Abstract: Abstracts: Objective To evaluate dentin bond strength and nanoleakage of 2single bottle universal adhesives used in selfetch modes.Methods 40 flat dentin surfaces were prepared.Composite resin was lutinged on the dentin surface using 2 different adhesives （Singlebond Universal,AllBond Universal）in selfetch mode.Half bonding specimens were stored in water for 24 h （not aging）,and half were subjected to 10,000 times thermocycling （aging）.Then all the specimens were sectioned into composite/dentin beams to submit to microtensile bond strength （μTBS）testing.Data were statistically analyzed by Oneway ANOVA and Tukeys test （α=0.01）.Respective adhesive interfaces and nanoleakage were evaluated by SEM.Results Both groups showed a μTBS more than 30 MPa.No significant difference existed between the 2 adhesives.10,000 times thermocycling decreased μTBS of both adhesives.SEM showed nanoleakage in both groups.Conclusions The 2 adhesives provide high bond strength to dentin in selfetch mode.However,nanoleakage still exists.