Degree of conversion of translucent- and bleach-shade composites

Method: Five disks measuring 8mm in diameter x 0.5mm in thickness were made for a translucent, a bleach, and a dentin A3 shade of three different commercially available CRs brands (Z350XT, 3M ESPE; Empress Direct, Ivoclar Vivadent; Opallis, FGM). Disks were light-cured with a quartz-tungsten halogen light (QTH, Demetron LC, Demetron), a wide spectrum light-emiting diode (LED_LS, Bluephase G2, Ivoclar Vivadent), or a conventional light-emiting diode (LED, Emitter B, Schuster). After 24h the DC of the CRs disks were measured using FTIR-ATR spectroscopy, and the data analyzed using ANOVA and Tukey test (5%).   Result: For the translucent shades, the DC was significantly reduced when light-cured with the conventional LED as compared to the QTH and LED_LS. The bleach shades for brands Empress Direct and Opallis resulted in lower DC as compared to the dentin A3 shades, regardless of light-curing method. The neutral translucent shade (Empress Direct) showed lower DC as compared to the same brand’s dentin shade regardless of light-curing method used. In a similar manner, T-Neutral (Opallis) showed lower DC than Dentin A3 when light-cured with the LED.  Interestingly, the translucent shade CT (Z350XT) showed a higher DC than A3B when light-cured with the LED_LS.