Set Mineral Trioxide Aggregate Research Articles

Biocompatibility and pro-mineralization effect of tristrontium aluminate cement for endodontic use

Background/purposeTristrontium aluminate (S3A) is a hydraulic cement with setting behavior similar to that of mineral trioxide aggregate (MTA). This study examined the biological effects of S3A on mouse dental papilla cells (MDPs) in vitro and on rat exposed pulps in vivo. Materials and methodsExtracts of S3A and MTA were prepared by immersing each cement in ultrapure water. MDPs were cultured with S3A or MTA extracts, and cell proliferation was evaluated with a tetrazolium-salt assay. Attachment of MDPs on the set cements was examined with scanning electron microscopy (SEM). mRNA expression of bone morphogenic protein (Bmp2), osteocalcin (Oc) and osteopontin (Opn) in MDPs exposed to S3A or MTA extracts was determined with reverse transcription-quantitative polymerase chain reaction. Mineralized nodule formation was evaluated with Alizarin Red S staining. Simulated body fluid (SBF)-dipped S3A was examined with SEM and energy dispersive X-ray analysis (EDX). Exposed molar pulps of male Wistar rats capped with S3A or MTA were histologically examined. ResultsS3A extract did not inhibit proliferation of MDPs. Set S3A and MTA exhibited attachment of MDPs on their surface. S3A extract showed significantly higher mineralized nodule formation and mRNA expression of Bmp2, Oc, and Opn than did MTA extract. SBF-dipped S3A exhibited formation of surface precipitates, which were composed of Ca, P, Sr, and Al. Direct pulp capping with S3A and with MTA induced mineralized tissue repair of the exposed pulp. ConclusionS3A possesses biocompatibility and pro-mineralization effects comparable to those of MTA.

The biocompatibility and mineralization potential of mineral trioxide aggregate containing calcium fluoride–An in vitro study

Background/purposeMTA is used to induce hard tissue regeneration in various procedures. This study evaluated the biocompatibility and mineralization potential of mineral trioxide aggregate (MTA) containing calcium fluoride (CaF2). To verify if the change of components affected physical properties, the setting time, solubility, and surface roughness were measured. Materials and methodsHuman dental pulp cells (HDPCs) were treated with powder and set MTA containing CaF2 (0, 1, 5, and 10 wt %). The proliferation of HDPCs was investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The mineralization potential of HDPCs was investigated with the relative gene expression of alkaline phosphatase (ALP), collagen type I (ColI), osteocalcin (OCN), and runt-related transcription factor 2 (Runx2) using real-time reverse transcription polymerase chain reaction (RT-PCR). For investigating the physical properties, setting time and solubility were tested. Surface profiles of material were analyzed by a non-contact surface profiler and a scanning electron microscope (SEM). ResultsMTA-5% CaF2 mixtures increased the proliferation and the mineralization-related gene expression of HDPCs to a greater degree than pure MTA. The addition of CaF2 to MTA delayed the setting, but the difference was only significant in the MTA-10% CaF2. Solubility and surface roughness was not altered. ConclusionThe addition of more than 5% CaF2 can be considered to increase the regeneration potential of pulp cells without adverse effects on physical property.

The influence of particle size and multi-walled carbon nanotube on physical properties of mineral trioxide aggregate

The objectives of this study are to reduce the particle size distribution of Mineral Trioxide Aggregate (MTA) and to investigate its impact on setting time, radiopacity, flexural and compressive strength. Furthermore, the effect of adding multi-walled carbon nanotube to MTA composite was studied. MTA particles sizes were decreased using Wet-Stirred-Media-Milling (time intervals of 5, 10, 15 and 20 h). The distilled water and multi-walled carbon nanotube (0.25%, 0.5%, 0.75% and 1 wt%) were mixed and added to the MTA for hydration. MTA setting time, flexural and compressive strength and radiopacitiy were measured. Moreover, the unset MTA was analysed using x-ray-diffraction and the surface of the set MTA was observed by scanning electron microscopy. Tukey’s HSD test shows that initial and final setting times were decreased significantly up to 15 h of milling (p < 0.05). Flexural/Compressive strength of MTA were significantly decreased after milling for 10 and 20 h (p < 0.05). The flexural strength and compressive strength of the specimens reinforced with MCNTs show an increase of 76% and 10.2%, over plain MTA specimens. The results suggest that MTA setting-time can be accelerated and regulated by reducing particle size distribution without adding chemicals. The mechanical properties of MTA were significantly improved with the addition of multi-walled carbon nanotube without negative impact on setting time. In this study, a Nano Fast Cement composite with short setting time and high strength was developed by modification of MTA material.

Cytotoxicity of two available mineral trioxide aggregate cements and a new formulation on human gingival fibroblasts.

Aim:The purpose of this study was to investigate the cytotoxicity of nanohybrid mineral trioxide aggregate (MTA) in comparison with calcium-enriched mixture (CEM) cement and MTA-Angelus, using human gingival fibroblasts (HGFs).Materials and Methods:Nine disc-shaped specimens of each material (in 2 set stat: A, set for 24 h; B, set for 30 min; and C, fresh stat) were prepared. HGFs were exposed to tested materials’ extracts or control media. Cytotoxicity testing was performed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay in two time intervals.Statistical Analysis:Results were evaluated by one-way ANOVA and t-test. Statistical significance was set at P < 0.05.Results:CEM cement demonstrated favorable cell viability values when completely set (24 h set MTA = 24 h set CEM) at both time intervals. Interestingly, 24 h after incubation, CEM in Groups B and C demonstrated higher cell viability values than MTA (P < 0.05). However, after 72 h of incubation, these groups of CEM and MTA showed equal cell viability. All samples of nanohybrid MTA had slight cytotoxic effects after 24 h of incubation, and moderate cytotoxic effects after 72 h of incubation.Conclusion:Set CEM and set MTA-Angelus exerted similar, favorable effects on cell viability. However, within the limitations of this in vitro study, the results suggest that nanohybrid MTA could not be recommended as a material of choice for cervical root resorption.

Cytotoxicity of Various Endodontic Materials on Stem Cells of Human Apical Papilla.

Introduction: This in vitro study assessed and compared the cytotoxicity of mineral trioxide aggregate (MTA), calcium-enriched mixture (CEM) cement, Biodentine (BD) and octacalcium phosphate (OCP) on stem cells of the human apical papilla (SCAP). Methods and Materials:SCAPs were isolated from two semi-impacted third molars. The cells were cultured in wells of an insert 24-well plate and were then incubated. The plates were then removed from the incubator and randomly divided into four experimental groups that were exposed to 1-mm discs of set MTA, CEM, BD or OCP, and one untreated control group. After 24, 48 and 168 h, the plates were removed from the incubator and 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide (MTT) solution was added to each well. Data were analyzed at different time points using the repeated measures ANOVA followed by Bonferroni test and the level of significance was set at 0.05. Results:Cytotoxicity of the four materials was not significantly different from that of the control group at 24, 48 and 168 h (P>0.05). Two-by-two comparison revealed that cytotoxicity of MTA and CEM cement was significantly different from each other at 168 h (P<0.05) although the cytotoxicity of CEM was less than MTA. Cytotoxicity of OCP and MTA was also significantly different from each other at 48 h and OCP had more favorable biocompatibility than MTA (P<0.05). Conclusion:CEM, OCP, BD and MTA showed acceptable biocompatibility when exposed to SCAP. Over time, CEM showed the least cytotoxicity among the materials under study.

Effect of acidic solutions on the microhardness of dentin and set OrthoMTA and their cytotoxicity on murine macrophage.

ObjectivesTo evaluate the effects of three acids on the microhardness of set mineral trioxide aggregate (MTA) and root dentin, and cytotoxicity on murine macrophage.Materials and MethodsOrthoMTA (BioMTA) was mixed and packed into the human root dentin blocks of 1.5 mm diameter and 5 mm height. Four groups, each of ten roots, were exposed to 10% citric acid (CA), 5% glycolic acid (GA), 17% ethylenediaminetetraacetic acid (EDTA), and saline for five minutes after setting of the OrthoMTA. Vickers surface microhardness of set MTA and dentin was measured before and after exposure to solutions, and compared between groups using one-way ANOVA with Tukey test. The microhardness value of each group was analyzed using student t test. Acid-treated OrthoMTA and dentin was examined by scanning electron microscope (SEM). Cell viability of tested solutions was assessed using WST-8 assay and murine macrophage.ResultsThree test solutions reduced microhardness of dentin. 17% EDTA demonstrated severe dentinal erosion, significantly reduced the dentinal microhardness compared to 10% CA (p = 0.034) or 5% GA (p = 0.006). 10% CA or 5% GA significantly reduced the surface microhardness of set MTA compared to 17% EDTA and saline (p < 0.001). Acid-treated OrthoMTA demonstrated microporous structure with destruction of globular crystal. EDTA exhibited significantly more cellular toxicity than the other acidic solutions at diluted concentrations (0.2, 0.5, 1.0%).ConclusionsTested acidic solutions reduced microhardness of root dentin. Five minute's application of 10% CA and 5% GA significantly reduced the microhardness of set OrthoMTA with lower cellular cytotoxicity compared to 17% EDTA.

Effect of post space preparation on the sealing ability of mineral trioxide aggregate and Gutta-percha: A bacterial leakage study.

Aim:The purpose of this study was to evaluate the effect of post space preparation on the sealing ability of teeth obturated with mineral trioxide aggregate (MTA) and Gutta-percha.Materials and Methods:Fifty intact human mandibular premolars, after decoronation and biomechanical preparation, were randomly divided into three experimental groups. In Group A (n = 10), the canals were obturated with Gutta-percha using cold lateral compaction technique, followed by immediate post space preparation. In Group B (n = 10), the canals were obturated with 8 mm of MTA and in Group C (n = 10), sectional obturation with 4 mm of MTA was done, followed by delayed post space preparation. All specimens were subjected to bacterial leakage analysis, and the occurrence of turbidity was checked.Results:All specimens in the lateral compaction group leaked. The mean number of days at which leakage was observed in Groups A, B and C were 18.5 days, 93.6 days and 95.5 days.Conclusions:MTA can be considered as an alternative to Gutta-percha as an apical third restorative material for teeth indicated for post and core, as it demonstrates better-sealing ability compared with Gutta-percha. Further, the removal of set MTA for post space preparation does not disrupt the integrity of the remaining apical MTA.

In Vitro Cytotoxicity of GuttaFlow 2 on Human Gingival Fibroblasts

IntroductionThe primary aim of this study was to evaluate the cytotoxic effects of GuttaFlow 2 (Coltène Whaledent, GmBH+Co KG, Langenau, Switzerland) on human gingival fibroblasts (HGFs). MethodsSamples of the test materials GuttaFlow 2, mineral trioxide aggregate (MTA), AH Plus (Dentsply DeTrey, Konstanz, Germany), and RealSeal sealer (SybronEndo, Orange, CA) were fabricated in cylindrical nonreactive plastic tubes of 3-mm diameter and 2-mm height. Extracts of freshly mixed and set samples were prepared using the ratio of 0.5 cm2/mL, 1 cm2/mL, and 1.5 cm2/mL according to ISO 10993 series. The extracts were incubated with HGF cells for 24 and 72 hours. A cell counting kit-8 assay (Dojindo, Kumamoto, Japan) assay was used to examine cytotoxicity. The results were analyzed with the independent t test and 1-way analysis of variance test (P < .05). ResultsAt all experimental conditions, the extracts of freshly mixed GuttaFlow 2 were nontoxic, whereas the extracts of freshly mixed and set AH Plus and RealSeal sealers were toxic to HGF cells (P < .05). The extracts of set GuttaFlow 2 were toxic at 72 hours (P < .05) and nontoxic at 24 hours. The extracts of freshly mixed MTA were nontoxic at both time points. For the extracts of set MTA, 1.5 cm2/mL was toxic at 72 hours and 1.5 cm2/mL and 1 cm2/mL were toxic at 24 hours (P < .05). ConclusionsBoth GuttaFlow 2 and MTA evoked a less toxic response to HGF cells than AH Plus and RealSeal sealer.

Calcium Enriched Mixture and Mineral Trioxide Aggregate Activities against Enterococcus Faecalis in Presence of Dentin.

The purpose of this in vitro study was to compare the antibacterial activity of Calcium Enriched Mixture (CEM) with ProRoot Mineral Trioxide Aggregate (MTA) against Enterococcus faecalis (E. faecalis) in the presence/absence of dentin powder. Two series of freshly mixed (10, 50, and 100 mg), set crushed powder (10, 50, and 100 mg), and pieces of uncrushed set (50, 100 mg) of CEM and MTA were prepared (n = 32 groups). All samples were suspended in normal saline for direct exposure test against E. faecalis; in the second series, 50 mg of the dentin powder was also added to the solution. Dentin powder suspension and bacterial suspension served as negative and positive control groups, respectively (n = 2). The suspensions were incubated at room temperature for 1, 60, and 240 min; each group was tested five times and survival of the bacteria in test solutions was assessed by 10-fold serial dilutions and cultured on Brain Heart Infusion (BHI) plates. The plates were incubated at 37ºC. The mean values of log10 CFU were calculated and compared in all tested groups. The total number of tests added up to 510 times. In presence of dentin powder, freshly mixed powder from set materials, and pieces of uncrushed set materials of both tested cements killed > 95% of the bacterial cell in 1 min. Adding dentin powder caused an increase in antibacterial activity of freshly mixed powder from crushed set CEM and MTA but no acceleration in bacterial killing was observed, when dentin was mixed with set or uncrushed cements. Dentin powder alone reduced the number of viable bacteria in the 4-hour duration. There were no significant differences between different weights of freshly mixed, crushed set powder and uncrushed set of CEM cement and MTA at different times. Under the conditions of this in vitro study, CEM cement as well as MTA have antibacterial effects against E. faecalis. The addition of equal amounts of dentin powder to the suspension of CEM or MTA resulted in swifter elimination of bacteria.

Unintentional extrusion of mineral trioxide aggregate: a report of three cases

Mineral trioxide aggregate (MTA) is the material of choice for apical barrier techniques during root canal treatment of teeth with open apices. However, the precise control of MTA during the placement of an apical plug is challenging. This article describes the outcomes of unintentional extrusion of MTA into the periradicular tissue during apical barrier treatment in three cases. Three cases of maxillary central incisors in adult patients with open apices were referred for treatment. After conventional access and canal preparation, MTA was placed into the apical portion of the root canals to act as an apical barrier/plug. A large increment of MTA was extruded in all cases. In Case 1, after a 4-year follow-up, the extruded MTA had resorbed and the periradicular lesion had healed. In Cases 2 and 3, after follow-up, the patients remained symptomatic and were scheduled for periradicular surgery. In Case 2, soft unset particles of MTA were present in the lesion and were curetted. In Case 3, the extruded MTA had set hard but was sandwiched between the oral mucosa and bone; its removal relieved the pain experienced on buccal palpation. Extruded MTA may not harden and may be associated with ongoing periapical irritation; Extruded set MTA when encapsulated in the mucosa and not surrounded by bony matrix may act as a mechanical irritant on palpation; Mineral trioxide aggregate should be confined to the root canal system; Teeth where MTA has been extruded beyond the foramen should be followed-up to monitor the outcome.

English

In the case of limited access in endodontic surgery, an alternative approach includes obturation of the canal with mineral trioxide aggregate (MTA) prior to surgery. Following the setting of MTA, endodontic surgery is carried out by resecting the root-end and exposing the set MTA without cavity preparation. This may also be performed with other retrofilling materials. This study was designed to compare the sealing ability of resected resilon, MTA and gutta-percha. 84 maxillary anterior teeth were instrumented and randomly assigned into three experimental groups (n = 20), each having a positive and negative control (n = 4). The canals were filled with resilon, MTA or gutta-percha. Following the root-end resection and submergence in India ink, the maximum dye penetration was measured. Welch and Brown-Forsythe test was used to analyze the data. The resected gutta-percha showed significantly more leakage than MTA (p = 0.041). The leakage in resected resilon was more than MTA and slightly lesser than gutta-percha. However, the differences were not statistically significant (p > 0.05). Based on this study, MTA is the most appropriate choice in this approach.

Effects of Root Canal Irrigants on the Push-out Strength and Hydration Behavior of Accelerated Mineral Trioxide Aggregate in its Early Setting Phase

Introduction The purpose of this study was to evaluate the effects of endodontic irrigants on the push-out strength and hydration behavior of accelerated mineral trioxide aggregate (MTA) in its early setting phase. Methods In an in vitro perforation model, MTA with or without 10% CaCl 2 was condensed and allowed to initial set for 10 minutes. The samples were divided into four groups ( n = 10) to be immersed into either 3.5% sodium hypochlorite (NaOCl) or 2% chlorhexidine gluconate (CHX) for 30 minutes and then allowed to set for 48 hours. In the control group, a wet cotton pellet was placed over MTA. The maximum force applied to the set MTA mixture before dislodgement was recorded. Irrigant-treated surfaces were examined using a scanning electron microscope (SEM). Chemical elements of these surfaces were also analyzed by energy dispersive x-ray spectroscope (EDS). Results The push-out strength of group A1 (NaOCl-treated accelerated MTA) was the highest of all groups. When compared with nonaccelerated MTA, CaCl 2-accelerated MTA showed significantly higher push-out strength ( p < 0.05). NaOCl-treated groups showed significantly higher push-out strength than CHX-treated groups ( p < 0.05). Scanning electron microscopic examination and EDS analysis showed that the formation of calcium hydroxide crystals on accelerated MTA exposed to NaOCl was increased compared with those of the control group. Conclusion These findings imply that the use of accelerated MTA under the NaOCl irrigation was effective in perforation repair without altering its hydration behavior even in the early setting phase.

The effect of post space preparation in teeth obturated with Mineral Trioxide Aggregate evaluated using a fluid filtration system

The aim of this study was to evaluate the seal of a 4-mm Mineral Trioxide Aggregate (MTA) filling after post space preparation. Forty single-rooted premolar teeth without curved root anatomy and fractures were selected. The root length was standardized to 12 mm by removing excess from the apical end. The roots were instrumented to a 50 K-file by the step-back technique. The roots were randomly divided into groups A and B, of fifteen each. In group A, the canals were obturated with 7 mm of white MTA. After 24 h, 3 mm of MTA was removed to simulate post space preparation using a long shank diamond round bur. In group B, the canals were filled with 4 mm of white MTA. All samples were attached to a fluid filtration device. Measurements (µl min⁻¹ cm H₂O⁻¹) were taken every 2 min, for 10 min and data were analyzed by an independent t-test (P > 0.05). Fluid transport averaged in groups A and B at 9.2 × 10⁻⁴, and 11.8 × 10⁻⁴ µl min⁻¹ cm H₂O⁻¹, respectively. Independent t-test showed no significant difference between the groups (P < 0.05). Removing set MTA using a round bur for post space preparation does not affect its sealing ability, when 4 mm of MTA remains.

An In Vitro Study to Assess the Setting and Surface Crazing of Conventional Glass Ionomer Cement when Layered over Partially Set Mineral Trioxide Aggregate

The aim of our study was to assess the setting time and surface crazing of glass ionomer cement when layered over partially set mineral trioxide aggregate (MTA). To assess setting time, 40 hollow, cylindrical stainless steel molds were taken and equally divided into 4 groups. In groups I, II, and III glass ionomer cement was layered over partially setting MTA at 45 minutes, 4 hours, and 3 days, respectively. Group IV was used as a control. An additional 50 specimens were prepared for assessment of surface crazing. Twenty specimens (groups I and II) were prepared to study normal and desiccated patterns of conventional glass ionomer cement, respectively. Thirty specimens (groups III, IV, and V) were prepared by layering glass ionomer cement over partially set MTA at various time intervals. All the specimens were stained with red ink and analyzed for craze lines by light microscopy. From our study, it was observed that there was no statistical difference in setting time of glass ionomer cement when layered over partially set MTA in comparison to that of the control group. No craze lines were observed in those specimens (groups III, IV, and V) when viewed under staining and light microscopy. It could be concluded that conventional glass ionomer cement might be layered over partially set MTA after 45 minutes and could be used for single visit procedures.

Analysis of Mineral Trioxide Aggregate Surface when Set in the Presence of Fetal Bovine Serum

Understanding the chemical and physical characteristics of set mineral trioxide aggregate (MTA) surface can provide insight into its bioactivity. The purpose of this study was to describe the surface chemistry and morphology of gray and white MTA set in the presence of fetal bovine serum (FBS). Eight MTA blocks were prepared: four set in the presence of water and four in FBS. The surface morphologic characteristics were studied via scanning electron microscopy. The surface chemical composition of the set cement was investigated by energy dispersive x-ray spectroscopy and x-ray fluorescence. No difference was found between gray and white MTA when set in the same solution. However, MTA/FBS and MTA/water present differing surface morphology and chemical distributions. When set in FBS, MTA's surface had a homogenous distribution of chemicals and a relatively smooth globular appearance. MTA/water's surface was biphasic, containing large hexagonal crystalline plates composed of calcium embedded in a pool of globular crystals.

Dissolution of bio-active dentine matrix components by mineral trioxide aggregate

Objectives To analyze the soluble components of setting and set mineral trioxide aggregate (MTA), assess the abilities of two varieties of MTA and Ca(OH) 2 solutions to solubilise dentine matrix proteins (DMPs) and determine if these extracts contain signalling molecules important to pulpal repair and regeneration. Methods The metallic ion composition of solutions of white and grey MTA (pH 11.7), 0.02 M Ca(OH) 2 (pH 11.9) and 10% EDTA (pH 7.2) was determined using atomic absorption spectroscopy. Extracellular dentine matrix components from powdered human dentine were extracted using all solutions over 14 days. Extracts were analysed for concentrations of non-collagenous proteins (NCPs) and glycosaminoglycans (GAGs), and protein profiles were examined using 1D-polyacrylamide gel electrophoresis (1D-PAGE). ELISAs for TGF-β1 and adrenomedullin (ADM) were also performed. Results Aluminium, calcium, potassium, and sodium ions were detected in both white and grey MTA solutions. MTA and Ca(OH) 2 solutions liberated similar amounts of GAGs and NCPs although yields were considerably lower than those obtained using the EDTA solution. 1D-PAGE analysis demonstrated differences in protein profiles solubilised from dentine for all solutions. All extracts contained TGF-β1 and ADM, EDTA solution liberated significantly greater amounts of TGF-β1, and Ca(OH) 2 and grey MTA solutions released more ADM. Conclusions These data imply that when placed clinically soluble components of set and setting MTA may release dentine matrix components that potentially influence cellular events for dentine repair and regeneration.

The effect of mineral trioxide aggregate on the production of growth factors and cytokine by human periodontal ligament fibroblasts

Mineral trioxide aggregate (MTA) would influence healing of periapical tissues by modulating the production of growth factors and cytokines from PDL fibroblasts, however, the studies are insufficient. Therefore, the purpose of this study was to monitor the expression of transforming growth factor-beta1 (TGF- β 1), fibroblast growth factor-2 (FGF-2), and interleukin-6 (IL-6) from PDL fibroblasts in the presence of MTA. The human PDL fibroblasts were seeded onto the set MTA or IRM at a level of 1 × 10 5 cells per unit well, and further incubated for 6, 12, 24, and 48 hours. The levels of TGF-β 1, FGF-2, and IL-6 from the supernatant were measured by enzyme-linked immunosorbent assay (ELISA). The data were analyzed using one-way ANOVA. The level of TGF-β 1 was down-regulated when the cells were grown in the presence of MTA except at 6 hours. The levels of FGF-2 release were significantly suppressed when PDL fibroblasts were grown in the presence of MTA or IRM at all time intervals (p < 0.05). The expressions of IL-6 from MTA treated cells were comparable to those of untreated control cells throughout the observation periods. We presume that this material inhibits the stimulatory function of growth factors on granulation tissue formation and in turn, it promotes the healing process modulated by other bone-remodeling cells.

Hard-Tissue Healing After Application of Fresh or Set MTA as Root-End-Filling Material

The purpose of this study was to compare the effect of fresh mineral trioxide aggregate (MTA) with set MTA on hard-tissue healing after periradicular surgery. The root canals of 24 mandibular premolars in four 2-yr-old beagle dogs were filled with MTA. Two weeks later the root ends of half of the samples were surgically exposed and resected to the set MTA within the canals. After exposing and resecting the other 12 root ends, they were prepared with ultrasonic instrumentation and preparations were filled with fresh MTA. After 4 months, the animals were killed. Hard-tissue healing was analyzed histomorphometrically. The results indicated that although freshly placed MTA resulted in a significantly higher incidence of cementum formation (12 of 12 versus 8 of 12, p = 0.028), there is no significant difference in the quantity of cementum or osseous healing associated with freshly placed or set MTA when used as root-end-filling material.

Evaluation of Antifungal Activity of Mineral Trioxide Aggregate

The purpose of this investigation was to study, in vitro, the antifungal effect of mineral trioxide aggregate (MTA) using a tube-dilution test. MTA was tested freshly mixed and after 24 h set on Candida albicans. The tested MTA was incubated with C. albicans for 1 h, 24 h, and 3 days. Results showed that the freshly mixed MTA was effective in killing the tested fungi after 1 day of contact, whereas the 24-h set MTA was effective after 3 days of incubation. It was concluded that MTA (freshly mixed and 24-h set) was effective against C. albicans.

Cytotoxicity of four root end filling materials

Leakage and scanning electron microscopic studies have shown that a mineral trioxide aggregate (MTA) used as root end filling material permits significantly less leakage and has better adaptation than other commonly used root end filling materials. Because these materials are in contact with the periradicular tissues, their cytotoxicity should be evaluated before in vivo tests. Using the agar overlay and radiochromium methods, the cytotoxicity of amalgam, Super EBA, IRM, and the MTA was evaluated. Statistical analysis of the data from the agar overlay technique shows that freshly mixed and set amalgam were significantly less toxic than the rest of tested materials (p< 0.00005). Fresh and set MTA ranked second when tested for cytotoxicity with this technique. Similar statistical tests revealed a significant statistical difference between the toxicity of freshly mixed and set materials after 24 h of incubation with radiochromium-labeled mouse L929 cells. The degree of cytotoxicity of fresh and set materials was MTA least toxic followed by amalgam, Super EBA, and IRM. Based on the results of the cell culture methods used in this study it appears that MTA is a potential root end filling material and warrants further in vivo evaluations.