Open AccessThe chemical composition of mineral trioxide aggregate
Author(s) -
Josette Camilleri
Publication year - 2008
Publication title -
journal of conservative dentistry/journal of conservative dentistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.533
H-Index - 31
eISSN - 0974-5203
pISSN - 0972-0707
DOI - 10.4103/0972-0707.48834
Subject(s) - mineral trioxide aggregate , ettringite , calcium hydroxide , calcium silicate hydrate , aluminate , materials science , portland cement , calcium silicate , cement , hydrate , mineralogy , chemical engineering , metallurgy , chemistry , composite material , dentistry , medicine , organic chemistry , engineering
Mineral trioxide aggregate (MTA) is composed of Portland cement, with 4:1 addition of bismuth oxide added so that the material can be detected on a radiograph. The cement is made up of calcium, silicon and aluminium. The main constituent phases are tricalcium and dicalcium silicate and tricalcium aluminate. There are two commercial forms of MTA, namely the grey and the white. The difference between the grey and the white materials is the presence of iron in the grey material, which makes up the phase tetracalcium alumino-ferrite. This phase is absent in white MTA. Hydration of MTA occurs in two stages. The initial reaction between tricalcium aluminate and water in the presence of calcium sulphate results in the production of ettringite. Tricalcium and dicalcium silicate react with water to produce calcium silicate hydrate and calcium hydroxide, which is leached out of the cement with time.