Effects of Radiopaque Double Antibiotic Pastes on the Proliferation, Alkaline Phosphatase Activity and Mineral Deposition of Dental Pulp Stem Cells

Arch Oral Biol. 2020 May 13;117:104764. doi: 10.1016/j.archoralbio.2020.104764. Online ahead of print.

Abstract

Objective: The aim of this study was to investigate the effects of two radiopaque agents, barium sulfate (BaSO4) or zirconium oxide (ZrO2) in double antibiotic paste (DAP), on the proliferation and mineral deposition of human dental pulp stem cells (DPSC).

Materials and methods: Radiopaque antimicrobial medicaments composed of methylcellulose (MC) thickening polymer with BaSO4 or ZrO2 and either 1 or 5 mg/mL DAP (equal portions of metronidazole and ciprofloxacin) were used to investigate DPSC proliferation after 3 days, and alkaline phosphatase (ALP) activity and mineral deposition after 7 and 14 days. Radiopaque agents without DAP and Ca(OH)2 were used as controls.

Results: MC-BaSO4 DAP and MC-ZrO2 DAP at 1 or 5 mg/mL had no adverse effect on DPSC proliferation, compared to the media and MC controls. MC-ZrO2 (DAP-free) greatly increased ALP activity after 7 days. DPSC mineral deposition was modestly reduced at 7 days by MC-BaSO4 DAP and MC-ZrO2 DAP, but not by DAP-free radiopaque agents, and was most reduced by 5 mg/mL DAP in the 14-day cultures.

Conclusions: MC-BaSO4 or MC-ZrO2 medicaments containing up to 5 mg/mL of DAP supported the proliferation and early osteogenic differentiation of DPSC. Low DAP concentrations and short culture times led to more favorable effects on ALP activity and mineral deposition by DPSC. The findings suggest that radiopaque agents added for the purpose of detecting whether medicaments occupy the full extent of the root canal may have clinical applications. Radiopaque antibiotic medicaments containing low DAP concentrations may be an alternative to Ca(OH)2 for regenerative endodontic procedures.

Keywords: Alkaline phosphatase; Barium sulfate; Dental pulp stem cells; Double antibiotic paste; Mineral deposition; Zirconium oxide.