Mineral Trioxide Aggregate Specimens Research Articles

An In vitro Study to Assess the Effectiveness of the Shear Bond Strength of Mineral Trioxide Aggregate with Different Adhesive Systems.

Purpose of the Study:Mineral trioxide aggregate (MTA) is a biocompatible material and has excellent sealing ability. It is proved and claimed that it provides double seal due to its physical sealing ability as well as ability to induce cementogenesis that provides biological seal.Aim and Objectives:The aim of the study was to assess the shear bond strength of MTA with three different types of adhesive systems: (1) self-adhering flowable composite, (2) etch and rinse (ER) adhesive system, and (3) self-etch (SE) adhesive system.Materials and Methods:Ninety MTA specimens were prepared using cylindrical acrylic blocks, having a central cavity with 2 mm depth and 4 mm diameter. MTA was mixed and placed in the prepared cavity and was covered with moist cotton pellet and temporary filling material (Cavit). They were further divided into three groups which were further divided into two subgroups. After the bonding agents was applied, the composite resin was placed over the MTA surface. The specimens were then tested for shear bond strength; statically analysis was done.Result:After 24 h, the mean value of ER group was found to be significantly higher than SE and the self-adhering composite groups. Among the 45 min groups, there was no significant difference observed.Conclusion:In single visit, after 45 min, self-adhering flowable can be used successfully as a final restorative material in place of conventional flowable composite without using any alternative adhesive system over MTA.

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.

Mineral Trioxide Aggregate Mixed with 5-Aminolevulinic Acid for the Photodynamic Antimicrobial Strategy in Hard Tissue Regeneration.

Aminolevulinic acid (ALA) based photodynamic antimicrobial strategy can provide good antimicrobial effects and be used for medical applications. The aim of this study was to apply this strategy to Mineral Trioxide Aggregate (MTA), which is commonly used as a filling material for root endings and by doing so, to increase the bactericidal capability of MTA, as well as to investigate its characterization, cytocompatibility, and odontogenic differentiation potential. MTA is known to be a derivative of calcium silicate (CS). In this study, MTA specimens with or without ALA and light treatment were prepared. Diametral tensile strength values (DTS), setting durations, X-ray diffraction (XRD) spectra, apatite-mineralization, and antimicrobial abilities of the MTA, were also analyzed. Human dental pulp cells (hDPCs) can proliferate into the newly formed matrix and differentiate into odontoblasts to reinforce and strengthen the root. Levels of hDPCs proliferation and its odontogenic capabilities when cultured on MTA with ALA and light treatment, and the percentages of cells existing in the various cell cycle stages, were further evaluated in this study. The results indicated that MTA added ALA with light treatment had greater antibacterial ability and cytocompatibility, compared to MTA alone. A higher percentage S phase of the cells cultured on MTA added ALA with light treatment was observed. Furthermore, hDPCs cultured on MTA added ALA with light treatment had the highest expression levels of the odontoblastic differentiation markers. ALA has great antimicrobial efficiency and is a potential material for future medical applications. ALA-based photodynamic antibacterial strategy applied in the MTA has great antibacterial ability, cytocompatibility, and odontoblastic differentiation potential, and can facilitate the development of root canal treatment.

Effects of Three Calcium Silicate Cements on Inflammatory Response and Mineralization-Inducing Potentials in a Dog Pulpotomy Model.

This beagle pulpotomy study compared the inflammatory response and mineralization-inducing potential of three calcium silicate cements: ProRoot mineral trioxide aggregate (MTA) (Dentsply, Tulsa, OK, USA), OrthoMTA (BioMTA, Seoul, Korea), and Endocem MTA (Maruchi, Wonju, Korea). Exposed pulp tissues were capped with ProRoot MTA, OrthoMTA, or Endocem MTA. After 8 weeks, we extracted the teeth, then performed hematoxylin-eosin and immunohistochemical staining with osteocalcin and dentin sialoprotein. Histological evaluation comprised a scoring system with eight broad categories and analysis of calcific barrier areas. We evaluated 44 teeth capped with ProRoot MTA (n = 15), OrthoMTA (n = 18), or Endocem MTA (n = 11). Most ProRoot MTA specimens formed continuous calcific barriers; these pulps contained inflammation-free palisading patterns in the odontoblastic layer. Areas of the newly formed calcific barrier were greater with ProRoot MTA than with Endocem MTA (p = 0.006). Although dentin sialoprotein was highly expressed in all three groups, the osteocalcin expression was reduced in the OrthoMTA and Endocem MTA groups. ProRoot MTA was superior to OrthoMTA and Endocem MTA in all histological analyses. ProRoot MTA and OrthoMTA resulted in reduced pulpal inflammation and more complete calcific barrier formation, whereas Endocem MTA caused a lower level of calcific barrier continuity with tunnel defects.

Effect of Blood Exposure on Push-Out Bond Strength of Four Calcium Silicate Based Cements.

Introduction:The purpose of this study was to compare the push-out bond strength of white ProRoot Mineral Trioxide Aggregate (MTA), Biodentine, calcium-enriched mixture (CEM) cement and Endosequence Root Repair Material (ERRM) putty after exposure to blood. Methods and Materials:A total of 96 root dentin slices with a standardized thickness of 1.00±0.05 mm and standardized canal spaces were randomly divided into 4 main experimental groups (n=24) according to the calcium silicate based cement (CSC) used: white ProRoot MTA, CEM Cement, ERRM Putty and Biodentine. Specimens were exposed to whole fresh human blood and then subdivided into two subgroups depending on the exposure time (24 or 72 h). Push-out bond strength was measured using a universal testing machine. Failure modes were examined under a light microscope under ×10 magnification. Data were analyzed using the two-way ANOVA test. Results:Biodentine exhibited the highest values regardless of the exposure time. The lowest push-out strength values were seen in white ProRoot MTA and CEM cement in both post exposure times. After exposure to blood, the push-out bond strength of all materials increased over time. This increase was only statistically significant in white ProRoot MTA and ERRM specimens. The dominant failure mode in all CSCs was the adhesive mode. Conclusion:Biodentine showed the highest values of push-out bond strength and may be better options for situations encountering higher dislocation forces in a short time after cement application.

Biological efficacy of two mineral trioxide aggregate (MTA)-based materials in a canine model of pulpotomy.

The aim of this study was to compare the biocompatibility of Endocem Zr® and ProRoot MTA® by histopathologic analysis in a canine model of pulpotomy. This study utilized 39 teeth of two beagle dogs. The exposed pulp tissues were treated by pulpotomy using ProRoot MTA (n=19) or Endocem Zr (n=20). After 8 weeks, the teeth were extracted and processed with hematoxylin-eosin staining for histologic evaluation. Most of the specimens in both groups developed a calcific barrier at the pulp amputation site and formed an odontoblast layer. However, some of the Endocem Zr specimens showed less calcific barrier formation with a greater inflammatory response and less odontoblast layer formation when compared with the ProRoot MTA specimens. ProRoot MTA and Endocem Zr specimens developed a calcific barrier; however, ProRoot MTA was more biocompatible than Endocem Zr.

The Effect of Mineral Trioxide Aggregate Mixed with Chlorhexidine as Direct Pulp Capping Agent in Dogs Teeth: A Histologic Study.

Introduction:The aim of the present investigation was to compare the efficacy of mineral trioxide aggregate (MTA) and 0.2% chlorhexidine (CHX) mixture to pure MTA, as a pulp capping material.Methods and Materials:The pulp of 24 lateral incisors and canines from four dogs were exposed and capped either with MTA or MTA+0.2% CHX. After 2 months the animals were sacrificed and the teeth were prepared for histological evaluation in terms of calcified bridge formation, the degree of inflammation and presence of necrosis. The Fisher’s exact test was used for data analysis. Results: The results showed that formation of complete calcified bridge in MTA specimens was significantly more than MTA+CHX (P<0.05). No significant difference was found in the degree of inflammation and necrosis between MTA and MTA+CHX groups (P>0.05). Conclusion:Mixing MTA with CHX as pulp capping agent had a significant negative impact on formation of calcified bridge on directly capped dog’s teeth.

Evaluation of reparative dentin formation of ProRoot MTA, Biodentine and BioAggregate using micro-CT and immunohistochemistry

ObjectivesThe purpose of this study was to assess the ability of two new calcium silicate-based pulp-capping materials (Biodentine and BioAggregate) to induce healing in a rat pulp injury model and to compare them with mineral trioxide aggregate (MTA).Materials and MethodsEighteen rats were anesthetized, cavities were prepared and the pulp was capped with either of ProRoot MTA, Biodentine, or BioAggregate. The specimens were scanned using a high-resolution micro-computed tomography (micro-CT) system and were prepared and evaluated histologically and immunohistochemically using dentin sialoprotein (DSP).ResultsOn micro-CT analysis, the ProRoot MTA and Biodentine groups showed significantly thicker hard tissue formation (p < 0.05). On H&E staining, ProRoot MTA showed complete dentin bridge formation with normal pulpal histology. In the Biodentine and BioAggregate groups, a thick, homogeneous hard tissue barrier was observed. The ProRoot MTA specimens showed strong immunopositive reaction for DSP.ConclusionsOur results suggest that calcium silicate-based pulp-capping materials induce favorable effects on reparative processes during vital pulp therapy and that both Biodentine and BioAggregate could be considered as alternatives to ProRoot MTA.

Effect of Varying Water-to-Powder Ratios and Ultrasonic Placement on the Compressive Strength of Mineral Trioxide Aggregate

IntroductionThe purpose of this study was to compare the compressive strength of mineral trioxide aggregate (MTA) when mixed with 2 different water-to-powder (WP) proportions using either hand or ultrasonic placement. MethodsTooth-colored ProRoot MTA (Dentsply Maillefer, Ballaigues, Switzerland) and white MTA Angelus (Angelus Soluçoes Odontologicas, Londrina, Brazil) were investigated. One gram of each MTA powder was mixed with either 0.34 or 0.40 g distilled water. The 4 groups were further divided into 2 groups of 5 specimens for each of the following techniques: conventional (ie, hand placement) and placement using indirect ultrasonic activation for 30 seconds. All specimens were subjected to compressive strength testing after 4 days. The results were statistically analyzed with multivariate analysis of variance and Tukey Honestly Significant Difference tests at a significance level of P < .05. ResultsThe mean compressive strength values of ProRoot MTA (84.17 ± 22.68) were significantly greater than those of MTA Angelus (47.71 ± 14.29) (P < .01). Specimens mixed with the 0.34 WP ratio had higher compressive strength values (72.85 ± 25.77) than those mixed with the 0.40 WP ratio (56.69 ± 24.85) (P < .05). The highest compressive strength values were recorded for ProRoot MTA specimens that were mixed in the 0.34 WP ratio, and then the samples were placed with ultrasonic activation (mean = 91.35 MPa). The lowest values were recorded for MTA Angelus samples that were mixed in the 0.40 WP ratio, and the specimens were placed without ultrasonic activation (mean = 36.36 MPa). Ultrasonic activation had no significant difference in terms of compressive strength. ConclusionsWhen using ProRoot MTA and MTA Angelus, higher WP ratios resulted in lower compressive strength values. Ultrasonication had no significant effect on the compressive strength of the material regardless of the WP ratio that was used. Therefore, adherence to the manufacturer's recommended WP ratio when preparing MTA for use in dental applications is advised.

The effect of acid-etch procedure on the bond between composite resin and mineral trioxide aggregate

Introduction: This study measured the contact angles of mineral trioxide aggregate (MTA) and the shear bond strengths of composite resin to MTA with and without acid-etch procedures. Methods: twenty-seven MTA specimens were prepared. The contact angles were measured using 7 specimens before and after acid-etch procedure. The remaining 20 specimens were divided into 2 groups, each with 10 specimens. Acid-etch procedure was done on etched group and not on non-etched group. Then, Scotchbond Multipurpose (3M ESPE, St Paul, MN, USA) was applied and composite resin was built. Shear bond strengths were measured using universal testing machine, and the data were subjected to Mann-Whitney U test. Results: After acid-etching procedure, the average contact angle was significantly lower than that of unetched MTA surface (p<0.05). MTA Specimens with acid-etch procedure showed a significantly higher bond strength than that without acid-etch procedure (p<0.05). Conclusions: Acid-etch procedure improved the wettability of MTA surface and the bond strength between MTA and composite resin.

Evaluation of the rat tissue reaction to experimental new resin cement and mineral trioxide aggregate cement

ObjectivesNew resin cement (NRC) has been developed as a root repairing material and the material is composed of organic resin matrix and inorganic powders. The aim of this study was to compare the rat subcutaneous tissue response to NRC and mineral trioxide aggregate (MTA) cement and to investigate the tissue toxicity of both materials.Materials and MethodsSixty rats received two polyethylene tube-implants in dorsal subcutaneous regions, MTA and NRC specimens. Twenty rats were sacrificed respectively at 1, 4 and 8 wk after implantation and sectioned to 5 µm thickness and stained with Hematoxylin-Eosin (H-E) or von-Kossa staining. The condition of tissue adjacent to the implanted materials and the extent of inflammation to each implant were evaluated by two examiners who were unaware of the type of implanted materials in the tissues. Data were statistically analyzed with paired t-test (p < 0.05).ResultsIn specimens implanted with both NRC and MTA, severe inflammatory reactions were present at one wk, which decreased with time. At eighth wk, MTA implanted tissue showed mild inflammatory reaction, while there were moderate inflammatory reactions in NRC implanted tissue, respectively. In NRC group, von-Kossa staining showed more calcification materials than MTA group at eighth wk.ConclusionsIt was concluded that the calcium reservoir capability of NRC may contribute to mineralization of the tissues.

Short-term antimicrobial properties of mineral trioxide aggregate with incorporated silver-zeolite

The purpose of this in vitro study was to determine whether adding silver-zeolite (SZ) to mineral trioxide aggregate (MTA) would enhance the antimicrobial activity of MTA against Staphylococcus aureus (ATCC #25923), Enterococcus faecalis (ATCC #29212), Escherichia coli (ATCC#25922), Pseudomonas aeruginosa (ATCC #27853), Candida albicans (ATCC #90028), Porphyromonas gingivalis (ATCC #33277), Actinomyces israelii (ATCC #12102), and Prevotella intermedia (ATCC# 15032). SZ was added at 0.2% and 2% mass fraction concentration to MTA powder. The control group was MTA powder with no SZ. The antimicrobial effect test was accomplished by placing freshly mixed MTA specimens on agar plates inoculated with microorganisms and comparing the zones of inhibition at 24, 48, and 72 h. The amounts of silver ion release from MTA specimens were measured with atomic absorption spectrophotometry at 10-min, 24-, 48-, and 72-h periods. The pH of MTA specimens was measured with a pH meter at 10-min, 24-, 48-, and 72-h periods. MTA with 2% and 0.2% SZ specimens showed inhibitory effects on some microorganisms at all time periods, whereas no antimicrobial activity showed for P. intermedia and A. israelii. MTA without SZ inhibited C. albicans, E. Coli, and P. intermedia. The highest silver release was detected in 2% SZ MTA at 24 h. The incorporation of SZ may enhance the antimicrobial activity of MTA.

Effect of ProRoot MTA, Portland cement, and amalgam on the expression of fibronectin, collagen I, and TGFβ by human periodontal ligament fibroblasts in vitro

Today many materials have been introduced for root-end filling materials. One of them is mineral trioxide aggregate (MTA) that is mentioned as a gold standard. The purpose of this in vitro study was to evaluate the reaction of human periodontal ligament fibroblasts to the root-end filling materials, such as ProRoot MTA, Portland cement, and amalgam. Eight impacted teeth were extracted in aseptic condition. The tissues around the roots were used to obtain fibroblast cells. After cell proliferation, they were cultured in the chamber slides and the extracts of the materials were added to the wells. Immunocytochemical method for measuring the expression of Fibronectin, collagen I and transforming growth factor beta (TGF®) was performed by Olysia Bioreport Imaging Software. The results were analyzed by SPSS 13.0 and Tukey post hoc test with P<0.05 as the limit of significance. Collagen expression in MTA specimens was higher than the other groups in 24 h significantly. After 48 h, the Portland cement group showed the most expression of collagen significantly and after 1 week, Portland cement and MTA groups had the most expression of collagen but there was no significant difference between these 2 groups. After 1 week, the Portland cement group demonstrated a higher amount of TGF® and fibronectin. The results suggest that Portland cement can be used as a less expensive root filling material with low toxicity. It has better effects than amalgam on the fibroblasts.

Cytotoxic effects of White-MTA and MTA-Bio cements on odontoblast-like cells (MDPC-23)

This study evaluated the cytotoxic effects of 2 mineral trioxide aggregate (MTA) cements - White-MTA-Angelus and a new formulation, MTA-Bio - on odontoblast-like cell (MDPC-23) cultures. Twenty-four disc-shaped (2 mm diameter x 2 mm thick) specimens were fabricated from each material and immersed individually in wells containing 1 mL of DMEM culture medium for either 24 h or 7 days to obtain extracts, giving rise to 4 groups of 12 specimens each: G1 - White-MTA/24 h; G2 - White-MTA/7 days; G3 - MTA-Bio/24 h; and G4 - MTA-Bio/7 days. Plain culture medium (DMEM) was used as a negative control (G5). Cells at 30,000 cells/cm(2) concentration were seeded in the wells of 24-well plates and incubated in a humidified incubator with 5% CO2 and 95% air at 37 degrees C for 72 h. After this period, the culture medium of each well was replaced by 1 mL of extract (or plain DMEM in the control group) and the cells were incubated for additional 2 h. Cell metabolism was evaluated by the MTT assay and the data were analyzed statistically by ANOVA and Tukey's test (alpha=0.05). Cell morphology and the surface of representative MTA specimens of each group were examined by scanning electron microscopy. There was no statistically significant difference (p>0.05) between G1 and G2 or between G3 and G4. No significant difference (p>0.05) was found between the experimental and control groups either. Similar cell organization and morphology were observed in all groups, regardless of the storage periods. However, the number of cells observed in the experimental groups decreased compared to the control group. MTA-Bio presented irregular surface with more porosities than White-MTA. In conclusion, White-MTA and MTA-Bio presented low cytotoxic effects on odontoblast-like cell (MDPC-23) cultures.

Effects of EDTA on the Hydration Mechanism of Mineral Trioxide Aggregate

Ethylenediaminetetraacetic acid (EDTA) is commonly used during the preparation of obstructed root canals that face a high risk of root perforation. Such perforations may be repaired with mineral trioxide aggregate (MTA). Due to EDTA's ability to chelate calcium ions, we hypothesized that EDTA may disrupt the hydration of MTA. Using scanning electron microscopy and energy-dispersive x-ray spectroscopy, we found that MTA specimens stored in an EDTA solution had no crystalline structure and a Ca/Si molar ratio considerably lower than those obtained for specimens stored in distilled water and normal saline. Poor cell adhesion in EDTA-treated MTA was also noted. X-ray diffraction indicated that the peak corresponding to portlandite, which is normally present in hydrated MTA, was not shown in the EDTA group. The microhardness of EDTA-treated specimens was also significantly reduced (p < 0.0001). These findings suggest that EDTA interferes with the hydration of MTA, resulting in decreased hardness and poor biocompatibility.

Effect of Setting Conditions on Mineral Trioxide Aggregate Flexural Strength

This study evaluated the effect of setting conditions (time and hydration) on mineral trioxide aggregate (MTA) flexural strength. MTA beam specimens were allowed to set for either 24 or 72 hours with specimens exposed to moisture on either one or two specimen surfaces. These moisture conditions were used to simulate MTA setting with only external tissue moisture (one-sided moisture) versus tissue moisture in combination with a moistened intracanal cotton pellet (two-sided moisture). Ten specimens were stored at 37°C under each of the four experimental setting conditions (1) 24-hour/moist/2-sided; (2) 24-hour/moist/1-sided; (3) 72-hour/moist/2-sided; (4) 72-hour/moist/1-sided. After storage at respective setting conditions, MTA specimens were tested to failure with three-point bend test to measure flexural strength. Flexural strength of the 24h/moist/2-sided specimens, 14.27 ± 1.96 MPa, was significantly higher (p ≤ 0.05) than the flexural strength values associated with conditions two, three, and four, respectively, 10.77 ± 1.44, 11.16 ± 0.96, 11.18 ± 0.99 MPa, which were not significantly different from each other (p > 0.05). Clinically, these results suggest that a moistened cotton pellet should be placed on the intracanal MTA surface under a temporary restoration; and if possible, to optimize flexural strength, the moistened pellet should only remain in place for 24 hours.

Effect of ProRoot® MTA mixed with chlorhexidine on apoptosis and cell cycle of fibroblasts and macrophages in vitro*

To compare the percentage of apoptotic cells and the cell cycle profile of fibroblasts and macrophages exposed to either ProRoot mineral trioxide aggregate (MTA) mixed with chlorhexidine (CHX), or exposed to ProRoot MTA mixed with sterile water. Mouse gingival fibroblasts or mouse macrophages were seeded in six-well plates and allowed to attach overnight. Freshly mixed or set (allowed to dry for 24 h) specimens of tooth-coloured (white) ProRoot MTA were prepared with 0.12% CHX gluconate (MTA/CHX) or with sterile water (MTA/H2O). The cells were exposed for 24 h to the MTA specimens, which were placed over permeable membrane inserts to avoid direct contact with the cells. Untreated cells served as controls. Propidium iodide staining followed by flow cytometry was used to evaluate the effects of ProRoot MTA on cell apoptosis and cell cycle. Statistical analyses were performed by one-way anova followed by post-hoc tests with the use of the SigmaStat 2.0 software, and significance was determined at P < or = 0.05. MTA specimens containing CHX induced apoptosis of macrophages and fibroblasts (P < 0.05). In contrast, no change in the proportion of apoptotic cells was observed when sterile water was used to prepare the specimens (P > 0.05). Cell cycle analysis showed that exposure to MTA/CHX decreased the percentage of fibroblasts and macrophages in S phase (DNA synthesis) as compared with exposure to MTA/H2O (P < 0.05). This in vitro study demonstrated that the substitution of CHX for sterile water in MTA increases its cytotoxicity. This suggests that the potentially beneficial antimicrobial effect of CHX may be accompanied by an increase in the cytotoxicity of the resulting MTA-based material.