Flexural performance of flowable versus conventional light-cured composite resins in a long-term in vitro study.

Area of Science:

• Dental Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Composite resins are widely used in restorative dentistry.
• Flowable composite resins (FCRs) offer advantages in handling and placement.
• Understanding their mechanical properties is crucial for clinical performance.

Purpose of the Study:

• To compare the flexural strength, flexural modulus, modulus of resilience, and water sorption of FCRs with conventional composite resins (CCRs).
• To evaluate the effect of long-term water storage on these mechanical properties.

Main Methods:

• Four FCRs were tested against four CCRs and a control minifilled hybrid composite.
• Specimens were subjected to flexural testing immediately after curing and after water storage (1 month to 1 year at 37°C).
• Water sorption was assessed by weight measurements of 1-year specimens.

Main Results:

• Most FCRs demonstrated significantly higher flexural strength than their CCR counterparts.
• One-year water storage led to a ≥1.5-fold increase in flexural strength and flexural modulus for FCRs compared to immediate testing.
• FCRs generally exhibited higher moduli of resilience than CCRs.

Conclusions:

• Flowable and conventional composite resins, even of the same brand, possess distinct mechanical properties.
• Long-term water storage positively influences the mechanical performance of FCRs.
• FCRs present a promising alternative to CCRs, offering improved mechanical characteristics.