Table 1. The materials used in the present study .

Materials	Type	Description & Composition
Filtek P90 (3M ESPE, St. Paul, USA)	Silorane-based microhybrid composite (Shade: A3)	Silorane resin, initiating system: Camphorquinone, Iodonium salt, Electron donor; Quartz filler, Yttrium Fluoride
Silorane adhesive system (3M ESPE, St. Paul, USA)	Two-step self-etch	Primer: Phosphorylated methacrylates, Viterbond copolymer, Bis-GMA, HEMA, Water, Ethanol, Silorane-treated silica filler; Bond: Hydrophobic dimethacrylate, Phosphorylated methacrylates, TEGDMA, Silorane-treated silica filler
Filtek Z250 (3M ESPE, St. Paul, USA)	Methacrylate-based microhybride composite (Shade: A3)	Bis-GMA, Bis-EMA, UDMA, TEGDMA, Zirconia, Silica
Clearfil SE Bond (Kuraray, Osaka, Japan)	Two-step self-etch	Primer: MDP, HEMA, water, ethanol, initiator, accelerators, dyes; Bond: MDP, HEMA, Bis-GMA, colloidal silica, initiator

Bis-EMA: bisphenol Aethoxylated dimethacrylate; Bis-GMA: bisphenol A glycol dimethacrylate; HEMA: 2-hydroxyethyl methacrylate; MDP: 10-methacryloyloxydecyl di-hydrogen phosphate; TEGDMA: triethylene glycol dimethacrylate; UDMA: urethane dimethacrylate.