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Aims and objectives: To evaluate the effect of saliva contamination on the shear bond strength of one bottle (single bond) and self etch primer (Clearfil SE Bond) adhesive systems to dentin and to determine the effect of contaminant removing treatments on the recovery of shear bond strengths.

Materials and methods: Eighty human molars were embedded in rectangular aluminium moulds with self-curing acrylic resin. The occlusal dentin surface was exposed by wet grinding with No. 800 silicon carbide abrasive paper. The specimens were randomly divided into eight groups. Group 1 to Group 4 were treated with Single Bond (3M ESPE) and Group 5 to Group 8 were treated with Clearfill SE bond (Kuraray Co, Ltd, Osaka, Japan). For Single Bond, the grinding surface was treated with 32% phosphoric acid and divided into four groups: Group1 control (uncontaminated), Group 2 (salivary contamination, completely dried), Group 3 (salivary contamination, rinse and blot dried) and Group 4 (salivary contamination, re-etching for 10 seconds, rinse and blot dried). For SE bond, the following surface treatments were done: Group 5 control (uncontaminated), Group 6 (primer, salivary contamination, dried), Group 7 (primer, salivary contamination, wash and dried), Group 8 (after procedure of group 6, re-application of primer). Each bonding agent was applied and light cured for 10 seconds. The teeth were then positioned and stabilised in a stabilizing device which holds a Teflon block having a circular hole of 3mm diameter and 2 mm thickness. Hybrid composite resin Filtek Z-250 (3M ESPE) was condensed into Teflon mold (3x2 mm) and light cured for 20 seconds to form resin cylinders. All the specimens were stored in distilled water at 370c for 24 hours and shear bond strength testing was done in an Instron Universal Testing Machine (5500R) at a cross head speed of 0.5mm/min. The shear bond strength data for the two adhesives was subjected to 1-way ANOVA while comparison of means between groups was done by t-test.

Results: In the Single Bond groups, Group 2 showed statistically significant lower shear bond strength than Group 1 (control),3 and 4(p<0.05). In the clearfill SE groups, group 6 and group 7 showed lower shear bond strength than Group 5 (control)and group8(p<0.05).

Conclusion: When using Single Bond total etch adhesive and when the etched surface is contaminated by saliva, blotting the surface and applying the primer can recover the bond strength. Complete drying of the salivary contaminated surface should be avoided. In the Clearfil SE Bond groups, the re-priming treatment resulted in the recovery of shear bond strength.

Adhesion, Contamination, Total etch, Self etch, Shear bond strength