Fatigue of Composite Using Phosphoric Acid and Two Self-Etching Systems

*3138 Fatigue of Composite Using Phosphoric Acid and Two Self-Etching Systems*
L.D. DILLON¹, R.S. WILLIAMSON², and L.D. ZARDIACKAS¹, ¹University of Mississippi, Jackson, USA, ²University of Mississippi, Jackson Objectives: The adhesive strengths of self-etching systems that bond composites to enamel have not been clearly defined. This current study investigates the adhesive strengths of Clearfil SE and 3M's experimental self-etching system. The study also evaluates the adhesive strengths at etching times of 5, 15, and 30 seconds. Methods: Bovine incisors were embedded in epoxy and prepared using the manufacturers instructions. Samples were then mechanically tested. Single cycle shear strengths of each material were evaluated at .1mm/sec and shear fatigue properties were evaluated at 5Hz to 100,000 cycles or failure. Results: Results of the single cycle tests showed significant differences between the 5 and 15-second groups and the 5 and 30-second groups. The peak load and stress of the 5-second groups was significantly less (p<.05). Fatigue testing of the 15-second group had the maximum stress to failure at 100,000 cycles. The second part of the study evaluated 2 different self-etching systems in single cycle shear and fatigue. Results of the single cycle testing showed no significant differences as a function of materials. Fatigue results showed the Clearfil SE to have the maximum stress to failure at 100,000 cycles. Scanning Electron Microscopy was performed on all groups. Conclusion: These results show that shear bond testing is not a good predictor of fatigue behavior. Shear bond testing showed no difference between the 15 and 30-second groups; however, a difference did exist between the 15 and 30-second groups in fatigue with the 15-second group having the greatest fatigue strength. Likewise, no difference is seen when performing shear bond testing between the two self-etching systems, but a significant difference between the two systems is seen when performing fatigue testing. Supported by 3m Dental, St. Paul, MN and the University of Mississippi School of Dentistry.
Seq #335 - Adhesion III 10:15 AM-11:30 AM, Saturday, 13 March 2004 Hawaii Convention Center Exhibit Hall 1-2
Back to the Dental Materials: I - Adhesion-Composite Bond Strength Program Back to the IADR/AADR/CADR 82nd General Session (March 10-13, 2004)
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