Method: Sixty sound human molars were collected after IRB approval. One 0.4mm-thick dentin disk was obtained from each tooth and mounted in artificial pulp chambers. The disks were distributed into 6 groups (n=10) after reading of the permeability in such a way that the mean permeability of the groups did not differ statistically. Odontoblast-like cells (MDPC-23) were seeded on the pulp surface of the disks and after 48 hours the following treatments were performed on the occlusal side: no treatment (negative control), 0.1M EDC, 0.3M EDC, 0.5M EDC, 0.05M cacodylate buffer and 29% hydrogen peroxide (positive control). All EDC solutions and cacodylate buffer were titrated to pH 5 with 0.01M HCl. Before application of the solutions, the occlusal dentin was acid etched (35% phosphoric acid) for 15s, followed by abundant rinsing and blot drying. The solutions were kept in contact with the dentin for 60s and then rinsed with deionized water for 10s. Cell viability was measured by MTT assay 24h after, and morphology by SEM. Data from cell metabolism were submitted to one-way analysis of variance complemented by Tukey’s tests for pairwise comparison of means (p=0.05).
Result: 0.1M EDC application did not influence the cellular metabolism (0.331±0.124), while 0.3M (0.385±0.092), 0.5M (0.396±0.131) and cacodylate buffer (0.470±0.101) solutions increased the SDH enzyme production compared to the negative control (0.330±0.114). Hydrogen peroxide applicaton drastically reduced the cell viabilty (0.022±0.025). No differences in cell morphology were identified among the groups, except for the positive control.
Conclusion: EDC application on 0.4mm-thick dentin disks was not cytotoxic to odontoblast-like cells (MDPC-23) up to the concentration of 0.5M.