Optimal Cytocompatibility of a Bioceramic Nanoparticulate Cement in Primary Human Mesenchymal Cells

Therapeutic Potential of Chlorhexidine-Loaded Calcium Hydroxide-Based Intracanal Medications in Endo-Periodontal Lesions: An Ex Vivo and In Vitro Study

Endo-periodontal lesions are challenging clinical situations where both the supporting tissues and the root canal of the same tooth are infected. In the present study, chlorhexidine (CHX)-loaded calcium hydroxide (CH) pastes were used as intracanal medications (ICMs). They were prepared and tested on pathogens found in both the root canal and the periodontal pocket. Exposure to 0.5% and 1% CHX-loaded ICMs decreased the growth of Porphyromonas gingivalis and was effective in eradicating or inhibiting an Enterococcus faecalis biofilm. CH was injected into the root canal of extracted human teeth immersed in deionized water. CHX-loaded ICMs resulted in the transradicular diffusion of active components outside the tooth through the apex and the lateral dentinal tubules, as shown by the release of CHX (from 3.99 µg/mL to 51.28 µg/mL) and changes in pH (from 6.63 to 8.18) and calcium concentrations (from 2.42 ppm to 14.67 ppm) after 7 days. The 0.5% CHX-loaded ICM was non-toxic and reduced the release of IL-6 by periodontal cells stimulated by P. gingivalis lipopolysaccharides. Results indicate that the root canal may serve as a reservoir for periodontal drug delivery and that CHX-based ICMs can be an adjuvant for the control of infections and inflammation in endo-periodontal lesions.

Perspectives on the Application of Nanomaterials in Medical and Dental Practices

A new field of study called nanotechnology concentrates on manipulating matter at atomic and molecular levels. Modern medicine may benefit tremendously from developments in the field of nanotechnology, and as a result, nanomedicine has emerged as a key location of education in the specific area of nanotechnology. This article aims to describe nanotechnology's possible applications in therapeutics. Nanotechnology and nanomedicine have allowed for the development of new dental materials that are stronger, more resistant to microbial seeding, etc. Other examples include high-strength denture bases, antimicrobial dental glue, aesthetic restorative materials comprised of small particles, and interface adorning for dental posts. Nanotechnology has been perfectly utilized in the medical industry for tissue engineering, biosensors, nanoscale diagnostic tools, and medication delivery using nanoparticles.

Biomimetic Approaches in Clinical Endodontics

In the last few decades, biomimetic concepts have been widely adopted in various biomedical fields, including clinical dentistry. Endodontics is an important sub-branch of dentistry which deals with the different conditions of pulp to prevent tooth loss. Traditionally, common procedures, namely pulp capping, root canal treatment, apexification, and apexigonesis, have been considered for the treatment of different pulp conditions using selected materials. However, clinically to regenerate dental pulp, tissue engineering has been advocated as a feasible approach. Currently, new trends are emerging in terms of regenerative endodontics which have led to the replacement of diseased and non-vital teeth into the functional and healthy dentine-pulp complex. Root- canal therapy is the standard management option when dental pulp is damaged irreversibly. This treatment modality involves soft-tissue removal and then filling that gap through the obturation technique with a synthetic material. The formation of tubular dentine and pulp-like tissue formation occurs when stem cells are transplanted into the root canal with an appropriate scaffold material. To sum up tissue engineering approach includes three components: (1) scaffold, (2) differentiation, growth, and factors, and (3) the recruitment of stem cells within the pulp or from the periapical region. The aim of this paper is to thoroughly review and discuss various pulp-regenerative approaches and materials used in regenerative endodontics which may highlight the current trends and future research prospects in this particular area.

Dentin Sialoprotein/Phosphophoryn (DSP/PP) as Bio-Inductive Materials for Direct Pulp Capping

Conventional direct pulp capping, such as calcium hydroxide (Ca(OH)₂) or silicate products, usually induces an inflammatory reaction to provoke pulp regeneration. Phosphophoryn (PP) and dentin sialoprotein (DSP), the two most abundant non-collagenous proteins in the dentin matrix, are responsible for dentin mineralization, pulp cell migration, and differentiation. Here we examined the PP and combined DSP/PP as bio-inductive pulp capping materials by in vitro and in vivo tests. Firstly, the effects of the PP dose on pulp cell migration and matrix protein expression were examined by an agarose bead test. Secondly, the role of recombinant DSP (recDSP) and recDSP/PP on stimulating DSP-PP transcript expression was examined by RT-PCR. DSPP mRNA was also knocked down by RNA interference (RNAi) to examine their functions on dentin matrix mineralization. Finally, we used ferret animal models to test PP and recDSP/PP acting as capping agents on in vivo pulp responses and reparative dentin formation. The result showed that intermediate-dose PP was the most effective to enhance cell migration and differentiation. RecDSP/PP strongly enhanced the DSP-PP transcript expression, while inhibition of DSPP mRNA expression by siRNAs partially or completely affected dental pulp cell mineralization. The in vivo results showed that intermediate-dose PP and recDSP/PP proteins induced less pulp inflammation and promoted reparative dentin formation. Contrarily, conventional calcium hydroxide induced severe pulp inflammation. With these findings, DSP and PP could serve as capping agents for pulp capping therapy.

Present status and future directions: Hydraulic materials for endodontic use

BACKGROUND

Hydraulic materials are used in Endodontics due to their hydration characteristics namely the formation of calcium hydroxide when mixing with water and also because of their hydraulic properties. These materials are presented in various consistencies and delivery methods. They are composed primarily of tricalcium and dicalcium silicate, and also include a radiopacifier, additives and an aqueous or a non-aqueous vehicle. Only materials whose primary reaction is with water can be classified as hydraulic.

OBJECTIVES

Review of the classification of hydraulic materials by Camilleri and the literature pertaining to specific uses of hydraulic cements in endodontics namely intra-coronal, intra-radicular and extra-radicular. Review of the literature on the material properties linked to specific uses providing the current status of these materials after which future trends and gaps in knowledge could be identified.

METHODS

The literature was reviewed using PUBMED, and for each clinical use, the in vitro properties such as physical, chemical, biological and antimicrobial characteristics and clinical data were extracted and evaluated.

RESULTS

A large number of publications were retrieved for each clinical use and these were grouped depending on the property type being investigated.

CONCLUSIONS

The hydraulic cements have made a difference in clinical outcomes. The main shortcoming is the poor testing methodologies employed which provide very limited information and also inhibits adequate clinical translation. Furthermore, the clinical protocols need to be updated to enable the materials to be employed effectively.

Periodontal Tissue Reaction Consecutive Implantation of Endodontic Materials and Subsequent Integration of Complex Oral Rehabilitation Treatments

Oral rehabilitation is a main branch of dentistry focused on diagnosing the patient’s problem and creating a treatment plan to restore aesthetics, recondition morphologically all components, and recover the functionality of the oral cavity. Biological compatibility of the materials used has a major importance, due to the direct contact with essential tissues, such as the soft and hard tissue of the periodontium and the potential influence on the outcome of the treatment. The present material aims to assess the inflammatory response after subcutaneous implantation of three materials frequently used in endodontics (Mineral Trioxide Aggregate—MTA, DiaRoot BioAggregate, and Sealapex). The evaluation of the reparative tissue reaction after 7, 30, and 60 days, respectively, subsequent to in vivo implantation, was carried out through electron microscopy imaging. Moreover, evaluation of the dynamics of the osteogenesis process was an indicator for the maintenance of internal homeostasis in the context of complex intraoral rehabilitation treatments that include fixed prosthodontics correlated with the particular periodontal-aesthetic aspects and completed by cranio-mandibular repositioning. Our study showed increased absolute values of alkaline phosphatase in all material-implanted cases (more pronounced in MTA and Bio Aggregate), highlighting that this enzyme could be an effective indicator of bone formation, which takes place after the material implantation, with the most significant elevated values at 30 days postoperatively.

Investigating the Antioxidant and Cytocompatibility of Mimusops elengi Linn Extract over Human Gingival Fibroblast Cells

Background-chlorhexidine (CHX) is most commonly used as a chemical plaque control agent. Nevertheless, its adverse effects, including teeth discoloration, taste alteration and calculus build-up, limit its use and divert us to medicinal herbs. The purpose of the study was to evaluate the phytochemical composition, antioxidant potential, and cytotoxic effects of Mimusops elengi Linn extract (ME) over normal human cultured adult gingival fibroblasts (HGFs). Methods-in vitro phytochemical screening, total flavonoid content, antioxidant potential by DPPH and Nitric Oxide (NO) radical scavenging activity, and cytotoxic effects of ME extracts over HGF were explored. The viability of HGF cells was determined using 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT), neutral red uptake, and trypan blue assay after treatment with different concentrations of CHX and ME (0.3125 to 10 µg/mL). Results-ME showed some alkaloids, glycosides, saponins and flavonoids exhibited relatively moderate-to-good antioxidant potential. Increasing the concentration of CHX and ME from 0.3125 to 10 µg/mL reduced cell viability from 29.71% to 1.07% and 96.12% to 56.02%, respectively. At higher concentrations, CHX reduced the viability of cells by 52.36-fold compared to ME, revealed by MTT assay. At 10 µg/mL concentration, the mean cell viability of CHX and ME-treated cells was 2.24% and 57.45%, respectively, revealed by a neutral red assay. The viability of CHX- and ME-treated HGF cells estimated at higher concentrations (10 µg/mL) using trypan blue assay was found to be 2.18% and 47.36%, respectively. A paired t-test showed significance (p < 0.05), and one-way ANOVA difference between the mean cell viability of CHX- and ME-treated cells at different concentrations. One-way ANOVA confirmed the significant difference between the viability of CHX- and ME-treated cells. Conclusions-The cytoprotective and antioxidant effects of ME emphasize its potential benefits. Therefore, it could emerge as a herbal alternative and adjunct to conventional oral hygiene methods, that can diminish periodontal tissue destruction.

In vitro biocompatibility and bioactivity of calcium silicate‑based bioceramics in endodontics (Review)

Calcium silicate-based bioceramics have been applied in endodontics as advantageous materials for years. In addition to excellent physical and chemical properties, the biocompatibility and bioactivity of calcium silicate-based bioceramics also serve an important role in endodontics according to previous research reports. Firstly, bioceramics affect cellular behavior of cells such as stem cells, osteoblasts, osteoclasts, fibroblasts and immune cells. On the other hand, cell reaction to bioceramics determines the effect of wound healing and tissue repair following bioceramics implantation. The aim of the present review was to provide an overview of calcium silicate-based bioceramics currently applied in endodontics, including mineral trioxide aggregate, Bioaggregate, Biodentine and iRoot, focusing on their in vitro biocompatibility and bioactivity. Understanding their underlying mechanism may help to ensure these materials are applied appropriately in endodontics.

Comparison of in vitro biocompatibility and antibacterial activity of two calcium silicate-based materials

This study is aimed at comparing and evaluating the biocompatibility and antibacterial activities of mineral trioxide aggregate (MTA) and iRoot BP Plus as novel retro-filling materials. Discs of both materials were prepared and incubated for 72 h to obtain material extracts in medium. Flow cytometry and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay were used to assess the rate of apoptosis and proliferation of human periodontal ligament stem cells (hPDLSCs) when exposed to eluates of both materials. The expression levels of alkaline phosphatase, collagen type I, osteocalcin, Runt-related transcription factor-2, and Osterix were tested for evaluating the osteogenic differentiation of hPDLSCs. The antibacterial activities of both materials were compared by the direct contact test. The hPDLSCs stimulated by MTA or iRoot BP Plus eluates showed significantly higher cell viability than that of the control group with no eluates. No significant differences were observed among the percentages of necrotic and apoptotic cells stimulated by MTA and iRoot BP Plus eluates and the control group. The expression of all osteogenic differentiation markers of hPDLSCs in both experimental groups were significantly higher than those of the control group, while the increment values in MTA group were significantly higher than those of the iRoot BP Plus group. The antibacterial activity against Enterococcus faecalis showed no significant difference between MTA and iRoot BP Plus. Therefore, both materials may be suitable for retro-filling applications.

Histological Evaluation of Periradicular Tissue Inflammatory Reactions and Calcified Tissue Formations After Implantation of Experimental Calcium Silicate and Hydroxyapatite Based Nanostructural Cements Into Root Canals of Rabbits Teeth

The aim of the study was to evaluate inflammatory tissue reactions and the formation of calcified tissue after implantation of experimental nanostructured calcium silicate cement (CS) and hydroxyapatite with calcium silicate cement (HA-CS) into root canals of rabbits’ teeth. The study was conducted on four rabbits of the genus Oryctolagus cuniculus. After instrumentation and irrigation, the root canals of the central incisors were dried and filled with CS, HA-CS and control material (MTA Angelus). The animals were sacrificed after 28 days. After histological preparation and hematoxylin-eosin staining, tissue samples were evaluated for the intensity and extension of inflammatory tissue reaction; continuity, morphology and thickness of the newly formed calcified tissue; and presence of giant cells, materials particles and microorganisms. Kruskal Wallis and Dunn’s post hoc test were used for data analysis (α=0.05). There were no significant differences in the intensity of inflammatory reactions between CS, HA-CS and MTA control. HA-CS showed significantly better results than MTA and CS with respect to continuity of the newly formed calcified tissue (P=0.003 and P=0.010, respectively). Significant differences in thickness of the calcified tissue existed between CS and MTA (P=0.004) and between HA-CS and MTA (P=0.012). Application of CS and HA-CS resulted in minimal inflammatory tissue response, similar to the MTA control. CS and HA-CS were more efficient than MTA in supporting hard tissue formation. The best organized newly formed calcified tissue was seen after HA-CS application.

iRoot SP Promotes Osteo/Odontogenesis of Bone Marrow Mesenchymal Stem Cells via Activation of NF-κB and MAPK Signaling Pathways

The regeneration of bone and tooth tissues, and related cellular therapies, has attracted widespread attention. Bone marrow mesenchymal stem cells (BMSCs) are potential candidates for such regeneration. iRoot SP is a premixed bioceramic root canal sealer widely used in clinical settings. However, the effect of iRoot SP on the biological features of BMSCs has not been elucidated. In the present study, we found that 0.2 mg/ml iRoot SP conditioned medium promoted osteo/odontogenic differentiation and enhanced mineralization of BMSCs without affecting the proliferative ability. Mechanistically, the NF-κB and MAPK signaling pathways were activated in SP-treated BMSCs, and differentiation was inhibited when cultured with the specific inhibitor. Taken together, these findings demonstrate that iRoot SP promotes osteo/odontogenic differentiation of BMSCs via the NF-κB and MAPK signaling pathways, which could provide a new theoretical basis for clinical applications of iRoot SP and a new therapeutic target for the regeneration of bone and tooth tissue in the future.

Manoeuvrability and biocompatibility of endodontic tricalcium silicate-based putties

OBJECTIVES

The present study evaluated the indentation depth, storage modulus and biocompatibility of an experimental endodontic putty designed for endodontic perforation repair and direct pulp-capping (NeoPutty). The results were compared with the properties associated with the commercially available EndoSequence BC RRM Putty (ES Putty).

METHODS

Indentation depth was measured by a profilometer following indentation with the 1/4 lb Gilmore needle. Elastic modulus was evaluated using a strain-controlled rheometer. The effects of eluents derived from these two putties were examined on the viability and proliferation of human dental pulp stem cells (hDPSCs) and human periodontal ligament fibroblasts (hPDLFs), before (1 st testing cycle) and after complete setting (2nd testing cycle).

RESULTS

The ES Putty became more difficult to ident and acquired a larger storage modulus after exposure to atmospheric moisture. Biocompatibility results indicated that both putties were relatively more cytotoxic than the bioinert Teflon negative control, but much less cytotoxic than the zinc oxide-eugenol cement negative control. NeoPutty was less cytotoxic than ES putty in the 1st testing cycle, particularly with hDPSCs. Both putties exhibited more favourable cytotoxicity profiles after complete setting.

CONCLUSIONS

NeoPutty has a better window of maneuverability after exposure to atmospheric moisture. From an in vitro cytotoxicity perspective, the NeoPutty may be considered more biocompatible than ES putty.

CLINICAL SIGNIFICANCE

The experimental NeoPutty is biocompatible and is capable of reducing the frustration of shortened shelf life when jar-stored endodontic putties are exposed to atmospheric moisture during repeated opening of the lid for clinical retrieval.

GuttaFlow® Bioseal Cytotoxicity Assessment: In Vitro Study

The sealers used for root canal treatment should be biocompatible for the peri-radicular tissues, to evaluate the cytotoxic effects of GuttaFlow® bioseal sealer and to compare them with AH26® epoxy resin. Culture media were conditioned with the GuttaFlow® bioseal and AH26® pellets. MDPC-23 odontoblast cell cultures were treated with conditioned medium and serial dilutions. To evaluate the metabolic activity and cellular viability, the MTT and SRB assays were performed. To determine the production of reactive oxygen species, the DHE and DCF-DA probes were used. Cell cycle and cell-death types were assessed by cytometry, and to evaluate the mineralization capacity, the Alizarin Red S coloration was used. Statistical analysis was performed using analysis of variance (ANOVA) when normality was found and Kruskal-Wallis on the opposite case. For the comparison with normality values, the Student t-test was used. Cells exposed to the GuttaFlow® bioseal conditioned medium maintained high metabolic activities, except at higher concentrations. Likewise, viability was maintained, but a significant decrease was observed after exposure to the highest concentration (p < 0.001), associated with cell death by late apoptosis and necrosis. When cell cultures were exposed to AH26®, metabolic activity was highly compromised, resulting in cell death. An imbalance in the production of peroxides and superoxide anion was observed. GuttaFlow® bioseal showed higher biocompatibility than AH26®.

Cytocompatibility of filling pastes by primary teeth root simulating model

Evaluate the cytocompatibility of Calen^®/ZO, Calcicur^®, Vitapex^®, Endoflas^®, and zinc oxide/eugenol-based (ZOE) root canal pastes (RCP) to human primary osteoblasts (HPO) through a simplified model for primary teeth. The model employed pipette tips filled with 0.037 g of paste, exposed to 185 µL of culture medium for 24 h (n = 6). Release of components was analysed by Proton Nuclear Magnetic Resonance Spectroscopy (¹H-NMR). HPO were exposed to conditioned media for 24 h. Cell viability was assessed by cell density and metabolic activity, and release of interleukin 6 (IL-6), vascular endothelial growth factor (VEGF) and fibroblast growth factor (bFGF) by immunological assay. Physicochemical properties and antimicrobial efficacy were also evaluated. ¹H-NMR spectra analysis showed similarity between ZOE, Endoflas^®, Calcicur^®, and Vitapex^® compared to Calen^®/ZO and positive control, which showed distinct released components. Calen^®/ZO and Calcicur^® exhibited high alkaline pH in all periods and showed similar solubility. Calen^®/ZO, ZOE, and Vitapex^® showed similar flow rate. Calen^®/ZO, Calcicur^®, and Vitapex^® did not exhibit antimicrobial efficacy. Calen^®/ZO presented cytotoxicity (p < 0.05). Pastes did not increase IL-6 release compared to control. Apart from Vitapex^®, all pastes significantly induced VEGF/bFGF release. Interactive effects among released products may affect biological response to filling pastes. Calcicur^®, ZOE, Endoflas^® and Calen^®/ZO presented good to moderate cytocompatibility, with low impact on pro-inflammatory cytokine release and induction of growth factors of interest to tissue repair. This simplified model, specific for the evaluation of the cytocompatibility of RCPs on primary teeth, suggests how these pastes might contribute to bone repair in clinical situations of apical periodontitis in children.

MTT versus other cell viability assays to evaluate the biocompatibility of root canal filling materials: a systematic review

OBJECTIVES

This systematic review aimed to compare the cytotoxicity of root canal filling materials (RCFMs) assessed using tetrazolium salt-based tests (TSBT), including the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, with those obtained using other cell viability assays.

METHODS

A search was performed on PubMed, Scopus, Web of Science and OpenGrey up to March 2019, followed by a manual search. According to the Participants, Exposure, Comparator and Outcomes (PECO) criteria, in vitro studies that evaluated the cytotoxic effect of RCFMss on animal and/or human cells through TSBT and at least one other viability assay were compared. The methodological quality of selected papers was assessed using ToxRTool^® and SciRAP^® . Data were analysed using Wilcoxon's signed-rank test for paired samples and linear weighting kappa.

RESULTS

A total of 230 non-duplicated records were identified. After applying the eligibility criteria, 55 studies were selected for methodological evaluation, seven were selected by manual searching, 22 were excluded for methodological reasons, and 40 were included. A total of 410 comparisons were performed between TSBT and distinct cell viability tests (DCVT). MTT had moderate concordance with DCVT using human cells (n = 138 samples) (P = 0.507; k = 0.4225) and animal cells (n = 122 samples) (P = 0.124; k = 0.5775). XTT had good concordance using human (n = 110 samples) (P = 0.507; k = 0.6336) and animal cells (n = 12 samples) (P = 0.564; k = 0.6604). MTT, XTT, WST and MTS assays showed moderate concordance with DCVT (n = 410 samples) (P = 0.375; k = 0.5138) and complete agreement in 226 samples.

DISCUSSION

The included studies had methodological heterogeneity that was minimized by the systematic review methodology.

CONCLUSIONS

MTT and XTT do not cause over- or underestimation of cell viability during cytotoxicity screening of root canal filling materials, implying that these assays can be considered reliable for this purpose. Nonetheless, the development of protocols for the cytotoxic screening of these materials on 3D tissue-like cultures aiming to improve their predictability in the clinical scenario is suggested.

In Vitro Effect of Putty Calcium Silicate Materials on Human Periodontal Ligament Stem Cells

New bioactive materials have been developed for retrograde root filling. These materials come into contact with vital tissues and facilitate biomineralization and apical repair. The objective of this study was to evaluate the cytocompatibility and bioactivity of two bioactive cements, Bio-C Repair (Angelus, Londrina, Pr, Brazil) and TotalFill BC RRM putty (FGK, Dentaire SA, La-Chaux-de-fonds, Switzerland). The biological properties in human periodontal ligament stem cells (hPDLSCs) that were exposed to Bio-C Repair and TotalFill BC RRM putty were studied. Cell viability, migration, and cell adhesion were analyzed. Moreover, qPCR and mineralization assay were performed to evaluate the bioactivity potential of these cements. The results were statistically analyzed using ANOVA and the Tukey test (p < 0.05). It was observed that cell viability and cell migration in Bio-C Repair and TotalFill BC RRM putty were similar to the control without statistically significant differences, except at 72 h when TotalFill BC RRM putty was slightly lower (p < 0.05). Excellent cell adhesion and morphology were observed with both Bio-C Repair and TotalFill BC RRM putty. Both cements promoted the osteo- and cementogenic differentiation of hPDLSCs. These results suggest that Bio-C Repair and TotalFill BC RRM putty are biologically appropriate materials to be used as retrograde obturation material.

Bone tissue response to an MTA-based endodontic sealer, and the effect of the addition of calcium aluminate and silver particles

AIM

To evaluate bone tissue reactions in rats to an MTA-based endodontic sealer with and without the addition of various concentrations of C3A or C3A + Ag.

METHODOLOGY

Bone tissue reactions were evaluated in 45 Wistar rats after 7, 30 and 90 days (n = 5 per period). Three surgical cavities were prepared on the right femur and filled with 0.2 mL MTA Fillapex, MTA Fillapex + C3A and C3A + Ag at various concentrations: AH Plus (Dentsply DeTrey GmbH, Konstanz, Germany), EndoSequence BC (Brasseler USA, Savannah, GA, USA) or no sealer (negative control). By the end of each experimental period, animals were randomly euthanized. The samples were histologically processed and analysed using a light microscope. The presence of inflammatory cells, fibres and hard tissue barrier formation was evaluated. Data were analysed statistically using nonparametric tests to compare the differences between groups. Multiple groups were compared using the Kruskal-Wallis and Mann-Whitney U-tests with a Bonferroni correction at P = 0.05.

RESULTS

The inflammatory response significantly decreased from 30 to 90 days (P < 0.05). Fibre condensation was similar amongst the groups at 07 and 30 days after intervention (P > 0.05). At 90 days, however, fibres were absent in most specimens of EndoSequence BC Sealer, AH Plus, MTA Fillapex and the control group, whilst they were still observed in samples of the modified sealers (P < 0.05). At 90 days, all specimens of AH Plus, EndoSequence BC Sealer and control group had complete formation of hard tissue barrier. In the MTA Fillapex group, as well as in the modified sealers groups, partial deposition of mineralized tissue was noticed.

CONCLUSION

The hypothesis tested that the incorporation of C3A and C3A + Ag particles to MTA Fillapex would improve bone tissue repair was partially accepted, since modified MTA Fillapex did not have the same repair potential as the commercial bioceramic material.

Effects of newly-developed retrograde filling material on osteoblastic differentiation in vitro

The aim of this study was to compare chemical properties and bioactivities of with mineral trioxide aggregate (MTA) and EndoSequence Root Repair Material (ERRM). After setting, surfaces of test materials were observed by scanning electron microscope (SEM). The pH and cell viability of materials were tested. Osteoblastic differentiation and alkaline phosphatase (ALP) activity were measured by quantitative real-time PCR and ALP staining. MTA showed spindle-shaped crystals while ERRM showed round-shaped crystals of various sizes. ERRM presented lower pH than MTA. Both materials showed good cell viabilities compared to the control. Expression levels of osteoblastic genes and ALP staining were increased significantly (p<0.05) in ERRM and MTA groups compared to those in the control group. In conclusion, ERRM and MTA both had effects on osteoblastic differentiation. Therefore, ERRM can be used as a desirable alternative to MTA for root-end filling material.

In Vitro and In Vivo Biocompatibility Of ReOss® in Powder and Putty Configurations

This study evaluated comparatively two configurations (powder and putty) of a composite biomaterial based on PLGA (Poly(lactide-co-glycolide)/nanoescale hydroxyapatite (ReOss®, Intra-Lock International) through microscopic morphology, in vitro cytotoxicity, biocompatibility and in vivo response as a bone substitute. SEM and EDS characterized the biomaterials before/after grafting. Cytocompatibility was assessed with murine pre-osteoblasts. Osteoconductivity and biocompatibility were evaluated in White New Zealand rabbits. Both configurations were implanted in the calvaria of eighteen animals in non-critical size defects, with blood clot as the control group. After 30, 60 and 90 days, the animals were euthanized and the fragments containing the biomaterials and controls were harvested. Bone blocks were embedded in paraffin (n=15) aiming at histological and histomorphometric analysis, and in resin (n=3) aiming at SEM and EDS. Before implantation, the putty configuration showed both a porous and a fibrous morphological phase. Powder revealed porous particles with variable granulometry. EDS showed calcium, carbon, and oxygen in putty configuration, while powder also showed phosphorus. After implantation EDS revealed calcium, carbon, and oxygen in both configurations. The materials were considered cytotoxic by the XTT test. Histological analysis showed new bone formation and no inflammatory reaction at implant sites. However, the histomorphometric analysis indicated that the amount of newly formed bone was not statistically different between experimental groups. Although both materials presented in vitro cytotoxicity, they were biocompatible and osteoconductive. The configuration of ReOss® affected morphological characteristics and the in vitro cytocompatibility but did not impact on the in vivo biological response, as measured by the present model.

Effects of Lectin (ScLL) on osteoclast-like multinucleated giant cells' maturation-A preliminary in vitro study

BACKGROUND/AIM

Lectin (ScLL) has been recently evaluated in the oral cavity due to its anti-inflammatory activities. ScLL could be a promising agent for blocking osteoclast activity and preventing root resorption. The aim of this study was to evaluate the effect of ScLL on the viability of the RAW 264.7 macrophage lineage, osteoclast-like maturation and the release of TNF-α and nitric oxide (NO).

MATERIALS AND METHODS

The viability of RAW 264.7 cells was determined by MTT and Alamar Blue assays after ScLL treatment for 24 hours. ScLL effects on RANKL-induced osteoclast-like maturation were assessed by tartrate-resistant acid phosphatase (TRAP) staining and F-actin ring formation. The supernatant was collected to detect the release of TNF-α using ELISA and NO using a nitrite assay.

RESULTS

ScLL suppressed osteoclast-like maturation by decreasing TRAP activity as well as F-actin ring formation. ScLL at 10 μg/mL showed the highest values of NO release compared with all other groups (P < .05). Lower levels of TNF-α were found for the negative control.

CONCLUSIONS

ScLL at 5 μg/mL suppressed osteoclast-like maturation in vitro and had no cytotoxic effect on RAW cell cultures.

Evaluation of the effects of the solution used for electrochemical dissolution of nickel-titanium endodontic files on dentine structure, microhardness and cell viability

AIM

To evaluate the effects of the [NaF 12 g L^-1  + NaCl 1 g L^-1 ] solution used in the electrochemical dissolution process of fractured endodontic files, as well as its NiTi-containing product, on dentine hardness, topography and human fibroblast viability.

METHODOLOGY

Sixty single-rooted human teeth were evaluated for dentine microhardness using the Vickers hardness test and the area and number of dentinal tubules by scanning electron microscopy. The samples were divided according to the dentine surface treatment: distilled water; 17% EDTA; [NaF 12 g L^-1  + NaCl 1 g L^-1 ]; and 17% EDTA + [NaF 12 g L^-1  + NaCl 1 g L^-1 ]. Thirty-six single-rooted human teeth were divided according to the irrigation protocol: Dulbecco's Modified Eagle's Medium + 10% foetal bovine serum; 5.25% NaOCl; [NaF 12 g L^-1  + NaCl 1 g L^-1 ]; and [NaF 12 g L^-1  + NaCl 1 g L^-1  + NiTi]. The extracts in contact with the apical foramen were used in the MTT assay to evaluate human fibroblast viability, with dilutions of 100%, 50%, 25% and 12.5%. Statistical tests used were paired t-tests, one-way anova, Tukey's test, Kruskal-Wallis test and Dunn's post-test.

RESULTS

The [NaF 12 g L^-1  + NaCl 1 g L^-1 ] solution did not modify dentine microhardness or the average dentinal tubule area. However, EDTA induced changes in dentine structure and microhardness (P < 0.05). The [NaF 12 g L^-1  + NaCl 1 g L^-1 ] solution, and its NiTi-containing product had lower cytotoxicity than NaOCl at dilutions of 25% and 50% (P < 0.01).

CONCLUSIONS

The [NaF 12 g L^-1  + NaCl 1 g L^-1 ] solution did not alter dentine microhardness or damage the dentine structure. It also demonstrated lower cytotoxicity than NaOCl.

Microstructure and chemical analysis of four calcium silicate-based cements in different environmental conditions

OBJECTIVE

The objective of this study was to analyze the microstructure and crystalline structures of ProRoot MTA, Biodentine, CEM Cement, and Retro MTA when exposed to phosphate-buffered saline, butyric acid, and blood.

METHODS AND MATERIALS

Mixed samples of ProRoot MTA, Biodentine, CEM Cement, and Retro MTA were exposed to either phosphate-buffered saline, butyric acid, or blood. Scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopic (EDX) evaluations were conducted of specimens. X-ray diffraction (XRD) analysis was also performed for both hydrated and powder forms of evaluated calcium silicate cements.

RESULTS

The peak of tricalcium silicate and dicalcium silicate detected in all hydrated cements was smaller than that seen in their unhydrated powders. The peak of calcium hydroxide (Ca(OH)₂) in blood- and acid-exposed ProRoot MTA, CEM Cement, and Retro MTA specimens were smaller than that of specimens exposed to PBS. The peak of Ca(OH)₂ seen in Biodentine™ specimens exposed to blood was similar to that of PBS-exposed specimens. On the other hand, those exposed to acid exhibited smaller peaks of Ca(OH)₂.

CONCLUSION

Exposure to blood or acidic pH decreased Ca(OH)₂ crystalline formation in ProRoot MTA, CEM Cement and Retro MTA. However, a decrease in Ca(OH)₂ was only seen when Biodentine™ exposed to acid.

CLINICAL RELEVANCE

The formation of Ca(OH)₂ which influences the biological properties of calcium silicate cements was impaired by blood and acid exposures in ProRoot MTA, CEM Cement, and Retro MTA; however, in the case of Biodentine, only exposure to acid had this detrimental effect.

Effect of MTA and CEM on Mineralization-Associated Gene Expression in Stem Cells Derived from Apical Papilla

INTRODUCTION

This study assessed the effect of mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) cement on odontogenic differentiation and mineralization of stem cells.

METHODS AND MATERIALS

After confirmation of stemness and homogeneity of stem cells derived from apical papilla (SCAPs) using flow cytometry, the cells were exposed for 3 weeks to either osteogenic medium (OS) or CEM extract+OS (CEM+OS) or MTA extract in OS (MTA+OS) or DMEM based regular culture media (negative control). Relative expression of alkaline phosphatase (ALP), dentine sialophosphoprotein (DSPP), osteocalcin (OSC), and osterix (SP7) were measured at days 14 and 21 using RT-qPCR method. At the same time points Alizarin Red staining method was used to assess mineralization potential of SCAPS. Gene expression changes analysis were made automatically using REST® software and a P<0.05 was considered significant.

RESULTS

After 2 weeks of exposure, expression of all genes were between 3 and 52 times the expression of GADPH (all were upregulated except SP7 in the control, P<0.05). After 3 weeks, relative expressions of the genes: ALP, SP7, DSPP, and OSC were respectively 275.9, 528.3, 98.4, and 603.7 times the expression of GADPH in the control group (OS). These were respectively 17.405, 29.2, 11.8, and 6.5 in CEM+OS group, and 163.8, 119.7, 102.5, and 723.9 in MTA+OS group. All of these were confirmed as upregulated (P<0.05) except for ALP and OSC of DM+CEM group. After 2 weeks, alizarin red staining showed similar mineralized nodules in OS, MTA+OS, and CEM+OS. In third week, larger nodules were seen in MTA+OS and OS, but not in CEM+OS.

CONCLUSION

After 2 weeks, gene expressions were almost comparable in OS, CEM+OS, and MTA+OS. After 3 weeks, OS and MTA+OS upregulated genes much greater than in 2nd week. However, upregulation in CEM+OS might not increase in 3rd week compared to those in 2nd week.

Cytocompatibility of a self-adhesive gutta-percha root-filling material

Context:

A novel root-filling material based on the incorporation of ultrafine alkaline bioactive glass particles (bioactive gutta-percha, [BGP]) was developed to work without sealer.

Aim:

In the present study, the objective was to verify the in vitro biological response to this material by assessing its cytocompatibility.

Materials and Methods:

Prototypes of BGP were compared to conventional gutta-percha (GP), dense polystyrene beads as a negative control and fragments of latex as a positive control. Extracts of each material were prepared according to ISO 10993-5:2009, and human osteoblast-like cells in primary culture were exposed to all extracts for 24 h. Cell viability was assayed sequentially for three different parameters: mitochondrial activity, membrane integrity, and cell density.

Statistical Analysis Used:

Nonparametric analysis (using Kruskal–Wallis test combined with post hoc Dunn's test) was performed for comparison among groups, with significance established at 5%.

Results:

BGP reduced mitochondrial activity to 62% of control, but presented no toxicity on membrane integrity and proliferation assays. BGP effect on metabolism was dose-dependent and reduced to acceptable levels with dilution.

Conclusion:

The novel GP material presented slight dose-dependent effects on cell metabolism but did not affect cell survival.

Physico-chemical and Biological Properties of a New Portland Cement-based Root Repair Material

Could conventional endodontic treatment have an impact on oral health-related quality of life? There are still unresolved questions regarding this theme. In order to answer them, a systematic review on the available literature was undertaken to identify the methodological quality of and the risk of bias in all relevant studies. A broad search for articles was conducted, and only articles published before May 2016 were considered for review. The following portals were used: Pubmed, VHL (Medline, SciELO, Lilacs and BBO), Cochrane Library, and Web of Science. The keywords used for the search were ‘quality of life’ and ‘root canal treatment.’ Furthermore, we included MeSH synonyms, related terms and free terms. Articles written in any language were included according to the PICOS approach (population, intervention, comparison, outcome and study design). After application of these eligibility criteria, selected articles were qualified by assessing their methodological quality and potential risk of bias. The initial search identified 302 references. After excluding duplicated abstracts and analysing the titles and abstracts, 6 were selected. One study was added via manual search of the reference lists. From these, 2 were eligible for quality assessment and were classified as being of high methodological quality and as having low risk of bias. Based on these studies, it can be concluded that conventional endodontic treatment improves oral health-related quality of life. However, these results should be interpreted with caution, due to the lack of important methodological details in the included studies. Additional investigations are warranted to provide more evidence on this subject.

Evaluation of C. Albicans and S. Mutans adherence on different provisional crown materials

PURPOSE

Bacterial adhesion on provisional crown materials retained for a long time can influence the duration for which permanent prosthetic restorations can be healthily worn in the oral cavity. The aim of this study was to compare seven different commonly used provisional crown materials with regard to Streptococcus mutans and Candida albicans surface adhesion.

MATERIALS AND METHODS

For each group, twenty specimens of the provisional fixed prosthodontic materials TemDent (Schütz), Imıdent (Imıcryl), Tab 2000 (Kerr), Structur Premium (Voco), Systemp (Ivoclar Vivadent), Acrytemp (Zhermack), and Takilon-BBF (Takilon) were prepared (diameter, 10.0 mm; height, 2.0 mm). Surface roughness was assessed by atomic force microscopy. Each group was then divided into 2 subgroups (n=10) according to the microbial suspensions used: S. mutans and C. albicans. The specimens were incubated at 37℃ with S. mutans or C. albicans for seven days. Bacterial adherence on surfaces was assessed using the 2,3-bis[2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT) assay.

RESULTS

S. mutans showed maximum adhesion to Structur, followed by Systemp, Acrytemp, Takilon, Tab 2000, Imident, and TemDent (P<.05). The highest vital C. albicans adhesion was noted on Takilon, followed by Imident and Tab 2000; the lowest adhesion was noted on Systemp (P<.05).

CONCLUSION

The materials showed significant differences in the degree of bacterial adhesion. C. albicans showed higher surface adhesion than S. mutans on provisional crown and fixed partial denture denture materials.

BiodentineTM is cytocompatible with human primary osteoblasts

Calcium silicate-based materials have been widely studied due to their resemblance to, and similar applicability of, mineral trioxide aggregate (MTA). Among these, Biodentine™ (BD) was specifically designed as a "dentin replacement" material for applications such as root perforations, apexification, treatment of resorptive lesions, and as a retrograde filling material. The present study aimed to assess the in vitro response of human primary osteoblasts to BD using MTA AngelusTM as a reference material, by simultaneously analyzing three different cell viability parameters, namely mitochondrial activity, membrane integrity, and cell density. BD and MTA extracts were prepared by incubation on culture media for 24 h or 42 days after mixing. Primary human osteoblasts were exposed to extracts for 24 h, at 37oC with 5% CO2, and cell viability was evaluated by the XTT, NRU, and CVDE assays. Both materials induced cell viability levels higher than 70% when extracted for 24 h. However, when cells were exposed to extracts with increased conditioning times, MTA presented significant cytotoxic effects (p < 0.05) in comparison to the control and MTA at 24 h. After 42 days, the XTT assay identified a significant reduction in cell viability by BD when compared to the control (p<0.05), despite the fact that levels above the 70% viability cutoff were attained for biocompatible materials. It can be concluded that BD is cytocompatible with human primary osteoblasts, indicating its adequacy in direct contact with bone tissues.

Cytotoxicity Evaluation of Two Bis-Acryl Composite Resins Using Human Gingival Fibroblasts

Bis-acryl resins are used for temporary dental restorations and have shown advantages over other materials. The aim of this work was to evaluate the in vitro cytotoxicity of two bis-acryl composite resins (Protemp 4 and Luxatemp Star), obtained at 1, 7 and 40 days after mixing the resin components, using a standardized assay employing human primary cells closely related to oral tissues. Human gingival fibroblast cell cultures were exposed for 24 h to either bis-acryl composite resins, polystyrene beads (negative control) and latex (positive control) extracts obtained after incubation by the different periods, at 37 °C under 5% CO2. Cell viability was evaluated using a multiparametric procedure involving sequential assessment (using the same cells) of mitochondrial activity (XTT assay), membrane integrity (neutral red test) and total cell density (crystal violet dye exclusion test). The cells exposed to the resin extracts showed cell viability indexes exceeding 75% after 24 h. Even when cells were exposed to extracts prepared with longer conditioning times, the bis-acryl composite resins showed no significant cytotoxic effects (p>0.05), compared to the control group or in relation to the first 24 h of contact with the products. There were no differences among the results obtained for the bis-acryl composite resins evaluated 24 h, 7 days and 40 days after mixing. It may be concluded that the bis-acryl resins Protemp 4 and Luxatemp Star were cytocompatible with human gingival fibroblasts, suggesting that both materials are suitable for use in contact with human tissues.

Cytocompatibility of calcium silicate-based sealers in a three-dimensional cell culture model

OBJECTIVES

The aim of the present study was to evaluate cytotoxic effects and cytokine production of calcium silicate-based sealers (EndoSeal, EndoSequence BC Sealer, and MTA Fillapex) using an in vitro root canal filling model and three-dimensional (3D) cell culture. AH Plus as a reference was compared to contemporary calcium silicate cements regarding cell viability and cytokine production.

MATERIAL AND METHODS

Root canals of 30 human maxillary incisors were prepared using a single-file reciprocating technique. The samples were randomly distributed and canals filled with either AH Plus, EndoSeal, EndoSequence BC Sealer, and MTA Fillapex (n = 6). In the negative control group, the root canal remained unfilled. Sealers were placed into the canals along with a gutta-percha cone placed to working length. Balb/c 3T3 fibroblasts, cultured in a type I collagen 3D scaffold, were exposed to filling material and the respective root apex for 24 h. Cytocompatibility of the materials was evaluated using the methyl-thiazoldiphenyl-tetrazolium (MTT) assay. The production of IL-1β, IL-6, and IL-8 was analyzed using enzyme-linked immunosorbent assay (ELISA). One-way analysis of variance was performed, and when the F-ratios were significant, data were compared by Duncan's multiple-range test. The alpha-type error was set at 0.05.

RESULTS

EndoSeal, Endosequence BC Sealer and AH Plus showed cell viability that was similar to the negative control group (P > 0.05), while MTA Fillapex sealer was cytotoxic (P < 0.05). Varying production of IL-1β, IL-6, and IL-8 was detected in all samples.

CONCLUSIONS

In an in vitro root canal filling model with 3D cell culture, AH Plus, EndoSeal, and EndoSequence BC Sealer were cytocompatible.

CLINICAL RELEVANCE

These results may suggest that AH Plus, EndoSeal and EndoSequence BC Sealer may achieve better biological response when compared to MTA Fillapex.

Cytocompatibility and biocompatibility of nanostructured carbonated hydroxyapatite spheres for bone repair

Objective

The aim of this study was to investigate the in vitro and in vivo biological responses to nanostructured carbonated hydroxyapatite/calcium alginate (CHA) microspheres used for alveolar bone repair, compared to sintered hydroxyapatite (HA).

Material and Methods

The maxillary central incisors of 45 Wistar rats were extracted, and the dental sockets were filled with HA, CHA, and blood clot (control group) (n=5/period/group). After 7, 21 and 42 days, the samples of bone with the biomaterials were obtained for histological and histomorphometric analysis, and the plasma levels of RANKL and OPG were determined via immunoassay. Statistical analysis was performed by Two-Way ANOVA with post-hoc Tukey test at 95% level of significance.

Results

The CHA and HA microspheres were cytocompatible with both human and murine cells on an in vitro assay. Histological analysis showed the time-dependent increase of newly formed bone in control group characterized by an intense osteoblast activity. In HA and CHA groups, the presence of a slight granulation reaction around the spheres was observed after seven days, which was reduced by the 42^nd day. A considerable amount of newly formed bone was observed surrounding the CHA spheres and the biomaterials particles at 42-day time point compared with HA. Histomorphometric analysis showed a significant increase of newly formed bone in CHA group compared with HA after 21 and 42 days from surgery, moreover, CHA showed almost 2-fold greater biosorption than HA at 42 days (two-way ANOVA, p<0.05) indicating greater biosorption. An increase in the RANKL/OPG ratio was observed in the CHA group on the 7^th day.

Conclusion

CHA spheres were osteoconductive and presented earlier biosorption, inducing early increases in the levels of proteins involved in resorption.

Assessment of the biocompatibility of mineral trioxide aggregate, bioaggregate, and biodentine in the subcutaneous tissue of rats

OBJECTIVE

The objective of this study was to evaluate the tissue inflammation caused by three endodontic repair materials.

MATERIALS AND METHODS

The materials included micro mega-mineral trioxide aggregate (MM-MTA), bioaggregate (BA), and biodentine (BD), which were implanted into the subcutaneous tissue of rats. The tissue samples for histological examination were prepared. The infiltration of lymphocytes and macrophages into the tissue was examined to assess the inflammatory response.

RESULTS

Lymphocyte infiltration: A significant increase was detected in the MM-MTA and BA groups on the 7th and 14th days as compared with the control (7th day P=0.0001, 14th day P=0.0176). There was no difference between the groups on the 45th day (P=0.1730). Lymphocyte infiltration had decreased over time in all groups. Macrophage infiltration: There was a significant increase by the 7th day in the test groups as compared to the control group (P=0.007). However, there was no difference between the experimental groups on the 14th (P=0.2708) and 45th (P=0.1291) days.

CONCLUSION

While MM-MTA and BA showed a similar biocompatibility, BD was more biocompatible than MM-MTA and BA in the 1 st week of the experiment. However, there was no difference between the materials at the end of the 45th day. MM-MTA, BA, and BD can be considered suitable endodontic repair materials.

Determination of trace elements in rat organs implanted with endodontic repair materials by ICP-MS

To investigate the levels of seven elements using an inductively coupled plasma-mass spectrometry (ICP-MS) method in rat organs after the implantation of Micro Mega Mineral Trioxide Aggregate (MM-MTA), Bioaggregate (BA) and Biodentine (BD) materials. MM-MTA, BA and BD were implanted into the subcutaneous tissue of 15 Wistar albino rats; three control animals had no operation. After 45 days, the rats were sacrificed and their brains, kidneys and livers were removed. The ICP-MS analysis was used to determine trace elements. Data were analysed using the Kruskal-Wallis and Connover post hoc tests. There was no significant difference between the control groups and the MM-MTA, BA and BD groups according to the concentration of aluminum, calcium, arsenic and lead in the rats' organs. Beryllium was not detected in all tissue samples. Chromium levels of these materials were higher than the control group in brain and kidney samples (P = 0.038 and P = 0.037); magnesium levels were higher than the control group in kidney and liver samples (P = 0.030 and P = 0.008). MM-MTA, BA and BD were nontoxic according to trace element levels in brain, kidney and liver samples of rats. Further investigation is required to understand the systemic effects of these materials.

Evaluation of cytocompatibility of calcium silicate-based endodontic sealers and their effects on the biological responses of mesenchymal dental stem cells

AIM

To investigate in vitro the cytocompatibility of the calcium silicate-containing endodontic sealers MTA Fillapex and TotalFill BC Sealer on human periodontal ligament stem cells (hPDLSCs) by assaying their biological responses and compare them with that observed when using an epoxy resin-based sealer (AH Plus).

METHODOLOGY

Specimens from the three different endodontic sealers were eluated with culture medium for 24 h. The cytotoxicity of these eluates was evaluated using the MTT assay. In addition, an in vitro scratch wound healing model was used to determine their effects on cell migration. Cell adhesion to collagen type I after treatment with the different sealer eluates was also measured, whereas cytotoxicity was determined using the DNA-specific fluorochrome Hoechst 33342. Finally, to assess cell morphology and attachment to the different sealers, hPDLSCs were directly seeded onto the material surfaces and analysed by scanning electron microscopy (SEM). One-way analysis of variance (anova) followed by a Bonferroni post-test were performed (P < 0.05).

RESULTS

hPDLSCs exposed to different dilutions of TotalFill BC Sealer eluates had significantly higher cell proliferation compared with that observed when cells were treated with AH Plus and MTA Fillapex eluates (P < 0.001). In addition, TotalFill eluates were associated with significantly increased cell adhesion to collagen type I and migration of hPDLSCs in a concentration-dependent manner than displayed after treatment with MTA Fillapex or AH Plus eluates (P < 0.001). Moreover, TotalFill BC Sealer-induced cytotoxicity was significantly lower than observed using AH Plus and MTA Fillapex eluates (P < 0.001). Finally, SEM studies revealed suitable proliferation, cell spreading and attachment, especially when using TotalFill BC Sealer discs.

CONCLUSION

TotalFill BC Sealer exhibited a higher cytocompatibility than AH Plus and MTA Fillapex. Further investigations using in vivo animal models are required to validate the potential biological responses of TotalFill BC Sealer on hPDLSCs.

Cytotoxicity and gelatinolytic activity of a new silicon-based endodontic sealer

PURPOSE

To compare the cytotoxicity, gelatinolytic activity, and protein levels (MMP-2 and MMP-9) produced by 3T3 fibroblasts cells after stimulation with GuttaFlow 2 and AH Plus.

METHODS

3T3 fibroblasts were incubated with elutes of GuttaFlow 2 and AH Plus for 24 h. The cytotoxicity of tested materials was determined using the MTT and the LDH assay. Supernatants of cell cultures incubated with sealers were collected to determine the levels of MMP-2 and MMP-9 gelatinolytic activity by gelatin zymography. Cell lysates were used to determine MMP-2 and MMP-9 protein levels by Western Blot. Data were analyzed using ANOVA and Tukey test (P&lt;0.05).

RESULTS

AH Plus showed significantly less cell viability (mitochondrial activity of cells) than GuttaFlow 2 (P&lt;0.01). Moreover, GuttaFlow 2 was noncytotoxic, showing no statistically significant difference in LDH leakage levels compared to the control group (P&gt;0.05). Specific characterization of MMPs demonstrated that GuttaFlow 2 seemed not to affect MMP-2 levels compared with the control group, while AH Plus had elevated gelatinolytic activity and protein levels of MMP-2 as confirmed by quantitative measurements. No detectable gelatinolytic activity or protein levels of MMP-9 (92 kDa) was observed in any tested group.

CONCLUSIONS

GuttaFlow 2 did not showed cytotoxic effects and did not induce MMP-2 or MMP-9 expression.

Advances in Dental Materials through Nanotechnology: Facts, Perspectives and Toxicological Aspects

Nanotechnology is currently driving the dental materials industry to substantial growth, thus reflecting on improvements in materials available for oral prevention and treatment. The present review discusses new developments in nanotechnology applied to dentistry, focusing on the use of nanomaterials for improving the quality of oral care, the perspectives of research in this arena, and discussions on safety concerns regarding the use of dental nanomaterials. Details are provided on the cutting-edge properties (morphological, antibacterial, mechanical, fluorescence, antitumoral, and remineralization and regeneration potential) of polymeric, metallic and inorganic nano-based materials, as well as their use as nanocluster fillers, in nanocomposites, mouthwashes, medicines, and biomimetic dental materials. Nanotoxicological aspects, clinical applications, and perspectives for these nanomaterials are also discussed.

Calcium silicate-based cements: composition, properties, and clinical applications

Mineral trioxide aggregate (MTA) is a calcium silicate-based cement (CSC) commonly used in endodontic procedures involving pulpal regeneration and hard tissue repair, such as pulp capping, pulpotomy, apexogenesis, apexification, perforation repair, and root-end filling. Despite the superior laboratory and clinical performance of MTA in comparison with previous endodontic repair cements, such as Ca(OH)₂ , MTA has poor handling properties and a long setting time. New CSC have been commercially launched and marketed to overcome the limitations of MTA. The aim of the present review was to explore the available literature on new CSC products, and to give evidence-based recommendations for the clinical use of these materials. Within the limitations of the available data in the literature regarding the properties and performance of the new CSC, the newer products could be promising alternatives to MTA; however, further research is required to support this assumption.

Analysis of radiopacity, pH and cytotoxicity of a new bioceramic material

OBJECTIVE

RetroMTA® is a new hydraulic bioceramic indicated for pulp capping, perforations or root resorption repair, apexification and apical surgery. The aim of this study was to compare the radiopacity, pH variation and cytotoxicity of this material to ProRoot® MTA.

MATERIAL AND METHODS

Mixed cements were exposed to a digital x-ray along with an aluminum stepwedge for the radiopacity assay. pH values were verified after incubation period of 3, 24, 48, 72 and 168 hours. The cytotoxicity of each cement was tested on human periodontal ligament fibroblasts using a multiparametric assay. Data analysis was performed using ANOVA and Tukey'spost hoc in GraphPad Prism.

RESULTS

ProRoot® MTA had higher radiopacity than RetroMTA®(p<0.001). No significant differences were observed for the pH of the materials throughout experimental periods (p>0.05) although pH levels of both materials reduced over time. Both ProRoot® MTA and RetroMTA® allowed for significantly higher cell viability when compared with the positive control (p<0.001). No statistical difference was observed between ProRoot® MTA and RetroMTA® cytotoxicity level in all test parameters, except for the ProRoot® MTA 48-hour extract media in the NR assay (p<0.05).

CONCLUSION

The current study provides new data about the physicochemical and biological properties of Retro® MTA concerning radiopacity, pH and cytotoxic effects on human periodontal ligaments cells. Based on our findings, RetroMTA® meets the radiopacity requirements standardized by ANSI/ADA number 572, and similar pH values and biocompatibility to ProRoot® MTA. Further studies should be performed to evaluate additional properties of this new material.

Can Mineral Trioxide Aggregate and Nanoparticulate EndoSequence Root Repair Material Produce Injurious Effects to Rat Subcutaneous Tissues?

INTRODUCTION

The aim of this study was to evaluate the injurious effects of mineral trioxide Aggregate (MTA) and EndoSequence Bioceramic Root Repair Material (ERRM; Brassler USA, Savannah, GA) 7 and 30 days after their implantation into rat subcutaneous tissues.

METHODS

Twelve Wistar rats were selected for the present study. Each animal received 3 implants: one contained MTA, one contained ERRM, and one was an empty tube that served as a control. Half of the animals were killed after 7 days, and the remaining animals were killed 30 days after implantation. Histologic sections prepared from the skin specimens were stained with H&E, toluidine blue, Masson trichrome, and Congo red. The data were statistically analyzed with 1-way analysis of variance and paired t tests. The P value for significance was set at .05.

RESULTS

After 7 days, MTA produced a significantly greater inflammatory reaction that involved the deposition of amyloidlike protein and an increase in the mast cell population compared with ERRM (P < .05). After 30 days, the ERRM group exhibited significantly reduced inflammatory reactions compared to the MTA groups (P < .05). Areas of mononuclear cell aggregation, abscess formation, and necrosis were observed more frequently in the MTA group. The thickness of the fibrous capsule was significantly increased in the MTA compared with the ERRM groups (P < .05). Amyloidlike proteins were more frequently observed around the fibrous capsule and subdermal blood vessels and were more frequently deposited in the MTA than the ERRM specimens.

CONCLUSIONS

The findings of the present study suggest that both ERRM and MTA cause an injurious effect when implanted in rat subcutaneous tissues after 7 and 30 days. ERRM is significantly less injurious to tissues than MTA.