Method: Pulp chambers of two extracted sound human maxillary central incisors (HMCI 1 and 2), from the same donor, received a K-type thermocouple connected to a digital thermometer. Six groups were assigned according to different treatments: G1- HMCI 1 and 2 + LED photoactivation (LED) (control); G2- HMCI 1 and 2 + 35% hydrogen peroxide (35HP) + LED; G3- HMCI 1 + microhybrid composite-resin restoration (MC) + LED; G4- HMCI 2 + low shrinkage microhybrid composite-resin restoration (LSC) + LED; G5- HMCI 1 + MC + 35HP + LED; G6- HMCI 2 + LSC +35HP + LED. Room temperature (26±1°C) was considered as initial, and each group received four cycles of light activation. Highest temperature in each cycle of light activation was recorded, and temperature variation (DT) calculated. Data were analysed by Kruskal-Wallis and Dunn’s tests (p<0.05).
Result: The highest mean of DT was observed at G4 (2.82°C) and the lowest one at G5 (1.40°C). Significant differences were found between G1 and G5, and G4 and G5.
Conclusion: The presence of composite-resin restoration, as well the type of restorative material, significantly interfered in pulp chamber DT when performing tooth bleaching with LED activation, reducing the temperature rises.