Evaluating antimicrobial activity and cytotoxicity of silver nanoparticles incorporated into reinforced zinc oxide eugenol: an in vitro study.

PURPOSE: This study aimed to evaluate the antibacterial and cytotoxic effects of reinforced zinc oxide-eugenol (rZOE) incorporated with different concentrations of silver nanoparticles (AgNPs). METHODS: The pastes of rZOE alone or mixed with AgNPs at concentrations of 1%, 2%, and 5% of weight were prepared. In vitro antimicrobial activity of prepared materials against Streptococcus (S.) mutans and Lactobacillus (L.) acidophilus were evaluated after 2, 4, and 6 h of contact times using direct contact test (DCT) and also following 24 h incubation by well-diffusion test (WDT). The cytotoxicity of the tested materials on human dental pulp stem cells was also determined by MTT assay. RESULTS: The DCT demonstrated that the time-dependent reductions of the colony numbers of both bacteria by three different concentrations of AgNPs incorporated into rZOE were equal but steeper than the rZOE alone (P < 0.05). The increases in growth inhibition zones of S. mutans and L. acidophilus were associated with the increasing concentration of AgNPs mixed with rZOE in the WDT; however, statistical analysis did not show any significant differences (P = 0.092). The MTT assay revealed a significantly lower percentage of cell viability after 1 day of culture only with the rZOE + AgNP5% in comparison to the rZOE alone (P = 0.011) and the control medium (P = 0.001). CONCLUSION: Since the antimicrobial activities of three different concentrations of AgNPs incorporated into rZOE were equal and AgNPs had lower toxicity at lower concentrations, using AgNPs at 1% concentration is suggested to be mixed with rZOE.

Cytotoxicity of Different Concentrations of Three Root Canal Sealers on Human Mesenchymal Stem Cells.

This study assessed the dose-dependent effect on the cytotoxicity of BioRoot RCS (BR) and Endosequence BC (BC) sealers in human bone marrow mesenchymal stem cells (hMSCs) compared to those of the AH Plus sealer. Cells were exposed to different dilutions of extracts from freshly prepared sealers (1:2, 1:8, 1:32). Unexposed cells acted as the negative control. Cytotoxicity was evaluated by an alamar blue assay. Cell morphology was analyzed by using scanning electron microscopy after exposure to the different sealers' extracts. Statistical analysis was performed using a one-way analysis of variance and the Bonferroni post hoc test (p < 0.05). The cytotoxicities of BC and BR were less than that of AH Plus. In the presence of 1:2 BR, the cell proliferation was significantly lower than the control. At 1:8 and 1:32 concentrations, both the tricalcium silicate sealers led to similar cellular proliferation. Cells in BC and BR sealers' extracts spread better than those in AH Plus extract.

Comparative Evaluation of Cytotoxicity of Root Canal Sealers on Cultured Human Periodontal Fibroblasts: In vitro Study.

AIM: To evaluate and compare the cytotoxic effects of different types of root canal. MATERIALS AND METHODS: The sealers were eluted with culture medium for 1 hour, 7 days, and 14 days. Cell viability was estimated by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay and trypan blue exclusion method on human periodontal ligament (PDL) fibroblast cells. Sealers used are mineral trioxide aggregate (MTA)-based sealer (MTA Fillapex, Angelus), calcium hydroxide-based sealer (Apexit Plus, Ivoclar Vivadent), resin-based sealer (AH Plus, Dentsply), and zinc oxide eugenol-based sealer (Tubli Seal, SybronEndo). RESULTS: The order of cytotoxicity through MTT assay, at the end of the second week, was observed as MTA Fillapex> Tubli Seal> Apexit Plus > AH Plus. The percentage cell viability obtained after trypan blue exclusion method decreased in the order of Apexit Plus> Tubli Seal> AH Plus> MTA Fillapex, which was similar to the reported cytotoxicity from the MTT assay after 1 hour. CONCLUSION: Each type of sealer showed moderate-to-severe cytotoxic response when compared with the control. The MTA Fillapex was found to be the most cytotoxic sealer. Use of resin-based material as a root canal sealer may result in a more favorable response to PDL fibroblasts. CLINICAL SIGNIFICANCE: Having knowledge of the cytotoxicity of various sealers will help in increasing patient's comfort.

Cytotoxicity and bioactivity of various pulpotomy materials on stem cells from human exfoliated primary teeth.

AIMS: To investigate the cytotoxicity and bioactivity of several pulpotomy materials: Biodentine (Septodont, Saint-Maur-des-Fosses, France) MTA (Angelus, Londrina, PR, Brazil), Theracal LC (Bisco Inc., Schamburg, IL, USA) and IRM (Dentsply DeTrey GmbH, Konstanz, Germany), after contact with stem cells isolated from human exfoliated primary teeth (SHEDs). METHODOLOGY: SHEDs were cultured in the presence of the eluates of various pulpotomy materials for 24, 48 and 72 h. Cell viability was determined by mitochondrial dehydrogenase enzymatic (MTT) assay. Apoptosis and changes in cell phenotype were evaluated by flow cytometry. Also, an in vitro scratch wound-healing assay was used to determine their effects on cell migration. To assess cell morphology and attachment to the different pulpotomy materials, SHEDs were directly seeded onto the material surfaces and analysed by scanning electron microscopy (SEM). Finally, the deposition of a calcified matrix in presence of these materials was verified by Alizarin Red staining. Statistical analysis was performed with analysis of variance and Bonferroni or Tukey post-test (α = 0.05). RESULTS: Cell viability in the presence of Biodentine eluates was significantly higher to that obtained using complete medium alone (control; P < 0.01) and was also significantly higher than using MTA Angelus from 48 h of incubation (P < 0.01). However, Theracal LC and IRM were associated with low rates of cell viability (P < 0.001). Similar results were obtained in an apoptosis assay. In addition, SHEDs maintained their mesenchymal phenotype in all conditions although their capacity to migrate was higher in the presence of Biodentine. SEM studies revealed a suitable proliferation rate, cell spreading and attachment, especially when using Biodentine and MTA Angelus discs. Finally, Biodentine eluates significantly induced calcified matrix deposition from 7 days of culture (P < 0.01). CONCLUSIONS: Biodentine exhibited better cytocompatibility and bioactivity than MTA Angelus, Theracal LC and IRM.

A Comparative Evaluation of the Effect of the Addition of Pachymic Acid on the Cytotoxicity of 4 Different Root Canal Sealers-An In Vitro Study.

INTRODUCTION: Root canal sealers exhibit varying degrees of cytotoxicity to periapical tissues. This in turn results in inflammation, delayed wound healing, and even bone resorption. This study aimed to explore the effect of the addition of an antioxidant like pachymic acid on the cytotoxicity of 4 root canal sealers, namely, Tubliseal (Kerr, Romulus, MI), a zinc oxide eugenol-based sealer; AH Plus (Dentsply De Trey GmbH, Konstanz, Germany), an epoxy resin-based sealer; Sealapex (Kerr), a calcium hydroxide-based sealer; and EndoREZ (Ultradent Products, South Jordan, UT), a methacrylate resin-based sealer. METHODS: Sealers mixed according to the manufacturers' instructions formed the experimental groups. Subgroups were determined based on the absence (subgroup A) or addition (subgroup B) of pachymic acid. The experimental sealers were added to L929 mouse fibroblast cells immediately after mixing. Cell viability was evaluated by methylthiazoletetrazolium assay after 24 hours. Data were analyzed using 1-way analysis of variance. Intergroup comparisons were performed using the Kruskal-Wallis test, and intragroup comparisons were done using independent t and post hoc tests. RESULTS: All 4 sealers were cytotoxic but to varying degrees. In both the subgroups, Sealapex exhibited the lowest cytotoxicity followed by AH Plus, Tubliseal, and EndoREZ (P < .05). The addition of pachymic acid reduced the cytotoxicity of all the sealers except that of EndoREZ (P > .05). CONCLUSIONS: Calcium hydroxide-based Sealapex showed the least cytotoxicity compared with the other sealers. Pachymic acid could be a viable therapeutic agent to overcome the potential adverse effects associated with root canal sealers.

[Effect of root canal sealers on biocompatibility of human periodontal ligament cells].

OBJECTIVE: To compare the effects of three root canal sealers with respect to time on biocompatibility of human periodontal ligament cells (hPDLCs).The sealers included zinc oxide and eugenol based sealers (ZOE), epoxy resin sealers (ERS) and silicone based sealers (SBS). METHODS: hPDLCs were primarily cultured,with the method combining of tissue explant and enzymatic digestion. The cells were then exposed to different extract fluids: (1) ZOE extracted for 24 h group ;(2) ZOE extracted for 1 week group;(3)ZOE extracted for 2 weeks group;(4) ERS extracted after 24 h group; (5) ERS extracted after 1 week group; (6) ERS extracted after 2 weeks group; (7) SBS extracted after 24 h group; (8) SBS extracted after 1 week group; (9) SBS extracted after 2 weeks group; (10) Dulbecco modified Eagle's medium/F12 (DMEM/F12) as negative control group. Cell morphology was observed under an inverted microscope.Cell proliferation was measured by methyl-thiazol-diphenyltetrazolium (MTT) assay. ALP assay kit was used for measuring alkaline phosphatase (ALP) activity. Sealers of 2 weeks' setting time were then immersed in an osteogenic medium for examination of mineral nodules and calcium deposits. RESULTS: Considering the relative growth rate(RGR),ZOE was severely to moderately cytotoxic(RGR:13.6%-39.9%), while ERS was slightly or not cytotoxic (RGR: 87.6%-95.3%).Only SBS did not show any cytotoxicity after setting (RGR: 91.8%-106.7%). The setting time influenced the cytotoxicity of ERS which decreased after 1 week. Considering the ALP activity,there was no difference between SBS group and control group (F=3.397,P=0.053). According to the results of calcium deposits, ZOE:D562 nm=0.180±0.050,ERS: D562 nm=2.968±0.201,SBS:D562 nm=3.623±0.039,Control:D562 nm=3.477±0.102,the ranking of ALP activity and calcium deposits was as follows: ZOE

Cytotoxicity and osteogenic potential of silicate calcium cements as potential protective materials for pulpal revascularization.

OBJECTIVES: In pulpal revascularization, a protective material is placed coronal to the blood clot to prevent recontamination and to facilitate osteogenic differentiation of mesenchymal stem cells to produce new dental tissues. Although mineral trioxide aggregate (MTA) has been the material of choice for clot protection, it is easily displaced into the clot during condensation. The present study evaluated the effects of recently introduced calcium silicate cements (Biodentine and TheraCal LC) on the viability and osteogenic differentiation of human dental pulp stem cells (hDPSCs) by comparing with MTA Angelus. METHODS: Cell viability was assessed using XTT assay and flow cytometry. The osteogenic potential of hDPSCs exposed to calcium silicate cements was examined using qRT-PCR for osteogenic gene expressions, alkaline phosphatase enzyme activity, Alizarin red S staining and transmission electron microscopy of extracellular calcium deposits. Parametric statistical methods were employed for analyses of significant difference among groups, with α=0.05. RESULTS: The cytotoxic effects of Biodentine and TheraCal LC on hDPSCs were time- and concentration-dependent. Osteogenic differentiation of hDPSCs was enhanced after exposure to Biodentine that was depleted of its cytotoxic components. This effect was less readily observed in hDPSCs exposed to TheraCal LC, although both cements supported extracellular mineralization better than the positive control (zinc oxide-eugenol-based cement). SIGNIFICANCE: A favorable tissue response is anticipated to occur with the use of Biodentine as a blood clot-protecting material for pulpal revascularization. Further investigations with the use of in vivo animal models are required to validate the potential adverse biological effects of TheraCal LC on hDPSCs.

Assessment of cytotoxic potential of root canal sealers after hardening - an ex vivo study.

AIM: The aim of this study was to perform a comparative assessment of the toxic action of root canal sealers currently on the market on human gingival fibroblasts after setting. MATERIAL/METHODS: The inserts with an equal quantity of set root canal sealers were transferred into 24-well culture dishes containing human gingival fibroblasts cultured in Dulbecco's Modified Eagle's Medium (DMEM) supplemented with 10% fetal calf serum (FCS). The dishes with materials were incubated at 37°C, 100% humidity and in an atmosphere of 5% CO2 for 24 h. The cytotoxic effects of the root canal materials were measured by the mitochondrial succinate dehydrogenase activity in living cells using tetrazolium bromide (MTT assay). RESULTS: Epiphany and Sealapex exhibited high toxicity towards human gingival fibroblasts - 25.57% ± 0.88 and 27.63 % ± 2.35 respectively (less than 30% live cells in the culture). The remaining materials were characterized by lack of a cytotoxic effect (over 90% of live cells in the culture). None of the preparations exhibited moderate or low toxicity. CONCLUSIONS: The majority of root canal sealers tested after hardening were well tolerated by human gingival fibroblasts. Only two materials were characterized by high toxicity: with methacrylate (Epiphany) and calcium hydroxide (Sealapex).

In vitro biocompatibility and oxidative stress profiles of different hydraulic calcium silicate cements.

INTRODUCTION: MTA Plus is a new calcium silicate cement with unknown cytotoxicity characteristics. The objectives of this study were to examine the effect of MTA Plus on the viability, apoptosis/necrosis profile, and oxidative stress levels of rat odontoblast-like cells. METHODS: MDPC-23 cells were exposed to gray and white MTA Plus (GMTAP, WMTAP), gray and white ProRoot MTA (GMTA, WMTA) cements, or their eluents. The cells were evaluated for (1) cell viability by using XTT assay, (2) apoptosis/necrosis by using flow cytometry and confocal laser scanning microscopy, and (3) oxidative stress by measuring reactive oxygen species. RESULTS: XTT assay showed that all test cements exhibited marked initial cytotoxicity that decreased with time. By the end of the third week, GMTAP and GMTA were comparable to untreated cells (negative control) in terms of cell viability, whereas WMTAP and WMTA were significantly lower than the untreated cells. Apoptosis/necrosis profiles of cells exposed to WMTAP and GMTAP were not significantly different from untreated cells, whereas cells exposed to WMTA and GMTA showed significantly less viable cells. All experimental groups exhibited reduction of intracellular reactive oxygen species formation compared with untreated cells, although cells exposed to WMTA were not significantly different from untreated cells. CONCLUSIONS: Both the gray and white versions of MTA Plus possess negligible in vitro cytotoxic risks that are time and dilution dependent. They enrich the spectrum of hydraulic calcium silicate cements currently available to clinicians for endodontic applications.

Effects of ProRoot MTA, Bioaggregate, and Micromega MTA on odontoblastic differentiation in human dental pulp cells.

INTRODUCTION: The aim of this study was to compare the biocompatibility and odontogenic potential of newly developed Bioaggregate (BA) and Micromega MTA (MMTA) with ProRoot MTA (PMTA) and intermediate restorative material (IRM) by using human dental pulp cells. METHODS: Biocompatibility was assessed by an 3-(4,5-dimethylthiazolyl-2-yl)-2,5-diphenyltetrazolium bromide assay and scanning electron microscopy. Differentiation was evaluated by alkaline phosphatase (ALP) activity, alizarin red staining, and reverse transcriptase-polymerase chain reaction for the maker genes. The levels of inflammatory mediators and cytokines were measured by reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assay. RESULTS: PMTA, BA, and MMTA exhibited equally good biocompatibility, whereas IRM showed cytotoxicity compared with these materials. PMTA, BA, and MMTA increased the ALP activity, promoted mineralization nodule formation, and enhanced the mRNA expression level of the osteogenic/odontogenic markers (ALP, osteopontin, osteocalcin, dentin sialophosphoprotein, and dentin matrix protein-1) compared with IRM. The levels of proinflammatory mediators and proinflammatory cytokines were lower in PMTA, BA, and MMTA compared with the IRM group. CONCLUSIONS: Collectively, the biocompatibility, odontogenic potentials, and inflammatory response of BA and MMTA are equal to those of PMTA and superior to those of IRM.

Rat subcutaneous tissue response to MTA Fillapex® and Portland cement.

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

Evaluation of the biocompatibility of resin-based root canal sealers in rat periapical tissue.

We evaluated the biocompatibility of resin-based root canal sealers (RCSs) in the periapical tissues of rats. Wistar rats underwent tooth replantation for reproducing the response of periapical tissue with RCSs. The resin-based Epipany SE, AH Plus Jet, the eugenol-based sealer (Canals) and a control group were employed. The upper right first molar was extracted and applied with RCSs on apices, and then the tooth was repositioned. Histological evaluation demonstrated that mild inflammation occurred in the periapical tissue with Epiphany and AH Plus Jet sealers on day 7, whereas Canals induced severe-to-moderate inflammation. The statistical analyses demonstrated that the significant differences were observed between Canals and the other groups on day 7 regarding inflammatory response. On day 14, the lesions induced by all sealers were healed and replaced predominantly by fibrous connective tissue. Our results suggest that Epiphany SE and AH Plus Jet are good biocompatible materials.

Cytotoxicity and proliferative effects of Iodoform-containing root canal-filling material on RAW 264.7 macrophage and RKO epithelial cell lines.

OBJECTIVE: The present study investigated the effect of the Iodoform-containing root canal filling material on the viability of cultured macrophages and epithelial cells, and on cytokine secretion. DESIGN: The effect of Endoflas F.S. on the proliferation of a RAW 264.7 macrophage cell line and on a RKO epithelial cell line, and on the production of tumour necrosis factor alpha (TNFα) from macrophages was examined. Cell vitality was evaluated using a colourimetric XTT (sodium 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)-carbonyl]-2H-tetrazolium inner salt) assay. The presence of cytokines was determined by two-site enzyme-linked immunosorbent assay (ELISA). RESULTS: Direct exposure of Endoflas F.S. and its media, up to a dilution of 1/8, decreased the viability of macrophages and epithelial cells by ∼70% compared to control media (P<0.05). Media dilution from 1/16 to 1/1024 demonstrated a proliferative effect, increasing cell viability by about 60% compared to media without Iodoform-containing root canal filling material. CONCLUSIONS: Direct and indirect exposure to high concentrations of iodoform-containing root canal filling material showed a cytotoxic effect on macrophages and epithelial cells, while low concentrations induced cell proliferation.

Rat subcutaneous tissue response to MTA Fillapex® and Portland cement

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

O objetivo deste estudo foi avaliar a resposta do tecido subcutâneo de rato ao MTA Fillapex® (Angelus), a um cimento endodôntico experimental à base de cimento Portland e propilenoglicol, e à pasta de óxido de zinco e eugenol com iodofórmio. Estes materiais foram colocados em tubos de polietileno e implantados no tecido conjuntivo do dorso de ratos Wistar, por 7 e 15 dias. Os espécimes foram corados com hematoxilina e eosina e os parâmetros de reação inflamatória foram avaliados em microscópio óptico. A intensidade da resposta inflamatória provocada pelos cimentos foi analisada em todos os períodos por dois observadores previamente calibrados (kappa 0,96) e sem conhecimento dos grupos experimentais. O exame histológico mostrou que todos os materiais provocaram reação inflamatória moderada aos 7 dias que regrediu com o tempo. A maior resposta inflamatória do tecido foi observada aos 7 dias, nos tubos preenchidos com pasta de Óxido de Zinco e Eugenol com Iodofórmio. Os tubos com MTA Fillapex apresentaram algumas células gigantes, macrófagos e linfócitos após 7 dias. Aos 15 dias, a presença de fibroblastos e fibras de colágenas foi observada, indicando processo de cicatrização do tecido. Os tubos com o cimento Portland mostraram resultados semelhantes aos observados no grupo MTA Fillapex. Aos 15 dias, a reação inflamatória apresentada foi praticamente ausente, com muitas fibras colágenas, indicando cicatrização normal do tecido. A análise estatística mostrou diferença estatisticamente significante entre o grupo de cimento Portland (15 dias) e óxido de zinco eugenol com Iodofórmio (7 dias) (p<0,05). Nos outros grupos não houve diferença estatística significante. MTA Fillapex e cimento Portland são mais biocompatíveis do que os outros cimentos testados.

Evaluation of the cytotoxicity of different root canal sealers on L929 cell line by MTT assay.

The purpose of this study was to evaluate the cytotoxic effects of commercially available root canal sealers [Sealite Ultra (SU), Tubli-Seal (TS), Tubli-Seal EWT (TS-EWT), Pulp Canal Sealer (PCS), Pulp Canal Sealer EWT (PCS-EWT), Endomethasone N (En N), and Apexit Plus (AP)] on L929 cells by using MTT assay. After incubation with each sealer's extract at 37°C in a humidified air atmosphere containing 5% CO(2 )for 24 h, MTT (5 mg/mL) in saline was added into each well and further incubated at 37°C for 4 h. Formazan precipitate was dissolved in a buffer containing 23% sodium dodecyl sulfate and 50% N, N-dimethylformamide (pH 4.7). Optical densities of dissolved formazan were read using a microplate spectrophotometer. AP, TS, and TS-EWT showed no cytotoxicity at any dilution tested. Other sealers exhibited some degree of cytotoxicity at the 1/4 and 1/2 dilutions. PCS-EWT and SU exerted more potent cytotoxicity at 1/2 dilution than the other sealers.

Cytotoxicity of newly developed ortho MTA root-end filling materials.

INTRODUCTION: Various materials have been advocated for use as root-end filling materials. The purpose of the present in vitro study was to compare the cytotoxicity of 4 root-end filling materials: glass ionomer cement (GIC; Fuji II, GC Corp, Tokyo, Japan), reinforced zinc oxide-eugenol cement (IRM; Dentsply Tulsa Dental, Tulsa, OK), and 2 types of mineral trioxide aggregate. METHODS: This study used MG-63 cells derived from a human osteosarcoma. To quantitatively evaluate the cytotoxicity of test materials, the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay was used. The cells were exposed to the extracts and incubated. Cell viability was recorded by measuring the optical density of each test well in reference to controls. Each specimen was examined by scanning electron microscopy for the observation of cell morphology. RESULTS: The XTT assay showed that the cell viability of ProRoot MTA (Dentsply Tulsa Dental) was higher than that of GIC and Ortho MTA (BioMTA, Seoul, Republic of Korea) at all time points. IRM showed significantly lower cell viability than the other groups. The scanning electron microscopic analysis revealed that elongated, dense, and almost confluent cells were observed in the cultures of GIC, Ortho MTA, and ProRoot MTA specimens. In contrast, cells on the surface of IRM were rounded in shape, and the numbers and the density of the cells were smaller than that in the other groups. CONCLUSIONS: ProRoot MTA and GIC showed good biocompatibility in this study. However, Ortho MTA showed lower biocompatibility compared with ProRoot MTA and GIC.

Reaction of rat subcutaneous connective tissue to a mineral trioxide aggregate-based and a zinc oxide and eugenol sealer.

INTRODUCTION: The purpose of this study was to evaluate the subcutaneous connective tissue reaction in rats to a mineral trioxide aggregate (MTA)-based endodontic sealer Fillapex (Angelus, Londrina, PR, Brazil) and compare it with Grossman sealer (Farmadental, Buenos Aires, Argentina). METHODS: Sterile medical-grade silicone tubes containing the test materials were implanted in 24 Wistar rats. After 10, 30, and 90 days, the animals (n = 8 per period) were euthanized, and the implants along with their surrounding tissues were dissected, fixed, and processed for histologic evaluation. A 4-category evaluation system was used to evaluate the microscopic observations. The tissue response on the lateral walls of the silicone tubes was used as the negative control. The data were analyzed for statistical significance using the Wilcoxon signed rank, Kruskal-Wallis, and Dunn tests. RESULTS: Fillapex showed a severe tissue reaction for all 3 observation periods. Grossman sealer showed similar features after 10 and 30 days, but the reaction decreased slightly after 90 days. In contrast, the negative controls did not show adverse reactions in any sample of the 3 time periods. After 10 and 30 days, no statistically significant differences were found between Fillapex and Grossman sealer (P > .05); however, the difference was significant after 90 days (P < .05). For all experimental periods, there were statistically significant differences between both Fillapex and Grossman sealer and the negative controls (P < .05). CONCLUSIONS: It was concluded that both MTA-Fillapex and Grossman sealer remained toxic to subcutaneous tissues in rats after 90 days.

Cytocompatibility of the ready-to-use bioceramic putty repair cement iRoot BP Plus with primary human osteoblasts.

AIM: To verify the in vitro cytocompatibility of iRoot BP Plus (iRoot) and to compare it with White ProRoot MTA (MTA). METHODOLOGY: Thirty-six human maxillary incisor root canals were prepared using a step-back flaring technique. The apical 3 mm was resected perpendicular to the long axis at the roots, and root-end cavities were prepared with the aid of an ultrasonic device plus a diamond retrotip with continuous irrigation using water, producing standardized preparations. After that, the root-end cavities were filled with iRoot or MTA, and each root was exposed to cell culture media for 24 or 48 h. Human osteoblast cells were exposed to the extracts thus obtained, and a multiparametric cell viability assay was performed, evaluating mitochondrial activity, membrane integrity and cell density. The results were analysed by one-way analysis of variance, complemented with the Duncan post-test (P < 0.05). RESULTS: Cells exposed to MTA revealed a cytocompatibility pattern similar to the untreated cells (negative control), at both experimental times (P > 0.05). iRoot, however, promoted a significantly poorer viability than MTA and the control, after 48 h of exposure (P < 0.001). Nevertheless, iRoot did not induce critical cytotoxic effects because cell viability remained higher than 70% of the control group in most tests performed. CONCLUSION: iRoot and MTA were biocompatible and did not induce critical cytotoxic effects.

A multiparametric assay to compare the cytotoxicity of endodontic sealers with primary human osteoblasts.

AIM: To compare the cytotoxicity of four endodontic sealers (Sealapex, Pulp Canal Sealer EWT, Real Seal and MTA Fillapex) either 1 or 7 days after mixing, when assessed through a multiparametric analysis employing human primary cells closely related to periapical tissues. METHODOLOGY: Extracts of each sealer were prepared following 24-h exposure to culture media, at either 24 h or 7 days after mixing. Primary human osteoblasts were exposed to extracts for 24 h, at 37 °C with 5% CO(2) , and cell viability was evaluated by a multiparametric assay assessing sequentially, on the same cells, mitochondrial activity (XTT), membrane integrity (neutral red test) and total cell density (crystal violet dye exclusion test). Results from each test and experimental time were compared by 2-way analysis of variance (anova). RESULTS: All endodontic sealers had strong cytotoxicity 24 h after mixing, according to all parameters evaluated. At a longer setting period (7 days), viability for Sealapex was significantly increased (P < 0.05) and Pulp Canal Sealer achieved levels of cytocompatibility similar to the control group. The anova indicated a general correlation between the cytotoxicity of the materials and the time after mixing, with some level of dependence on the cell viability assay employed. CONCLUSIONS: All materials had high cytotoxic levels for human primary cells, mostly on a time-dependent basis, as shown by three different cell viability tests.

Cytotoxicity evaluation of Gutta Flow and Endo Sequence BC sealers.

OBJECTIVE: This study evaluated the cytotoxicity of GuttaFlow and EndoSequence BC sealers and compared them with AH Plus and Tubli-Seal sealers. STUDY DESIGN: Samples (0.5 mg) of freshly mixed or set BC, GuttaFlow, AH Plus, and Tubli-Seal sealers were eluted with 300, 600, and 1,000 µL cell culture medium for 24 and 72 hours. L929 cells were seeded into 96-well plates at 3 × 10(4) cells/well and cultured with 100 µL eluate from each eluate group. Cells cultured only with culture medium served as control. After 24 hours' incubation, the cytotoxicity was evaluated by MTT assay. Cell viability was calculated as the percentage of the control group, and the results were analyzed with a one-way analysis of variance. RESULTS: For the freshly mixed sealer, cell viability in the AH Plus group was less than in all of the other 3 sealer groups. The Tubli-Seal sealer group had less cell viability than the EndoSequence BC and GuttaFlow sealer groups. For the set sealer, the Tubli-Seal and AH Plus groups had less cell viability than the EndoSequence BC and GuttaFlow sealer groups. There was no cell viability difference between the EndoSequence BC and GuttaFlow sealer groups in the either freshly mixed or set sealer group. CONCLUSIONS: The GuttaFlow and EndoSequence BC sealers have lower cytotoxicity than the AH Plus and Tubli-Seal sealers.