In vitro temperature changes in the pulp chamber caused by laser and Quadwave LED-light curing units

Abstract

The study evaluated the pulp temperature (PT) increase in Class I and V preparations when exposed to the Monet Laser (for 1 and 3 s), the PinkWave (for 3 and 10 s), the Valo Grand (for 3 and 10 s), the PowerCure, (for 3 and 10 s) and the SmartLite Pro (for 10 s). Non-retentive Class I and Class V cavities were prepared in one molar fixed in an acrylic plate and positioned in a warm water bath. The PT baseline was kept at 32 °C to simulate physiological conditions. Two T-type thermocouples were inserted through the roots into the pulp chamber in two positions: close to the pulp horn and the buccal wall close to the Class V cavity. The water flow was adjusted to 0.026 mL/min, and real-time temperature data were collected every 0.5 s. PT measurements were made with the tip of the LCU 0 and 6 mm away from the tooth surface. The radiant exitance (mW/cm²) and radiant exposure (J/cm²) were calculated. One-way ANOVA compared the effect of the pulpal flow, and ΔT values were subjected to two-way ANOVA, followed by Scheffe's post hoc tests. The Monet Laser used for 3 s and the PinkWave used for 10 s produced the greatest PT rise in the Class I cavity. The simulated pulpal flow did not influence the PT rise. Overall, cavities exposed at the 0 mm distance had higher ΔT values than groups at 6 mm distance. The placement of a rubber dam for Class V restorations may prevent positioning LCUs directly over the cavity, which may affect the rise in PT.

Keywords: Dental curing lights; Laser; Light-emitting diode; Temperature.