Comparative chemical study of MTA and portland cements

Evaluation of Cytotoxic Effect of Graphene Oxide Added to Mineral Trioxide Aggregate

Aim:

Recently, although studies have shown that biomaterials containing graphene oxide (GO) in biomedicine stand out for their positive effects, the effect of GO on dental tissues when used with dental materials is not well known. The aim of this study was an evaluation of the cytotoxic effects of GO on gingival fibroblasts when it is combined in two different ratios with Mineral Trioxide Aggregate (MTA).

Materials and Methods:

In this in-vitro study, a homogenous mixture of adding +0.1 weight (wt)% and +0.3 wt% GO to Angelus MTA was created (two experimental groups) and compared with pure Angelus MTA and negative control groups. The materials were mixed according to the manufacturer’s instructions, and Teflon molds were used to form 24 disc-shaped samples for each group. The samples were divided into groups according to the simple random sampling method. The cytotoxic effect of samples was determined on gingival fibroblast cells by using the MTT test, and total oxidant status (TOS) and total antioxidant capacity (TAC) kits in 24 and 72 hours. The data were statistically analyzed using one-way ANOVA and Tukey tests.

Results:

A significant difference was found between the material-applied groups and the control group at the TAC 24 and 72 hours and between the groups containing GO and the control group at the MTT 72 hours and TAC and TOS 24 and 72 hours ( p < .05).

Conclusion:

The addition of GO to MTA increased the dose and time-based toxicity and oxidant amount, and decreased antioxidant capacity.

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

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

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.

Chitosan-Based Accelerated Portland Cement Promotes Dentinogenic/Osteogenic Differentiation and Mineralization Activity of SHED

Calcium silicate-based cements (CSCs) are widely used in various endodontic treatments to promote wound healing and hard tissue formation. Chitosan-based accelerated Portland cement (APC-CT) is a promising and affordable material for endodontic use. This study investigated the effect of APC-CT on apoptosis, cell attachment, dentinogenic/osteogenic differentiation and mineralization activity of stem cells from human exfoliated deciduous teeth (SHED). APC-CT was prepared with various concentrations of chitosan (CT) solution (0%, 0.625%, 1.25% and 2.5% (w/v)). Cell attachment was determined by direct contact analysis using field emission scanning electron microscopy (FESEM); while the material extracts were used for the analyses of apoptosis by flow cytometry, dentinogenic/osteogenic marker expression by real-time PCR and mineralization activity by Alizarin Red and Von Kossa staining. The cells effectively attached to the surfaces of APC and APC-CT, acquiring flattened elongated and rounded-shape morphology. Treatment of SHED with APC and APC-CT extracts showed no apoptotic effect. APC-CT induced upregulation of DSPP, MEPE, DMP-1, OPN, OCN, OPG and RANKL expression levels in SHED after 14 days, whereas RUNX2, ALP and COL1A1 expression levels were downregulated. Mineralization assays showed a progressive increase in the formation of calcium deposits in cells with material containing higher CT concentration and with incubation time. In conclusion, APC-CT is nontoxic and promotes dentinogenic/osteogenic differentiation and mineralization activity of SHED, indicating its regenerative potential as a promising substitute for the commercially available CSCs to induce dentin/bone regeneration.

A Comparative Study of Biocompatibility in Rat Connective Tissue of a New Mineral Trioxide Compound (Theracal) versus MTA and a Bioactive G3 Glass

The aim of this paper was to assess the differences in tissue response to implantation during 15, 30 and 45 days in the subcutaneous connective tissue of Wistar rats from three biomaterials: Angelus MTA^®, Theracal LC^®, and Angelus MTA^® to which 25% bioglass G3 was added. Twenty-four Wistar rats were used, the materials were inserted into the rat’s dorsal area in silicone tubes 5 mm long by 1.5 mm diameter. Histological reaction was assessed at 15, 30, and 45 days after implantation. They were then stained with hematoxylin eosin and evaluated by two observers. Data were analyzed using Fisher’s exact test and Mann–Whitney’s U test was used to determine the association between variables. Angelus MTA induced the formation of dystrophic calcifications twice as much as Theracal LC (p < 0.05). The addition of G3 did not affect the greater or lesser occurrence of calcifications (p > 0.05). Theracal LC and MTA plus G3 caused an inflammatory reaction, which was chronic at 15 days and decreased in intensity, almost disappearing after 45 days. Theracal LC, as well as Angelus MTA plus G3, were well tolerated when implanted in the subcutaneous connective tissue of rat. Histologically, no inconvenience was found for the use by direct contact of Theracal LC, and the mixture of MTA with 25% bioactive glass G3, in the tissue of Wistar rats.

The Effect of Calcium-Silicate Cements on Reparative Dentinogenesis Following Direct Pulp Capping on Animal Models

Dental pulp vitality is a desideratum for preserving the health and functionality of the tooth. In certain clinical situations that lead to pulp exposure, bioactive agents are used in direct pulp-capping procedures to stimulate the dentin-pulp complex and activate reparative dentinogenesis. Hydraulic calcium-silicate cements, derived from Portland cement, can induce the formation of a new dentin bridge at the interface between the biomaterial and the dental pulp. Odontoblasts are molecularly activated, and, if necessary, undifferentiated stem cells in the dental pulp can differentiate into odontoblasts. An extensive review of literature was conducted on MedLine/PubMed database to evaluate the histological outcomes of direct pulp capping with hydraulic calcium-silicate cements performed on animal models. Overall, irrespective of their physico-chemical properties and the molecular mechanisms involved in pulp healing, the effects of cements on tertiary dentin formation and pulp vitality preservation were positive. Histological examinations showed different degrees of dental pulp inflammatory response and complete/incomplete dentin bridge formation during the pulp healing process at different follow-up periods. Calcium silicate materials have the ability to induce reparative dentinogenesis when applied over exposed pulps, with different behaviors, as related to the animal model used, pulpal inflammatory responses, and quality of dentin bridges.

In vitro comparison of physical, chemical, and mechanical properties of graphene nanoplatelet added Angelus mineral trioxide aggregate to pure Angelus mineral trioxide aggregate and calcium hydroxide

It is important to cover the pulp surface with a biocompatible material that is physically, mechanically, and chemically adequate. Graphene has the potential to form hard tissue, but at high doses, it shows toxic effects. It can be added to biocompatible materials at low doses to enhance their hard tissue forming potential. The aim of this study was to compare the physical, chemical, and mechanical properties of graphene nanoplatelet (GNP) added Angelus mineral trioxide aggregate (A-MTA) to pure A-MTA and calcium hydroxide. Homogeneous mixtures (created by adding +0.1 weight[wt]% and 0.3 wt% GNP to A-MTA), pure A-MTA, and Dycal were used. Three disc-shaped samples of each material were prepared using Teflon mold. Scanning electron microscope-energy dispersive X-ray (SEM-EDX), particle size, microhardness, and Fourier transform infrared spectroscopy (FTIR) analysis of the materials were performed in vitro. Data were analyzed using Kruskal-Wallis test followed by Conover test (p < .001). A-MTA and GNP added samples showed similar peaks in FTIR analysis. In the EDX analysis, the amount of carbon was observed with a higher increase at A-MTA + 0.3 wt% GNP than A-MTA + 0.1 wt% GNP. In the SEM image, hollow structure and particle size decreased as the amount of GNP increased; particle size was smaller at A-MTA + 0.3 wt% GNP than A-MTA + 0.1 wt% GNP (p < .001). A-MTA + 0.3 wt% GNP showed the highest microhardness while Dycal showed the lowest microhardness. The addition of GNP, a material with high potential for forming hard tissue, to the structure of capping materials can also positively contribute to the microhardness of the capping materials.

The Hormetic Effect of Arsenic Trioxide on Rat Pulpal Cells: An In Vitro Preliminary Study

Objectives  Despite the agreement that there is no longer any indication for arsenic use in modern endodontics, some concerns are surfacing about the minute amount of arsenic trioxide (As ₂ O ₃ ) released from Portland cement-based materials. The present study investigated the effect of different concentrations of As ₂ O ₃ on rat pulpal cells and the efficacy of N -acetylcysteine (NAC) in preventing As ₂ O ₃ -mediated toxicity.

Materials and Methods  Cytotoxicities of 50, 10, or 5 µm As ₂ O ₃ and the effect of cells co-treatment with 50 µm As ₂ O ₃ and 5,000 µm NAC or 500 µm NAC were tested at 24 hours or 3 days. Cell viability was assessed by means of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and cellular morphological changes were observed under phase contrast microscope.

Statistical Analysis  Two-way analysis of variance with Tukey’s post-hoc test was used to evaluate differences between the groups (α = 0.05).

Results  At both exposure times, 50 µm As ₂ O ₃ resulted in lower optical density (OD) values when compared with 10 or 5 µm As ₂ O ₃ . At 24 hours, 10 µm As ₂ O ₃ resulted in a higher OD value compared with the control; however, at 3 days the difference was statistically insignificant. At each exposure time, the OD value of 5 µm As ₂ O ₃ group was comparable to the control and 10 µm As ₂ O ₃ group. There were no significant differences between 50 µm As ₂ O ₃ group and 500 μm NAC+50 μm As ₂ O ₃ group; however, these two groups had lower OD values when compared with 5,000 μm NAC+50 μm As ₂ O ₃ group at 24 hours and 3 days. The latter group showed significantly lower OD value in comparison with the control at 24 hours and 3 days. Control cells were polygonal-shaped while 50 µm As ₂ O ₃ -treated cells exhibited contracted and spherical morphology with increased intercellular spaces. At 24 hours, 10 μm and 5 µm As ₂ O ₃ -treated cells were slightly hypertrophic. Cells co-treated with NAC and As ₂ O ₃ showed increased intercellular spaces and lower cellular density compared with the control.

Conclusions  As ₂ O ₃ displayed a hormetic effect on pulpal cells; however, the proliferative effect induced by low As ₂ O ₃ concentrations should be interpreted with caution. NAC did not prevent As ₂ O ₃ -mediated toxicity; however, it demonstrated potential for ameliorating this toxicity.

A Bibliometric Analysis of Articles Published in Brazilian Dental Journal over 30 years

This study assessed bibliometric characteristics of all articles published in Brazilian Dental Journal (BDJ) in its 30 years of existence (1990-2019) and factors associated with citation rates. A document search was carried out in Scopus in December, 2019 and information about the articles were exported, including citations. Type of study and main subject in each article were categorized. Number of citations was categorized in tertiles. Logistic regression models were used to assess the association between variables related to articles' characteristics and number of citations. In 30 years, 1705 articles were published and 18507 citations received, with average 57 articles and 334 pages published yearly and 10.9 cites/doc. The most frequent types of study were laboratorial (63%), clinical (18.5%), and case reports (11%); the main subjects were dental materials (21.6%), endodontics (19.3%), and oral pathology/stomatology (13.1%). Most articles had origin in Brazil (90%), followed by USA (4.6%) and UK (1.5%). Aside from BDJ, Journal of Endodontics (3.5%) and International Endodontic Journal (2.2%) were journals that most often cited BDJ. Main origins of citations were Brazil (36.7%), USA (10.6%), and India (9%). Older articles had higher odds to be highly cited (12% increase/year), longer articles had lower odds (9% decrease/page). Narrative reviews and epidemiological studies were associated with more citations and systematic reviews with less citations. In conclusion, BDJ covered many subjects and study types in 30 years, showing increased growth in international audience. The journal may be regarded as one of the leading Brazilian journals in dentistry published in English.

The Contribution of the Brazilian Dental Journal to the Brazilian Scientific Research over 30 Years

The Brazilian Dental Journal (BDJ) was officially launched in 1990, stimulated by the courage and boldness of researchers dedicated to teaching and research in dentistry. The journal was conceived in a worldwide coverage and universal language to allow publication of the results of Brazilian studies, which otherwise would not be accessible to the scientific dental community. In the year we celebrate the thirtieth anniversary of BDJ, this article presents a brief overview of Brazilian dental research and a bibliometric analysis of the articles published in this journal as a contribution to our readers and fellow researchers. The purpose was to identify the mot frequent categories of study, the most published areas of dentistry and BDJ's top 50 most-cited articles in the Scopus and Google Scholar databases. A search was performed on all BDJ online issues published from 1990 to 2019. In this period, BDJ published 1,710 articles. Based on their distribution by category of study, 557 articles were in the basic research/dental materials area, 527 in the basic research/biology area and 280 in the clinical research area. Eight articles were cited more than 100 times in the Scopus database and 266 times in the Google Scholar database. Endodontics was the most published area. This overview of BDJ production over those 30 years allows establishing a profile of the characteristics, impact and trends of the published studies, as well as the journal's contribution to the top 50 most-cited articles in the Scopus and Google Scholar databases.

Experimental furcal perforation treated with mineral trioxide aggregate plus selenium: immune response

The aim of this study is to evaluate the expression of cytokines in response to mineral trioxide aggregate (MTA) plus selenium in germ-free mice with experimental furcal perforation. The first left maxillary molar was opened, and the furcal area was perforated and treated with post-MTA-Se (experimental group). The same surgical intervention was performed for the maxillary right first molar, which was treated with MTA (control group). Fifteen mice were sacrificed 7, 14, and 21 days after furcal perforation, and periapical tissue samples were collected. The mRNA expression levels of the cytokines TGF-β, TNF-α, IFN-γ, HPRT, IL-10, IL-4, RANK, RANKL, IL-1, and IL-17 were assessed by using real-time polymerase chain reaction. In the experimental group, at 21-days post-MTA-Se sealing, the mRNA levels of TNF-α and IL-10 were upregulated compared with those in the control group (p < 0.05). Futher assessment revealed basal mRNA expression levels of IL-1α, IFN-γ, RANK, RANKL, IL-17A, IL-4, and TGF-β, over long experimental times, in both the experimental and control groups (p > 0.05). In conclusion, MTA+Se sealing favoured increased expression of IL-10 and TNF-α at later time points (day 21).

In vivo biocompatibility and biomineralization of calcium silicate cements

A new mineral trioxide aggregate (MTA) material has been developed with a modified composition that requires investigations to support its clinical use. This study evaluated the biocompatibility and biomineralization of this new MTA material and compared it with that of two other MTA cements over time. Tubes containing materials (or empty tubes as controls) were inserted into the subcutaneous tissues of 40 rats. On days 7, 15, 30, 60, and 90, the tubes were removed with the surrounding tissues, which were either stained with haematoxylin and eosin or von Kossa for further analyses or unstained for observation under polarized light. On days 7 and 15, moderate inflammation was observed in most specimens, and the fibrous capsule was thick. On day 30, there was mild inflammation in all groups, and the fibrous capsule was thin. On days 60 and 90, there was mild inflammation in the material groups, while the control group showed no inflammation, although no statistically significant difference between the groups was observed and the fibrous capsule was thin. All material groups showed structures that stained with von Kossa and could be observed under polarized light; this was not found for the control. In conclusion, the new MTA material had biocompatibility and biomineralization properties similar to those of the two existing MTA materials.

The physical properties and ion release of CPP-ACP-modified calcium silicate-based cements

BACKGROUND

This study investigated the physical properties and ion release of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)-modified calcium silicate-based cements (CSCs) and compared the properties of a trial mineral trioxide aggregate (MTA) with two commercially available CSCs, Biodentine(™) and Angelus(®) MTA.

METHODS

The setting time, solubility, compressive strength and Vickers surface microhardness of the three CSCs incorporated with 0%, 0.5%, 1.0%, 2.0% and 3.0% (w/w) CPP-ACP were investigated. Release of calcium (Ca(2+) ), phosphate ions (Pi ) and pH of the test cements were measured after 24, 72, 168 and 336 h of storage.

RESULTS

The addition of up to 1.0% CPP-ACP into Biodentine(™) and 0.5% into the other cements did not adversely affect their physical properties except for the setting time. The addition of 0.5% CPP-ACP increased Ca(2+) released from Biodentine(™) (after 168 and 336 h), Angelus(®) MTA (after 168 h) and the trial MTA (after 72 h). The addition of 1.0-3.0% CPP-ACP increased Ca(2+) and Pi released from all the cements. Biodentine(™) released more Ca(2+) particularly in the early stages and showed shorter setting time and higher mechanical properties than the other cements. The mechanical properties of Angelus(®) MTA and the trial MTA were similar. All the cements produced highly alkaline storage solutions.

CONCLUSIONS

Up to 1.0% CPP-ACP in Biodentine(™) improves Ca(2+) and Pi release and 0.5% CPP-ACP in Angelus(®) MTA and the trial MTA improves Ca(2+) release without altering the mechanical properties and solubility. The addition of CPP-ACP into CSCs prolonged the setting time.

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.

Cytotoxicity and Bioactivity of Calcium Silicate Cements Combined with Niobium Oxide in Different Cell Lines

Abstract The aim of this study was to evaluate the cytotoxicity and bioactivity of calcium silicate-based cements combined with niobium oxide (Nb2O5) micro and nanoparticles, comparing the response in different cell lines. This evaluation used four cell lines: two primary cultures (human dental pulp cells - hDPCs and human dental follicle cells - hDFCs) and two immortalized cultures (human osteoblast-like cells - Saos-2 and mouse periodontal ligament cells - mPDL). The tested materials were: White Portland Cement (PC), mineral trioxide aggregate (MTA), white Portland cement combined with microparticles (PC/Nb2O5µ) or nanoparticles (PC/Nb2O5n) of niobium oxide (Nb2O5). Cytotoxicity was evaluated by the methylthiazolyldiphenyl-tetrazolium bromide (MTT) and trypan blue exclusion assays and bioactivity by alkaline phosphatase (ALP) enzyme activity. Results were analyzed by ANOVA and Tukey test (a=0.05). PC/Nb2O5n presented similar or higher cell viability than PC/Nb2O5µ in all cell lines. Moreover, the materials presented similar or higher cell viability than MTA. Saos-2 exhibited high ALP activity, highlighting PC/Nb2O5µ material at 7 days of exposure. In conclusion, calcium silicate cements combined with micro and nanoparticles of Nb2O5 presented cytocompatibility and bioactivity, demonstrating the potential of Nb2O5 as an alternative radiopacifier agent for these cements. The different cell lines had similar response to cytotoxicity evaluation of calcium silicate cements. However, bioactivity was more accurately detected in human osteoblast-like cell line, Saos-2.

Influence of powder composition and morphology on penetration of Gray and White ProRoot mineral trioxide aggregate and calcium hydroxide into dentin tubules

This study examined the influence of powder composition and morphology on the penetration of Gray and White ProRoot mineral trioxide aggregate (GMTA, WMTA) and calcium hydroxide (CH) into open dentin tubules. GMTA, WMTA, and CH particle dimensions were analyzed by flow particle image analysis (FPIA). Penetration of open dentin tubules into dentin discs was studied by scanning electron microscopy. Five samples of each material were randomly selected and prepared for this study. The GMTA averages for length (μm), width (μm), perimeter (μm), and aspect ratio were 1.94 ± 1.65, 1.43 ± 1.19, 5.61 ± 4.27, and 0.76 ± 0.14, respectively. Corresponding averages for WMTA were 2.04 ± 1.87, 1.49 ± 1.33, 5.88 ± 4.81, and 0.76 ± 0.14, and for CH were 2.26 ± 1.99, 1.62 ± 1.46, 6.70 ± 5.60, and 0.74 ± 0.15, respectively. The rank order of the averages for particle length, width and perimeter from the largest to the smallest material was CH > WMTA > GMTA. The rank order of the averaged aspect ratios was GMTA > WMTA > CH. SEM showed that all three materials, when deposited and agitated on dentin discs, penetrated the open dentin tubules. Tubule occlusion occurred as particle surface concentrations increased. Significant differences in particle length, width, perimeter, and aspect ratio were observed for GMTA, WMTA, and CH (P < 0.0001 in all cases). All particle types penetrated into open tubules when agitated on dentin discs; all tubules were eventually occluded as particle concentrations grew. (J Oral Sci 56, 287-293, 2014).

The use of bioceramics in endodontics - literature review

BACKGROUND AND AIM

Bioceramics are ceramic compounds obtained both in situ and in vivo, by various chemical processes. Bioceramics exhibit excellent biocompatibility due to their similarity with biological materials, like hydroxyapatite. Bioceramics and multi-substituted hydroxyapatite or similar compounds have the ability to induce a regenerative response in the organism. The aim of this paper is to make a literature review on the main bioceramic materials currently used in endodontics and on their specific characteristics.

METHODS

We conducted a search in the international databases (PubMed), to identify publications in the last 10 years, using the following key words: "bioceramics endodontics", "bioceramic endodontic cement", "bioceramic sealer" and "direct pulp capping bioceramic".

RESULTS

Commonly used endodontic sealers (e.g., containing zinc oxide, calcium hydroxide and a resin) have a long tradition in scientific research and clinical use in endodontics. For specific cases, like root resorptions, perforations, apexification, and retrograde fillings, new biocompatible materials were developed in order to improve the clinical outcome: ProRooT MTA (Dentsply Company, Germany); Biodentine (Septodont, France); Endosequence BC sealer (Brassler, SUA); Bioaggregate (IBC, Canada); Generex A (Dentsply Tulsa Dental Specialties, USA).

CONCLUSION

The studies are generally in favor of bioceramic materials even if there are not many products available on the market for endodontic use. As more products are launched and more research is performed regarding these materials, we will provide more reliable data on clinical outcome.

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

Background

Mineral trioxide aggregate (MTA) is a biomaterial that has been investigated for endodontic applications. With the increased use of MTA in pulp capping, pulpotomy, perforation repair, apexification and obturation, the material that would be placed over MTA as a final restoration is an important matter. As composite resins are one of the most widely used final restorative materials, this study was conducted to evaluate the shear bond strength of a composite resin to white mineral trioxide aggregate (WMTA) using three different bonding systems namely the two-step etch and rinse adhesive, the self-etching primer and the All-in-one system.

Material and Methods

Forty five specimens of white MTA (Angelus) were prepared and randomly divided into three groups of 15 specimens each depending on the bonding systems used respectively. In Group A, a Two-step etch and rinse adhesive or ‘total-etch adhesive’, Adper Single Bond 2 (3M/ESPE) and Filtek Z350 (3M ESPE, St Paul, MN) were placed over WMTA. In group B, a Two-step self-etching primer system, Clearfil SE Bond (Kuraray, Medical Inc) and Filtek Z350 were used. In Group C, an All-in-one system, G Bond (GC corporation, Tokyo, Japan) and Filtek Z350 were used. The shear bond strength was measured for all the specimens. The data obtained was subjected to One way Analysis of Variance (ANOVA) and Scheffe’s post hoc test.

Results

The results suggested that the Two-step etch and rinse adhesive when used to bond a composite resin to white MTA gave better bond strength values and the All-in-one exhibited the least bond strength values.

Conclusions

The placement of composite used with a Two-step etch and rinse adhesive over WMTA as a final restoration may be appropriate.

Key words:Composite resins, dentin bonding agents, mineral trioxide aggregate, shear bond strength.

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.

Cytotoxicity of two available mineral trioxide aggregate cements and a new formulation on human gingival fibroblasts

Aim:

The purpose of this study was to investigate the cytotoxicity of nanohybrid mineral trioxide aggregate (MTA) in comparison with calcium-enriched mixture (CEM) cement and MTA-Angelus, using human gingival fibroblasts (HGFs).

Materials and Methods:

Nine disc-shaped specimens of each material (in 2 set stat: A, set for 24 h; B, set for 30 min; and C, fresh stat) were prepared. HGFs were exposed to tested materials’ extracts or control media. Cytotoxicity testing was performed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay in two time intervals.

Statistical Analysis:

Results were evaluated by one-way ANOVA and t-test. Statistical significance was set at P < 0.05.

Results:

CEM cement demonstrated favorable cell viability values when completely set (24 h set MTA = 24 h set CEM) at both time intervals. Interestingly, 24 h after incubation, CEM in Groups B and C demonstrated higher cell viability values than MTA (P < 0.05). However, after 72 h of incubation, these groups of CEM and MTA showed equal cell viability. All samples of nanohybrid MTA had slight cytotoxic effects after 24 h of incubation, and moderate cytotoxic effects after 72 h of incubation.

Conclusion:

Set CEM and set MTA-Angelus exerted similar, favorable effects on cell viability. However, within the limitations of this in vitro study, the results suggest that nanohybrid MTA could not be recommended as a material of choice for cervical root resorption.

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.

Frequently asked questions in direct pulp capping of permanent teeth

Direct pulp capping is a proven method of preserving tooth vitality of a mature permanent tooth in cases of pulp exposures. The indications for this treatment, treatment modalities and materials are discussed in this paper.

CLINICAL RELEVANCE

This paper answers many of the frequently asked questions by general practitioners, dental students and specialists about direct pulp capping.

X-ray diffraction analysis of MTA-Plus, MTA-Angelus and DiaRoot BioAggregate

Objective:

The purpose of this study was to investigate and compare the crystalline structures of recently released MTA Plus (MTA-P), MTA Angelus (MTA-A), DiaRoot BioAggregate (BA) by X-ray diffraction (XRD) analysis.

Materials and Methods:

Phase analysis was carried out on powder and set forms of tested materials. The powder specimens placed into sample holders that were packed with a glass slide and the set samples prepared according to the manufacturer's instructions were placed into molds. The samples after being set for three days at 37°C and 100% humidity in an incubator were mounted onto the XRD machine and phase identification was accomplished using a search-match software program.

Results:

XRD findings indicated that major constituents of MTA-P were bismuth oxide, portlandite, dicalcium silicate and tricalcium silicate. The crystal structure of MTA-A were similar to those of MTA-P except for the absence of portlandite. Additionally, MTA-A had tricalcium aluminate differing from MTA-P. BA mainly differed from MTA-P and MTA-A by the radiopacifier (tantalum oxide-TO) in its composition.

Conclusions:

The majority of constituents of the tested materials have shown similarity except for the presence of tricalcium aluminate in MTA-A and the inclusion of TO in BA. In addition, set MTA-P showed a strong peak of portlandite.

Effect of mineral trioxide aggregate surface treatments on morphology and bond strength to composite resin

INTRODUCTION

The aim of this study was to evaluate the micromorphologic changes that accompany different surface treatments on mineral trioxide aggregate (MTA) and their effect on the bond strength to the composite resin with 4 adhesive systems.

METHODS

Three types of MTA cement, ProRoot MTA (WMTA) (Dentsply, Tulsa, OK), MTA Angelus (AMTA) (Angelus, Londrina, PR, Brazil), and Endocem MTA (EMTA) (Maruchi, Wonju, Korea), were prepared and stored for a week to encourage setting. Surface treatment was performed using phosphoric acid or self-etch primer, and an untreated MTA surface was prepared as a control. The surface changes were observed using scanning electron microscopy. MTA surfaces were bonded with 4 adhesive systems, including Scotchbond Multipurpose (3M ESPE, St Paul, MN), Single Bond 2 (3M ESPE), Clearfil SE BOND (Kuraray, Osaka, Japan), and AdheSE One F (Ivoclar Vivadent, Schaan, Liechtenstein), to evaluate the adhesive effectiveness of MTA followed by composite resin restoration. The shear bond strength of the polymerized specimens was tested.

RESULTS

For WMTA and AMTA, untreated surfaces showed an irregular crystalline plate with clusters of globular aggregate particles. For EMTA, the untreated surface presented a reticular matrix with acicular crystals. After surface treatment, superficial crystalline structures were eroded regardless of the MTA cement and adhesive system used. WMTA bonded significantly more strongly than AMTA and EMTA, regardless of the adhesive system used. In the WMTA and AMTA groups, AdheSE One F showed the highest bond strength to the composite. For EMTA, no significant differences were found across adhesive systems.

CONCLUSIONS

Acidic treatment of the MTA surface affected the micromorphology and the bond strength to the composite. Within the limitations of this study, using a 1-step self-etch adhesive system might result in a strong bond to WMTA when the composite resin restoration is required over MTA cement.

Influence of radiopacifying agents on the solubility, pH and antimicrobial activity of portland cement

The aim of this study was to evaluate the interference of the radiopacifiers bismuth oxide (BO), bismuth carbonate (BC), bismuth subnitrate (BS), and zirconiun oxide (ZO) on the solubility, alkalinity and antimicrobial properties of white Portland cement (WPC). The substances were incorporated to PC, at a ratio of 1:4 (v/v) and subjected to a solubility test. To evaluate the pH, the cements were inserted into retrograde cavities prepared in simulated acrylic teeth and immediately immersed in deionized water. The pH of the solution was measured at 3, 24, 72 and 168 h. The antimicrobial activity was evaluated by a radial diffusion method against the microorganisms S. aureus (ATCC 25923), P. aeruginosa (ATCC 27853), E. faecalis (ATCC 29212) and C. albicans (ATCC 10231). The zone of microbial growth inhibition was measured after 24 h. The addition of BS and BC increased the solubility of the cement. The pH values demonstrated that all materials produced alkaline levels. At 3 h, BS showed lower pH than WPC (p<0.05). At 168 h, all materials showed similar pHs (p>0.05). The materials did not present antimicrobial activity for S. aureus, P. aeruginosas and E. faecalis (p>0.05). With regards to C. albicans, all materials formed an inhibition zone, mainly the mixture of WPC with ZO (p<0.05). The type of radiopacifier incorporated into WPC interfered with its physical and antimicrobial properties. ZO was found to be a viable radiopacifier that can be used with WPC.

Present and future of glass-ionomers and calcium-silicate cements as bioactive materials in dentistry: biophotonics-based interfacial analyses in health and disease

Objective

Since their introduction, calcium silicate cements have primarily found use as endodontic sealers, due to long setting times. While similar in chemistry, recent variations such as constituent proportions, purities and manufacturing processes mandate a critical understanding of service behavior differences of the new coronal restorative material variants. Of particular relevance to minimally invasive philosophies is the potential for ion supply, from initial hydration to mature set in dental cements. They may be capable of supporting repair and remineralization of dentin left after decay and cavity preparation, following the concepts of ion exchange from glass ionomers.

Methods

This paper reviews the underlying chemistry and interactions of glass ionomer and calcium silicate cements, with dental tissues, concentrating on dentin–restoration interface reactions. We additionally demonstrate a new optical technique, based around high resolution deep tissue, two-photon fluorescence and lifetime imaging, which allows monitoring of undisturbed cement–dentin interface samples behavior over time.

Results

The local bioactivity of the calcium-silicate based materials has been shown to produce mineralization within the subjacent dentin substrate, extending deep within the tissues. This suggests that the local ion-rich alkaline environment may be more favorable to mineral repair and re-construction, compared with the acidic environs of comparable glass ionomer based materials.

Significance

The advantages of this potential re-mineralization phenomenon for minimally invasive management of carious dentin are self-evident. There is a clear need to improve the bioactivity of restorative dental materials and these calcium silicate cement systems offer exciting possibilities in realizing this goal.

In Vitro Cytotoxicity of White MTA, MTA Fillapex® and Portland Cement on Human Periodontal Ligament Fibroblasts

The aim of this study was to compare the in vitro cytotoxicity of white mineral trioxide aggregate (MTA), MTA Fillapex® and Portland cement (PC) on human cultured periodontal ligament fibroblasts. Periodontal ligament fibroblast culture was established and the cells were used for cytotoxic tests after the fourth passage. Cell density was set at 1.25 X10 4 cells/well in 96-well plates. Endodontic material extracts were prepared by placing sealer/cement specimens (5X3mm) in 1mL of culture medium for 72 h. The extracts were then serially two-fold diluted and inserted into the cell-seeded wells for 24, 48 and 72 h. MTT assay was employed for analysis of cell viability. Cell supernatants were tested for nitric oxide using the Griess reagent system. MTA presented cytotoxic effect in undiluted extracts at 24 and 72 h. MTA Fillapex® presented the highest cytotoxic levels with important cell viability reduction for pure extracts and at ½ and ¼ dilutions. In this study, PC did not induce alterations in fibroblast viability. Nitric oxide was detected in extract-treated cell supernatants and also in the extracts only, suggesting presence of nitrite in the soluble content of the tested materials. In the present study, MTA Fillapex displayed the highest cytotoxic effect on periodontal ligament fibroblasts followed by white MTA and PC.

Subcutaneous connective tissue reactions to various endodontic biomaterials: an animal study

BACKGROUND AND AIMS

Biocompatibility of root-end filling materials is a matter of debate. The aim of this study was to compare the biocompatibility of a variety of commercial ProRoot WMTA cements and a resin-based cement (Geristore®) with different pH values of setting reaction and different aluminum contents, implanted into the subcutaneous connective tissue of rats at various time intervals.

MATERIALS AND METHODS

Fifty Sprague-Dawley rats were used in this study. Polyethylene tubes were filled with Angelus WMTA, ProRoot WMTA, Bioaggregate, and Geristore. Empty control tubes were implanted into subcutaneous tissues and harvested at 7-, 14-, 28- and 60-day intervals. Tissue sections of 5 μm were stained with hematoxylin and eosin and observed under a light microscope. Inflammatory reactions were categorized as 0, none (without inflammatory cells); 1, mild (inflammatory cells ≤25); 2, moderate (25-125 inflammatory cells); and 3, severe (>125 inflammatory cells). Statistical analysis was performed with Kruskal-Wallis and Mann Whitney U tests.

RESULTS

ProRoot WMTA and Angelus elicited significantly less inflammation than other materials (P<0.05). After 7 days, however, all the materials induced significantly more inflammation than the controls (P<0.05). Angelus-MTA group exhi-bited no significant differences from the Bioaggregate group (P=0.15); however, ProRoot WMTA elicited significantly less inflammation than Bioaggregate (P=0.02). Geristore induced significantly more inflammation than other groups (P<0.05).

CONCLUSION

Geristore induced an inflammatory response higher than ProRoot WMTA; therefore, it is not recommended for clinical use.

pH and Antimicrobial Activity of Portland Cement Associated with Different Radiopacifying Agents

Objective. The aim of this study was to evaluate the antimicrobial activity and pH changes induced by Portland cement (PC) alone and in association with radiopacifiers. Methods. The materials tested were pure PC, PC + bismuth oxide, PC + zirconium oxide, PC + calcium tungstate, and zinc oxide and eugenol cement (ZOE). Antimicrobial activity was evaluated by agar diffusion test using the following strains: Micrococcus luteus, Streptococcus mutans, Enterococcus faecalis, Pseudomonas aeruginosa, and Candida albicans. After 24 hours of incubation at 37°C, inhibition of bacterial growth was observed and measured. For pH analysis, material samples (n = 10) were placed in polyethylene tubes and immersed in 10 mL of distilled water. After 12, 24, 48, and 72 hours, the pH of the solutions was determined using a pH meter. Results. All microbial species were inhibited by the cements evaluated. All materials composed of PC with radiopacifying agents promoted pH increase similar to pure Portland cement. ZOE had the lowest pH values throughout all experimental periods. Conclusions. All Portland cement-based materials with the addition of different radiopacifiers (bismuth oxide, calcium tungstate, and zirconium oxide) presented antimicrobial activity and pH similar to pure Portland cement.

Characterization and analyses of acid-extractable and leached trace elements in dental cements

AIMS

Determination of the elemental constitution and investigation of the total and leachable arsenic, chromium and lead in Portland cement, pure tricalcium silicate, Biodentine, Bioaggregate and mineral trioxide aggregate (MTA) Angelus.

METHODOLOGY

The chemical composition of Portland cement, MTA Angelus, tricalcium silicate cement, Biodentine and Bioaggregate was determined using X-ray fluorescence (XRF). Measurements of arsenic, lead and chromium were taken with inductively coupled plasma-mass spectrometry (ICP-MS), following acid digestion on the hydrated material and on leachates of cements soaked in Hank's balanced salt solution (HBSS).

RESULTS

All the cements investigated had a similar oxide composition with the main oxide being calcium and silicon oxide. Both the Portland cement and MTA Angelus had an additional aluminium oxide. The dental cements included a radiopacifying material. All the materials tested had higher acid-extractable arsenic content than the level set by ISO 9917-1 (2007) and an acceptable level of lead. Regardless these high levels of trace elements present in the materials, the leaching in HBSS was minimal for all the dental material tested in contrast to the high levels displayed by Portland cement.

CONCLUSIONS

Dental materials based on tricalcium silicate cement and MTA Angelus release minimal quantities of trace elements when in contact with simulated body fluids. The results of acid extraction could be affected by nonspecific matrix effects by the cement.

Radiopacity evaluation of Portland and MTA-based cements by digital radiographic system

OBJECTIVE

The aim of the present study was to evaluate the radiopacity of Portland and MTA-based cements using the Digora TM digital radiographic system.

MATERIAL AND METHODS

The performed tests followed specification number 57 from the American National Standard Institute/American Dental Association (2000) for endodontic sealing materials. The materials were placed in 5 acrylic plates, especially designed for this experiment, along with a graduated aluminum stepwedge varying from 1 to 10 mm in thickness. The set was radiographed at a 30 cm focus-object distance and with 0.2 s exposure time. After the radiographs were taken, the optical laser readings of radiographs were performed by Digora TM system. Five radiographic density readings were performed for each studied material and for each step of the aluminum scale.

RESULTS

White ProRoot MTA (155.99±8.04), gray ProRoot MTA (155.96±16.30) and MTA BIO (143.13±16.94) presented higher radiopacity values (p<0.05), while white non-structural Portland (119.76±22.34), gray Portland (109.71±4.90) and white structural Portland (99.59±12.88) presented lower radiopacity values (p<0.05).

CONCLUSIONS

It was concluded that MTA-based cements were the only materials presenting radiopacity within the ANSI/ADA specifications.

Nonsurgical approach for strip perforation repair using mineral trioxide aggregate

“Stripping” is lateral perforation is caused by overinstrumentation through a thin wall in the root and is most likely to occur at the inside wall of a curved canal, such as the distal wall of the mesial roots in mandibular first molars. In the past, poor prognosis for strip and furcation perforations was probably due to bacterial leakage or lack of biocompatibility of repair materials. However, the recent development in the techniques and materials such as mineral trioxide aggregate (MTA) has enhanced the prognosis for such cases. There is limited literature on use of MTA as an obturating material in the treatment of strip perforation. This study presents two cases of strip perforation that are successfully repaired nonsurgically using MTA with 2-year follow up. Cases suggest that MTA can be used as an alternative root canal obturation material for the treatment of strip perforation. The property differences between gray and white MTA are reviewed.

The chemical composition of mineral trioxide aggregate

Mineral trioxide aggregate (MTA) is composed of Portland cement, with 4:1 addition of bismuth oxide added so that the material can be detected on a radiograph. The cement is made up of calcium, silicon and aluminium. The main constituent phases are tricalcium and dicalcium silicate and tricalcium aluminate. There are two commercial forms of MTA, namely the grey and the white. The difference between the grey and the white materials is the presence of iron in the grey material, which makes up the phase tetracalcium alumino-ferrite. This phase is absent in white MTA. Hydration of MTA occurs in two stages. The initial reaction between tricalcium aluminate and water in the presence of calcium sulphate results in the production of ettringite. Tricalcium and dicalcium silicate react with water to produce calcium silicate hydrate and calcium hydroxide, which is leached out of the cement with time.

CO(2), Er: YAG and Nd:YAG lasers in endodontic surgery

Objectives:

CO₂, Er:YAG and Nd:YAG lasers have been used in endodontic surgery. This in vitro study evaluated 1% Rhodamine B dye penetration using computer-assisted morphometry (ImageTool Software®) of 108 endodontically treated human permanent canines.

Material and methods:

Teeth were divided into 9 groups according to the technique used: A: 90-degree apicoectomy with bur, root-end cavity preparation with ultrasound and filled with MTA; B: 90-degree apicoectomy with bur, root-end cavity prepared with ultrasound and filled with MTA, and treatment of apical surface with CO₂ laser (1 W, CW/CW); C: 90-degree apicoectomy with bur, and treatment of apical surface with Nd:YAG laser (150 mJ, 10 Hz); D: 90-degree apicoectomy with bur, and treatment of apical surface with CO₂ laser (1 W, CW/CW); E: apicoectomy with Er:YAG laser (400 mJ, 10 Hz), root-end cavity prepared with ultrasound and filled with MTA; F: apicoectomy with Er:YAG laser (400 mJ, 10 Hz) and treatment of apical surface with Nd:YAG laser (150 mJ, 10Hz); G: apicoectomy with CO₂ laser (5W, CW/SP), root-end cavity prepared with ultrasound and filled with MTA; H: irradiation of apical end with CO₂ laser (1 W, CW/CW); I: irradiation of apical end with Nd:YAG laser (150 mJ, 10 Hz).

Results:

Dye penetration was found in all specimens at different rates, the lowest penetration occurring in groups C (16.20%), B (17.24%) and F (17.84%).

Conclusions:

Groups B, C and F represent the best technical sequences to perform endodontic surgery.

Cytotoxic effects of White-MTA and MTA-Bio cements on odontoblast-like cells (MDPC-23)

This study evaluated the cytotoxic effects of 2 mineral trioxide aggregate (MTA) cements - White-MTA-Angelus and a new formulation, MTA-Bio - on odontoblast-like cell (MDPC-23) cultures. Twenty-four disc-shaped (2 mm diameter x 2 mm thick) specimens were fabricated from each material and immersed individually in wells containing 1 mL of DMEM culture medium for either 24 h or 7 days to obtain extracts, giving rise to 4 groups of 12 specimens each: G1 - White-MTA/24 h; G2 - White-MTA/7 days; G3 - MTA-Bio/24 h; and G4 - MTA-Bio/7 days. Plain culture medium (DMEM) was used as a negative control (G5). Cells at 30,000 cells/cm² concentration were seeded in the wells of 24-well plates and incubated in a humidified incubator with 5% CO2 and 95% air at 37ºC for 72 h. After this period, the culture medium of each well was replaced by 1 mL of extract (or plain DMEM in the control group) and the cells were incubated for additional 2 h. Cell metabolism was evaluated by the MTT assay and the data were analyzed statistically by ANOVA and Tukey's test (α=0.05). Cell morphology and the surface of representative MTA specimens of each group were examined by scanning electron microscopy. There was no statistically significant difference (p>0.05) between G1 and G2 or between G3 and G4. No significant difference (p>0.05) was found between the experimental and control groups either. Similar cell organization and morphology were observed in all groups, regardless of the storage periods. However, the number of cells observed in the experimental groups decreased compared to the control group. MTA-Bio presented irregular surface with more porosities than White-MTA. In conclusion, White-MTA and MTA-Bio presented low cytotoxic effects on odontoblast-like cell (MDPC-23) cultures.

L929 cell response to root perforation repair cements: an in vitro cytotoxicity assay

This study compared the cytotoxicity of an experimental epoxy-resin and calcium hydroxide-based cement (MBPc), gray mineral trioxide aggregate (MTA) and white mineral trioxide aggregate (WMTA) using the agar overlay method with neutral red dye. L929 cells were seeded into 6-well culture plates where 48-h set test materials were placed on the agar overlay, in triplicate. Teflon and natural rubber served as negative and positive controls. After an incubation period of 24 h at 37 degrees C in a humidified atmosphere of 5% CO2 in air, a discolored area around the samples and the positive controls could be observed and measured per quadrant. The mean values were compared and converted into grades to classify the results according to the table of cytotoxicity grades according to the Standard Operating Procedures (SOP) of the Oswaldo Cruz Foundation, Brazil. The nonviable cell areas and the morphological changes in the cells were observed with an inverted microscope. The results showed grade 1 (slight) for the two types of MTA (p>0.05) and grade 2 (mild) for the MBPc (p<0.001). All samples met the requirements of the test as none of the cultures showed reactivity higher than grade 2.