Table 1.

The compositions of the tested adhesives and composite resin

Materials	Compositions	Manufacturer	Manufacturer’s instructions
1-UAs	Clearfil Universal Bond Quick 2(UBQ2)	10-MDP, Bis-GMA, HEMA, hydrophilic amide monomers, urethane tetramethacrylate (UTMA), colloidal silica, sodium fluoride, CQ, ethanol, water	Kuraray Noritake Dental, Japan	1. Apply bond (Waiting time: 0 s)2. Dry with mild pressure air-blowing 3. Light-cure for 10 s
UBQ2-U(UTMA Free UBQ2)	Same compositions as UBQ2 but UTMA was removed.
UBQ2-F(Filler Free UBQ2)	Same compositions as UBQ2 but filler was removed.
Clearfil Universal Bond Quick ER(UBQ)	10-MDP, Bis-GMA, HEMA, hydrophilic amide monomer, colloidal silica, ethanol, dl-camphorquinone, accelerators, water, sodium fluoride
2-SEAs	Clearfil SE Bond 2(SE2)	Primer;10-MDP, HEMA, hydrophilic aliphatic dimethacrylate, CQ, water	1. Apply primer for 20s2. Dry with mild air-blowing3. Apply bond4. Distribute evenly with mild air-blowing 5. Light-cure for 10 s
Bond; 10-MDP, Bis-GMA, HEMA, hydrophobic aliphatic dimethacrylate, CQ, initiators, colloidal silica
Composite resin	Clearfil AP-X	Bis-GMA, TEGDMA, camphorquinone, photo initiators, pigments, silanated barium glass, silanated silica	Light cure for 40s