The bond strength of adhesives to dentin have been shown to be affected by a number of different factors, including intrinsic properties of the prepared dentin, various types of contamination and the chemical composition of the adhesive agent. The present study investigates the microtensile bond strength (μTBS) of two different bonding systems at different dentinal areas of primary dentin after saliva contamination. Caries-free primary molars were randomly divided into four groups (n = 10) for μTBS. Prime and Bond NT (etch-and-rinse) and Clearfil Protect Bond (two step self-etch) adhesives were tested under the following conditions: (a) control, (b) contamination with saliva prior to adhesive application. Following adhesive and composite superstructure application μTBS was measured. Maximum load at failure (N) was recorded and converted to MPa. Statistical analysis was carried out using one-way ANOVA with Tukey?s test. No statistically significant difference was found between the μTBS of the contaminated and control groups in the central region of primary dentin for either adhesive system tested (p>0.05). However, saliva contamination resulted in significant reductions in bond strength in the peripheral region (p<0.05) for both adhesive systems tested. In the saliva contaminated groups, μTBS was higher in the central region than in the peripheral region. The etch and rinse adhesive performed better than the two-step self-etching adhesive under saliva contamination in both the peripheral and central regions of primary dentin. Results indicate that saliva contamination should be avoided when restoring primary teeth with proximal cavities using both Prime and Bond NT (etch and rinse) and Clearfil Protect Bond (two step self-etch) adhesives. However, confirmatory studies are needed before conclusive recommendations can be made for clinical practice.
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