Osteoblasts interact with MTA surfaces and express Runx2

Objective. Periradicular healing involves osteoblasts that are dependent on the Runt-related transcription factor 2 (Runx2). The purpose of this study was to determine if mineral trioxide aggregate (MTA) root-end filling materials support Runx2 expression in osteoblasts. Study design. Human alveolar bone cells were grown on alternative formulations of MTA. Cell-surface interactions were visualized by scanning electron microscopy. Gene expression was examined by reverse-transcription polymerase chain reaction and Western blot analysis. Results. Cells attached to and spread out on MTA surfaces within 24 hours and formed a collagenous matrix overlay within 1 week of growth. Runx2 expression increased from low levels in the 24-hour cultures to an abundance during 2 weeks of growth and differentiation on MTA surfaces and on tissue culture plastic controls. The cells responded similarly to ProRoot, Tooth-Colored MTA, and MTA mixed with local anesthetic solution. Conclusion. Mineral trioxide aggregate materials support cell attachment and Runx2 expression in osteoblasts. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009; 107: 590-596)