White Mineral Trioxide Aggregate Angelus Research Articles

Morphological and Chemical Analysis of Different Types of Calcium Silicate-Based Cements.

Objectives Particle size and shape can influence the properties of materials. However, to improve the physicochemical and biological properties of mineral trioxide aggregate (MTA), silicate-based hydraulic cements were introduced. This study aimed to evaluate and compare the major constituents and crystalline structures along with the surface morphology of different types of calcium silicate-based cement (CSC). Materials and Methods Six different types of CSC (white Portland cement, white ProRoot MTA, white MTA Angelus, Biodentine, and Endosequence, both putty and paste) were used in this study. Five samples of each material were analyzed in both uncured and cured cement using scanning electron microscopy/energy-dispersive X-ray (SEM/EDX), X-ray diffraction (XRD), and Fourier transform-infrared spectroscopy (FTIR). Results SEM analysis showed that the surfaces of all materials consisted of particle sizes ranging from 0.194 μm to approximately 51.82 μm. The basic elements found in both uncured and cured cement of all tested materials using EDX were carbon, calcium, silicon, and oxygen. A difference was observed in the presence or absence of magnesium, aluminum, bismuth, zirconium, and tantalum. XRD showed that all tested materials were composed mainly of tricalcium silicate and dicalcium silicate, which are the main components of Portland cement. FTIR analysis showed aromatic rings, phosphine PH, alkyl halides, and alcohol O-H groups in all tested materials but at different wavenumbers. Conclusions The different types of CSCs tested in this study were primarily modified types of Portland cement with the addition of radiopacifiers. ProRoot MTA and MTA Angelus contained bismuth oxide, Biodentine contains zirconium oxide, whereas Endosequence root repair materials (both putty and paste) contained zirconium oxide and tantalum oxide. Endosequence root repair materials showed smaller particle sizes than the other groups. White PC had the most irregular and large particle sizes. CSC had a smaller particle size, except for MTA Angelus. Clinical Relevance. The composition of CSC has a direct influence on the properties of these cements, which may affect the clinical outcome of the treatment.

Effect of commonly used irrigants on the colour stabilities of two calcium-silicate based material.

The aim of present study was to evaluate the color stability of calcium-silicate based cements (CSC) Mineral Trioxide Aggregate (MTA) and BiodentineTM when exposed to endodontic irrigating solutions 5% Sodium hypochlorite (NaOCl) or 2% Chlorhexidine (CHX). A total of 60 (n=30) cylindrical samples (10 mm diameter, 2 mm height) were prepared by manipulating white MTA Angelus (Angelus, Londrina, PR, Brazil) and BiodentineTM (Septodent, Saint Maur, France) according to manufacturer's instructions. These samples were immersed in 5% sodium hypochlorite (Prime Dental Products Pvt. Ltd., Mumbai, India), 2% chlorhexidine gluconate (Dentochlor, Saronno VA, Italia), or distilled water for 24 hours. Color changes were measured using UV spectrophotometer (UV-1650, Shimadzu, Europe) and the values were tabulated. A significant difference was observed between group I and II with respect to both parameters A & B (p<0.05). Both the calcium-silicate-based materials exhibited significant discoloration when immersed in NaOCl and CHX. Distilled water did not cause clinically perceptible discoloration of any material. A significant discoloration was observed with a specific combination of calciumsilicate- based cement and irrigant. BiodentineTM exhibited significant discoloration with CHX whereas, MTA showed more discoloration with NaOCl.

Addition of phosphates and chlorhexidine to resin‐modified MTA materials

To evaluate the properties of experimental mineral trioxide aggregate (MTA) resin-modified materials for root-end filling procedures, varying their compositions regarding the addition of hydroxiapatite (HA) or dicalcium phosphate dihydrate, with or without chlorhexidine digluconate. White MTA (Angelus, Londrina, Brazil) was used as a reference material. Degree of conversion (DC) was evaluated by Fourier transformed infrared (FTIr) spectroscopy (n = 5). Flowability (n = 3) and radiopacity (n = 3) were evaluated following ISO 6876:2001 methods. For splitting tensile strength analysis, cylindrical samples (n = 10) were subjected to compressive load using a universal testing machine (Instron Corporation, Norwood, MA). Water sorption and solubility tests were performed according to ISO 4049:2009 methods. Calcium ion release and pH analysis (n = 10) were evaluated using a pH meter (Orion, Watsonville, CA). Cytotoxicity (n = 8) of materials extracts was evaluated as cell viability percentage. Statistical analysis was performed using Kolmogorov-Smirnov for normal distribution and data was subjected to one-way ANOVA and Tukey test (α = 0.05). Addition of chlorhexidine digluconate reduced DC mean values for experimental materials (<50%). White MTA demonstrated lower flowability (5.3 mm) and higher radiopacity (9.8 mm Al), splitting tensile strength (9.1 MPa), solubility (8.2 μg/mm3 ), calcium ion release (~26.5 ppm), cytotoxicity (55.2%), and pH mean values (10.8), when compared to experimental materials. All groups demonstrated a decrease in calcium release (<85%) and pH (<13%). Formulation containing HA demonstrated similar pH values after 28 days when compared to white MTA. Evaluated experimental resin-modified MTA based materials without chlorhexidine digluconate showed satisfactory results for all physico-chemical properties tested and cytotoxicity. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2195-2201, 2019.

Assessment of tooth discoloration induced by biodentine and white mineral trioxide aggregate in the presence of blood

Introduction:In clinical dental application, using silicate-based cements is extremely popular. These materials come into direct contact with blood during or after placement and may cause tooth discoloration.Objectives:The purpose of this study was to compare the coronal tooth discoloration induced by white mineral trioxide aggregate (MTA) and biodentine in the presence of blood.Materials and Methods:Seventy specimens were chemomechanically prepared and divided into four experimental and two control groups. In the experimental groups, the pulp chambers were filled with white MTA angelus or biodentine. Blood or saline saturated cotton pellets were placed within the canals. Saline or blood alone was used in the control groups. Color was assessed with a spectrophotometer at baseline, 1 week, and 1 and 3 months, and color change values were calculated. Tukey's honestly significant difference and Sidak tests were used for statistical analysis.Results:The color change was significantly less with biodentine/saline than MTA/saline and MTA/blood (P < 0.05). Regardless of the material type and blood presence, discoloration increased after 3 months (P < 0.05).Conclusion:Discoloration induced by biodentine/saline may not be clinically noticeable and it was less than MTA-containing groups. Irrespective of blood presence or absence, MTA caused perceptible color change.

Zinc Oxide Inhibits Dental Discoloration Caused by White Mineral Trioxide Aggregate Angelus

IntroductionThe aim of the study was to investigate the addition of variable amounts of zinc oxide to inhibit dental discoloration caused by mineral trioxide aggregate (MTA) Angelus. MethodsMTA Angelus and MTA with additions of 5%, 15%, and 45% zinc oxide (ZnO) in weight were tested. The set cements were characterized by using a combination of scanning electron microscopy, energy dispersive spectroscopy, and x-ray diffraction. Radiopacity and setting time were analyzed according to American National Standards Institute/American Dental Association (57/2012) and American Society for Testing and Materials (C266-08). Volume change was evaluated by using micro–computed tomography analysis. The pH and calcium ion release were measured after 3 hours, 24 hours, and 28 days. Dental discoloration in contact with the cements was measured after 24 hours, 28 days, and 90 days. Biocompatibility to subcutaneous implantation in rats was verified after 30 and 60 days. ResultsAddition of ZnO did not alter significantly the radiopacity, setting time, volume change, pH, and biocompatibility compared with MTA Angelus (P > .05). Calcium ion release increased with addition of ZnO (P < .05). Proportions of 15% and 45% ZnO interfered in hydration. The 5% ZnO addition was sufficient to prevent the dental discoloration observed with MTA Angelus. ConclusionsThe addition of 5%, 15%, or 45% zinc oxide to MTA Angelus inhibits dental discoloration without modifying the radiopacity, setting time, volume change, pH, and biocompatibility.

Push-out Bond Strength of Fast-setting Mineral Trioxide Aggregate and Pozzolan-based Cements: ENDOCEM MTA and ENDOCEM Zr

IntroductionThe present study investigated the root canal dentin bond strength of 2 newly developed fast-setting mineral trioxide aggregate (MTA) and pozzolan-based cements: ENDOCEM MTA (Maruchi, Wonju, Korea) and ENDOCEM Zr (Maruchi). White MTA (Angelus, Londrina, Brazil) was used as the reference material for comparison. MethodsRoot slices (1 mm ± 0.1 mm) were obtained from the middle third of 15 maxillary incisors previously selected. Three canal-like holes (0.8 diameter) were drilled perpendicularly on the axial surface of each root slice. A standardized irrigation protocol was applied for all samples, and after drying, each hole was filled with 1 of 3 test repair materials. Finally, slices were stored in contact with phosphate-buffered saline solution (pH = 7.2) for 7 days at 37°C before the push-out assay. Data were nonparametrically evaluated at α = 5%. ResultsThe Friedman test was unable to confirm a significant dissimilarity in push-out ranks among the tested cements (P = .220). ConclusionsThe new fast-setting MTA and pozzolan-based cements ENDOCEM MTA and ENDOCEM Zr present suitable bond strength performance, which is comparable with white MTA.

Effect of root canal irrigating solutions on the compressive strength of tricalcium silicate cements.

The aim of this study was to evaluate the effect of root canal irrigants on the compressive strength of hydraulic tricalcium silicate cements. Specimens (n=60) of tricalcium silicate materials-Group 1: White ProRoot mineral trioxide aggregate (MTA), Group 2: NeoMTA Plus, Group 3: White MTA Angelus, and Group 4: Biodentine were exposed to one of the solutions (n=20): Phosphate buffered saline (PBS; control), 3% NaOCl, or 17% EDTA for 5min while being suspended in PBS. Compressive strength values were evaluated after 7days of storage. The data were statistically analyzed by two-way ANOVA and Tukey's multiple comparison test (P=0.05). Biodentine (BD) showed significantly higher compressive strength than the other materials (P<0.05) in the control group. When exposed to NaOCl, compressive strength of WMTA and WMTA-A decreased significantly (P<0.05), while EDTA decreased the compressive strength of all the cements compared to the control (P<0.05). There was no significant difference in the compressive strength of BD and NMTA-P when exposed to NaOCl or EDTA. Biodentine and NeoMTA Plus did not show a significant reduction in compressive strength when exposed to NaOCl. EDTA reduced the compressive strength of the cements tested. Tricalcium silicates were differentially influenced by root canal irrigants. It is essential to understand the composition of these materials prior to clinical use. Traces of irrigants from the root canal wall must be thoroughly removed.

Fracture resistance of immature teeth filled with mineral trioxide aggregate, bioaggregate, and biodentine

Objective:The purpose of this study was to evaluate fracture resistance of teeth with immature apices treated with coronal placement of mineral trioxide aggregate (MTA), bioaggregate (BA), and Biodentine.Materials and Methods:Forty-one freshly extracted, single-rooted human premolar teeth were used for the study. At first, the root length was standardized to 9 mm. The crown-down technique was used for the preparation of the root canals using the rotary ProTaper system (Dentsply Maillefer, Ballaigues, Switzerland) of F3 (30). Peeso reamer no. 6 was stepped out from the apex to simulate an incompletely formed root. The prepared roots were randomly assigned to one control (n = 5) and three experimental (n = 12) groups, as described below. Group 1: White MTA (Angelus, Londrina, Brazil) was prepared as per the manufacturer's instructions and compacted into the root canal using MAP system (Dentsply Maillefer, Ballaigues, Switzerland) and condensed by pluggers (Angelus, Londrina, Brazil). Group 2: The canals were filled with DiaRoot-BA (DiaDent Group International, Canada). Group 3: Biodentine (Septodont, Saint Maur des Fosses, France) solution was mixed with the capsule powder and condensed using pluggers. Instron was used to determine the maximum horizontal load to fracture the tooth, placing the tip 3 mm incisal to the cementoenamel junction. Mean values of the fracture strength were compared by ANOVA followed by a post hoc test. P < 0.05 was considered statistically significant.Results:No significant difference was observed among the MTA, BA, and biodentine experimental groups.Conclusion:All the three materials tested, may be used as effective strengthening agents for immature teeth.

"Evaluation of shear bond strength of a composite resin to white mineral trioxide aggregate with three different bonding systems"-An in vitro analysis.

BackgroundMineral trioxide aggregate (MTA) is a biomaterial that has been investigated for endodontic applications. With the increased use of MTA in pulp capping, pulpotomy, perforation repair, apexification and obturation, the material that would be placed over MTA as a final restoration is an important matter. As composite resins are one of the most widely used final restorative materials, this study was conducted to evaluate the shear bond strength of a composite resin to white mineral trioxide aggregate (WMTA) using three different bonding systems namely the two-step etch and rinse adhesive, the self-etching primer and the All-in-one system.Material and MethodsForty five specimens of white MTA (Angelus) were prepared and randomly divided into three groups of 15 specimens each depending on the bonding systems used respectively. In Group A, a Two-step etch and rinse adhesive or ‘total-etch adhesive’, Adper Single Bond 2 (3M/ESPE) and Filtek Z350 (3M ESPE, St Paul, MN) were placed over WMTA. In group B, a Two-step self-etching primer system, Clearfil SE Bond (Kuraray, Medical Inc) and Filtek Z350 were used. In Group C, an All-in-one system, G Bond (GC corporation, Tokyo, Japan) and Filtek Z350 were used. The shear bond strength was measured for all the specimens. The data obtained was subjected to One way Analysis of Variance (ANOVA) and Scheffe’s post hoc test.ResultsThe results suggested that the Two-step etch and rinse adhesive when used to bond a composite resin to white MTA gave better bond strength values and the All-in-one exhibited the least bond strength values.ConclusionsThe placement of composite used with a Two-step etch and rinse adhesive over WMTA as a final restoration may be appropriate. Key words:Composite resins, dentin bonding agents, mineral trioxide aggregate, shear bond strength.

In vitro Evaluation of the Efficacy of 2% Carbonic Acid and 2% Acetic Acid on Retrieval of Mineral Trioxide Aggregate and their Effect on Microhardness of Dentin

In this in vitro study, the efficacy of 2% carbonic acid and 2% acetic acid on the surface, microhardness of white mineral trioxide aggregate (MTA) and dentin after 1 day of setting and 21 days of setting of MTA is measured. Tooth molds were made using 60 single-rooted premolars by slicing them to 4 mm in the mid-root region. White MTA (Angelus) was mixed and packed in the molds. Three experimental groups were formed and exposed to 2% carbonic acid, 2% acetic acid, and saline for 10 minutes on 1 and 21 days of setting respectively. Vickers hardness test of white MTA and dentin was done before and after exposure. Data were subjected to analysis of variance (ANOVA) and post hoc tests. The results show that 2% acetic acid was significantly effective in reducing the microhardness of white MTA compared to 2% carbonic acid and saline on exposure for 10 minutes. The results of the present study indicate that 2% acetic acid has maximum efficacy in reducing the surface microhardness of partial and completely set MTA, followed by 2% carbonic acid. The following study will help find an adjunct for retrieval of MTA, which was found difficult with the existing methods.

Effect of bleaching agents having a neutral pH on the surface of mineral trioxide aggregate using electron microscopy and energy dispersive X-ray microanalysis.

Aim:To investigate the effect of bleaching agents having a neutral pH on the surface of mineral trioxide aggregate (MTA) used as a coronal seal material for nonvital bleaching, beneath the bleaching agent, with the help of energy dispersive X-ray microanalysis and scanning electron microscopy (SEM).Materials and Methods:Six samples of plastic tubes filled with white MTA (Angelus white) were kept in 100% humidity for 21 days. Each sample was divided into 2 and made into 12 samples. These were then divided into three groups. Group A was exposed to Opalescence Boost 40% hydrogen peroxide (HP) (Ultradent). Group B to Opalescence 10% carbamide peroxide (Ultradent) and Group C (control group) not exposed to any bleaching agent. After recommended period of exposure to bleaching agents according to manufacturers’ instructions, the samples were observed under SEM with an energy dispersive X-ray microanalysis system (JSM-6380 LA).Results:There were no relevant changes in color and no statistically significant surface structure changes of the MTA in both the experimental groups.Conclusion:The present findings suggest that even high concentration HP containing bleaching agents with neutral pH can be used on the surface of MTA without causing structural changes. The superior sealing ability of MTA and the high alkalinity would prevent cervical resorption postbleaching.

Experimental Calcium Silicate-Based Cement with and without Zirconium Oxide Modulates Fibroblasts Viability.

The aim of this study was to verify whether the use of zirconium oxide as a radiopacifier of an experimental calcium silicate-based cement (WPCZO) leads to cytotoxicity. Fibroblasts were treated with different concentrations (10 mg/mL, 1 mg/mL, and 0.1 mg/mL) of the cements diluted in Dulbecco's modified Eagle's medium (DMEM) for periods of 12, 24, and 48 h. Groups tested were white Portland cement (WPC), white Portland cement with zirconium oxide (WPCZO), and white mineral trioxide aggregate Angelus (MTA). Control group cells were not treated. The cytotoxicity was evaluated through mitochondrial-activity (MTT) and cell-density (crystal violet) assays. All cements showed low cytotoxicity. In general, at the concentration of 10 mg/mL there was an increase in viability of those groups treated with WPC and WPCZO when compared to the control group (p<0.05). A similar profile for the absorbance values was noted among the groups: 10 mg/mL presented an increase in viability compared to the control group. On the other hand, smaller concentrations presented a similar or lower viability compared to the control group, in general. A new dental material composed of calcium silicate-based cement with 20% zirconium oxide as the radiopacifier showed low cytotoxicity as a promising material to be exploited for root-end filling.

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.

Análise físico-química do MTA e do cimento Portland associado a quatro diferentes radiopacificadores

INTRODUÇÃO: O Mineral Trióxido Agregado (MTA) é composto por cimento Portland (CP) e um radiopacificador (óxido de bismuto).OBJETIVO: Avaliar tempo de presa, solubilidade, pH, liberação de íons Cálcio e radiopacidade do cimento Portland puro ou associado a quatro radiopacificadores (sulfato de bário, carbonato de bismuto, óxido de bismuto e iodofórmio), comparados ao MTA branco (Angelus, Londrina, Brasil).MATERIAL E MÉTODO: A proporção empregada CP/radiopacificador foi de 4:1 em peso, (80% de cimento Portland e 20% de radiopacificador). A especificação 57 da ADA foi usada para avaliação do tempo de presa. A solubilidade foi analisada segundo a especificação ISO 6876/2001. A avaliação do pH foi realizada com peagâmetro digital e a liberação de íons Ca++foi verificada por meio de espectrofotômetro de absorção atômica. A radiopacidade foi determinada em milímetros de alumínio (mm/Al). Os resultados foram submetidos aos testes de Análise de Variância e Tukey, nível de significância 5%.RESULTADO: O sulfato de bário não alterou o tempo de presa final do CP. Radiopacidade inferior ao mínimo recomendado pelas normas da ADA nº 57 e ISO 6876/2001 foi observada para CP e CP associado com sulfato de bário. O CP associado ao iodofórmio apresentou solubilidade acima dos 3% recomendados pela ISO 6876/2001. Todos os materiais proporcionaram alcalinização do meio e promoveram liberação de íons cálcio.CONCLUSÃO: Carbonato de bismuto ou óxido de bismuto proporcionaram tempo de presa inicial, solubilidade, pH, liberação de íons Cálcio e radiopacidade adequados quando associados ao CP.

Assessment of Color Stability of White Mineral Trioxide Aggregate Angelus and Bismuth Oxide in Contact with Tooth Structure

IntroductionDental discoloration with use of materials containing bismuth oxide has been reported. It is postulated that the discoloration is a result of chemical interaction of bismuth oxide with dentin. The aim of the study was to analyze dental color alteration and the chemical interaction of bismuth oxide with the main components present in composite (methacrylate) and in dentin (collagen). MethodsFifty bovine teeth were prepared and filled with white mineral trioxide aggregate (MTA) Angelus, Portland cement (PC) with 20% zirconium oxide, or PC with 20% calcium tungstate and then sealed with composite. Triple antibiotic paste and unfilled samples were the positive and negative controls, respectively. The specimens were stored in separate flasks immersed in tap water at 37°C with ambient light blocked out. The color assessment was performed with a spectrophotometer at different intervals, namely before filling and 24 hours, 15 days, and 30 days after filling. The color change and the luminosity were calculated. The statistical analysis was performed by using nonparametric Kruskal-Wallis and Dunn tests (P < .05). The interaction of the bismuth oxide, zirconium oxide, and calcium tungstate with collagen and methacrylate was assessed by placing the materials in contact, followed by color assessment. ResultsThe analysis of color change values showed that all the materials presented color alteration after the evaluated periods. Statistically higher luminosity was verified for PC/20% zirconium oxide in comparison with white MTA Angelus (P < .05). The teeth filled with white MTA Angelus demonstrated a grayish discoloration with evident dentin staining. Bismuth oxide exhibited a color change when in contact with collagen. ConclusionsThe color of white MTA Angelus was altered in contact with dental structures. Collagen, which is present in dentin matrix, reacted with bismuth oxide, resulting in a grayish discoloration. The use of an alternative radiopacifier to replace bismuth in white MTA is indicated.

Subcutaneous connective tissue reactions to iRoot SP, mineral trioxide aggregate (MTA) Fillapex, DiaRoot BioAggregate and MTA.

To evaluate connective tissue reactions to iRoot SP (Innovative Bioceramics, Vancouver, BC, Canada), mineral trioxide aggregate (MTA) Fillapex (FLPX) (Angelus Soluções Odontológicas, Londrina, Brazil), DiaRoot Bioaggregate (DiaDent Group International, Burnaby, BC, Canada) and white MTA (Angelus, Londrina, Brazil) in Wistar rats. A total of 128 dentine tubes filled with the materials and 32 empty tubes (control) were implanted into 32 rats. After 7, 15, 30 and 90 days (n = 8 per period), the animals were euthanized, and the tissues were processed for histological evaluation using haematoxylin-eosin (H&E) and Von Kossa (VK) staining. Observations were made for cellular inflammatory components and the presence of multinucleated giant cells (MNGC), macrophages and tissue necrosis. Data were analysed by Fisher's exact and Kruskal–Wallis tests (P < 0.05). In all experimental periods, MTA FLPX and iRoot SP scored higher than the other groups for the variable macrophages (P < 0.05). After 30- and 90-day experimental periods, MTA FLPX scored higher than the other groups for the variable MNGC (P < 0.05). After 90 days, the only group that exhibited samples with severe inflammatory response was MTA FLPX. VK positivity was observed in areas of necrosis in all groups, except in the control group. The materials were considered biologically acceptable except MTA FLPX, which remained toxic to subcutaneous tissue even after 90 days.

Effect of Various Mixing and Placement Techniques on the Flexural Strength and Porosity of Mineral Trioxide Aggregate

IntroductionThe aim of this study was to evaluate the effect of mechanical and manual mixing as well as the effect of ultrasonic agitation during placement on the flexural strength and porosity of mineral trioxide aggregate (MTA). MethodsWhite ProRoot MTA and white MTA Angelus were used. One gram of each powder was mixed with a 0.34-g aliquot of distilled water. Specimens were mixed either by mechanical mixing of capsules for 30 seconds at 4500 rpm or by a saturation technique and application of a condensation pressure of 3.22 MPa for 1 minute. The mixed slurries of all materials were loaded into 2 × 2 × 25 mm molds for testing flexural strength and 3 × 4 mm molds for evaluation of porosity. Half of the specimens were placed in the stainless steel molds by using indirect ultrasonic activation. All specimens were incubated for 4 days. Micro–computed tomography was used to determine the porosity of each specimen, and a 3-point bending test was used to evaluate flexural strength. Tukey honestly significant difference and independent t tests were carried out to compare the means at a significance level of P < .05. ResultsIrrespective of mixing and placement techniques applied, the flexural strength values of ProRoot MTA were significantly greater than those of MTA Angelus (P < .05). A medium negative correlation was found between flexural strength values and total porosity percentage. ConclusionsAlthough mechanical mixing of encapsulated cements was quicker and provided more consistent mixes, this technique along with ultrasonic agitation was not associated with a significant advantage in terms of flexural strength and total porosity over manual mixing.

Ability of different methods to fill retrograde cavities with MTA

The Mineral Trioxide Aggregate (MTA) has excellent biological property. However, its consistency makes it difficult to be inserted into retrograde cavities. Objective: To evaluate the ability of different methods to fill retrograde cavities with MTA. Material and methods: Root canals of thirty single-rooted resin teeth were prepared and filled. After the cut of 3 mm short of apical third, retrograde cavities with 3 mm deep were prepared using an ultrasound device and retrotips (CVD, São José dos Campos, SP, Brazil). The retrograde preparation was evaluate by using an operative microscope (D.F. Vasconcellos, São Paulo, SP, Brazil). The teeth were randomly divided into three groups (n = 10), according to the method: 1) condenser (Trinity, São Paulo, SP, Brazil); 2) MTA applicator (Angelus, Londrina, Brazil) + condenser; 3) condenser associated with ultrasound (CVD, São José dos Campos, SP, Brazil). After the filling of retrograde cavities with white MTA (Angelus, Londrina, Brazil), teeth were radiographed using a digital system (Kodak RVG 6000, Rochester, NY, USA). The images were analyzed by UTHSCSA Image Tool 3.0 software. The percentage of filling was calculated by the proportion between the total area of retrograde cavity and the filled area. The radiographic density mean of each third of retrograde cavity filled with MTA was measured by using the histogram tool of the software. The results were submitted to ANOVA and Tukey tests, with 5% of significance. Results: There was no difference in percentage of filling among the groups (p &gt; 0.05) (approximately 85%). By comparing the thirds, the condenser and MTA applicator groups showed higher density for apical and middle third than cervical third (p &lt; 0.05). The ultrasound group presented similar density among the thirds. Conclusion: The filling ability was similar for the studied methods. Ultrasound promoted better distribution of MTA in retrograde cavity, but did not increase the density of material.

Evaluation of pH and Calcium Ion Release of a Dual-cure Bisphenol A Ethoxylate Dimethacrylate/Mineral Trioxide Aggregate–based Root-end Filling Material

IntroductionThe incorporation of light-curable resins has been proposed for mineral trioxide aggregate (MTA) to improve its properties and reduce its setting time. The aim of the present study was to assess the pH and calcium ion release of an experimental bisphenol A ethoxylate dimethacrylate/MTA-based root-end filling material (E-MTA) in comparison with white MTA Angelus (Angelus, Londrina, PR, Brazil) (W-MTA) and to evaluate the influence of the addition of calcium chloride (CaCl2) on these properties. MethodsPolyethylene tubes filled with the materials were immersed in deionized water for the measurement of pH (digital pH meter) and calcium release (atomic absorption spectrophotometry). The evaluations were performed at 3 and 24 hours and 7, 15, and 30 days. Data were measured using 2-way repeated measures of variance followed by the Holm-Sidak method (P < .05). ResultsAll materials presented a reduction in the pH and released calcium ions during the 30 days of the study. E-MTA showed a significantly lower calcium ion release capacity when compared with W-MTA (P < .05). The calcium release of E-MTA + 5% CaCl2 was similar to W-MTA (P > .05). ConclusionsThe monomer bisphenol A ethoxylate dimethacrylate added to MTA formed a material with a lower capacity of calcium release than W-MTA despite maintaining a similar pH. However, the addition of CaCl2 improved the calcium release of this material.

Effect of bismuth oxide on white mineral trioxide aggregate: chemical characterization and physical properties

To assess the effect of bismuth oxide (Bi2 O3 ) on the chemical characterization and physical properties of White mineral trioxide aggregate (MTA) Angelus. Commercially available White MTA Angelus and White MTA Angelus without Bi2 O3 provided by the manufacturer especially for this study were subjected to the following tests: Rietveld X-ray diffraction analysis (XRD), energy-dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), compressive strength, Vickers microhardness test and setting time. Chemical analysis data were reported descriptively, and physical properties were expressed as means and standard deviations. Data were analysed using Student's t-test and Mann-Whitney U test (P = 0.05). Calcium silicate peaks were reduced in the diffractograms of both hydrated materials. Bismuth particles were found on the surface of White MTA Angelus, and a greater amount of particles characterized as calcium hydroxide was observed by visual examination on White MTA without Bi2 O3 . The material without Bi2 O3 had the shortest final setting time (38.33 min, P = 0.002), the highest Vickers microhardness mean value (72.35 MPa, P = 0.000) and similar compressive strength results (P = 0.329) when compared with the commercially available White MTA Angelus containing Bi2 O3 . The lack of Bi2 O3 was associated with an increase in Vickers microhardness, a reduction in final setting time, absence of Bi2 O3 peaks in diffractograms, as well as a large amount of calcium and a morphology characteristic of calcium hydroxide in EDX/SEM analysis.