Table 1.

Physical characteristics of experimental materials.

Material	Filtek Z350	Esthet X	Admira
Manufacturer	3M ESPE	Dentsply	Voco, Germany
Type	Nanocomposite	Microhybrid	Ormocer based
Organic matrix	Combination of a non-agglomerated/non-aggregated, 20 nm nanosilica filler, and loosely bound agglomerated zirconia/silica nanocluster, consisting of agglomerates of primary zirconia/silica particles	Resin matrix (a urethane-modified Bis-GMA) is based on the matrix used in TPH Spectrum	3-dimensionally linked inorganic-organic copolymers (ormocers) and additive aliphatic and aromatic dimethacrylates
Filler type	Bis-GMA, UDMA, TEGDMA, and Bis-EMA resins	Barium alumino fluoroborosilicate glass (BAFG) and nanosized silicon dioxide particles	Ba-Al-B-silicate glass
Average particle size	0.6–1.4 microns	0.02 to 2.5 microns (with an average of from 0.6 to 0.8 microns)	0.04–1.2 μm
Filler volume %	78.5% by wt/59.5% by vol	60% by volume	56% by volume/78% by wt