Osteoblast cell attachment and gene expression on alternative formulations of Mineral Trioxide Aggregate

Background. The success of surgical Endodontics procedures is often dependent on the properties of the retrograde filling material. Providing a reliable apical seal is the main objective of a root-end filling material which is in direct contact with the periradicular tissues. Therefore, it should possess the highest possible biocompatibility in order for cells to spread and differentiate. Several studies have shown that Mineral Trioxide Aggregate (MTA) is an effective root-end filling material and appears to support the repair and regeneration of periapical tissues. Recently a newer tooth colored MTA material has become available. The purpose of this study is to determine if osteoblasts from human alveolar bone are able to attach and differentiate on the newer tooth colored MTA as on the older Pro-RootRTM MTA material, with commonly used mixing solutions.; Methods. A human alveolar bone chip was obtained from a routine oral surgical procedure and explants cultures were harvested after 3-4 weeks of outgrowth in alpha-minimum essential medium supplemented with fetal calf serum. These cells were seeded onto Grey and Tooth-colored ProRootRTM MTA disks which had been prepared with either water or local anesthetic solution. Glass cover slips served as controls. Replicate MTA disks were recovered after 1, 7 and 14 days of growth for the examination of cell morphology and spreading by scanning electron microscopy and for the analysis of gene expression by RT-PCR. Differentiation markers included RUNX2/Cbfa1 transcription factors and Collagen-1. GAPDH served as a control gene. Energy dispersive X-ray spectroscopy was used to analyze and compare the elemental composition of the both MTA powders.; Results. Energy dispersive X-ray spectroscopy showed that the Tooth-colored MTA resembled Grey MTA in chemical composition, but lacked alumina and had less iron. Scanning electron microscopy showed that the human alveolar bone cells attached and interacted with Grey and Tooth-colored MTA disks in a similar fashion. There was a similar increase in cell attachment and spreading over the MTA surfaces during 14 days of growth. General observation of the selected gene expression distribution was noted clearly where GAPDH was consistent throughout all the samples. RNA expression of both genes investigated (Cbfa-1 and COL-1), seemed to occur on both MTA variants in a similar fashion in all groups.; Conclusion. Results showed that both Grey and Tooth-colored ProRootRTM MTA prepared with either water or local anesthetic solution support the attachment and proliferation of cells found in human alveolar bone.