There are 2 types of setting reaction, initial and final or chemically stable setting reaction. OrthoMTA’s initial setting time is 180 minutes and final setting time is 360 minutes. It may be a disadvantage if the setting time is short for othrograde obturation technique. Short setting time is only advantageous for retrofilling procedure. BioMTA has this product too, RetroMTA, which sets in 3 minutes.