Análise in vitro do aumento de temperatura pulpar e em resinas compostas bulk-fill durante a utilização de fotopolimerizadores LED contemporâneos e laser

Abstract

To evaluate in vitro the effects of laser and contemporary LED light curing units on real-time pulp temperature (PT) change under simulated intraoral conditions. Materials and Methods: The study was divided into three experiments. Experiment 01: The temperature produced by Monet laser (1 and 3s, AMD Lasers), Valo Grand (3 and 10s, Ultradent), DeepCure (10s, 3M), PowerCure, (3 and 10s, Ivoclar) and PinkWave (10s, Vista Dental Products) were measured at the bottom of 2 mm deep × 6 mm wide cylindrical specimens made with Filtek Universal (3M), Tetric Evoceram (Ivoclar) and Transcend (Ultradent). ΔT values were subjected to two-way ANOVA and hardness values (VH) were evaluated at the top and bottom using ANOVA and Scheffe's post hoc test (p < 0.05). Experiment 02: After the Ethics Committee approval (#2021-5703), the PT increase in non-retentive Class I and V preparations in maxillary molars was evaluated when the preparations were exposed to the laser emitted by the Monet (1 and 3s, AMD Lasers), or to light emitted by PinkWave (3 and 10s, Vista Dental Products), Valo Grand (3 and 10s, Ultradent), PowerCure (3 and 10s, Ivoclar) and SmartLite Pro (10s, Dentsply Sirona). The baseline was kept at 32°C. Two thermocouples (type T) were inserted inside the pulp chamber through the roots, being positioned close to the pulp horn and on the buccal wall near the Class V cavity. The water flow was adjusted to 0.026 mL/min and real-time temperature data was collected (every 0.5s). PT measurements were obtained with the LCU tip 0 and 6 mm away from the tooth surface. The effect of pulp flow was compared using one-way ANOVA followed by Scheffe's post hoc test and ΔT values were submitted to two-way ANOVA. Experiment 03: The cavities were filled with Filtek One Bulk Fill (3M), Filtek Bulk Fill Flow (3M), Tetric PowerFill (Ivoclar) or Tetric Power Flow (Ivoclar). The tooth was exposed to Monet (1 and 3s, AMD Lasers), PowerCure (3 and 20s, Ivoclar), PinkWave (3 and 20s, Vista Dental Products), Valo X (5 and 20s, Ultradent) and SmartLite Pro (20s, Dentsply Sirona). ΔT data was subjected to one-way ANOVA followed by Scheffe's post hoc test. Results: Experiment 01: The greatest temperature increases occurred for Transcend without significant differences between Filtek Universal and Tetric Evoceram (p = 0.9756). Transcend achieved the highest VH values. PinkWave 10s produced the highest temperature rise and Monet 1s produced the lowest rise and lowest VH bottom:top ratio. Experiment 02: Monet 3s and PinkWave 10s produced the highest PT rise in the Class I cavity. Simulated pulp flow did not influence the PT rise. Overall, cavities exposed at the 0 mm distance had higher ΔT values than at the 6 mm distance. Experiment 03: Monet 1s and PinkWave 20s provided the lowest and highest amount of energy, respectively. Valo X and PinkWave used for 20s produced the highest ΔT values. Monet 1s, PinkWave 3s, PowerCure 3s and Monet 3s produced the lowest ΔT values. No significant differences were found between the RBCs. Conclusion: the temperature increase is related to the amount of energy delivered to the tooth and the curing light's ability to be positioned directly over the restoration; the translucency of RBCs affects the increase in temperature and hardness (VH); simulated pulpal flow of 0.026 mL/min has no significant effect on PT changes; increasing the distance between curing light tip and tooth surface reduced the

temperature rise for most curing lights; and short exposure modes do not produce increases in PT due to the lower amount of energy released.