Mesenchymal Stem Cells Promote Hard-tissue Repair after Direct Pulp Capping

IntroductionThe aim of this study was to investigate the potential of autologous mesenchymal bone marrow stem cells (BMSCs) to promote hard-tissue formation after direct pulp capping procedures.Materials and MethodsBone marrow was aspirated from the iliac crest of healthy dogs of nonspecific race. Mononuclear cells were obtained using the Histopaque (Sigma-Aldrich, St Louis, MO) protocol and cultured for 21 days. Direct pulp capping procedures were performed in posterior teeth, and then mineral trioxide aggregate (MTA), hydroxyapatite/tricalcium phosphate, or BMSCs were used as direct pulp capping agents. After 3 months, animals were sacrificed, and jaw segments were processed for radiographic examination using cone-beam computed tomography scanning and histologic examination to assess the formation of a hard-tissue barrier according to a scoring system.ResultsThe longitudinal and cross-sectional radiophotographs and histologic sections confirmed the formation of an evident calcific barrier after direct pulp capping with MTA and BMSCs. Statistical analysis of the scores given for radiographic and histologic calcific bridge formation showed that both MTA and BMSCs had a comparable tendency to produce a hard-tissue barrier that was significantly higher than hydroxyapatite tricalcium phosphate (P < .05).ConclusionsAutologous mesenchymal BMSCs were able to promote hard-tissue formation after direct pulp capping procedures.