Evaluation of cytotoxicity of MTA employing various additives

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.

Physicochemical, mechanical and biological properties of nano-calcium silicate-based cements: a systematic review

This systematic review evaluated the effects of nano-sized cement particles on the properties of calcium silicate-based cements (CSCs). Using defined keywords, a literature search was conducted to identify studies that investigated properties of nano-calcium silicate-based cements (NCSCs). A total of 17 studies fulfilled the inclusion criteria. Results indicated that NCSC formulations have favourable physical (setting time, pH and solubility), mechanical (push out bond strength, compressive strength and indentation hardness) and biological (bone regeneration and foreign body reaction) properties compared with commonly used CSCs. However, the characterization and verification for the nano-particle size of NCSCs were deficient in some studies. Furthermore, the nanosizing was not limited to the cement particles and a number of additives were present. In conclusion, the evidence available for the properties of CSC particles in the nano-range is deficient-such properties could be a result of additives which may have enhanced the properties of the material.

Clinical outcomes of non-surgical root canal obturations using NeoMTA: A retrospective series of case reports

NeoMTA is a commercially available tricalcium silicate-based cement intended for contact with pulp and periradicular tissues. The purpose of this study was to retrospectively evaluate the outcomes of non-surgical root canal treatments with NeoMTA obturations. Patients were treated in a private endodontic practice between 2015 and 2018. All cases, including initial treatments and retreatments, were either fully obturated with NeoMTA, or using gutta-percha with NeoMTA as an endodontic sealer. Outcomes were assessed using follow-up examination data with digital periapical radiographs with a minimum of a 1-year recall. Teeth were classified based on the clinical examination as: healed/healing (success), or non-healed (failure). 265 teeth were included with an average follow-up time of 1.3 years. The overall success rate was 91.7%. Only the presence of a pre-operative periapical radiolucency was found to significantly affect success. Comparison of obturation techniques demonstrated no effect on outcomes. NeoMTA is suitable for endodontic obturation.

Effects of Fucoidan Powder Combined with Mineral Trioxide Aggregate as a Direct Pulp-Capping Material

The development of direct pulp-capping materials with favorable biological and structural properties is an important goal in restorative dentistry. Fucoidan is a sulfated, fucose-containing polysaccharide obtained from brown seaweed, with a wide range of applications; however, its use as a direct pulp-capping material has not been examined. This study aimed to evaluate the mechanical, physical, and biological effects of fucoidan combined with conventional mineral trioxide aggregate (MTA) for direct pulp capping. The capping materials were created using Portland cement (80 wt%) and zirconium oxide (20 wt%) as base components, compared with base components plus 5 wt% fucoidan (PZF5) and base components plus 10 wt% fucoidan (PZF10). The initial and final setting time, compressive strength, chemical components, cell viability, adhesion, migration, osteogenesis, and gene expression were analyzed. Fucoidan significantly reduced the initial and final setting time, regardless of quantity. However, the compressive strength was lower for PZF5. Sulfur levels increased with fucoidan. The biological activity improved, especially in the PZF5 group. Cell migration, Alizarin Red S staining, and alkaline phosphatase activity were upregulated in the PZF5 group. Fucoidan is a useful regenerative additive for conventional pulp-capping materials because it reduces the setting time and improves cell migration and osteogenic ability.

Biocompatibility and Osteogenic Potential of Calcium Silicate-Based Cement Combined with Enamel Matrix Derivative: Effects on Human Bone Marrow-Derived Stem Cells

The characteristics of retrograde filling material are important factors that can affect the long-term success of apical microsurgery. Various calcium silicate-based cements (CSC) were introduced to overcome drawbacks of mineral trioxide aggregate (MTA), while Emdogain is known to be effective in the regeneration of periodontal tissues. The aim of this study is to evaluate the biocompatibility and osteogenic potential of various CSCs combined with Emdogain on human bone marrow-derived mesenchymal stem cells. Experimental groups were classified into eight groups depending on the material and the presence of Emdogain. In the cell-counting kit test, all experimental groups combined with Emdogain showed higher cell viability compared with those without Emdogain at days 1 and 2. In the wound-healing assay, cell migration increased significantly over time, with or without Emdogain. In the alkaline phosphatase assay, all groups treated with Emdogain showed higher activity compared with those without Emdogain at day 3 (p < 0.05). Using alizarin red S staining, all groups treated with Emdogain showed greater calcium nodule formation compared with those without Emdogain at days 7 and 14 (p < 0.05). In conclusion, using CSCs as retrograde filling materials and the application of additional Emdogain will increase bone regeneration and improve the prognosis of apical microsurgery.

Novel Fast-Setting Mineral Trioxide Aggregate: Its Formulation, Chemical-Physical Properties, and Cytocompatibility

One of the main drawbacks that limits the application of mineral trioxide aggregate (MTA) in dental field is its long setting time. Mineral trioxide aggregate with accelerated setting properties and excellent chemical-physical and biological properties is still required. In this study, an innovative mineral trioxide aggregate, which consists of calcium silicates, calcium aluminates, and zirconium oxide, was designed to obtain fast-setting property. The optimized formulation can achieve initial setting in 10 min and final setting in 15 min, which are much faster than commercial mineral trioxide aggregate. In addition, the optimized fast-setting MTA showed adequate radiopacity and good biocompatibility. The ion concentrations after storage in water for 1 day were 52.3 mg/L Ca, 67.7 mg/L Al, 48.8 mg/L Si, and 11.7 mg/L Mg. The hydration products of hardened cements were investigated by X-ray diffraction, scanning electron microscopy, and Fourier transform infrared, showing the accelerated setting time was due to the formation of honeycomb-like calcium silicate hydrate gel. The novel MTA could be a promising material for dental applications.

Mineral trioxide aggregate enriched with iron disulfide nanostructures: an evaluation of their physical and biological properties

The purpose of this study was to characterize mineral trioxide aggregates (MTA) enriched with iron disulfide (FeS₂ ) nanostructures at different concentrations, and to investigate their storage modulus, radiopacity, setting time, pH, cytotoxicity, and antimicrobial activity. Iron disulfide nanostructures [with particle size of 0.357 ± 0.156 μm (mean ± SD)] at weight ratios of 0.2, 0.4, 0.6, 0.8, and 1.0 wt% were added to white MTA (wMTA). The radiopacity, rheological properties, setting time, and pH, as well as the cytotoxicity (assessed using the MTT assay) and antibacterial activity (assessed using the broth microdilution test) were determined for MTA/FeS₂ nanostructures. The nanostructures did not modify the radiopacity values of wMTA (~6 mm of aluminium); however, they reduced the setting time from 18.2 ± 3.20 min to 13.7 ± 1.8 min, and the storage modulus was indicative of a good stiffness. Whereas the wMTA/FeS₂ nanostructures did not induce cytotoxicity when in contact with human pulp cells (HPCs) and human gingival fibroblasts (HGFs), they showed bacteriostatic activity against Staphylococcus aureus, Escherichia coli, and Enterococcus faecalis. Adding FeS₂ nanostructures to MTA might be an option for improving the root canal sealing and antibacterial effects of wMTA in endodontic treatments.

Effects of different radio-opacifying agents on physicochemical and biological properties of a novel root-end filling material

Background/Purpose

Radio-opacity is an essential attribute of ideal root-end filling materials because it is important for clinicians to observe root canal filling and to facilitate the follow-up instructions. The novel root-end filling material (NRFM) has good cytocompatibility and physicochemical properties but low intrinsic radio-opacity value. To improve its radio-opacity value, three novel radio-opaque root-end filling materials (NRRFMs) were developed by adding barium sulphate (NRFM-Ba), bismuth trioxide (NRFM-Bi) and zirconium dioxide (NRFM-Zr) to NRFM, respectively. The purpose of this study was to identify the suitable radio-opacifier for NRFM through evaluating their physicochemical and biological properties, in comparison with NRFM and glass ionomer cement (GIC).

Methods

NRRFMs were characterized using X-ray diffraction (XRD) and Fourier transform infrared spectrophotometry (FTIR). Physicochemical properties including setting time, compressive strength, porosity, pH variation, solubility, washout resistance, contact angle and radiopacity were investigated. Cytocompatibility of both freshly mixed and set NRRFMs was investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Alkaline phosphatase (ALP) activity assay and alizarin red staining were used to investigate the osteogenic differentiation potential of NRFM-Zr. Data were analyzed using two-way ANOVA (pH variation, solubility and ALP activity) and one-way ANOVA (for the other variables).

Results

(1) NRRFMs were primarily composed of hydroxyapatite, calcium carboxylate salt and the corresponding radio-opacity agents (barium sulphate, bismuth trioxide or zirconium dioxide). (2) Besides similar physicochemical properties in terms of setting time, pH variation, solubility, washout resistance and contact angle to NRFM, NRFM-Bi and NRFM-Zr exhibited lower porosity and greater compressive strength after being set for 7 days and their radio-opacity were greater than the 3 mm aluminium thickness specified in ISO 6876 (2001). (3) MTT assay revealed that freshly mixed and set NRFM-Zr presented better cell viability than NRFM-Ba and NRFM-Bi at 24 hours and 48 hours (P<0.05). (4) NRFM-Zr significantly enhanced ALP activity and calcium formation of human osteoblast-like Saos-2 cells when compared with negative group and GIC (P<0.05).

Conclusion

NRFM-Zr presents desirable physicochemical and biological properties, thus zirconium dioxide may be a suitable radio-opacifier for NRFM.

A Review Over Benefits and Drawbacks of Combining Sodium Hypochlorite with Other Endodontic Materials

INTRODUCTION

As the root canal system considered to be complex and unpredictable, using root canal irrigants and medicaments are essential in order to enhance the disinfection of the canal. Sodium hypochlorite is the most common irrigant in endodontics. Despite its excellent antimicrobial activity and tissue solubility, sodium hypochlorite lacks some important properties such as substantivity and smear layer removing ability.

OBJECTIVE

The aim of this review was to address benefits and drawbacks of combining sodium hypochlorite with other root canal irrigants and medicaments.

DISCUSSION

According to the reviewed articles, NaOCl is the most common irrigation solution in endodontics. However, it has some drawbacks such as inability to remove smear layer. One of the drawbacks of NaOCl is its inability to remove the smear layer and lack of substantivity.

CONCLUSION

The adjunctive use of other materials has been suggested to improve NaOCl efficacy. Nevertheless, further studies are required in this field.

White mineral trioxide aggregate mixed with calcium chloride dihydrate: chemical analysis and biological properties

OBJECTIVES

This study aimed to evaluate the chemical and biological properties of fast-set white mineral trioxide aggregate (FS WMTA), which was WMTA combined with calcium chloride dihydrate (CaCl₂·2H₂O), compared to that of WMTA.

MATERIALS AND METHODS

Surface morphology, elemental, and phase analysis were examined using scanning electron microscope (SEM), energy dispersive X-ray microanalysis (EDX), and X-ray diffraction (XRD), respectively. The cytotoxicity and cell attachment properties were evaluated on human periodontal ligament fibroblasts (HPLFs) using methyl-thiazol-diphenyltetrazolium (MTT) assay and under SEM after 24 and 72 hours, respectively.

RESULTS

Results showed that the addition of CaCl₂·2H₂O to WMTA affected the surface morphology and chemical composition. Although FS WMTA exhibited a non-cytotoxic profile, the cell viability values of this combination were lesser than WMTA, and the difference was significant in 7 out of 10 concentrations at the 2 time intervals (p < 0.05). HPLFs adhered over the surface of WMTA and at the interface, after 24 hours of incubation. After 72 hours, there were increased numbers of HPLFs with prominent cytoplasmic processes. Similar findings were observed with FS WMTA, but the cells were not as confluent as with WMTA.

CONCLUSIONS

The addition of CaCl₂·2H₂O to WMTA affected its chemical properties. The favorable biological profile of FS WMTA towards HPLFs may have a potential impact on its clinical application for repair of perforation defects.

The effect of accelerated mineral trioxide aggregate on odontoblastic differentiation in dental pulp stem cell niches

AIM

To investigate the effect of accelerated-set mineral trioxide aggregate (MTA) on the proliferation and odontoblastic differentiation of human dental pulp cell niches (DPSC).

METHODOLOGY

ProRoot White MTA (WMTA; Dentsply Tulsa Dental, Johnson City, TN, USA) was mixed with various additives, which included distilled water, 2.5% disodium hydrogen phosphate (Na₂ HPO₄ ; Merck, Darmstadt, Germany) and 5% calcium chloride (CaCl₂ ; Merck). DPSC niches extracted from third molars were cultured directly on MTA in the culture medium. Cell viability was evaluated by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4- sulphophenyl)-2H-tetrazolium (MTS) assay. Cell growth and expression of odontoblastic differentiation markers (dentine sialophosphoprotein (DSPP) and collagen type 1 (COL1)) were determined using Real-Time Polymerase Chain Reaction analysis. Osteo-/odontogenic differentiation of DPSC niches was evaluated by measurement of alkaline phosphatase activity (ALP). Calcium deposition was assessed using von Kossa staining. The results were analysed statistically using Mann-Whitney tests and Kruskal-Wallis tests.

RESULTS

MTA mixed with 5% CaCl₂ and 2.5% Na₂ HPO₄ exhibited optimal cell viability (P < 0.05) compared to MTA mixed with distilled water. MTA mixed with 5% CaCl₂ and 2.5% Na₂ HPO₄ significantly increased ALP activity (P < 0.05), significantly promoted mineralization nodule formation (P < 0.05) and significantly enhanced the mRNA expression level of the osteogenic/odontogenic markers (P < 0.05; DSPP and COL1) compared with MTA mixed with distilled water.

CONCLUSIONS

MTA mixed with 5% CaCl₂ and 2.5% Na₂ HPO₄ was biocompatible with dental pulp stem cell niches. Accelerated-set MTA promoted better differentiation in DPSC niches than conventional MTA. The accelerators could provide an alternative to MTA mixed with distilled water.

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.

Cytotoxic effects of mineral trioxide aggregate, calcium enrichedmixture cement, Biodentine and octacalcium pohosphate onhuman gingival fibroblasts

Background. This in vitro study compared the effects of mineral trioxide aggregate (MTA), calcium enriched mixture(CEM) cement, Biodentine (BD) and octacalcium phosphate (OCP) on the viability of human gingival fibroblasts (HGFs). Methods. After completion of the setting time of the materials under study, fibroblasts were placed in 24-well insert platesand 1 mg of each material was added to the respective wells. The plates were then incubated at 37°C. The inserts were removedat 24, 48 and 168 hours and 2,5-diphenyltetrazolium bromide was added to assess cytotoxicity via the MTT colorimetricassay. Data were analyzed at different time intervals using repeated-measures ANOVA, followed by the Bonferronitest at three levels of significance of P < 0.05, P < 0.01 and P < 0.001. Results. Cytotoxicity of the materials under study was not significantly different at 24 and 48 hours compared to the controlgroup. However, at 168 hours, a significant difference was noted between MTA (P < 0.05) and Biodentine (P < 0.01)and the control group. Conclusion. Cytotoxicity of MTA, CEM, Biodentine and OCP against HGFs was similar to that of the control group at 24and 48 hours. Over time, MTA and Biodentine exhibited less cytotoxicity than other materials.

In vitro toxicity of formocresol, ferric sulphate, and grey MTA on human periodontal ligament fibroblasts

AIM

This was to assess and compare the in vitro toxicity of formocresol, ferric sulphate and MTA on cultured human periodontal ligament (PDL) fibroblasts.

STUDY DESIGN

PDL cells were obtained from sound first permanent molars and cultured in Dulbecco's modified Eagle's medium.

METHODS

PDL cells were subjected to different concentrations of formocresol, ferric sulphate, and grey MTA for 24, 48, and 72 h at 37 °C. Cells that were not exposed to the tested materials served as the negative control. In vitro toxicity was assessed using MTT assay.

STATISTICS

Statistical analysis of data was accomplished using ANOVA and Tukey statistical tests (p<0.05).

RESULTS

The overall toxicity ranking of the tested materials was as follows: formocresol>ferric sulphate>grey MTA. Only grey MTA had comparable cell viability to the negative control, the other tested materials were significantly inferior at the three exposure periods (p<0.05).

CONCLUSION

Regarding the viability of PDL fibroblasts, MTA stands as the most promising substitute to formocresol. However, considering MTA's unavailability and high price in Jordan, ferric sulphate may be the best alternative to formocresol in pulpotomy of primary teeth.

Effect of additives on mineral trioxide aggregate setting reaction product formation

INTRODUCTION

Mineral trioxide aggregate (MTA) sets via hydration of calcium silicates to yield calcium silicate hydrates and calcium hydroxide (Ca[OH]2). However, a drawback of MTA is its long setting time. Therefore, many additives have been suggested to reduce the setting time. The effect those additives have on setting reaction product formation has been ignored. The objective was to examine the effect additives have on MTA's setting time and setting reaction using differential scanning calorimetry (DSC).

METHODS

MTA powder was prepared with distilled water (control), phosphate buffered saline, 5% calcium chloride (CaCl2), 3% sodium hypochlorite (NaOCl), or lidocaine in a 3:1 mixture and placed in crucibles for DSC evaluation. The setting exothermic reactions were evaluated at 37°C for 8 hours to determine the setting time. Separate samples were stored and evaluated using dynamic DSC scans (37°C→640°C at10°C/min) at 1 day, 1 week, 1 month, and 3 months (n = 9/group/time). Dynamic DSC quantifies the reaction product formed from the amount of heat required to decompose it. Thermographic peaks were integrated to determine enthalpy, which was analyzed with analysis of variance/Tukey test (α = 0.05).

RESULTS

Isothermal DSC identified 2 main exothermal peaks occurring at 44 ± 12 and 343 ± 57 minutes for the control. Only the CaCl2 additive was an accelerant, which was observed by a greater exothermic peak at 101 ± 11 minutes, indicating a decreased setting time. The dynamic DSC scans produced an endothermic peak around 450°C-550°C attributed to Ca(OH)2 decomposition. The use of a few additives (NaOCl and lidocaine) resulted in significantly less Ca(OH)2 product formation.

CONCLUSIONS

DSC was used to discriminate calcium hydroxide formation in MTA mixed with various additives and showed NaOCl and lidocaine are detrimental to MTA reaction product formation, whereas CaCl2 accelerated the reaction.

An early and late cytotoxicity evaluation of lidocaine on human oral mucosa fibroblasts

Local anesthetic drugs are extensively used in dentistry. However, the cytotoxic effects of these pharmaceutical compounds remain unclear. In this work, we have evaluated the cell viability and cell function of human oral mucosa fibroblasts exposed to different concentrations of lidocaine for increasing incubation times, using a global screening methods including structural, metabolic and microanalytical analyses. Our results demonstrate that lidocaine is able to alter cell viability and function even at low concentrations and times, although the effect of lidocaine concentration was more important than the incubation time. First, the structural analysis methods revealed that ≥5% concentrations of lidocaine are able to significantly reduce cell viability. Then, the metabolic 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and water-soluble tetrazolium salt (WST-1) assays suggest that concentrations starting from 1% were able to significantly hinder cell physiology. Finally, electron-probe X-ray microanalysis confirmed the deleterious effects of lidocaine and allowed us to demonstrate that these effects are associated to an apoptosis process of cell death. Therefore, care should be taken when lidocaine is clinically used, and the lowest efficient concentrations should always be used. Furthermore, these results suggest that the comprehensive evaluation method used in this work is accurate and efficient for screening of local anesthetics.

Effects of two low-shrinkage composites on dental stem cells (viability, cell damaged or apoptosis and mesenchymal markers expression)

To investigate the effects of new two low-shrinkage composites SDR(®) and Venus(®)Bulk Fill on the cell viability, cellular damage and expression of mesenchymal markers on dental stem cells. Specimens from two low-shrinkage composites were eluted with culture medium for 24 h. After 24 h of incubation, cytotoxicity of elutes were evaluated by MTT assay; apoptosis was determined using the DNA-specific fluorochrome Hoechst 33342 and the mesenchymal stem cells markers expression was analyzed by immunofluorescence staining. After 24 h of cell exposure to each extract media, dental stem cells expressed MSCs markers. The interaction among the material and cell line was not significantly correlated [F(1,60) = 2.251, P = 0.39], whereas statistically significant differences among cells lines were observed [F(1,60) = 9.157, P = 0.004], being dental pulp stem cells more resistant that periodontal ligament stem cells. Also, we did not find any significant effect between the tested materials [F(1,60) = 0.090, P = 0.765]. Furthermore, a very low proportion of exposed cells showed condensed or fragmented nuclei, typical of apoptotic cells at 24 h. The results suggest that SDR(®) and Venus(®) Bulk fill and should be considered when selecting an appropriate resin-based dental restorative material.

Effect of Goji (Lycium barbarum) on expression of genes related to cell survival

This study investigated the interrelationship between Lycium barbarum (goji) and gene expression in mouse spleen. Oligomicroarray technology was employed to explore the comprehensive response of gene expression and to screen candidate marker genes in the spleens of mice fed a goji suspension. Goji was micronized by media milling and then used to evaluate the effect of size reduction. The average diameter of nano/submicrometer goji was about 100 nm, which exhibited no cytotoxicity to cell lines IEC-6 (rat normal small intestinal cell line) and Caco-2 (human colon adenocarcinoma cell line). It was found that three genes, TNF, Nfkb1, and Bcl-2, were up-regulated and two genes, APAF-1 and caspase-3, were down-regulated by goji. This phenomenon could be helpful for cytoprotection when cells undergo stress or damage that induces the apoptotic pathway. Size reduction into nano/submicrometer scale enhanced bioactivity.

Effect of selected accelerants on setting time and biocompatibility of mineral trioxide aggregate (MTA)

OBJECTIVE

Various additives have been suggested to be used with mineral trioxide aggregate (MTA) to improve its handling characteristics. The purpose of this study was to evaluate the effects of various additives on setting time and cell attachment on gray MTA (GMTA).

STUDY DESIGN

Single-rooted caries-free teeth were split, and dentin disks with class I cavity were made and filled with test and control materials. Setting time was measured using Gilmore apparatus. Mouse MC3T3-E1 osteoblasts and L929 mouse fibroblasts were grown on dentin and GMTA disks. Cell attachment was examined under fluorescent microscope.

RESULTS

Adding KY liquid, CaCl(2), and NaOCl to GMTA improved the handling properties and decreased setting time. Osteoblasts and fibroblasts attached and spread on GMTA mixed with additives in a manner similar to GMTA mixed with water.

CONCLUSIONS

The various additives could be possible substitutes to water to decrease MTA setting time. MTA is biocompatible when mixed with the various additives.

"MTA"-an Hydraulic Silicate Cement: review update and setting reaction

OBJECTIVES

To review the current status and understanding of Portland cement-like endodontic materials commonly referred to by the trade designation "MTA" (alias "Mineral Trioxide Aggregate"), and to present an outline setting reaction scheme, hitherto unattempted.

METHOD

The literature was searched using on-line tools, overlapping an earlier substantial review to pick up any omissions, including that in respect of ordinary Portland cement (OPC), with which MTA shares much. The search was conducted for the period January 2005 to December 2009 using 'MTA', 'GMTA', 'WMTA', and 'mineral AND trioxide AND aggregate' as keywords, with various on-line search engines including ScienceDirect (http://www.sciencedirect.com), SAGE Journals Online (http://online.sagepub.com), Wiley Online Library (http://onlinelibrary.wiley.com), SciELO Scientific electronic library online (http://www.scielo.br/scielo.php), JSTOR (http://www.jstor.org), and Scopus (http://www.scopus.com). References of articles found were cross-checked where appropriate for missed publications. Manufacturers' and related websites were searched with Google Search (http://www.google.com.hk).

RESULTS

A generic name for this class of materials, Hydraulic Silicate Cement (HSC), is proposed, and an outline reaction scheme has been deduced. HSC has distinct advantages apparent, including sealing, sterilizing, mineralizing, dentinogenic and osteogenic capacities, which research continues to demonstrate. However, ad hoc modifications have little supporting justification.

SIGNIFICANCE

While HSC has a definite place in dentistry, with few of the drawbacks associated with other materials, some improvements in handling and other properties are highly desirable, as are studies of the mechanisms of the several beneficial physiological effects. Reference to the extensive, but complex, literature on OPC may provide the necessary insight.