Proliferation of rat molar pulp cells after direct pulp capping with dentine adhesive and calcium hydroxide

The aim was to evaluate the proliferation of pulp cells 1, 3 and 7 days after direct pulp capping with the dentine adhesive Gluma Comfort Bond (GCB) and to compare it with calcium hydroxide (Ca(OH)(2)). An occlusal cavity was prepared in 72 molar teeth of 36 Wistar rats. Then GCB or Ca(OH)(2) was placed on the exposed pulp. All cavities were restored with composite. After 1, 3 and 7 days, the animals were sacrificed. One hour prior sacrification, 5-bromo-2'-desoxyuridine (BrdU) was injected into the intraperitoneal cavity for immunohistological analysis of 18 animals. BrdU was incorporated into the DNA to tag proliferating cells using an antibody staining. Three animals served as controls and were not further treated. The number of the tagged cells was statistically analysed by comparing the results of the three groups. In 18 rats, routine histological analysis was performed in order to evaluate the pulp tissue for bacterial infection, inflammatory cells and necrosis. The marked cells were identified as fibroblasts, endothelial cells (after 1, 3 and 7 days) and Hohl cells (after 7 days). One day after capping, significantly more cells were stained in the GCB than in the Ca(OH)(2) group (p < 0.05). After 3 days, significantly more cells were stained in the GCB than in the Ca(OH)(2) and the control group (p < 0.016). Direct contact of GCB with pulp tissue leads to an increased formation of granulation tissue (fibroblasts, endothelial cells) because of an inflammatory reaction. This may be explained by missing antibacterial effect and foreign body reactions. Also, GCB may have a negative effect on Hohl cells.