Comparative depths of cure among various curing light types and methods

Area of Science:

• Dental Materials Science
• Polymerization Technology
• Light Curing Technology

Background:

• Dental composites require adequate light curing for optimal physical properties and longevity.
• Various light curing units (LCUs) with different intensities and exposure modes are available, impacting polymerization depth.

Purpose of the Study:

• To evaluate and compare the depth of cure of commercial light-emitting diodes (LEDs) and Quartz Tungsten Halogen (QTH) curing lights.
• To assess the influence of different exposure regimens on the depth of cure for dental composites.

Main Methods:

• Evaluated depth of cure using penetration, scraping, and microhardness techniques.
• Tested ten exposure regimens across four commercial LCUs: Elipar FreeLight (FL), GC e-Light (EL), Elipar TriLight (TL), and Astralis 10 (AS), compared to a conventional QTH light (Max [Mx]).
• Statistical analysis included one-way ANOVA and Scheffe's post-hoc test.

Main Results:

• Most light curing regimens met the ISO depth of cure standard (1.5 mm), except for specific GC e-Light (EL) modes using microhardness.
• Elipar TriLight (TL1) demonstrated significantly greater depth of cure than the control (Mx) across all testing methods.
• GC e-Light (EL) modes generally resulted in significantly lower depths of cure compared to the control.

Conclusions:

• The depth of composite cure is dependent on the specific light curing unit and its exposure mode.
• High-intensity lights, such as Elipar TriLight, can achieve superior depths of cure.
• Penetration and scraping methods correlate with microhardness but may overestimate the actual depth of cure.