Effect of EDTA conditioning on bond strength to bovine dentin promoted by four current adhesives

To investigate the effect of disodium dihydrogen ethylenediamine tetraacetate dihydrate (EDTA) conditioning prior to the application of adhesive systems on the bond strength of resin composite to dentin.

80 bovine teeth were ground with 600-grit SiC paper to obtain flat dentin surfaces. Half of the specimens were conditioned with 0.5 mol EDTA aqueous solution (pH 7.4) for 60 seconds, water-rinsed and air-dried, and the other half were used without any treatment. The specimens were randomly divided in four groups of 10 each. The dentin surfaces were treated with each of two "all-in-one" adhesive systems (One-up Bond F, OB; Reactmer Bond, RB), a self-etching priming system (Clearfil SE Bond, SE), and a total-etch one-bottle bonding system (Single Bond, SB). For SB, the adhesive was applied on EDTA-conditioned dentin without H3PO4 etching. Then a layer of resin composite was placed and light-cured for 40 seconds. The tensile bond strength was measured and the resin-dentin interface was observed using a scanning electron microscope.

The mean and standard deviation of tensile bond strength in MPa to ground dentin were 9.3+/-3.5/OB, 11.6+/-2.0/RB, 23.2+/-4.9/SE and 19.7+/-4.1/SB. Bond strengths to EDTA-conditioned dentin were 15.0+/-3.0/OB, 16.8+/-3.6/RB, 22.8+/-5.2/SE and 19.4+/-5.1/SB. Duncan's Multiple Range test revealed that the EDTA-conditioned dentin showed significantly higher tensile bond strength than the non-conditioned one for "all-in-one" adhesive systems (P < 0.05) but no significant difference was found for the self-etching priming and total-etch one-bottle bonding systems. At the resin-dentin interface, EDTA-conditioned specimens formed thicker hybrid layers than non-conditioned ones for all systems except for SB.