Table 1 Resin composites and glass ionomer restorative material used in this study

Bulk-fill resin composite

Filtek One Bulk Fill Posterior

Restorative (3 M ESPE, St.Paul, MN, USA)

AUDMA (1–10% by Wt.),

UDMA (< 10% by Wt.),

DDDMA (1–10% by Wt.)

Silica, Zirconia,

Zirconia/Silica cluster, Ytterbium- trifluoride (YbF3). The total filler load is 76.5% by Wt (58.5% by volume)

Silica 0.02,

Zirconia 0.004–0.011, Zirconia/silica cluster

(comprised of 0.02 Silica and 0.004 to 0.011

Zirconia particles),

0.1 Ytterbium trifluoride (YbF3)

Nanohybrid resin composite

Premise (Kerr, Orange, CA, USA)

Bis-EMA,

UDMA,

TEGDMA*

Prepolymerized filler, Barium glass. The total filler load is 84% by Wt. (69% by volume)

Prepolymerized filler, Barium glass filler 0.4

Glass ionomer restorative material

Ketac Universal (3 M ESPE, St.Paul, MN, USA)

Water (40–60% by Wt.), Copolymer of acrylic acid–maleic acid (30–50% by Wt.), Tartaric acid (1–10% by Wt.)

Oxide glass (96–99% by Wt.)

No greater than approximately 2.8 µm in size