The heat emitted from some QTH and LED light curing units in consecutive activations. A laboratory assessment.

The temperature rises produced by two Quartz-Tungsten-Halogen (QTH) bulb and four solid-state light emitting diode (LED) light curing units (LCU's) was measured on five separate occasions following (i) activation for 40 seconds and (ii) three consecutive activations of 40 seconds. For both periods of activation evaluated the Luxor QTH LCU exhibited significantly (P<0.01) lower temperature rises (1.2 (0.2) - 2.5 (0.4) degrees C) than all other LCU's. In the case of the consecutive applications the temperature rises, for the other units, exceeded known threshold temperaturesforpulpitis to be risked.