A comparative study of selected properties of ProRoot mineral trioxide aggregate and two Portland cements

Effect of Fluorohydroxyapatite on Biological and Physical Properties of MTA Angelus

Objectives

This study aimed to assess the effect of addition of fluorohydroxyapatite (FHI) on biological and physical properties of mineral trioxide aggregate (MTA) Angelus.

Materials and Methods

In this in vitro, experimental study, nano-FHI powder was first synthesized, and the morphology and chemical structure of particles were evaluated by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Three groups were evaluated in this study: MTA Angelus, MTA modified with 10% FHA, and MTA modified with 15% FHA. After mixing, the materials were applied to ring molds (10 mm diameter, 1 mm height), and the setting time of the three groups was evaluated according to ISO6876 and ASTMC266-03 with a Gillmore needle. The pH was measured using a pH meter at 24 and 48 hours and 7 days after mixing. The cytotoxicity of the materials was assessed in freshly mixed form and after 1 and 7 days using the methyl thiazolyl tetrazolium (MTT) assay according to ISO10993-5. Data were analyzed by one-way and repeated measures ANOVA and Tukey's test (alpha = 0.05).

Results

The addition of FHA to MTA significantly decreased the initial setting time (P < 0.05) and had no significant effect on cell viability (compared with pure MTA Angelus) at 1 and 7 days. However, modified MTA groups in freshly mixed form showed significantly lower cell viability (P < 0.05). The pH remained alkaline at all time points.

Conclusion

Addition of 15% FHA to MTA Angelus decreased its setting time with no adverse effect on cell viability (except for fresh form) or pH.

Effect of Different Mixing Methods on Physicochemical Properties of Mineral Trioxide Aggregate: A Systematic Review

Background

Mineral trioxide aggregate (MTA) is a commonly used endodontic biomaterial. The physicochemical properties of MTA have a crucial role in designating clinical outcome, and different factors can affect these properties. Various methods have been used for mixing MTA, including manual, mechanical, and ultrasonic. The aim of this systematic review was to evaluate the effect of different mixing methods on the physicochemical properties of MTA.

Materials and Methods

Electronic databases including PubMed, Embase, Web of Science, and Scopus were searched up to May 2022. In order to cover gray literature, the ProQuest and Google Scholar databases were also searched to detect theses and conference proceedings. For quality assessment of the included studies, we used a modified version of the Cochrane risk of bias tool for randomized controlled trials (RCTs). Experimental studies which had assessed at least one property of MTA and compared at least two different mixing methods of MTA were included in this study. All animal studies, reviews, case reports, and case series were excluded.

Results

Fourteen studies were included. The results showed that the ultrasonic mixing method significantly improved some MTA characteristics, including microhardness, flowability, solubility, setting time, and porosity. However, the mechanical mixing method improved other properties including flowability, solubility, push-out bond strength, and hydration. The manual mixing method showed inferior results compared to other mixing methods in terms of microhardness, flowability, solubility, setting time, push-out bond strength, porosity, and hydration. Different mixing methods had a similar effect on compressive strength, sealing ability, pH and calcium ion release, volume change, film thickness, and flexural strength of MTA.

Conclusion

Mechanical and ultrasonic mixing methods are superior to the manual mixing method in terms of improving physicochemical properties of MTA. No report of selection bias and varieties in methodologies were limitations of evidence.

Effects of a mineralization-promoting peptide on the physical and chemical properties of mineral trioxide aggregate

Mineral trioxide aggregate (MTA) has been used widely in dentistry due to its sealing ability and biocompatibility. Delayed setting time is one of the major limitations of MTA. Various additives have been studied to further improve the properties of MTA with varied degrees of success. In this study, we have investigated the effect of a calcium phosphate mineralization promoting-peptide (MPP3) on the physical and chemical properties of MTA in comparison with Na₂HPO₄. Based on the reported effects of MPP3 on calcium-phosphate mineralization reaction, our hypothesis was that MPP3 may also show beneficial effects on the calcium-silicate mineralization system of MTA. Na₂HPO₄ was used for comparison since its setting accelerant effect on MTA has been well documented. The cements were prepared by mixing with distilled water, 0.40 mM MPP3 solution, 15% Na₂HPO₄ solution, and a combination of MPP3 and Na₂HPO₄ solution. Initial and final setting times were measured via Vicat needle. Microhardness values were measured via Vickers indenter at 1,3,7, and 28 days after hydration. Compressive strength after setting was measured via universal testing machine. Morphological and compositional analyses were performed via FESEM imaging, XRD and Raman spectroscopy. The microhardness data was evaluated via repeated-measures ANOVA. Setting time and compressive strength data were evasluated via one-way ANOVA. Initial setting time was reduced to ∼3 min in the Na₂HPO₄ containing groups but remained at ∼5 min in the control and MPP3 groups. Final setting times were significantly reduced in all groups compared to the control group. The reduction in the final setting times in the Na₂HPO₄ containing groups were significantly higher compared to the MPP3 group. Microhardness was significantly higher in the MPP3 group at all time points. No statistically significant difference in compressive strength was observed among the groups. FESEM analysis showed presence of ettringite crystals in the MPP3 group, and NaBiO₃ crystals in the Na₂HPO₄ containing groups. XRD analysis showed a broadening of peaks at 2θ = 32° in the Na₂HPO₄ containing groups, possibly due to presence of NaBiO₃. Raman spectroscopy showed statistically higher ettringite content in the MPP3 containing groups. Our findings indicate that MPP3 is a beneficial additive to eliminate some of the drawbacks associated with MTA with no detrimental effects on mechanical properties and without resulting in phases that potentially cause discoloration, such as NaBiO₃. We propose that the reduced final setting time and increased microhardness by MPP3 may be associated with the increased ettringite content. Future studies, where wider range of MPP3 concentrations are studied may help elucidate and optimize the beneficial effects of MPP3 observed in this study.

Fracture Resistance of Molars With Simulated Strip Perforation Repaired With Different Calcium Silicate-Based Cements

Background and aims A root perforation is a connection between the root canal system and the external supportive tissues. Strip perforation (SP), occurring within root canals in a strip, can worsen the prognosis of a treated tooth, reduce its mechanical resistance, and impair the tooth structure. One of the suggested methods to treat SP is to seal it with a bio-material such as calcium silicate cement. Therefore, this in vitro study aimed to assess the molar structure impairment due to SP, which requires studying the fracture resistance, and the ability of mineral trioxide aggregate (MTA), bioceramic, and calcium-enriched mixture (CEM) to repair this perforation. Materials and methods Seventy-five molars were instrumented to size #25 and taper 4%, irrigated with sodium hypochlorite and ethylenediaminetetraacetic acid (EDTA), dried, and then divided randomly into five groups (G1-G5): in G1, root canals were filled with gutta-percha and sealer (negative control sample), whereas the rest of the groups (G2-G5) had a manual simulated SP made with Gates Glidden drill at the mesial root of the extracted molar, and filled with gutta-percha and sealer up to their perforation area; in G2, SP was filled with gutta-percha and sealer (positive control sample); G3 used MTA to repair the SP; G4 used bioceramic putty; and G5 used CEM. Fracture resistance tests of the molars were conducted in the crown-apical direction using a universal testing machine. One-way ANOVA test and Bonferroni test were used to study the significance of the differences in the mean values of the tooth fracture resistance, where statistical significance was set at 0.05. Results The ANOVA test showed that there were statistically significant differences between the fracture resistance (in newtons) values among groups (p = 0.000). The Bonferroni test showed that G2 had a smaller fracture resistance mean than the other four study groups (656.53 N; p = 0.000), and that of G5 was smaller than G1, G3, and G4 (794.40 N, 1083.73 N, 1025.20 N, and 1034.20 N, respectively; p = 0.000 in each pairwise comparison). Conclusion SP reduced the fracture resistance of endodontically treated molars. SP restored using MTA and bioceramic putty was better than that treated with CEM and similar to molars without SP. Moreover, MTA and bioceramic putty enhanced the fracture resistance of endodontically treated teeth to levels similar to molars without SP.

Methods for testing solubility of hydraulic calcium silicate cements for root-end filling

Regulatory testing of hydraulic cements used in dentistry and standard test methods for root-end filling materials do not exist. The aim of this study was to identify a simple, reproducible method for testing the solubility of materials that set with water (hydraulic) used as root-end filling materials in dentistry. Commercial and prototype hydraulic cements were characterized by scanning electron microscopy and X-ray diffraction analyses and their solubilities were determined using ISO 6876; 2012 standard, a modified ISO 6876 method with media alternative to water and a new method measuring the percentage mass loss and volume change of materials (micro-CT method) from a single surface exposed to three solutions. The solubility testing was performed by three operators to enable an intra-laboratory comparison. The solubility data obtained from the two commercial and two prototype materials varied depending on the method used, with the ISO 6876 method identifying differences in solubility of the materials (p < 0.05) but when modified with alternative solutions, no differences were found (p > 0.05). The changes in solution thus effected the solubility of the tested materials. Inter-operator differences were observed with the weight changes determined from the new method indicating this method was not robust. The weight and volume assessments using the new method were not solution-dependent. The advantage of the proposed method compared with the ISO standard is its simplicity, enabling a number of tests to be performed on the same set of samples that also more closely mimics the clinical environment.

Portland Cement: An Overview as a Root Repair Material

Portland cement (PC) is used in challenging endodontic situations in which preserving the health and functionality of pulp tissue is of considerable importance. PC forms the main component of mineral trioxide aggregate (MTA) and demonstrates similar desirable properties as an orthograde or retrograde filling material. PC is able to protect pulp against bacterial infiltration, induce reparative dentinogenesis, and form dentin bridge during the pulp healing process. The biocompatibility, bioactivity, and physical properties of PC have been investigated in vitro and in animal models, as well as in some limited clinical trials. This paper reviews Portland cement's structure and its characteristics and reaction in various environments and eventually accentuates the present concerns with this material. This bioactive endodontic cement has shown promising success rates compared to MTA; however, considerable modifications are required in order to improve its characteristics and expand its application scope as a root repair material. Hence, the extensive chemical modifications incorporated into PC composition to facilitate preparation and handling procedures are discussed. It is still important to further address the applicability, reliability, and cost-effectiveness of PC before transferring into day-to-day clinical practice.

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

BACKGROUND/PURPOSE

MTA 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 METHODS

Human 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).

RESULTS

MTA-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.

CONCLUSION

The addition of more than 5% CaF2 can be considered to increase the regeneration potential of pulp cells without adverse effects on physical property.

Solubility of Calcium Silicate Based Cements – a Comparative Study

Calcium silicate based cement is a group of biomaterials, based on Portland cement. Its physicochemical properties such as solubility are of the utmost importance. It should have low solubility in tissue fluid since the dissolution of materials may lead to treatment failure.

The aim of this study is to evaluate the solubility of five calcium silicate cements after being placed in distilled water for a period of 28 days.

Material and methods: The purpose of this study was to compare solubility of a four new calcium silicate-based cements, such as: gray MTA Angelus; white MTA Angelus; BioAggregate and Biodentine with conventional mineral trioxide aggregate White ProRoot. Solubility is evaluated using standardized samples of materials, which are weighed before and after 28-day immersion in distilled water.

Results: The lowest solubility is found at White ProRoot and the significantly highest solubility – at Biodentine.

Effect of Er:YAG laser etching on topography, microstructure, compressive strength, and bond strength of a universal adhesive to calcium silicate cements

OBJECTIVE

To evaluate the effect of Er:YAG etching on topography, microstructure, compressive strength, and shear bond strength (SBS) of All-Bond Universal adhesive to mineral trioxide aggregate-Angelus (AMTA) and Biodentine (BD).

METHODS AND MATERIALS

Sixty cylindrical specimens of each cement (AMTA and BD) in five groups were prepared and stored for 72 h. The control groups were non-etched, and four other groups were acid-etched and laser-etched with a pulse energy of 60, 80, or 100 mJ, followed by compressive strength testing. Surface micromorphology and topography were evaluated. Similar groups were bonded using All-Bond Universal with self-etch and etch-and-rinse (acid-etch) approaches, and laser-etch 60, 80, and 100 mJ, and SBS was tested. Data were analyzed using two-way and one-way ANOVA and the Bonferroni post hoc tests (α = 0.05).

RESULTS

BD had a significantly higher compressive strength and SBS (except for laser-etch 100) compared to AMTA, regardless of the etching method (p < 0.001). Acid etching and laser etching 100 of both cements and laser etching 80 of BD alone produced a significantly lower compressive strength than that for the other groups. Contrary to BD, for AMTA, all the treatments significantly increased SBS compared to that of the self-etch group.

CONCLUSIONS

Etching of AMTA was needed for stronger bonding; laser etching with 60 or 80 mJ without compromising compressive strength was recommended. Etching not only did not improve bonding ability of BD, but it also negatively affected the strength of BD.

CLINICAL RELEVANCE

To achieve successful combined calcium silicate cement-resin material restoration, an adequate bond between the materials is mandatory. This might be provided with the ultramild adhesive through laser etching without compromising compressive strength, depending on cement composition and laser energy level used.

Effect of reducing acid-etching duration time on compressive strength and bonding of a universal adhesive to calcium silicate cements

AIM

To assess the effect of acid-etching duration time on the compressive strength, microstructure and shear bond strength of All-Bond Universal adhesive to MTA-Angelus (AMTA), and Biodentine (BD).

METHODOLOGY

Forty-eight cylindrical specimens (4 mm in diameter, 6 mm in height) of AMTA in four groups and 48 specimens of BD in four groups (n = 12) were prepared and stored for 72 h. The control groups were unetched whilst the three experimental groups were acid-etched for 5, 10 and 15 s, respectively, followed by compressive strength testing. The effect of the various acid-etching times on surface micromorphology was evaluated under a scanning electron microscope. Similar groups were bonded using All-Bond Universal and Aelite Flo and shear bond strength was tested. Data were analysed using two-way ANOVA and Tukey tests.

RESULTS

10-s and 15-s acid-etching reduced the compressive strength of AMTA and BD (P < 0.001), while 5-s etching did not (P ≤ 0.86). In all the groups, BD had greater compressive strength compared to AMTA. Contrary to BD, the three etched AMTA groups had significantly higher shear bond strength compared to the control group (P < 0.001), with no significant differences between them. The etched groups of AMTA had shear bond strengths comparable to all the BD groups. Scanning electron microscope observations indicated variable surface morphologies such as remnant crystals and cracking/eroding in all our groups of AMTA; though these differences were less prominent for BD.

CONCLUSIONS

Shortening the acid-etching time to 5 s resulted in a beneficial effect in terms of resin bonding for AMTA while preventing the detrimental effect of 10-s and 15-s etching on the compressive strength of AMTA and BD. However, the three etching times had no effect on resin-BD bond.

Sintering Pmperature-Dependence on Radiopacity of Bi(2-x) ZrxO(3+x/2) Powders Prepared by Sol-Gel Process

Bismuth oxide (Bi₂O₃) is an effective additive used to enhance radiography resolution for dental materials. However, there are potential concerns regarding its biocompatibility and connection to tissue discoloration. In the present study, we modified the radiopacity properties of Bi₂O₃ with zirconium oxide (ZrO₂) using a sol-gel process and investigated the composition, as well as the effects of heat treatment temperature using Thermogravimetry analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The harvested Bi2-xZrxO3+x/2 particles showed that the dominant phase transferred from α-Bi₂O₃ to β-Bi7.38Zr0.62O12.31 after a heat treatment of over 750 °C for 2 h. As the x values of Bi2-xZrxO3+x/2 increased from 0.2 to 1.0, more zirconium oxide precipitated onto the particle surface, thus enhancing the surface roughness of particles. For sol-gel Bi1.8Zr0.2O3.1 powders (x = 0.2), the radiopacity values became 4.90 ± 0.23 and 5.83 ± 0.22 mmAl after a heat treatment of 500 °C and 750 °C, respectively.

Mineral trioxide aggregate affects cell viability and induces apoptosis of stem cells from human exfoliated deciduous teeth

BACKGROUND

Mineral trioxide aggregate (MTA) is widely used for pulp-capping procedures in permanent teeth and as a gold standard material in endodontics. The aim of the study was to investigate the effect of MTA on cell viability and apoptosis when MTA is directly in contact with Stem Cells from Human Exfoliated Deciduous Teeth (SHEDs).

METHODS

MTA was mixed and coated in the bottom of a 24-well plate. SHEDs collected and cultured from normal exfoliated human deciduous teeth (passages 3-4) were seeded on square cover glasses. The glasses with seeded SHEDs were incubated in the plates with or without MTA coating. They were divided into four groups: MTA direct contact, direct control, MTA indirect contact, and indirect control. After 1, 2 and 3 days of culturing, cell morphology was observed and cell viability was assessed by the WST-1 cell cytotoxicity assay. TUNEL assay, immunofluorescent labeling and western blot analysis were used to study the effects of MTA on SHEDs apoptosis.

RESULTS

MTA impaired cell viability of SHEDs in 1, 2 and 3 days, and the effect of direct contact was more severe. Cell apoptosis with positive Annexin V and TUNEL staining was noted when there was direct contact with MTA. Western blot analysis revealed that Bcl-2 and Bcl-xL decreased after SHEDs were in contact with MTA.

CONCLUSIONS

This study shows that direct contact with 1 week post-set MTA significantly decreases the viability of SHEDs and induced cell apoptosis. The results suggest that there is a possible cytotoxic effect of pulp tissue when there is direct contact with MTA. Different responses would be expected due to the strong alkaline characteristics of fresh mixed MTA.

Mineral Trioxide Aggregate-A Review of Properties and Testing Methodologies

Mineral trioxide aggregate (MTA) restoratives and MTA sealers are commonly used in endodontics. Commonly referenced standards for testing of MTA are ISO 6876, 9917-1 and 10993. A PubMed search was performed relating to the relevant tests within each ISO and "mineral trioxide aggregate". MTA restoratives are typically tested with a mixture of tests from multiple standards. As the setting of MTA is dependent upon hydration, the results of various MTA restoratives and sealers are dependent upon the curing methodology. This includes physical properties after mixing, physical properties after setting and biocompatibility. The tests of flow, film thickness, working time and setting time can be superseded by rheology as it details how MTA hydrates. Physical property tests should replicate physiological conditions, i.e. 37 °C and submerged in physiological solution. Biocompatibility tests should involve immediate placement of samples immediately after mixing rather than being cured prior to placement as this does not replicate clinical usage. Biocompatibility tests should seek to replicate physiological conditions with MTA tested immediately after mixing.

The Effect of Calcium Chloride on Push-Out Bond Strength of Calcium-Enriched Mixture Cement and Mineral Trioxide Aggregate

Introduction:

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.

Methods and Materials:

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.

Results:

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).

Conclusion:

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.

MTA versus Biodentine: Review of Literature with a Comparative Analysis

An ideal dental repair material should possess certain exclusive properties such as adequate adhesive ability, insolubility, dimensional stability, biocompatibility, bioactivity etc. New materials claiming better performance are continuously being introduced in the market to optimize the care of dental patients. Biodentine has been recently introduced as the "the first all-in-one, bioactive and biocompatible material for damaged dentin replacement". Manufacturers claim that Biodentine has noticeably shorter setting time in contrast to other silicate cements such as Mineral Trioxide Aggregate (MTA) and also has better mechanical and handling properties. This article is aimed to compare the properties of MTA and Biodentine analyzing the research work done in this field so far by various researchers all across the globe.

Calcium silicate-based cements and functional impacts of various constituents

Calcium silicate-based cements have superior sealing ability, bioactivity, and marginal adaptation, which make them suitable for different dental treatment applications. However, they exhibit some drawbacks such as long setting time and poor handling characteristics. To overcome these limitations calcium silicates are engineered with various constituents to improve specific characteristics of the base material, and are the focus of this review. An electronic search of the PubMed, MEDLINE, and EMBASE via OVID databases using appropriate terms and keywords related to the use, application, and properties of calcium silicate-based cements was conducted. Two independent reviewers obtained and analyzed the full texts of the selected articles. Although the effects of various constituents and additives to the base Portland cement-like materials have been investigated, there is no one particular ingredient that stands out as being most important. Applying nanotechnology and new synthesis methods for powders most positively affected the cement properties.

Surface microhardness of different thicknesses of a premixed bioceramic material with or without the application of a moist cotton pellet

Background:

This study was conducted to assess the effect of thickness and hydration condition on the surface microhardness of Endosequence Root Repair Material putty (ERRM; Brasseler USA, Savannah, GA), a premixed bioceramic material.

Materials and Methods:

Polymethyl methacrylate cylindrical molds with an internal diameter of 4 mm and three heights of 2, 4, and 6 mm were fabricated. In Group 1 (dry condition), the molds with heights of 2, 4, and 6 mm (10 molds of each) were filled with ERRM. In Groups 2 and 3 (wet condition), a distilled water- or phosphate-buffered saline (PBS)-moistened cotton pellet was placed directly on the upper surface of ERRM, respectively. The lower surface of ERRM was in contact with floral foams soaked with human blood. After 4 days, Vickers microhardness of the upper surface of ERRM was tested. The data were analyzed using two-way analysis of variance. Significance level was set at P < 0.05.

Results:

No significant difference was found between the microhardness of three thicknesses of ERRM (2, 4, and 6 mm) with or without placing a distilled water- or PBS-moistened cotton pellet over the material (P > 0.05).

Conclusion:

Based on the results of this study, it could be concluded that placing a moistened cotton pellet on ERRM putty up to 6 mm thick might be unnecessary to improve its surface microhardness and hydration characteristics.

Bioactivity of MTA Plus, Biodentine and an experimental calcium silicate-based cement on human osteoblast-like cells

AIM

To compare the bioactivity of Biodentine (BIO, Septodont), MTA Plus (MTA P, Avalon) and calcium silicate experimental cement (CSC) with resin (CSCR) associated with zirconium (CSCR ZrO₂ ) or niobium (CSCR Nb₂ O₅ ) oxide as radiopacifiers.

METHODOLOGY

According to the relevance of osteoblastic cell response for mineralized tissue repair, human osteoblastic cells (Saos-2) were exposed to test materials and assessed for viability (MTT), cell proliferation, gene expression of alkaline phosphatase (ALP) osteogenic marker by real-time PCR (RT-qPCR), ALP activity assay and alizarin red staining (ARS) to detect mineralization nodule deposition in osteogenic medium. Unexposed cells acted as the control group (C). Statistical analysis was carried out using ANOVA and the Bonferroni post-test (P < 0.05).

RESULTS

All tested cements showed dose-dependent responses in cell viability (MTT). Exposed cells revealed good viability (80-130% compared to the control group) in the highest dilutions of all types of cement. MTA P, BIO and CSCR ZrO₂ significantly increased the velocity of cell proliferation after three days of cell exposure in the wound-healing assay (P < 0.05), which corroborated MTT data. On day 3, the ALP transcript level increased, especially to CSCR Nb₂ O₅ (P < 0.05). All cements exhibited suitable ALP enzyme activity, highlighting the 7-day period of cell exposure. ARS, CSCR Nb₂ O₅ , revealed a significant potential to induce mineralization in vitro.

CONCLUSIONS

All materials had suitable biocompatibility and bioactivity. The MTA P, BIO and CSCR ZrO₂ groups had the highest viability rates and velocity of proliferation whilst the CSCR Nb₂ O₅ group produced more mineralized nodules.

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.

Pulp tissue response to Portland cement associated with different radio pacifying agents on pulpotomy of human primary molars

The objective of this research was to evaluate the response of Portland cement associated with different radio pacifying agents on pulp treatment of human primary teeth by clinical and radiographic exams and microscopic analysis. Thirty mandibular primary molars were randomly divided into the following groups: Group I - Portland cement; Group II - Portland cement with iodoform (Portland cement + CHI3 ); Group III - Portland cement with zirconium oxide (Portland cement + ZrO2 ); and treated by pulpotomy technique (removal of a portion of the pulp aiming to maintain the vitally of the remaining radicular pulp tissue using a therapeutic dressing). Clinical and radiographic evaluations were recorded at 6, 12 and 24 months follow-up. The teeth at the regular exfoliation period were extracted and processed for histological analysis. Data were tested using statistical analysis with a significance level of 5%. The microscopic findings were descriptively analysed. All treated teeth were clinically and radiographically successful at follow-up appointments. The microscopic analysis revealed positive response to pulp repair with hard tissue barrier formation and pulp calcification in the remaining roots of all available teeth. The findings of this study suggest that primary teeth pulp tissue exhibited satisfactory biological response to Portland cement associated with radio pacifying agents. However, further studies with long-term follow-up are needed to determine the safe clinical indication of this alternative material for pulp therapy of primary teeth.

An in vitro study of different material properties of Biodentine compared to ProRoot MTA

Introduction

The aim of this study was to compare solubility, microhardness, radiopacity, and setting time of Biodentine with ProRoot MTA.

Methods

Solubility in distilled water, radioopacity, and setting time were evaluated in accordance with International Standard ISO 6876:2001. In addition, the solubility in Phosphate Buffered Saline (PBS) buffer was determined. For microhardness-testing, ten samples of each cement were produced. All samples were loaded with a diamond indenter point with a weight of 100 g for 30s.

All data were analysed using the Student-t-test.

Results

Both materials fulfilled the requirements of the International Standard ISO 6876:2001 and showed a solubility of <3% after 24 h. At all exposure times Biodentine was significantly more soluble than ProRoot MTA (p < 0.0001). After immersion in PBS-buffer a precipitation of hydroxyapatite was visible.

The Vickers microhardness for Biodentine was significantly higher (62.35 ± 11.55HV) compared with ProRoot MTA (26.93 ± 4.66HV) (p < 0.0001).

ProRoot MTA was significantly more radiopaque (6.40 ± 0.06 mm Al) than Biodentine (1.50 ± 0.10 mm Al) (p < 0.0001).

The setting time for Biodentine (85.66 ± 6.03 min) was significantly lower than for ProRoot MTA (228.33 ± 2.88 min) (p < 0.0001).

Conclusions

Biodentine and ProRoot MTA displayed different material properties. The solubility of both cements was in accordance with the International Standard ISO 6876:2001, whereas ProRoot MTA showed a significantly lower solubility. With regard to microhardness, Biodentine may be used to replace dentine. The radioopacity of Biodentine did not fulfil the requirements laid down in the International Standard ISO 6876:2001. The setting time for ProRoot MTA is significantly higher. Both materials can be used in different indications where specific material properties may be favourable. Hence, the here tested material properties are of clinical relevance.

Solubility of a new calcium silicate-based root-end filling material

INTRODUCTION

The purpose of this study was to compare solubility of a new calcium silicate-based cement, Biodentine with three commonly used root-end filling materials viz. glass-ionomer cement (GIC), intermediate restorative material (IRM), and mineral trioxide aggregate (MTA).

MATERIALS AND METHODS

Twenty stainless steel ring molds were filled with cements corresponding to four groups (n = 5). The weight of 20 dried glass bottles was recorded. Samples were transferred to bottles containing 5 ml of distilled water and stored for 24 h. The bottles were dried at 105΀C and weighed. This procedure was repeated for 3, 10, 30, and 60 days. Data was analyzed with one-way analysis of variance (ANOVA) test (P < 0.05).

RESULTS

Biodentine demonstrated significantly higher solubility than MTA for 30- and 60-day immersion periods. Statistical difference was noted between the solubility values of Biodentine samples amongst each of the five time intervals.

CONCLUSIONS

Biodentine exhibited higher solubility in comparison with all other cements.

Calcium Silicate and Calcium Hydroxide Materials for Pulp Capping: Biointeractivity, Porosity, Solubility and Bioactivity of Current Formulations

Aim

The chemical-physical properties of novel and long-standing calcium silicate cements versus conventional pulp capping calcium hydroxide biomaterials were compared.

Methods

Calcium hydroxide–based (Calxyl, Dycal, Life, Lime-Lite) and calcium silicate–based (ProRoot MTA, MTA Angelus, MTA Plus, Biodentine, Tech Biosealer capping, TheraCal) biomaterials were examined. Calcium and hydroxyl ion release, water sorption, interconnected open pores, apparent porosity, solubility and apatite-forming ability in simulated body fluid were evaluated.

Results

All calcium silicate materials released more calcium. Tech Biosealer capping, MTA Plus gel and Biodentine showed the highest values of calcium release, while Lime-Lite the lowest. All the materials showed alkalizing activity except for Life and Lime-Lite. Calcium silicate materials showed high porosity values: Tech Biosealer capping, MTA Plus gel and MTA Angelus showed the highest values of porosity, water sorption and solubility, while TheraCal the lowest. The solubility of water-containing materials was higher and correlated with the liquid-to-powder ratio. Calcium phosphate (CaP) deposits were noted on materials surfaces after short aging times. Scant deposits were detected on Lime-Lite. A CaP coating composed of spherulites was detected on all calcium silicate materials and Dycal after 28 days. The thickness, continuity and Ca/P ratio differed markedly among the materials. MTA Plus showed the thickest coating, ProRoot MTA showed large spherulitic deposits, while TheraCal presented very small dense spherulites.

Conclusions

calcium silicate-based cements are biointeractive (ion-releasing) bioactive (apatite-forming) functional biomaterials. The high rate of calcium release and the fast formation of apatite may well explain the role of calcium silicate biomaterials as scaffold to induce new dentin bridge formation and clinical healing.

Radiopacifier particle size impacts the physical properties of tricalcium silicate-based cements

INTRODUCTION

The aim of this study was to evaluate the impact of radiopaque additive, bismuth oxide, particle size on the physical properties, and radiopacity of tricalcium silicate-based cements.

METHODS

Six types of tricalcium silicate cement (CSC) including CSC without bismuth oxide, CSC + 10% (wt%) regular bismuth oxide (particle size 10 μm), CSC + 20% regular bismuth oxide (simulating white mineral trioxide aggregate [WMTA]) as a control, CSC + 10% nano bismuth oxide (particle size 50-80 nm), CSC + 20% nano-size bismuth oxide, and nano WMTA (a nano modification of WMTA comprising nanoparticles in the range of 40-100 nm) were prepared. Twenty-four samples from each group were divided into 4 groups and subjected to push-out, surface microhardness, radiopacity, and compressive strength tests. Data were analyzed by 1-way analysis of variance with the post hoc Tukey test.

RESULTS

The push-out and compressive strength of CSC without bismuth oxide and CSC with 10% and 20% nano bismuth oxide were significantly higher than CSC with 10% or 20% regular bismuth oxide (P < .05). The surface microhardness of CSC without bismuth oxide and CSC with 10% regular bismuth oxide had the lowest values (P < .05). The lowest radiopacity values were seen in CSC without bismuth oxide and CSC with 10% nano bismuth oxide (P < .05). Nano WMTA samples showed the highest values for all tested properties (P < .05) except for radiopacity.

CONCLUSIONS

The addition of 20% nano bismuth oxide enhanced the physical properties of CSC without any significant changes in radiopacity. Regular particle-size bismuth oxide reduced the physical properties of CSC material for tested parameters.

Surface microhardness of three thicknesses of mineral trioxide aggregate in different setting conditions

Objectives

This study aimed to compare the surface microhardness of mineral trioxide aggregate (MTA) samples having different thicknesses and exposed to human blood from one side and with or without a moist cotton pellet on the other side.

Materials and Methods

Ninety cylindrical molds with three heights of 2, 4, and 6 mm were fabricated. In group 1 (dry condition), molds with heights of 2, 4, and 6 mm (10 molds of each) were filled with ProRoot MTA (Dentsply Tulsa Dental), and the upper surface of the material was not exposed to any additional moisture. In groups 2 and 3, a distilled water- or phosphate-buffered saline (PBS)-moistened cotton pellet was placed on the upper side of MTA, respectively. The lower side of the molds in all the groups was in contact with human blood-wetted foams. After 4 day, the Vickers microhardness of the upper surface of MTA was measured.

Results

In the dry condition, the 4 and 6 mm-thick MTA samples showed significantly lower microhardness than the 2 mm-thick samples (p = 0.003 and p = 0.001, respectively). However, when a distilled water- or PBS-moistened cotton pellet was placed over the MTA, no significant difference was found between the surface microhardness of samples having the abovementioned three thicknesses of the material (p = 0.210 and p = 0.112, respectively).

Conclusions

It could be concluded that a moist cotton pellet must be placed over the 4 to 6 mm-thick MTA for better hydration of the material. However, this might not be necessary when 2 mm-thick MTA is used.

Comparative Analysis of Selected Physicochemical Properties of Pozzolan Portland and MTA-Based Cements

Physicochemical properties of pozzolan Portland cement were compared to ProRoot MTA and MTA BIO. To test the pH, the samples were immersed in distilled water for different periods of time. After the pH analysis, the sample was retained in the plastic recipient, and the electrical conductivity of the solution was measured. The solubility and radiopacity properties were evaluated according to specification 57 of the American National Standard Institute/American Dental Association (ANSI/ADA). The statistical analyses were performed using ANOVA and Tukey's test at a 5% level of significance. Pozzolan Portland cement exhibited pH and electrical conductivity mean values similar to those of the MTA-based cements. The solubilities of all tested materials were in accordance with the ANSI/ADA standards. Only the MTA-based cements met the ANSI/ADA recommendations for radiopacity. It might be concluded that the pH and electrical conductivity of pozzolan Portland cement are similar to and comparable to those of MTA-based cements.

Comparative analysis of physicochemical properties of root perforation sealer materials

Objectives

This study evaluated the solubility, dimensional alteration, pH, electrical conductivity, and radiopacity of root perforation sealer materials.

Materials and Methods

For the pH test, the samples were immersed in distilled water for different periods of time. Then, the samples were retained in plastic recipients, and the electrical conductivity of the solution was measured. The solubility, dimensional alteration, and radiopacity properties were evaluated according to Specification No. 57 of the American National Standards Institute/American Dental Association (ANSI/ADA). Statistical analyses were carried out using analysis of variance (ANOVA) and Tukey's test at a significance level of 5%. When the sample distribution was not normal, a nonparametric ANOVA was performed with a Kruskal-Wallis test (α = 0.05).

Results

The results showed that white structural Portland cement (PC) had the highest solubility, while mineral trioxide aggregate (MTA)-based cements, ProRoot MTA (Dentsply-Tulsa Dental) and MTA BIO (Ângelus Ind. Prod.), had the lowest values. MTA BIO showed the lowest dimensional alteration values and white PC presented the highest values. No differences among the tested materials were observed in the the pH and electrical conductivity analyses. Only the MTA-based cements met the ANSI/ADA recommendations regarding radiopacity, overcoming the three steps of the aluminum step wedge.

Conclusions

On the basis of these results, we concluded that the values of solubility and dimensional alteration of the materials were in accordance with the ANSI/ADA specifications. PCs did not fulfill the ANSI/ADA requirements regarding radiopacity. No differences were observed among the materials with respect to the pH and electrical conductivity analyses.

Effect of ultrasonication on physical properties of mineral trioxide aggregate

Aim. To evaluate the effect on physical properties of Mineral Trioxide Aggregate (MTA) of using direct hand compaction during placement and when using hand compaction with indirect ultrasonic activation with different application times. Methods. One hundred acrylic canals were obturated in 3 increments with MTA in sample sizes of 10. One group was obturated by hand with an endodontic plugger and the remainder obturated with indirect ultrasonic application, with times ranging from 2 seconds to 18 seconds per increment. Microhardness values, dye penetration depths, and radiographs of the samples were evaluated. Results. As ultrasonic application time per increment increased, microhardness values fell significantly (P < 0.001) while dye penetration values increased (P < 0.001). Microhardness of MTA ultrasonicated for 2 seconds was significantly higher than hand compaction (P = 0.03). Most radiographic voids were visible in the hand-compacted group (P < 0.001), which also had higher dye penetration depths than the 2-second ultrasonicated samples. Ultrasonication of MTA for 10–18 seconds resulted in significantly more voids than 2–8 seconds of ultrasonication (P = 0.02). Conclusion. The use of ultrasonics with MTA improved the compaction and flow of MTA, but excessive ultrasonication adversely affected MTA properties. A time of 2 seconds of ultrasonication per increment presented the best compromise between microhardness values, dye penetration depths, and lack of radiographic voids.

New treatment option for an incomplete vertical root fracture--a preliminary case report

Instead of extraction this case report presents an alternative treatment option for a maxillary incisor with a vertical root fracture (VRF) causing pain in a 78-year-old patient. After retreatment of the existing root canal filling the tooth was stabilized with a dentine adhesive and a composite restoration. Then the tooth was extracted, the VRF gap enlarged with a small diamond bur and the existing retrograde root canal filling removed. The enlarged fracture line and the retrograde preparation were filled with a calcium-silicate-cement (Biodentine). Afterwards the tooth was replanted and a titanium trauma splint was applied for 12d. A 24 months clinical and radiological follow-up showed an asymptomatic tooth, reduction of the periodontal probing depths from 7 mm prior to treatment to 3 mm and gingival reattachment in the area of the fracture with no sign of ankylosis. Hence, the treatment of VRF with Biodentine seems to be a possible and promising option.

Effects of various mixing techniques on physical properties of white mineral trioxide aggregate

INTRODUCTION

The aim of this study was to evaluate the effects of three different mixing techniques on surface microhardness, initial setting time, and phase formation of white mineral trioxide aggregate.

METHODS

Twenty-one cylindrical glass tubes were selected and divided into three groups of seven in each (n = 7). White mineral trioxide aggregate (WMTA) in groups A, B, and C were mixed by conventional, trituration, and ultrasonic techniques, respectively. Cements were mixed and packed into the glass tubes and incubated at 37°C for 3 days. After incubation, samples were subjected to microhardness evaluation, and four specimens from each group were prepared and observed under a scanning electron microscopy and X-ray diffraction. For setting time assessment, WMTA was mixed in three parts again, and Gilmore needle test was performed until the initial setting time of cement. Data were analyzed by one-way anova and post hoc Tukey's test.

RESULTS

Samples mixed by trituration technique significantly showed the highest microhardness (P < 0.001) and the lowest setting time, while the ultrasonically mixed specimens significantly revealed the highest setting time in comparison with other groups (P < 0.001). Samples mixed by trituration technique showed the highest uniformity in the bulk and highest amount of hydrated calcium silicate (CS) phases, while the lowest value was observed in ultrasonically mixed cements, which also showed the highest amount of anhydrated CS phases.

CONCLUSION

Trituration and conventional techniques were more suitable mixing methods for mineral trioxide aggregate in comparison with ultrasonic technique. Trituration resulted in better hydration and crystallization, which prevents clustering of powder and reduces voids and setting time of mixed cement.

Removal of white mineral trioxide aggregate cement: a promising approach

Removal of MTA from dentin by applying 37% hydrochloric acid (HCl) to reduce microhardness and push-out bond strength. Forty dentin slices were filled with WMTA and divided into two groups (n = 20). Ten slices remained untreated while others were exposed to either HCl or phosphate buffer saline (PBS) and all samples were subjected to pushout test. The mode of bond failures was determined by SEM analysis. Later, twenty glass tubes were filled with WMTA and divided into two groups (n = 10). One side of tube was exposed to HCl or PBS while the other side remained untreated and the microhardness was analyzed by testing machine. HCl showed significantly lower pushout strength and microhardness values (P = 0.0001), (P = 0.0001). HCl treated samples showed mixed bond failures dominantly, while PBS samples mostly showed adhesive failures. The results of this study can suggest the 37% HCl as an effective solution to aid the removal of MTA from the dentin surfaces.

Rat subcutaneous tissue response to MTA Fillapex® and Portland cement

The aim of this study was to evaluate the response of rat subcutaneous tissue to MTA Fillapex® (Angelus), an experimental root canal filling material based on Portland cement and propylene glycol (PCPG), and a zinc oxide, eugenol and iodoform (ZOEI) paste. These materials were placed in polyethylene tubes and implanted into the dorsal connective tissue of Wistar rats for 7 and 15 days. The specimens were stained with hematoxylin and eosin, and evaluated regarding inflammatory reaction parameters by optical microscopy. The intensity of inflammatory response against the sealers was analyzed by two blinded and previously calibrated examiners for all experimental periods (kappa=0.96). The histological evaluation showed that all materials caused a moderate inflammatory reaction at 7 days, which subsided with time. A greater inflammatory reaction was observed at 7 days in the tubes filled with ZOEI paste. Tubes filled with MTA Fillapex presented some giant cells, macrophages and lymphocytes after 7 days. At 15 days, the presence of fibroblasts and collagen fibers was observed indicating normal tissue healing. The tubes filled with PCPG showed similar results to those observed in MTA Fillapex. At 15 days, the inflammatory reaction was almost absent at the tissue, with several collagen fibers indicating normal tissue healing. Data were analyzed by the nonparametric Kruskal-Wallis test (α=0.05). Statistically significant difference (p<0.05) was found only between PCPG at 15 days and ZOEI at 7 days groups. No significant differences were observed among the other groups/periods (p>0.05). MTA Fillapex and Portland cement added with propylene glycol had greater tissue compatibility than the PCPG paste.

In vitro assessment of mineral trioxide aggregate setting in the presence of interstitial fluid alone

INTRODUCTION

The aim of this study was to determine the ability of white mineral trioxide aggregate (MTA) Angelus (Solucoes Odontologicas, Londrina, Brazil) to set in 24 hours within the root canal in the presence of an intrinsic moisture source (interstitial fluid) alone without the need for moist cotton pellet placement.

METHODS

Extracted teeth were used to simulate the open apex situation. MTA was placed to a depth of 4 mm and allowed to set for 24 hours in the following test groups: a current protocol group with a moist cotton pellet, a test group with no moist cotton pellet placement, and positive and negative control groups with varnished roots. The teeth were embedded in florist sponges immersed in fetal bovine serum at 13.3-kPa pressure. The MTA set was tested using the Vickers hardness test, and the data were analyzed using analysis of variance.

RESULTS

The greatest mean surface hardness values were observed in the current protocol group (80.7 ± 35.6), but this was not statistically different when compared with the test group without a moist cotton pellet (78.3 ± 53.7) or the control groups.

CONCLUSIONS

Moist cotton pellet placement may not be essential for MTA setting in apexification procedures or situations in which the apical surface of the MTA is against a moist opening of greater than 1 mm.

Bond strength of adhesive systems to mineral trioxide aggregate with different time intervals

INTRODUCTION

The aim of this study was to compare the shear bond strengths of various adhesive systems to white mineral trioxide aggregate (WMTA) with different time intervals.

METHODS

Two hundred cylindrical acrylic blocks with a hole (4-mm diameter and 2-mm height) were prepared. The holes were filled with WMTA, and the specimens were allocated into 5 groups. Forty specimens were stored for 4, 24, 48, 72, and 96 hours at 37°C and 100% humidity. Each group was divided into 4 subgroups: group 1, All-Bond SE (Bisco Inc, Schaumburg, IL); group 2, All-Bond 3 (Bisco Inc); group 3, One-Step Plus (Bisco Inc); and group 4, control. After the application of adhesive systems, composite resin (Aelite, Bisco) was applied over the WMTA. Shear bond strengths were measured using a universal testing machine, and the data were subjected to 1-way analysis of variance and the Scheffé post hoc test.

RESULTS

There was a significant difference between the 4-, 24-, 48-, 72-, and 96-hour measurements in all of the adhesive systems (P < .001). Among all time intervals, group 3 showed significantly higher bond strengths to WMTA than the other groups (P < .001). Groups 1 and 2 were similar (P = .365).

CONCLUSIONS

It was concluded that if a longer waiting time can be practiced after the mixing of WMTA, higher shear bond strength measurements can be obtained. Also, when WMTA was used with total-etch adhesive systems, it showed better shear bond strength.

Effects of bone graft materials on the microhardness of mineral trioxide aggregate

INTRODUCTION

Large through-and-through lesions have been reported to heal faster and better when filled with bone graft material at the time of an apicoectomy. It is unknown what effect these have on retrograde filling materials such as white mineral trioxide aggregate (WMTA). In this study, the null hypothesis was tested that the presence of bone graft materials does not affect the microhardness of WMTA.

METHODS

Freshly mixed WMTA was condensed into acrylic cylinders and preincubated aerobically at 37°C for 1 hour. Cylinders were immersed in simulated body fluid in close proximity to graft materials: xenograft (Bio-Oss, n = 60), freeze-dried bone allograft (MinerOss, n = 60), demineralized freeze-dried bone allograft (OraGraft, n = 40), and allograft (Puros, n = 60). Knoop microhardness of half the samples in each group was evaluated after 2 weeks of incubation and the remainder at 4 weeks. The values for each group were then compared with 2-way analysis of variance and Bonferroni post hoc tests.

RESULTS

WMTA microhardness values for Bio-Oss, MinerOss, and Puros groups were lower than those for OraGraft and control groups regardless of incubation period (P < .001); values for the OraGraft group were higher than those for the control group at 2 weeks (P < .001), with no difference at 4 weeks. Microhardness values were higher at 4 weeks compared with 2 weeks for MinerOss (P < .05), OraGraft (P < .01), and control (P < .001), with no differences for Bio-Oss and Puros groups. The null hypothesis was rejected.

CONCLUSIONS

Demineralized and mineralized graft materials appear to have a differential effect on the microhardness of WMTA.