Reactivity and Environmental Factors

Hydrated mineral trioxide aggregate (MTA) is composed of calcium silicate hydrate, calcium hydroxide, ettringite, monosulphate and bismuth oxide together with unreacted tricalcium and dicalcium silicate. The presence of calcium hydroxide, which is usually leached out of the material, renders MTA reactive and thus susceptible to changes as a result of the environment in which it is placed. The specific alterations to the material will vary depending on its use and thus its relationship with other materials, tissues and fluids