Analysis of the physicochemical properties, cytotoxicity and volumetric changes of AH Plus, MTA Fillapex and TotalFill BC Sealer

Influence of Various Irrigation Protocols on the Push-Out Bond Strength of TotalFill and AH Plus Bioceramic Sealers to Root Dentin: A Comparative In Vitro Study

This study aimed to compare the push-out bond strength (POBS) of TotalFill (TFB) and AH Plus bioceramic (APB) sealers with different irrigation protocols.Sixty maxillary central incisors were prepared and randomly divided into three groups (n = 10) based on the final irrigation protocol. Group NC: 5.25% sodium hypochlorite (NaOCl); Group NE: 5.25% NaOCl and 17% EDTA; Group NH: 5.25% NaOCl and dual rinse HEDP (1-hydroxyethylidene-1,1-diphosphonic acid). Samples were obturated using either TFB or APB sealer only. In groups NC and NE, NaOCl was used during canal preparation, while in Group NH, NaOCl/HEDP was utilized. The teeth were then horizontally sectioned into three 3-mm thick sections at the apical, middle, and coronal levels. The POBS was performed on the root sections at a 1 mm/min speed. The failure mode was assessed using an optical microscope and a scanning electron microscope.Two-way ANOVA (analysis of variance) was used for statistical analysis to test the interaction between sealer type and irrigation solution, while an independent t-test was conducted to compare the means of the two sealer types at a significance level of 0.05.Specimens obturated with TFB showed significantly higher POBS than APB (p < 0.001). The highest bond strength was observed in the HEDP/TFB group and the lowest in the HEDP/APB group. Irrigation did not significantly influence the POBS (p > 0.05). Mixed failure was most commonly observed in all groups (>65%).TFB sealer had improved bond strength over APB sealer, regardless of the final irrigation protocol used, which did not significantly affect the bond strength.

Comparative analysis of the inflammatory response of human gingival fibroblasts to NeoSEALER Flo and CeraSeal bioceramic sealers: an in vitro study

BACKGROUND

Therapeutic quality of endodontic sealers plays a critical role in promoting the success of root canal therapy by blocking entrance of microbes as well as facilitating tissue reparative process. The bioceramic sealers NeoSEALER Flo and CeraSeal have been on the rise owing to their biocompatibility and bioactivity. However, their relations with periapical tissues especially human gingival fibroblasts (HGFs) are still significant determinants of treatment outcomes. This in vitro case intends to analyze the inflammatory reaction of HGFs towards NeoSEALER Flo and CeraSeal bioceramic sealers and AH plus resin sealer as control.

MATERIALS AND METHODS

HGFs were cultured and treated with eluates of tested sealers at different dilutions; 25%, 50%, 75% and 100%. The extracts were left in incubator for 1, 3, and 7 days. Cell death was determined by the MTT assay, and the secretion levels of pro-inflammatory cytokines such as IL-6, IL-8, and TNF-α, were measured using q RT-PCR. Furthermore, mRNA and protein levels of some inflammatory markers were also estimated by q RT-PCR.

RESULTS

Analysis of the data showed that NeoSEALER Flo was cytotoxic in a concentration-dependent manner to HGFs, though it appeared marginally more toxic than CeraSeal when tested at the same ratios and same time. The high levels of all the measured pro-inflammatory cytokines in HGFs treated with both sealers at a higher concentration with NeoSEALER Flo showing a more intense effect. Having said so, gene expression profiles endorsed these results by showing that both sealers increase the level of IL-6, IL-8, and TNF-α at the higher concentrations.

CONCLUSIONS

The study indicates that both NeoSEALER Flo and CeraSeal bioceramic sealers activate HGFs inflammatory response with a slight preference for CeraSeal biocompatibility. Therefore, it becomes important and relevant to assess the cytotoxic and inflammatory propensity of various endodontic materials in order to guide enrolment of these endodontic products in clinical practice and improve the quality of endodontic treatment. Subsequent in vivo works should be done to confirm these in vitro findings as well as to examine the chronic effects of sealer-tissue interaction.

Physicochemical properties of silicate tricalcium-based cement for use as pulp capping or repair material

This study evaluated some physicochemical properties of an experimental tricalcium silicate-based cement (ETSC) indicated for use as pulp capping or endodontic repair material; Biodentine (BD) and White MTA-Angelus (MTA) cements served as comparators. Setting time, radiopacity, sorption, and solubility were determined according to ISO 6876/2012 and compressive strength according to ISO 9917-1/2019. pH and calcium ion release capacity were also assessed. Data were analyzed using ANOVA and Tukey tests or Kruskal-Wallis and Dunn tests with α = 0.05. BD (15') and ETSC (17.3') exhibited the shortest initial setting times, with BD (29') having the shortest final setting time; MTA showed longer times in both analyses (p < 0.05). ETSC and MTA showed the highest radiopacity (6.1 mm Al and 5.7 mm Al), while BD showed the lowest (3.0 mm Al) (p < 0.05). BD exhibited the highest compressive strength (88.8 MPa), significantly higher than the others (p < 0.05). BD presented the lowest values for sorption, 0.12% (24 h) and 0.48% (28 d), which differed significantly from MTA (p < 0.05). The lowest values for solubility were shown for ETSC, 0.26% (24 h), and BD, 0.52% (28 d), which differed significantly from MTA (p<0.05). ETSC showed the highest pH throughout all periods; significant differences were observed for MTA (3 h) and BD (24 h) (p<0.05). In the Ca2+ analysis, BD provided the highest values in all periods; differences were only significant compared to MTA (3h/24h) (p <0 .05). Considering the study conditions, it can be concluded that ETSC exhibited characteristics similar or better properties than the commercial cements tested, except for compressive strength.

Micro-Computed Tomography Analysis of Resin and Calcium Silicate Based Sealers Removal in Mandibular Molars Curved Canals

Objective

The removal of the root canal sealer is an important factor in nonsurgical retreatment. The aim of this study was to compare the removal of AH Plus, Well Root ST, and AH Plus Bioceramic Sealer using Protaper Universal retreatment files.

Methods

The curved mesio-buccal canals of extracted mandibular molars were prepared with the Protaper Gold file system (up to F2). Specimens were randomly divided into 3 groups and filled with the single cone technique using AH Plus, Well-Root ST, and AH Plus Bioceramic Sealer, respectively. After two weeks, the root canal filling of all specimens was removed using Protaper Universal retreatment files. All specimens were scanned using micro-CT. The remaining volume of the root canal filling was recorded in total and the coronal, middle, and apical third of each specimen.

Results

Well-Root ST and AH Plus Bioceramic Sealer groups had a higher percentage of total remaining filling material than the AH Plus group (P<0.05).

Conclusion

This study has shown that the volume of remaining root canal filling was significantly higher in the samples filled with calcium silicate-based sealers.

Evaluation of the antibacterial and cytotoxic properties of TotalFill and NeoSEALER flo bioceramic sealers

Aim

Evaluation of the antibacterial and cytotoxic properties of TotalFill and NeoSEALER Flo bioceramic sealers compared to AH Plus resin sealer.

Materials and Methods

Modified direct contact test was used on three sets of sealers: Freshly mixed sealers, sealers that were 1-day old, and sealers that were 7-day old. After 24 h of incubation, the colony-forming units were digitally counted using Promega Colony Counter after 30 and 60 min of exposure to Enterococcus faecalis. For cytotoxic effect evaluation, 3-(4,5-dimethylthiazol-2-yl)-2-5-diphenyltetrazolium bromide assay was performed at three different time points: 24 h, 48 h, and 120 h after adding the sealer eluates to human gingival fibroblasts, to assess cell viability. Data were analyzed using mixed model analysis of variance followed by post hoc test.

Results

TotalFill bioceramic sealer showed the highest bacterial reduction against E. faecalis throughout all intervals. AH Plus showed great antibacterial activity initially which reduced drastically after 7 days. All the sealers showed a reduction in their antibacterial activity with time. TotalFill and NeoSEALER Flo showed very high cell viability in contrast to AH Plus.

Conclusion

TotalFill and NeoSEALER Flo demonstrate superior antimicrobial properties against E. faecalis which reduces with time. TotalFill and NeoSEALER Flo demonstrate acceptable biocompatibility against human gingival fibroblasts, which decreased over time.

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.

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.

Comparison of the dentin tubule penetration of AH Plus, WellRoot ST, and MTA BioSeal after obturation, retreatment, and re-shaping of the root canals

It was aimed to compare the dentine tubule penetration of AH Plus, MTA Bioseal, and WellRoot ST after filling, retreating, and reshaping the root canals by using a novel microscopic method. Seventy-five mandibular incisors with single root canals were shaped with Protaper Next system (PTN; X2-25/0.06) The teeth were obturated with AH Plus labeled with Rhodamin B and MTA Bioseal or WellRoot ST sealer which were labeled with Fluo-3. Then the root canal fillings were removed with Protaper Universal Retreatment files. At the last stage, the teeth were reshaped with PTN (X3-30/0.07). The samples were transversally sectioned and examined using a Cytation 5 reader and Gen5 software regarding the mean and the maximum depth of sealer penetration. No significant difference was observed between the groups, except for the 6 mm level after reshaping the root canals (p < .05). It is not possible to completely remove the sealer remnants from the dentin walls even after reshaping the root canals. RESEARCH HIGHLIGHTS: Even after reshaping the root canals in the retreatment procedure, it is not possible to completely remove the filling residues of the epoxy-resin-based, calcium-silicate-based and MTA-based endodontic pastes from the dentin walls.

A comparative study of biological properties of three root canal sealers

OBJECTIVES

The aim of this study was to evaluate the effects of Hiflow with other two kinds of root canal sealers on the biological behavior of stem cells from the apical papilla (SCAP), the influence on inflammatory cytokines release and its antibacterial effects.

MATERIALS AND METHODS

Material extracts of Hiflow, iRoot SP, and AH Plus were prepared. Then, SCAP was incubated with extracts. The effects were evaluated by CCK-8, wound healing assay, ALP staining, alizarin red staining, and qRT-PCR. Meanwhile, polymorphonuclears (PMNs) and monocytes were isolated and treated with extracts for 4 h and 24 h respectively. Cell viability was analyzed by Annexin-V/PI double staining flow cytometry. The effects on the release of cytokines were observed by ELISA. The antibacterial effects of different sealers were tested against three kinds of bacteria found in chronic apical periodontitis.

RESULTS

A series of results of SCAP showed that Hiflow and iRoot SP could promote cell proliferation, migration, and osteogenesis (p < 0.05). Although Hiflow was associated with greater cell apoptosis and necrosis when incubated with PMNs and monocytes (p < 0.05), it had an approximate release of anti-inflammatory cytokines with iRoot SP, which was higher than AH plus (p < 0.05). The co-culture showed that Hiflow and iRoot SP inhibited the colony formation of F. nucleatum (p < 0.05). However, both sealers had no obvious antibacterial effect on E. faecalis and P. gingivalis (p > 0.05).

CONCLUSIONS

In summary, Hiflow and iRoot SP both had positive biological stimulus on SCAP. Meanwhile, Hiflow showed a better induction on anti-inflammatory cytokines over the others. All the properties mentioned above and its antibacterial effect of F. nucleatum promise Hiflow a bright application prospect in endodontic uses.

CLINICAL RELEVANCE

References for clinical work to use BC Sealer Hiflow as a good biological root canal sealer.

Evaluation of the Impact of Calcium Silicate-Based Sealer Insertion Technique on Root Canal Obturation Quality: A Micro-Computed Tomography Study

BACKGROUND

Calcium silicate-based sealers have gained in popularity over time due to their physicochemical/biological properties and their possible use with single-cone obturation. The single cone technique is a sealer-based obturation and there is still a knowledge gap regarding the potential impact of the sealer insertion method on the root canal-filling quality. Therefore, the aim of this micro-CT study was to assess the impact of the calcium silicate-based sealer insertion technique on void occurrence and on the sealer extrusion following single-cone obturation.

METHODS

Thirty-six single-rooted mandibular premolars with one canal were shaped with Reciproc® R25 (VDW, Munich, Germany) then divided randomly into four groups of nine canals, each depending on the TotalFill® BC Sealer insertion technique used with single cone obturation: injection in the coronal two-thirds (group A); injection in the coronal two-thirds followed by direct sonic activation (group B); injection in the coronal two-thirds followed by indirect ultrasonic activation on tweezers (group C); sealer applied only on the master-cone (control group D). Samples were then scanned using micro-CT for voids and sealer extrusion calculation. Data were statistically analyzed using v.26 IBM; Results: No statistically significant differences were noted between the four groups in terms of voids; nevertheless, sonic activation (group B) followed by ultrasonic activation on the tweezers (group C) showed the best results (p = 0.066). Group D showed significantly less sealer extrusion when compared with group C (p = 0.044), with no statistically significant differences between groups D, A and B (p > 0.05).

CONCLUSIONS

Despite no significant differences observed between the different sealer placement techniques, the use of sonic and ultrasonic activation might be promising to reduce void occurrence. Further investigations are needed to demonstrate the potential benefit of calcium silicate-based sealer activation especially in wide and oval root canals in order to improve the quality of the single-cone obturation.

A scientometric, bibliometric, and thematic map analysis of hydraulic calcium silicate root canal sealers

OBJECTIVES

This scientometric and bibliometric analysis explored scientific publications related to hydraulic calcium silicate-based (HCSB) sealers used in endodontology, aiming to describe basic bibliometric indicators and analyze current research trends.

MATERIALS AND METHODS

A comprehensive search was conducted in Web of Science and Scopus using specific HCSB sealer and general endodontic-related terms. Basic research parameters were collected, including publication year, authorship, countries, institutions, journals, level of evidence, study design and topic of interest, title terms, author keywords, citation counts, and density.

RESULTS

In total, 498 articles published in 136 journals were retrieved for the period 2008-2023. Brazil was the leading country, and the universities of Bologna in Italy and Sao Paolo in Brazil were represented equally as leading institutions. The most frequently occurring keywords were "calcium silicate," "root canal sealer MTA-Fillapex," and "biocompatibility," while title terms such as "calcium," "sealers," "root," "canal," "silicate based," and "endodontic" occurred most often. According to the thematic map analysis, "solubility" appeared as a basic theme of concentrated research interest, and "single-cone technique" was identified as an emerging, inadequately developed theme. The co-occurrence analysis revealed 4 major clusters centered on sealers' biological and physicochemical properties, obturation techniques, retreatability, and adhesion.

CONCLUSIONS

This analysis presents bibliographic features and outlines changing trends in HCSB sealer research. The research output is dominated by basic science articles scrutinizing the biological and specific physicochemical properties of commonly used HCSB sealers. Future research needs to be guided by studies with a high level of evidence that utilize innovative, sophisticated technologies.

Analysis of physicochemical properties of endodontic sealers containing rhodamine B

The use of fluorescent dyes in microscopy studies is frequent. Therefore, it is important to investigate whether these compounds may alter the physicochemical properties of materials in which they are incorporated to avoid methodological biases. This study evaluated the physicochemical properties of two endodontic sealers containing dry or diluted rhodamine B. Six groups were evaluated: AH Plus and MTA Fillapex in their original composition and mixed with 0.1% dry or diluted rhodamine. Push-out test was applied to assess the bond strength to root dentin. ANSI-ADA No. 57 and ISO No. 6876:2012 specifications were followed to evaluate flowability, setting time, and solubility of the sealers. pH changes were assessed after 24 h, 7, and 30 days. Intergroup comparisons were analyzed by ANOVA complemented by Tukey's post-hoc test; comparisons among periods were analyzed by Wilcoxon and Friedman tests. The incorporation of dry rhodamine decreased the bond strength and prolonged the setting time of AH Plus. The incorporation of diluted rhodamine decreased the setting time and increased the flowability of MTA Fillapex. Diluted rhodamine promoted pH reduction of AH Plus after 24 h and dry rhodamine after 7 days. Rhodamine incorporation promoted pH reduction after 30 days for MTA Fillapex. Solubility was not affected. In conclusion, the incorporation of diluted rhodamine changed the properties of MTA Fillapex, and the incorporation of dry rhodamine changed the properties of AH Plus. Previous dilution of rhodamine did not severely compromise the physicochemical properties of AH Plus and may be suggested to assess its penetrability.

Does the ultrasonic activation of calcium silicate-based sealers affect their physicochemical properties?

This study aimed to evaluate the influence of ultrasonic activation (UA) on the physicochemical properties of hydraulic calcium silicate-based sealers. Nine experimental conditions were created based on the hydraulic calcium silicate-based sealers (Bio-C Sealer, Sealer Plus BC and Bio Root RCS) and the ultrasonic activation (no activation [NA], 10 seconds, and 20 seconds). Then the experimental groups were BC-NA, BC-10, BC-20, SPBC-NA, SPBC-10, SPBC-20, BR-NA, BR-10, and BR-20. Activation was performed with an ultrasonic insert 20/.01. The mold for the physicochemical analysis was filled and evaluated according to the ANSI/ADA specification nº. 57: initial and final setting time, flow, radiopacity and solubility. Tests were also performed to evaluate pH and calcium ion release with experimental periods of 1, 24, 72, and 168 hours with a pH meter and colorimetric spectrophotometer. Data were analyzed by one-way analysis of variance and post-hoc Tukey tests. The significance level was set at 5%. The time of UA progressively delayed the initial setting time for all hydraulic calcium silicate-based sealers (p < 0.05). Twenty seconds of UA increased the mean flow values of Sealer Plus BC and Bio-C Sealer compared to NA (p < 0.05). UA did not influence the radiopacity and solubility of the tested sealers (p > 0.05). UA for 20 seconds enhanced the pH levels and the calcium ion release of Sealer Plus BC and Bio-C Sealer at 168h (p < 0.05). UA for twenty seconds interferes with some physicochemical properties of hydraulic calcium silicate-based sealers.

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.

The Biological and Mechanical Effect of Using Different Irrigation Methods on the Bond Strength of Bioceramic Sealer to Root Dentin Walls

Objectives This study aimed to evaluate the biological and mechanical effect of different irrigation methods on the bond strength of Bioceramic (BC) sealer to root canal dentin walls. Material and Methods Forty-Five single-rooted teeth were decoronated and then prepared using rotary instrumentation. Teeth were randomly divided into three groups. Group 1: using the conventional syringe method; Group 2: using the ultrasonic (US) activation method; and Group 3: using the Nd:YAG laser activation method. The BC sealer (TotalFill® BC Sealer™, FKG Dentaire, Switzerland) was used for obturation according to the manufacturer's recommendation. The bond strength was evaluated using the push-out test, and the adaptation of the sealer/dentin interface was assessed using Scanning Electron Microscope (SEM). Data were analyzed by Welch's ANOVA analysis of variance and Games-Howell for pairwise comparison. The level of statistical significance was set at 95% (p-value ≤ 0.05). Results The push-out bond strength values of the Nd:YAG (6.46 ± 0.5) laser group were statistically significant than both conventional (3.33 ± 1.8) and US groups (4.21 ± 2.2). The mean gaps that were formed between the root walls and GP/BS sealer interface were statistically significant only between the Nd:YAG laser group (25.54 ± 13.8) compared to both conventional (62.00 ± 15.3) and US groups (58.82 ± 23.8) (p ≤0.05). No significant difference was found between the conventional and US groups in both rested parameters (p >0.05). Conclusion The method protocol of RC system irrigation affects the adhesion and bond strength of BS sealers to the root canal dentin walls.

Methodological proposal for evaluation of adhesion of root canal sealers to gutta-percha

AIM

To compare the bond strength of an epoxy resin-based sealer and two calcium silicate-based sealers (CSS) to gutta-percha discs using a new method.

METHODOLOGY

Round discs of gutta-percha (n = 60), measuring 10 mm in diameter and 2 mm in thickness, were placed on a glass plate and a drop of each sealer (AH Plus, EndoSequence BC Sealer and EndoSeal MTA) was placed on their surface. Another identical disc was placed onto the first one and a standardized weight (0.0981 N) applied over them using a specially developed apparatus. Ten samples prepared for each sealer were submitted to a microshear bond strength test accomplished by a specially designed set-up coupled to a universal testing machine. The Kruskal-Wallis test followed by a post hoc procedure was used to compare groups considering the preliminary analysis of the raw data had indicated the nonadherence to a Gaussian distribution (Shapiro-Wilk, p < .05). Alpha error was set at 5%.

RESULTS

Overall, no premature failure occurred. All sealers had some degree of adhesiveness to gutta-percha discs but with a significant difference amongst them (Kruskal-Wallis, p = .019). The epoxy resin-based sealer (AH Plus) had significantly higher median shear bond strength values (1.43 MPa; 1.40-1.83) compared to EndoSeal MTA (0.53 MPa; 0.46-0.73) (p = .021) and EndoSequence BC Sealer (0.45 MPa; 0.34-0.46) (p = .023), whilst the lowest median value was observed with EndoSequence BC Sealer (0.45 MPa; 0.34-0.46) (p < .05).

CONCLUSIONS

CSS sealers had weaker bonding to gutta-percha when compared to the epoxy resin-based AH Plus sealer. The proposed methodology is an innovative and reproducible method for testing the bond strength of root canal sealers to gutta-percha.

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.

Antibacterial, biological, and physicochemical properties of root canal sealers containing chlorhexidine-hexametaphosphate nanoparticles

OBJECTIVE

The aim of this study was to evaluate the influence of the incorporation of chlorhexidine-hexametaphosphate nanoparticles (CHX-HMP NPs) on antibacterial, cytotoxic and physicochemical properties of AH Plus (AH), MTA Fillapex (MTA) and Pulp Canal Sealer (PCS).

METHODS

The NPs were synthesized and characterized by Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), zeta potential, Atomic Force Microscopy (AFM) and Energy-Dispersive X-ray Spectroscopy (EDS). The incorporation was made by weight, 2% and 5% of NPs. The antimicrobial activity, cytotoxicity, flow, radiopacity, setting time, solubility and pH were evaluated. The statistical analysis was performed by two-way analysis of variance test and Tukey post hoc test (P < 0.05).

RESULTS

SEM analysis showed the tendency for CHX-HMP NPs to cluster, the effective mean diameter measured by DLS: 169.39 nm and the zeta potential: -10.18 mV. The NPs were individually measured by AFM: 22.99-52.75 nm. EDS analysis identified the presence of C, N, O, Na, P, Cl. After incorporation: The Direct Contact Test showed an increase in the antimicrobial action of AH, PCS and MTA; the sealers showed a decrease in flow and at 24 h of immersion also an increase in solubility, but did not affect the radiopacity of the samples; AH setting time increased and MTA did not reach setting under any of the conditions tested. All samples showed a decrease in pH value as the immersion time progressed.

SIGNIFICANCE

The incorporation of NPs can improve the antimicrobial performance of endodontic sealers without impairing other biological and physicochemical properties.