الفهرس 
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Abstract
1) This research was performed to evaluate and compare the influence of various polishing methods on the surface and interfacial roughness of supra-nanofilled, nanohybrid and nanofilled resin composites after thermocycling.
2) Ninety prepared samples were equally divided into three main groups (C1, C2 and C3) based on the kind of resin composite utilized in present research (n=30); (C1: Omnichroma, C2: Harmonize and C3: Filtek Z350XT) resin composites. Every group was subdivided into three subgroups (P0, P1 and P2) according to the type of polishing system utilized (n=10); (P0: without polishing, which served as control group, P1: PoGo micro-polisher discs, and P2: Sof-Lex spiral polishing system).
3) Class-V cavities were prepared on labial surfaces of extracted human maxillary second premolars with No. 330 carbide bur using a high-speed handpiece under copious amounts of air-water spray coolant.
4) After etching and bonding procedures, the restorative materials were packed into prepared cavities then photopolymerized following to the manufacturers’ instructions through transparent polyester strip, the cured specimens were either left without polishing or polished either with PoGo micro-polisher discs, or Sof-Lex spiral polishing systems according to their subgrouping.
5) As per the guidelines provided by the manufacturer, the polymerized resin composite samples were polished with flat broad surface of the PoGo disc at 15,000 rpm for 30 Seconds with a slow-speed micro-motor handpiece while other specimens were contoured with medium grit disc (orange) at medium speed of 15,000rpm for 15 Seconds without water spray then polished with fine (beige) and ultra fine (pink) spiral wheels by using linear movements at medium speed of 15,000 rpm for 15 Seconds using a slow-speed micro-motor handpiece.
6) Thermocycling test was fabricated in order to simulate the daily fluctuations in the temperature of the oral cavity. Thermocycling of 10,000 cycles between 5°C and 55°C with a dwell time of 30 Seconds are necessary to simulate one year of in-vivo clinical service.
7) Profilometer was utilized to measure the surface and interfacial roughness of the resin composite prior and following the thermocycling. The collected data was tabulated and statistically analyzed.
Results:
1. Influence of composite kind regardless of polishing method, thermocycling and region:
Harmonize Universal displayed the statistically significantly greatest mean Ra followed by Filtek Z350 XT while Omnichroma displayed the statistically significantly least mean Ra.
2. Influence of polishing method regardless of polishing method, thermocycling and region:
Polyester strip displayed the statistically significantly greatest mean Ra. Sof-Lex displayed statistically significantly lesser mean value. PoGo discs displayed the statistically significantly least mean Ra.
3. Influence of thermocycling regardless of composite kind, polishing method and region:
There was a statistically significant increase in mean Ra after thermocycling.
4. Influence of region regardless of composite type, polishing system and thermocycling:
Composite surface displayed statistically significantly lesser mean Ra than at the enamel composite restoration interface.
5. Influence of different interactions of variables on Ra:
Using PoGo after thermocycling whether at composite surface or interface regions; Harmonize Universal displayed the statistically significantly greatest mean Ra. Filtek Z350 XT displayed statistically significantly lesser mean value. Omnichroma displayed the statistically significantly least mean Ra.
Whether with Omnichroma, Harmonize Universal or Filtek ZX350-XT before thermocycling at resin composite surface; Sof-Lex displayed the statistically significantly greatest mean Ra. PoGo displayed statistically significantly lesser mean value. Polyester strips displayed the statistically significantly least mean Ra.
After thermocycling whether at resin composite surface or interface regions; polyester strips displayed the statistically significantly greatest mean Ra. Sof-Lex displayed statistically significantly lesser mean value. PoGo displayed the statistically significantly least mean Ra.