The cytotoxic effects of various endodontic irrigants on the viability of dental mesenchymal stem cells
Australian Endodontic Journal. 2022;48(2):305-312.
ABSTRACT
This study aimed to evaluate cytotoxic effects of various irrigation solutions used in regenerative endodontic treatments (RETs) on mesenchymal stem cells, and further examine the long-term effect of hypochlorous acid (HOCl) on the cell viability and alkaline phosphatase (ALP) activity. Stem cells were exposed to various concentrations of NaOCl, EDTA, chlorhexidine (CHX), etidronic acid (HEDP)/NaOCl combination and HOCl. HOCl was tested for its effects on ALP activity up to 21 days. Additionally, cell viability was measured fluorescently using calcein AM. The most cytotoxic irrigant was CHX even with the lowest concentration. NaOCl and HEDP/NaOCl with 1:100 dilution decreased viability to around 40%. HOCl showed the lowest cytotoxicity among all tested irrigants. HOCl also showed no significant reduction in ALP activity compared with the controls. The cytotoxicity of endodontic irrigants was time and concentration dependent. HOCl demonstrated promising results regarding viability and ALP activity, since RETs require host stem cell survival.
KEYWORDS
cell survival · chlorohexidine · hypochlorous acid · stem cells · sodium hypochlorite
STUDY SUMMARY
This cell-culture study exposed dental mesenchymal stem cells to a range of concentrations of five endodontic irrigants and followed the effect of hypochlorous acid on cell viability and alkaline phosphatase activity for up to 21 days. Chlorhexidine was the most cytotoxic irrigant even at the lowest concentration, sodium hypochlorite and the etidronic acid combination reduced viability to around 40% at 1:100 dilution, and hypochlorous acid showed the lowest cytotoxicity with no significant reduction in alkaline phosphatase activity. Cytotoxicity depended on both exposure time and concentration under these laboratory conditions.