Abstract
Regenerative endodontic procedures rely on the delivery of mesenchymal stem cells into the root canal and on the effect of local growth factors from the dentin and blood clot. The aim of this study was to assess the effect of dentin conditioning with ethylenediamine tetraacetic acid (EDTA) and diode lasers with different wavelengths (808 nm and 980 nm) on the expression of odontoblast-like cell markers. Forty dentin cylinders were divided into four groups according to the irrigation protocol: EDTA, EDTA + 808 nm diode laser, EDTA + 980 nm diode laser, and phosphate-buffered saline as the control group. Dental pulp stem cells were seeded into the previously conditioned cylinders and incubated for 14 days. The quantitative real-time polymerase chain reaction was used to evaluate the expression of dentin sialophosphoprotein (DSPP), dentin morphoprotein-1 (DMP-1), and transforming growth factor-beta 1 (TGF-β1). Data analysis was performed using the Kruskal-Wallis test. The activation of EDTA with 980 nm and 808 nm diode lasers resulted in lower DSPP and DMP-1 expression than that for EDTA alone (p < 0.05 and p < 0.01, respectively). The expression of TGF was similar among all groups. The highest level of expression of odontoblast-like differentiation markers was observed with EDTA alone. However, the use of an 808 nm diode laser during EDTA irrigation reduced the expression of odontoblastic differentiation markers.