About mineral trioxide aggregate

How to Use MTA

To use MTA properly, the clinician must have a basic understanding of the properties of the material as well following the manufacturer's instructions for use.

ProRoot's instructions for use can be found here

For my views on how various clinical procedures can affect the properties of MTA, please go here 

What is mineral trioxide aggregate?

Mineral Trioxide Aggregate (MTA) which is made from combining 80% Portland Cement and 20% Bismuth Oxide, with the percentages calculated by weight as described by the Patent by Torabinejad.1

Three parts MTA powder is mixed with one part distilled water (by weight) as per manufacturer’s instructions. Further information about mixing MTA can be found by going to the  MTA mix website and by referring to the instructions found on the websites of the manufacturers, found here.

Backscatter SEM of ProRoot MTA at 4300 magnification.

What is mineral trioxide aggregate used for?

Mineral trioxide aggregate can be used for endodontic infections and inflammation in humans and can be used for the following procedures: Apicoectomy, Apexification, Pulp capping, Pulpotomies, Pulp regeneration, Internal Repair of Iatrogenic Perforations, Repair of Resorption Perforations.

It should be used by trained dental clinicians (dentists, dental specialists and dental therapists) with a good understanding the procedures and are qualified to perform such procedures.

How does it set?

It is a cement material which, when the powder is mixed with water, sets into a hard filling material. It can be used to fill defects and cavities in teeth. The mixed and set material retains an alkaline pH of 12 which is inherently antibacterial. It is chemically and physically similar to industrial concrete, with the key difference being it is not mixed with sand or stones, which is what differentiates concrete from cement. The 20% bismuth oxide does mildly alter the properties of the Portland cement, however, bismuth oxide is an inert filler and therefore plays little role in the chemical reactions in the setting of Portland cement. The key purpose for the inclusion of bismuth oxide is to achieve radiopacity, that is, to enable clinicians to establish whether a defect is completely restored or whether discrepancies exist.

Why can’t we use Portland Cement for human use?

It doesn’t have bismuth oxide, which is found in MTA.  Therefore it is radiolucent which means clinicians will be unable to determine whether a cavity has been restored or not.

MTA is created with quality assurance.  That is, set procedures to ensure the mix is consistent and reliable.  If you use Portland cement, and mix it with bismuth oxide, what documentation do you have that your mix is both consistent and reliable.  This refers to FDA, CE and TGA marking.  If you create a material for medical human use you should be assessed by the relevant government bodies.  Otherwise you can be accused of experimenting  and using an unsuitable, and assumedly unsafe, material on your patients. 

Videos on how to use MTA

Here is a collection of videoclips on how to use MTA.  The combined playlist will help the clinician who is new to MTA understand how to mix and place MTA in various scenarios.  Prior to using MTA for the first time on a patient, I would recommend seeing the videos first, talking to your friendly endodontist, to ensure your case selection is ideal, and practicing on an extracted tooth using Portland cement.

The video playlists are in order of 

  1. how to handle MTA (eg. how to mix and load instruments) and information about MTA
  2. how to place MTA in extracted teeth - as easy to view demonstrations
  3. how to place MTA intra-orally

How to mix and handle MTA

Ex Vivo (on dummy or extracted teeth) on how to use Mineral Trioxide Aggregate

Clinical Examples on the Usage of Mineral trioxide aggregate


1.Torabinejad J, White DJ. Tooth Filling Material and Method of Use. 1994. WO 94/24955 (PCT). 3. Parirokh M, Torabinejad M. Mineral trioxide aggregate: a comprehensive literature review--Part I: chemical, physical, and antibacterial properties. J Endod;36.