Curing efficiency of three different curing lights at different distances for a hybrid composite

Area of Science:

• Dental Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Light curing is crucial for resin composite polymerization.
• Curing distance and light source characteristics influence material properties.
• Understanding these factors is essential for optimal clinical performance.

Purpose of the Study:

• To assess the impact of varying curing distances and three distinct light sources on resin composite surface microhardness.
• To investigate the relationship between power density and microhardness at different distances.

Main Methods:

• Ninety resin composite specimens were polymerized using three light curing units with different power densities.
• Curing was performed at distances ranging from 0 mm to 15 mm.
• Knoop hardness (KHN) was measured on top and bottom surfaces before and after 24-hour water storage; statistical analysis included ANOVA and regression.

Main Results:

• The Mini LED AutoFocus light yielded significantly higher KHN values than LEDemetron I and Optilux 401.
• Microhardness decreased linearly with increased curing tip distance.
• Effective hardness (>80%) was achieved in limited groups initially but improved after 24-hour water storage for most groups.

Conclusions:

• The light curing unit type and distance significantly affect resin composite microhardness.
• Mini LED AutoFocus demonstrated superior performance in achieving microhardness.
• Optimizing curing distance is critical for ensuring adequate polymerization and material properties.