Mineral Trioxide Aggregate-A Review of Properties and Testing Methodologies

Effect of radiopacifier and liquid in the physicochemical and biological properties of calcium silicate clinker Angelus: A laboratory investigation

The aim of this study was to evaluate the effect of radiopacifier calcium tungstate and manipulation with distilled water (DW) or liquid with additives (LA) on calcium silicate clinker Angelus (CL) properties, compared with MTA (Angelus, Brazil) and MTA Repair HP (MTAHP, Angelus, Brazil). The physicochemical properties, cellular viability and bioactivity were evaluated. ANOVA/Tukey and Bonferroni tests were performed (α = 0.05). There was no difference in material setting time (p > 0.05). MTA and MTAHP were similar (p > 0.05) and had greater radiopacity than CL + DW and CL + LA (p < 0.05). All experimental materials showed mass increase, alkalinisation capacity, besides biocompatibility and bioactivity at 3 and 7 days. The different liquids had no influence in the biological properties and bioactivity of the calcium silicate clinker Angelus. Calcium tungstate provided radiopacity, without changing the setting time, maintaining the mass increase and alkalinisation ability of the calcium silicate materials.

The effect of three additives on properties of mineral trioxide aggregate cements: a systematic review and meta-analysis of in vitro studies

BACKGROUND

Several efforts have been made to improve mechanical and biological properties of calcium silicate-based cements through changes in chemical composition of the materials. This study aimed to investigate the physical (including setting time and compressive strength) and chemical (including calcium ion release, pH level) properties as well as changes in cytotoxicity of mineral trioxide aggregate (MTA) after the addition of 3 substances including CaCl2, Na2HPO4, and propylene glycol (PG).

METHODS

The systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Electronic searches were performed on PubMed, Embase, and Scopus databases, spanning from 1993 to October 2023 in addition to manual searches. Relevant laboratory studies were included. The quality of the included studies was assessed using modified ARRIVE criteria. Meta-analyses were performed by RevMan statistical software.

RESULTS

From the total of 267 studies, 24 articles were included in this review. The results of the meta-analysis indicated that addition of PG increased final setting time and Ca2+ ion release. Addition of Na2HPO4 did not change pH and cytotoxicity but reduced the final setting time. Incorporation of 5% CaCl2 reduced the setting time but did not alter the cytotoxicity of the cement. However, addition of 10% CaCl2 reduced cell viability, setting time, and compressive strength.

CONCLUSION

Inclusion of 2.5% wt. Na2HPO4 and 5% CaCl2 in MTA can be advisable for enhancing the physical, chemical, and cytotoxic characteristics of the admixture. Conversely, caution is advised against incorporating elevated concentrations of PG due to its retarding effect.

TRIAL REGISTRATION

PROSPERO registration number: CRD42021253707.

Cell Biological and Antibacterial Evaluation of a New Approach to Zirconia Implant Surfaces Modified with MTA

Peri-implantitis continues to be one of the major reasons for implant failure. We propose a new approach to the incorporation of MTA into zirconia implant surfaces with Nd:YAG laser and investigate the biological and the microbiological responses of peri-implant cells. Discs of zirconia stabilized with yttria and titanium were produced according to the following four study groups: Nd:YAG laser-textured zirconia coated with MTA (Zr MTA), Nd:YAG laser-textured zirconia (Zr textured), polished zirconia discs, and polished titanium discs (Zr and Ti). Surface roughness was evaluated by contact profilometry. Human osteoblasts (hFOB), gingival fibroblasts (HGF hTERT) and S. oralis were cultured on discs. Cell adhesion and morphology, cell differentiation markers and bacterial growth were evaluated. Zr textured roughness was significantly higher than all other groups. SEM images reveal cellular adhesion at 1 day in all samples in both cell lines. Osteoblasts viability was lower in the Zr MTA group, unlike fibroblasts viability, which was shown to be higher in the Zr MTA group compared with the Zr textured group at 3 and 7 days. Osteocalcin and IL-8 secretion by osteoblasts were higher in Zr MTA. The Zr textured group showed higher IL-8 values released by fibroblasts. No differences in S. oralis CFUs were observed between groups. The present study suggests that zirconia implant surfaces coated with MTA induced fibroblast proliferation and osteoblast differentiation; however, they did not present antibacterial properties.

Synthesis of a Calcium Silicate Cement Containing a Calcinated Strontium Silicate Phase

Objectives

The positive effects of strontium on dental and skeletal remineralization have been confirmed in the literature. This study aimed to assess the properties of a calcium silicate cement (CSC) containing a sintered strontium silicate phase.

Materials and Methods

The calcium silicate and strontium silicate phases were synthesized by the sol-gel technique. Strontium silicate powder in 0 (CSC), 10 (CSC/10Sr), 20 (CSC/20Sr), and 30 (CSC/30Sr) weight percentages was mixed with calcium silicate powder. Calcium chloride was used in the liquid phase. X-ray diffraction (XRD) of specimens was conducted before and after hydration. The setting time and compressive strength were assessed at 1 and 7 days after setting. The set discs of the aforementioned groups were immersed in the simulated body fluid (SBF) for 1 and 7 days. The ion release profile was evaluated by inductively coupled plasma-optical emission spectrometry (ICP-OES). Biomineralization on the specimen surface was evaluated by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Data were analyzed by the Kolmogorov-Smirnov test, one-way and mixed ANOVA, Levene's test, and LSD post hoc test (P  < 0.05).

Results

Except for an increasement in the peak intensity of hydrated specimens, XRD revealed no other difference in the crystalline phases of hydrated and nonhydrated specimens. The compressive strength was not significantly different at 1 and 7 days in any group (P  > 0.05). The setting time significantly decreased by an increase in percentage of strontium (P  < 0.05). Release of Ca and Si ions significantly decreased by an increase in percentage of strontium (P  < 0.05). SEM/EDS showed the formation of calcium phosphate deposits at 1 and 7 days.

Conclusion

Incorporation of 10-30 wt% sintered strontium silicate phase as premixed in CSC can significantly decrease the setting time without compromising the compressive strength or biomineralization process of the cement.

In Vitro Comparison of Differences in Setting Time of Premixed Calcium Silicate-Based Mineral Trioxide Aggregate According to Moisture Content of Gypsum

Recently, a paste-type premixed calcium silicate-based mineral trioxide aggregate (MTA) product that quickly solidifies through a pozzolanic reaction was introduced to replace existing MTA, which has the disadvantage of a long setting time. In this study, we evaluated the effect of moisture content in the root canal on the setting time of premixed calcium silicate-based MTA in a simulated root canal environment using Endoseal MTA and Well-Root ST, among commercially available products. The setting time was measured according to ISO 6876/2012. A mold made using grades 2, 3, and 4 dental gypsum according to the classification of ISO 6873/2013 was used to reproduce the difference in moisture environment. Differences in moisture content were measured using micro-computed X-ray tomography (micro-CT). The micro-CT results showed that the moisture content was the highest and lowest in the grade 2 and 4 gypsum molds, respectively. Moreover, the setting time indicated by the manufacturer was the shortest for the grade 2 gypsum mold. Hence, the differences in moisture content significantly affect the setting time of MTA. This result can help set future experimental conditions and develop premixed calcium silicate-based MTA products.

Remineralization ability of different root canal sealers

Aims

This research was designed to contrast the biocompatibility and remineralization ability of different sealers (BioRoot, MTA-FillApex and GuttaFlow-Bioseal).

Method

Twenty rabbits were used in this study, they were randomly divided into 4 groups equally depending on the observation time"3,7,14, and 28 days" post-implantation. Each rabbit was generally anesthetized,"7cm"long incision was made on the skin of the right and left sides of the ventral aspect of the mandible of each rabbit, 4 bony cavities of approximately"5mm"in depth and"2mm"in diameter (2 cavities on the left side and 2 cavities on the right side of mandible of each rabbit) were made in the cortical surface of the buccal alveolar bone. The sealers mixed depend on manufactural instructions and immediately insert into the prepared cavities (in the right side the BioRoot and MTA-FillApex were placed while on the left side, GuttaFlow-Bioseal was placed in one cavity and the other cavity was left unfilled as control).The same volume of each sealer was placed in the corresponding cavity using disposable syringes. After each observation period, the animals were sacrificed and bone biopsy from the tested area was taken and examined histologically using Olympus light microscopy at"400X"magnification.

Results

The obtained data were analyzed through non-parametric statistical tests using SPSS software version"22".Kruskal-Wallis test and Mann - Whitney test were utilized at"0.05"levels of significance to evaluate the results. GuttaFlow-Bioseal displayed excellent biocompatibility in comparison to other groups indicated by low inflammatory tissue reaction at all evaluation intervals. While the BioRoot group represented better osteo-conductivity although statistically not significant than GuttaFlow-Bioseal group.

Conclusion

BioRoot and GuttaFlow-Bioseal showed higher osteo-conductivity and biocompatibility than MTA-FillApex. However, all sealer used in this study were well tolerated by bone tissue and might accelerate bone repair.

Dimensional changes of endodontic sealers-An in vitro model simulating a clinical extrusion scenario during 18 months

OBJECTIVES

To examine the dimensional changes of endodontic sealers during 18 months using three-dimensional (3D) surface scanning and subtraction radiography in a novel in vitro sealer-extrusion model.

MATERIAL AND METHODS

Fifty endodontically instrumented acrylic teeth were randomly allocated to five groups (n = 10) filled with Apexit Plus, AH Plus, BioRoot RCS, TubliSeal EWT, and gutta-percha (control). Freshly mixed sealers were intentionally extruded during obturation. All teeth were immersed in a physiologic solution for up to 18 months. Blinded 3D surface scans (resolution: ~10 μm) and digital radiographs of the teeth were obtained at baseline (immediately after obturation); and then after 1 week, and at 1, 3, and 18 months. For blinded assessment of sealer dimensional change, 3D models and radiographs were superimposed using specific software. Volumetric differences, root mean square (RMS), and area change from subtraction radiography measured at each period within each sealer group were thereafter calculated. Repeated measures analyses were done with Bonferroni adjustment for multiple comparisons; standard errors, p values, and 95% confidence intervals (CI) were reported.

RESULTS

Analyses of the volumetric data confirmed significant, progressive material loss for Apexit Plus when compared to the other investigated sealers or the control group (p ≤ 0.02). Immersion period significantly influenced the volumetric dimensional changes of Apexit Plus already after 1 month (p < 0.01). For TubliSeal EW, the effect of the immersion period on the dimensional changes was noted after immersion for 3 months (p ≤ 0.02), while for BioRoot RCS this was evident only at 18 months (p < 0.01). Same trends were noted for the RMS data, whereas progressive dimensional changes using subtraction radiography only revealed significant changes for Apexit Plus (p = 0.01).

CONCLUSIONS

The largest dimensional changes were shown by Apexit Plus, followed by Tubliseal EWT and BioRoot RCS. AH Plus remained stable throughout 18 months.

Bioceramics in Endodontics: Updates and Future Perspectives

Bioceramics, with excellent bioactivity and biocompatibility, have been widely used in dentistry, particularly in endodontics. Mineral trioxide aggregate (MTA) is the most widely used bioceramic in endodontics. Recently, many new bioceramics have been developed, showing good potential for the treatment of endodontic diseases. This paper reviews the characteristics of bioceramics and their applications in various clinical endodontic situations, including root-end filling, root canal therapy, vital pulp therapy, apexification/regenerative endodontic treatment, perforation repair, and root defect repair. Relevant literature published from 1993 to 2023 was searched by keywords in PubMed and Web of Science. Current evidence supports the predictable outcome of MTA in the treatment of endodontic diseases. Although novel bioceramics such as Biodentine, EndoSequence, and calcium-enriched mixtures have shown promising clinical outcomes, more well-controlled clinical trials are still needed to provide high-level evidence for their application in endodontics. In addition, to better tackle the clinical challenges in endodontics, efforts are needed to improve the bioactivity of bioceramics, particularly to enhance their antimicrobial activity and mechanical properties and reduce their setting time and solubility.

Analysis of Pulp Tissue Viability and Cytotoxicity of Pulp Capping Agents

The present research study assessed the cell viability and cytotoxic effect of mineral tri-oxide aggregate (MTA), Tetric N-Bond Universal bonding agent, Theracal PT (pulpotomy treatment), and platelet-rich fibrin (PRF) as pulp capping agents on human dental pulp stem cells (hDPSCs). The cells were isolated from the pulp tissue of an extracted healthy permanent third molar. After four passages in Dulbecco’s Modified Eagle’s Medium, the primary cells were employed for the investigation. The test materials and untreated cells (negative control) were subjected to an Methylthiazol-diphenyl-tetrazolium (MTT) cytotoxicity assay and assessed at 24-, 48-, and 72-h intervals. The Wilcoxon matched-paired t-test and Kruskal−Wallis analysis of variance (ANOVA) test were applied (p < 0.05). PRF imparted the highest cell viability at 48 h (p < 0.001), followed by MTA, Theracal PT, and Tetric N-Bond. Similarly, PRF had the highest potential to enhance cell proliferation and differentiation (p < 0.001), followed by Theracal PT, MTA, and the bonding agent at the end of 24 h and 72 h, respectively. Finally, PRF sustained the viability of human primary dental pulp stem cells more effectively than Theracal PT and MTA; however, the application of a Tetric N-Bond as a pulp capping agent was ineffective.

Characterization, Physical Properties, and Biocompatibility of Novel Tricalcium Silicate-Chitosan Endodontic Sealer

OBJECTIVE

 The purpose of this study was to compare the characteristics, physical properties, and biocompatibility of the novel tricalcium silicate-chitosan (TCS-C) sealer with AH Plus and Sure-Seal Root.

MATERIALS AND METHODS

 The TCS-C powder was prepared by mixing tricalcium silicate with 2% water-soluble chitosan at a 5:1 ratio, followed by sufficient addition of 10 g/mL ratio of double-distilled water to form a homogeneous cement. Material characterizations (the Fourier Transform InfraRed [FTIR] and X-ray diffraction [XRD]), physical property investigations (flow and film thickness), and cytotoxicity tests in 3T3 mouse embryo fibroblast cell (MTT assay method) were performed on sealers, and the results were compared with those of the commercial products.

STATISTICAL ANALYSIS

 Statistical analysis was performed on flow and film thickness. The normality of the data was tested using the Shapiro-Wilk test. Statistical analysis was performed with one-way analysis of variance (ANOVA). The level of significance was set at p < 0.05.

RESULTS

 The TCS-C showed a mean flow of 31.98 ± 0.68 mm, compared with Sure Seal Root at 26.38 ± 0.69 mm and AH Plus at 26.50 ± 0.12 mm. The TCS-C showed a mean film thickness of 60 ± 10.0 mm compared with Sure-Seal Root at 50 ± 10.0 mm and AH Plus at 40 ± 15.8 mm. The TCS-C exhibited low to no cytotoxicity in fibroblast cell at all concentrations and exposure times.

CONCLUSION

 Adding water-soluble chitosan may improve the physical and biologic properties of tricalcium silicate cement. The novel TCS-C sealer did not fully meet the physical properties of an endodontic sealer, but it was not cytotoxic to fibroblast cells.

MTA-Based Cements: Biocompatibility and Effects on the Gene Expression of Collagen Type 1 and TGF-β1

Objective

This study sought to evaluate the biocompatibility of Neomineral Trioxide Aggregate (Neo-MTA), MTA Repair High Plasticity (MTA-HP), and Mineral Trioxide Aggregate-Angelus white (MTA-Ang) in fibroblasts of human dental pulp.

Materials and Methods

Morphology was evaluated after 24 h of incubation. LIVE/DEAD assay and cell adhesion tests were performed at 24 h of treatment. Cell proliferation assays (MTSs) and Annexin V were performed at 48 h incubation with different treatments. The expression of Col-1 and TGF-β1 was tested by endpoint PCR at 5 days of treatment.

Results

Morphological changes were observed in all groups. Neo-MTA and MTA-Ang were associated with increased cell viability, and all materials induced apoptosis, with a higher percentage in the MTA-HP group than in the other groups. In the LIVE/DEAD assay, there was more damage to the cell membrane in the group of cells treated with MTA-HP than in the other groups.

Conclusion

Neo-MTA and MTA-Ang presented similar biocompatibility, and both showed greater biocompatibility than MTA-HP. MTA-HP and MTA-Ang increased Col-1A gene expression, and Neo-MTA and MTA-Ang increased TGF-β1 gene expression in a similar way.

Comparative evaluation of the effect of cold ceramic and MTA-Angelus on cell viability, attachment and differentiation of dental pulp stem cells and periodontal ligament fibroblasts: an in vitro study

BACKGROUND

Biocompatibility and induction of mineralized tissue formation are the properties expected from a material used in vital pulp therapy and repair of perforations. Cold ceramic (SJM, Iran; CC) is a newly introduced calcium silicate-based cement for above mentioned therapeutic applications. This in-vitro study aimed to compare the effect of CC and White MTA-Angelus (MTA) on cell viability, attachment, odontogenic differentiation, and calcification potential of human dental pulp stem cells (DPSCs) and periodontal ligament fibroblasts (PDLFs).

METHODS

Cell viability of DPSCs and PDLFs was assessed using MTT on days 1, 3, 7, and 14 (n = 9) in contact with freshly mixed and set states of CC and MTA. Field emission scanning electron micrographs (FESEM) were taken to evaluate cell-bioceramic interaction (n = 6). Gene expression levels of osteo/odontogenic markers (Dentin sialophosphoprotein, Dentin matrix protein 1, Collagen type I alpha 1, and Alkaline phosphatase (DSPP, DMP1, COL 1A1, and ALP, respectively) (n = 8) were assessed using qrt-PCR. ALP enzymatic activity was evaluated to assess the mineralization potential. A two-way ANOVA test was applied, and p < 0.05 was considered to be statistically significant.

RESULTS

The effect of freshly mixed and set MTA and CC on the survival of DPSCs and PDLFs in all study groups was statistically similar and comparable to the positive control group (p > 0.05); the only exception was for the viability of PDLFs in contact with freshly mixed cements on day 1, showing a more significant cytotoxic effect compared to the control and the set state of materials (p < 0.05). PDLFs attached well on CC and MTA. The spread and pseudopodium formation of the cells increased on both samples from day 1 to day 14. Contact of MTA and CC with DPSCs similarly increased expression of all dentinogenesis markers studied on days 7 and 14 compared to the control group (p < 0.001), except for DSPP expression on day 7 (p = 0.46 and p = 0.99 for MTA and CC, respectively).

CONCLUSIONS

Within the limitation of this in-vitro study, cold ceramic and MTA-Angelus showed high biocompatibility and induced increased expression of osteo/dentinogenic markers. Therefore, cold ceramic can be a suitable material for vital pulp therapy and the repair of root perforations.

Effect of bioactive glass addition on the physical properties of mineral trioxide aggregate

Background

The addition of bioactive glass (BG), a highly bioactive material with remineralization potential, might improve the drawback of weakening property of mineral trioxide aggregates (MTA) when it encounters with body fluid. This study aims to evaluate the effect of BG addition on physical properties of MTA.

Methods

ProRoot (MTA), and MTA with various concentrations of BG (1, 2, 5 and 10% BG/MTA) were prepared. Simulated body fluid (SBF) was used to investigate the effect of the storage solution on dentin remineralization. Prepared specimens were examined as following; the push-out bond strength to dentin, compressive strength, setting time solubility and X-ray diffraction (XRD) analysis.

Results

The 2% BG/MTA showed higher push-out bond strengths than control group after 7 days of SBF storage. The 2% BG/MTA exhibited the highest compressive strength. Setting times were reduced in the 1 and 2% BG/MTA groups, and solubility of all experimental groups were clinically acceptable. In all groups, precipitates were observed in dentinal tubules via SEM. XRD showed the increased hydroxyapatite peaks in the 2, 5 and 10% BG/MTA groups.

Conclusion

It was verified that the BG-added MTA increased dentin push-out bond strength and compressive strength under SBF storage. The addition of BG did not negatively affect the MTA maturation reaction; it increased the amount of hydroxyapatite during SBF maturation.

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.

Comparative Evaluation of Mineral Trioxide Aggregate Obturation Using Four Different Techniques-A Laboratory Study

This study aimed to compare the density of mineral trioxide aggregate (MTA) as a root canal filling material in the apical 5 mm of artificial root canals. Forty transparent acrylic blocks with 30-degree curved canals were instrumented and allocated into four compaction technique groups (n = 10): Lawaty (hand files); gutta-percha (GP) points; auger (nickel–titanium rotary files in reverse mode); and plugger technique. Filled canals were weighed after setting the MTA to calculate difference in mass. Two postoperative radiographs compared radiopacity by measuring luminance variations at 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm from the root apex. Obturation time was measured using a digital chronometer. The significance level was set to p < 0.05. The plugger group had a lower mass. Relative luminance was significantly higher for the Lawaty group than the plugger group at all examined apical levels. The relative luminance of the auger and GP groups were significantly higher than the plugger group at depths between 0.5 mm and 2 mm. Relative luminance was highest for the Lawaty technique at all depths between 0.5 mm and 4 mm. The Lawaty technique group was associated with increased obturation time compared with pluggers. Compacting MTA in curved canals with the Lawaty technique has the highest mass and radiopacity but requires more time.

Long-term pH Alterations in the Periradicular Area Following the Application of Calcium Hydroxide and MTA

STATEMENT OF THE PROBLEM

A rise in pH and the presence of calcium ions play an important role in prevention or management of external root resorption.

PURPOSE

This study assessed the long-term pH alterations in the periradicular area following the application of calcium hydroxide (CH) and mineral trioxide aggregate (MTA) intracanal medicaments.

MATERIALS AND METHOD

This in vitro, experimental study evaluated 45 single-canal extracted human teeth. After decoronation and root canal instrumentation, defects (3×3×1mm) were created in the middle third of the roots. Following smear layer removal, the root surface (except for the defect) was sealed with nail varnish. Five teeth served as negative controls and were filled with distilled water. The remaining 40 teeth were randomly divided into two groups (n=20) for application of MTA and CH as intr-acanal medicaments. Periapical radiographs were obtained to ensure optimal quality of obturation. After coronal sealing with glass ionomer, the teeth were incubated at 37°C, and their pH was measured at 1 and 2 weeks, and 1 and 3 months, using a pH-meter. Data were analyzed using one-way ANOVA, Tukey's test and Bonferroni adjustment.

RESULTS

The mean pH was significantly higher in CH group at 1 and 2 weeks (p< 0.01) but no difference was noted at 1 and 3 months (p= 0.52). The mean pH in both groups was significantly higher at 2 weeks compared with other time points (p< 0.05).

CONCLUSION

CH may be preferred for use in the first weeks following the initiation of root resorption to provide a high pH. MTA can be later applied to maintain the high pH for a longer period of time without the need for medicament exchange.

Antifungal Effectiveness between Tricalcium Silicate-White Portland Cements Added Bi2O3 and Mineral Trioxide Aggregate Against Candida albicans

Background

Candida albicans is the most dominant fungus found in root canal reinfection cases. This microorganism can withstand extreme pH, low oxygen levels, lack of nutrients, and penetrate the dentinal tubules so that it can resist the intracanal medicament. Root canal cement helps prevent microorganisms and causing root canal reinfection. MTA is one of the root canals cement which is widely used and has an excellent antifungal activity, but it is less beneficial economically. Tricalcium silicate-white Portland cement (WPC) has a similar main composition as MTA, except there is no Bi2O3 content that functions as a radiopacifier.

Objectives:

To fabricate a mixture of tricalcium silicate-WPC with Bi2O3 through a simple solution method and investigate antifungal activity's effectiveness between tricalcium silicate-WPC added Bi2O3 and MTA to C. albicans.

Materials and Methods:

The 80 g of tricalcium silicate-WPC was mixed with 20 g of Bi2O3 through the simple solution method using 99.9% isopropanol as a solution. This sample solution is stirred until homogeneous, then centrifuged. The precipitate was dried until a dry powder was obtained. The powder was analyzed using X-Ray fluorescence spectrometry to identify its chemical composition and concentration. A total of 30 samples were divided into two experimental groups of tricalcium silicate-WPC added Bi2O3 and ProRoot MTA. The vials, which contain cement and C. albicans, respectively, were incubated at 37°C for 24 hours and diluted to obtain a suspension 104, 106 (0.5 in McFarland’s nephelometer) and then inoculated with sterile cotton swabs onto Saboroud Dextrose Agar Plates. The plates were incubated at 37°C for 24 hours. The measurement of colony number of C. albicans was counted by colony counter (CFU/ml).

Results:

The Bi2O3 was revealed in tricalcium silicate-WPC based on XRF characterization, and the antifungal test showed that both materials were effective against C. albicans. There was no statistically significant difference in the number of C. albicans colonies between tricalcium-WPC added Bi2O3 and MTA (p>0.05).

Conclusion:

The mixture of Bi2O3 in tricalcium silicate-WPC was successfully fabricated through a simple solution method, and both samples were effective against the C. albicans.

Iodoform-Blended Portland Cement for Dentistry

Portland cement-based formulations blended with radiopacifying agents are popular endodontic materials for various root filling and pulp capping applications. Iodoform (CHI3) is an alternative candidate radiopacifier whose impact on the setting, bioactivity, antimicrobial properties and cytotoxicity of white Portland cement were evaluated in this study. Isothermal conduction calorimetry and 29Si magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR) showed that 20 wt% iodoform had no significant impact on the kinetics of cement hydration with respect to the formation of the major calcium silicate hydrate (C-S-H) gel product (throughout the 28-day observation). Conversely, transmission electron microscopy demonstrated that iodine was incorporated into the ettringite (Ca₆Al₂(SO₄)₃(OH)₁₂·26H₂O) product phase. Both iodoform-blended and pure Portland cements exhibited comparable biocompatibility with MG63 human osteosarcoma cells and similar bioactivity with respect to the formation of a hydroxyapatite layer upon immersion in simulated body fluid. By virtue of their high alkalinity, both cements inhibited the growth of Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. However, in all cases, iodoform enhanced the antimicrobial effect and significantly reduced the minimum bactericidal concentration of the cement. In conclusion, iodoform offers antimicrobial advantages in Portland cement-based formulations where oral biofilm formation threatens the success of root filling materials and dentine substitutes. The reactivity with the calcium aluminosulfate components of the hydrating cement matrix warrants further research to understand the long-term stability of the cement matrix in the presence of iodoform.

Dislodgement resistance and adhesive pattern of different endodontic sealers to dentine wall after artificial ageing: an in-vitro study

To compare the dislodgement resistance and the adhesive pattern of four different endodontic sealers to root dentine walls. Ninety lower premolars were assigned to five groups (n = 18), Group 1: no sealer (control); Group 2: EndoRez (ERZ); Group 3: Sealapex (SPX); Group 4: EndoSeal MTA (ESA) and Group 5: BioRoot RCS (BRS). They were instrumented up to size 30 taper 0.06 and obturated using single cone technique with matched-taper gutta-percha cones and one of the mentioned sealers. Six teeth from each group were then randomly subjected to 100, 1000 and 10,000 thermocycles, respectively. 1 mm slice of mid root region, measuring 6 mm from the apical foramen was prepared and subjected to push-out test under a Universal Testing Machine. Adhesive patterns of sealers were assessed using a stereomicroscope at 20 × magnification and classified using a new system. Statistical analyses were performed using two-way ANOVA, complemented by Tukey HSD and Chi-square tests. ESA and BRS showed significantly higher (p < 0.05) push-out bond strength, followed by SPX, ERZ and lastly the control, but no significant difference was noted between ESA and BRS (p > 0.05) at 100, 1000 and 10,000 thermocycles, respectively. Both ESA and BRS exhibited a significant higher rate (p < 0.05) of Type 3 and Type 4 adhesive patterns as the thermocycles increased. ESA and BRS demonstrated higher bond strength and better adhesive pattern to root dentine wall than SPX and ERZ, especially after artificial ageing.

Comparative Surface Morphology, Chemical Composition, and Cytocompatibility of Bio-C Repair, Biodentine, and ProRoot MTA on hDPCs

Biocompatibility is an essential property for any vital pulp material that may interact with the dental pulp tissues. Accordingly, this study aimed to compare the chemical composition and ultrastructural morphology of Biodentine (Septodont, Saint Maur-des-Fosses, France), ProRoot MTA (Dentsply Tulsa Dental Specialties, Johnson City, TN, USA), and Bio-C Repair (Angelus, Londrina, PR, Brazil), as well as their biological effects on human dental pulp cells. Chemical element characterization of the materials was undertaken using scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX). The cytotoxicity was assessed by analyzing the cell viability (MTT assay), cell morphology (immunofluorescence assay), and cell attachment (flow cytometry assay). The results were statistically analyzed using ANOVA and Tukey’s test (p < 0.05). EDX revealed that ProRoot MTA and Biodentine were mostly composed of calcium, carbon, and oxygen (among others), whereas Bio-C Repair evidenced a low concentration of calcium and the highest concentration of zirconium. SEM showed adequate attachment of human dental pulp cells (hDPCS) to vital pulp materials and cytoskeletal alterations were not observed in the presence of material eluates. Remarkably, the undiluted Biodentine group showed higher viability than the control group cells (without eluates) at 24 h, 48 h, and 72 h (p < 0.001). Based on the evidence derived from an in vitro cellular study, it was concluded that Bio-C Repair showed excellent cytocompatibility that was similar to Biodentine and ProRoot MTA.

Bio-Inductive Materials in Direct and Indirect Pulp Capping-A Review Article

The article is aimed at analyzing the available research and comparing the properties of bio-inductive materials in direct and indirect pulp capping procedures. The properties and clinical performances of four calcium-silicate cements (ProRoot MTA, MTA Angelus, RetroMTA, Biodentine), a light-cured calcium silicate-based material (TheraCal LC) and an enhanced resin-modified glass-ionomer (ACTIVA BioACTIVE) are widely discussed. A correlation of in vitro and in vivo data revealed that, currently, the most validated material for pulp capping procedures is still MTA. Despite Biodentine’s superiority in relatively easier manipulation, competitive pricing and predictable clinical outcome, more long-term clinical studies on Biodentine as a pulp capping agent are needed. According to available research, there is also insufficient evidence to support the use of TheraCal LC or ACTIVA BioACTIVE BASE/LINER in vital pulp therapy.

Biocompatibility of a New Antibacterial Compound and its Effect on the Mechanical Properties of Flowable Dental Composites (Animal Study)

STATEMENT OF THE PROBLEM

Recently, new compound of 3, 5-dimethyl-1-thiocarboxamide pyrazole has been composed with excellent antibacterial property. Biocompatibility and its effects on mechanical properties of dental composites should be considered before clinical use.

PURPOSE

The purpose of this study was to evaluate the biocompatibility of 3, 5-dimethyl-1-thiocarboxamide pyrazole as a new antibacterial compound and its effect on the mechanical properties of dental composites.

MATERIALS AND METHOD

In this experimental study, a new antibacterial compound was synthesis by reaction between Thiosemicarbazide and 2, 4-Pentandione and tested on thirty male albino Wistar rats weighting 200-250gr. Rats were randomly divided into 3 groups of 10, each rat received 3 implants of 3,5-dimethyl-1-thiocarboxamide pyrazole, penicillin v and empty polyethylene tube. A pathologist, who was unaware of types of tested materials and timing, performed the examination of specimens. The depth of cure and flexural strength of resin composite was measured using Iso4049 standard technique. Compressive strength was determined according to Iso9917 standard.

RESULTS

This compound was biocompatible and there was no significant difference in flexural strength and compressive strength of the composites containing 1% of this compound with the control group (p> 0.05).

CONCLUSION

The 3, 5-dimethyl-1-thiocarboxamide pyrazole with a concentration of 1% in flowable composites can be very effective in preventing secondary caries.

Effects of Milling Time, Zirconia Addition, and Storage Environment on the Radiopacity Performance of Mechanically Milled Bi2O3/ZrO2 Composite Powders

Mineral trioxide aggregate (MTA) typically consists of Portland cement (75 wt.%), bismuth oxide (20 wt.%), and gypsum (5 wt.%) and is commonly used as endodontic cement. Bismuth oxide serving as the radiopacifying material reveals the canal filling effect after clinical treatment. In the present study, bismuth/zirconium oxide composite powder was prepared by high energy ball milling of (Bi₂O₃)_100−x (ZrO₂)_x (x = 5, 10, 15, and 20 wt.%) powder mixture and used as the radiopacifiers within MTA. The crystalline phases of the as-milled powders were examined by the X-ray diffraction technique. The radiopacities of MTA-like cements prepared by using as-milled composite powders (at various milling stages or different amount of zirconia addition) were examined. In addition, the stability of the as-milled powders stored in an ambient environment, an electronic dry box, or a glove box was investigated. The experimental results show that the as-milled powder exhibited the starting powder phases of Bi₂O₃ and ZrO₂ and the newly formed δ-Bi_7.38Zr_0.62O_2.31 phase. The longer the milling time or the larger the amount of the zirconia addition, the higher the percentage of the δ-Bi_7.38Zr_0.62O_2.31 phase in the composite powder. All the MTA-like cements prepared by the as-milled powder exhibited a radiopacity higher than 4 mmAl that is better than the 3 mmAl ISO standard requirement. The 30 min as-milled (Bi₂O₃)₉₅(ZrO₂)₅ composite powder exhibited a radiopacity of 5.82 ± 0.33 mmAl and degraded significantly in the ambient environment. However, storing under an oxygen- and humidity-controlled glove box can prolong a high radiopacity performance. The radiopacity was 5.76 ± 0.08 mmAl after 28 days in a glove box that was statistically the same as the original composite powder.

Impact of Bi2O3 and ZrO2 Radiopacifiers on the Early Hydration and C-S-H Gel Structure of White Portland Cement

Bismuth oxide (monoclinic α-Bi₂O₃) and zirconium oxide (monoclinic ZrO₂) are the most popular radiopacifiers in commercial Portland cement-based endodontic restoratives, yet their effects on the setting and hydration reactions are not fully understood. This study compares the impact of 20 wt.% of Bi₂O₃ or ZrO₂ on the early hydration reactions and C–S–H gel structure of white Portland cement (WPC). Cement paste samples were hydrated at 37.5 °C prior to analysis by ²⁹Si and ²⁷Al magic angle spinning nuclear magnetic resonance spectroscopy at 3 h and 24 h, and transmission electron microscopy at 3 h. Initial and final setting times were determined using a Vicat apparatus and reaction kinetics were monitored by isothermal conduction calorimetry. Bi₂O₃ was found to prolong initial and final setting times and retard the degree of hydration by 32% at 24 h. Heat evolution during the acceleration and deceleration phases of the hydration process was reduced and the exotherm arising from renewed ettringite formation was delayed and diminished in the presence of Bi₂O₃. Conversely, ZrO₂ had no significant impact on either setting time; although, it accelerated hydration by 23% within 24 h. Increases in the mean silicate chain length and the extent of aluminum substitution in the C–S–H gel were observed in the presence of both radiopacifying agents after 24 h relative to those of the unblended WPC. The Bi₂O₃ and ZrO₂ particles remained intact within the cement matrix and neither bismuth nor zirconium was chemically incorporated in the hydration products.

Taguchi's methods to optimize the properties and bioactivity of 3D printed polycaprolactone/mineral trioxide aggregate scaffold: Theoretical predictions and experimental validation

Mineral trioxide aggregate (MTA) can provide bioactivity to poly-caprolactone (PCL), which is an inert polymer used to print scaffolds. However, testing all combinations of scaffold characteristics (e.g., composition, pore size, and distribution) to optimize properties of scaffolds is time-consuming and costly. The Taguchi's methods can identify characteristics that have major influences on the properties of complex designs, hence decreasing the number of combinations to be tested. The objective was to assess the potential of Taguchi's methods as a predictive tool for the optimization of bioactive scaffold printed using electro-hydro dynamic jetting. A three-level approach assessed the influence of PCL/MTA proportion, pore size, fiber dimension and number of layers in pH, degradation rate, porosity, yield strength, and Young's modulus. Data were analyzed using Tukey's honest significant difference test, analysis of mean and signal-to-noise ratio (S/N) test. Cytocompatibility and differentiation potential were assessed for 5 and 30 days using dental pulp stem cells and analyzed with one-way analysis of variance (proliferation) or Mann-Whitney (qPCR). The S/N ratio and analysis of mean showed that fiber diameter and composition were the most influential characteristics in all properties. The experimental data confirmed that the addition of MTA to PCL increased the pH and scaffold degradation. Only PCL and PCL with 4% MTA allowed cell proliferation. The latter increased the genetic expression of ALP, COL-1, OCN, and MSX-1. The theoretical predictions were confirmed by the experiments. The Taguchi's identified the inputs that can be disregarded to optimize 3D printed meshed bioactive scaffolds.

Influence of environment on testing of hydraulic sealers

In vitro material testing is undertaken by conducting a series of tests following procedures outlined in international standards. All material properties are measured in water; however biological behavior is undertaken in alternative media such as Dulbecco’s modified eagle medium (DMEM) or simulated body fluid. The aim of this study was to characterize four dental root canal sealers and study their properties in different media. Four dental root canal sealers were assessed. They were characterized by a combination of techniques and the sealer properties were tested as specified by ISO 6876 (2012) and also in alternative media. The sealer biocompatibility was measured by cell function and proliferation assays of elutions. All sealers complied with ISO specifications. The material properties were effected by the type of soaking medium used and the surface micromorphology and elemental composition were dependent on the soaking solution type. Both BioRoot and MTA Fillapex showed cytotoxicity which reduced at higher dilutions. The material chemistry, presentation, environmental conditions and testing methodology used affected the sealer properties. Standards specific to sealer type are thus indicated. Furthermore the methodology used in the standard testing should be more relevant to clinical situations.