Solubility of bioceramic- and epoxy resin-based root canal sealers: A systematic review and meta-analysis

Comparative Analysis of Interfacial Adaptation and Depth Penetration of Recent HiFlow versus Regular Bioceramic Sealers in Conjunction with BC Gutta-Percha Points Using Two Different Obturation Techniques-A Preliminary Report of an Ex Vivo Study

This study aimed to assess the adaptability and penetration depth capacity of recent bioceramic systems, including regular EndoSequence (BC) versus HiFlow (BCH) sealers in the presence of BC points. A total of 54 single-rooted teeth were instrumented and obturated with either the cold or warm compaction technique (n = 9), using either BC, BCH, or AH Plus (AHP) combined with BC points. The adaptation, film thickness, and gaps/voids were evaluated by scanning electron microscopy. The sealer/dentin interface was evaluated by Raman spectroscopy, and depth penetration was evaluated by a confocal laser scanning microscope. According to the normality test, the data were statistically analyzed by ANOVA or Kruskal-Wallis and Mann-Whitney U tests at p < 0.05. BCH sealer showed the significantly thinnest film with the greatest flow (p > 0.001), with further improvement when subjected to the warm compaction technique. Moreover, it exhibited close adaptation with deep penetration into radicular dentin, forming a tag-like structure. The Raman spectra also indicated close contact with the dentin surface. The use of BC sealer with BC points exhibited homogenous, single-unit obturation, either with a cold or warm technique. Furthermore, the use of the warm compaction technique with BCH sealer achieved a gap-free interface associated with tag-like structures, which exhibit the monoblock phenomenon.

Physicochemical Changes in Root-Canal Sealers under Thermal Challenge: A Comparative Analysis of Calcium Silicate- and Epoxy-Resin-Based Sealers

INTRODUCTION

We compared the effects of heat on the physicochemical properties of recently developed calcium silicate-based sealers (CSBSs), including BioRoot Flow, BioRoot RCS, and AH Plus Bioceramic sealer, with those of the epoxy-resin-based sealer (ERBS) AH Plus.

METHODS

The flow, film thickness, setting time, and solubility of sealers were evaluated at 37 °C and 100 °C using ISO 6876/2012. Furthermore, pH and calcium ion release were evaluated at these temperatures. In addition, the mass change in sealers at a high temperature was assessed via thermogravimetric analysis. Then, the chemical composition and components of the sealers were analyzed using a scanning electron microscope and Fourier-transform infrared spectroscopy (FTIR).

RESULTS

BioRoot Flow, AH Plus Bioceramic, and AH Plus complied with ISO standards in terms of flow and film thickness, both before and after heat application. However, BioRoot RCS exhibited significantly increased film thickness at 100 °C. The setting times of all sealers were significantly reduced at 100 °C. The solubility of CSBS was >3%, exceeding the ISO 6876/2012 standard, both before and after heat exposure. Conversely, the solubility of AH Plus complied with the standard, regardless of the thermal condition. For 4 weeks, CSBS showed a significantly higher pH than AH Plus at both 37 °C and 100 °C. After heat treatment, calcium release decreased in Bioroot RCS and BioRoot Flow, while AH Plus showed no significant differences before and after treatment. However, CSBS consistently exhibited significantly higher calcium release than AH Plus at both temperatures. An FTIR analysis revealed that the chemical composition of the sealers did not change at the high temperature, whereas a thermogravimetric analysis demonstrated a >5% weight reduction in CSBS and a 0.005% weight reduction in AH Plus at 100 °C.

CONCLUSIONS

BioRoot Flow, AH Plus Bioceramic, and AH Plus possess favorable physicochemical properties, which make them suitable for application under thermal conditions. At a high temperature, BioRoot RCS did not exhibit changes in its chemical composition. However, its film thickness was increased, and pH and solubility were reduced. Therefore, caution is needed when it is applied at high temperatures, such as during the warm obturation technique.

The Effect of Chitosan Incorporation on Physico-Mechanical and Biological Characteristics of a Calcium Silicate Filling Material

OBJECTIVES

A tricalcium silicate-based cement, Biodentine™, has displayed antibiofilm activity when mixed with chitosan powder. This study aimed to assess the effect of chitosan incorporation on the physico-mechanical and biological properties of Biodentine™.

METHODS

In this study, medium molecular weight chitosan powder was incorporated into Biodentine™ in varying proportions (2.5 wt%, 5 wt%, 10 wt%, and 20 wt%). The setting time was determined using a Vicat apparatus, solubility was assessed by calculating weight variation after water immersion, radiopacity was evaluated and expressed in millimeters of aluminum, the compressive strength was evaluated using an Instron testing machine, and the microhardness was measured with a Vickers microhardness tester. In addition, surface topography of specimens was analyzed using scanning electron microscopy, and the effect of chitosan on the viability of human embryonic kidney (HEK 293) cells was measured by a colorimetric MTT assay.

RESULTS

Incorporation of 2.5 wt% and 5 wt% chitosan powder delivered an advantage by speeding up the setting time of Biodentine material. However, the incorporation of chitosan compromised all other material properties and the crystalline structure in a dose-dependent manner. The chitosan-modified material also showed significant decreases in the proliferation of the HEK 293 cells, signifying decreased biocompatibility.

SIGNIFICANCE

Chitosan incorporation into calcium silicate materials adversely affects the physical and biological properties of the material. Despite the increased antimicrobial activity of the modified material, the diminution in these properties is likely to reduce its clinical value.

Premixed calcium silicate-based root canal sealers have better biological properties than AH Plus: A systematic review and meta-analysis of in vivo animal studies and in vitro laboratory studies

Objectives

The aim was to determine whether premixed calcium silicate-based root canal sealers have better biological properties than AH Plus.

Materials and Methods

Searches of studies published up to January 2023 were performed in the PubMed/MEDLINE and EMBASE and via other methods (databases of the International Endodontic Journal, Journal of Endodontics, and gray literature). The inclusion criteria were in vivo animal and in vitro studies that analyzed the response in the dorsal subcutaneous tissue of rats, cell viability, and genotoxicity. Systematic Review Centre for Laboratory Animal Experimentation Risk of Bias (RoB) tool for in vivo studies and modified CONSORT checklist for in vitro were appraised. Meta-analysis was performed using the Stata.

Results

Fifty-two studies were included. In the RoB, in vivo studies fulfilled 20%-50% of the items and in vitro 60%-100%. The studies included in the meta-analysis demonstrated better histocompatibility with the premixed calcium silicate-based sealers at 30 days and greater cell viability with these sealers when used in undiluted extracts in experimental period of 72 h and in extracts with 1:2 and 1:4 dilution in 24 and 72 h. In contrast, no difference between materials was found concerning genotoxicity.

Conclusion

Premixed calcium silicate-based root canal sealers have better histocompatibility and are less cytotoxic than the epoxy resin-based sealer AH Plus, demonstrating favorable biological behavior.

Oxidative damage analysis and cell viability of Drosophila melanogaster exposed to three different endodontic sealers: an in vivo and ex vivo study

The aim of this work was to evaluate the toxicological action of AH Plus (AHP), Bio-C Sealer (BCS), and EndoSequence BC Sealer (ESB), using Drosophila melanogaster as the model organism performing in vivo and ex vivo analysis. D. melanogaster were exposed for 10 days to three concentrations (5 mg/ml, 10 mg/ml, and 20 mg/ml) of AHP, BCS, and ESB sealers mixed with 10 ml of standard diet. During this period, the mortality of flies was evaluated. On the 11th day, the locomotor activity test was performed and the flies were euthanized for oxidative damage analysis (reactive species and lipid peroxidation) and cell viability (resazurin reduction). For the mortality curves evaluation, the log-rank test (Mantel-Cox) was used. For the analysis of other data, a one-way analysis of variance (ANOVA) was applied, followed by Tukey's post hoc test (α  =  0.05). Regarding mortality, there were no significant differences. The locomotor activity was reduced, mainly in the two highest concentrations of AHP and BCS. Besides, reactive species generation was bigger in the AHP 20 mg/ml group. AHP induced a lipid peroxidation increase in all three concentrations tested, when compared to other sealers. Considering cell viability, the two highest concentrations of AHP reduced this parameter; while in other sealers, viability was reduced only in the highest concentration. AHP showed changes in oxidative markers that led to greater damage to the flies.

Root canal dentin wear during final irrigation in endodontic retreatment with passive ultrasonic irrigation and easy clean instruments

Context

Complementary procedures have been proposed to improve the endodontic retreatments.

Aim

The aim of this study was to evaluate, by microcomputed tomography (micro-CT), the dentin wear caused by passive ultrasonic irrigation (PUI) and easy clean (EC) instruments, when used for the final removal of filling material during endodontic retreatment.

Methods

Thirty-six mesial roots of the lower first molars were divided into four groups (n = 9), according to the final irrigation and sealer: PUI/AH Plus, EC/AH Plus, PUI/Total Fill (TF), and EC/TF. Canal volume was evaluated, both before and after the final irrigation, by micro-CT analysis. The Kruskal-Wallis test was used to compare the volumes among groups and the paired Wilcoxon test was used to compare the volume values before and after the final irrigation within each group.

Results

Both complementary cleaning procedures promoted dentin wear that was observed only when the volume was analyzed for each third of the root canal. In the apical third, both instruments showed significant wear, where the use of the EC instrument resulted in greater wear than the PUI, in teeth filled with both AH Plus and TF BC Sealers (P < 0.05).

Conclusion

Both complementary cleaning procedures promoted dentin wear and must be used cautiously.

Characterization and Assessment of Physical Properties of 3 Single Syringe Hydraulic Cement-based Sealers

INTRODUCTION

A number of sealers with different chemistries are badged as Bioceramic, implying biological activity, but have dissimilar properties, which has implications on the sealer properties and will affect the quality and outcome of root canal treatment. This study aimed to assess the physical and chemical properties of 3 hydraulic cement-based sealers, namely BC Universal sealer compared with Totalfill BC sealer and AH Plus Bioceramic.

METHODS

The microstructure and composition of the sealers were assessed using scanning electron microscopy and energy dispersive spectroscopy after setting. The crystalline phases were assessed by X-ray diffraction analysis and the leachates were tested using inductively coupled plasma. All testing was performed at 0, 7, and 28 days. The physical properties of film thickness, flow, radiopacity, and solubility were evaluated using ISO 6876:2012 standards.

RESULTS

All 3 sealers contained calcium, zirconium, and silicon. Totalfill BC had the highest calcium release at 7 and 28 days followed by AH Plus Bioceramic and BC Universal sealer. All 3 sealers adhered to the ISO standard in terms of flow and radiopacity. BC Universal sealer was slightly over the range (>50 μm) for film thickness. All sealers exceeded the solubility range set by ISO 6876:2012.

CONCLUSION

Although these hydraulic cement sealers had similar components and delivery, the properties varied significantly. The testing of material properties to confirm the suitability for clinical use is necessary.

Endodontic sealers after exposure to chlorhexidine digluconate: An assessment of physicochemical properties

OBJECTIVES

Final root canal irrigation should ideally maintain the physicochemical stability of root canal sealers. We seek to assess the effect of contact with 2% chlorhexidine digluconate (CHX) on the physicochemical properties of AH Plus, BioRoot™ RCS, and Pulp Canal Sealer (PCS).

METHODS

Mixed sealers were placed in cylindrical teflon molds and allowed to set for 1.5x the manufacturers' setting time. Half of the specimens had their free surface in contact with CHX for the first minute of their setting period. Solubility, radiopacity, surface roughness, microhardness and wettability of the sealers were assessed up to 28 days after setting. Elemental analysis of sealer surfaces and their leachates together with pH measurements were also performed. Appropriate parametric and non-parametric analysis with post hoc tests were performed (p < 0.05).

RESULTS

Exposure to CHX had no effect on solubility and radiopacity of all sealers. CHX altered the surface roughness of PCS and BioRoot RCS (p < 0.05). Contact with CHX reduced the microhardness of AH Plus and PCS (p < 0.05). AH Plus was more hydrophilic after CHX contact, whereas PCS became more hydrophobic (p < 0.05). AH Plus and PCS surfaces appeared to adsorb CHX as exhibited by chlorine peaks after contact with CHX. Sealer leachates' alkalinity was not affected. CHX increased elution of silicon and zirconium for BioRoot and zinc for PCS leachates.

SIGNIFICANCE

In our study, CHX affected sealers' physicochemical properties to various extents. Further studies are needed to confirm the obtained results by investigating various final irrigation strategies and correlating to biological properties.

Evaluation of cytotoxicity and adaptability of a novel bioceramic root canal sealer: An in vitro and scanning electron microscope study

Context

Cytotoxicity and adaptability are among the highly imperative tests that should be performed on a novel endodontic material to ensure its successful implementation in endodontic treatment.

Aims

Assess a recently introduced bioceramic root canal sealer CeramoSeal with TotalFill BC and AH plus sealers regarding the cytotoxicity and adaptability.

Materials and Methods

Five sealer discs were prepared for each sealer and their extracts were cultured in 96-well plates containing human fibroblasts for 24 h. After their incubation, MTT solution was added to each well plate using an enzyme-linked immunosorbent assay plate reader was implemented to calculate the percentage of viable cells. Thirty mandibular single-rooted premolars were prepared using the Edge Endo rotary system, teeth were divided into three groups (n = 10) based on the sealer type: Group 1 CeramoSeal, Group 2 Totalfill, and Group 3 AH plus sealer. Teeth were sectioned longitudinally and viewed under a scanning electron microscope where the region with the gaps was identified and quantified as a percentage of the root canal's overall area.

Statistical Analysis

One-way ANOVA test was used for cytotoxicity, while Kruskal-Wallis and Friedman's tests were used for adaptability.

Results

Ceramoseal statistically significantly showed the lowest viability, at high concentrations AH plus showed the highest cell viability, while at lower concentration Totalfill BC sealer showed the highest cell viability percentage. The gap percentages were statistically significantly higher in Ceramoseal group, there was no statistically significant difference between AH Plus and Totalfill groups.

Conclusions

Ceramoseal sealer exhibited the lowest viability and highest gap percentage compared to the other sealers.

Cytotoxicity and genotoxicity of bioceramic root canal sealers compared to conventional resin-based sealer

The aim of this study was to evaluate cytotoxicity and genotoxicity of calcium-silicate based sealers and comparing them with a gold standard-an epoxy-based sealant. Two experimental cell lines were used, gingival fibroblasts (hGF) and monocyte/macrophage peripheral blood cell line (SC). The cytotoxicity (XTT assay) and genotoxicity (comet assay) were evaluated both after 24-h and 48-h incubation. Additionally, after 48-h incubation, the cell apoptosis and cell cycle progression was detected. BioRoot Flow induced a significant decrease in hGF cells viability compared to the negative control groups both after 24-h (p < 0.001) and 48-h incubation (p < 0.01). In group with SC cells, after 24-h incubation significant increase in cells viability was detected for AH Plus Bioceramic Sealer in comparison to negative control (p < 0.05). BioRoot Flow and BioRoot RCS can be considered potentially genotoxic for the hGF cells after 48-h incubation (> 20% DNA damage). BioRoot Flow and BioRoot RCS, may have potential genotoxic effects and induce apoptosis in hGF cells which may irritate periapical tissues, resulting in a delayed healing. The findings of the study would be useful in selection of an appropriate sealant for root canal filling without causing cytotoxicity and genotoxicity.

Surgical Site-Released Tissue Is Potent to Generate Bone onto TCP and PCL-TCP Scaffolds In Vitro

There is evidence that surgical site tissue (SSRT) released during orthopedic surgery has a strong mesenchymal regenerative potential. Some data also suggest that this tissue may activate synthetic or natural bone substitute materials and can thus upgrade its osteopromoting properties. In this comparative in vitro study, we investigate the composition of SSRT during total hip replacement (n = 20) harvested using a surgical suction handle. In addition, the osteopromoting effect of the cells isolated from SSRT is elucidated when incubated with porous beta-tricalcium phosphate (β-TCP) or 80% medical-grade poly-ε-caprolactone (PCL)/20% TCP composite material. We identified multiple growth factors and cytokines with significantly higher levels of PDGF and VEGF in SSRT compared to peripheral blood. The overall number of MSC was 0.09 ± 0.12‱ per gram of SSRT. A three-lineage specific differentiation was possible in all cases. PCL-TCP cultures showed a higher cell density and cell viability compared to TCP after 6 weeks in vitro. Moreover, PCL-TCP cultures showed a higher osteocalcin expression but no significant differences in osteopontin and collagen I synthesis. We could demonstrate the high regenerative potential from SSRT harvested under vacuum in a PMMA filter device. The in vitro data suggest advantages in cytocompatibility for the PCL-TCP composite compared to TCP alone.

Evaluation of Cytotoxicity, Cell Attachment, and Elemental Characterization of Three Calcium Silicate-Based Sealers

We investigated three calcium silicate-based sealers with respect to their chemical characterization, cytotoxicity, and attachment to RAW264.7 cells. BioRoot RCS (BR), Bio-C Sealer (BC), and Sealer Plus BC (SPBC) were assessed using Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence spectroscopy (XRF), and energy-dispersive X-ray spectroscopy (EDX) (n = 4) for elemental characterization, and using scanning electron microscopy (SEM) to evaluate cell morphology and adhesion. Cytotoxicity was determined at different dilutions (1:1, 1:2, and 1:5) using the succinate dehydrogenase activity (MTT assay). Statistical analysis was performed for normal distribution using the Shapiro-Wilk test and for homoscedasticity using Levene's test, and one-way ANOVA, Tukey's/Dunnett's post hoc tests for cell viability and XRF (α = 0.05). Calcium silicate hydrate and calcium hydroxide were detected by FTIR in all groups. EDX detected a higher calcium content for BR and SPBC and aluminum only in the premixed sealers. XRF detected the highest calcium release in BR (p < 0.05). The surface morphology showed irregular precipitates for all the sealers. SPBC at a 1:2 dilution resulted in the lowest cell viability compared to BR (p < 0.05) and BC (p < 0.05). The calcium silicate-based sealers produced a statistically significant reduction in cellular viability at a 1:1 dilution compared to the control group (p < 0.0001). All the sealers maintained viability above 70%.

Characterisation of the Bioactivity and the Solubility of a New Root Canal Sealer

OBJECTIVES

This study aimed to analyse the effect of using phosphate buffer solution (PBS) on the solubility, pH changes, surface structure, and elemental composition of a new bioceramic Cerafill sealer compared with Endosequence sealer and AH26 resin-based sealer.

METHODS

A fresh mixture of each sealer moistened with either deionised water or PBS was subjected to a setting time test. Set discs (n = 10) were submerged in either deionised water or PBS to evaluate pH changes and solubility at 1, 7, 14, 21, and 28 days. Surface characterisation of the sealers was done before and after solubility tests using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and Fourier transform infrared (FTIR) spectroscopy analyses.

RESULTS

An analysis of variance revealed a significant delay in setting of BC-Endosequence (P < .001) with no significant difference when each sealer was moistened with deionised water or PBS (P > .05). Both bioceramic sealers exhibited highly alkaline pH (range, 9.47-10.72). When the sealer was submerged in deionised water, Endosequence exhibited significantly greater solubility, whilst Cerafill and AH26 gained weight. When the sealers were submerged in PBS, both bioceramic sealers gained more weight, with significantly greater values for Endosequence (P < .001). Hydroxyapatite formation was revealed by SEM/EDX and FTIR.

CONCLUSIONS

PBS promoted the formation of hydroxyapatite crystals that protect the bioceramic sealers from dissolving.

Endodontic Outcome of Root Canal Treatment Using Different Obturation Techniques: A Clinical Study

OBJECTIVE

To evaluate the clinical outcome of root canal treatment by obturation technique, root canal filling quality, and tooth- and patient-related variables.

METHODS

This clinical study investigated the endodontic outcome of 114 teeth treated between the years 2009 and 2012. Three different obturation methods were used: (1) adhesive obturation using the continuous wave of condensation technique with Resilon® (CWR), (2) matching-taper single-cone technique with gutta-percha and AH Plus® (SCGP), and (3) matching-taper single-cone technique with gutta-percha and GuttaFlow® (SCGF). Pre- and postoperative periapical radiographs were performed to detect the presence of endodontic lesions (PAI classification) and to assess the quality of both the obturation and the restoration. Tooth- and patient-related data were collected.

RESULTS

The overall endodontic success rate was 75.4% after a mean observation period of 6.3 years. There were no significant correlations between the type or overall quality of obturation and the treatment outcome. Teeth with preoperative lesions had the highest odds ratio (factor of 4.98) for endodontic failure. Tooth- and patient-related variables had no significant effect on endodontic outcome.

CONCLUSIONS

The preoperative periapical status of teeth requiring endodontic treatment was a substantial prognostic factor for endodontic outcome, whereas the type of obturation material or technique did not affect it.

The effects of heating on the physicochemical properties of tricalcium silicate root canal sealers

This study evaluated the effect of heating on the physicochemical properties and surface changes of tricalcium silicate sealers. Three tricalcium silicate root canal sealers (Bio-C Sealer, BioRoot-RCS, EndoSequence BC Sealer), and one epoxy resin-based sealer (AH Plus; control) were tested. The effect of heating on setting time (ST) and flowability were assessed according to ANSI/ADA 57 and ISO 6876 standards. Solubility and dimensional change (DC) of the set sealers were evaluated at 24 hours and after 30 days; the pH of the water used in the DC testing was also measured. Tests were repeated with heated sealers in an oven at 100 °C for 1 min. SEM and EDS analysis were performed. Data were analyzed using One-Way ANOVA and Tukey post-hoc tests (α=5%). Heating decreased the ST for AH Plus and EndoSequence (p<0.05). Heating reduced flowability (p<0.05) and increased pH for AH Plus (p<0.05). The solubility of Bio-C (dried specimens) was not in accordance with the ANSI/ADA standard. The solubility of EndoSequence was significantly higher (p<0.05) when it was heated and dried after 30 days. DC of Bio-C (24 h and 30 days), BioRoot-RCS (30 days) and AH Plus (24 h and 30 days) were not in accordance with the standards. SEM and EDS analysis showed significant changes in sealer microstructure after heating. In conclusion, heating decreased the ST and increased the solubility of EndoSequence BC sealer. No significant changes in flowability, DC, and pH were identified for all three tricalcium silicate sealers after heat application. However, all sealers had significant surface changes.

Retreatment of oval-shaped root canals filled with TotalFill bioceramic or AH plus sealer

This study investigated retreatment of oval canals filled with gutta-percha and different sealers using WaveOne Gold (WOG). Single oval canals were prepared to size 30, 0.04 and obturated with gutta percha and AH Plus (AHP) or TotalFill bioceramic (TFBC) sealer. After 6-month incubation, the canals were retreated with WOG Primary (25, 0.07) under simulated body temperature, and the developed load and torque were simultaneously measured. The time and regaining the apical patency were checked. Micro-computed tomography scanning was performed to calculate the remaining obturating materials. An independent t-test and chi-square test were performed at a 95% confidence level. A shorter retreatment time was needed in TFBC than in AHP (P = 0.003). However, a higher maximum apical load was reported with AHP (P = 0.000). Meanwhile, comparable maximum coronal load and maximum torque values were observed. Apical patency was regained in all TFBC roots and only 75% of the AHP samples (P = 0.217). The remaining obturating materials were comparable in TFBC (13.02 ± 8.12%) and AHP (10.11 ± 8.46%) (P = 0.398). WOG was able to remove 89.89% and 86.98% of obturating materials in TFBC and AHP, respectively. The TFBC presented lower apical loads and faster retreatment compared to AHP.

Volume and power of expansion of novel polyurethane-based sealers

INTRODUCTION

Shrinkage and lack of interfacial adaptation between endodontic sealers and root canal walls may jeopardize the root canal treatment outcome. This study aimed to evaluate the volume and power of expansion (and the relationship between the two) of three novel root canal sealers (polyurethane expandable sealer (PES), zeolite + PES (ZPES), and elastomeric polyurethane sealer (EPS)) in comparison with an epoxy-resin based sealer (AH Plus) and a calcium silicate-based sealer (EndoSequence BC).

METHODS

This study utilized 36 cylinders (30 plastic graduated cylinders for volume of expansion and 6 steel cylinders for power of expansion) (4x10mm) filled with PES, ZPES, EPS, AH Plus, EndoSequence BC, or water (n=5/group). The plastic graduated cylinders were inserted inside a customized Linear Swell Meter (LSM) apparatus to measure the percentage of volumetric expansion. The steel cylinders were placed inside an LSM apparatus mounted onto a universal testing machine to measure the maximum pressure in psi. Specimens were tested for 72 hours for both volume and power of expansion tests. Data were analyzed using Kolmogorov-Smirnov, one-way ANOVA, Post Hoc Tukey, and Pearson correlation tests (p<0.05).

RESULTS

The volume of expansion of PES, ZPES, and EPS was significantly higher than in AH Plus and EndoSequence BC (p<0.05). For the power of expansion, no significant differences were found between the root-filling materials (p>0.05). No correlation was seen between the volume and power of expansion (p>0.05).

CONCLUSION

Although polyurethane-based sealers showed a significantly higher volume of expansion compared to AH Plus and EndoSequence BC, their power of expansion did not increase significantly.

Dimensional changes of endodontic sealers-An in vitro model simulating a clinical extrusion scenario during 18 months

OBJECTIVES

To examine the dimensional changes of endodontic sealers during 18 months using three-dimensional (3D) surface scanning and subtraction radiography in a novel in vitro sealer-extrusion model.

MATERIAL AND METHODS

Fifty endodontically instrumented acrylic teeth were randomly allocated to five groups (n = 10) filled with Apexit Plus, AH Plus, BioRoot RCS, TubliSeal EWT, and gutta-percha (control). Freshly mixed sealers were intentionally extruded during obturation. All teeth were immersed in a physiologic solution for up to 18 months. Blinded 3D surface scans (resolution: ~10 μm) and digital radiographs of the teeth were obtained at baseline (immediately after obturation); and then after 1 week, and at 1, 3, and 18 months. For blinded assessment of sealer dimensional change, 3D models and radiographs were superimposed using specific software. Volumetric differences, root mean square (RMS), and area change from subtraction radiography measured at each period within each sealer group were thereafter calculated. Repeated measures analyses were done with Bonferroni adjustment for multiple comparisons; standard errors, p values, and 95% confidence intervals (CI) were reported.

RESULTS

Analyses of the volumetric data confirmed significant, progressive material loss for Apexit Plus when compared to the other investigated sealers or the control group (p ≤ 0.02). Immersion period significantly influenced the volumetric dimensional changes of Apexit Plus already after 1 month (p < 0.01). For TubliSeal EW, the effect of the immersion period on the dimensional changes was noted after immersion for 3 months (p ≤ 0.02), while for BioRoot RCS this was evident only at 18 months (p < 0.01). Same trends were noted for the RMS data, whereas progressive dimensional changes using subtraction radiography only revealed significant changes for Apexit Plus (p = 0.01).

CONCLUSIONS

The largest dimensional changes were shown by Apexit Plus, followed by Tubliseal EWT and BioRoot RCS. AH Plus remained stable throughout 18 months.

Bioceramics in Endodontics: Updates and Future Perspectives

Bioceramics, with excellent bioactivity and biocompatibility, have been widely used in dentistry, particularly in endodontics. Mineral trioxide aggregate (MTA) is the most widely used bioceramic in endodontics. Recently, many new bioceramics have been developed, showing good potential for the treatment of endodontic diseases. This paper reviews the characteristics of bioceramics and their applications in various clinical endodontic situations, including root-end filling, root canal therapy, vital pulp therapy, apexification/regenerative endodontic treatment, perforation repair, and root defect repair. Relevant literature published from 1993 to 2023 was searched by keywords in PubMed and Web of Science. Current evidence supports the predictable outcome of MTA in the treatment of endodontic diseases. Although novel bioceramics such as Biodentine, EndoSequence, and calcium-enriched mixtures have shown promising clinical outcomes, more well-controlled clinical trials are still needed to provide high-level evidence for their application in endodontics. In addition, to better tackle the clinical challenges in endodontics, efforts are needed to improve the bioactivity of bioceramics, particularly to enhance their antimicrobial activity and mechanical properties and reduce their setting time and solubility.

In vitro evaluation of the sealing ability of combined use of iRoot BP Plus and iRoot SP for root-end filling

OBJECTIVES

The aim of this in vitro study was to evaluate the sealing ability of combined application of iRoot BP Plus Root Repair Material (BP-RRM) and iRoot SP Injectable Root Canal Sealer (SP-RCS) for root-end filling.

MATERIAL AND METHODS

A total of 120 extracted human teeth were used in this study and were randomly divided into four groups. The BP-RRM+SP-RCS group included teeth retro-filled with combined use of BP-RRM and SP-RCS (n=45), and the BP-RRM group included teeth retro-filled by BP-RRM alone (n=45). Teeth without root-end preparation and filling were equally divided into positive control (n=15) and negative control (n=15). The apical sealing ability was evaluated by micro-CT analysis, dye penetrant examination, bacterial leakage test, and glucose leakage test.

RESULTS

Micro-CT analysis showed that the total void fraction of BP-RRM+SP-RCS group was significantly lower than that of BP-RRM group, particularly at the coronal 1/3 segment of the retro-filled roots. Consistently, the maximum linear depth of dye leakage in BP-RRM+SP-RCS group was less than that of BP-RRM group. Bacterial leakage test showed that the microbial leakage in BP-RRM+SP-RCS group was significantly less than that in BP-RRM group. However, no significant difference in glucose leakage between BP-RRM+SP-RCS group and BP-RRM group was observed.

CONCLUSION

Combined use of BP-RRM and SP-RCS for root-end filling promotes apical sealing in vitro.

CLINICAL RELEVANCE

Combined use of BP-RRM and SP-RCS for root-end filling exhibited better apical sealing as compared to BP-RRM alone in vitro, and this may help reducing technical sensitivity and promoting clinical efficiency during endodontic microsurgery.

Influence of relative positions of the heat carrier and lateral canal opening on gutta-percha obturation of lateral canals in a three-dimensional-printed model

Background/purpose

Effective filling of the lateral canals is of great significance in successful root canal treatment, but it is generally being challenging. This study aimed to evaluate the influence of relative positions of the heat carrier and lateral canal opening on gutta-percha obturation of lateral canals in a three-dimensional (3D)-printed model.

Materials and methods

Thermal conductivity and real-time temperature transmission of gutta-percha were investigated using laser flash and thermal infrared analyses. 3D-printed root canal models with lateral canals at 1, 3, and 5 mm from the apex were fabricated, and different relative positions of the heat carrier were tested. The obturation process was recorded on video, and the obturation depth of the lateral canals was observed using X-ray micro-computed tomography.

Results

Gutta-percha showed low thermal conductivity of 1.07 W/(m·K), and heating increased the temperature of gutta-percha above 60 °C only within 1 mm beyond the heat carrier tip. For lateral canals at 1 and 3 mm from the apex, gutta-percha penetrated further with deeper penetration of the heat carrier (P < 0.05). For 5-mm lateral canals, the heat carrier was always at apical level and the gutta-percha obturation depth was more at 2 mm apically than at 3 or 4 mm (P < 0.05).

Conclusion

Gutta-percha is a poor thermal conductor. The position of the heat carrier in relation to the lateral canal opening affects obturation depth. Only when the heat carrier reaches or passes the lateral canal opening can gutta-percha penetrate a lateral canal.

An Updated Review on Properties and Indications of Calcium Silicate-Based Cements in Endodontic Therapy

Regarding the common use of calcium silicate cements (CSCs) in root canal therapy, their position in the context of past and present dentistry agents can provide a better understanding of these materials for their further improvement. In this context, the present review article addresses a wide range of recent investigations in the field of CSC-based products and describes details of their composition, properties, and clinical applications. The need for maintaining or reconstructing tooth structure has increased in contemporary endodontic treatment approaches. This research thus discusses the attempts to create comprehensive data collection regarding calcium ion release, bond strength, alkalinizing activity and bioactivity, and the ability to stimulate the formation of hydroxyapatite as a bioactive feature of CSCs. Sealing ability is also highlighted as a predictor for apical and coronal microleakage which is crucial for the long-term prognosis of root canal treatment integrity. Other claimed properties such as radiopacity, porosity, and solubility are also investigated. Extended setting time is also mentioned as a well-known drawback of CSCs. Then, clinical applications of CSCs in vital pulp therapies such as pulpotomy, apexification, and direct pulp capping are reviewed. CSCs have shown their benefits in root perforation treatments and also as root canal sealers and end-filling materials. Nowadays, conventional endodontic treatments are replaced by regenerative therapies to save more dynamic and reliable hard and soft tissues. CSCs play a crucial role in this modern approach. This review article is an attempt to summarize the latest studies on the clinical properties of CSCs to shed light on the future generation of treatments.

Short and Long-Term Solubility, Alkalizing Effect, and Thermal Persistence of Premixed Calcium Silicate-Based Sealers: AH Plus Bioceramic Sealer vs. Total Fill BC Sealer

This study aimed to investigate the short- and long-term solubility, alkalizing potential, and suitability for warm-vertical compaction of AH Plus Bioceramic Sealer (AHBC), and Total Fill BC Sealer (TFBC) compared to the epoxy-resin sealer AH Plus (AHP). A solubility test was performed according to ISO specification 6876 and further similar to ISO requirements over a period of 1 month in distilled water (AD) and 4 months in phosphate-buffered saline (PBS). The pH of the immersion solution was determined weekly. Sealers were exposed to thermal treatment at 37, 57, 67, and 97 °C for 30 s. Furthermore, heat treatment at 97 °C was performed for 180 s to simulate inappropriate implementation of warm vertical filling techniques. Physical properties (setting time, flow, film thickness according to ISO 6876) and chemical properties (Fourier transformed infrared spectroscopy) were assessed. AHBC and TFBC were associated with significantly higher solubility than AHP over 1 month in AD and 4 months in PBS (p < 0.05). AHBC and TFBC both reached high initial alkaline pH, while TFBC was associated with a longer-lasting alkaline potential than AHBC. Initial pH of AHBC and TFBC was higher in AD than in PBS. None of the sealers were compromised by thermal treatment.

Cytocompatibility and bioactive potential of AH Plus Bioceramic Sealer: an in vitro study

Aim

To assess the cytocompatibility and bioactive potential of the new calcium silicate cement‐based sealer AH Plus Bioceramic Sealer (AHPbcs) on human periodontal ligament stem cells (hPDLSCs) compared with the epoxy resin‐based sealer AH Plus (AHP) and the calcium silicate cement‐based sealer Endosequence BC Sealer (ESbcs).

Methodology

Standardized sample discs and 1:1, 1:2 and 1:4 eluates of the tested materials were prepared. The following assays were performed: surface element distribution via SEM–EDX, cell attachment and morphology via SEM, cell viability via a MTT assay, cell migration/proliferation via a wound‐healing assay, osteo/cemento/odontogenic marker expression via RT‐qPCR and cell mineralized nodule formation via Alizarin Red S staining. HPDLSCs were isolated from extracted third molars. Comparisons were made with hPDLSCs cultured in unconditioned (negative control) or osteogenic (positive control) culture media. Statistical significance was established at p < .05.

Results

A higher peak of Ca²+ was detected from ESbcs compared with AHPbcs and AHP in SEM–EDX. Both AHPbcs and ESbcs showed significantly positive results in the cytocompatibility assays (cell viability, migration/proliferation, attachment and morphology) compared with a negative control group, whilst AHP showed significant negative results. Both AHPbcs and ESbcs exhibited an upregulation of at least one osteo/odonto/cementogenic marker compared with the negative and positive control groups. Both ESbcs and AHPbcs showed a significantly higher calcified nodule formation than the negative and positive control groups, indicative of their biomineralization potential and were also significantly higher than AHP group.

Conclusion

AH Plus Bioceramic Sealer exhibited a significantly higher cytocompatibility and bioactive potential than AH Plus and a similar cytocompatibility to that of Endosequence BC Sealer. Endosequence BC Sealer exhibited a significantly higher mineralization potential than the other tested sealers. The results from this in vitro study act as supporting evidence for the use of AH Plus Bioceramic Sealer in root canal treatment.

Assessment of Bioceramic Sealer Retreatability and Its Influence on Force and Torque Generation

This study assesses the retreatability of TotalFill bioceramic (TFBC) and AH Plus (AHP) sealers and their impact on retreatment force and torque. Twenty-six premolar teeth with single oval canals were instrumented, obturated using the matched gutta-percha cone technique with one of the tested sealers, and then temporized. After a 6-month incubation at 37 °C and 100% humidity, the canals were retreated with the XP Shaper system. During retreatment, the generated force and torque were measured. Micro-CT scanning was run before and after the retreatment procedure to analyze the remaining obturating materials in the canals. The apically directed maximum force in AHP was higher than that in TFBC. The coronally directed maximum force and the maximum torque were comparable between the groups. A higher amount of remaining obturating materials was found in the AHP compared to that in the TFBC. Based on these findings, endodontic sealer had an influence on retreatability, and the TFBC showed less remaining obturating materials and lower retreatment forces in the apical direction compared to the AHP in extracted teeth with oval canals.

A critical analysis of research methods and experimental models to study root canal fillings

Canal filling materials and techniques have been one of the most studied topics in Endodontics. A simple search using the mesh term "root canal filling" in PubMed revealed more than 11,000 articles, an impressive number that is much higher than "root canal disinfection" (5,544 articles) or even the popular "root canal preparation" (8,527 articles). The overriding importance attributed to root filling procedures is not merely intuitive. It derived from the appealing relevance given by the appearance of the white lines in common radiographs grounded on retrospective clinical data that had identified the quality of a root filling as one of the major causes of treatment failure (lack of healing). Since the publication of the Washington study, impressive efforts have been made for the release of new materials and techniques, as well as, for the development of a plethora of laboratory methods to assess the quality of root filling procedures. This narrative review aims to address and discuss the most relevant laboratory methods to assess the root canal filling. Since filling quality improvements have not translated into higher success rates, as reported in longitudinal clinical studies, more than to deliver a simple methodology-based review, this paper aims to present an in-depth critical view on the assessment of laboratory methods used to study the filling materials and techniques. Recent data indicate that the long-term dimensional stability/degradation over time of endodontic sealers plays a central role in the treatment outcome. In this context, laboratory methods should be developed focusing on predicting, at least to some degree, the long-term clinical behaviour of root canal fillings, rather than simply ranking different materials or techniques.

Cytotoxicity and biocompatibility of root canal sealers: A review on recent studies

Many types of endodontic root canal sealers have been employed for the purpose of filling voids and irregularities in root canals, as well as reducing/removing bacterial remnants/remains. Sealers are available in various formulations, and research work to find the most appropriate ones is still ongoing. Recently, many kinds of novel root canal sealers have been introduced under various commercial names. However, most sealers are known to exhibit different levels of cytotoxicity on tissues which would result in prolonged wound healing, inflammation, and bone resorption. Preferably, sealers need to have tolerable biological and physico-chemical properties along with biocompatibility. Additives promoting the biocompatibility and bioactivity of sealers are of major concern in clinical applications. The aim of this review was to compare, evaluate, and analyze comparatively the cytotoxic effects, biocompatibility, and antimicrobial properties of recently used root canal sealers. A comprehensive literature search was made to identify their properties involving biocompatibility and cytotoxicity. In general, the sealers reported in recent literature exhibited favorable biological features in comparison to conventional ones. They promoted better cell viability and biocompatibility. The incorporation of additives influences favorably the potential negative effects. However, it has been highlighted that there is a lack of well-designed long-term clinical applications, and more in vitro and in vivo research work would be helpful to confirm the sustainability of the sealers for further clinical practice.

Effect of the several epoxy resin-based sealer compositions on adhesion interface in radicular dentin after calcium hydroxide intracanal medication removal

Background

This study evaluated the effects of several epoxy resin-based sealer compositions (AHP, AH Plus; ADS, Adseal; SPL, Sealer Plus) on bond strength and intratubular dentin penetration of the endodontic obturation, in root canal previously treated with calcium hydroxide intracanal medication (CH) and removed by continuous ultrasonic irrigation (CUI).

Material and Methods

Forty-five maxillary canines were prepared up to F5 (ProTaper system), filled with CH, coronally sealed, and stored at 37ºC. After 1 week, CH was removed using 2.5% sodium hypochlorite energized by CUI. The specimens were randomly distributed in three groups (n=15) and root canal obturated, according to epoxy-based resin sealer composition (AHP, ADS or SPL). The roots were transversally sectioned in cervical, middle, and apical thirds. In each radicular third, push out bond strength using universal machine and intratubular dentin using confocal laser scanning microscopy (CLSM) and Image J Program were evaluated. Bond strength and intratubular dentin penetration were statistically evaluated by ANOVA one-way and Tukey tests and Kruskal Wallis test, respectively (α = 0.05).

Results

In middle and apical thirds, AHP showed higher bond strength values (p<0.05), and ADS and SPL were similar each other (p>0.05). All epoxy resin-based sealers presented similar intratubular dentin penetration, independently of the radicular thirds (p>0.05). Cohesive and mixed failures were predominant in the cervical thirds. In the middle and apical thirds, AHP showed more cohesive type failures, while ADS and SPL showed more adhesive-type failures.

Conclusions

AHP has the highest bond strength in middle and apical radicular thirds, after calcium hydroxide intracanal medication removal using continuous ultrasonic irrigation, although intratubular dentin infiltration being similar among epoxy resin-based sealer with several chemical composition. Key words:Continuous ultrasonic irrigation, endodontic sealers, epoxy resin-based sealers, root canal obturation.

Influence of the use of chelating agents as final irrigant on the push-out bond strength of epoxy resin-based root canal sealers: A systematic review

This systematic review (PROSPERO - CRD42020150722) was performed to answer the following question: Does the use of chelating agents affect the dislodgment resistance of epoxy resin-based root canal sealers? A search was conducted in PubMed, EMBASE, Scopus, LILACS and Web of Science, hand searching of two endodontic journals and grey literature until September 2020. Extracted data included: teeth used, sample size, root canal preparation, irrigant, chelating solution, neutralisation solution, type of resin-based sealer and obturation approach, storage method and duration, root third and slice thickness, plunger dimension and loading direction and the push-out testing parameters and values. The search retrieved a total of 2.389 studies. After analysis, 12 studies fulfilled the eligibility criteria and were included. Most of the final irrigation protocols with chelating agents had a positive impact and promoted an improvement in the dislodgment resistance of epoxy resin-based sealers to the root dentin.

Antimicrobial Activity of Calcium Silicate-Based Dental Materials: A Literature Review

Endodontic biomaterials have significantly improved dental treatment techniques in several aspects now that they can be used for vital pulp treatments, as temporary intracanal medication, in definitive fillings, in apical surgeries, and for regenerative procedures. Calcium silicate-based cement is a class of dental material that is used in endodontics in direct contact with the dental structures, connective tissue, and bone. Because the material interacts with biological tissues and stimulates biomineralization processes, its properties are of major importance. The main challenge in endodontic treatments is the elimination of biofilms that are present in the root canal system anatomical complexities, as it remains even after chemical-mechanical preparation and disinfection procedures. Thus, an additional challenge for these biomaterials is to exert antimicrobial activity while maintaining their biological properties in parallel. This article reviews the literature for studies considering the antimicrobial properties of calcium silicate-based dental biomaterials used in endodontic practice. Considering the reviewed studies, it can be affirmed that the reduced antimicrobial effect exhibited by calcium silicate-based endodontic materials clearly emphasizes that all clinical procedures prior to their use must be carefully performed. Future studies for the evaluation of these materials, and especially newly proposed materials, under poly-microbial biofilms associated with endodontic diseases will be necessary.

Cytotoxicity and genotoxicity of salicylate- and calcium silicate-based root canal sealers on primer human periodontal ligament fibroblasts

The aim of this study was to evaluate the biocompatibility of epoxy-resin-based AHPlus, salicylate-based MTA-Fillapex and calcium silicate-based iRootSP root canal sealers. Cytotoxicity was assessed by XTT test. The extracts from sealers of different setting times were serially diluted. Cell viability was calculated as the percentage of the control group (100%). The optimal concentration of each sealer was used at genotoxicity test, and micronuclei formations were detected. Statistical analyses were done by using Kruskal-Wallis and Dunn post hoc test with Bonferroni correction. AHPlus and MTA-Fillapex showed the lowest percentage of cell viability at higher concentrations (1:1, 1:2, 1:4), especially at first 12 h. iRootSP showed higher viability at all concentrations and times than AHPlus and MTA-Fillapex. At genotoxicity assay, AHPlus increased the number of micronuclei. MTA-Fillapex slightly induced micronucleus formation (not significant) and iRootSP was not increased. In conclusion, calcium silicate-based iRootSP had lowest cytotoxic and genotoxic potential and can be considered as a highly biocompatible material.