الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
The present study was conducted to evaluate the surface roughness, Ra and color stability, ΔE of a dimer acid-based composite (N’Durance, Septodont), Urethane dimethacrylate-based composite (Venus diamond, Heraeus Kulzer) and Bisphenol A diglycidil dimethacrylate-based composite (harmonize, Kerr). Four different polishing systems were used Jiffy natural universal wheels (Ultradent), Sof-Lex spiral wheels (3M ESPE), HiLuster (Kerr) and Enhance system (Dentsply).
A total of 72-disc specimens were prepared with 8mm in diameter and 4mm in thickness. Twenty-four disc specimens were prepared for each type of resin composites tested (n=24)
The samples of the composites were divided according to the type of resin-based composite used into three equal groups (n=24 for each group) and each group was further subdivided into 4 subgroups (n=6 for each subgroup) according to the four polishing systems used in this study.
Atomic force microscope, AFM (SPM-9700, SHIMADZU) was used to measure surface roughness. Color change (ΔE) for each specimen was measured using a digital spectrophotometer (VITA Easyshade Compact). After baseline color measurements, all of the specimens were kept in staining coffee solution for 2 days at 37˚C in an incubator then the readings were taken and ΔE was calcaulated.
Comparing the composite resin materials according to Ra (for all four polishing systems) ranked from lowest to highest surface roughness, the order was: N’Durance (mean=37.07 ± 9.12nm) < Harmonize (mean=43.55 ± 18.33nm) < Venus diamond (mean=82.29 ± 51.67nm). Dunn-Sidek test showed that Venus diamond had significantly the highest Ra values among the composite resins (p < 0.05). Although N’Durance showed the lowest Ra values, no significant differences were found among this composite and Harmonize (p > 0.05).
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The order of polishing systems (for all three composite resins), ranked from lowest to highest surface roughness, was as follows: Jiffy natural universal (mean=28.70 ± 7.97nm) < Enhance (mean=40.87 ± 10.19nm) < Sof-Lex wheels (mean=69.07 ± 25.46nm) < Hiluster (mean=78.59 ± 57.55nm). The smoothest surface was obtained with the use of the complete sequence of Jiffy natural universal after finishing tungsten carbide bur in all composite resin groups except for N’Durance composite which was best polished with Enhance polishing system.
Comparing ΔE values after 2 days in total sample (n=72), the highest ΔE values were obtained for Harmonize (mean=3.62 ± 0.79) (p < 0.05). N’Durance was found to be the most stain-resistant group (mean=2.73 ± 1.29) (p < 0.05). Venus diamond showed an intermediate discoloration between the other two composite groups (mean=2.87 ± 1.75) (p < 0.05).Moreover, Enhance cups and polishing pastes after finishing carbide burs showed the least ΔE values for the whole different composite types (mean=2.43 ± 1.45) with no significant difference between Enhance, Jiffy natural universal and Hiluster polishing systems (p > 0.05).