Shear Bond Strength of Repaired Composites Using Surface Treatments and Repair Materials: An In vitro Study

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Restorative Dentistry

Background:

• Improving bond strength in composite repairs requires surface roughening for mechanical interlocking and bonding agents for wetting.
• Existing methods often involve increased surface roughness and bonding agents to enhance adhesion between new and old composite materials.

Purpose of the Study:

• To evaluate and compare the effects of different surface treatments and repair materials on the shear bond strength (SBS) of composite repairs.
• To assess the mode of failure (cohesive or adhesive) in repaired composite specimens.

Main Methods:

• Sixty aged composite specimens underwent various surface treatments: no treatment, diamond bur abrasion, or air abrasion (50 µ aluminum oxide).
• Specimens were repaired with fresh composite using Clearfil™ repair or All-Bond Universal adhesive systems.
• Shear bond strength (SBS) was tested after water storage and thermocycling; failure modes were examined microscopically.

Main Results:

• Air abrasion followed by Clearfil™ repair adhesive yielded the highest repair bond strength (32.3 ± 2.2 MPa).
• This combination demonstrated superior performance compared to other surface treatments and adhesive systems.

Conclusions:

• Surface treatment with air abrasion combined with Clearfil™ repair adhesive is a clinically viable option for repairing composite restorations.
• This approach effectively enhances the bond strength and durability of repaired composite materials.