MTA (mineral trioxide aggregate), ProRoot, Dentsply, is a versatile material that can be used to repair perforations, apexification, it can be used in pulpotomies, and apicoectomy as root end fillings and to apical seal zipped or wide open (blunderbuss) apices.
In the case below the foramen of tooth number 22 was zipped and the root filling was over-extended and control of the apical seal would have been very difficult with gutta percha alone. The root filling was retrieved and the apex was sealed with MTA and then back filled with gutta percha for a successful result.
In the case below from left to right: The first x-ray shows a short root filling in tooth number 25 and area above tooth 24 with a large cavity. Tooth 24 was root treated and tooth 25 was retreated with an over-extension of the gutta percha. The gutta percha was removed completely (in the third x-ray), and replaced with MTA. The tooth was built up with a glass fibre post and composite core and then crowned. Note tooth number 24 apical healing.
MTA can be easily controlled in the apical area without over-extension and an improvement in the crucial apical seal for a successful result.
The case shown below is of a perforation repair with MTA in the furcation position which has been successful since 2008