Aims and Objectives:To evaluate the effect of saliva contamination on the shear bond strength of a new two-step self-etch adhesive (P90 system adhesive) to dentin and to determine the effect of contaminant removing treatments on the recovery of bond strengths.Materials and Methods:The buccal surfaces of 40 human premolars were ground to expose dentin. The specimens were randomly divided into four groups. Group 1 is uncontaminated and serves as the control group. Further groups were divided based on the step in the bonding sequence when the contamination had occurred as follows: Group 2 (primer, saliva contamination, rinse and dry), group 3 (after procedure of group 2, reapplication of primer), and group 4 (after procedure like in control group, saliva contamination, rinse and dry). Filtek P90 composite resin cylinders of 3 mm diameter and 3 mm length were fabricated on the surfaces. Shear bond strength testing was done in an Instron Universal Testing Machine and the data were subjected to one-way analysis of variance (ANOVA) and Student's t-test.Results:With P90 system adhesive, group 2 and group 4 showed lower shear bond strength than group 1 (control) and group 3 (P < 0.05).Conclusion:Saliva contamination significantly decreased the shear bond strength of the adhesive to dentin.

Cervitec varnish was found to be effective in reducing S. mutans count for a 3-month period, when compared to Duraphat varnish.

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