Attachment Ability of Human Apical Papilla Cells to Root Dentin Surfaces Treated with Either 3Mix or Calcium Hydroxide

Abstract

Introduction: Tissue regeneration and root continuation are the ultimate goals in regenerative endodontics. Apical papilla cells (APCs) have been hypothesized to play roles in those processes. Therefore, preservation of cell vitality and promoting initial cell attachment seem to be crucial steps. The purposes of this study were to investigate the attachment ability and morphology of viable human APCs by using fibronectin immunofluoresence, alamarBlue assay, and scanning electron microscopy, when APCs were grown on human root dentin surfaces treated with 3Mix or calcium hydroxide (Ca(OH)2) at different concentrations.

Methods: Human root dentin slices were divided into 6 groups: (1) control, (2) 3Mix 0.39 μg/mL, (3) 3Mix 100 μg/mL, (4) 3Mix paste, (5) Ca(OH)2 1 mg/mL, and (6) Ca(OH)2 1000 mg/mL. All samples were separately treated for 7 days and final rinsed with 17% EDTA. Then primary human APCs were seeded. Fibronectin immunofluorescence was used to evaluate the attachment ability of APCs on treated dentin. A vitality assay by using alamarBlue was monitored at specific time intervals. The morphology of the cells on the dentin was observed under scanning electron microscopy.

Results: The lowest number of fibronectin-positive cells was observed on root dentin treated with 3Mix paste (P < .05). The 3Mix at 0.39 and 100 μg/mL did not affect the amount of APC attachment, whereas the viability of APCs on the dentin surface was significantly lower in the 100-μg/mL 3Mix-treated group than in the negative control group (P < .05). Both concentrations of Ca(OH)2 induced APC attachment (P < .05). Moreover, only cells grown on the surfaces treated with Ca(OH)2 exhibited cytoplasmic processes.

Conclusions: Human root dentin treated with 3Mix paste had significantly lower APC attachment. The 3Mix at 0.39 μg/mL and 100 μg/mL had no significant negative effect on APC attachment on dentin. Higher numbers of cells attaching on dentin were observed in calcium hydroxide-treated groups.

Keywords: 3Mix; Apical papilla cells; attachment; calcium hydroxide.