In vitro pulp chamber temperature rise from irradiation and exotherm of flowable composites

Objective. The aim of this study was to investigate the pulpal temperature rise induced during the polymerization of flowable and non‐flowable composites using light‐emitting diode (LED) and halogen (quartz–tungsten–halogen) light‐curing units (LCUs). Methods. Five flowable and three non‐flowable composites were examined. Pulpal temperature changes were recorded over 10 min in a sample primary tooth by a thermocouple. A conventional quartz–tungsten–halogen source and two LEDs, one of which was programmable, were used for light curing the resin composites. Three repetitions per material were made for each LCU. Results. There was a wide range of temperature rises among the materials ( P < 0.05). Temperature rises ranged between 1.3 °C for Filtek Supreme irradiated by low‐power LED and 4.5 °C for Grandio Flow irradiated by high‐power LED. The highest temperature rises were observed with both the LED high‐power and soft‐start LCUs. The time to reach the exothermic peak varied significantly between the materials ( P < 0.05). Conclusions. Pulpal temperature rise is related to both the radiant energy output from LCUs and the polymerization exotherm of resin composites. A greater potential risk for heat‐induced pulp damage might be associated with high‐power LED sources. Flowable composites exhibited higher temperature rises than non‐flowable materials, because of higher resin contents.