The use of mineral trioxide aggregate in endodontics.
Mineral trioxide aggregate (MTA), composed mainly of tricalcic silicate, tricalcic alluminate, bismuth oxide, is a particular endodontic cement. It is made of hydrophilic fine particles that harden in the presence of dampness or blood. It is biocompatible, radiopaque and it is harder to infiltrate, compared to classic materials for root filling such as amalgam, cements, Super-EBA, and IRM. and SEM studies of sections and copies in resin of root neoapices filled with amalgam, IRM, Super-EBA and MTA, as well as tests of microinfiltration have shown that MTA has excellent sealing capacities. It requires a working time of about 5 min and a hardening time that varies from 2 h and 45 min to 4 h according to the density of the air entrapped during mixing and the dampness of the receiving site. The long hardening time reduces internal tensions and the incidence of marginal infiltration, but it forces to definitively fill the tooth in the following sitting, with an interval of at least 3 days from the MTA application. Clinical experience shows how MTA is a material of choice in cases not only of endodontic surgery, apicectomy and retrograde filling but also in the sealing filling of perforations of the pulp chamber and of the root, stripping, internal reabsorptions, readaptations, lacerations, and apical transports. It has been used with success also in direct cappings and in apexifications instead of calcium hydroxide, leading to quicker therapies and more predictable


RESULTS
The authors outline the operative phases of the different treatments proposed, make a survey of the most important studies published so far and hope that a new sealing cement with more reduced hardening times will soon be available.
Casella
G
G
Conservative Dentistry Unit, Department of Surgical and Medical Specialties, University of Catania, Catania, Italy. giuseppinacasella@virgilio.it
Ferlito
S
S
D017607:Aluminum Compounds / Q000009:adverse effects / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D001672:Biocompatible Materials / Q000009:adverse effects / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D017610:Calcium Compounds / Q000009:adverse effects / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003723:Dental Amalgam / Q000494:pharmacology; D003738:Dental Cements / Q000009:adverse effects / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D003763:Dental Leakage / Q000517:prevention & control; D003785:Dental Pulp Capping / Q000379:methods; D004338:Drug Combinations; D006801:Humans; D022125:Lacerations / Q000628:therapy; D008963:Molar / Q000187:drug effects; D010087:Oxides / Q000009:adverse effects / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D010483:Periapical Diseases / Q000628:therapy; D010895:Pit and Fissure Sealants; D012390:Root Canal Therapy / Q000379:methods; D017640:Silicates / Q000009:adverse effects / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D013997:Time Factors; D014092:Tooth Root / Q000293:injuries / Q000601:surgery
D017607:Aluminum Compounds; D001672:Biocompatible Materials; D017610:Calcium Compounds; D003738:Dental Cements; D004338:Drug Combinations; D010087:Oxides; D010895:Pit and Fissure Sealants; D017640:Silicates; C086631:mineral trioxide aggregate; D003723:Dental Amalgam