An In Vitro Tube Model for Cell Biocompatibility Study of Capping Materials for Regenerative Endodontics.

Abstract

Introduction: Cell-based pulp regeneration utilizes capping materials underneath a final restoration to seal the tooth after delivering cells into the canal system. Studying the immediate biocompatibility of materials with injected cells has been challenging. This study aimed to utilize a tube model to observe cell response directly and conveniently to the capping materials in a cell culture in vitro system.

Methods: A tapered plastic tube (14 mm in length, 2 mm diameter of the apex opening) to simulate root canal space was filled with fluorescence-labeled dental pulp cells mixed in fibrin gel and the larger end sealed with various capping materials including Mineral Trioxide Aggregate (MTA), Biodentine, hydroxyapatite-tricalcium phosphate (HA-TCP), composite, and glass ionomer. The tube was placed in wells of culture plates and incubated for various times in vitro and observed under the microscope for cell morphological changes. pH changes within the tube were monitored over time.

Results: Both fresh MTA and Biodentine caused adverse response to the cells in the tube. Only a few normally growing cells were observed at the apical end. Composite or glass ionomer appeared better tolerated by cells. HA-TCP mixed in fibrin gel demonstrated the highest compatibility with cells; however, using HA-TCP to separate cells from fresh MTA or Biodentine did not reduce the negative effect of these 2 calcium silicate cements. The pH increased within the tube may explain the observed toxicity.

Conclusions: Using HA-TCP mixed in fibrin gel as a capping material appears highly biocompatible to cells while fresh MTA and Biodentine are not.