Effects of Smeared Layer on Luting Strength of Dental Cements.

Effects of smeared layer on the bond strength between dentin and dental cements were evaluated. Four surface conditions (No treatment, K-etchant, Dentin conditioner and EDTA) were prepared on the ground dentin of bovine frontal teeth. A copper tube was fixed and filled with a dental cement (zinc-phosphate cement or glass-polyalkenoate cement). A hook was embedded in the tube, with or without 1 MPa load during cementation. The bond strength was measured by a tensile test using a universal testing machine. No treatment had the largest bond strength of zinc-phosphate cement with or without load. No treatment, Dentin conditioner and EDTA had large bond strengths of glass-polyalkenoate cement with or without load; the bond strength of K-etchant was small without load and comparable to those of other surface conditions when load was applied. These results suggested that the bond strength of three surface conditions was not stronger than that of no treatment. Therefore, the elimination of smeared layer was concluded to have no advantage for increasing the bond strength between dentin and dental cements.