Physical Properties and Chemical Characterization of Two Experimental Epoxy Resin Root Canal Sealers

Comparison of the Physical Properties of Three Resin-Based Root Canal Sealers: An In-Vitro Study

Objectives: This in-vitro study aimed to evaluate the physical properties of three resin-based root canal sealers, including BETA-RCS, AH26, and Adseal. Materials and Methods: Flowability, film-thickness, solubility, and radiopacity of BETA-RCS, AH26, and Adseal sealers were evaluated according to ISO 6876/2012 specifications. Three samples of each sealer were used to test each of the properties. Results: The results revealed that the flow rate (mm) of BETA-RCS, Adseal, and AH26 were 23.06±1.58, 22.5±4.23, and 21.85±1.71, respectively. Film-thickness values (µm) for BETA-RCS, Adseal, and AH26 sealers were 52.33±2.51, 18.66±0.57, and 52±2, respectively. No significant difference was observed regarding film-thickness between AH26 and BETA-RCS (P>0.05), while Adseal showed significantly lower film-thickness (P˂0.05). The highest and lowest solubility were related to BETA-RCS and Adseal, respectively. However, all sealers had acceptable solubility and radiopacity. Conclusion: The findings of the current study suggested that all three root canal sealers including BETA-RCS, AH26, and Adseal had similar properties based on ISO 6876 standard criteria. As such, they could be viable choices for facilitating effective root canal procedures. Further long-term clinical studies are warranted to assess their performance and success rates in actual endodontic cases.

Biocompatibility of an experimental endodontic sealer (Resil) in comparison with AH26 and AH-Plus in rats: An animal study

Background. This experimental study sought to assess the biocompatibility of Resil, an experimental epoxy resin-based sealer, in comparison with AH26 and AH-Plus sealers in rats. Methods. Twelve male Wistar rats weighing 400 to 500 grams were evaluated in this experimental study. Four polyethylene tubes containing Resil, AH-Plus, AH26 sealers, and an empty tube were implanted subcutaneously in rats. The degree of inflammation, type of inflammatory cells present, foreign body reaction, quality of connective tissue, and presence of fibrotic capsule were evaluated histopathologically at 7 and 30 days after implanting the tubes to assess the biocompatibility of sealers. Data were analyzed using the Chi-square test. Results. At 7 days, the degree of inflammation in Resil group was almost similar to AH26 group, and 66.7% of rats showed moderate inflammation. AH-Plus group showed less inflammation than Resil and AH26 (50% of rats showed low degree of inflammation), At 30 days, the inflammatory status of all groups was the same, and 83.3% of rats showed very low degree of inflammation. The inflammatory response during the experiment decreased from day 7 to day 30 in all groups. The neutrophil count (P=0.00), fibrotic capsule (P=0.01) and the amount of granulation tissue (P=0.05) significantly decreased from day 7 to day 30 in Resil group. Conclusion. Resil sealer showed appropriate biocompatibility at 7 and 30 days after subcutaneous implantation in rats, comparable to AH26 and AH-Plus. Clinical studies are required to confirm these results.

Evaluation of Chemical and Physical Properties of an Experimental Endodontic Sealer in Comparison with AH-26 and AH-Plus

Introduction

This study aimed to assess the physical and chemical properties of an experimental endodontic resin sealer (Resil) compared with AH-26 and AH-Plus.

Methods and Materials

In this in vitro experimental study, dimensional stability (by measurement of length; n=5), pH (using a pH meter; n=5), and antibacterial activity (by agar diffusion test; n=8) of Resil, AH-26 and AH-Plus were evaluated and compared using one-way ANOVA and Tukey's test.

Results

All three groups showed significant expansion from day 1 to day 30 (P<0.05). The difference in the mean dimensional changes between the AH-Plus and experimental sealer was significant (P=0.020). Two hours after mixing, the pH of experimental sealer (Resil) was significantly lower than that of AH-Plus (P<0.001) and higher than that of AH-26 (P<0.001). Antibacterial activity of the experimental sealer before and after setting was significantly higher than that of the other two sealers (P<0.001).

Conclusion

The results of this in vitro study showed that the experimental sealer had greater 1 to 30 days dimensional changes than the other two sealers. It had an alkaline pH, and showed superior antibacterial activity compared with AH-26 and AH-Plus. It may be possible to use this sealer in the clinic after animal studies because an epoxy resin based sealer with lower price and more appropriate properties is favorable.

Endodontic Sealers Modified with Silver Vanadate: Antibacterial, Compositional, and Setting Time Evaluation

The incorporation of nanoparticles into endodontic sealers aims at increasing antimicrobial activity of the original material. Aim. The aim of this study is to incorporate the nanostructured silver vanadate decorated with silver nanoparticles (AgVO3, at 2.5%, 5%, and 10%) into three endodontic sealers and evaluate the antibacterial activity of freshly sealers, surface topography and chemical composition, and setting time. Material and Methods. The AgVO3 was incorporated into AH Plus, Sealer 26, and Endomethasone N at concentrations 0%, 2.5%, 5%, and 10% (in mass). The antibacterial activity of freshly sealers was assessed by direct contact with Enterococcus faecalis and CFU/mL count (n=10), surface topography, and chemical composition were measured by SEM/EDS, and the setting time was measured by Gillmore needle (n=10). The Kruskal-Wallis and Dunn statistical tests were applied (α=0.05). Results. All groups of sealers evaluated inhibited E. faecalis (p>0.05). The incorporation of AgVO3 altered the atomic proportions between components of the endodontic sealers, and the percentage of silver (Ag) and vanadium (V) increased proportionally to the concentrations of AgVO3. Topography analysis showed differences in components distribution on the surface of the specimens. The sealers incorporated with AgVO3 of AH Plus presented a lower setting time than the control group (p<0.05). For Sealer 26 and Endomethasone N, the incorporation of AgVO3 increased the setting time in relation to control group (p<0.05). Conclusions. The modification of endodontic sealers by AgVO3 increased the atomic percentage of Ag and V proportionally to the concentration of the nanomaterial and changed the atomic percentage of the sealer components and setting times. It cannot be affirmed that the AgVO3 promote differences in the antimicrobial activity of freshly sealers, and further investigations of the antimicrobial activity of the set sealers should be carried out.

Influence of Adding Nanoparticles of Silver Vanadate on Antibacterial Effect and Physicochemical Properties of Endodontic Sealers

Introduction

The aim of this study was adding the nanostructured silver vanadate decorated with silver nanoparticles (AgVO₃) (0, 2.5, 5, and 10%) to the endodontic sealers AH-Plus, Sealer 26 and Endomethasone N, and evaluate the antimicrobial activity, solubility and pH.

Methods and Materials

The antimicrobial activity of freshly mixed sealers (n=10) and set sealers (n=9) against Enterococcus faecalis (E. faecalis) was evaluated by colony forming units per milliliter and epifluorescence microscopy. Solubility (n=9) and pH (n=10), 6 and 24 h and 7, 14, and 30 days were also evaluated. The Kruskal-Wallis and Dunn's post-test were applied for the antimicrobial activity of fresh sealers. ANOVA and Tukey's post-test was used for set sealers and solubility, and Friedman's two-way analysis of variance for pH (α=0.05).

Results

The fresh sealers inhibited E. faecalis. Set Sealer 26 (5 and 10% AgVO₃) and Endomethasone N (2.5, 5, and 10% AgVO₃) presented higher activity then the corresponding controls. Modification with AgVO₃ did not influence the solubility of AH Plus and Sealer 26, but Endomethasone N (5%) presented reduced solubility. The AH-Plus groups showed acidic pH, and Sealer 26, basic pH after 30 days. Endomethasone N (5 and 10% AgVO₃) presented statistical difference compared to 0% (P<0.05).

Conclusion

In this in vitro study all fresh sealers and set Sealer 26 (5 and 10%) and Endomethasone N (2.5, 5, and 10%) presented higher antimicrobial activity than controls. The modification with 5% and 10% AgVO₃ decreased solubility and pH of Endomethasone N, but did not affect the other groups.

Evaluation of Selective Physicochemical and Biological Properties of Different Root Canal Sealers

Introduction

This in vitro study aimed to evaluate the chemical composition, water solubility, radiopacity, pH, electrical conductivity and cytotoxicity of four different root canal sealers.

Methods and Materials

Four materials were tested including an epoxy resin-based sealer (AH-Plus), a calcium silicate-based sealer (MTA Fillapex), a calcium hydroxide-based sealer (Sealapex) and a zinc-oxide-eugenol-based sealer (Endofill). The materials were submitted to energy-dispersive x-ray microanalysis for elemental chemical composition. Solubility and radiopacity were evaluated according to ANSI/ADA. The pH and electrical conductivity were measured at different periods of time. L929 immortalized mouse fibroblast line were used for cytotoxicity evaluation. Statistical analyses were carried out using the ANOVA and Tukey's test.

Results

The main elements were found to be silicon and calcium in MTA Fillapex, calcium and bismuth in Sealapex, zirconium and tungsten in AH-Plus and zinc and bismuth in Endofill. Sealapex had the highest value for solubility (P<0.05), AH-Plus showed the highest radiopacity value (P<0.05) while MTA Fillapex had the highest pH and electrical conductivity values (P<0.05). AH-Plus showed the highest rate of cell viability (P<0.05).

Conclusion

Based on the results of this in vitro study, it was possible to conclude that Endofill and Sealpex did not meet the requirements for water solubility. The tested sealers were alkaline and showed radiopacity in accordance with ANSI/ADA standards. AH-Plus showed to be less cytotoxic than other tested root canal sealers.

Physical Properties, Cytocompatibility and Sealability of HealApex (a Novel Premixed Biosealer)

Introduction:

The objective of this study was to evaluate the physical properties, cytotoxicity and sealing ability of HealApex _a new premixed calcium-silicate-phosphate-based biosealer_ in comparison with AH-26.

Methods and Materials:

Setting time, working time, film thickness, flow and radiopacity evaluation were performed according to ISO 6876 specification. L929 fibroblasts were incubated with the extracts of sealers and cytotoxicity was then evaluated using MTT assay. Thirty intact extracted human premolars were instrumented using step-back technique. The specimens were obturated with gutta-percha and experimental sealers employing lateral condensation technique. Sealing ability of sealers was investigated for up to one month using fluid filtration method. Data were statistically analyzed by t-test and ANOVA.

Results:

Physical properties of both sealers conformed to ISO specification. AH-26 exhibited significantly higher flow, higher radiopacity and lower film thickness; whereas HealApex showed lower setting time (P<0.05). HealApex represented high cell viability (P<0.05); however, AH-26 demonstrated significantly lower cell viability compared with the negative control group (P<0.05). There was no significant difference in microleakage between the sealers after 1 and 7 days; however, after 30 days, HealApex displayed better sealing ability (P<0.05).

Conclusions:

In this in vitro study, HealApex revealed acceptable physical properties, biocompatibility and good sealing ability as an endodontic sealer. Obtained results showed the new sealer had acceptable physical properties and good biocompatibility. In short term, the sealing ability of HealApex was comparable with AH-26 whilst in long term, HealApex’s sealing ability was better than the epoxy resin-based sealer.

Cytotoxicity of Two Experimental Epoxy Resin-Based Sealers

INTRODUCTION

Many endodontic sealers are available, but search for the ideal sealer continues. This study aimed to assess the cytotoxicity of two experimental endodontic sealers in comparison with AH-26 resin sealer.

METHODS AND MATERIALS

This in vitro study was conducted on conventional and experimental root canal sealers: AH-26, an epoxy resin experimental sealer A (ES-A) composed of calcium tungstate, zirconium oxide, aerosil, bismuth oxide, titanium oxide, hexamine and an epoxy resin and experimental sealer B (ES-B) with compositions similar to ES-A except for the presence of imidazoline as a catalyst. The experimental sealers containing nano-particles were mixed with 37.5% of an epoxy resin. The extraction of five samples of each experimental sealer (A, B) and AH-26 sealer were subjected to MTT assay in the form of set and fresh at 1, 24 and 72 h with 1, 10, 100% dilution according to the International Standard ISO:10993-2012. Data were analyzed using the one-way ANOVA.

RESULTS

The set ES-A had the least cytotoxicity from the first hour but the cytotoxicity of ES-B and AH-26 extraction decreased over time. In fresh form, except for 100% concentration, ES-A showed the least cytotoxicity compared to the other two sealers.

CONCLUSION

All three sealers had high cytotoxicity in 100% concentration but had low cytotoxicity in 10% and 1% concentrations.