Aim: The aim of this study was to investigate the effect of desensitizing agents on microleakage of composite resin restorations bonded by one step desensitized self etch adhesive. Materials and methods: Class V cavities (3 Â 4 Â 2 mm) were prepared on the buccal surfaces of 30 human molars, Teeth were classified into three groups according to the type of adhesive used (n ¼ 10). Group 1: Adper Single Bond2. Group 2: l-bond. Group 3: is a control group of composite resin restoration without bonding agent. All cavities were restored with Filtek Z250 composite resin, stored in distilled water at 37 C for 24 h and thermal cycled for 500 cycles. The root apices were sealed with utility wax, and all the surfaces, except for the restorations and 1 mm from the margins, were coated with two layers of nail varnish. The teeth were immersed in a 3% methylene blue dye solution for 24 h, and then rinsed in running water, blot-dried and sectioned longitudinally through the center of restorations from the facial to lingual surface. The sections were blindly assessed for microleakage of dye penetration by two independent evaluators using a stereomicroscope at 30Â magnification for both the occlusal and gingival margins. Data were collected and statistically analyzed.Results: A ManneWhitney test demonstrated the highest significantly dye penetration rate for group 3 versus tested groups comparing the occlusal and gingival scores for each group, Wilcoxon Rank test showed significant difference for all groups. Etch and rinse adper single bond2 adhesive record a lower significant scores of dye penetration than self etch adhesive I-bond at both enamel and dentin margins. Conclusion: All adhesive systems exhibited dye penetration at both occlusal and gingival margins. Etch and rinse system is still considered a gold standard adhesive. Adper single bond2 revealed significantly less leakage compared to I-Bond.

The aim was to investigate the effect of thermocycling on the microshear bond strength of one solvent free self etch adhesive system, Bond-1SF, and two solvent containing self-etch adhesives, Futurabond DC and Adper Easy One. Materials and methods: Sixty caries free third molars were used to prepare specimens of dentin surfaces. The adhesives were applied on dentin surfaces according to the manufacturer's instructions then Grandio-SO Composite resin was condensed through a polyethylene tube with a one mm internal diameter and height attached firmly to dentin surfaces and light cured. The bonded specimens were stored in distilled water at 37 C for 24 h before being tested. Half of the bonded specimens were tested for microshear bond strength without thermocycling and the other half were thermocycled in water baths held at 5 c and 55 c with a dwell time of 1 min each for 500 cycles prior to testing. The micro shears bond strength before and after thermocycling was calculated and statistically analyzed to show the interaction between different materials. Results: Without thermocycling, the bond strength of Futurabond DC and Adper Easy, were 22.524 MPa and 23.397 MPa respectively, while Bond-1 SF solvent free one step at lowered mean value 22.284 MPa and the difference was not statistically significant (p > 0.05). After thermocycling the bond strength of Futurabond DC and Adper Easy were 14.904 MPa, 22.713 MPa respectively, while Bond-1 SF solvent free one step self etch adhesive had 18.318 MPa and the differences were statistically significant (p > 0.05). Conclusion: Thermocycling had a negative effect on the bonding of self etching adhesive systems to dentin and solvent free adhesive system has non-significant lower bond strength in relation to solvent containing adhesive systems.

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