calculated. Statistical analyses were executed by one-way ANOVA/Tukey HSD and repeated-measures ANOVA.Results:All materials showed significant color change after 1, 14, and 30 days (P < 0.01) of immersion in liquids, with the lowest color alteration observed at the 1st day and the highest observed after the 30th day. Among the materials tested, at each time point (1, 14, and 30 days), the lowest color alteration was detected in Filtek Z250 and the highest color alteration was detected in Beautifil II.Conclusion:Color alteration of composite resins is affected by composite type and storage time. With the exception of 1 day of storage, color changes of all materials were substantial and clinically unacceptable.

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PurposeThe aim of this study was to evaluate the effect of a surface sealant on the surface roughness of different composites and compare their microhardness values. Materials and MethodsSixty disc-shaped specimens were prepared and assigned to 6 groups (n =10). Groups were prepared as follows; Group 1 (Herculite XRV Ultra), Group 2 (Beautifil Bulk Restorative) and Group 3 (Filtek Bulk Fill Posterior Restorative). Groups 4, 5, and 6 were prepared by applying a surface sealant (BisCover LV) on the specimens in groups 1, 2 and 3. Surface hardness of the discs in group 1, 2, and 3 and surface roughness of the discs in all groups were measured using the Vickers hardness test and a profilometer, respectively. One-way ANOVA was used to test for differences among the groups. ResultsNo significant differences were observed in the microhardness and roughness between the experimental and control groups for each restorative materials. Group 3 showed the highest surface hardness and group 4 showed the lowest surface roughness values. ConclusionUsing the BisCover LV resin after the polishing step has no significant effect on the surface roughness. The highest hardness values were obtained for the Filtek Bulk Fill Posterior Restorative after the polishing step. The smoothest surfaces were obtained for all experimental groups using the BisCover LV resin after the polishing step, Herculite XRV Ultra showed lower average roughness values than the other materials.

This study evaluated the adhesion of conventional and self-adhesive resin cements to indirect resin composite (IRC) using different surface conditioning methods. Cylindrical IRC specimens (N = 192) were randomly assigned to four surface conditioning methods (n = 8 per group): (a) Control group, (b) Hydrofluoric acid, (c) Tribochemical silica-coating, and (d) 50 m Al2O3 air-abrasion. Specimen surfaces were finished using silicon carbide papers up to 600 grit under water irrigation, rinsed and dried. Direct composite blocks were bonded to IRC specimens using three conventional resin cements (Multilink, Panavia F2.0, and Resicem) and three self-adhesive resin cements (RelyX U100, Gcem, Speed Cem). Specimens were subjected to shear bond strength test in a Universal Testing Machine (0.5 mm/min). Failure types were categorized as mixed, adhesive and cohesive. Data were analyzed using 2-way ANOVA and Tukey's tests. Two-parameter Weibull modulus, scale (m) and shape (0) were calculated. The bond strength results (MPa) were significantly affected by the surface conditioning method (p < 0.0001) and cement type (p < 0.001). For Panavia F2.0, Resicem, air-abrasion with 50 m Al2O3 significantly increased the results (22.6 ± 6.5, 26.2 ± 6.5, respectively) compared to other conditioning methods (13.6 ± 1.4-21.9 ± 3.1) but for Multilink, hydrofluoric acid etching (20.5 ± 3.5) showed significantly higher results (p < 0.01). For the self-adhesive resin cements, air-abrasion with 50 m Al2O3 significantly increased the results compared to other conditioning methods, except for RelyX U100 (p < 0.05). After air-abrasion with Al2O3, Gcem, (11.64), RelyX U100 (9.05), and SpeedCem (8.29) presented higher Weilbul moduli. Exclusively cohesive failure in the IRC was observed with RelyX U100 and Speedcem after Al2O3 airabrasion.

a faculty of dentistry, department of restorative dentistry, Medipol university, istanbul, Turkey; b faculty of dentistry, department of restorative dentistry, Kemerburgaz university, istanbul, Turkey; c faculty of dentistry, department of restorative dentistry, Trakya university, edirne, Turkey; d faculty of dentistry, department of restorative dentistry, university of istanbul, istanbul, Turkey