Shear Bond Strength of Repaired Composite Using Single Bond Adhesive

Ayah Abdulla Al-Asmar, Alaa Sabra, Faleh Sawair, Ameen Khraisat


Objectives: The aim of this study was to evaluate the shear bond strength of repaired composite resin
restorations using one-step Single Bond Universal adhesive.
Materials and Methods: Sixty cylindrical composite samples (8 x 9 mm each) were prepared from
Filtek Z350 XT, light-cured and stored for 6 weeks. The surface of each sample was bur-roughened and
acid-etched with 37% phosphoric acid. Samples (N = 60) were randomly assigned into 2 groups. For
group 1 (the control group), silane coupling agent and bonding agent were applied in two separate steps.
For group 2 (the test group), Single Bond Universal adhesive containing both silane and bonding agents
was applied to the surface of the samples. Fresh composite resin was bonded to treated surfaces, and
samples were cured and stored for another 6 weeks. The shear bond strength (SBS) was measured and
analyzed using an independent samples t-test and descriptive statistics. Stereomicroscope examination
of the samples was done to assess the mode of failure between the original and the repaired composite
layers for the control and test groups.
Results: The mean initial failure SBS for the test group was significantly higher than that of the control
group (p < 0.001). Of the control group samples, 80% failed adhesively, while 100% of the test group
samples showed cohesive failure and a mixed mode of failure when observed under the
Conclusion: Single Bond Universal adhesive provides more reliable bond strength for repaired
composite resin restorations compared with two-step silane and bonding agent application.


Composite, Repair, Silane, Shear, Single bond universal adhesive.

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