You have a choice when applying a sealer during endodontic treatment such as a root canal. MTA obturation is known to promote a level of osteogenesis and healing not previously possible prior to the availability of MTA (Mineral Trioxide Aggregate).  The following will summarize some of the key components and benefits of MTA obturation. A more detailed clinical treatise is available if you desire to explore the finer points of the procedure.  That said, let’s proceed.
The evolution of MTA and it’s application for MTA obturation
The world of bioceramic based sealers has evolved within the medical and dental industries. You’re accustomed to using sealant materials such as alumina, zirconia, bioactive glass, glass ceramics, hydroxyapatite, and calcium phosphates. 
You’ll also recognize that bioceramic based sealers are typically grouped in two categories: calcium silicate based sealers (MTA based and non-MTA based) and calcium phosphate based sealers. Materials can be considered bioactive or bio-inert. The outcome you achieve depends on their interaction with the surrounding viable tissue.
To date, two formulations of MTA have existed:
The “grey” version: composed of silicate, bismuth oxide, tricalcium aluminate, calcium sulphate, dehydrate (gypsum), and calcium aluminoferrite.
The “white” version: composed of tricalcium silicate, dicalcium silicate, bismuth oxide, tricalcium aluminate, calcium oxide, aluminum oxide, and silicon dioxide.
As a bioactive material, MTA was first introduced as a sealant between roots and the external surfaces of teeth. Its ability to promote healing and osteogenesis makes MTA the leading choice for endodontic therapies.
- Excellent biocompatibility and sealing ability in the presence of moisture
- Hydrophilic nature and good capacity of marginal adaptation
- Good antibacterial properties as result of high pH
- Ability to stimulate cementum-like formation, osteoblastic adherence, and bone regeneration
”Moreover, its sealing, mineralizing, dentinogenic and osteogenic potentials make it the preferred choice for numerous clinical applications such as direct pulp capping, root-end filling, apexogenesis and apexification in immature teeth with necrotic pulp, filling of root canals, treatment of horizontal root fractures, treatment of internal and external resorption, and repair of perforations. 
What outcomes are expected with MTA obturation?
A variety of influences impact outcomes when you use MTA. It’s common to fill endodontic perforations with amalgam, zinc oxide-eugenol cements, calcium hydroxide, and composite resin and glass-ionomer cements.
Beyond materials used, your experience as a practitioner is a factor as well. Treatment can also be negatively impacted by post placement following treatment, the presence of preoperative lesions and their interaction with the perforation site and your patient’s mouth, and your patient’s gender.
More specifically, the perforation’s location and the quality of the final restoration are discovered to have a significant influence on the outcome. At a measurable level, the perforation site (mid-root and apical) and the perforation’s size (larger than 3 mm) provided a major prediction for progressive inflammation to reoccur.
What about the use of MTA obturation for apical surgery?
Your surgical outcomes will be influenced by the materials you use for root-end filling. As you’re aware amalgam has been the most popular material. But an increase in blood mercury levels within one week of the procedure is to be noted.
Also keep in mind that amlagam’s sealing ability can be compromised on occasion when used for apical surgery. This qualifies MTA as a “gold-standard” for endodontic procedures.
- Its excellent sealing ability
- Its hard tissue induction and conduction
You can also expect MTA to provide better regeneration outcomes when applied to periapical tissues. You’ll find the results much better than compared with SuperEBA, amalgam, intermediate restorative material, 4-META/MMA-TBB resin, and thermoplasticized gutta-percha.
Overall, the biocompatibility of MTA gives it the advantage for filling the apex in large root canals. And you’ll experience the same advantages with apexification/apexiogenesis in immature teeth that contain necrotic pulp.
Are there any disadvantages associated with MTA obturation?
The problem of discoloration
The potential for discoloration as the main disadvantage during vital pulp therapy and perforation repair has prompted some alternatives. One option you have is using bioactive cements in similar procedures. You’ll discover that this alternative can reduce the setting time.
Even so, be aware that discoloration can occur when alternatives to MTA are used. This is primarily due to contact with sodium hypochlorite and other formulations containing tricalcium silicate, dicalcium silicate, tricalcium aluminate, calcium oxide, and tungstate as an opacifier.
There is a solution to discoloration. The use of PDTM MTA White (Produits Dentaires) has produced no staining or discoloration. And it accomplished this without changing the biological or chemical features of MTA.
The problem of bleeding management
You’ll discover that blood contamination could be a factor that increases discoloration in calcium silicate-based materials. Bismuth oxide-free Portland cement can also reveal diminished color when bleeding is present.
Unset MTA and its surface porosity is what commonly leads to the presence of blood elements. This could explain the discoloration associated with calcium-silicate based cements. Even more specific is understanding that erythrocyte can penetrate the material and following hemolysis the cement and tooth can reveal discoloration.
What protocols can help assure success with MTA obturation?
Following detailed manufacturer instructions can lead to problem-free usage of MTA. Carrier specific recommendations are necessary for MTA obturation.
Dedicated carriers are available for your use. Keep in mind that size differentials determine the amount of material placed into the root canal.
Carriers should allow fast, efficient, and precise positioning of the material. MAP System (Produits Dentaires) is one such dedicated carrier that adapts to every clinical situation. It accommodates needles of differing sizes, angles, and materials:
- The MAP System advantage involves NiTi Needles
- Useful in both orthograde and surgical procédures
- They can be bent to allow precise material placement
- Shape of the needle is retained after sterilization
Overall, when using an MTA carrier it’s mandatory to avoid allowing the material to harden inside of the applicator. Once hardening occurs it’s next to impossible to remove.
Instrument efficiency can be maintained with proper cleaning of the needle immediately after MTA extrusion. Clinical procedures should determine the amount of MTA used.
Generally speaking, it’s not necessary to completely fill the root canal with MTA. Once it’s set, material removal would be more difficult. Follow accurate protocols and use specifically designed tools. This will lead to good outcomes when using MTA obturation for primary and secondary endodontic treatments.
This article was based on the paper “Clinical applications of mineral trioxide aggregate in endodontics” by dr Arnaldo Castellucci. The original document (in English) is available on our e-Learning platfom.
 Torabinejad M, Parirokh M. Mineral trioxide aggregate: a comprehensive literature review–part II: leakage and biocompatibility investigations. J Endod. 2010;36(2):190-202.
 Clinical applications of MTA in endodontics Arnaldo Castellucci, Matteo Papaleoni, Francesca Cerutti
 Jafari F, Jafari S. Composition and physicochemical properties of calcium silicate based sealers: A review article. Journal of clinical and experimental dentistry. 2017;9(10):e1249-55
 Parirokh M, Torabinejad M, Dummer PMH. Mineral trioxide aggregate and other bioactive endodontic cements: an updated overview – part I: vital pulp therapy. Int Endod J. 2017
 Clinical applications of MTA in endodontics, Arnaldo Castellucci, Matteo Papaleoni, Francesca Cerutti