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

Abstract

To analyse the influence of H2 O2 on pulp repair through osteocalcin and osteopontin immunolabelling and in cellular defence by using the antireactive oxygen species (ROS) antibody. The maxillary molars of 50 rats were treated with 35% H2 O2 (Ble groups) or placebo gel (control groups). At 0h and 2, 7, 15 and 30days (n=10hemimaxillae), 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). The Ble group had necrosis in the coronal pulp at 0h and in the occlusal third of the coronal pulp at 2days; at 7, 15 and 30days, no inflammation was noted similar to the controls (P>0.05). Osteocalcin was absent in the Ble at 0h, moderate at 2days and increased thereafter, differing from the controls at all two periods (P<0.05). Osteopontin was higher principally at 7 and 15days in Ble groups, but differing with control groups from 2days after bleaching (P<0.05). The Ble group had more ROS-positive cells in the pulp at 7 and 15days (P<0.05). Tertiary dentine was observed at 7days, increasing thereafter (P<0.05). 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 H2 O2 .