Chemical modification of MTA and CEM cement to decrease setting time and improve bioactivity properties by adding alkaline salts.
ABSTRACT: Background. Mineral trioxide aggregate (MTA) and Calcium-enriched Mixture (CEM) cement are used for pulp capping since they induce the formation of a dentinal bridge. Long setting time is a shortcoming of these types of cement. This study aimed to assess the effect of the incorporation of some alkaline salts to MTA and CEM cement on their setting time, ion release profile, pH, and surface morphology. Methods. In this in vitro experimental study, 5% calcium chloride (CaCl2), calcium oxide (CaO), sodium fluoride (NaF), and calcium nitrate [Ca(NO3)2] were separately added to MTA and CEM cement. The primary and final setting times of the cements were measured using a Gillmore needle apparatus. The samples were immersed in simulated body fluid (SBF) for one, seven, and 14 days and subjected to x-ray diffraction (XRD) and scanning electron microscopy (SEM) for phase identification and surface morphology assessment. The change in the pH of solutions was studied, and the calcium ion release profile was determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES). The data were analyzed with ANOVA, followed by post hoc tests. Results. CaCl2 and CaO decreased the setting time of MTA, and Ca(NO3)2 decreased the setting time of CEM cement. The incorporation of the salts increased the pH and calcium ion release from both cements, and hydroxyapatite deposits were noted to cover the surface of the samples (observed by SEM and confirmed by EDXA). Conclusion. The incorporation of CaCl2 and CaO into MTA and Ca(NO3)2 into CEM cement decreased their setting time and increased their pH and calcium ion release.
Project description:This in vitro study investigated the effect of adding 10% calcium chloride (CaCl2) on push out bond strength of calcium-enriched mixture (CEM) cement and mineral trioxide aggregate (MTA) to root canal dentin.A total of 120 root dentin slices with 2 mm thickness were prepared from sixty single-rooted human teeth. Dentinal discs were enlarged to achieve 1.3 mm diameter. The specimens were randomly allocated into eight groups (n=15). Dentin discs were filled with either CEM cement or MTA with or without CaCl2 and the push out test was performed after 3 and 21 days. Data were analyzed with two-way ANOVA test. The level of significance was set at 0.05.There was an interaction effect amongst all groups (P=0.028). After 3 days, CEM cement showed a significantly lower bond strength than other groups (P<0.05) while MTA demonstrated significantly higher bond strength than CEM cement with or without CaCl2 (P=0.001). After 21 days, CEM cement with or without CaCl2 had no significant difference with other groups (P>0.05). However, the bond strength of MTA decreased when CaCl2 was added (P=0.011).The addition of 10% CaCl2 increased the push out bond strength of CEM cement and improved it over time; while, this substance aggravated this property for MTA.
Project description:Propylene glycol (PG) improves the handling, physical, and chemical properties of mineral trioxide aggregate (MTA). This study aimed to evaluate the effect of PG on the sealing ability of MTA and calcium-enriched mixture (CEM) apical barriers.A total of 70 extracted human maxillary single-rooted teeth were prepared using ProTaper rotary system. The apical 3 mm of the root tips were resected and the root canals were enlarged with Peeso reamers up to #4, to create open apex teeth. The teeth were then randomly divided into four experimental (n=15) and two control (n=5) groups. Group1: MTA+ MTA liquid, group2; MTA+MTA liquid (80%) + PG (20%), group3; CEM+CEM liquid, group4; CEM+ liquid (80%) + PG (20%). Cements were mixed with their respective mixing agents and a 4-mm thick apical plug was fabricated. The microleakage was measured on day 1, 3, 7 and 21 using a fluid filtration technique. The repeated measures ANOVA and Sidak test were used to analyze the data.All experimental groups demonstrated various amounts of microleakage. No significant difference was found between MTA and CEM cement (P=0.193), regardless of time and liquid components. There was no significant difference was observed between liquids (P=0.312) in all time intervals. The rate of microleakage decreased over time and a significant differences was observed between all intervals (P<0.05), except 3-7 and 7-21 (P=0.190) days.PG demonstrated neither a positive nor a negative effect on the sealing ability of Angelus MTA and CEM cement.
Project description:Broken instruments in root canals complicate routine endodontic treatment. This study aimed to compare apical microleakage in root canals containing broken rotary instruments filled with mineral trioxide aggregate (MTA), calcium-enriched mixture (CEM) cement, laterally compacted gutta-percha and injected gutta-percha.In this in vitro, experimental study, 80 extracted human premolars were decoronated and then the roots were randomly divided into four groups (n=20). Root canals were instrumented with Mtwo rotary files. The files were scratched 3 mm from the tip by a high speed handpiece and they were intentionally broken in the apical third of the canals. The middle and coronal thirds of the canals were then filled with MTA, CEM cement, gutta-percha with lateral compaction technique and injected gutta-percha. Apical microleakage was measured using dye penetration method. Data were analyzed using ANOVA and Tukey's test.Root canals filled with CEM cement showed the lowest and those filled with injected gutta-percha showed the highest microleakage according to dye penetration depth. No significant difference was noted between the microleakage of CEM cement and MTA or between lateral compaction of gutta-percha and injected gutta-percha (P>0.05). However, CEM cement and MTA groups had significantly lower microleakage than laterally compacted and injected gutta-percha groups (P<0.05).Due to their superior sealing ability, MTA and CEM cement are suitable for filling of root canals containing a broken instrument compared to laterally compacted and injected gutta-percha.
Project description:Calcium phosphate cements are of great interest for researchers and their applications in medical practice expanded. Nevertheless, they have a number of drawbacks including the insufficient level of mechanical properties and low degradation rate. Struvite (MgNH4PO4) -based cements, which grew in popularity in recent years, despite their neutral pH and acceptable mechanical performance, release undesirable NH4 + ions during their resorption. This issue could be avoided by replacement of ammonia ions in the cement liquid with sodium, however, such cements have a pH values of 9-10, leading to cytotoxicity. Thus, the main goal of this investigation is to optimize the composition of cements to achieve the combination of desirable properties: neutral pH, sufficient mechanical properties, and the absence of cytotoxicity, applying Na2HPO4-based cement liquid. For this purpose, cement powders precursors in the CaO-MgO-P2O5 system were synthesized by one-pot process in a wide composition range, and their properties were investigated. The optimal performance was observed for the cements with (Ca + Mg)/P ratio of 1.67, which are characterized by newberyite phase formation during setting reaction, pH values close to 7, sufficient compressive strength up to 22 ± 3 MPa (for 20 mol.% of Mg), dense microstructure and adequate matrix properties of the surface. This set of features make those materials promising candidates for medical applications.
Project description:This case report presents the successful surgical treatment of a symptomatic open apex upper central incisor with a failed overfilled mineral trioxide aggregate (MTA) apical plug. Unintentional overextension of the MTA had occurred two years before the initial visit. An apical lesion adjacent to the excess MTA was radiographically detectable. Endodontic surgery was performed using calcium-enriched mixture (CEM) cement as a root-end filling material. Curettage of the apical lesion showed a mass of unset MTA particles; histopathological examination revealed fragments of MTA and granulation tissues. Up to 18-month follow-up, the tooth was clinically asymptomatic and fully functional. Periapical radiograph and CBCT images showed a normal periodontal ligament around the root. In conclusion, favorable outcomes in this case study suggested that root-end filling with CEM cement might be an appropriate approach; in addition, however many factors probably related to the initial failure of the case, the extrusion of MTA into the periapical area should be avoided.
Project description:Addition of zinc oxide (ZnO) to Mineral Trioxide Aggregate (MTA) has been shown to rectify tooth discoloration caused by Angelus MTA. This study evaluated the microhardness, compressive strength, calcium ion release and crystalline structures of MTA mixed with ZnO in different environmental conditions. Molds with a diameter of 4 mm and a height of 6 mm were used for compressive strength, calcium ion release and X-ray diffraction (XRD) evaluations. Molds with 6 mm diameter and 4 mm height were used for surface microhardness evaluations. Cements evaluated include Angelus MTA (Angelus, Brail), Angelus MTA + ZnO, ProRoot MTA (Dentsply Tulsa Dental, OK), and ProRoot MTA + ZnO. Each group was divided into 3 subgroups according to exposure conditions: normal saline (NS), phosphate buffered saline (PBS) or blood. After 7 days incubation, surface microhardness, compressive strength and XRD analysis was performed. Calcium ion release was evaluated after 3, 24 and 168h incubation using atomic absorption spectrophotometry. Data were analyzed by One Way Anova followed by the Tukey HSD Post hoc tests and T-Test. The significance level was set at 0.05. Addition of ZnO to Angelus and ProRoot MTA significantly decreased the compressive strength of these cements regardless of the environmental conditions (P < 0.001); however, it had no significant effect on their microhardness or calcium ion release. In conclusion, adding ZnO to Angelus and ProRoot MTA can adversely affect the compressive strength of Angelus and ProRoot MTA.
Project description:The aim of this in vitro study was to determine the liquid-powder ratio, setting time, solubility, dimensional change, pH, and radiopacity of white structural and non-structural Portland cement, ProRoot MTA and MTA Bio, associated with a 2% glycolic solution containing Aloe Vera, as vehicle.Five samples of each material were used for each test, according to the American National Standards Institute/American Dental Association (ANSI/ADA) specification No. 57. Statistical analyses were performed using ANOVA and Tukey's test at 5% significance. When sample distribution was not normal, non-parametric analysis of variance and the Kruskal-Wallis test were used (α=0.05).No statistical differences were found in liquid-powder ratios among the tested materials. ProRoot MTA showed the longest setting time. Dimensional change values were acceptable in all groups. Also, no significant differences were found in pH values and pH was alkaline in all samples throughout the experiment. Mean radiopacity results obtained for white Portland cements did not meet ANSI/ADA requirements, and were significantly lower than those obtained for MTA-based cements. Finally, Portland cements showed significantly higher mean solubility values compared to the other samples.The physicochemical properties of the tested materials in association with Aloe Vera were compatible with ANSI/ADA requirements, except for the white Portland cements, which failed to meet the radiopacity specification.
Project description:A newly-isolated Lysinibacillus sp. strain WH could precipitate CaCO3 using calcium acetate (Ca(C2H3O2)2), calcium chloride (CaCl2) and calcium nitrate (Ca(NO3)2) via non-ureolytic processes. We developed an algorithm to determine CaCO3 crystal structures by fitting the simulated XRD spectra to the experimental data using the artificial neural networks (ANNs). The biogenic CaCO3 crystals when using CaCl2 and Ca(NO3)2 are trigonal calcites with space group R3c, while those when using Ca(C2H3O2)2 are hexagonal vaterites with space group P6522. Their elastic properties are derived from the Voigt–Reuss–Hill (VRH) approximation. The bulk, Young's, and shear moduli of biogenic calcite are 77.812, 88.197, and 33.645 GPa, respectively, while those of vaterite are 67.082, 68.644, 25.818 GPa, respectively. Their Poisson’s ratios are ~?0.3–0.33, suggesting the ductility behavior of our crystals. These elastic values are comparable to those found in limestone cement, but are significantly larger than those of Portland cement. Based on the biocement experiment, the maximum increase in the compressive strength of Portland cement (27.4%) was found when Ca(NO3)2 was used. An increased strength of 26.1% was also found when Ca(C2H3O2)2 was used, implying the transformation of less-durable vaterite to higher-durable calcite. CaCO3 produced by strain WH has a potential to strengthen Portland cement-based materials.
Project description:Objective:This study evaluated the bioactivity and physicochemical properties of three commercial calcium silicate-based endodontic materials (MTA, EndoSequence Root Repair Material putty, and Biodentine™). Material and Methods. Horizontal sections of 3?mm thickness from 18 root canals of human teeth were subjected to biomechanical preparation with WaveOne Gold large rotary instruments. The twelve specimens were filled with three tested materials (MM-MTA, EndoSequence Root Repair Material putty, and Biodentine™) and immersed in phosphate-buffered saline for 7 and 30 days. After this period of time, each specimen of each material was processed for morphological observation, surface precipitates, and interfacial dentin using SEM. In addition, the surface morphology of the set materials, without soaking in phosphate-buffered solution after one day and after 28 days stored in phosphate-buffered saline, was evaluated using SEM; also, the pH of the soaking water and the amount of calcium ions released from the test materials were measured by using an inductively coupled plasma-optical emission spectroscopy test. Data obtained were analyzed using one-way analysis of variance and Tukey's honest significant difference test with a significance level of 5%. Result:The formation of precipitates was observed on the surfaces of all materials at 1 week and increased substantially over time. Interfacial layers in some areas of the dentin-cement interface were found from one week of immersion. All the analyzed materials showed alkaline pH and capacity to release calcium ions; however, the concentrations of released calcium ions were significantly more in Biodentine and ESRRM putty than MM-MTA (P < 0.05). ESRRM putty maintained a pH of around 11 after 28 days. Conclusion:Compared with MM-MTA, Biodentine and ESRRM putty showed significantly more calcium ion release. However, exposure of three tested cements to phosphate-buffered solution resulted in precipitation of apatite crystalline structures over both cement and dentin that increased over time. This suggests that the tested materials are bioactive.
Project description:Background. Stem cell-based treatment modalities have been potential strategies for tissue regeneration in many conditions. Several studies have evaluated the biologic properties of DPSCs and their efficacy in the treatment of a variety of diseases. The present study was undertaken to evaluate the adhesion behavior of DPSCs on different endodontic materials before and after setting. Methods. The crowns of the selected teeth were removed, and the root canals were prepared and obturated with gutta-percha and AH26 sealer. A retrograde cavity was prepared at root ends. Different materials were placed in the cavities. Then the samples were attached to the wells with the use of a chemical glue. Dental pulp stem cells were allowed to proliferate to reach a count of 2 million and transferred to -12well plates in association with a culture medium. Finally, the samples attached to the wells were exposed to the stem cells immersed in the culture medium before and after setting. Then adhesion of the stem cells was evaluated using SEM. Results. The SEM results showed cellular adhesion in the samples containing CEM cement both before and after setting. The samples containing MTA Angelus and ProRoot MTA exhibited cellular adhesion before setting, with no cellular adhesion after setting. The samples containing AH26 and MTA Fillapex sealers exhibited cellular adhesion after setting, with no adhesion before setting. The samples containing simvastatin exhibited no cellular adhesion before setting; this material had dissolved in the culture medium after setting evaluation. Conclusion. The results of the present study showed that of all the materials tested, CEM cement had the highest capacity for dental pulp stem cell adhesion.