Table 2.

Components of the materials used in this study.

Material	Composition
Filtek™ Z350 XT	Bis-GMA, UDMA, TEGDMA, Bis-EMA and fillers 78.5% by weight (63.3% by volume): a combination of non-agglomerated/non-aggregated 20 nm silica filler, non-agglomerated/non-aggregated 4 to 11 nm zirconia filler, and aggregated zirconia/silica cluster filler (comprised of 20 nm silica and 4 to 11 nm zirconia particles)
Filtek™ Supreme Ultra Flowable Restorative	BisGMA, TEGDMA, Procrylat resins and fillers 65% by weight (46% by volume): a combination of ytterbium trifluoride filler 0.1 to 5.0 μm, a non-agglomerated/non-aggregated surface-modified 20 nm silica filler, a non-agglomerated/ non-aggregated surface modified 75 nm silica filler, and a surface-modified aggregated zirconia/silica cluster filler 0.6 to 10 μm (comprised of 20 nm silica and 4 to 11 nm zirconia particles)
Filtek™ One Bulk Fill Restorative	AUDMA, UDMA and 1, 12-dodecane-DMA, and fillers 76.5% by weight (58.4% by volume): a combination of a non-agglomerated/non-aggregated 20 nm silica filler, a non-agglomerated/ non-aggregated 4 to 11 nm zirconia filler, an aggregated zirconia/silica cluster filler (comprised of 20 nm silica and 4 to 11 nm zirconia particles) and agglomerate 100 nm particles ytterbium trifluoride filler
Ketac™ Universal Aplicap™ Glass Ionomer Restorative	Powder: Oxide glass > 95% by weight Liquid: Water, copolymer of acrylic acid-maleic acid, tartaric acid and benzoic acid
Celtra Duo® ceramic block	Silicon dioxide (58% by weight), phosphorus pentoxide (5% by weight), alumina (1.9% by weight), lithium oxide (18.5% by weight), zirconium dioxide (10.1% by weight), terbium oxide (1% by weight), ceria (2% by weight) and zirconium dioxide diluted completely in glass matrix (10% by weight)
Porcelain Etch®	4.9% hydrofluoric acid
Silane	3-methacryloxypropyltrimethoxysilane, ethanol
Single Bond Universal Adhesive	10-MDP Phosphate Monomer, HEMA, dimethacrylate resin, Vitrebond™ Copolymer, filler, ethanol, water, initiators, silane