Mineral trioxide aggregate (MTA) is a calcium-silicate-based material introduced in the 1990s for perforation repair, pulp capping, apical plugs, and root-end filling. It remains a reference material. Modern bioceramic putties and cements (e.g., BioDentine, EndoSequence BC RRM, NeoMTA) share the calcium-silicate chemistry but offer faster set times, improved handling, and premixed formulations.
Typical composition: tricalcium silicate, dicalcium silicate, tricalcium aluminate, bismuth oxide (or zirconium oxide in modern formulations for radiopacity). On mixing with water, calcium silicate hydrate and calcium hydroxide are formed — the latter accounts for the high pH and bioactivity.