Objective: To compare the dentin shear bond strength of three self-etching bonding agents with that of a conventional total-etch bonding system.
Materials & Method: Extracted third molars (120) were fixed in 10% formalin and randomly divided into eight groups of 15 specimens each. The specimens were mounted in acrylic resin and the surface ground to expose superficial dentin. A standardized smear layer was created by polishing the surfaces with wet 600-grit silicon carbide paper. Each adhesive system was placed on the specimen surface according to the manufacturers' instructions. The specimen then was mounted onto a standardized jig and light cured. Composite stubs of 2.38 mm in diameter and 3 mm high were placed directly on top of the bonding agent using incremental layers of Z250, shade A1 composite.
Each sample was paired randomly for testing under two different conditions: thermocycled and non-thermocycled. In the non-thermocycled group, samples were incubated for 24 hours at 37°C while the thermocycled group was cycled 750 times in alternating baths of 5°C and 55°C with a 20 second dwell time in each bath.
The bonds were subsequently stressed to failure using a universal material testing machine operating at a crosshead speed of 1 mm/min. The mean de-bonding force was measured in Newtons (N) and converted to Megapascals (MPa) for statistical analysis. Analysis was performed using the Mann-Whitney U-Test. The sample surfaces were subsequently examined under a stereomicroscope to assess the percentage of cohesive and adhesive failure.
Results: Mean results were given (MPa) for the non-thermocycled and thermocycled samples. (Scotchbond= 38.3 ± 4.5 and 30.1 ± 4.9; G-Bond= 25.4 ± 3.1 and 19.6 ± 2.2; L-Pop=23.9 ± 2.9 and 20.3 ± 3.2; Brush & Bond= 30.0 ± 4.5 and 29.5 ± 2.5). In both the non-thermocycled and thermocycled groups, the control had statistically greater bond strengths than G-Bond, L-Pop, or Brush & Bond (p< 0.05).
Conclusions: The shear bond strength of the total-etch system (control) was statistically higher than that of the self-etch systems. However, under conditions of the present study, the self-etch bonding systems investigated were capable of providing adequate dentin bond strengths.
J. Todd Milledge
Master of Science (MS)
Year Degree Awarded
Date (Title Page)
Library of Congress/MESH Subject Headings
Dental Bonding; Dental Materials; Dental Etching; Composite Resins
Loma Linda University Libraries
This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.
Alcaide, Jeff G., "Shear Strengths of Three "One-Step" Self-Etching Dental Bonding Agents" (2006). Loma Linda University Electronic Theses, Dissertations & Projects. 1316.
Loma Linda University Electronic Theses and Dissertations
Loma Linda University. Del E. Webb Memorial Library. University Archives