Objective To compare the occluding effect of conventional penetrating resin,Single Bond desensitizer,and penetrating resin combined with ethanol wet-bonding on dentin tubules.Methods Sixty isolated premolar teeth were prepared to form dentin discs.The 60 teeth were divided into 3 groups based on a random number table:Group A,conventional penetrating resin;Group B,Single Bond desensitizer,and Group C,penetrating resin combined with ethanol wet-bonding.Each group comprised 20 teeth.Dentin discs were split in half along the longitudinal axis.Half of the disc served as the control;the other half was coated with desensitizer.Microscopic characteristics of the dentin surface and profile were determined by using a field emission scanning electron microscope.Results In group A,70.10％±2.13％ of the dentin tubule openings were covered by the resin.The penetration depth was 50±10.59 μm,and the resin was short and discontinuous.In group B,86.35％±1.73％ of the dentin tubules openings were covered.The penetration depth was 69± 11.98 μm,and the resin was sparse.In group C,95.65％± 1.46％ of dentin tubules openings were covered.The penetration depth was 177±9.17 μm,and the resin was compact and filled.Conclusion Penetrating resin combined with ethanol wet-bonding occludes dentin tubules better than conventional penetrating resin and Single Bond desensitizer.