Efficacy of nine commercial one step dentin adhesives

Objectives: To simplify the clinical handling of the dentin bonding procedures, one step dentin adhesives have been developed though the efficacy of these systems has not been consistently clarified. The aim of this study was to investigate the effect of nine commercial one step bonding system by measuring the contraction gap width of the resin composite in a dentin cavity. Materials and methods: Nine commercial one step bonding systems, (Absolute, Absolute 2, Bond Force, Fluoro Bond Shake One, G-Bond, i-Bond, One-up Bond F plus, Prompt L-pop and S3 bond) were used. A cylindrical cavity, 3 mm in diameter and 1.5 mm deep, was prepared in the dentin of extracted human tooth. The one step adhesives were applied in the cavity according to the manufacturers' instructions and a commercial resin composite (Palfique Estelite, Tokuyama, Japan) was filled. Ten minutes after the irradiation of composite, the marginal adaptation of resin composite was inspected under a light microscope and possible contraction gap width was measured. Ten specimens were prepared for each system and the gap value was statistically analyzed by Fisher's PSLD (p<0.05). For the positive control, the dentin cavity was conditioned with 0.5 mol EDTA and primed with 35% glyceryl mono-methacrylate solution. Then a commercial dentin bonding agent (Clearfil Photo Bond, Kuraray, Japan) was applied prior to the resin composite filling. Results: Complete marginal adaptation of composite was observed only in the control group. The gap values of tested dentin bonding systems were statically classified into two groups. Three one step bonding systems (Prompt L-pop, Absolute and Fluoro Bond Shake One) exhibited significantly inferior marginal adaptation compared to that of other seven groups. Conclusion: The efficacy of commercial step less dentin bonding systems tested in this study was incomplete and required some improvement because the contraction gap formation was not prevented completely.