Evaluation of monomer elution from two dentin bonding agents cured with halogen and LED lights

Polymerization of resin-based dental materials is not complete; and the release of unreacted monomers has undesirable effects on biocompatibility and integrity of material. The aim of this study was to evaluate the type and effect of dentin bonding agents, type of light curing unit, the distance between the tip of curing unit and surface of bonding agents on monomer leaching. This experimental study used 40 sound extracted teeth, with prepared cavities about 3x3x2 and 3x3x4 mm on the smooth surfaces. A self-etch bonding (Clearfil SE Bond Curary, Japan) and one etch and rinse (Scotch Bond multipurpose, USA) were applied on cavities according to the manufacturer’s instruction. The bonding agents were cured with halogen (Optilux 501, Colten) and LED (Ultalume 2, Vivadent) lights. The samples were saved in pure methanol with 37 ° C for 24h. Liquids were studied with gas chromatography (GC) for detection of different monomers. Data were analyzed using 3-Way ANOVA and Independent T-tests. The type of bonding agent had significant effect on monomer release. Scotch Bond released more monomer than Clearfil SE Bond (P=0.001). The effect of light curing unit on monomer leaching was not significant, but the samples of Scotch Bond with more distance released more monomer. Only HEMA monomer was detected from dentin bonding agents in this study. Scotch Bond released more HEMA than Clearfil SE Bond. Halogen and LED lights had no significant effect on monomer leaching. More distance between the tips of light causes less degree of polymerization.