Long-term treatment of dentine with triple antibiotic paste promotes stem cell viability and attachment

Successful regenerative endodontic procedures in dental treatment are critically associated with complete disinfection of the root canal and require irrigants and medicaments. One factor for consideration is the biocompatibility of the medicament as this can affect the intracanal dentine and subsequently the dental stem cell viability required for the repair of the dentine-pulp complex. This in vitro study investigated the effect of a 4-week treatment of calcium hydroxide [Ca(OH)₂] and triple antibiotic paste (TAP) on the irrigated radicular dentine by analysing dentine interaction with dental stem cells.

TAP consists of metronidazole, ciprofloxacin and minocycline. Dentine chips were prepared and treated with either Ca(OH)₂ or TAP for 4-weeks, irrigated by 1.5% sodium hypochlorite (NaOCl), rinsed with saline, followed by 17% ethylenediaminetetraacetic acid (EDTA). Dental pulp stem cells (DPSCs) cultured on the surface of the dentine chips were analysed on days 1, 3 and 7 of cell seeding for PrestoBlue viability assays, 6-diamidino-2 phenylindole (DAPI) staining and scanning electron microscopy (SEM). An independent t-test (SPSS software version 24.0) was used to statistically analyse the PrestoBlue assay data.

DPSCs grown from dentine treated with TAP showed significantly higher cell viability than the Ca(OH)₂ and control groups (p < 0.05). DAPI staining of the seeded DPSCs on the treated dental chips complemented the findings of the viability assay. SEM studies also revealed improvements in the cell spreading and attachment of DPSCs grown on TAP-treated dentine compared with Ca(OH)₂.

The treatment of dentine with TAP for 4 weeks provided a better microenvironment for the viability and attachment of DPSCs when compared to Ca(OH)₂.