Table 1 Characteristics of composite resins evaluated in this study

Everx posterior

Short fiber composite

GC Corp., Tokyo, Japan

Short E-glass fiber filler, barium glass, Bis-GMA, PMMA, TEGDMA

74.2wt%

53.6vol%

Hybrid filler fractions and E-glass fibers (1–2 mm length), Ba-B-Si glass filler (0.1–2.2 µm) [17]

Filtek BulkFill Posterior

Nano fill

3M ESPE, St. Paul, MN, USA

Non- agglomerated/non-aggregated 20 nm silica filler, non agglomerated/non-aggregated 4 to 11 nm zirconia filler, aggregated zirconia/silica cluster filler, ytterbium trifluoride filler consisting of agglomerate 100 nm particles, ERGP-DMA, diurethane-DMA, 1, 12-dodecane-DMA

76.5 wt%

58.4 vol%

Fillers are a combination of zirconia and silica having a particle size of 0.01–4.5 microns and ytterbium trifluoride filler having a particle size of 0.1 -5.0 microns [18]

SonicFill 2

Nanohybrid

Kerr corp. Orange, CA, USA

Poly(oxy-1,2-ethanediyl), α,α′-[(1 methylethylidene)di-4, 1-phenylene]bis[ω-[(2- methyl-1-oxo-2-propen-1-yl)oxy]-Not available. 2,2′-ethylenedioxydiethyl dimethacrylate

81.3% wt % unreported

Nanoscale zirconium oxide, silica oxide particles (10–30 nm) [19]

X-tra fil

Hybrid

VOCO Cuxhaven, Germany

Barium- boron- alumino- silicate glass, Bis-GMA, UDMA, TEGDMA

86 wt%

70.1 vol%

0.04–3 µm [20]

Filtek Z250 Universal

Microhybrid

3 M ESPE, St. Paul, MN, USA

Zirconia/silica without silane treatment,

Bis-GMA, UDMA, Bis-EMA, TEGDMA

82 wt%

60 vol%

0.01 to 3.5 µm with an average particle size of 0.6 µm