Composite cure and pulp-cell cytotoxicity associated with LED curing lights.

Area of Science:

• Dental Materials Science
• Biocompatibility Testing
• Polymerization Technology

Background:

• Dental composites are widely used restorative materials.
• Light curing units (LCUs) are essential for composite polymerization.
• Evaluating the biocompatibility of polymerized composites is crucial for clinical success.

Purpose of the Study:

• To compare the polymerization depth (cure) and pulp-cell cytotoxicity of a mini-filled resin composite when polymerized by different light-emitting diode (LED) and halogen-based light curing units.
• To investigate the relationship between composite cure and pulp-cell cytotoxicity.
• To assess the differential responses of pulp fibroblasts and odontoblasts to leached composite components.

Main Methods:

• Resin composite specimens were polymerized using two LED (E-light, Freelight) and two halogen (Max, Astralis 10) light curing units.
• Polymerization cure was quantified by measuring top and bottom surface hardness (KHN).
• Pulp-cell cytotoxicity was assessed using a direct contact method with rat incisor tooth slices, followed by histomorphometric counting of fibroblasts and odontoblasts.

Main Results:

• High-intensity halogen (Astralis 10) showed significantly greater top surface cure than other lights. Conventional halogen (Max) and LED (Freelight) showed better bottom surface cure than E-light LED.
• Specimens cured with conventional halogen (Max) exhibited the lowest cytotoxicity.
• LED curing lights showed device-dependent differences in both cure and cytotoxicity; cure was not correlated with cytotoxicity.

Conclusions:

• The degree of composite cure and resulting pulp-cell cytotoxicity are influenced by the specific LED or halogen curing device employed.
• Composite cure depth does not predict pulp-cell cytotoxicity.
• Pulpal fibroblasts and odontoblasts exhibit distinct responses to unreacted or leached components from dental composites.