Epoxy Resin Sealer Research Articles

Minimal Dentinal Tubule Penetration of Endodontic Sealers in Warm Vertical Compaction by Direct Detection via SEM Analysis.

Sealer staining using rhodamine B dye to investigate the penetration depth of endodontic sealers was proven unsuitable for this purpose. This study aimed to investigate the sealer penetration depth into dentinal tubules by scanning electron microscopy (SEM). Root canals of 52 human upper central incisors were instrumented using the ProTaper Gold NiTi system (Dentsply Sirona, York, PA, USA) up to size F3. After irrigation with sodium hypochlorite and citric acid combined with ultrasonic activation, the root canals were either filled using the epoxy resin sealer AH Plus (Dentsply Sirona) or the calcium silicate-based sealer Total Fill BC Sealer HiFlow (TFHF, FKG Dentaire, La Chaux-de-Fonds, Switzerland) by warm vertical compaction. Root slices of 1 mm thickness were obtained at 2 to 3, 5 to 6 and 8 to 9 mm from the apex. The root slices were investigated for sealer penetration into the dentinal tubules using SEM according to four root quadrants (buccal, mesial, oral, distal). Statistical analysis was performed by the Kruskal-Wallis test (p = 0.05) as data were not normally distributed according to the Shapiro-Wilk test. AH Plus penetrated significantly deeper into the dentinal tubules compared to TFHF at each root level (p < 0.05). Dentinal sealer penetration was deeper in the bucco-oral direction compared to the mesio-distal direction. AH Plus penetrated deeper into dentinal tubules than TFHF. Warm vertical compaction exerting high pressure on the root canal filling material is not able to press sealers deep into dentinal tubules as penetration depth values did not exceed a mean of 110 µm in SEM.

Assessment of Root Canal Sealers Loaded with Drug-Silica Coassembled Particles Using an In Vitro Tooth Model

IntroductionThe purpose of this study was to assess the antimicrobial activity of root canal sealers modified with novel highly loaded antimicrobial drug-silica coassembled particles (DSPs) on Enterococcus faecalis–infected root canal dentin. MethodsDSPs were synthesized through coassembly of silica and octenidine dihydrochloride (OCT) surfactant drug (35% w/w OCT). DSPs (1% wt of the total mass of the sealer) were mixed homogenously with either epoxy resin sealer (AH Plus [AH]; Dentsply Sirona, Tulsa, OK) or calcium silicate–based sealer (EndoSequence BC Sealer [BC]; Brasseler, Savannah, GA). To assess the antimicrobial activity of DSP-loaded sealers, the apical third of single-rooted teeth was obtained and infected with E. faecalis for 3 weeks followed by the application of experimental (DSP-loaded) sealers or corresponding controls for up to 28 days. Microbiological analysis and laser scanning confocal and scanning electron microscopy were used to determine the colony-forming unit (CFU)/mL, the percentage of live bacteria, and the intratubular bacterial and sealer penetrations. Factorial analysis of variance and Tukey post hoc tests were used to assess the antimicrobial effect of DSPs on different sealers. ResultsAll experimental groups showed significant reductions in CFUs at all-time points compared with positive controls (P < .05). The addition of DSPs to BC significantly reduced the CFUs (2.11 ± 0.13, 2.22 ± 0.19, and 2.25 ± 0.17 at 1, 7, and 28 days, respectively) compared with the unmodified sealer (3.21 ± 0.11, 4.3 ± 0.15, and 4.2 ± 0.2 at 0, 7, and 28 days). DSPs enhanced the antimicrobial performance of AH only at 1 day (4.21 ± 0.17 vs 5.19 ± 0.12, P < .05). AH and AH + DSPs showed higher bacterial viability compared with BC and BC + DSPs at all incubation periods (P < .05). ConclusionsLoading endodontic sealers with DSPs had a material-dependent effect on the antimicrobial properties and could reduce the incidence of secondary infections.

The impact of irrigation protocols on epoxy sealer penetration depth in dentinal tubules. Study involving laser confocal microscopy.

The aim was to assess the impact of irrigation protocols ended with ethanol or chlorhexidine on AH Plus penetration into dentinal tubules. 45 root canals were prepared to ISO 40/04, divided into three groups and irrigated with three protocols: Group 1 (control): 5.25% NaOCl; Group 2: 40% CA (citric acid), 5.25% NaOCl, 40% CA, water, ethanol; Group 3: 40% CA, 5.25% NaOCl, 40% CA, water, 2% chlorhexidine. Canals were filled using vertical condensation technique with gutta-percha and fluorescein-stained AH Plus sealer. After 72 h, 1 mm thick cross-sections were cut at 2, 5, 8 mm from the apex. Confocal laser microscope was used to measure the sealer penetration into dentinal tubules. Mean depth of sealer penetration (in micrometres) was 107, 131, 170 (Group 1); 146, 233, 317 (Group 2); 185, 301, 542 (Group 3); in apical, middle and coronal parts, respectively. Irrigation protocol ended with chlorhexidine resulted in the deeper sealer penetration compared with alcohol.

Debunking the Concept of Dentinal Tubule Penetration of Endodontic Sealers: Sealer Staining with Rhodamine B Fluorescent Dye Is an Inadequate Method.

The aim of this study was to investigate the suitability of rhodamine B dye staining of an epoxy resin sealer (AH Plus) and calcium-silicate-based sealers (Total Fill BC Sealer, BioRoot RCS) to represent the penetration depth of the sealers into dentinal tubules after root canal obturation. In a three-step process, (1) leaching of rhodamine B from sealers into a buffer solution, (2) passive penetration of leached rhodamine B into dentinal tubules, and (3) conformity of rhodamine B penetration assessed by confocal laser scanning microscopy (CLSM), and sealer penetration assessed by scanning electron microscopy (SEM), in root-canal-filled teeth, were evaluated. Rhodamine B dye massively leached out of Total Fill BC Sealer and BioRoot RCS into the phosphate-buffered saline (PBS). A pinkish coloration of AH Plus was found after contact with PBS. Leached rhodamine B dye passively penetrated dentinal tubules from all three sealers when placed on root dentin. No correlation was observed between sealer penetration in SEM and rhodamine B penetration in CLSM. Staining of sealers using rhodamine B is an inadequate method with which to evaluate sealer penetration depth into dentinal tubules, as it overestimates the penetration of sealers into root dentin tubules.

What’s new for the clinician? - Excerpts from and summaries of recently published papers

Choosing an endodontic sealer clinical use is a decision that contributes to the long-term success of non-surgical root canal treatment. Sealers are used as a thin tacky paste which function as a lubricant and luting agent during obturation, allowing the core obturation material, such as gutta-percha points or other rigid materials, to slide in and become fixed in the canal. Sealers can fill voids, lateral canals, and accessory canals where core obturation materials cannot infiltrate. If the sealer does not perform its function, microleakage may cause root canal failure via clinically undetectable passage of bacteria, fluids, molecules or ions between the tooth and restorative material. It has been reported that extrusion of the sealer during root canal filling has cytotoxic effects on periapical tissues, causing periapical inflammation, necrosis and pain. Endodontic sealers are categorized by composition based on setting reaction and composition: zinc oxide eugenol, salicylate, fatty acid, glass ionomer, silicone, epoxy resin, tricalcium silicate, and methacrylate resin sealer systems. Aslan &amp; Özkan (2021) reported on a trial that sought to evaluate the effect of two calcium silicate-based root canal sealers, Endoseal MTA and EndoSequence BC Sealer, on postoperative pain following single-visit root canal treatment on molar teeth compared to their epoxy/ amine resin-based counterpart AH Plus. The null hypotheses tested in this study were as follows:1. The type of sealer used would not change the incidence and the intensity of post-treatment endodontic pain2. The analgesic intake of patients following single-visit root canal treatment

Drug-Silica Coassembled Particles Improve Antimicrobial Properties of Endodontic Sealers

IntroductionThe purpose of this study was to assess the antimicrobial activity and flow of root canal sealers after incorporating novel highly loaded antimicrobial drug-silica coassembled particles (DSPs). MethodsDSPs were synthesized through coassembly of silica and octenidine dihydrochloride (OCT) antimicrobial surfactant. DSPs were loaded (1% and 2% wt) into epoxy resin sealer (AH Plus [AH]; Dentsply DeTrey GmbH, Konstanz, Germany) or calcium silicate–based sealer (EndoSequence Bioceramic Sealer (BC); Brasseler, Savannah, GA). OCT release from DSP-modified sealers was determined using liquid chromatography. Antimicrobial activity of sealers against planktonic or biofilm form Enterococcus faecalis was assessed using direct contact and membrane restricted tests. Sealer flow was tested according to ISO6876:2012. ResultsOCT release from BC + 1% or 2% DSPs was above the minimum inhibitory concentration following 2 days throughout the 30-day experiment, whereas OCT release from AH + 1% or 2% DSP was significantly below the minimum inhibitory concentration against E. faecalis (4 μg/mL) over the whole 30-day experimental period. All materials (with or without DSPs) killed planktonic bacteria initially. AH ± 1% or 2% DSPs had no antimicrobial activity after 7 days. BC + 1% or 2% DSPs maintained antibacterial activity over the 30-day period. Both modified and unmodified sealers completely inhibited the growth of E. faecalis biofilms after 24 hours of contact. DSPs decreased the flow of AH and BC sealers; for AH, the reduction was proportional to the amount of DSPs added. All modified and unmodified sealers, except for AH + 2% DSPs, were within the acceptable limits of ISO 6876 flow tests. ConclusionsDSPs enhanced the antimicrobial performance of BC but not AH, whereas the material’s flow remained compliant with ISO 6876 standards. Depending on the sealer, DSPs may enhance antimicrobial efficacy in root canal treatment and potentially improve treatment outcome.

Comparative evaluation of retreatability of bioceramic sealer (BioRoot RCS) and epoxy resin (AH Plus) sealer with two different retreatment files: An in vitro study.

Aim:The aim of the study was to evaluate and compare the retreatability of BioRoot RCS and AH Plus sealer with two different retreatment file systems using cone-beam computed tomography (CBCT) for assessing the filling remnants.Materials and Methods:A total of sixty mandibular premolars with single and oval root canals were prepared till size F3 and obturated with GP/AH Plus (Group 1) and GP/BioRoot RCS (Group 2). Canals were then retreated using two different retreatment file systems – ProTaper Universal Retreatment (PTUR) system and NeoEndo Retreatment system. The ability to re-establish working length (WL) and apical patency was recorded, and the percentage volume of residual filling material was evaluated using CBCT at the coronal, middle, and apical thirds. Data from the study were analyzed using one-way analysis of variance with Pearson's Chi-squared analysis and the Kruskal–Wallis test.Results:No statistically significant difference was found in the amount of residual sealer (AH Plus and BioRoot RCS) after retreatment throughout the whole study (P > 0.05) at various root canal levels. Furthermore, the BioRoot RCS group retreated with the PTUR system showed a higher frequency of failure in re-establishing WL and regaining apical patency than the other groups.Conclusion:Complete removal of root canal sealers could not be achieved regardless of the type of sealer used and the retreatment technique employed. Furthermore, in clinical settings, the retreatability of novel BioRoot RCS may be deemed feasible.

Effect of different final irrigation solutions on push-out bond strength of root canal filling material

Background: The adhesion of root canal filling material to dentin is one of the crucial factors in determining the success of endodontic treatment. However, the smear layer that forms during instrumentation serves as an interface that impedes the bonding mechanism of the filling material. A proper irrigation solution is required to remove the smear layer and provide a dentin surface that supports the bonding mechanism of the filling material in establishing good adhesion. Purpose: This study aims to evaluate and compare the bond strength of filling material with different final irrigation solutions. Methods: Mandibular premolars were prepared by a crown down, pressure-less technique and divided into three final irrigation groups (2.5% NaOCl, 17% EDTA and 20% citric acid). The root canal of each tooth was obturated using epoxy sealer and gutta-percha. A two-millimetre-thick section of the apical third portion of each group was arranged for the push-out assessment using a universal testing machine in an apical to coronal direction at 1 mm/min crosshead speed. Results: A one-way ANOVA test indicated the difference in push-out bond strength among the groups (p&lt;0.05). A post hoc Bonferroni test presented a statistically significant difference in the bond-strength value between the 2.5% NaOCl group compared with the 20% CA group (p&lt;0.05). Conclusion: The push-out bond strength of root canal filling material is increased by applying a chelating agent as the final irrigation solution where 20% of CA presents the highest push-out bond strength.

Comprehensive review of current endodontic sealers.

Endodontic sealers for non-surgical root canal treatment (NSRCT) span many compositions and attributes. This comprehensive review discusses current types of endodontic sealers by their setting reaction type, composition, and properties: zinc oxide-eugenol, salicylate, fatty acid, glass ionomer, silicone, epoxy resin, tricalcium silicate, and methacrylate resin sealers. Setting time, solubility, sealing ability, antimicrobial, biocompatibility, and cytotoxicity are all aspects key to the performance of endodontic sealers. Because sealing ability is so important to successful outcomes, the relative degree of microleakage among all the relevant sealers was calculated by way of a meta-analysis of relevant literature. Compared to AH Plus, tricalcium silicate sealers show the lowest relative microleakage among the sealers assessed, followed by silicone sealers and other non-AH Plus epoxy resin sealers. Tricalcium silicate sealers also exhibit the most favorable antimicrobial effect and excellent biocompatibility. Future sealers developed should ideally combine a hermetic seal with therapeutic effects.

The efficacy of different cleaning protocols for the sealer-contaminated access cavity.

Sealer remnants in the access cavity may negatively affect coronal seal and cause tooth discoloration. This study sought to evaluate the efficacy of different cleaning protocols for the sealer-contaminated access cavity. Sixty extracted human molars were accessed, chemomechanically prepared and warm vertically obturated with gutta-percha and epoxy resin sealer. Teeth were randomly assigned to one control (air/water spray) and five test groups (n = 10): scrubbing with an ethanol-saturated cotton pellet (CP), scrubbing with an ethanol-saturated microbrush (MB), air polishing (ProphyFlex, KaVo), MB + air polishing and cleaning with a round bur. Each tooth was split sagittally, and the sealer-covered access cavity area (SCA) before and after cleaning was determined using image analysis software and compared pre- and post-operatively and across groups using paired samples t test and one-way ANOVA. The SCA was significantly reduced in all test groups (P < 0.05), but not in the control group (P > 0.05). Highest epoxy resin sealer reductions were observed for MB (92%) and MB + air polishing (94%), yielding a significantly better SCA reduction than that of ethanol-saturated cotton pellet (58%), bur cleaning (69%) or air polishing alone (64%). All cleaning protocols except air/water spray reduced the amount of epoxy resin sealer in the access cavity, but none of them completely removed the sealer. Cleaning with the ethanol-saturated microbrush, with or without air polishing, performed better than the other methods. Scrubbing with an ethanol-saturated microbrush, with or without air polishing, was the most efficient method for cleaning the epoxy resin sealer-contaminated molar access cavity.

Apical sealing ability of chitosan nanoparticles in epoxy-resin-based endodontic sealer

A good sealing ability of apical part of root canal system is needed to prevent microleakage thus resulting long-lasting successful treatment. Chitosan nanoparticles as nanofillers could be added to epoxy resin sealer to increase adaptation to dentinal wall. The purpose of this study was to evaluate the apical sealing ability of chitosan nanoparticles addition to epoxy-resin-based sealer. Thirty mandibular premolars were used in this study. The root canals were prepared using rotary files up to #30/0.09. The canal was irrigated with 2.5% NaOCl and 17% EDTA, then was rinsed with sterile water. All teeth were randomly divided into 3 groups (n=10). Group I was obturated with gutta-percha, Group II was obturated with gutta-percha and epoxy resin sealer, group III was obturated with gutta-percha and epoxy resin sealer that was added with chitosan nanoparticles. All specimens were stored in an incubator for 7 days at 37 °C. After that, specimens were tested with centrifuging dye penetration method with methylene blue 2% solution. The specimens were longitudinally sectioned, observed under stereomicroscope (8x magnification) and measured in millimeters (mm). The data were analyzed using one-way Anova. The results of one-way Anova showed that dye penetration in apical part of the root canal in all groups was statistically significant difference. The addition of chitosan nanoparticles to epoxy resin sealer increases the apical sealing ability of root canal obturation material.

Apical Sealing Ability of Calcite-Synthesized Hydroxyapatite as a Filler of Epoxy Resin-Based Root Canal Sealer.

Background:The success of root canal treatment is influenced by hermetic root canal obturation. This study was conducted to analyze the apical sealing ability after the addition of calcite-synthesized hydroxyapatite (HA) as an epoxy resin sealer filler.Methods:Calcite-synthesized HA powder was prepared using the microwave hydrothermal process. HA resin sealer powder and epoxy resin paste (3:1) were mixed, and concentrations of 10%, 20%, 30%, 40%, and 50% were prepared. A sample of thirty maxillary incisors were prepared in the root canal and then, the crown was cut to leave 13 mm of the root and a working length of 12 mm. The root canal was prepared using the crown-down technique and irrigated using 2.5% sodium hypochlorite and 17% ethylenediaminetetraacetic acid alternately. The samples were divided into six groups, with each group consisting of five roots. Group I was obturated with gutta percha using an epoxy resin sealer without HA (HA-0%) as a control group. In each of the Groups II, III, IV, V, and VI, 10% HA resin sealer, 20% HA, 30% HA, 40% HA, and 50% HA were used. All the samples were incubated in a 10-ml simulated body fluid solution at 37°C for 4 weeks. Apical closure density measurement was done using a scanning electron microscope, and the results were analyzed using the Kruskal–Wallis and Mann–Whitney U-tests.Results:A significant increase in the apical sealing ability was observed in the HA-20% sealer group and the HA-30% and HA-40% groups compared to that in the control group. However, the HA-50% sealer group showed a decrease in the apical sealing ability, whereas the HA-10% sealer group showed no difference. The HA-30% had the highest sealing ability than other concentrations.Conclusion:The addition of calcite-synthesized HA as a filler at concentrations of 20%, 30%, and 40% increased the apical sealing ability of the epoxy resin sealer.

The antibacterial activity of an epoxy resin-based dental sealer containing bioactive glass, hydroxyapatite, and fluorohydroxyapatite nanoparticles against Enterococcus Faecalis and Streptococcus mitis

Objective(s): The present study aimed to investigate the antibacterial properties of a conventional epoxy-based dental sealer modified with synthesized bioactive glass (BG), hydroxyapatite (HA), and fluorine-substituted hydroxyapatite (FHA) nano-fillers. Materials and Methods: The synthesized nano-fillers were incorporated into the conventional epoxy-based dental seaer at the concentration of 10%. The antimicrobial properties of the unmodified sealers (controls) and modified seaers with BG, HA, and FHA nanoparticles (NPs) were evaluated based on biofilm formation and using the direct contact test (DCT) of Enterococcus faecalis and Streptococcus mitis. Data analysis was performed using one-way analysis of variance (ANOVA) and Tukey’s post-hoc test at the significance level of 5%. Results: A significant reduction was observed in the biofilm formation and DCT of the microbial strains in the three modified groups compared to the unmodified conventional epoxy sealer (P<0.05). The addition of FHA NPs resulted in the most significant antibacterial effects against E. faecalis and S. mitis, as well as a statistically significant reduction compared to the unmodified and BG-modified groups (P≤0.001). Conclusion: According to the results of this preliminary study, nano-structured FHA, HA, and BG fillers incorporated into epoxy-based dental sealers could be potentially effective biomaterials for antibacterial approaches to root canal treatments.

In-vitro bioactivity evaluation and physical properties of an epoxy-based dental sealer reinforced with synthesized fluorine-substituted hydroxyapatite, hydroxyapatite and bioactive glass nanofillers

The purpose of this study was to evaluate the physical properties and bioactivity potential of epoxy-based dental sealers modified with synthesized bioactive glass (BAG), hydroxyapatite (HA) and fluorine substituted hydroxyapatite (FHA) nanoparticles.The synthesized powders were incorporated at 10% and 20% into the epoxy-based dental sealer. The setting time, flow and solubility and microhardness of the modified and unmodified samples were examined. The bioactivity was evaluated using FESEM-EDX and elemental mapping, ATR-FTIR and XRD.The flow value of all of the experimental groups except the FHA modified samples, was greater than 20 mm. Concerning solubility, no specimens exhibited more than 1% weight loss. The solubility value of the FHA groups was statistically significant lower than other groups (p ≤ 0.001). The mean hardness values of all of the modified samples were significantly higher than the unmodified group (p ≤ 0.001).Regarding bioactivity, in vitro study revealed that after 3 days immersion in SBF a compact and continuous calcium phosphate layer formed on the surface of epoxy sealers containing BAG and HA nanoparticles.Based on these results, the addition of BAG and HA nanoparticles did not adversely alter the physical properties of epoxy sealers. Additionally, they improved the in vitro bioactivity of the epoxy sealer.

Incorporating N-acetylcysteine and tricalcium phosphate into epoxy resin-based sealer improved its biocompatibility and adhesiveness to radicular dentine

ObjectiveThis in vitro study was designed to evaluate the biocompatibility, adhesiveness, and antimicrobial activity of epoxy resin-based sealer associated with N-Acetylcysteine (NAC) or beta-tricalcium phosphate nanoparticles (β-TCP) as an experimental retro-filling material. MethodsCytotoxicity was assessed using 2,3-Bis-(Methoxy-4-Nitro-5-Sulphophenyl)-2H-Tetrazolium-5-Carboxanilide (XTT) and Sulforhodamine B (SRB) assays after exposing human periodontal ligament fibroblasts to extracts of the materials for 1, 3, or 7 days. For the adhesive resistance test, root canals (48 single-root teeth) were instrumented with Reciproc #40 files (VDW GmbH, Germany) and obturated. After 7 days, the apices were sectioned and a retrograde cavity prepared and filled with the experimental materials (Mineral trioxide aggregate, Epoxy sealer, Epoxy sealer+NAC, and Epoxy sealer+β-TCP). For the push-out test, one 2-mm thick slice was obtained from the apical third of each specimen. Antimicrobial activity was performed using agar diffusion method. Biofilms were grown in microplates and exposed to the extracts of retro-filled materials, followed by analysis of growth inhibition on agar plates. ResultsEpoxy sealer in association with β-TCP or NAC showed better bond strength while Mineral trioxide aggregate allowed for the lowest adhesion. Mineral trioxide aggregate, Epoxy sealer+β-TCP, and Epoxy sealer+NAC showed low cytotoxicity. Epoxy sealer was the most cytotoxic. In antimicrobial activity assays, all materials had no effect on Candida albicans. Addition of NAC improved the antimicrobial property of Epoxy sealer against Enterococcus faecalis compared to unmodified Epoxy sealer (P<0.05). SignificanceIncorporating β-TCP or NAC with Epoxy sealer could improve the adhesiveness and biocompatibility for better use in endodontic therapy.

Evaluation of Physicochemical Properties of a New Calcium Silicate–based Sealer, Bio-C Sealer

IntroductionCalcium silicate–based materials have been proposed as root canal sealers for root canal treatment. The aim of this study was to evaluate the physicochemical properties of a new calcium silicate–based sealer (Bio-C Sealer; Angelus, PR, Brazil) compared with a calcium silicate endodontic sealer (TotalFill BC Sealer; FKG Dentaire SA, La Chaux-de-Fonds, Switzerland) and an epoxy resin sealer (AH Plus; Dentsply DeTrey, Konstanz, Germany). MethodsThe setting time and flow were evaluated based on ISO 6876 standard. The pH value was evaluated after different time intervals of storage in deionized water (1, 7, 14, and 21 days). Radiopacity was evaluated by radiographic analysis in millimeters of aluminum. Solubility and volumetric change were evaluated after 30 days of immersion in distilled water. Solubility was assessed by mass loss (%), and volumetric change was evaluated by micro–computed tomographic imaging. The data were submitted to analysis of variance and Tukey statistical tests (P < .05). ResultsTotalFill BC Sealer and Bio-C Sealer were similar regarding radiopacity, volumetric change, and pH values (P > .05). Bio-C Sealer presented the shortest setting time and the highest flow and solubility (P < .05). AH Plus showed the highest radiopacity and the lowest flow, pH, solubility, and volumetric change (P < .05). ConclusionsBio-C Sealer showed a short setting time, alkalinization ability, and adequate flow and radiopacity as well as low volumetric change. However, this sealer had higher solubility than the rates required by ISO 6876 standard.

Esterases affect the physical properties of materials used to seal the endodontic space

Materials used to seal the endodontic space are subjected to enzymatic degradative activities of body fluids and bacteria. ObjectivesTo assess effects of simulated human salivary, blood and bacterial esterases (SHSE) on physical properties of typical restorative material and root canal sealers. MethodsSpecimens of set methacrylate-based resin composite (BisfilTM2B; RC), calcium-silicate sealer (EndoSequence®; BC) or epoxy-resin sealer (AH-Plus®; ER) were tested after up to 28Days exposure to phosphate buffered saline (PBS) or SHSE, using ANSI/ADA-57:2000 and ISO-6876:2012. ResultsRegardless of media, microhardness increased with time for BC remained unchanged for ER and decreased for RC (p < 0.05). SHSE moderated the increase for BC compared to PBS (28.0 ± 4.8 vs. 38.1 ± 7.9 KHN) at 7Days, and enhanced the decrease for RC at 7Days (55.6 ± 7.1 vs. 66.3 ± 6.5 KHN) and 28Days (52.3 ± 9.2 vs. 62.6 ± 8.5 KHN). Compressive strength was enhanced only for BC by either media. BC expanded with time for both incubation conditions; SHSE moderated the expansion compared to PBS at 7Days (0.026 ± 0.01% vs. 0.049 ± 0.007%). Shrinkage of ER was similar for both incubation media and was lower than that for RC (p < 0.05). Shrinkage of RC was enhanced by SHSE compared to PBS at 7Days (0.5 ± 0.07% vs. 0.38 ± 0.08%). Weight loss was lowest for ER and highest for BC (p < 0.05). It was enhanced by SHSE compared to PBS for BC at 28Days (2.40 ± 0.2 vs. 2.96 ± 0.19 W L%), and for RC at 7Days (0.54 ± 0.09 vs. 0.80 ± 0.1 W L%). SignificanceSimulated body fluids and bacterial esterases affected the physical properties of test materials, suggesting potential impacts on sealing ability and resistance to bacterial ingress, and tooth strength ultimately affecting their clinical performance.

Effect of a New Imidazolium-based Silver Nanoparticle Irrigant on the Bond Strength of Epoxy Resin Sealer to Root Canal Dentine.

The aim of this study was to evaluate the effect of a new imidazolium-based silver nanoparticle (ImSNP) root canal irrigant on the bond strength of AH-Plus sealer to root canal dentine. Forty single-rooted extracted human teeth were used in this study. The crowns were resected and according to the irrigation solutions used during root canal preparation, the roots were divided into 5 groups (n=8): Group 1: normal saline (control group), Group 2: 2.5% Sodium Hypochlorite (NaOCl), Group 3: 2.5% NaOCl+17% ethylene diamin tetracetic acid (EDTA), Group 4: silver nanoparticles (AgNPs), Group 5: AgNPs +17% EDTA. After root canal instrumentation, the canals were filled with AH-Plus. Then, after 7 days, 2 or 3 dentine disks were obtained from the mid-root of each sample. Bond strength was measured by the push-out test. Additionally, failure patterns were classified as adhesive, cohesive and mixed. Data were statistically analyzed by one-way ANOVA and Tamhane post hoc tests. The level of significance was set at 0.05. There was no statistically significant differences between groups (P>0.05). Groups 4 (AgNPs), 3 (2.5% NaOCl+17% EDTA) and 2 (2.5% NaOCl) showed statistically higher bond strength compared to group 1 (control group) (P<0.05). Also, Group 4 showed a significant difference with group 5 (AgNPs+17% EDTA) (P=0.017). The failure patterns were mainly cohesive. This in vitro study showed that, when used without EDTA, AgNPs improved the bond strength of AH-Plus to radicular dentine.

Antibiofilm activity of epoxy sealer incorporated with quaternary ammonium macromolecule

BackgroundA common reason for failure of root canal treatment is residual bacterial biofilm or reinfection due to coronal seal inadequacy. Recently, the idea of using macromolecules with antibacterial features has evolved. The addition of nanoparticle macromolecules to sealers gained antibiofilm properties as shown in several in vitro studies. Nevertheless, no technique has yet been able to completely eliminate the residual biofilm. We evaluated the in vitro antibacterial effect of epoxy sealer, BJM ROOT CANAL SEALER® (BJM Laboratories Ltd., Or-Yehuda, Israel), incorporated with non-nanoparticle quaternary ammonium macromolecule (BIOSAFE HM4100, Pittsburg, PA, USA) against existing biofilm of Enterococcus faecalis and its ability to inhibit it de-novo.MethodsSix mm diameter discs of epoxy sealer (BJM) incorporated with various concentrations of immobilized ammonium particles (0, 0.4, 0.8, 1.6, and 3.3% w/v) were tested for its antibacterial effect on de-novo biofilm formation (by Biofilm Formation assay), and on existing biofilm (by Biofilm Viability assay). The Live/Dead bacterial ratio was determined using fluorescence microscopy.ResultsBiofilm formation assay showed significant reductions in de-novo biofilm formation of 25 and 72% in the higher ammonium particle concentrations of 1.6 and 3.3% w/v respectively (p < 0.001 for both). Biofilm viability assay showed significant reductions in existing biofilm viability of 20 and 36% in the higher ammonium particle concentrations of 1.6 and 3.3% w/v respectively (p < 0.001 for both).ConclusionsBiosafe incorporated in epoxy root canal sealer discs showed a pronounced reduction of de-novo biofilm formation in the higher concentrations (1.6 and 3.3% w/v), as well as some antibacterial effect against existing biofilm of E. faecalis. This sealer may be effective for prevention of de-novo formation of bacterial biofilm in treated root canals.

Comparative Evaluation of Physicochemical Properties and Apical Sealing Ability of a Resin Sealer Modified with Pachymic Acid.

Objective:The addition of pachymic acid (PA) to AH Plus (an epoxy resin sealer) offsets the cytotoxicity of the latter. Prior to the clinical implementation of this formulation, a thorough knowledge of its physicochemical properties and sealing ability becomes mandatory. Hence, this in vitro study aimed to characterize and evaluate the physicochemical properties and apical sealing ability of AH Plus (AHP) with and without the addition of PA.Methods:Flow, setting time, film thickness, solubility and radiopacity of AHP (group 1) and AHP modified with PA (AHP/PA, group 2) were evaluated in accordance with the guidelines put forth by ISO 6876:2012. The percentage was determined under each parameter. Apical sealing ability was assessed using fluid filtration device. An independent samples t-test was used for inter- and intra-group comparisons of mean fluid flow (MFF).Results:Incorporating PA to AHP decreased its flow, setting time and film thickness by 24.34%, 2.14% and 31.71% respectively. The solubility of group 2 increased on day 1 by 85.71% and decreased on days 3, 7 and 14 by 46.67%, 34.79% and 13.8% respectively. The radiopacity of AHP was not altered by the addition of PA. MFF rates of group 2 was significantly higher than group 1 on day 1, but not significantly different on day 7.Conclusion:AHP/PA exhibited physicochemical properties that were within the requirements of ISO and with time, and showed fluid flow similar to AHP.