Evaluation of Dentinal Tubule Penetration after the Use of Dentin Bonding Agent as a Root Canal Sealer

Comparative Evaluation of Apical Leakage in Root Canal Obturation Using AH Plus Sealer, Bioceramic Sealer, and Bioceramic Sealer Incorporated With Chitosan Nanoparticles: An In Vitro Study

Introduction Endodontic re-infections primarily occur due to the ingress of bacteria and their toxins through an incomplete seal following obturation. A variety of sealers have been developed to achieve effective integration with the different obturation materials and dentinal tubules. To choose the right endodontic sealer and application for each clinical instance, one must be aware of the attributes of the various sealers commonly used in clinical practice. The utility of chitosan nanoparticles in endodontics requires exploration to understand the faring of this material in comparison to the existing gold standards. This study aims to compare the apical leakage after obturation using AH Plus sealer and bioceramic sealer with and without chitosan nanoparticles. Materials and methods Forty single-rooted, single-canal extracted teeth were selected and decoronated to standardize the root length to 14 mm. Root canals were prepared using Protaper rotary files and irrigated with sodium hypochlorite, EDTA (ethylenediaminetetraacetic acid), and saline. The samples were randomly divided into four groups (n=10): group I (gutta percha), group II (gutta percha + AH Plus sealer), group III (gutta percha + bioceramic sealer), and group IV (gutta percha + chitosan nanoparticles in bioceramic sealer). The sealers were applied, and obturation was performed using the cold lateral condensation technique. Post-obturation, the samples were sealed with Cavit-G, coated with nail varnish, and immersed in 2% methylene blue dye for 72 hours. The teeth were then sectioned longitudinally and inspected for dye penetration using a stereomicroscope. Results The mean dye penetration values were as follows: 4.77 ± 2.08 mm in group I, 2.93 ± 0.40 mm in group II, 2.34 ± 1.46 mm in group III, and 1.93 ± 1.68 mm in group IV. Statistical analysis using one-way ANOVA showed significant differences (p < 0.05) between the groups. Tukey's post hoc test revealed the least microleakage in group IV, indicating superior sealing ability of bioceramic sealer with chitosan nanoparticles. Conclusion Incorporation of chitosan nanoparticles in bioceramic sealer significantly enhances its sealing ability, reducing apical microleakage more effectively than gutta percha (2.5 times), AH Plus sealer (1.5 times), and bioceramic sealer alone (1.2 times). This suggests that chitosan nanoparticles could be a promising addition to endodontic sealers to improve treatment outcomes.

Analysis of the adhesive interface of dentine treated with carbodiimide and chitosan before cementation of fiberglass posts with different resin cements

The objective of this study is to evaluate the effect of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and chitosan (CHI) on the adhesive interface of resin cements to root dentine. Forty-five upper canines were sectioned, endodontically treated, prepared and divided into three groups according to dentine treatment (distilled water-DW, CHI 0.2% and EDC 0.5) and in three subgroups according to resin cement: RelyX ARC, Panavia F 2.0 or RelyX U200. Slices were obtained, with five slices of each third submitted to the analysis of the adaptation of the adhesive interface through scores and the perimeter with gaps in confocal laser scanning microscopy and one slice of each third later evaluated qualitatively in scanning electron microscopy. The results were analyzed using with Kruskal-Wallis and Spearman correlation tests. There was no difference in adaptation for the different resin cements (p = .438). EDC presented better adaptation when compared to the groups treated with DW and CHI (p < .001), while the CHI and DW presented similar adaptation values (p = .365). No difference was observed in the perimeter referring to the gap areas for the different resin cements (p = .510). EDC showed a lower percentage of perimeters with gaps when compared to CHI (p < .001), with the percentage of perimeter with gaps of teeth treated with CHI being lower than DW (p < .001). A positive correlation coefficient equal to 0.763 was obtained between the perimeter with gaps and the adaptation data of the adhesive interface (p < .001). EDC resulted in better adaptation of the adhesive interface and a lower percentage of perimeters with gaps compared to chitosan.

A Novel Polyurethane Expandable Root Canal Sealer

INTRODUCTION

Endodontic sealers play a vital role in the obturation of root canal space. The aim of this study was to evaluate the utility of a recently developed polyurethane expandable sealer (PES), along with its cytotoxicity and dimensional changes.

METHODS

L929 fibroblasts and an cell viability assay (MTS assay) were used to determine the cytotoxicity of dental sealers (AH Plus [Dentsply Maillefer, Ballaigues, Switzerland], Sure-Seal Root [Sure Dent Corporation, Gyeonggi-do, South Korea], and the PES) at 24, 48, 72, and 96 hours. An advanced choroidal neovascularization model was used to assess the effect of these sealers on angiogenesis. Thirty-six extracted single-rooted human teeth were prepared and randomly divided into 3 groups (n = 12). Obturation was performed with gutta-percha and a sealer using lateral compaction as follows: group 1, AH Plus; group 2, Sure-Seal; and group 3, PES. The average depth of sealer penetration into dentinal tubules was measured with a scanning electron microscope. Data were analyzed using 1-way analysis of variance and post hoc Tukey tests (level of significance, P < .05).

RESULTS

The values of MTS, choroidal neovascularization, and the penetration depth of PES were significantly higher than in other experimental groups (P < .05). The lowest values were noted in specimens of AH Plus, whereas the highest were detected in the PES group.

CONCLUSIONS

PES showed promising results in terms of biocompatibility and dentinal tubule adaptation and penetration.

Comparison of dentin penetration ability of different root canal sealers used with different obturation methods

This in vitro study aimed to investigate the tubular penetration depth of four different sealers used with two different obturation methods in the apical, middle, and coronal root canal dentin. Eighty-four single-rooted teeth were instrumented until the F4 ProTaper universal rotary file and filled with AH26, AH Plus (Dentsply, DeTrey, Konstanz, Germany), RealSeal (SybronEndo, Orange, CA), and MTA Fillapex (Angelus, Londrina, Brazil) using cold lateral condensation (CLC) and single-cone (SC) obturation techniques. Thereafter, the roots were sectioned longitudinal and prepared for scanning electron microscope evaluation. The maximum and minimum sealers penetration depth into dentinal tubules at the apical, middle, and coronal regions and the average depth of sealer penetration were calculated. The data was statistically analyzed two-way ANOVA and post hoc Tukey and Dunnett tests and independent samples t test using maximum mean values. There was no statistically difference between the obturation methods (p > .05). When the sealers are evaluated within themselves AH26 was affected by obturation methods significantly (p < .05). Also the results revealed a significant difference between root regions (p < .05). AH26 and RealSeal root canal sealers had the highest penetration values with CLC and SC obturation techniques, respectively. The obturation method did not affect the penetration amount of root canal sealers. RealSeal root canal sealer performed better penetration ability than the other sealers. Apical third of the root in all groups showed lowest penetration depth.

Evaluation of Dentin Adaptability of Fluoride Varnish as a Root Canal Sealer Using Scanning Electron Microscopy

Objectives:

This study aimed to assess the dentin adaptability of a certain type of fluoride varnish, as a novel root canal sealer, in comparison with AH-Plus sealer.

Materials and Methods:

Twenty-four extracted single-rooted, single-canal human permanent teeth with straight and fully formed roots and no internal calcification, resorption or cracks, were selected and decoronated such that the remaining root length was 14 mm in all teeth. Root canals were prepared using the Mtwo rotary file system according to the manufacturer’s instructions and filled with gutta-percha and either AH-Plus (n=12) or fluoride varnish (n=12) via the lateral compaction technique. Each root was then sectioned at 4 and 8 mm distances from the apex for evaluation under a scanning electron microscope (SEM). The gap size between the sealer and dentin was measured. Statistical analysis was performed using the Kolmogorov-Smirnov test and t-test with the significance level set at 0.05.

Results:

The mean gap size was 14.407±1.402 μm and 8.342±0.694 μm in the roots obturated with AH-Plus and fluoride varnish sealers, respectively. The t-test revealed a statistically significant difference (P<0.001) in this regard between the two groups.

Conclusion:

Fluoride varnish, as a root canal sealer, has a superior adaptation to dentinal canal walls compared to the AH-Plus sealer.

The effects of pressure in vitro on three methods of root canal obturation

INTRODUCTION

The seal of root canal fillings depends on the anatomy of the root canal system and on the properties of filling materials and their bond to the walls of the root canal. Alterations in pressure may influence these properties. The current study investigated and compared microleakage in a tapered single-cone method versus lateral and vertical condensation after diving simulation.

METHODS

One hundred and thirty five extracted single-rooted teeth were used. Following instrumentation and irrigation to #30.06 Mtwo rotary system, obturations were performed in three groups of 45 teeth: Group 1, tapered single-cone with Endoseal MTA sealer; Group 2, lateral condensation with AH26 sealer; Group 3, vertical condensation with AH26 sealer. Then all specimens were divided into three groups and incubated at ambient room pressure (101.3 kPa), 203 kPa or 304 kPa for 120 minutes respectively 20 times over one month to simulate diving conditions. Microleakage quantitative analysis was recorded by using a 2% Methylene blue dye for 24 hours.

RESULTS

The amounts of microleakage increased with increasing pressure in all obturation groups; however, the differences were not statistically significant (P > 0.05). At all three pressures, the least microleakage was recorded in Group 3, vertical condensation. Although the differences between vertical condensation, lateral condensation, and tapered single-cone methods were statistically significant (P < 0.001), the vertical condensation and lateral condensation groups did not differ from each other (P > 0.05).

CONCLUSIONS

Vertical condensation may be the best technique, based on sealing ability, for people who frequently experience pressure alterations.

Effect of the smear layer on apical seals produced by two calcium silicate-based endodontic sealers

We compared the apical seals of two new calcium silicate-based sealers (iRoot SP and MTA Fillapex) in the presence and absence of a smear layer. Eighty-two human premolars were prepared and randomly divided into four groups. In groups 1 and 3, the smear layer was retained. In groups 2 and 4, the root canals were irrigated with EDTA to remove the smear layer. Canals were filled using gutta-percha/iRoot SP (in groups 1 and 2) or obturated with gutta-percha/MTA Fillapex (in groups 3 and 4). Fluid filtration was used to evaluate apical microleakage. The presence of the smear layer had no significant effect on the sealing properties of the filling materials, except for iRoot SP at 2 weeks (P = 0.007). There was significantly less microleakage with iRoot SP than with MTA Fillapex (P = 0.025 at 2 weeks; P < 0.001 at 3 months). Leakage decreased significantly over time in all specimens, except in group 2 (P = 0.473). In conclusion, removal of the smear layer had no adverse effect on the sealing properties of calcium silicate-based sealers. In addition, the sealing ability of iRoot SP was superior to that of MTA Fillapex.

Evaluation of Apical Micro-leakage of Different Endodontic Sealers in the Presence and Absence of Moisture

Background and aims. With availability of hydrophilic sealers, drying of the canals before endodontic obturation is still a matter of debate. The aim of this study was to compare the apical micro-leakage of AH26, Excite DSC, MTA Fillapex, and ZOE sealers in dry and moist root canals.

Materials and methods. This experimental study was performed on 90 extracted maxillary central incisors. Rotary files were used for preparation of the canals. Root canals were filled with a single gutta percha cone, using one of the four sealers, under dry and moist root canal conditions (10 teeth in each group). Orifices were sealed with glue wax and all root surfaces were covered with nail polish except the positive control group. After ten days in 100% humidity, teeth were placed in methylene blue, and then were cut in longitudinal axis. Blue color permeability was measured by stereomicroscope in micrometers. Data were analyzed by t-test, ANOVA and Scheffe post hoc test using SPSS V.18 software at P < 0.05.

Results. Mean apical micro-leakage was significantly lower in the dry groups (P < 0.001). Minimum and maximum micro-leakage was seen in AH26 and ZOE, respectively. MTA Fillapex did not exhibit a significant difference in apical micro-leakage between dry and moist conditions (P > 0.05). Apical micro-leakage was significantly higher in the Excite DSC groups (P < 0.001).

Conclusion. AH26 provided the least apical micro-leakage under dry conditions while ZOE had the highest micro-leakage under moist conditions. MTA Fillapex provided acceptable apical seal regardless of moisture.

Adhesive interface and bond strength of endodontic sealers to root canal dentine after immersion in phosphate-buffered saline

This study evaluated the bond strength (BS) and the adhesive interface of four endodontic sealers to root canal dentine, before, and after immersion in phosphate buffered saline (PBS) to simulate an in vivo environment. Eighty roots were instrumented using ProTaper rotatory files, under irrigation with 17% EDTA and 1% NaOCl. Posteriorly were divided into four groups (n = 20) according to the sealer used: Endofill, AH Plus, Sealapex, and MTA Fillapex. Each group was divided into two subgroups (n = 10) and stored at 37°C immersed in water for 7 days and in PBS for 60 days. From each subgroup, 1 mm thick sections were obtained. One section of each region (coronal, middle, and apical) was submitted to the push-out test and failures were observed. Twelve sections of each subgroup (four from each region) were evaluated under SEM. Three-way ANOVA evaluation for BS showed significant differences between groups and regions (P < 0.0001), but not between subgroups (P > 0.05). AH Plus had significantly higher BS than the others sealers, regardless of the analyzed subgroup (Tukey's test, P < 0.5). The most common failures were adhesive to dentine and cohesive of the sealer. The SEM evaluation (Kruskal-Wallis, Mann-Whitney) showed homogeneous adhesive interface formed and sealer tags in all groups with significant statistical differences with AH Plus, regardless of PBS immersion. AH Plus was superior to the other sealers for both BS and quality of interface formation. Immersion in PBS did not interfere on BS or adhesive interface of the sealers tested.

Scanning electron microscopic evaluation of dentinal tubule penetration of Epiphany in severely curved root canals

Objective:

The purpose of this study was to compare the depth of dentinal tubule sealer penetration in the apical thirds of severely curved root canals obturated with Resilon/Epiphany self-etch (SE) or gutta-percha/AH Plus using scanning electron microscopy.

Materials and Methods:

A total of 34 extracted human mandibular molars with 25-40° curvature of the mesial root canal were selected for this study. After preparation, the mesiobuccal canals were randomly obturated with gutta-percha and AH Plus sealer or Resilon and Epiphany SE sealer. Sealer penetration was evaluated in 2 mm sections of the apical thirds of roots using scanning electron microscopy. Data were analyzed using the independent t-test and Mann-Whitney U-test, with significance set at P < 0.05.

Results:

Mean tubular penetration depth did not differ significantly between Resilon SE (172.22 μm) and AH Plus (122.18 μm; P > 0.05). The density of sealer tags in the apical thirds of root canals was also equivalent (P > 0.05).

Conclusion:

Average penetration into dentinal tubules in the apical thirds of severely curved roots did not differ significantly between Epiphany SE and AH Plus.

Bond strength to radicular dentin and sealing ability of AH Plus in combination with a bonding agent

OBJECTIVE

To evaluate the sealing ability and bond strength of AH Plus sealer associated with the hybridization protocol of radicular dentin with Scotchbond Multi Purpose (SB).

MATERIALS AND METHODS

Ninety palatal roots of maxillary molars were selected and divided into three groups (n = 30) according to filling protocol (G1, AH Plus/Resilon; G2, SB/AH Plus/Resilon; and G3, AH Plus/Gutta-Percha). In groups in which AH Plus + resin cones were used, dentin was hybridized before applying sealing material. For the bond strength test, 60 roots of bovine teeth were selected. Six holes were made in each root, two in the cervical, middle and apical third of the root. The roles were filled with AH Plus sealer with or without an adhesive system and submitted to push out test and the fracture mode was examined using a stereomicroscope (×32).

RESULTS

Statistical analysis showed that ScotchBond Multi Purpose (SB) + Resilon cone + AH Plus group promoted higher sealing ability than the gutta-percha + AH Plus group (p < 0.05). Bond strength was lower with SB application than without it (p < 0.05). A reverse correlation was found between bond strength and sealing ability. The fracture mode methodology revealed 22.77% of adhesive, 11.67% of cohesive and 65.55% of mixture fractures for SBMP/AH Plus protocol, whereas the AH Plus protocol indicated 86.11% of cohesive and 13.89% of mixed fractures.

CONCLUSION

It was concluded that the use of the adhesive system Scotchbond Multi Purpose improved coronal sealing ability of AH Plus, but bond strength of sealer was reduced when adhesive was applied.

In vitro Enterococcus faecalis biofilm formation on five adhesive systems

Objective: To determine the E. faecalis biofilm formation on the surface of five adhesive systems (AS) and its relationship with roughness. Study Design: The formation of E. faecalis biofilms was tested on the surface of four dual-cure AS: AdheSE DC, Clearfil DC Bond, Futurabond DC and Excite DSC and one light-cure antimicrobial AS, Clearfil Protect Bond, after 24 hours of incubation, using the MBEC high-throughput device. Results: E. faecalis biofilms grew on all the adhesives. The least growth of biofilm was on Excite DSC, Clearfil Protect Bond, and the control. Futurabond DC resulted in the greatest roughness and biofilm amount. There was a close relationship between the quantity of biofilm and roughness, except for Clearfil Protect Bond, which showed little biofilm but high roughness. Conclusion: None of the tested AS prevented E. faecalis biofilm formation, although the least quantity was found on the surface of Clearfil Protect Bond.

Key words:Adhesive systems, biofilm, Enterococcus faecalis, roughness.