Mineral trioxide aggregate (MTA) was developed for use as a dental root repair material by
Mahmoud Torabinejad
Mahmoud Torabinejad is an Iranian, a Professor of endodontics, and the Director of the Advanced Specialty Education Program in Endodontics at Loma Linda University School of Dentistry.
Early life and education
Torabinejad was born in Kashan, Ira ...
. It is formulated from commercial
Portland cement
Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in England in the early 19th c ...
, combined with bismuth oxide powder for radio-opacity. MTA is used for creating apical plugs during
apexification Apexification is a method of dental treatment to induce a calcific barrier in a root with incomplete formation or open apex of a tooth with necrotic pulp. Pulpal involvement usually occurs as a consequence of trauma or caries involvement of young ...
, repairing root perforations during
root canal therapy
Root canal treatment (also known as endodontic therapy, endodontic treatment, or root canal therapy) is a treatment sequence for the infected pulp of a tooth which is intended to result in the elimination of infection and the protection of ...
, and treating internal
root resorption
Resorption of the root of the tooth, or root resorption, is the progressive loss of dentin and cementum by the action of odontoclasts. Root resorption is a normal physiological process that occurs in the exfoliation of the primary dentition. Howeve ...
. This can be used for root-end filling material and as
pulp capping
Pulp capping is a technique used in dental restorations to prevent the dental pulp from necrosis, after being exposed, or nearly exposed during a cavity preparation, from a traumatic injury, or by a deep cavity that reaches the center of the toot ...
material. Originally, MTA was dark gray in color, but white versions have been on the market since 2002.
Portland cement
Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in England in the early 19th c ...
is a term applied to a class of materials covering a range of compositions (between silica alumina and calcia). The composition, fineness, setting time and strength of Portland cement are not controlled or guaranteed. Portland cement is an unsuitable substitute for MTA based on several characteristics that are essential to the performance: freedom from heavy metals, dimensional stability and fineness. The FDA requires dental materials to have high purity and be lead and arsenic-free, unlike commercial Portland cement.
Composition
MTA is composed of
tricalcium silicate
Alite is an impure form of tricalcium silicate, , sometimes formulated as ( in cement chemist notation), typically with 3-4% of substituent oxides. It is the major, and characteristic, phase in Portland cement. The name was given by Törnebohm in ...
,
dicalcium silicate
Calcium silicate is the chemical compound Ca2SiO4, also known as calcium orthosilicate and is sometimes formulated as 2CaO·SiO2. It is also referred to by the shortened trade name Cal-Sil or Calsil. It occurs naturally as the mineral larnite.
...
,
tricalcium aluminate
Tricalcium aluminate Ca3Al2O6, often formulated as 3CaO·Al2O3 to highlight the proportions of the oxides from which it is made, is the most basic of the calcium aluminates. It does not occur in nature, but is an important mineral phase in Portl ...
,
tetracalcium aluminoferrite,
calcium sulfate
Calcium sulfate (or calcium sulphate) is the inorganic compound with the formula CaSO4 and related hydrates. In the form of γ-anhydrite (the anhydrous form), it is used as a desiccant. One particular hydrate is better known as plaster of Pari ...
, and
bismuth oxide
Bismuth(III) oxide is perhaps the most industrially important compound of bismuth. It is also a common starting point for bismuth chemistry. It is found naturally as the mineral bismite (monoclinic) and sphaerobismoite (tetragonal, much more rare) ...
. The later 4 phases vary among the commercial products available.
Newly developed fast-set MTAs were developed by
Pozzolan
Pozzolans are a broad class of Silicon_dioxide, siliceous and aluminium oxide, aluminous materials which, in themselves, possess little or no cementitious value but which will, in finely divided form and in the presence of water, react chemically ...
Cement or
Zeolite
Zeolites are microporous, crystalline aluminosilicate materials commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ・y where is either a metal ion or H+. These pos ...
Cement. These were used by
pozzolanic reaction
The pozzolanic activity is a measure for the degree of reaction over time or the reaction rate between a pozzolan and Ca2+ or calcium hydroxide (Ca(OH)2) in the presence of water. The rate of the pozzolanic reaction is dependent on the intrinsic ...
.
Pozzolan
Pozzolans are a broad class of Silicon_dioxide, siliceous and aluminium oxide, aluminous materials which, in themselves, possess little or no cementitious value but which will, in finely divided form and in the presence of water, react chemically ...
Cement is a
mineral aggregate with watery
calcium silicate hydration.
Characteristics and products
#Biocompatible with periradicular tissues
#Non cytotoxic, but antimicrobial to bacteria
#Non-resorbable
#Minimal leakage around the margins.
#Very basic AKA
alkaline
In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a base (chemistry), basic, ionic compound, ionic salt (chemistry), salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as ...
(high pH when mixed with water).
#As a root-end filling material MTA shows less leakage than other root-end filling materials, which means bacterial migration to the apex is diminished.
#Treated area needs to be infection free when applying MTA, because an acidic environment will prevent MTA from setting.
#Compressive strength develops over a period of 28 days, similar to
Portland cement
Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in England in the early 19th c ...
. Strengths of more than 50 MPa are achieved when mixed in a powder-to-liquid ratio of more than 3 to 1.
Originally, MTA products required a few hours for the initial and final setting, which is uncommon in dental materials. Newer materials are available that set more quickly.
MTA Plus is washout resistant.
MTA Products:
Gray: Calcium Alumino-Silicate Cement (C3S, C2S with C3A)- Portland Cement Type I with Bismuth Trioxide. (ex. ProRoot MTA, MTA Angelus)
White : Calcium Carbonate alumino-silicate Cement (CaCO
3 + SiO
2 with Al
2O
3). Final phase is medical grade material similar to Portland Cement. (Limestone Portland Cement) (ex. ProRoot MTA White, MTA Angelus Blanc, EndoCem/Zr, MM MTA, Tech BioSeal MTA, Trioxident, most white MTAs). Bioceramic (ex. OrthoMTA, RetroMTA, Angelus MTA-Fillapex)
GIC solution is
polyacrylic acid
Poly(acrylic acid) (PAA; trade name Carbomer) is a polymer with the formula (CH2-CHCO2H)n. It is a derivative of acrylic acid (CH2=CHCO2H). In addition to the homopolymers, a variety of copolymers and crosslinked polymers, and partially deproto ...
. GIC is
alumino-silicate (glass) bioceramic cement. As MTA is mainly composed of calcium-alumino-silicate, PAA (
polyacrylic acid
Poly(acrylic acid) (PAA; trade name Carbomer) is a polymer with the formula (CH2-CHCO2H)n. It is a derivative of acrylic acid (CH2=CHCO2H). In addition to the homopolymers, a variety of copolymers and crosslinked polymers, and partially deproto ...
) is an accelerant for MTA. PAA set MTA within 15–18 minutes. More aluminate, faster set. Also high concentrated
calcium chloride
Calcium chloride is an inorganic compound, a salt with the chemical formula . It is a white crystalline solid at room temperature, and it is highly soluble in water. It can be created by neutralising hydrochloric acid with calcium hydroxide.
Ca ...
(CaCl
2, 70% more) is well known as accelerator of Portland cement. So high concentrated -over 70%- Calcium Chloride solution sets MTA within 12 minutes. Or
Pozzolanic reaction
The pozzolanic activity is a measure for the degree of reaction over time or the reaction rate between a pozzolan and Ca2+ or calcium hydroxide (Ca(OH)2) in the presence of water. The rate of the pozzolanic reaction is dependent on the intrinsic ...
is also faster set chemical reaction of calcium silicate hydrate. But pozzolanic reacted cement has lower compressive strength at 15 MPa maximum. Easy broken and easily removable property of pozzolanic MTA.
Usage in some clinical cases
Root-end filling after apicectomy
In
root canal therapy
Root canal treatment (also known as endodontic therapy, endodontic treatment, or root canal therapy) is a treatment sequence for the infected pulp of a tooth which is intended to result in the elimination of infection and the protection of ...
where an apical infection is persistent, an apicectomy may be required.
Flap
Flap may refer to:
Arts, entertainment, and media
* ''Flap'' (film), a 1970 American film
* Flap, a boss character in the arcade game ''Gaiapolis''
* Flap, a minor character in the film '' Little Nemo: Adventures in Slumberland''
Biology and he ...
is raised over the tooth and the root tip is resected and a cavity created (3–4 mm) in the root tip remaining. Retrograde application of MTA to the root tip cavity is completed.
MTA was originally developed for root-end filling. There were several different materials such as amalgam, reinforced
zinc oxide eugenol
Zinc oxide eugenol (ZOE) is a material created by the combination of zinc oxide and eugenol contained in oil of cloves. An acid-base reaction takes place with the formation of zinc eugenolate chelate. The reaction is catalysed by water and is acc ...
cements (interim restorative material - IRM), super ethoxy benzonic acid
BA glass ionomer cement
A glass ionomer cement (GIC) is a dental restorative material used in dentistry as a filling material and luting cement, including for orthodontic bracket attachment. Glass-ionomer cements are based on the reaction of silicate glass-powder (calc ...
and
composite resin
Dental composite resins (better referred to as "resin-based composites" or simply "filled resins") are dental cements made of synthetic resins. Synthetic resins evolved as restorative materials since they were insoluble, of good tooth-like appea ...
for root-end filling after apicectomy. MTA, a refined "Portland cement" - calcium alumino-silicate cement-, was found to have less cytotoxic and better results in biocompatibility and micro-leakage sealing ability, giving it more success over root-end filling materials. MTA is not acceptable as "ideal root-end filling material" because MTA has some drawbacks of toxic heavy metal presence, discoloration, difficult handling, short working time, long setting time, washout before setting and washout after set (
calcium carbonate based MTA has solvent of
carbonic acid). The benefits of MTA as a root-end filling material compared to other materials (IRM, Super-EBA, dentine-bonded resin composite, glass ionomer cement,
amalgam
Amalgam most commonly refers to:
* Amalgam (chemistry), mercury alloy
* Amalgam (dentistry), material of silver tooth fillings
** Bonded amalgam, used in dentistry
Amalgam may also refer to:
* Amalgam Comics, a publisher
* Amalgam Digital
...
, RRM) is inconclusive.
For ideal Root-end filling, there are many new materials or improved materials developed.
1.
Glass ionomer cement
A glass ionomer cement (GIC) is a dental restorative material used in dentistry as a filling material and luting cement, including for orthodontic bracket attachment. Glass-ionomer cements are based on the reaction of silicate glass-powder (calc ...
: It is based on alumino-silicate based
bioceramic
Bioceramics and bioglasses are ceramic materials that are biocompatibility, biocompatible. Bioceramics are an important subset of biomaterials.J. F. Shackelford (editor)(1999) ''MSF bioceramics applications of ceramic and glass materials in medicin ...
material. Most cytotoxicity is caused by
polyacrylic acid
Poly(acrylic acid) (PAA; trade name Carbomer) is a polymer with the formula (CH2-CHCO2H)n. It is a derivative of acrylic acid (CH2=CHCO2H). In addition to the homopolymers, a variety of copolymers and crosslinked polymers, and partially deproto ...
. So current GIC as root-end filling material is reducing the cytotoxic acclerator's concentration. - calcium alumino-silicate - MTA (calcium alumino-silicate) + GIC (alumino-silicate), calcium reinforced glass ionomer cement is developed. It's a promising material.
2.
Calcium phosphate
The term calcium phosphate refers to a family of materials and minerals containing calcium ions (Ca2+) together with inorganic phosphate anions. Some so-called calcium phosphates contain oxide and hydroxide as well. Calcium phosphates are white ...
cement (
hydroxyapatite
Hydroxyapatite, also called hydroxylapatite (HA), is a naturally occurring mineral form of calcium apatite with the formula Ca5(PO4)3(OH), but it is usually written Ca10(PO4)6(OH)2 to denote that the crystal unit cell comprises two entities. ...
) bioceramic material: CPC has been studied since 1985 in the US.
Bone grafting
Bone grafting is a surgical procedure that replaces missing bone in order to repair bone fractures that are extremely complex, pose a significant health risk to the patient, or fail to heal properly. Some small or acute fractures can be cured wit ...
material, artificial bioceramic CPC is developed for Root-end filling or pilot material in root-end filling and root repair material.
3.
Calcium silicate
Calcium silicate is the chemical compound Ca2SiO4, also known as calcium orthosilicate and is sometimes formulated as 2CaO·SiO2. It is also referred to by the shortened trade name Cal-Sil or Calsil. It occurs naturally as the mineral larnite.
...
based material - bioceramic material: It was known as bioceramic sealers. But actual bioceramic aggregates are composed of pure medical graded calcium silicate based material.
4.
Calcium aluminate bioceramic material - (alumina cement in minerals,
calcium aluminate cements
Calcium aluminate cements are cements consisting predominantly of hydraulic calcium aluminates. Alternative names are "aluminous cement", "high-alumina cement" and "Ciment fondu" in French. They are used in a number of small-scale, specialized ap ...
in bioceramics)
Alumina is an initial fast setting element and high compressive strength. It has been used as dental products as
luting agent. Calcium aluminate cement (bioceramic) has been developed for dental products and root-end filling material.
These newly developed root-end filling materials are based on
bioceramic
Bioceramics and bioglasses are ceramic materials that are biocompatibility, biocompatible. Bioceramics are an important subset of biomaterials.J. F. Shackelford (editor)(1999) ''MSF bioceramics applications of ceramic and glass materials in medicin ...
, chemically bonded ceramic, not by
mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ( ...
(ceramic in nature) like MTA. Even if mineral shows higher biocompatibility, minerals have potential toxic heavy metals in material.
Bioceramic
Bioceramics and bioglasses are ceramic materials that are biocompatibility, biocompatible. Bioceramics are an important subset of biomaterials.J. F. Shackelford (editor)(1999) ''MSF bioceramics applications of ceramic and glass materials in medicin ...
or
bioMaterial
A biomaterial is a substance that has been engineered to interact with biological systems for a medical purpose, either a therapeutic (treat, augment, repair, or replace a tissue function of the body) or a diagnostic one. As a science, biomateria ...
is used for medical and dental products.
BioMaterials
A biomaterial is a substance that has been engineered to interact with biological systems for a medical purpose, either a therapeutic (treat, augment, repair, or replace a tissue function of the body) or a diagnostic one. As a science, biomateria ...
can reduce the issues on discoloration and toxic heavy metals' presence initially.
Internal and external root resorption, and obturation
In
internal resorption,
root canal therapy
Root canal treatment (also known as endodontic therapy, endodontic treatment, or root canal therapy) is a treatment sequence for the infected pulp of a tooth which is intended to result in the elimination of infection and the protection of ...
is performed, a putty mixture of MTA is inserted in the canal using pluggers to the level of the defect.
Gutta percha
Gutta-percha is a tree of the genus ''Palaquium'' in the family Sapotaceae. The name also refers to the rigid, naturally biologically inert, resilient, electrically nonconductive, thermoplastic latex derived from the tree, particularly from ' ...
and root canal sealer are placed above the defect to complete the root canal treatment. In direct cases, the canal may be completely obturated with MTA.
The MTA will provide structure and strength to the tooth by replacing the resorbed tooth structure. In
external resorption, after
root canal therapy
Root canal treatment (also known as endodontic therapy, endodontic treatment, or root canal therapy) is a treatment sequence for the infected pulp of a tooth which is intended to result in the elimination of infection and the protection of ...
is performed, the
flap
Flap may refer to:
Arts, entertainment, and media
* ''Flap'' (film), a 1970 American film
* Flap, a boss character in the arcade game ''Gaiapolis''
* Flap, a minor character in the film '' Little Nemo: Adventures in Slumberland''
Biology and he ...
is raised over the tooth and the defect removed from the root surface with a round bur. Retrograde application of MTA to the root surface is then completed.
Lateral or furcation perforation
Lateral perforation occurs when an instrument has perforated the root during cleaning & shaping of the canal by the dentist.
If it happens, one should finish cleaning & shaping of the canal, irrigate the canal with
sodium hypochlorite
Sodium hypochlorite (commonly known in a dilute solution as bleach) is an Inorganic chemistry, inorganic chemical compound with the chemical formula, formula NaOCl (or NaClO), comprising a sodium cation () and a hypochlorite anion (or ). It may ...
to
disinfect
A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than ste ...
it and dry it with a paper point.
The perforation can be sealed with a thick mixture of an MTA-type product, preventing bacterial ingress. Make sure that you can locate the canal while the MTA has not set and remove the excess material from the area.
Root canal sealer
Several MTA products are available as sealer. MTA Plus has the highest percentage of MTA in its formula. As calcium based materials have washout property in dam, the antiwashout agents are used. The examples are chitosan and gelatin, which has been used with injectable bone grafting paste. MTA Plus is used with gelatin complex as antiwashout agent. MTA Angelus Fillapex sealer contains less than 20% tri/dicalcium silicate powder in a salicylate carrier medium similar to Sealapex. By element analysis, there is no bismuth oxide of MTA.
EndoSeal MTA, Tech BioSeal MTA are also MTA root canal sealers. MTA is used as filler in the resin like MTA Fillapex. MTA powder is mixed with fillers in the resin. These are not MTA based root canal sealer, but resin modified root canal sealer.
Brasseler Endosequence offers a pre-mixed sealer with a non-reactive carrier medium and the product only sets in vivo. Brasseler's EndoSequence bioceramic sealers are tricalcium silicate-based materials without any calcium aluminate phase. The sealer paste or root repair putty contain a medium of organic liquids. By the diffusion of water into the paste, the materials set in vivo.
Apexification (Necrotic pulp)
When the root is incompletely formed in adolescents and an infection occurs, apexification can be performed to maintain the tooth in position as the roots develop. In case of non-vital pulp: 1. Isolate the tooth with a
rubber dam 2. perform
root canal treatment
Root canal treatment (also known as endodontic therapy, endodontic treatment, or root canal therapy) is a treatment sequence for the infected pulp of a tooth which is intended to result in the elimination of infection and the protection of ...
. 3. Mix MTA and insert it to the apex of the tooth, creating a 3 mm thickness of plug. 5. Fill the canal with sealer and
gutta percha
Gutta-percha is a tree of the genus ''Palaquium'' in the family Sapotaceae. The name also refers to the rigid, naturally biologically inert, resilient, electrically nonconductive, thermoplastic latex derived from the tree, particularly from ' ...
. Alternatively, revascularization techniques are being used where an antibiotic is locally administered. Later a blood clot is formed in the canal and a coronal plug of MTA is placed.
Apexogenesis (Vital pulp)
The process of maintaining pulp vitality during pulpal treatment to allow continued development of the entire root (apical closure occurs approximately 3 years after eruption).
1. Isolate the tooth with a rubber dam 2. Perform a pulpotomy procedure. 3. Place the MTA material over the pulp and close the tooth with temporary cement until the apex is completely formed.
MTA can be used in a one step or a two step approach. It can be used as a powder or a Wet Mix. However a study found that all these approaches have shown to be equally effective.
Pulp capping
In case of mechanical exposure that occurs during cavity preparation and not a pathological exposure due to
caries
Tooth decay, also known as cavities or caries, is the breakdown of teeth due to acids produced by bacteria. The cavities may be a number of different colors from yellow to black. Symptoms may include pain and difficulty with eating. Complicatio ...
.
Proper isolation should be completed using a
rubber dam and cotton pellet.
Disinfection
A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than st ...
of the cavity with
sodium hypochlorite
Sodium hypochlorite (commonly known in a dilute solution as bleach) is an Inorganic chemistry, inorganic chemical compound with the chemical formula, formula NaOCl (or NaClO), comprising a sodium cation () and a hypochlorite anion (or ). It may ...
. then application of MTA over the exposure area. restoration of the cavity with
amalgam
Amalgam most commonly refers to:
* Amalgam (chemistry), mercury alloy
* Amalgam (dentistry), material of silver tooth fillings
** Bonded amalgam, used in dentistry
Amalgam may also refer to:
* Amalgam Comics, a publisher
* Amalgam Digital
...
or composite is done. MTA provides a higher incidence and faster rate of reparative
dentin
Dentin () (American English) or dentine ( or ) (British English) ( la, substantia eburnea) is a calcified tissue of the body and, along with enamel, cementum, and pulp, is one of the four major components of teeth. It is usually covered by ena ...
formation without the pulpal inflammation.
MTA Plus material is also indicated for base and liner in vital pulp therapy.
In root-end filling after apicoectomy, the anti-washout agent (
chitosan
Chitosan is a linear polysaccharide composed of randomly distributed β-(1→4)-linked Glucosamine, D-glucosamine (deacetylated unit) and N-Acetylglucosamine, ''N''-acetyl-D-glucosamine (acetylated unit). It is made by treating the chitin shell ...
or
gelatin
Gelatin or gelatine (from la, gelatus meaning "stiff" or "frozen") is a translucent, colorless, flavorless food ingredient, commonly derived from collagen taken from animal body parts. It is brittle when dry and rubbery when moist. It may also ...
) is useful to prevent from MTA washout. But in vital pulp therapy, anti-washout gel doesn't increase bioactivity or bacterial tight sealing ability of MTA. Instead, hydraulic (100% pure water) MTA shows the higher success rate than anti-washout gel or resin medium. Resin Modified MTA or Calcium Silicate Cement was marketed already. TheraCal LC is
HEMA-free resin modified calcium silicate cement (MTA-like,
Portland cement
Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in England in the early 19th c ...
Type III) light-curable for base and liner in vital pulp therapy.
See also
*
Calcium hydroxide
Calcium hydroxide (traditionally called slaked lime) is an inorganic compound with the chemical formula Ca( OH)2. It is a colorless crystal or white powder and is produced when quicklime (calcium oxide) is mixed or slaked with water. It has m ...
*
Internal resorption
*
External resorption
*
Endodontic therapy
Root canal treatment (also known as endodontic therapy, endodontic treatment, or root canal therapy) is a treatment sequence for the infected pulp of a tooth which is intended to result in the elimination of infection and the protection o ...
References
{{Reflist
Dental materials