# Effects of photobiomodulation on human dental pulp stem cells treated with a bone xenograft: An in vitro study

## TL;DR

This study found that combining photobiomodulation with a bone substitute reduced the viability and bone-forming ability of dental stem cells.

## Contribution

The novel contribution is evaluating photobiomodulation's effect on stem cells treated with a bone xenograft in vitro.

## Key findings

- PBM restored cell migration in DPSCs treated with BO.
- PBM combined with BO reduced cell viability, alkaline phosphatase activity, and mineralization.
- The combination of BO and PBM was cytotoxic and impaired bone regeneration potential.

## Abstract

Background: Biocompatibility between bone cells and biomred for the process of osteogenesis. The aim of this study was to assess the effect of Photobiomodulation (PBM) in vitro on dental pulp stem cells (DPSCs) treated with Bio-Oss® (BO) bone substitute xenograft. Methods: DPSC cultures were obtained from third molars extracted from healthy volunteers and characterized by flow cytometry. The effects of PBM (5, 7, or 10 J/cm2) on DPSCs treated with BO (5 mg/ml) were assessed using cytotoxicity assays, viability staining, cell migration, alkaline phosphatase activity, and Alizarin red S staining. Results: PBM restored the lost migration ability of DPSCs treated with BO; however, this combined therapy was associated with significantly lower levels of DPSC viability, alkaline phosphatase expression, and mineralization compared to controls. Conclusion: PBM therapy did not improve the biocompatibility of DPSCs treated with BO bone substitute. The effect of interaction between these treatments seemed to be cytotoxic to DPSCs. Our results suggest that the interaction between BO and PBM therapy could impair bone regeneration.