Failure Strengths of Composite Additions and Repairs

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Restorative Dentistry

Background:

• Achieving equivalent failure strength in repaired composite restorations is critical for longevity.
• Surface treatments significantly influence the bond strength and mechanical integrity of repaired composites.
• Evaluating novel adhesives for composite repair is essential for clinical success.

Purpose of the Study:

• To assess the failure strengths of repaired composite restorations using various surface treatments.
• To compare the effectiveness of different chemical and mechanical surface preparations.
• To determine if new adhesive systems can restore the original failure strength of composite restorations.

Main Methods:

• Failure strength was measured using a four-point bending test on composite beams.
• Specimens included fresh and aged composites repaired with various surface treatments (roughening, acid etching, silane, adhesives, tribochemistry).
• Monolithic composite specimens served as controls, with statistical analysis using ANOVA and Fisher's PLSD.

Main Results:

• Repairing unground, freshly cured composites with a new multimode adhesive yielded strengths comparable to monolithic controls.
• Aged composites repaired with the new multimode adhesive (with or without tribochemistry) also showed no significant strength reduction.
• Grinding fresh composite surfaces or using conventional adhesives/other treatments on aged composites significantly decreased failure strength.

Conclusions:

• A new multimode adhesive effectively restores the failure strength of repaired composite restorations, matching original monolithic material.
• This adhesive system demonstrates efficacy on both fresh and aged composite substrates.
• Surface preparation methods significantly impact the mechanical outcome of composite repairs.