The Effect of Mineral Trioxide Aggregate on Odontogenic Differentiation in Dental Pulp Stem Cells

Introduction: This study aimed to identify the early genetic changes related to odontogenic differentiation when mineral trioxide aggregate (MTA) is applied to dental pulp stem cells (DPSCs). Methods: Odontogenic-differentiated cells (induced DPSCs) were obtained by culturing DPSCs in odontoinduction medium for 14 days. Thereafter, MTA in Teflon tubes was applied to the induced DPSCs and uninduced cells. Cells exposed to empty tubes were used as negative controls. The total RNA was extracted from the MTA treated and MTA untreated cells 1 and 3 days after tube application and assessed by microarray analysis. The key results were confirmed selectively by reverse-transcription polymerase chain reaction. We also performed a gene set enrichment analysis. Results: In microarray analysis, although the expression levels of 460 genes were changed more than 2-fold in MTA-treated, uninduced DPSCs after 1 day, only 39 genes were altered in MTA-treated, induced DPSCs. In the odontoinduction medium induced, MTA-treated DPCs, the value of correlation was 0.993 on 1 day and 0.986 on 3 day compared with 0.970 on 1 day and 0.975 on 3 day in the uninduced, MTA-treated DPSCs. Gene set enrichment analysis revealed that MTA significantly up-regulated gene sets involved in cell migration, the response to transforming growth factor beta 1, and the inflammation pathway in the uninduced DPSCs, whereas in the induced DPSCs it only up-regulated genes involved in cell migration after 1 day. Conclusions: This result shows that MTA stimulates the odontogenic differentiation of DPSCs, and the effects of MTA are drastically increased in uninduced pulp cells compared with odontogenic-differentiated cells. (J Endod 2013;39:242-248)