White mineral trioxide aggregate induces migration and proliferation of stem cells from the apical papilla

Regenerative endodontic protocols recommend white mineral trioxide aggregate (WMTA) as a capping material because of its osteoinductive properties. Stem cells from the apical papilla (SCAP) are presumed to be involved in this regenerative process, but the effects of WMTA on SCAP are largely unknown. Our hypothesis was that WMTA induces proliferation and migration of SCAP.

Here we used an unsorted population of SCAP (passages 3-5) characterized by high CD24, CD146, and Stro-1 expression. The effect of WMTA on SCAP migration was assessed by using transwells, and its effect on proliferation was determined by the WST-1 assay. Fetal bovine serum (FBS) and calcium chloride-enriched medium were used as positive controls.

The SCAP analyzed here showed a low percentage of STRO-1+ and CD24+ cells. Both set and unset WMTA significantly increased the short-term migration of SCAP after 6 hours (P < .05), whereas calcium chloride-enriched medium did after 24 hours of exposure. Set WMTA significantly increased proliferation on days 1-5, whereas calcium-enriched medium showed a significant increase on day 7, with a significant reduction on proliferation afterwards. SCAP migration and proliferation were significantly and steadily induced by the presence of 2% and 10% FBS.

Collectively, these data demonstrate that WMTA induced an early short-term migration and proliferation of a mixed population of stem cells from apical papilla as compared with a later and longer-term induction by calcium chloride or FBS.