Cytotoxicity of composite materials polymerized with LED curing units

Area of Science:

• Dental Materials Science
• Biocompatibility Testing

Background:

• Inadequate polymerization of dental resin composites can lead to unreacted monomer release, causing cytotoxicity to pulp tissue.
• The curing light's intensity and duration significantly impact resin composite polymerization and restoration longevity.

Purpose of the Study:

• To evaluate the cytotoxicity differences of resin composites polymerized with various LED curing unit modes.
• To assess the impact of different curing intensities and durations on composite cytotoxicity and genotoxicity.

Main Methods:

• Two composite materials were polymerized using high intensity (HIP), soft-start (SOF), and low intensity (LOP) modes of an LED curing unit.
• Lymphocyte cultures were exposed to polymerized and unpolymerized composites.
• Cytotoxicity was assessed using trypan blue exclusion and acridine orange/ethidium bromide staining; DNA damage was evaluated via alkaline comet assay.

Main Results:

• Unpolymerized composites and those cured with the high intensity mode (HIP) exhibited significant cytotoxicity.
• Significant DNA damage was observed with unpolymerized composites.
• The low intensity mode (LOP) demonstrated the lowest genotoxicity, indicating less DNA damage.

Conclusions:

• Longer curing times with lower light intensity result in less cytotoxicity than shorter exposures with higher intensity.
• Optimizing LED curing parameters, specifically intensity and duration, is essential for minimizing adverse biological effects of dental composites.