Table 1.

Composition of the resin composite used in this study.

Name of the Composite	Type of Composite	Manufacturer/Lot No.	Composition
HNT/TCN-0%	Experimental resin-composite	-----	Organic matrix: Bis-GMA, TEGDMA.
			Filler type: Silica micro-hybrid filler 80 wt.%
			Filler content: 80 wt.%
HNT/TCN	Experimental resin-composite	-----	Organic matrix: Bis-GMA, TEGDMA.
			Filler type: Silica micro-hydrid filler 72 wt.% and halloysite nanotubes 8 wt.%.
			Filler content: 80 wt.%
Filtek Z-350XT (Shade A1D)	Commercial nano-filled composite	3M ESPE (St Paul, MN, USA)/N702257	Organic matrix: Bis-GMA, Bis-EMA, UDMA, TEGDMA
			Filler type: Silica and zirconia nanofillers, agglomerated zirconia-silica nanoclusters
			Filler content: 82 wt.%