Non-Thermal Atmospheric Pressure Plasma-Conditioned Root Dentin Promotes Attraction and Attachment of Primary Human Dental Pulp Stem Cells in Real-Time Ex Vivo

Abstract

This study investigated if non-thermal atmospheric pressure plasma (NTAPP) treatment of root dentin surfaces promotes human dental pulp stem cell (hDPSCs) adhesion. Freshly extracted human single-rooted teeth (n = 36) were decoronated and cut (first vertically, then horizontally) into root dentin slices (3 mm thick). Primary hDPSCs cultures were seeded onto slices randomly assigned to pretreatment groups (n = 9/group): NaOCl (1.5%), EDTA (17%) then NTAPP (Group I); NaOCl then NTAPP (Group II); NaOCl then EDTA (Group III); and NaOCl alone (Group IV). Cell viability and proliferation were measured using MTT assay with log-linear statistical analysis. Cell attachment and spreading morphologies on dentin slices (n = 3/group) were examined through scanning electron microscopy. Early cell adhesion events and subcellular activities were observed in real time by live-cell imaging through holotomographic microscopy. Cell viability and proliferation were significantly higher on NTAPP-treated dentin (p < 0.05), without interactions with EDTA (p > 0.05). The attachment, spreading, extensions and multiple layers of hDPSCs were heightened on NTAPP-treated dentin. Cell adhesion, spreading, and dentinal tubule penetration were hastened on NTAPP-treated dentin surfaces in real-time, with elevated subcellular activities and intracellular lipid droplet formation. NTAPP-treated root dentin surfaces support enhanced cellular responses, potentially promoting pulp-dentin regeneration.