Efficacy of 5- and 10-Second High Intensity Led Exposures

METHODS: Three commercial light-cured composites (all CQ-based) were used (shade A2): difficult to cure (Heliomolar (HEL)), relatively easy to cure (Herculite (HER)); easy to cure (Filtek Supreme Plus (FIL)). Lights used: high intensity blue LED (5- and 10-s exposures) and Bluephase 16i in Hi Power mode (Ivoclar), LEDemetron2 (Kerr); QTH (Optilux 501, Kerr) 40s for Heliomolar, Herculite, 20s for Filtek. Brass rings (6mm ID, 2mm high) were filled with composite paste, covered with Mylar, and pressed flat while on the diamond element of an attenuated total reflectance unit in a Fourier Transform infrared spectrometer. Light guide ends were rigidly held 2 mm from the Mylar and spectra were recorded (16 scans, 2cm^-1) with the light off, and then 5 min after light exposure. Monomer conversion values were determined from infrared spectra using standard peak-ratio techniques. Within each composite type, conversion values were compared between different exposures of each LED unit and the recommended QTH exposure using ANOVA and Dunnett's t-test using QTH value as "control." N = 5, pre-set alpha = 0.05.

RESULTS:

Conversion values relative to the QTH exposure were as follows:

CONCLUSION: At 2 mm depth, all five-second and most 10-second exposures from high intensity blue LED lights did not provide equivalent conversion as when using a QTH light for manufacturer recommended times.