Comparison of antimicrobial activity of traditional and new developed root sealers against pathogens related root canal

A Literature Review of the Effect of Heat on the Physical-Chemical Properties of Calcium Silicate-Based Sealers

INTRODUCTION

Recently, calcium silicate-based sealers (CSSs) have gained popularity in endodontic practice due to their biocompatibility and antimicrobial properties. They are considered viable alternatives to epoxy resin-based sealers. With the increased use of CSSs and warm vertical compaction techniques in root canal treatment, evaluating the impact of heat on CSSs properties is essential, therefore this review aimed to present a qualitative synthesis of available in vitro studies assessing the impact of heat on the physical-chemical properties of CSSs.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis 2020 guidelines, a systematic advanced electronic search was performed in Scopus, Embase, Medline (via PubMed), Web of Science, and Cochrane databases in November 2023 and updated in April 2024. In vitro studies that evaluated the physical-chemical properties of CSSs were eligible. PRILE 2021 guidelines were used for the assessment of the risk of bias-included studies.

RESULTS

The search identified a total of 6421 preliminary results and 10 studies were included for qualitative assessment. Eleven different physiochemical properties were assessed by the included studies. Setting time and flow were the most evaluated property among the studies. A qualitative synthesis of the evidence on each property is presented.

CONCLUSIONS

Based on the in vitro studies assessed in the present systematic review, results reveal that exposing CSSs to heat can accelerate their setting time, reduce their flow, and increase their film thickness. Concerns persist regarding solubility, viscosity, radiopacity, dimensional change, microhardness, porosity, and compressive strength, requiring further research. Certain CSSs, such as MTA Fillapex and Endosequence BC sealer HiFlow, show minimal changes under heat, making them potential candidates for warm filling techniques.

Marginal Adaptation of BioRoot RCS, MTA-Fillapex, EpoxySeal, and Sealapex to Radicular Dentin: An In Vitro Study

Introduction The primary goal of endodontic therapy is to achieve a three-dimensional filling of the root canal. The sealer plays a crucial role in filling the residual gaps between the gutta-percha and the canal wall, which prevents fluids and bacteria from entering the canal and causing complications. This study evaluates and compares the sealing ability of four root canal sealers to the root dentin. Methods and materials In this study, forty single-rooted mandibular premolar teeth with fully-formed apices were collected. The teeth were decoronated and instrumented. Later, the teeth were randomly divided into four groups, each comprising ten specimens, based on the sealer used for obturation. The first group was obturated with BioRoot RCS (Septodont, Septodont Holding, Paris, France), the second group with MTA-Fillapex (Angelus, Angelus Indústria de Produtos Odontológicos S/A, Brazil), the third group with EpoxySeal (Safe Endo, SafeEndo Dental India Pvt. Ltd., Gujarat, India), and the fourth group with Sealapex (Kerr, Kerr Corporation, Brea, CA). Following obturation, the teeth were sectioned vertically using a diamond disc, and the marginal adaptation of these sealers to the root dentin was assessed using scanning electron microscopy (SEM). The values were then statistically analyzed. Results EpoxySeal showed the maximum amount of marginal adaptation (5.22±0.47), followed by BioRoot RCS (5.48±0.58) and MTA-Fillapex (8.24±0.74), and the least amount of marginal adaptation was shown by Sealapex (11.64±1.35). Based on the analysis of variance (ANOVA), a statistically significant difference (p≤0.001) was observed. According to Tukey's post hoc test, the mean difference between all groups showed statistical significance (p≤0.05) except between BioRoot RCS and EpoxySeal. Conclusion Within the limitations of this in vitro study, it is concluded that EpoxySeal and BioRoot RCS exhibited superior marginal adaptation to the root dentin. BioRoot RCS can be recommended as a sealer of choice owing to its additional properties, such as antimicrobial and hydrophilic affinity during setting.

Physicochemical properties of AH plus bioceramic sealer, Bio-C Sealer, and ADseal root canal sealer

BACKGROUND

The aim of this study was to evaluate the physicochemical properties of two newly introduced premixed calcium silicate-based root canal sealers (AH Plus Bioceramic Sealer and Bio-C Sealer) compared to a resin-based root canal sealer (ADseal root canal sealer).

METHODS

Solubility, pH analysis, calcium ion release, and film thickness of each sealer were evaluated following ISO guidelines. The data were examined using the two-way ANOVA test. Furthermore, X-ray diffraction (XRD) examination was performed to investigate the crystalline phase of each type of sealer. X-ray fluorescence (XRF) analysis was done for the chemical elemental analysis of each sealer.

RESULTS

The least film thickness, highest alkalinity, and highest calcium ion release were all displayed by AH Plus Bioceramic Sealer. High solubility, high alkalinity, intermediate calcium ion release, and intermediate film thickness were all displayed by Bio-C Sealer. While ADseal root canal sealer displayed the greatest film thickness, least solubility, alkalinity, and calcium ion release.

CONCLUSIONS

Both AH Plus Bioceramic Sealer and Bio-C Sealer represented adequate properties to be considered a good sealer that could be used as a potential alternative to resin-based root canal sealers.

Evaluation of push-out bond strength, dentinal tubule penetration and adhesive pattern of bio-ceramic and epoxy resin-based root canal sealers

INTRODUCTION

Root canal sealing materials play a crucial role in an endodontic procedure by forming a bond between the dentinal walls and the gutta-percha. The current study aims to analyse the dentinal tubule penetration and adhesive pattern, including the push-out bond strength of six commercially available root canal sealers.

METHODOLOGY

Eighty-four mandibular first premolars were split into seven groups (and n = 12), Group 1: Dia-Root, Group 2: One-Fil, Group 3: BioRoot RCS, Group 4: AH Plus, Group 5: CeraSeal, Group 6: iRoot SP, Group 7: GP without sealer (control). Two groups were made, one for dentinal tubule penetration and the other for push-out bond strength; the total sample size was one hundred sixty-eight. Root canal treatment was performed using a method called the crown down technique, and for obturation, the single cone technique was used. A confocal laser scanning microscope (Leica, Microsystem Heidel GmbH, Version 2.00 build 0585, Germany) was used to evaluate dentinal tubule penetration, and Universal Testing Machine was utilised to measure the push-out bond strength (Shimadzu, Japan) using a plunger size of 0.4 mm and speed of 1mm/min. Finally, the adhesive pattern of the sealers was analysed by HIROX digital microscope (KH-7700). Statistical analysis was carried out by a one-way Anova test, Dunnet's T3 test, and Chi-square test.

RESULTS

Highest dentinal tubule penetration was noticed with One-Fil (p<0.05), followed by iRoot SP, CeraSeal, AH Plus, Dia-Root also, the most negligible value was recorded for BioRoot RCS. Meanwhile, BioRoot RCS (p<0.05) demonstrated the greater value of mean push-out bond strength, followed by One-fil, iRoot SP, CeraSeal, AH Plus and Dia-Root. Regarding adhesive pattern, most of the samples were classified as type 3 and type 4 which implies greater sealing ability and better adherence to the dentinal wall. However, BioRoot RCS revealed the most type 4 (p<0.05), followed by AH Plus, One-Fil, CeraSeal and Dia-Root.

CONCLUSION

The highest dentinal tubule penetration was shown by One-Fil compared to other groups. Meanwhile, BioRoot RCS had greater push-out bond strength and more adhesive pattern than other tested materials.

Evaluation of Antibacterial Effect of New Sealer "Neoseal" and Two Commercially Used Endodontic Sealers against Enterococcus faecalis: An In Vitro Study

AIM

To evaluate the antibacterial activity of three endodontic sealing materials, Neoseal, CeraSeal, and AH Plus against Enterococcus faecalis bacteria in vitro.

MATERIALS AND METHODS

The antibacterial activity of three endodontic sealing materials including two bioceramic sealers; NeoSEALER Flo (group I), CeraSeal (group II), and one epoxy resin sealer; AH Plus (group III) was investigated against E. faecalis bacteria American Type Cell Culture Collection (ATCC) 29212 (ATCC, Rockville, Maryland, USA). Using modified direct contact test (MDCT). The endodontic sealers were tested in contact with bacterial suspension when unset (20 minutes after mixing) and after setting, assessing the antibacterial activity of aged sealers after 1, 3, 7, and 14 days. Analyzing the collected data has been done with version 25.0 of the statistical package for the social sciences (SPSS) IBM software (SPSS, Chicago, Illinois, USA). Descriptive analyses were calculated using standard deviation (SD) and mean. Shapiro-Wilk test was done to detect the normality of the result values. Kruskal-Wallis test was then performed to test the level of significance between groups.

RESULTS

After 20 minutes - Group I showed higher bacterial count mean values (5,500 ± 500) and 0 values for groups II and III groups. After 1 day, the highest bacterial count mean values were in group III (54,333.3 ± 4,041.5) and 0 values for groups I and II. After 3 days - group III again recorded the highest bacterial count mean values (45,000 ± 5,000) and 0 values for I and II groups. After 7 days - Group III still recorded the highest bacterial count mean values (53,333.3 ± 1,527.5) and 0 values for groups I and II. After 14 days - Group III recorded the highest bacterial count mean values (56,000 ± 1,000) followed by group II (6,333.3 ± 577.4), and the least was group I (2,000 ± 500). Kruskal-Wallis test showed significant values between groups in all tested durations, p > 0.05.

CONCLUSION

The sealing material AH Plus showed a strong bactericidal effect at the beginning but lost its ability after 24 hours. CeraSeal showed strong bactericidal activity from the beginning till the end of the first week but showed bacterial count at 14 days. Neoseal took 24 hours to show bactericidal effect and similar to CeraSeal showed bacterial count at 14 days; CeraSeal recorded the best results within the study.

CLINICAL SIGNIFICANCE

Silicate-based (bioceramic) endodontic sealers can be the best available endodontic sealing material that is clinically beneficial in removing residual microbes which had survived irrigation protocols and chemomechanical preparation. How to cite this article: Basta DG, Reslan MR, Rayyan M, et al. Evaluation of Antibacterial Effect of New Sealer "Neoseal" and Two Commercially Used Endodontic Sealers against Enterococcus faecalis: An In Vitro Study. J Contemp Dent Pract 2023;24(11):871-876.

Calcium Silicate-Based Sealer Dentinal Tubule Penetration-A Systematic Review of In Vitro Studies

The aim of this systematic review was to perform a qualitative synthesis of in vitro studies which evaluate and compare the penetration of calcium silicate-based sealers into dentinal tubules. A systematic advanced search was performed in Scopus, Embase, Medline (via PubMed), Web of Science, and Cochrane databases on the 1 December 2022. In vitro studies that compared the tubular penetration of at least two calcium silicate-based sealers in extracted human teeth were eligible. PRILE 2021 guidelines were used for the assessment of the risk of bias included studies. The search identified a total of 680 preliminary records, among which 12 studies were eligible for review. The most used methodology to evaluate sealer penetration was the use of a fluorochrome together with the tested sealers and the analysis of their penetration under confocal laser microscopy. Regarding the results of the included studies, calcium silicate-based sealers exhibit a favorable dentinal tubule penetration. Tubular penetration, however, can be affected by factors such as the irrigation protocol, sealer activation, the filling method used, and root canal morphology. EndoSequence BC Sealer showed the highest sealer penetration among the tested sealers. The influence of different fluorochromes on the results of dentinal tubule penetration studies should also be further explored. The in vitro nature of the included studies limits the applicability of the results into the clinical setting. Prospero registration: CRD42022383896.

Efficacy of Bioceramic and Calcium Hydroxide-Based Root Canal Sealers against Pathogenic Endodontic Biofilms: An In vitro Study

Background

Complete eradication of root canal pathogens cannot be predictably achieved by chemomechanical preparation and root canal disinfection. Therefore, an obturation material that has superior antimicrobial activity and sealing ability is required to inactivate residual microbes and prevent them from reentering the root canal system. Recently developed bioceramic root canal sealers are hydraulic cement which form calcium hydroxide during the hydration process. Like calcium hydroxide sealers, they exert an antimicrobial effect by releasing hydroxyl ions and increasing the pH.

Objective

The objective of this study was to evaluate and compare the antimicrobial activity of a calcium hydroxide-based sealer and two bioceramic sealers against Porphyromonas gingivalis, Enterococcus faecalis, and Candida albicans biofilms.

Materials and Methods

The sealers were dissolved in sterile saline to obtain supernatants. Biofilm formation assays, colony counting, and real-time polymerase chain reaction (PCR) were performed to evaluate the antimicrobial activity of each supernatant. The data were analyzed using one-way analysis of variance.

Results

All sealers exerted effects against all three microbial biofilms. The biofilm formation assays showed that the bioceramic sealers were more effective against P. gingivalis and E. faecalis biofilms. In contrast, colony counting and real-time PCR showed that the calcium hydroxide sealer was significantly more effective than the bioceramic sealers. All tests showed that the calcium hydroxide sealer was more effective against C. albicans, with the colony count and real-time PCR results showing statistically significant differences.

Conclusion

The calcium hydroxide-based sealer was more effective than the bioceramic sealers in eradicating pathogenic root canal biofilms.

In vitro physicochemical characterization of five root canal sealers and their influence on an ex vivo oral multi-species biofilm community

AIM

To evaluate the physicochemical properties of five root canal sealers and assess their effect on an ex vivo dental plaque-derived polymicrobial community.

METHODOLOGY

Dental plaque-derived microbial communities were exposed to the sealers (AH Plus [AHP], GuttaFlow Bioseal [GFB], Endoseal MTA [ESM], Bio-C sealer [BCS] and BioRoot RCS [BRR]) for 3, 6 and 18 h. The sealers' effect on the biofilm biomass and metabolic activity was quantified using crystal violet (CV) staining and MTT assay, respectively. Biofilm community composition and morphology were assessed by denaturing gradient gel electrophoresis (DGGE), 16S rRNA sequencing and scanning electron microscopy. The ISO6876:2012 specifications were followed to determine the setting time, radiopacity, flowability and solubility. Obturated acrylic teeth were used to assess the sealers' effect on pH. Surface chemical characterization was performed using SEM with coupled energy-dispersive spectroscopy. Data normality was assessed using the Shapiro-Wilk test. One-way anova and Tukey's tests were used to analyze data from setting time, radiopacity, flowability and solubility. Two-way anova and Dunnett's tests were used for the data analysis from CV, MTT and pH. 16S rRNA sequencing data were analyzed for alpha (Shannon index and Chao analysis) and beta diversity (Bray-Curtis dissimilarities). Differences in community composition were evaluated by analysis of similarity (p < .05).

RESULTS

The sealers significantly influenced microbial community composition and morphology. All sealers complied with ISO6876:2012 requirements for setting time, radiopacity and flowability. Although only AHP effectively reduced the biofilm biomass, all sealers, except BRR, reduced biofilm metabolic activity.

CONCLUSION

Despite adequate physical properties, none of the sealers tested prevented biofilm growth. Significant changes in community composition were observed. If observed in vivo, these changes could affect intracanal microbial survival, pathogenicity and treatment outcomes.

Present status and future directions: Hydraulic materials for endodontic use

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

In Vitro Evaluation of the Antibacterial Activity of EndoSeal MTA, iRoot SP, and AH Plus against Planktonic Bacteria

This study aimed to investigate the antibacterial activity of three endodontic sealers, AH Plus, iRoot SP, and EndoSeal MTA, against four planktonic bacteria species. The antibacterial activity of the three endodontic sealers was assessed using a modified direct contact test. Bacteria suspension of Actinomycoses viscosus, Enterococcus faecalis, Staphylococcus aureus, and Streptococcus mutans were left in contact with the sealers that were pre-set or set for 1, 3, 7, and l4 days for an hour. Freshly mixed AH Plus and EndoSeal MTA were highly effective against all four tested bacteria as no surviving bacteria were recovered after treatment. Meanwhile, freshly mixed iRoot SP was not able to kill all bacteria, regardless of the species, demonstrating a weak antibacterial effect. After 24 h, AH Plus lost its antibacterial activity. EndoSeal MTA showed a strong and extended bactericidal effect against S. aureus and S. mutans for 3 days and A. viscosus for 7 days. In conclusion, fresh AH Plus and EndoSeal MTA exhibited a potent effect against all four bacteria species. EndoSeal MTA remained effective after setting when tested against A. viscosus, S. aureus, and S. mutans. Among all tested sealers, iRoot SP demonstrates the weakest antibacterial activity.

The Short-Term Antibacterial Activity of Three Selected Endodontic Sealers against Enterococcus faecalis Bacterial Culture

(1) Background: Microorganisms originating from the microflora of the oral cavity are the main cause of the inflammatory diseases of the dental pulp and periapical periodontium, as well as the failure of endodontic treatment. The subsequent root canal treatment is not able to remove all the pathogens, and a small number of viable bacteria remain in the dentine tubules, which must be sealed by endodontic sealers. These sealers should have at least a bacteriostatic effect to prevent the remaining bacteria from reproducing. The aim of this study is to compare the short-term antibacterial activity of three endodontic sealers based on poly-epoxy resin, zinc oxide-eugenol and calcium silicate with a calcium hydroxide-based sealer. Calcium hydroxide is used as temporary intracanal medicament and, thus, should show significant antibacterial activity. (2) Methods: A total of 25 bovine dentine samples infected with Enterococcus faecalis were used in this study. After the sealer placement and a 24 h incubation period, the root canal walls were scraped, and the suspension of dentine fillings was used for a semi-quantitative evaluation of microbial growth. (3) Results: The poly-epoxide resin-based sealer ADSeal™ showed significant antibacterial properties. (4) Conclusions: The highest antibacterial activity was shown in poly-epoxide resin-based sealer group, followed by the zinc oxide-eugenol-based sealer and calcium silicate-based sealer.

Bacterial leakage assessment in root canals sealed with AH Plus sealer modified with silver nanoparticles

BACKGROUND

Successful endodontic therapy requires prevention of bacterial leakage between the root canal filing and root-canal walls. Sealing quality of a root canal filling depends strongly on the sealing ability of the sealer used. The present study aimed to evaluate the bacterial leakage resistance of AH Plus sealer modified with silver nanoparticles.

METHODS

Forty sound teeth were obturated using lateral compaction technique except for five teeth as the negative controls. After considering five teeth as the positive controls (filled without sealer), the remaining teeth were assigned to two groups (n = 15) in terms of the sealer used (AH Plus sealer and silver nanoparticle-modified AH Plus). Bacterial leakage was evaluated in saliva using the two-chamber technique in every 24 h. When all the samples in the test groups were contaminated, the study was terminated. The data were analyzed with log-rank statistical test.

RESULTS

All samples in both experimental groups were contaminated during the 3-months period of observation. There was no significant difference in contamination time between study groups (P > 0.05).

CONCLUSIONS

Silver nanoparticles used in tested concentration did not improve the bacterial leakage resistance of AH Plus sealer.

Comparison of Dentinal Tubule Penetration between a Calcium Silicate-Based Sealer with Ultrasonic Activation and an Epoxy Resin-Based Sealer: A Study Using Confocal Laser Scanning Microscopy

OBJECTIVE

 The aim of this study was to compare the degree of dentinal penetration between an epoxy resin-based sealer applied by using two different filling methods and an ultrasonically activated calcium silicate-based sealer via confocal laser scanning microscopy (CLSM).

MATERIALS AND METHODS

 Forty-five extracted permanent maxillary premolars with type II canals (Vertucci's classification) were subjected to the experiment. The root canals were instrumented and distributed randomly into the following three groups: AH Plus + continuous wave technique (AHC group); AH Plus + single cone technique (AHS group); and Endoseal MTA + single cone technique with ultrasonic activation (EMS) group. Each sealer was labeled with rhodamine B dye to allow visualization under CLSM. The sealer penetration depth in each sample was observed at 2 mm and 5 mm from the apex by using CLSM. The data were statistically analyzed by using analysis of variance or Kruskal-Wallis H test according to normality of variable (α = 0.05).

RESULTS

 In all groups, the maximum sealer penetration depth, mean fluorescence intensity, and sum fluorescence intensity values were higher at the 5-mm level than at the 2-mm level. At the 5-mm level, the EMS group showed the lowest value (p = 0.02). At the 2-mm level, there were no statistically significant differences among any of the groups. The AHC group showed higher values than the other groups, but there was no statistically significant difference in the apical area where access of instruments was difficult.

CONCLUSION

 The AHC group showed the highest dentinal tubule penetration, but had questionable filing efficacy in the apical area, which is of particular importance for the success of root canal treatment. Therefore, in areas such as the apical 2 mm of premolars with type II canals, which are difficult to access by using instruments such as heat carriers, other appropriate approaches may be required accordingly.

Main and Accessory Canal Filling Quality of a Premixed Calcium Silicate Endodontic Sealer According to Different Obturation Techniques

The present study aimed to investigate the effects of different obturation techniques on the main and accessory canal filling quality of a premixed calcium silicate endodontic sealer (Endoseal TCS). We also highlighted the validity of the methods used for evaluating the canal filling quality. Thirty single-rooted premolars were used for the main canal filling and 75 were used for accessory canal filling. The canals were instrumented and randomly divided into three groups according to the filling techniques: (1) single-cone technique (SC), (2) single-cone with ultrasonic activation (SU), and (3) warm vertical compaction (WV). Voids in relation to the root canal fillings were assessed using cross-section images from microcomputed tomography (μCT) scans or transversely sectioned tooth specimens (n = 10). After demineralization and clearing of the teeth, the incidence, number, and completeness of the accessory canal fillings were evaluated (n = 25). One-way analysis of variance (ANOVA) and Tukey's post hoc test was used for the evaluation of the voids in the main root canal and the incidence and number of filled accessory canals. Pearson's chi-squared (χ²) test was used for the evaluation of the filling completeness (α = 0.05). In the stereomicroscopic evaluation of the sectioned specimen, the SC group had significantly higher void occurrence than the other groups (p < 0.05), although there was no difference between groups in the μCT evaluation. However, there was no difference between the SU and WV. There was no difference between all the groups regarding the incidence, number, and completeness of the accessory canal fillings. When the premixed calcium silicate sealer is used with SC, the ultrasonic activation is recommended to obtain a better main canal filling quality. In contrast, the obturation techniques did not affect the accessory canal filling. We also recommend using the sectioning method when the void formation in the root canal filling materials is evaluated.

Antimicrobial activity and biocompatibility of the mixture of mineral trioxide aggregate and nitric oxide-releasing compound

Background/purpose

Antimicrobial activity and biocompatibility of root canal sealer are related to the success of endodontic treatments. This study investigated the efficacy of mixture of mineral trioxide aggregate (MTA) and a NO-releasing compound for the antimicrobial activity, biocompatibility, and physical properties.

Materials and methods

MTA was mixed with diethylenetriamine-NO (MTA-NO), and the extracts from MTA and the MTA-NO mixture before and after setting was obtained were investigated the antimicrobial activity against Enterococcus faecalis and Porphyromonas endodontalis. After setting MTA and MTA-NO, pulp cell was incubated in the presence of MTA and MTA-NO disk using Transwell® cell culture insert, and the proliferation assay and mineralization-stimulated factors of the cells were analyzed by MTT assay and real-time RT-PCR, respectively. The physical properties of MTA and the MTA-NO mixture, such as surface hardness and flowability was also analyzed.

Results

The MTA-NO mixture showed stronger antimicrobial activity against E. faecalis and P. endodontalis than that by MTA. Both MTA and MTA-NO mixture increase the ratio of cell proliferation and induced the expression of alkaline phosphatase, collagen type I, osteocalcin, and osteopontin. Moreover, the induction of gene expression by MTA-NO mixture was higher than that by MTA alone. No significant difference was observed for surface hardness and flowability between MTA and MTA-NO mixture.

Conclusion

The addition of a NO-releasing compound to the endodontic treatment using MTA root canal sealer might reduce the risk of bacterial infection and help to regenerate the dental pulp tissue.

Calcium silicate-based root canal sealers: a literature review

Epoxy resin-based sealers are currently widely used, and several studies have considered AH Plus to be the gold-standard sealer. However, it still has limitations, including possible mutagenicity, cytotoxicity, inflammatory response, and hydrophobicity. Drawing upon the advantages of mineral trioxide aggregate, calcium silicate-based sealers were introduced with high levels of biocompatibility and hydrophilicity. Because of the hydrophilic environment in root canals, water resorption and solubility of root canal sealers are important factors contributing to their stability. Sealers displaying lower microleakage and stronger push-out bond strength are also needed to endure the dynamic tooth environment. Although the physical properties of calcium silicate-based sealers meet International Organization for Standardization recommendations, and they have consistently reported to be biocompatible, they have not overcome conventional resin-based sealers in actual practice. Therefore, further studies aiming to improve the physical properties of calcium silicate-based sealers are needed.

Antimicrobial Activity of Nano-Magnesium Hydroxide Against Oral Bacteria and Application in Root Canal Sealer

BACKGROUND The goal of the present work was to assess the antibacterial activity of nano-magnesium hydroxide (NMH) against Streptococcus mutans (S. mutans) and to explore the antimicrobial function of AH Plus™ sealer incorporating NMH. MATERIAL AND METHODS The antimicrobial behavior of NMH against S. mutans was evaluated with bactericidal tests. A modified direct contact test was used to assess the antimicrobial activity of unset AH Plus containing NMH after 5 minutes, 20 minutes, and 60 minutes of contact with bacteria. The antimicrobial effects and the amount of surface-adhering bacteria of the solidified materials were explored by SEM and confocal laser scanning microscopy, respectively. RESULTS NMH powder presented excellent antimicrobial activity against S. mutans. Mg²⁺ and OH⁻ were not the main factors resulting in bacterial death. Approximately 93.1% and 98% of the S. mutans were killed in the AH Plus+7% NMH group after incubation for 5 minutes and 20 minutes, respectively. AH Plus with 5% or 7% NMH were more potent against S. mutans compared with AH Plus alone (P<0.05). Moreover, the antibacterial function of AH Plus was lost after setting. NMH enabled the solidified AH Plus to still have antibacterial properties on the seventh day. CONCLUSIONS NMH can be used to modify AH Plus sealer to eradicate residual bacteria and prevent reinfection.

Sealing Ability of Endodontic Cements: An In Vitro Study

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

Antimicrobial efficacy of commercially available endodontic bioceramic root canal sealers: A systematic review

Background

Recently, a new generation of bioceramic root canal sealers has been introduced onto the market. Many in vitro studies have investigated the antimicrobial properties of these sealers, but their comparative efficacy in antimicrobial activity is still unknown.

Methodology

Three electronic databases were searched: MEDLINE and Embase via the OvidSP platform, and Web of Science, up to June 25, 2019. Studies were included irrespective of study design, type of publication and language. Reporting quality was assessed by two authors independently. Meta-analysis was not performed due to studies being highly heterogeneous.

Results

We included 37 studies that analysed the antimicrobial effects of bioceramic sealers. Most of them used a planktonic cell model, with the exception of nine studies which used biofilms. It was not possible to make direct comparison of results from studies and to give a clear conclusion about the comparative antimicrobial activity of these materials because the studies used heterogeneous sources and ages of microorganisms, setting and contact times of sealers, and antimicrobial tests. Furthermore, some materials showed completely different results when tested with different methods.

Conclusions

In conclusion, multiple in vitro studies have shown that bioceramic sealers may have various degrees of antimicrobial activity. However, it is still impossible to make conclusions about their comparative efficacy and to recommend the use of one over another in clinical practice because the studies available were conducted in different ways, which makes meta-analysis futile. A uniform methodological approach, consistent definitions and studies on humans are urgently needed in this field of research so that recommendations for practice can be made.