The microtubule targeting agents eribulin and paclitaxel activate similar signaling pathways and induce cell death predominantly in a caspase-independent manner

Microtubule-targeting agents (MTAs) are the most effective chemotherapeutics used in cancer therapy to date, but their clinical use is often hampered by the acquisition of resistance. Thereby, elucidation of the molecular signaling pathways activated by novel FDA-approved MTAs such as eribulin is important for future therapeutic applications. In contrast to several reports, we show here that regardless of the presence of caspase-3, clinically relevant concentrations of eribulin and the classical MTA paclitaxel predominantly induce caspase-independent cell death in MCF-7 breast carcinoma cells. On the molecular level, several key proteins involved in apoptosis such as p53, Plk1, caspase-2, and Bim as well as the two MAPKs ERK and JNK were activated by both compounds to a similar extent. However, none of them proved to be important for eribulin- and paclitaxel-induced cytotoxicity, as their siRNA-mediated knockdown or inactivation by small molecule inhibitors did not alter cell death rates. In contrast, knockdown of the anti-apoptotic Bcl-2 protein, which becomes heavily phosphorylated at Ser70 during MTA treatment, resulted surprisingly in a reduction of MTA-mediated cell death. This phenomenon can be most likely explained by our observation that the absence of Bcl-2 slowed down cell cycle progression resulting in fewer cells entering mitosis, thereby delaying the mitotic capability of these MTAs to induce cell death. Taken together, although eribulin and paclitaxel disturb the mitotic spindle differently, they exhibit no functional differences in downstream molecular cell death signaling in MCF-7 breast cancer cells.

Antimicrobial activity and pH measurement of calcium silicate cements versus new bioactive resin composite restorative material

Background

The purpose of this in vitro study is to compare the antimicrobial effect and pH of two calcium silicate cements Mineral trioxide aggregate high plasticity (Angelus PR, Brazil) and iRoot BP Plus (BioCeramix Inc., Vancouver, BC, Canada) and new bioactive restorative resin composite restorative material (ACTIVA, MA, Pulpdent, USA) against aerobic bacteria, strictly anaerobic bacteria and a yeast by using an agar diffusion test.

Methods

The materials were tested immediately after manipulation and were applied to the agar plates. Sodium hypochlorite (NaOCl) 5.25% was used as a positive control group. The dry filter paper acted as a negative control group for this study. The size of the inhibition zone for each material was measured after 12, 24 and 48 h. At the time of pH measurement; materials were prepared, crushed then dispersed in distilled water.

Results

The one-way Anova test revealed that iRoot BP Plus significantly showed superior antimicrobial efficacy compared to MTA-HP against the following species; Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis, Enterococcus faecium, Peptostreptococcus anaerobius and Candida albicans (P < 0.05). All of the tested materials did not show any antimicrobial effect against Porphyromonas gingivalis and Actinomyces israelii. The new bioactive resin composite material (ACTIVA) showed the least antimicrobial activity against the previously mentioned microorganisms except E. faecalis. NaOCl significantly showed the highest antimicrobial activity among the test group (P < 0.05). iRoot BP Plus was more alkaline (pH 12.1 ± 0.14/ 11.9 ± 0.25) in comparison to MTA-HP (pH 11.6 ± 0.16/ 11.2 ± 0.10) while ACTIVA was slightly acidic (pH 5.4 ± 0.09/ 6.5 ± 0.08).

Conclusions

According to the findings of this study, it was concluded that calcium silicate- based cements showed a potential antimicrobial activity mainly due to its high alkalinity. The new bioactive resin composite restorative material exhibits less antimicrobial activity due to its resinous ingredients and slightly acidic nature. Antimicrobial effect of calcium silicate cements against strictly anaerobic bacterial species is still questionable.

Retro MTA and tricalcium phosphate/retro MTA for guided tissue regeneration of periodontal dehiscence defects in a dog model: a pilot study

Objectives

Retro MTA is a fast setting Calcium silicate cement used in endodontic regeneration procedures in recent years. Beta-tricalcium phosphate (β-TCP) is another common biomaterial used for bone augmentation procedures. The present pilot study was undertaken to evaluate and compare the efficacy of Retro MTA and a mixture of Retro MTA / β-TCP for periodontal tissue regeneration.

Materials and methods

In 4 beagle dogs, periodontal dehiscence type defects were created. In each side, one dehiscence defect was left empty as a control site and three treatment modalities were randomly applied for the others: Retro MTA covered with a collagen membrane, Retro MTA + β-TCP covered with a membrane and covering the defect with a membrane without any bone augmentation. After 8 weeks Animals were sacrificed and Histomorphometric and histologic analysis were conducted.

Results

Histologic analysis showed more cementum formation for both Retro MTA+ β-TCP (3.74 ± 0.34 mm) and Retro MTA group (3.24 ± 0.56 mm) compared to control group 1 (1. 15 ± 0.45 mm) and control group 2 (0.78 ± 0.65 mm). Formation of newly formed bone and cementum in the experimental groups were significantly higher as compared to the control groups (P < 0.0001).

Conclusions

Retro MTA or Retro MTA+ β-TCP covered with a collagen membrane resulted in regeneration of periodontal tissues. However, Retro MTA+ β-TCP showed tendency towards better results than the use of Retro MTA alone.

Effects of mineral trioxide aggregate, calcium hydroxide, biodentine and Emdogain on osteogenesis, Odontogenesis, angiogenesis and cell viability of dental pulp stem cells

BACKGROUND

Vital pulp therapy preserves and maintains the integrity and the health of dental pulp tissue that has been injured by trauma, caries or restorative procedures. The enhancement of cells viability and formation of reparative dentine and new blood vessels are vital determinants of the success of direct pulp capping. Therefore, the aims of this study was to evaluate and compare the in vitro osteogenic, odontogenic and angiogenic effects of mineral trioxide aggregate (MTA), calcium hydroxide [Ca(OH)₂], Biodentine and Emdogain on dental pulp stem cells (DPSCs) and examine the effects of the tested materials on cell viability.

METHODS

DPSCs were treated with MTA, Ca(OH)₂, Biodentine or Emdogain. Untreated cells were used as control. The cell viability was measured by MTT assay on day 3. Real-Time PCR with SYBR green was used to quantify the gene expression levels of osteogenic markers (alkaline phosphatase and osteopontin), odontogenic marker (dentin sialophosphoprotein) and angiogenic factor (vascular endothelial growth factor) on day 7 and day 14.

RESULTS

All capping materials showed variable cytotoxicity against DPSCs (77% for Emdogain, 53% for MTA, 26% for Biodentine and 16% for Ca(OH)₂ compared to control (P value < 0.0001). Osteopontin (OPN) and dentin sialophosphoprotein (DSPP) gene expression was increased by all four materials. However, alkaline phosphatase (ALP) was upregulated by all materials except Emdogain. Vascular endothelial growth factor (VEGF) expression was upregulated by all four tested materials except Ca(OH)₂.

CONCLUSIONS

Our results suggest MTA, Biodentine and Emdogain exhibit similar attributes and may score better than Ca(OH)₂. Emdogain could be a promising alternative to MTA and Biodentine in enhancing pulp repair capacity following dental pulp injury. However, further future research is required to assess the clinical outcomes and compare it with the in vitro findings.

Reparative Mineralized Tissue Characterization after Direct Pulp Capping with Calcium-Silicate-Based Cements

Nowadays, the preservation of dental pulp vitality is an integral part of our daily therapies. The success of these treatments depends on the clinical situation as well as the biomaterials used. Mineral Trioxide aggregate and Biodentine^TM are commonly used as pulp capping materials. One objective of vital pulp therapy is the repair/regeneration of the pulp. In addition to the initial inflammatory status of the pulp, the nature and quality of the new mineralized tissue obtained after pulp capping directly influence the success of the treatment. In order to characterize the reparative dentin, in the current study, the chemical composition and microstructure of the dentin bridge after direct pulp capping using Biodentine™ and mineral trioxide aggregate (MTA) was studied by using Raman microspectroscopy and scanning electron microscopy, respectively. The results showed that the reparative dentin bridge observed in both groups presented dentin tubules and chemical composition similar to primary dentin. With the limitations of this study, the calcium-silicate-based cements used as pulp capping materials provide an optimal environment for pulp healing, resulting in a reparative dentin resembling on certain points of the primary dentin and the regeneration of the pulp.

Histopathological, histoenzymological, immunohistochemical and immunofluorescence analysis of tissue response to sealing materials after furcation perforation

AIM

To evaluate in vivo tissue responses after sealing furcation perforations in dog's teeth with either Biodentine™, mineral trioxide aggregate (MTA) or gutta-percha, by means of histopathological, histoenzymological, immunohistochemical and immunofluorescence analysis.

METHODOLOGY

After root canal treatment, perforations were created in the central region of the pulp chamber floor using a round diamond bur and filled with one or other of the materials. The animals were euthanized after 120 days, and the teeth (n = 30) were processed for histopathological analysis of new mineralized tissue formation and collagen fibre reinsertion, immunohistochemical analysis of osteopontin (OPN) and alkaline phosphatase (ALP) and immunofluorescence analysis for bone morphogenetic protein (BMP-2), cementum attachment protein (CAP), bone sialoprotein (BSP), osteocalcin (OCN) and cementum protein1 (CEMP1). Histoenzymology was performed for TRAP activity and osteoclast count. Data were analysed statistically (α = 0.05) using chi-square and Kruskal-Wallis tests.

RESULTS

Gutta-percha did not induce mineralized tissue formation. MTA and Biodentine^TM formed mineralized tissue in 88% and 92% of specimens, respectively, with no significant difference (P > 0.05). Gutta-percha was associated with scattered collagen fibres parallel to the perforations. Groups treated with MTA or Biodentine^TM had partial fibre reinsertion perpendicular to the newly formed mineralized tissue. All materials induced OPN and ALP expression, weakest for gutta-percha and strongest for MTA (P < 0.05). Only MTA induced BMP-2, BSP, OCN, CAP and CEMP1 expression. Osteoclast counts were similar in all groups (P = 0.97).

CONCLUSIONS

Mineral trioxide aggregate and Biodentine^TM were biocompatible, with formation of mineralized tissue and partial reinsertion of collagen fibres. In addition, the participation of several molecules by which calcium silicate-based materials induce the formation of mineralized tissue were noted, with expression of ALP and OPN mineralization markers, without interference in the number of osteoclasts. Only MTA stimulated the expression of proteins associated with the formation of a cementum-like mineralized tissue.

Mineralogical and Microstructural Characteristics of Two Dental Pulp Capping Materials

This paper aims to investigate the composition, surface, and microstructural characteristics, and bioactivity of two commercially available pulp capping materials known as TheraCal LC and BIO MTA+. The materials were prepared as cylindrical samples and assessed by X-ray diffraction (XRD) and complex thermal analysis for mineralogical characterization, and by scanning electron microscopy (SEM) coupled with energy dispersive of X-ray (EDX), Fourier-Transformed Infrared Spectroscopy (FT-IR), and atomic force microscopy (AFM) for microstructural and surface characteristics. The in vitro bioactivity was highlighted by surface mineralization throughout SEM coupled with EDX and FT-IR analysis. XRD analysis performed on both materials showed calcium silicate phases and different radiopacifying compounds. AFM measurements indicated a smoother and more homogenous surface with a lower average roughness for TheraCal LC due to the resin matrix from its composition. FT-IR analysis displayed bands for several compounds in both materials. Both materials exhibited bioactive properties showing surface mineralization after being immersed in solution similar to the human physiological environment. However, the MTA cement showed a better mineralization due to the anhydrous and hydrated phases.

The effectiveness of endodontic sealers and endodontic medicaments on the elimination of enterococcus faecalis: an in vitro study

The aim of this study was to investigate the efficacy of endodontic sealers and endodontic medicaments: Aureoseal (OGNA), MTA (DENTSPLY), calcium hydroxide (CH) (Endoidrox OGNA) and iodoformic paste (OGNA) against Enterococcus faecalis. Thirty-six Biomeraux plates (18 MH and 18 DCO) were inoculated with the experimental suspensions. The E. faecalis broth culture suspensions were prepared and adjusted to no. 0.5-0.7 McFarland standard. In each agar plate, three cavities were created, each measuring 4mm in depth and 7mm in diameter, and then completely filled with the product to be tested. To investigate the root canal sealers' antimicrobial activity, the agar diffusion method is used. The diameters of the zones of microbial inhibition were measured in millimeters around the plate. The results showed that the antimicrobial activity of Aureoseal was superior to those of MTA, iodoformic paste and calcium hydroxide for the microorganisms tested. The study confirmed the resistance of Enterococcus faecalis to endodontic sealers. Aureoseal and Calcium hydroxide showed the best results in inhibition test suggesting to employ them in clinical cases.

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.

Tricalcium silicate cements: osteogenic and angiogenic responses of human bone marrow stem cells

Tricalcium silicate cements (TSCs) are used in endodontic procedures to promote wound healing and hard tissue formation. The aim of this study was to evaluate and compare the effect of commonly used TSCs [mineral trioxide aggregate (MTA), Biodentine, and TotalFill] on cellular metabolism and osteogenic/angiogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) in vitro. We tested the null hypothesis of no difference between MTA, Biodentine, and TotalFill in stem cell responses. Cells were subjected to eluates of the tested materials for up to 14 d. Cell viability was evaluated using the 3-(4,5-dimethyl-thiazoyl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. Real-time PCR was used to determine the levels of expression of the osteogenic factors alkaline phosphatase (ALP), osteoprotegerin (OPG), osteocalcin (OC), and collagen 1A (COL1A1), and the angiogenic factors vascular endothelial growth factor A (VEGFA) and fibroblast growth factor 1 (FGF1). ELISAs were used to measure the levels of VEGFA and ALP in culture supernatants. Mineralization in vitro of hBMSCs was assessed using Alizarin Red staining. The hBMSCs tolerated exposure to TSCs well, with Biodentine showing the most favorable effect on cell viability. Expression of ALP, COL1A1, OPG, and VEGFA were differentially affected by the materials, with Biodentine and TotalFill inducing earlier changes at gene level. Increased mineralization was observed with time, after exposure to all TSCs tested, with MTA showing the greatest effect. The results revealed different responses of hBMSCs to TSCs in vitro.

Do the intracanal medicaments affect the marginal adaptation of calcium silicate-based materials to dentin?

Background/purpose

In order to prevent reinfection of the pulp canal space and dressing for regenerative purpose, the coronal seal should have a perfect marginal adaptation. Mineral trioxide aggregate (MTA) and Biodentine are among the most popular sealing materials. These are commonly used in combination with antibiotic medicaments, to ensure disinfection. Aim of the present study was to evaluate the effect of 3 different medicaments on the marginal adaptation of MTA and Biodentine to the dentin.

Materials and methods

Teeth were divided into 4 groups (n = 20) that were treated with the following medicaments; triple antibiotic paste (TAP), double antibiotic paste (DAP), a calcium hydroxide (CH) and a control group. The specimens were then assigned into two subgroups (n = 10), which received a coronal barrier of MTA or Biodentine. The specimens were scanned using an ex vivo micro-CT scanner. The data were statistically analysed using one-way ANOVA and the unpaired Student's t-test (P < 0.05).

Results

Percentage volume of external voids in the MTA group was as follows: DAP > TAP > Control > CH. In the Biodentine group, the percentage of voids was determined in the following order: TAP ≥ DAP > CH > Control. Significantly lower percentage of voids was observed in the CH-medicated specimens in the MTA group when compared to all test groups (P = 0.04).

Conclusion

The application of CH as an intracanal medicament reduced the void occurrence between the ProRoot MTA and root dentin. However, TAP and or DAP decreased the marginal adaptation in both ProRoot MTA and Biodentine.

Sealing Ability of MTA vs Portland Cement in the Repair of Furcal Perforations of Primary Molars: A Dye Extraction Leakage Model-An In Vitro Study

AIM

The purpose of this present study is to compare the ability of MTA and Portland cement to seal furcal perforations in extracted primary molars using the dye extraction leakage model.

MATERIALS AND METHODS

Sixty primary molars were selected and randomly divided into four groups after access openings and furcal perforations were created in the pulp chamber floor. Group I (n = 20) in which perforations were repaired with MTA (ProRoot MTA, MTA-Angelus), group II (n = 20) in which perforations were repaired with the Portland cement, group III (n = 10) in which perforations were left unsealed (positive control), and group IV (n = 10) without perforations (negative control). All samples were subjected to 1% of basic fuchsin dye challenge followed by dye extraction with 65 wt% of nitric acid. Samples were analyzed using the automatic microplate spectrophotometer 545 nm and the readings were statistically analyzed.

RESULTS

There was no statistically significant difference in the microleakage between MTA and Portland cement repair groups.

CONCLUSION

Portland cement provides an effective seal for primary teeth furcal perforations and can be considered a more economic substitute for MTA as a repair material enhancing the prognosis of perforated primary teeth that would otherwise be extracted.

HOW TO CITE THIS ARTICLE

Reddy NV, Srujana P, et al. Sealing Ability of MTA vs Portland Cement in the Repair of Furcal Perforations of Primary Molars: A Dye Extraction Leakage Model-An In Vitro Study. Int J Clin Pediatr Dent 2019;12(2):83-87.

Direct pulp capping versus pulpotomy with MTA for carious primary molars: a randomised clinical trial

AIM

Aim of this randomised clinical trial was to compare the outcome of direct pulp capping (DPC) versus pulpotomy, both with MTA, for carious primary molars.

METHODS

Healthy, cooperative children aged 3-9 years with at least one deep carious primary molar requiring vital pulp therapy were included. Data on the primary outcome (all-cause failure) and secondary outcomes (clinical or radiographic failure) were collected blindly semi-annually for a minimum of 1 year up to 3 years and analysed with survival analysis and generalised linear regression at alpha = 5%.

RESULTS

A total of 74 children were randomly allocated on 1:1 basis to DPC (35 children; 40 teeth) or pulpotomy (39 children; 57 teeth). Survival from all-cause failure was 79.7% [95% confidence interval (CI) 69.3-86.9%] at 12 months and 66.0% (95% CI 53.4-76.0%) at 24 months which remained stable up to 36 months, with no differences between groups (P > 0.05). No significant difference was found in the survival rate of the two groups for all-cause [hazard ratio (HR) = 0.95; 95% CI 0.45-2.01; P = 0.88], clinical (HR = 0.74; 95% CI 0.0.19-2.92; P = 0.66), or radiographic failure (HR = 0.80; 95% CI 0.0.36-1.82; P = 0.60) throughout the 3-year follow-up. Regression analysis indicated that needing a second attempt for haemorrhage control was associated with higher clinical failure rate. All-case failure was significantly different for class II versus occlusal cavities and in the latter cavities pulpotomy performed better (P < 0.001).

CONCLUSION

The results of the current trial indicate that both DPC and pulpotomy can be reliable options for the treatment of deep carious primary molars in cooperative children, in carefully selected cases.

Fracture resistance of simulated immature teeth treated with a regenerative endodontic protocol

This study aims to evaluate fracture resistance of simulated immature teeth after treatment with regenerative endodontic procedure (REP) using tricalcium silicate cements (TSCs) as cervical plugs. Bovine incisors were sectioned to standard crown/root ratio. Pulp tissue was removed and canals were enlarged to a standardized diameter. Teeth were then treated with a REP protocol consisting of NaOCl and EDTA irrigation, intracanal medication with triple-antibiotic paste for 14 days followed by a TSC cervical seal and composite restoration. Teeth were divided into groups according to the material used; Mineral-Trioxide-Aggregate (MTA), Biodentine, TotalFill. Teeth filled with guttapercha (GP) and intact teeth served as controls. All teeth subjected to an increasing compressive force (rate of 0.05 mm/s at a 45° angle to the long axis of the tooth) until fracture. All treated teeth exhibited significantly lower resistance to fracture compared to the intact teeth but no difference was found between the TSC groups (Kruskal-Wallis, Dunn’s multiple comparison, p < .05). TSCs applied at the cervical area of simulated immature teeth treated with REP did not reinforce fracture resistance.

5'-Methylthioadenosine and Cancer: old molecules, new understanding

While the metabolic changes in cancer tissues were first observed by Warburg Otto almost a century ago, altered metabolism has recently returned as a focus of cancer research. 5'-Methylthioadenosine (MTA) is a naturally occurring sulfur-containing nucleoside found in numerous species. While MTA was first isolated several decades ago, a lack of sensitive and specific analytical methodologies designed for its direct quantification has hampered the study of its physiological and pathophysiological features. Many studies indicate that MTA suppresses tumors by inhibiting tumor cell proliferation, invasion, and the induction of apoptosis while controlling the inflammatory micro-environments of tumor tissue. In this review, we assessed the effects of MTA and of related materials on the growth and functions of normal and malignant cells.

Comparative Evaluation of Tissue Response of MTA and Portland Cement with Three Radiopacifying Agents: An Animal Study

AIM

This study compared the tissue reaction of 80 wt% of White Portland cement (WPC) mixed with 20 wt% of three radiopacifying agents: Bismuth oxide/Iodoform/Zirconium oxide with MTA in rat subcutaneous connective tissue.

MATERIALS AND METHODS

The study was performed in 18 albino rats by implanting the WPC mixed with radiopacifying agents loaded in a polyethylene tube. Empty tubes were used as a control. At the end of 7, 30 and 60 days excisional biopsy of the implant along with surrounding tissues was done and sent for histological examination.

RESULTS

In the 7 days experimental period there was no significant difference between groups in terms of the tissue response. In 30 and 60 days period significant difference was seen between the control (empty tube) and the other groups. But there was no significant difference between WPC mixed with radiopacifiers BiO/Iodoform/ZrO₂and MTA.

CONCLUSION

The tissue reaction of the tested materials, White Portland cement (WPC) + Bismuth oxide, WPC + Iodoform, and WPC + Zirconium dioxide were similar to MTA (Pro Root MTA) in all experimental periods 7 days, 30 days and 60 days.

Synthesis of a Ca3 SiO5 -Ca2 SiO4 -Ca3 Al2 O6 cement system with rapid setting capacity by spray-pyrolysis coupled with sol-gel method

A modified mineral-trioxide-aggregate (mMTA) with rapid setting capacity was newly synthesized by spray-pyrolysis following a sol-gel reaction. Its faster setting capacity and initially higher compressive strength compared with Portland cement (PC) were evaluated. The precursor solution of the mMTA was prepared through condensation following hydrolysis among Ca(NO₃ )₂ ·4H₂ O, Si(OC₂ H₅ )₄ , and Al(NO₃ )₃ ·9H₂ O under nitric acid. The mMTA powder was then synthesized by spray-pyrolysis at 1500°C. The particle shape was spherical with an average particle size of 0.8 ± 0.3 μm, while PC particles were irregular and 3.9 ± 3.0 μm in size. The mMTA consisted of mostly Ca₃ SiO₅ , Ca₃ Al₂ O₆ , and partial Ca₂ SiO₄ phases, while the PC comprised mainly Ca₃ SiO₅ , Ca₂ SiO₄ , and partial Ca₃ Al₂ O₆ phases. The final setting times of mMTA and PC measured under 95% relative humidity were about 11 min and 3 h, respectively. The early stage of setting in mMTA was dominated by the rapid formation of hexagonal-plate-like Ca₃ Al₂ O₆ ·6H₂ O crystals, while that in PC was dominated by needle-like calcium-silicate-hydrate gels and columnar-shaped Ca(OH)₂ crystals. The late stage of setting in mMTA was dominated by calcium-silicate-hydrate gels and Ca(OH)₂ crystals, while that in PC was dominated by Ca₃ Al₂ O₆ ·6H₂ O crystals. The compressive strengths of mMTA and PC after 30 min of setting were 4.5 and 0.2 MPa, respectively. The results suggest that mMTA has potential to be used as a filling material for accidental pulp-exposure or pulpal floor perforation cases that require rapid setting capacity and initial good strength. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1440-1451, 2019.

The Effect of Commercially Available Endodontic Cements and Biomaterials on Osteogenic Differentiation of Dental Pulp Pluripotent-Like Stem Cells

The aim of this study is to compare the osteogenic differentiation capacity of the dental pulp pluripotent-like stem cells (DPPSCs) using conditional media pretreated with ProRoot-MTA, Biodentine (BD) or the newly manufactured pure Portland cement Med-PZ (MZ). DPPSCs, isolated from human third molars, are the most relevant cell model to draw conclusions about the role of biomaterials on dental tissue regeneration. Cytotoxicity, alkaline phosphatase (ALP) activity, and calcium deposition analysis were evaluated at different differentiation time points. Gene expression of key osteogenic markers (RUNX2, Collagen I and Osteocalcin) was determined by qRT-PCR analysis. The osteogenic capacity of cells cultured in conditioned media prepared from MZ or MTA cements was comparable. BD conditioned media supported cell proliferation but failed to induce osteogenesis. Relative to controls and other cements, high osteogenic gene expression was observed in cultures pre-treated with the novel endodontic cement MZ. In conclusion, the in vitro behavior of a MZ- endodontic cement was evaluated, showing similar enhanced cell proliferation compared to other commercially available cements but with an enhanced osteogenic capacity with prospective potential as a novel cement for endodontic treatments.

Management of deep carious lesions and pulps exposed during carious tissue removal in adults: a questionnaire study among dentists in Finland

OBJECTIVES

To find out which management methods are preferred by dentists in Finland for a deep carious lesion or a pulp exposed during carious tissue removal in adult patients.

MATERIALS AND METHODS

An electronic questionnaire consisting of 25 questions was sent to 1000 randomly sampled dentists in Finland. The response rate was 32%.

RESULTS

Less invasive excavation strategies (stepwise or selective removal) were preferred by 64% for an asymptomatic deep lesion, while 34% chose nonselective removal to hard dentine. In the presence of an asymptomatic pulpal exposure, vital pulp therapy was preferred, as 71% of the respondents chose direct pulp capping (DPC) or partial pulpotomy, compared to root canal treatment (26%). Mineral trioxide aggregate (MTA) and calcium hydroxide-based materials were both chosen by 40% for vital pulp therapy. In the management of a deep carious lesion, less invasive excavation strategies were significantly associated with having clinical guidelines vs. no guidelines at the practice [odds ratio (OR) 3.5, confidence interval (CI) 1.4-9.0]. MTA was favored over other DPC materials significantly more often by those who had attended continuing education courses during the last 3 years (OR 2.8, CI 1.2-6.5).

CONCLUSIONS

Less invasive management strategies have been adopted into clinical practice by the majority of dentists in Finland. There is a need to encourage the use of MTA in the case of a pulpal exposure.

CLINICAL RELEVANCE

The results of this study can be utilized in continuing education, to raise awareness of management strategies supported by present scientific evidence.

Design Variability of the Push-out Bond Test in Endodontic Research: A Systematic Review

INTRODUCTION

There is limited literature on the impact of testing variables on the push-out bond test (POBT). This review identified designs of the POBT used in the endodontic literature and aimed to determine which experimental variables may influence the push-out bond strength (POBS).

METHODS

A systematic review based on PRISMA guidelines was performed by searching the PubMed, SCOPUS, and Cochrane library databases using terms including push-out and dislocation resistance and descriptions of endodontic materials. Test variables assessed included method of root preparation, timing of sectioning compared with filling, thickness, diameter and taper of sections, and plunger size and velocity. The POBS of 3 common materials (gutta-percha and AH Plus, mineral trioxide aggregate, and Biodentine) were collected from investigations, and a comparison was attempted.

RESULTS

One hundred thirty-three studies assessed the POBS of root-filling materials, 68 assessed root repair cements/root-end filling materials, and 16 assessed orifice barrier materials other than mineral trioxide aggregate. There was significant variation in all of the assessed variables, resulting in a large range of reported values for the POBS of the various materials. Because of this heterogeneity in study design, no further statistical analysis of the impact of the test variables on POBS was possible.

CONCLUSIONS

There was considerable variation in the POBT design used in endodontic research. Greater standardization is required for future research as well as accurate reporting for all test variables to assess the impact of specific design variables on POBS.

Cytokine expression in response to root repair agents

AIM

To evaluate the expression of TNF-α, IL-6, IFN-γ, TGF-β, IL-4, IL-10, RANKL, RANK and OPG on mouse calvarial bone treated with MTA, Geristore^® and Emdogain^® .

METHODOLOGY

Bone wounds were made on the heads of C57BL/6 mice, breaking the periosteum and the cortical surface of the calvaria. Each repair agent was inserted into sectioned Eppendorf microtubes and placed on the bone wound, and soft tissues were sutured. At 14 and 21 days, animals were sacrificed and the treated region was dissected. The calvaria bone was removed, and RNA was extracted. mRNA expression of the aforementioned cytokines was assessed using real-time PCR. Data were analysed by nonparametric methods, including the Mann-Whitney and Kruskal-Wallis tests (P < 0.05).

RESULTS

Following treatment with Emdogain^® and MTA, mRNA expression of RANKL, RANK and OPG increased significantly (P < 0.05) between days 14 to 21. Geristore^® did not alter the basal expression of these mediators during the same period of evaluation. Whilst treatment with Emdogain^® did cause a significant increase in TNF-α mRNA expression between days 14 and 21 (P < 0.05), treatment with MTA did not alter the basal expression of this cytokine at either experimental time point. However, TNF-α mRNA expression was down-regulated significantly at day 21 (P < 0.05) when Geristore^® was applied. A significant increase in the mRNA expression of IL-6, TGF-β, IL-10, IL-4 and IFN-γ was observed with Emdogain^® and MTA treatment between days 14 to 21, whereas Geristore^® reduced significantly the expression of IL-6, TGF-β and IL-4 (P < 0.05).

CONCLUSION

The clinical indication of these repair agents depends on the root resorption diagnosis. Whilst MTA and Emdogain^® induce a pro- and anti-inflammatory response early and late, respectively, Geristore^® was not associated with an inflammatory reaction when compared with both repair agents.

Direct pulp capping in primary molars using a resin-modified Portland cement-based material (TheraCal) compared to MTA with 12-month follow-up: a randomised clinical trial

AIM

This study was to compare the success of resin-modified Portland cement-based material (TheraCal) with MTA in direct pulp capping (DPC) of primary molars.

METHODS

Symmetrical bilateral primary molars (92) from 46 healthy subjects aged 5-7 years were included in this split-mouth randomised clinical trial. DPC for small non-contaminated pulp exposures using either TheraCal or MTA were randomly performed in symmetrical molars. Thereafter, teeth were restored with amalgam. Clinical and radiographic evaluations were performed at 6 and 12 month follow-ups. Data were analysed using Chi square test at a significance level of 0.05.

RESULTS

At the final follow-up session 74 teeth were available. After 12 months, the overall success rates for MTA and TheraCal were 94.5 and 91.8%, respectively. The difference between outcomes of the two groups was not statistically significant (P > 0.05).

CONCLUSION

Within the limitations of the current study, radiographic and clinical findings revealed that TheraCal exhibited a comparable outcome to MTA in DPC of primary molars after 12 months.

Bioactive endodontic materials for everyday use: a review

Bioceramic materials are at the forefront of modern dentistry. Bioactive bioceramic endodontic materials promote pulpal and periapical tissue healing and are easy to use. Dentists can choose among many endodontic materials, depending on their needs. This article highlights the major differences among commercially available bioactive tricalcium silicate bioceramics, commonly known as mineral trioxide aggregate materials, to enable dentists to make appropriate decisions in the selection of these materials.

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.

Biocompatibility Investigation of New Endodontic Materials Based on Nanosynthesized Calcium Silicates Combined with Different Radiopacifiers

INTRODUCTION

The aim of this article was to analyze biocompatibility and bioactivity of new endodontic materials on the basis of nanosynthesized calcium silicates (ALBO-MPCA₁ and ALBO-MPCA₂) combined with different radiopacifiers in comparison with MTA⁺.

METHODS

Morphology of the samples was studied by scanning electron microscopy, and the pH and ion release analysis were also assessed. Biocompatibility of materials' eluates (24-hour, 7-day, and 21-day) was conducted by using MTT test. Twelve New Zealand white rabbits were used for intraosseous implantation. Four calvarial defects per animal were created and filled with freshly prepared investigated materials.

RESULTS

Samples mostly consisted of agglomerates built up from nanoparticles, preferably spherical and rod-like. There was no significant difference among pH values of materials' eluates after 24 hours (P > .05). The amount of calcium and aluminum ion release decreased, whereas the amount of magnesium and bismuth (ALBO-MPCA₁, MTA⁺) and barium (ALBO-MPCA₂) increased during 21-day period. The metabolic activity of cells increased after the extraction time, except in case of undiluted elutes of ALBO-MPCA₂ and ALBO-MPCA₁ (21-day). Histologic analysis of the samples revealed newly formed bone tissue with moderate inflammation for all investigated materials, which subsided during 90-day period to mild. Both MTA⁺ and ALBO-MPCA₁ were in direct contact with the newly formed bone tissue. After 90 days, statistically significant difference in hard tissue formation was observed in comparison of MTA⁺ and ALBO-MPCA₁ with control group (P < .05).

CONCLUSIONS

Experimental materials ALBO-MPCA₁ and ALBO-MPCA₂ possess both biocompatibility and bioactivity. Because ALBO-MPCA₁ provokes favorable biological response, it is especially good candidate for further clinical investigations.