In Vitro Cytotoxicity Evaluation of a Self-adhesive, Methacrylate Resin–based Root Canal Sealer

Cytotoxicity and Genotoxicity of Epoxy Resin-Based Root Canal Sealers before and after Setting Procedures

Epoxy resin-based sealers are commonly used for successful endodontic treatment. This study aimed to evaluate the cytotoxicity and genotoxicity of epoxy resin-based sealers under unset and set conditions. Three epoxy resin-based sealers were used: Adseal, AH Plus, and Dia-Proseal. To test cytotoxicity, an agar overlay test and a 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay were performed using unset and set sealers on L929 mouse fibroblasts. The genotoxicity test of the comet assay was performed using the same cell line. Extract dilutions in the culture media were used as test materials for the MTT and comet assays. The comet tail produced by the damaged DNA was calculated by image analyses. Statistical analyses were performed using one-way analysis of variance and Tukey’s post hoc test. Unset sealers did not show defined decolorized areas. Hardened specimens of resin-based sealers showed circular discolored zones in the agar overlay test. Dia-Proseal was the least cytotoxic after hardening. These results were confirmed in the MTT assay. Cell viability was significantly higher in cells treated with hardened sealers in both groups than that in cells treated with freshly mixed sealers in the MTT assay. Unset AH Plus^® and Dia-Proseal™ significantly increased cell viability with decreasing dilution. Adseal™ was the least cytotoxic. Freshly mixed Adseal™ was more genotoxic when freshly mixed than when set. Unset epoxy resin-based sealers were generally more cytotoxic and genotoxic than set materials. Cytotoxicity does not always match the genotoxicity results; therefore, various test tools are required to test toxicity. It is necessary to properly evaluate the toxic effects to establish a biocompatibility test that mimics clinical conditions.

Influence of Commonly Used Endodontic Irrigants on the Setting Time and Metal Composition of Various Base Endodontic Sealers

The present study aimed to evaluate if commonly used endodontic irrigants such as 3% sodium hypochlorite (NaOCl, Prime Dental, Thane, India), 2% chlorhexidine (CHX, Sigma-Aldrich Co., St. Louis, MO, USA), and 17% ethylenediaminetetraacetic acid (EDTA, Meta-Biomed Co. Ltd., Cheongju-si, South Korea) influenced the setting time and metal composition of different base endodontic sealers on exposure. AH Plus (Dentsply De Trey GmbH, Konstanz, Germany), Sealapex (SybronEndo, Orange, CA, USA), mineral trioxide aggregate (MTA) Fillapex (Angelus Soluções Odontológicas, Londrina, Brazil), and Tubli-Seal (Kerr Dental, Orange, CA, USA) were selected as the different base representatives of endodontic sealers. These sealers were exposed to 3% NaOCl, 2% CHX, and 17% EDTA, and the individual setting time of the sealers was analyzed. The samples were analyzed for heavy metal elements such as chromium (Cr), nickel (Ni), cobalt (Co), cadmium (Cd), arsenic (As), mercury (Hg), lead (Pb), and beryllium (Be) by using inductively coupled plasma mass spectrometry (ICP-MS) analysis. For statistical analysis, one-way ANOVA and post hoc Tukey’s tests were used. All selected sealers showed variation in setting time post-exposure to different irrigants. MTA Fillapex had the shortest mean setting time (215.7 min, post-exposure at 187.3 min) (p < 0.05). Mean setting time was also affected for AH Plus (479.6 min, post-exposure at 423.9 min) (p < 0.05) and Tubli-Seal (514.7 min, post-exposure at 465.2 min) (p < 0.05). Sealapex showed the maximum reduction of setting time (864.8 min, post-exposure at 673.4 min) (p < 0.05). All tested sealers showed heavy metals (Cr, Ni, Co, Cd, As, Hg, and Pb) in their composition, and the quantities were influenced by interaction with different irrigants. The heavy metal Be was not seen in any of the samples. Sealapex showed the longest setting time in comparison to other test sealers. Heavy metals were most present in Sealapex, followed by AH Plus, Tubli-Seal, and MTA Fillapex. MTA Fillapex was seen to have the shortest setting time, and heavy metal composition was least affected on interaction with different commonly used endodontic irrigants. Further, this study provides significant insight into the influence of different endodontic irrigants on interaction with different base endodontic sealers, which has not been reported previously, and future studies should emphasize endodontic irrigant-sealer interactions and their possible effects in the long run.

Recent update on potential cytotoxicity, biocompatibility and preventive measures of biomaterials used in dentistry

Dental treatment is provided for a wide variety of oral health problems like dental caries, periodontal diseases, periapical infections, replacement of missing teeth and orthodontic problems. Various biomaterials, like composite resins, amalgam, glass ionomer cement, acrylic resins, metal alloys, impression materials, bone grafts, membranes, local anaesthetics, etc., are used for dental applications. The physical and chemical characteristics of these materials influence the outcome of dental treatment. It also impacts on the biological, allergic and toxic potential of biomaterials. With innovations in science and their positive results, there is also a need for awareness about the biological risks of these biomaterials. The aim of dental treatment is to have effective, yet safe, and long-lasting results for the benefit of patients. For this, it is important to have a thorough understanding of biomaterials and their effects on local and systemic health. Materials used in dentistry undergo a series of analyses before their oral applications. To the best of our knowledge, this is the first and original review that discusses the reasons for and studies on the toxicity of commonly used biomaterials for applications in dentistry. It will help clinicians to formulate a methodical approach for the selection of dental biomaterials, thus providing an awareness for forecasting their risk of toxic reactions.

Biological Properties of Experimental Methacrylate-Based Sealers Containing Calcium Phosphates

This study aimed to evaluate, in vitro and in vivo, the biocompatibility of experimental methacrylate-based endodontic sealers containing α-tricalcium phosphate (α-TCP) or nanostructured hydroxyapatite (HAp). Experimental methacrylate-based dual-cure sealers with the addition of α-TCP or HAp, at 10%wt were formulated and compared to AH Plus (AHP). Cell viability was assessed by 3-(4,5-dimethyl-thiazoyl)-2,5-diphenyl-tetrazolium bromide (MTT), and sulforhodamine B (SRB). Sealers were implanted in rats' subcutaneous tissue and histologically evaluated. Bioactivity was assessed by alkaline phosphatase enzyme activity (ALP) and Alizarin Red (AR), using apical papillary cells (SCAPs), and by the bone deposition measured in surgical cavities on rats' femur filled with AH Plus or α-TCP. In both viability assays, HAp and AHP sealers were similar, and α-TCP presented lower viability compared to the others at MTT assay (p<0.05). A gradual decrease of the inflammatory response according to the periods was observed and AHP was the only that presented giant cells (7-day period). Collagen fibers condensation increased according to the periods, with no differences among sealers. There was an increase at ALP activity and mineralized nodules deposition according to periods. HAp and α-TCP presented higher values for ALP activity at 5 days and at 5, 10, and 15 days for AR and were different from AHP (p<0.05). α-TCP presented superior values at 10 and 15 days compared to HAp and AHP for AR (p<0.05). At 90 days, α-TCP and control (empty cavity) showed high bone deposition compared to AHP (p<0.05). α-TCP and HAp, in a methacrylate-based sealer, presented biocompatibility and bioactivity, with the potential to be used as endodontic sealers in clinical practice. Further investigations are required to gain information on the physicochemical properties of these sealers formulation before its clinical implementation.

Evaluation of the cytocompatibility of methacrylate resin-based root canal sealers with osteoblast-like cells

This study compared the cytocompatibilities of three methacrylate resin-based root canal sealers [MetaSEAL Soft (MSS), Hybrid Root SEAL (HRS), and Superbond Sealer (SBS)] in either freshly mixed or set conditions using the Kusa A1 osteoblastic cell line. The three sealers and an epoxy resin-based sealer (AH Plus; AHP) were extracted in culture medium; cell growth and osteogenic properties were analyzed. Cell adhesion on set sealers was analyzed with scanning electron microscopy. The respective extents of cell growth were as follows in freshly mixed and set sealer extracts: SBS>MSS>AHP>HRS and SBS=AHP>MSS>HRS. Light irradiation of MSS and HRS increased the cell growth of set sealer extracts. Set SBS, MSS, and AHP did not alter expression of osteogenic genes or formation of mineralized nodules. Attached cells were observed only on SBS. In conclusion, the four sealers exhibited varying degrees of compatibility to osteoblasts; SBS and HRS were the most and least compatible, respectively.

Sealing Ability of Endodontic Cements: An In Vitro Study

The root canal system must be obturated using a hermetic seal to prevent the penetration of microorganisms and bacterial toxins into the endodontic system. The principles of adhesive dentistry have been increasingly used in endodontics. In fact, resin-based sealers are increasingly used. The objective of this study was to evaluate, in vitro, the sealing ability of resin cement in comparison with calcium hydroxide-based cement. Materials and Methods. Eighty root canals were prepared with the Tilos system and were randomly divided into four groups according to the filling material. The best combination was evaluated on the basis of its sealing ability. The dye infiltration degree was evaluated using both a stereomicroscope after diaphanization and the dye rise test. Results. A significant difference was observed between the four obturation systems with regard to the number of infiltrated walls (p=0.014) and the infiltration depth (p=0.025). The group of teeth obturated with EndoREZ® and EndoREZ® gutta cones differ significantly from the group obturated with EndoREZ® cement and gutta-percha cones in terms of apical sealing (p=0.011). A significant difference was also observed between the group of teeth obturated using EndoREZ® gutta cones and EndoREZ® cement and the group of teeth obturated with EndoREZ® cement (p=0.026). Conclusion. When used with EndoREZ® gutta cones, EndoREZ® cement showed the best sealing ability, particularly in the apical region. When used with gutta-percha cones, Acroseal and EndoREZ® cements exhibited similar sealing abilities.

Biocompatibility of Root Canal Sealers: A Systematic Review of In Vitro and In Vivo Studies

(1) Aim: To perform a systematic review of the literature on the biocompatibility of root canal sealers that encompasses the various types of sealers that are commercially available as well as both in vitro and in vivo evidence. (2) Methods: This systematic review has been registered in PROSPERO (ID 140445) and was carried out according to PRISMA guidelines using the following databases: PubMed, Cochrane Library, ClinicalTrials.gov, Science Direct, and Web of Science Core Collection. Studies published between 2000 and 11 June 2019 that evaluated cytotoxicity (cell viability/proliferation) and biocompatibility (tissue response) of root canal sealers were included. (3) Results: From a total of 1249 studies, 73 in vitro and 21 in vivo studies were included. In general, studies suggest that root canal sealers elicit mild to severe toxic effects and that several factors may influence biocompatibility, e.g., material setting condition and time, material concentration, and type of exposure. Bioactive endodontic sealers seem to exhibit a lower toxic potential in vitro. (4) Conclusions: The available evidence shows that root canal sealers exhibit variable toxic potential at the cellular and tissue level. However, the methodological heterogeneity among studies included in this systematic review and the somewhat conflicting results do not allow a conclusion on which type of sealer presents higher biocompatibility. Further research is crucial to achieve a better understanding of the biological effects of root canal sealers.

In Vitro Biocompatibility of Preheated Giomer and Microfilled-Hybrid Composite

Objective

The aim of this study was to evaluate cytotoxic potencies of two light cured composite materials after heating on different temperatures and cured directly and through CAD/CAM overlay.

Materials and methods

Composite materials (microfilled-hybrid Gradia Direct Posterior and Beautifil II) were heated in a Calset warming unit at three different temperatures (T1:37°C, T2:54°C, T3:68°C). A small amount of heated composite material was placed in a round mold (diameter 6mm; 0.65mm thick), covered with Mylar sheet, pressed and polymerized with Bluephase LED unit. One group of samples were polymerized directly, and the other group through 2mm thick CAD/CAM ceramic-reinforced polymer (CRP) and CAD/CAM lithium disilicate ceramic (LDC) overlay for 20 and 40 seconds. The polymerized samples were placed immediately after curing in a lymphocyte cell culture. The viability of peripheral blood lymphocytes was evaluated using a dye exclusion technique by simultaneous staining with ethidium bromide and acridine orange. Quantitative assessments were made by determination of the percentage of viable, apoptotic and necrotic cells. The Pearson chi-square test was used for statistical analysis.

Results

In case of 20 seconds polymerization, the highest number of viable cells polymerization were recorded when materials were heated at 37°C (T1), while in case of 40 seconds polymerization, the highest number of viable cells were recorded when the materials were heated at 54°C (T2). The samples polymerized through CAD/CAM overlays showed less cytotoxicity than samples polymerized directly.

Conclusion

Apart from composite material composition, the cell viability was also influenced by curing time, temperature of pre-heating and polymerization pattern.

Evaluation of apoptosis/necrosis and cytokine release provoked by three root canal sealers in human polymorphonuclears and monocytes

AIM

To evaluate the in vitro cytotoxicity and cytokine release of three fresh root canal sealers and to determine the type of cell death they induce.

METHODOLOGY

The sealers tested were Sealer 26 (S26), AH Plus (AHP), and Endosequence BC Sealer (END). Fresh sealers were cultivated in contact with monocytes and polymorphonuclears (PMNs) obtained from the peripheral blood of humans. Cell viability, apoptosis and necrosis were analysed at 4 h (PMNs) or 24 h (monocytes) using Annexin-V and propidium iodide in a cytometer. The supernatants were used to quantify Interleukin (IL)-4, IL-6, IL-10, IL-12 and tumour necrosis factor-α (TNF-α) in monocytes and IL-8 in PMNs by ELISA. One-way ANOVA and the Tukey post-test were used to compare data for cytotoxicity, and the multiple T-test was used to determine the differences between sealers in the release of cytokines that were statistically significant.

RESULTS

After 4 h of treatment, S26 was associated with greater cell viability than the other sealers (P < 0.05) in the PMN culture and had similar values of necrosis as END (P > 0.05). After 24 h of treatment, AHP and END had greater monocyte cell viability than S26 (P < 0.05), which had more necrosis (P < 0.05). END had the lowest levels of IL-12 compared to the other sealers (P < 0.05) and higher levels of IL-6 compared to S26 (P < 0.05). The tested sealers did not differ in the release of IL-8, IL-10, TNF-α and IL-4 (P > 0.05).

CONCLUSIONS

The effect of toxic agents released varied depending on the cell type studied. The composition of the sealers appeared to alter the form of self-regulation in the production of these cytokines by cells.

Cytotoxicity of Two Experimental Epoxy Resin-Based Sealers

INTRODUCTION

Many endodontic sealers are available, but search for the ideal sealer continues. This study aimed to assess the cytotoxicity of two experimental endodontic sealers in comparison with AH-26 resin sealer.

METHODS AND MATERIALS

This in vitro study was conducted on conventional and experimental root canal sealers: AH-26, an epoxy resin experimental sealer A (ES-A) composed of calcium tungstate, zirconium oxide, aerosil, bismuth oxide, titanium oxide, hexamine and an epoxy resin and experimental sealer B (ES-B) with compositions similar to ES-A except for the presence of imidazoline as a catalyst. The experimental sealers containing nano-particles were mixed with 37.5% of an epoxy resin. The extraction of five samples of each experimental sealer (A, B) and AH-26 sealer were subjected to MTT assay in the form of set and fresh at 1, 24 and 72 h with 1, 10, 100% dilution according to the International Standard ISO:10993-2012. Data were analyzed using the one-way ANOVA.

RESULTS

The set ES-A had the least cytotoxicity from the first hour but the cytotoxicity of ES-B and AH-26 extraction decreased over time. In fresh form, except for 100% concentration, ES-A showed the least cytotoxicity compared to the other two sealers.

CONCLUSION

All three sealers had high cytotoxicity in 100% concentration but had low cytotoxicity in 10% and 1% concentrations.

Neurotoxicity evaluation of three root canal sealers on cultured rat trigeminal ganglion neurons

Background

The aim of this study was to investigate the possible neurotoxic effects of 3 root canal sealers (RCSs) (AH Plus, GuttaFlow, iRoot SP) on cultured rat trigeminal ganglion (TG) neurons.

Material and Methods

Primary cultures of TG neurons were obtained from 1 to 2-day old rats. Freshly mixed RCSs were incubated in sterile phosphate buffered saline and cells were incubated with supernatants of the RCSs for different time intervals (1-, 3-, 6- and 24-h; 1 or 1/10 diluted) and viability/cytotoxicity was tested by counting the number of live cells. Pair of dishes with cells from the same culture incubated with only culture medium was considered as negative controls. Cell images were captured and acquired at x200 magnification using a microscope equipped with a camera using special image program. The viable cells were manually counted assigned from the images for each dose and incubation duration. Data was analysed by using 1-way analysis of variance with Tukey post hoc tests.

Results

There was no significant change in cell viability after short duration of incubation (1- and 3-h) with the supernatant of any of RCSs, except for undiluted-AH Plus at 3-h. When AH Plus was compared with other RCSs, for diluted supernatants, there was only significant difference between iRoot SP and AH Plus at 24-h (P<0.05). Whereas undiluted-AH Plus was significantly more cytotoxic for 3-, 6- and 24-h periods as compared to respective incubation periods of undiluted other groups (P<0.05). GuttaFlow groups had similar neurotoxic effect on cells for all test periods.

Conclusions

All tested RCSs exhibited a variable degree of neurotoxicity on these primary sensory neurons of orofacial tissues, depending on their chemical compositions. GuttaFlow and iRoot SP evoked a less toxic response to TG cells than AH Plus.

Key words:Neurotoxicity, trigeminal ganglia, cell culture, root canal sealer, AH Plus, GuttaFlow, iRoot SP.

A comparative evaluation of cytotoxicity of root canal sealers: an in vitro study

OBJECTIVES

The objective of this in vitro study was to evaluate and compare the cytotoxicity of four different root canal sealers i.e. Apexit Plus (Ivoclar Vivadent), Endomethasone N (Septodont), AH-26 (Dentsply) and Pulpdent Root Canal Sealer (Pulpdent), on a mouse fibroblast cell line (L929).

MATERIALS AND METHODS

Thirty two discs for each sealer (5 mm in diameter and 2 mm in height) were fabricated in Teflon mould. The sealer extraction was made in cell culture medium (Dulbecco's Modified Eagle's Medium, DMEM) using the ratio 1.25 cm(2)/mL between the surface of the sealer samples and the volume of medium in a shaker incubator. Extraction of each sealer was obtained at 24 hr, 7th day, 14th day, and one month of interval. These extracts were incubated with L929 cell line and 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay was done. Two-way ANOVA for interaction effects between sealer and time and Post-hoc multiple comparison using Tukey's test across all the 16 different groups were used for statistical analysis.

RESULTS

Apexit Plus root canal sealer was significantly less toxic than other sealers (p < 0.05) and showed higher cellular growth than control. Endomethasone N showed mild cytotoxicity. AH-26 showed severe toxicity which became mild after one month while Pulpdent Root Canal Sealer showed severe to moderate toxicity.

CONCLUSIONS

Apexit Plus was relatively biocompatible sealer as compared to other three sealers which were cytotoxic at their initial stages, however, they became biocompatible with time.

Evaluation of the responses of MHC class II molecule-expressing cells and macrophages to epoxy resin-based and 4-META-containing, methacrylate resin-based root canal sealers in rat subcutaneous tissue

Major histocompatibility complex (MHC) class II molecule-expressing cells and macrophages play a pivotal role in mediating the host tissue response to biomaterials. This study investigated the responses of these cells to epoxy resin-based and 4-META-containing, methacrylate resin-based endodontic sealers (AH Plus and MetaSEAL respectively) in rat connective tissue. Silicone tubes loaded with one of the sealers or solid silicone rods (control) were subcutaneously implanted in male Wistar rats for three time periods of 7, 14, or 28 days. Tissue specimens were immunoperoxidase-stained for MHC class II molecules and CD68 (a general macrophage marker). Results showed that AH Plus-implanted tissue displayed significantly more MHC class II-positive cells than the control at 14 and 28 days, whereas MetaSEAL-implanted tissue showed significantly more CD68-positive cells than both AH Plus-implanted tissue and the control at all time periods. It was concluded that the epoxy resin-based sealer induced the infiltration of MHC class II molecule-expressing cells, whereas 4-META-containing, methacrylate resin-based sealer elicited macrophage infiltration.

Long-term cytotoxic effects of contemporary root canal sealers

OBJECTIVES

The aim of the present study was to investigate the effects of root canal sealers on the cytotoxicity of 3T3 fibroblasts during a period of 5 weeks.

MATERIAL AND METHODS

Fibroblasts (3T3, 1×105 cells per well) were incubated with elutes of fresh specimens from eight root canal sealers (AH Plus, Epiphany, Endomethasone N, EndoREZ, MTA Fillapex, Pulp Canal Sealer EWT, RoekoSeal and Sealapex) and with elutes of the same specimens for 5 succeeding weeks after immersing in simulated body fluid. The cytotoxicity of all root canal sealers was determined using the MTT assay. Data were analyzed using ANOVA and Tukey's test.

RESULTS

RoekoSeal was the only sealer that did not show any cytotoxic effects (p<0.05). All the other tested sealers exhibited severe toxicity initially (week 0). MTA Fillapex remained moderately cytotoxic after the end of experimental period. Toxicity of the other tested sealers decreased gradually over time. The evaluated root canal sealers presented varying degrees of cytotoxicity, mainly in fresh mode.

CONCLUSIONS

RoekoSeal had no cytotoxic effect both freshly mixed and in the other tested time points. MTA Fillapex was associated with significantly less cell viability when compared to the other tested root canal sealers.

Cytotoxicity evaluation of three resin-based sealers on an L929 cell line

Background:

Endodontic sealers usually come in contact with adjacent tissues and their biocompatibility is key in a successful treatment. The purpose of this study was to assess the cytotoxicity of three resin-based sealers, namely AH Plus, EndoREZ, and Epiphany in set and fresh states on an L929 cell line.

Materials and Methods:

In this in vitro experimental study, the materials were mixed according to the manufacturers’ instructions, and were divided into two groups, fresh and set. The elutes of materials were prepared separately and were incubated with L929 fibroblasts for 1 hour, 24 hours, and 72 hours. Pulp Canal Sealer and Dulbecco's Modified Eagle Medium (DMEM) served as positive and negative controls respectively. Cell viability was evaluated by MTT assay ([3-4,5-dimethyl thiazol-2-yl]-2,5-diphenyltetrazolium bromide succinate), after 1 hour, 24 hours, and 72 hours. The data were analyzed by analysis of variance (ANOVA), and Tukey multiple comparison test.

Results:

After 1 hour, fresh Epiphany and fresh AH Plus were significantly more cytotoxic than their set samples. No significant difference was perceived between cytotoxicity of fresh state of sealers and positive control, or between set state and negative control. After 24 hours, both fresh and set samples of all materials were significantly more cytotoxic than the negative control group, and were less cytotoxic than the positive control group. After 72 hours, the fresh and set samples of all materials were as cytotoxic as the positive control group. At each time point, no significant difference was perceived among different materials in terms of cell viability.

Conclusion:

The observed differences among the cytotoxicity of AH Plus, EndoREZ, and Epiphany did not reach a significant level at comparable time points after exposure.

Cytotoxicity of root canal sealers on endothelial cell cultures

This study evaluated, in vitro, the cytotoxicity of six root canal sealers after 12, 24 and 72 h of contact time, using an endothelial ECV-304 cell line. The MTT assay was used for analysis of cell viability. Twelve specimens of each sealer were prepared and randomly assigned to 6 groups according to the commercial brands (n=4/time). A control group was also formed, which was not subjected to the contact with sealers. To assess the effects of sealers on endothelial cells, the specimens were placed in culture plate wells and incubated at 37°C with 5% CO2 and 100% humidity. MTT assays were performed in quadruplicate after 12, 24 and 72 h of contact of the sealer specimens with monolayers. Statistical analysis was performed by two-way ANOVA with Bonferroni post-hoc test at a significance level of 5%. Analysis of absorbance in the experimental groups showed that GuttaFlow presented the lowest cytotoxicity, with a mean absorbance of 0.048, followed by Pulp Canal Sealer (0.038), Sealer 26 (0.038), Endo Densell (0.036) and Pulp Fill (0.035). The control group had a mean absorbance of 0.098. Based on the results, Endofill and GuttaFlow were the most and the least cytotoxic sealers, respectively.

Effects of an experimental calcium aluminosilicate cement on the viability of murine odontoblast-like cells

INTRODUCTION

Quick-setting calcium aluminosilicate cement with improved washout resistance is a potential substitute for calcium silicate cements in endodontics. This study examined the effect of an experimental calcium aluminosilicate cement (Quick-Set; Primus Consulting, Bradenton, FL) on the viability of odontoblast-like cells.

METHODS

The biocompatibility of Quick-Set and white ProRoot MTA (WMTA; Dentsply Tulsa Dental Specialties, Tulsa, OK) cements and their eluents was evaluated using a murine dental papilla-derived odontoblast-like cell line (MDPC-23); 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to examine the effects of the 2 hydraulic cements on mitochondrial metabolic activity. Flow cytometry and confocal laser scanning microscopy were used to identify the effects of the 2 cements on cell death-induced plasma membrane permeability to fluorescent dyes and DNA stains.

RESULTS

After the first week of immersion in culture medium, Quick-Set and WMTA were more cytotoxic than the Teflon-negative control (P < .05), and the cells exhibited more apoptosis/necrosis than Teflon (P < .05). After the second week of immersion, the 2 cements were as biocompatible as Teflon (P > .05), with cells exhibiting minimal apoptosis/necrosis. Eluents from the set cements at 1:1 dilution were significantly more cytotoxic that eluents at 1:10 or 1:100 dilution (P < .05).

CONCLUSIONS

Quick-Set and WMTA exhibited similar cytotoxicity profiles. They possess negligible in vitro toxicologic risks after time-dependent elution of toxic components.

An in vitro evaluation of the growth of human periodontal ligament fibroblasts after exposure to a 4-META-containing methacrylate-based endodontic sealer

INTRODUCTION

In this study we evaluated the cytotoxic effects of MetaSEAL, a 4-META-containing meth-acrylate-based endodontic sealer, on human periodontal ligament (HPDL) fibroblasts. There are a limited number of studies on the cytotoxic effects of MetaSEAL, and there are no studies on the cytotoxic effects of MetaSEAL on cells it might come into contact with in vivo.

METHODS

MetaSEAL concentrations of 25, 50, 100, 200, 400, and 800 μg/mL were exposed to HPDL fibroblast cultures and evaluated at 1, 3, 7, 14, and 21 days. Controls included untreated cells and cells treated with ethanol, the vehicle for MetaSEAL suspension. Crystal violet staining in 24-well plates and the fluorescence-based CyQUANT Cell Proliferation Assay in 96-well plates assessed fibroblast viability.

RESULTS

Significant cytotoxicity against HPDL growth by MetaSEAL was both time- and concentration-dependent. At day 1 there were no significant cytotoxic effects, whereas by day 3, 800 μg/mL concentration, by day 7, 200, 400, and 800 μg/mL concentrations, and by day 14, 50, 100, 200, 400, and 800 μg/mL concentrations were significantly cytotoxic. By day 21, all concentrations were significantly cytotoxic. These findings were confirmed by both the crystal violet and CyQUANT assays.

CONCLUSIONS

MetaSEAL endodontic sealer has increasing HPDL cytotoxicity with both concentration and time exposure.

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.

Biocompatibility of four root canal sealers: a histopathological evaluation in rat subcutaneous connective tissue

The aim of this study was to evaluate the subcutaneous biocompatibility of: Epiphany, AH Plus, Pulp Canal Sealer and Sealapex root canal sealers. Sixty rats were randomly assigned to 4 groups, according to the sealer. Polyethylene tubes containing the tested materials were inserted into the connective tissue. The implants were removed after 7, 15 and 30 days, and the tissue samples were processed, stained and examined by light microscopy. The descriptive analysis considered: thickness of the fibrous capsule, severity of the inflammatory reaction, and presence of giant cells. After 7 days, all sealers induced moderate to severe inflammatory reaction. After 15 days, Epiphany and AH Plus sealers showed a moderate inflammatory reaction, while Pulp Canal Sealer and Sealapex induced severe and mild inflammatory reactions, respectively. After 30 days, mild inflammatory reactions were observed for Epiphany, Sealapex and AH Plus. Sealapex induced the lowest inflammatory response at all evaluation periods, and only Pulp Canal Sealer did not show a decreased in the inflammatory reaction over time.

Subcutaneous connective tissue reaction to methacrylate resin-based and zinc oxide and eugenol sealers

INTRODUCTION

An evaluation was made of the connective tissue reaction in rats after subcutaneous implantation of methacrylate resin-based sealers (EndoREZ [Ultradent Products, Inc, South Jordan, UT] with a polymerization accelerator and RealSeal [Sybron Dental Specialties, Orange, CA]) and Pulp Canal Sealer (Sybron Dental Specialties), a zinc oxide and eugenol-based sealer used as the control.

METHODS

Silicone tubes containing the test materials were implanted in 24 Wistar rats. Solid silicone rods of the same size served as the negative controls. After 10, 30, and 90 days, the animals (n = 8 per period) were euthanized and the implants with surrounding tissues dissected and processed for routine histological evaluation. A four-category evaluation system was used to measure and record the microscopic observations according to the thickness of a fibrous capsule, the vascular changes, and the various types of inflammatory cells.

RESULTS

Initially, a severe inflammatory reaction was observed of the soft tissues in direct contact with both EndoREZ/Accelerator and Real Seal. The severity decreased over time and was resolved at the end of the experiment. Pulp Canal Sealer showed a severe tissue reaction for all observation periods. The negative controls showed an initial mild to moderate inflammatory reaction. After 30 days, healthy fibrous connective tissue was observed, which increased over time. After 10 days, no statistically significant differences between the experimental groups were observed. After 90 days, EndoREZ and RealSeal were statistically significantly less toxic than Pulp Canal Sealer (p > 0.05).

CONCLUSIONS

After 90 days, both methacrylate resin-based sealers were considered biologically acceptable when implanted in subcutaneous connective tissues of the rat. Pulp Canal Sealer remained toxic for the duration of the study.

Inflammatory suppression by endodontic sealers after aging 12 weeks In vitro

Dental endodontic sealers are in intimate contact with tissues around the root apex (periapical area) for extended periods. New endodontic sealers have been developed in the past decade, but the biological responses to many new products are not well documented. In this study, we assessed in vitro monocytic cytotoxic and inflammatory responses to several contemporary endodontic sealers. AH-Plus (AH), Pulp Canal Sealer (PC), Epiphany (EPH), Endo-Rez (ER), and an experimental Endo-Rez (ERx) were initially placed in buffered-saline for 12 weeks to simulate in vivo use. After "aging," specimens were placed in direct contact with THP1 monocytes for 72 h and their cytotoxicity (mitochondrial response; MTT) or ability to trigger or suppress cytokine secretion (ELISA; TNFalpha, IL1beta, IL=6; +/- lipopolysaccharide (LPS) exposure) were measured relative to Teflon (Tf) negative controls. Cellular responses among conditions were compared with ANOVA and Tukey post-hoc analysis (alpha = 0.05). Two of the five sealers, EPH and PC, still suppressed cell mitochondrial activity by 70% or more after 12 weeks of conditioning in saline. No sealer alone activated monocytic TNFalpha, IL1beta, or IL6 secretion (p > 0.05 vs. +LPS controls). When THP1 were activated by LPS after exposure to the sealers, differential suppression of TNFalpha, IL1beta, and IL6 secretion was observed for two of the five sealers tested. (EPH and PC) This data suggest that common endodontic sealers do not activate monocytic TNFalpha, IL1beta, and IL6 secretion in vitro by themselves, but degradation products of the sealers may suppress activation of monocytes.

Osteoblast response to dimethacrylate composites varying in composition, conversion and roughness using a combinatorial approach

Dimethacrylate polymers and composites are seeing increased usage in orthopedics. As these applications require the material to integrate with the surrounding tissues, direct contact cytotoxicity assays should be used to assess the biocompatibility. This study utilized a combinatorial testing platform to evaluate the cell response to dimethacrylate composites with a variety of properties on a single sample. MC3T3-E1 pre-osteoblasts were cultured directly on composites with varying filler content, filler type, degree of conversion (DC), and surface topography. Cell viability, density, and area depended on an interplay of the material properties, with low DC causing a reduction in cell area but having minimal effect on cell viability, high filler content causing an increase in cell density, and filler content/type altering the surface roughness as a function of DC. The combinatorial testing platform successfully quantified the effects of numerous material properties on several aspects of the osteoblast response.