Effect of dentin bonding agent diffusing through dentin slices on the reactive oxygen species production and apoptosis of pulpal cells

Abstract

Dentin bonding agents (DBAs) are cytotoxic to dental pulp cells. This study aimed to evaluate the effects of three DBAs (Optibond Solo Plus, Op; Clearfil SE Bond, SE; and Xeno III, Xe) after diffusion through 0.2-mm or 0.5-mm dentin slices on reactive oxygen species (ROS) production and apoptosis in dental pulp cells. Methods: The amounts of DBAs diffusing through 0.2-mm or 0.5-mm dentin slices were quantified using a UV-Vis spectrophotometer. The effects of diffused DBAs on ROS production and viability of dental pulp cells were investigated using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay on Days 1 and 2. Flow cytometric analysis and double staining of treated dental pulp cells with Annexin V-fluorescein isothiocyanate (V-FITC) and propidium iodide (PI) were performed on Day 2. Results: Xe showed greatest diffusion through dentin slices after 8-hour period, followed by SE and Op. Dental pulp cells produced a lesser amount of ROS, when treated with DBAs diffusing through a 0.5-mm dentin slice than through a 0.2-mm dentin slice for the same period of time. A small proportion of cells were TUNEL-positive after treatment with any of the three diffused DBAs. Annexin V-FITC/PI staining identified apoptotic cells; cell survival was higher in those cells treated with DBAs diffusing through a 0.5-mm dentin slice than through a 0.2-mm dentin slice. Conclusion: The three DBAs after diffusion through 0.2- or 0.5-mm dentin slice still exhibit cytotoxicity to dental pulp cells. However, the 0.5-mm dentin slice is found to be a better barrier than the 0.2-mm dentin slice to protect dental pulp cells from DBA-induced cytotoxicity.

Keywords

• apoptosis
• cytotoxicity
• dentin bounding agent
• dental pulp cell
• dentin slice
• reactive oxygen species