Direct and Indirect Effect of Chlorhexidine on Survival of Stem Cells from the Apical Papilla and Its Neutralization

Matthias Widbiller; Riyadh I Althumairy; Anibal Diogenes

doi:10.1016/j.joen.2018.11.012

Direct and Indirect Effect of Chlorhexidine on Survival of Stem Cells from the Apical Papilla and Its Neutralization

J Endod. 2019 Feb;45(2):156-160. doi: 10.1016/j.joen.2018.11.012.

Authors

Matthias Widbiller¹, Riyadh I Althumairy², Anibal Diogenes³

Affiliations

¹ Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, Texas; Department of Conservative Dentistry and Periodontology, University Hospital Regensburg, Regensburg, Germany.
² Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, Texas; Department of Restorative Dental Sciences, King Saud University, Riyadh, Saudi Arabia.
³ Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, Texas. Electronic address: diogenes@uthscsa.edu.

PMID: 30711171
DOI: 10.1016/j.joen.2018.11.012

Abstract

Introduction: Several irrigants have been used for disinfection in regenerative endodontic procedures including chlorhexidine (CHX). In this context, the antibacterial properties of disinfectants are mainly in focus of research even though they may have an undesirable impact on the fate of stem cells. In this study, we hypothesized that CHX has both a direct effect when applied to stem cells of the apical papilla (SCAPs) and an indirect effect when SCAPs are exposed to dentin previously conditioned with CHX.

Methods: Cell toxicity was evaluated in vitro using the CellTox green fluorescence assay (Promega, Madison, WI) and CellTiter-Glo (Promega) after SCAPs were exposed directly to a dynamic concentration range of CHX; apical papilla explant cultures were stained with ApopTag (Merck Millipore, Billerica, MA) after culture with CHX. Furthermore, standardized slabs from human dentin were treated with CHX and consecutively rinsed in EDTA, L-α-lecithin (Sigma-Aldrich, St Louis, MO), or L-α-lecithin followed by EDTA. After that, SCAPs were cultured on the slabs for 5 days, and cellular viability was determined (indirect effect). Data were treated nonparametrically and analyzed using the Krukal-Wallis test (P ≤ .05).

Results: Direct exposure of SCAPs to CHX highly affected cell viability at concentrations above 10^-3%, whereas lower concentrations had no adverse effect. During the initial 60 minutes, concentrations of 10^-2% CHX or higher resulted in early pronounced toxicity with a maximum effect within 15 minutes after exposure. Likewise, CHX-conditioned dentin slabs were detrimental to SCAP survival; however, the deleterious effects were completely reversed by neutralization with L-α-lecithin.

Conclusions: Chlorhexidine is toxic to SCAPs when applied directly or indirectly via conditioned dentin. If applied for a short time and neutralized by L-α-lecithin, it can be a gentle and cell-preserving disinfectant before endodontic regeneration.

Keywords: Chlorhexidine; dentin; endodontic regeneration; lecithin; stem cells; toxicity.

MeSH terms

Anti-Infective Agents, Local / administration & dosage
Anti-Infective Agents, Local / adverse effects*
Cell Survival / drug effects*
Cells, Cultured
Chlorhexidine / administration & dosage
Chlorhexidine / adverse effects*
Chlorhexidine / antagonists & inhibitors
Chlorhexidine / toxicity
Dental Papilla / cytology*
Disinfectants / administration & dosage
Disinfectants / adverse effects*
Disinfectants / antagonists & inhibitors
Disinfectants / toxicity
Dose-Response Relationship, Drug
Humans
Lecithins / pharmacology
Regenerative Endodontics
Root Canal Irrigants / administration & dosage
Root Canal Irrigants / adverse effects*
Root Canal Irrigants / toxicity
Stem Cells / drug effects*
Tooth Apex / cytology*

Substances

Anti-Infective Agents, Local
Disinfectants
Lecithins
Root Canal Irrigants
Chlorhexidine