Comment on "Laser-induced modulation of root dentin surface for growth factor release and enhanced stem cell...

Laser conditioning of dentin has been investigated as a strategy to enhance growth factor release and cellular responses in regenerative endodontics. The recent study by Mokhtari et al. reported laser-induced modulation of root dentin, increased transforming growth factor-beta 1 (TGF-β1) release, and enhanced alkaline phosphatase (ALP) activity. However, several methodological aspects should be considered when interpreting these findings and their potential clinical translation.

A critical analysis identifies important limitations in the experimental design. First, all laser-treated specimens were previously exposed to sodium hypochlorite, without a laser-only control, preventing the independent determination of the effect attributable to laser irradiation. Second, the concomitant increase in TGF-β1 release and ALP activity demonstrates an association but does not establish a causal mechanistic relationship, as no inhibition or neutralization experiments targeting TGF-β1 signaling were performed. Third, the use of mature dentin obtained from adult teeth limits direct extrapolation to immature permanent teeth, which are the clinical context emphasized in regenerative endodontics. In addition, the use of stem cells from human exfoliated deciduous teeth (SHED) does not fully represent endogenous cell populations involved in regenerative endodontics, and cellular migration or chemotaxis was not evaluated. Finally, differences in power and exposure time among wavelengths, together with the absence of calibrated power measurements and direct temperature monitoring, limit interpretation of dosimetry, dose-response relationships, and thermal safety.

The findings provide preliminary evidence that laser irradiation may modify dentin and influence growth factor release and cellular responses. Nevertheless, laser-only controls, mechanistic assessment of TGF-β1 signaling, immature dentin models, evaluation of cellular migration, calibrated laser dosimetry, and temperature monitoring are necessary to strengthen the mechanistic and translational evidence supporting laser-assisted regenerative endodontic applications.