Methods: Sixty carious free primary molars were prepared for micro-tensile bond strength (MBS)test.Specimens were randomly divided into six groups of ten. Prime& Bond NT(total-etch), Clearfil Protect Bond(two step self etch) and I Bond(one step self etch) adhesives were tested under the following conditions: (a) non-contaminated conditions; (b) after contamination of the dentin surface with fresh whole saliva for 20 seconds and removal of excess saliva before adhesive application. Following adhesive application TPH,Clearfil AP-X or Charisma was applied and light cured . MBS were measured using an Instron Universal testing machine running at a crosshead speed of 1 mm/minute. After measuring bond strengths, specimens were prepared for SEM evaluation and identifed for failure type. The results of MBS were submitted to analysis of variance ANOVA.
Results: No statistically significant difference was found between contaminated and non-contaminated superficial central dentin in both groups.However in superficial periferal dentin groups: both Prime& Bond NT and Clearfil Protect Bond noncontaminated groups showed higher bond strength than their contaminated groups.There was no statistically significiant difference between the bond strength of I Bond contaminated and noncontaminated groups.Among superficial periferal dentin contaminated groups there was no statistically significant difference were found. Prime& Bond NT showed significiantly higher bond strength than both I Bond and Clearfil Protect Bond noncontaminated groups in superficial periferal dentin. Also superficial central dentin showed higher bond strength than superficial periferal dentin in both contaminated and non contaminated groups.
Conclusion: The results revealed that saliva contamination did not effect bond strenght in superficial central dentin. Superficial central dentin groups showed higher bond strength than periferal dentin in both noncontaminated and contaminated groups.