Comparative Analysis of the Cytotoxic Effects of Modified Triple Antibiotic Hydrogel: Insights From Experimental...

The effectiveness of intracanal medicaments (ICMs) in root canal therapy is critical for successful dental treatments, yet their cytotoxic effects pose significant challenges. This research uses zebrafish embryos and dental pulp stem cells (DPSCs) to identify the optimal concentration that balances antibacterial efficacy with minimal toxicity.

This study aims to address the need for effective ICMs in dentistry by formulating and assessing the embryotoxicity and cytocompatibility of a novel carrageenan-based modified triple antibiotic paste (MTAP) hydrogel at different concentrations (1, 5, and 10 mg/mL) using a zebrafish model and cell culture assay.

The hydrogel was formulated by combining antibiotic solutions (ciprofloxacin, metronidazole, and amoxicillin) with carrageenan and xanthan gum. Zebrafish embryos were exposed to varying concentrations of MTAP hydrogel, chlorhexidine (CHX), calcium hydroxide (CaOH₂), and plain carrageenan to assess developmental toxicity, survival rate, heart rate, hatching rate, and macrophage migration. The cytotoxicity against DPSCs was examined within a timeframe of 6, 24, and 72 hours with the use of the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide (MTT) assay.

The analysis revealed developmental toxicity with malformations observed at higher concentrations of MTAP hydrogel, CaOH₂, and CHX medicaments, indicating potential toxicity. Significant impacts on survival, heart rate, and hatching rate were noted in the CaOH₂ and CHX groups, as well as at higher MTAP hydrogel concentrations, emphasizing the importance of dosage considerations. The neutral red assay confirmed toxicity, with macrophage migration observed in CaOH₂, CHX, and higher MTAP hydrogel concentrations. Lower concentrations, particularly at 1 mg/mL, showed no adverse effects on zebrafish embryos and larvae. These findings align with cell viability investigations, which demonstrated that higher antibiotic concentrations resulted in decreased cell proliferation and viability over time. Conversely, at a lower concentration of 1 mg/mL, cell proliferation notably increased after 72 hours. Plain MTAP and CHX exhibited the highest toxicity levels in the MTT assay.

The study concludes that while higher concentrations of MTAP hydrogel exhibit toxic effects, the hydrogel at 1 mg/mL demonstrates no adverse impact on zebrafish embryos, larvae, and DPSCs. These findings underscore the necessity of optimizing ICM concentrations to balance antibacterial efficacy and minimal cytotoxicity.