Background and Aim: In 1993, MINERAL TRIOXIDE AGGREGATEs ((MTA)), a grey-colored material was introduced to dentistry. A similar product in white-color was also produced later. The aim of this study was to review the literature in order to compare the chemical composition of these two different types of (MTA).Materials and Methods: Over 600 articles have been published about the properties of (MTA), 33 of which were about chemical and 28 were on its physical properties. In addition, about 80 articles have been published on similarities and differences between (MTA) and Portland Cements (PC). This article reviews the history of (MTA)’s manufacturing, its introduction to market, its patent, its commercial brands, and its similarities with PC. We also reviewed size of powder particle, setting form, and also hydration reaction of (MTA).Results: Mainly consisting of CaO and SiO2, (MTA)s and PC have similar compositions. (MTA) also contains Bi2O3 as an opacifier. The main difference in chemical composition of white (MTA) and PC with grey (MTA) is that the latter contains less amount of some minor elements specifically FeO. White (MTA) has finer particles and crystals compared to the grey one. No phosphate does exist in (MTA) composition, but during the hydration, this material is able to release calcium and hydroxyl ions which, in reaction to exogenous phosphate, results in hydroxyapatite formation.Conclusion: Both (MTA) and PC are hydrophilic cements. Regarding the biocompatibility of these materials, (MTA) is considered suitable for clinical applications; while no permission exists for clinical use of PC.

Introduction: Root perforation is an endodontic procedural error. Treatmentof perforation depends on the location and size of perforation, duration of exposure to the oral cavity, patient's cooperation and degree oftissue inflammation. Several materials have been introduced to seal off the perforation. (MTA) is one of the best materials for this purpose.Case Report: We report the repair of distal root perforation in a primary mandibular second molar of a 9 year-old boy who had congenital absence of the second premolar tooth at the same quadrant. The perforation site was sealed with (MTA) and the three root canals were filled with gutta percha. Follow up visits at 1, 3, 6, 12, 21 and 24 months showed clinical and radiographic success of treatment.

BACKGROUND AND OBJECTIVE: One of the main aims of root canal therapy is to seal the canal. The aim of the retrograde filling in apical resection operation is to obtain an effective apical sealing. Various materials have been recommended for retrograde fillings. For evaluation these materials the most important characteristics is their sealing ability. The aim of this study was to evaluate the amount of dye penetration in two common retrofill materials (amalgam and (MTA)) and compare them with hydroxy apatite in root end surgeries. METHODS: In this invitro study 69 single root extracted human teeth were used and after instrumentation, they were obturated with lateral condensation. 3 mm of the apical root was resected, and root-end cavities were prepared. Then the teeth were randomly divided into three groups of 20 specimens (white (MTA), amalgam and hydroxy apatite). The amount of micro leakage in each group was evaluated by using dye penetration technique. Dye penetration at the rate of 0-0.99mm was considered little, 1-1.99mm moderate, 2-2.99mm severe and 3mm or more extensive. Groups were evaluated and compared.FINDINGS: Mean microleakage in the moderate, severe and extensive group for amalgam were 0%, 35% and 65%, (MTA) 10%, 15% and 75% and hydroxy apatite were 5%, 35% and 50% respectively. There was not significant relationship between the three materials ((MTA), hydroxy apatite and amalgam) and the amount of dye penetration.CONCLUSION: The results showed that hydroxy apatite can be used as a retrofill material and it has no significant difference with amalgam and (MTA).

Background and Objectives: One of the common matrials as a root-end filling is MINERAL TRIOXIDE AGGREGATE that has different usages in Endodontics. The purpose of this study was to compare the microleakage of gray and White (MTA) as a root.end filling material.Materials and Methods: 50 single-rooted teeth were divided into two experimental groups of 20 teeth each and two positive and negative control groups of 5.After cleaning, shaping, obturation an cutting away of 3 millimeter from the apex, 3 mm deep preparations were made. The root-end preparation of experimental groups were filled with white (MTA) and gray (MTA). In positive and negative control groups no material was placed. Leakage was determined using a dye penetration method. Leakage was observed with a stereomicroscope at 16 magnifications. Accuracy of 0.1 mm was used for measurements. Data was analyzed using the ANOVA test at the 0.05 level of significance. Results: Amount of leakage was zero and 3 mm in negative and positive control groups, respectively .The mean leakage was 0.5 mm in the white (MTA) and 0.3 mm in the gray (MTA). There was not any significant difference between two experimental groups (P=0.14). Conclusion: There was not any difference between apical leakage when we used white and gray (MTA) as a root-end filling material in this in vitro study.

Introduction: Root MINERAL TRIOXIDE AGGREGATE ((MTA)) is a type of (MTA) that has been introduced in the Iranian market. There have been few studies on this substance. This study compared the push-out bond strength of Root (MTA) and CEM cement, which were both Iranian products. Materials & Methods: This in vitro study was performed on 20 extracted maxillary incisors. Samples were divided in two groups. The canals of the first group were filled with Root (MTA) and the second group by CEM cement. In order to investigate the push-out bond strength, the device applied a force in the direction parallel to the longitudinal axis of the sample so that the desired materials would fail. Each sample was classified into one of three types of failureincluding adhesive (failure in the material and dentin interface), cohesive (failure in the material itself) or a combination of both. Results: There was no significant difference between the mean pressure on teeth for the two groups (P>0. 05). There was no significant difference between the frequencies of different types of failure between the two groups (P>0. 05). Cohesive failure in the CEM group was twice as high as in the (MTA) group (P>0. 05). Conclusion: There was not any significant difference between the push-out bond strength of CEM cement and Root (MTA) cement. These findings demonstrated that Root (MTA) material showed a satisfactory result in the bond strength test compared to CEM material, and could be used as an alternative to CEM cement.

Background and Aim: MINERAL TRIOXIDE AGGREGATE ((MTA)) usually produces moisture by paper cone for at least 4 hours with regard to some studies that the moisture of periapical tissues is enough to set the (MTA). The aim of this study was comparison of one-visit apexification with two-visit apexification using (MTA) plug.Materials & Methods: In this experimental study 70 extracted single-rooted human teeth were selected. The crowns and 2mm of apices were cut. Canal preparation was performed to ISO size No.1 00 in the apical portion. The teeth were randomly divided into 2 experimental groups of 25 and 2 control groups of 10 teeth. The canals in group one were obturated immediately after (MTA) plug placed. In group two after placing (MTA) plug, a moist paper point was placed inside the canal, and after 24 hours, canals were obturated. The roots were covered with two layers of nail polish in the designed system and were transferred in a sterile BHI (Brain Heart Broth) culture. A fresh solution of Enterococcus faecalis was injected to the system every 3 days. For 90 days, the time of culture contamination was registered. Survival analysis with Kaplan-Meier method & Log Rank test were used to analyze the data.Results: Mean and 95% CI of survival time in one visit group was 12.77 (0-25.69) days and in two visit group was 4.16 (1.3-7.01) days. There was no significant difference in survival curve between the two groups.Conclusion: Results showed that apexification in one visit by placing an apical plug of (MTA) is a predictable and reproducible clinical procedure.

Background and Aim: One of the materials used for repairing root-end fillings is MINERAL TRIOXIDE AGGREGATE ((MTA)).(MTA) has been reported to remain soft when placed in perforations with a high degree of inflammation. The purpose of this study was to evaluate the effect of environmental pH on the setting and micro structure of (MTA).Materials and Methods: In this interventional study, tooth-colored (MTA) (Pro Root, Dentsply, USA) was mixed according to the manufacture's instructions. The mixture was placed into cylindrical polycarbonate tubes. The specimens were randomly divided in to four groups of 9 and were subjected to a pressure of 3.22 MPa~ 6kg applied for 1 minute in a custom-made condenser device. Each of the 9 specimens were then stored at room temperature and saturated humidity in four plastic plates containing buffer solutions of butyric and propyonic acid with a pH of 4.4, 5.4, 6.4 and 7.4, for 4 days. The Vickers hardness test was performed on each specimen. The microstructures of the specimens were analyzed using a scanning electron microscope after sectioning the specimens with a scalpel. Data were subjected to one-way ANOVA.Results: The lowest and highest PH values were 4.4 and 7.4, respectively. A statistically significant difference was observed between all four groups (p<0.05). Unrelated (MTA) particles scattered in a non uniform matrix were seen in specimens stored in pH 4.4 solutions whereas cases kept in a pH 7.4 environments had distinctive crystalline structures embedded in a more uniform matrix.Conclusion: The results indicate that the acidic pH of inflamed tissues can adversely affect the setting of (MTA).