Evaluation of new methods for composite repair.

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Restorative Dentistry

Background:

• Composite resins are widely used in dental restorations.
• Ensuring the longevity and strength of repaired composites is crucial for clinical success.
• Various surface treatments exist for composite repair, each with potential benefits and drawbacks.

Purpose of the Study:

• To compare the effectiveness of air abrasion (sandblasting), hydrofluoric acid (HF) etching, and acidulated phosphate fluoride (APF) for composite repair.
• To evaluate how different composite compositions and particle sizes influence repair bond strength.
• To assess the performance of a phosphonate resin bonding agent in conjunction with these surface treatments.

Main Methods:

• Five distinct composite materials (three hybrid, one small-particle, one microfill) were utilized.
• Surface treatments included air abrasion, HF etching, and APF application.
• A phosphonate resin bonding agent was employed for all repair procedures.
• Repair bond strength was measured to evaluate treatment efficacy.

Main Results:

• Air abrasion generally resulted in the strongest repairs, reaching approximately 60% of the original cohesive strength.
• Hydrofluoric acid (HF) exhibited variable effects, either enhancing or diminishing repair strength depending on the composite type.
• Acidulated phosphate fluoride (APF) demonstrated the lowest interfacial bond strengths across most composites, with an exception for the microfill composite.

Conclusions:

• Air abrasion is a highly effective surface treatment for composite repair, providing significant bond strength.
• The choice of surface treatment for composite repair should consider the specific composite material being used.
• HF etching's effectiveness is material-dependent, while APF is generally less effective for composite repair except for microfill types.