Abstract
Effect of salivary contamination on shear bond strength of three different dentin adhesive systems
Dr. H. Kermanshah* - Dr. H. Haj miragha** - Dr. SH. Gatoeizadeh***
*- Assistant Professor of Operative Dentistry Dept. - Faculty of Dentistry – Tehran University / Medical Sciences.
**- Assistant Professor of Fixed Prosthodontics Dept. & Dental Research Center - Faculty of Dentistry – Tehran University / Medical Sciences.
 ***- Dentist.
Background and Aim: Salivary contamination during application of bonding agents may adversely affect adhesive/dentin bond strength. This investigation evaluated the effect of salivary contamination on the shear bond strength of three different bonding systems without treatment.
Materials and Methods: Seventy-two intact posterior extracted human teeth were used in this interventional in vitro study. The tested materials consisted of ScotchBond MP (SBMP), SingleBond (SB) and Prompt which are considered as three-step, fourth generation two-step, fifth generation and one-step, sixth generation bonding agents, respectively. For each tooth, the enamel on the buccal surface was removed by a diamond disc. Specimens were assigned to 12 groups according to the studied adhesives: SBMP into 5, SB into 4 and Prompt into 3 groups. Dentin surfaces were contaminated with natural saliva for 5 seconds. Cylinders of composite were applied onto the dentin surfaces using plastic cylindrical molds. The shear bond strength of the specimens was determined with an Instron testing-machine at a crosshead speed of 0.5 mm/min. The results were analyzed by one-way ANOVA and Tukey HSD tests.
Results: A significant difference was not observed between the contaminated SBMP and SB groups, but the difference between the contaminated and uncontaminated specimens was significant. In the Prompt groups, the difference between the contaminated and uncontaminated samples was not significant. No significant difference was found between the shear bond strengths of the adhesives, except for Prompt and SBMP.
 Conclusion: Shear bond strength depends on the type and structure of the applied adhesive and the stage at which salivary contamination occurs.
 Key words: Dentin bonding - Shear bond strength - Composite resin - Saliva contamination