Biocompatibility and pro-mineralization effect of tristrontium aluminate cement for endodontic use

BACKGROUND/PURPOSE: Tristrontium aluminate (S(3)A) is a hydraulic cement with setting behavior similar to that of mineral trioxide aggregate (MTA). This study examined the biological effects of S(3)A on mouse dental papilla cells (MDPs) in vitro and on rat exposed pulps in vivo. MATERIALS AND METHODS: Extracts of S(3)A and MTA were prepared by immersing each cement in ultrapure water. MDPs were cultured with S(3)A or MTA extracts, and cell proliferation was evaluated with a tetrazolium-salt assay. Attachment of MDPs on the set cements was examined with scanning electron microscopy (SEM). mRNA expression of bone morphogenic protein (Bmp2), osteocalcin (Oc) and osteopontin (Opn) in MDPs exposed to S(3)A or MTA extracts was determined with reverse transcription-quantitative polymerase chain reaction. Mineralized nodule formation was evaluated with Alizarin Red S staining. Simulated body fluid (SBF)-dipped S(3)A was examined with SEM and energy dispersive X-ray analysis (EDX). Exposed molar pulps of male Wistar rats capped with S(3)A or MTA were histologically examined. RESULTS: S(3)A extract did not inhibit proliferation of MDPs. Set S(3)A and MTA exhibited attachment of MDPs on their surface. S(3)A extract showed significantly higher mineralized nodule formation and mRNA expression of Bmp2, Oc, and Opn than did MTA extract. SBF-dipped S(3)A exhibited formation of surface precipitates, which were composed of Ca, P, Sr, and Al. Direct pulp capping with S(3)A and with MTA induced mineralized tissue repair of the exposed pulp. CONCLUSION: S(3)A possesses biocompatibility and pro-mineralization effects comparable to those of MTA.