The presence of osteocalcin, osteopontin and reactive oxygen species‐positive cells in pulp tissue after dental bleaching

Aim To analyse the influence of H 2 O 2 on pulp repair through osteocalcin and osteopontin immunolabelling and in cellular defence by using the antireactive oxygen species ( ROS ) antibody. Methodology The maxillary molars of 50 rats were treated with 35% H 2 O 2 (Ble groups) or placebo gel (control groups). At 0 h and 2, 7, 15 and 30 days ( n  = 10 hemimaxillae), the rats were killed and pulp tissue was evaluated using inflammation and immunolabelling scores (osteocalcin/osteopontin); ROS ‐positive cells were counted. Paired t ‐test and Wilcoxon signed‐rank test were used ( P  <   0.05). Results The Ble group had necrosis in the coronal pulp at 0 h and in the occlusal third of the coronal pulp at 2 days; at 7, 15 and 30 days, no inflammation was noted similar to the controls ( P  >   0.05). Osteocalcin was absent in the Ble at 0 h, moderate at 2 days and increased thereafter, differing from the controls at all two periods ( P  <   0.05). Osteopontin was higher principally at 7 and 15 days in Ble groups, but differing with control groups from 2 days after bleaching ( P  <   0.05). The Ble group had more ROS ‐positive cells in the pulp at 7 and 15 days ( P  <   0.05). Tertiary dentine was observed at 7 days, increasing thereafter ( P  <   0.05). Conclusions Post‐bleaching pulp repair was associated with increased osteocalcin over time. Osteopontin also participated in this process, and anti‐ ROS was involved in cellular defence against H 2 O 2 .