Biological Performance of a Nitrofurantoin-Based Triple Antibiotic Paste for Regenerative Endodontics

This study evaluated an experimental triple antibiotic paste (EXP) composed of nitrofurantoin (4 mg/g), ciprofloxacin (1 mg/g) and metronidazole (5 mg/g) for regenerative endodontic procedures (REPs), using calcium hydroxide [Ca(OH)₂] as a reference.

EXP, commercial Hoshino pastes containing ciprofloxacin, metronidazole and minocycline at 1 or 5 mg/g, and a Ca(OH)₂ paste were compared in human dental pulp stem cells exposed for 24 h to 0.2 g/mL extracts. Cytotoxicity was assessed by XTT, Neutral Red, Crystal Violet and qualitative Live/Dead imaging. The concentrations of 27 cytokines, chemokines and growth factors in culture supernatants were quantified by multiplex immunoassay. Data were analysed using Kruskal-Wallis with Dunn-Holm post hoc testing.

EXP maintained approximately 75% metabolic activity and showed a less severe cytotoxic profile than the Hoshino formulations. In Neutral Red, EXP preserved significantly greater lysosomal integrity than Hoshino 1, Hoshino 5 and Ca(OH)₂. Live/Dead imaging supported greater preservation of viable cells with EXP. Hoshino 5 significantly reduced IL-2, IL-5 and IL-8, whereas Ca(OH)₂ increased IL-6 and reduced IL-1β, IL-15, IL-17, VEGF and MIP-1β. Hoshino 1 and EXP only differed from untreated control on IP-10, and no differences occurred among medicament-treated groups.

The nitrofurantoin-based EXP paste demonstrated comparatively improved cytocompatibility toward DPSCs relative to the conventional Hoshino formulations and greater preservation of cell viability than the tested Ca(OH)₂ paste under the present experimental conditions. Together with its previously demonstrated antimicrobial activity, these findings support EXP as a promising candidate for further investigation in REPs.