A comparative evaluation of smear layer removal by using edta, etidronic acid, and maleic acid as root canal irrigants: An in vitro scanning electron microscopic study

Impact of different disinfection protocols on the bond strength of NeoMTA 2 bioceramic sealer used as a root canal apical plug (in vitro study)

INTRODUCTION

Treatment of an immature permanent tooth required a special disinfection protocol due to the presence of thin radicular walls, which are prone to fracture. Mineral Trioxide Aggregate (MTA) has been proposed as a root repair material for root canal treatment. The aim of this in vitro study was to compare the push-out bond strength of conventional White MTA cements and second generation NeoMTA 2 in imitated immature roots treated with different disinfection protocols, which are 5.25% sodium hypochlorite (NaOCl), followed by 17% ethylenediaminetetraacetic acid (EDTA), and NaOCl, followed by 20% etidronic acid (HEBP).

METHODS

The root canals of freshly extracted single-root teeth were manually prepared until 90 K-file to imitate immature roots. Roots were randomly divided into four groups (G) according to the disinfection protocol (n = 15 per group). where G1 (NaOCl + EDTA + White MTA) and G2 (NaOCl + EDTA + NeoMTA 2) While G3 (NaOCl + HEBP + White MTA) and G4 (NaOCl + HEBP + NeoMTA 2) All groups were activated with manual agitation. All specimens were incubated for 48 h. The apical third of each root was perpendicularly sectioned to attain a slice of 3 mm thickness. Push-out bond strength values were assessed using a two-way ANOVA and a Student's t test.

RESULTS

G3 and G4 that were treated with HEPB showed higher significant push-out bond strength mean values than G1 and G2 treated with an EDTA chelating agent. Irrespective of the chelating agent used, it was found that both NeoMTA 2 and White MTA had no significant influence on push-out bond strength mean values (p ≤ 0.05).

CONCLUSION

The combined use of 5.25% NaOCl and 20% HEBP increased the push-out strength values of both NeoMTA 2 and White MTA, rendering them suitable to be used as an alternative chelating agent to EDTA.

Chitosan nanoparticles, Rose Bengal-chitosan activated photodynamic therapy as final irrigant on pushout bond strength, smear layer removal efficacy and antibacterial effectiveness against E.faecalis

AIM

Impact of final root canal disinfectants diode laser (DL), Rose Bengal photosensitizer (RBP), Chitosan Nanoparticles (CNPs), and CNPs modified RBP on Enterococcus faecalis (E.faecalis) survival rate, smear layer (SL) removal efficacy and push out bond strength (PBS) of resin sealer to the radicular dentin.

MATERIAL AND METHOD

Single rooted seventy-five human mandibular premolar teeth were sectioned at a level of cementoenamel (CEJ) and root canal treatment was performed using a ProTaper rotary instrument. To assess the antibacterial efficiency E.faecalis inoculation was performed using a pour plate method. The samples were arbitrarily allocated into five groups based on the final disinfectant received (n = 15) Group-1 (NaOCl+17 % EDTA), Group-2 (NaOCl+DL), Group-3 (NaOCl+CNPs), Group-4 (NaOCl+RBP activated by DL) and Group-5 (NaOCl+CNPs-RBP activated by DL). SEM analysis for SL removal was performed on five specimens from each group. Root canal obturation and sectioning were performed at cervical, middle, and apical levels. PBS and failure mode were analyzed using a universal testing machine (UTM) and stereomicroscope respectively. The data was subjected to analysis using one-way analysis of variance (ANOVA) and Tukey's post hoc test.

RESULT

Group 1 (NaOCl+17 % EDTA) (0.36 ± 0.01 CFU/mL) unveiled the maximum survival rate of tested bacteria. However, Group 5 (NaOCl+CNPs-RBP activated by DL) (0.11 ± 0.01 CFU/mL) displayed minimum survival of E.faecalis. The highest SL removal (1.44 ± 0.11) and bond integrity scores (12.23 ± 0.24 MPa) were recorded in the coronal section of Group 5 (NaOCl+ CNPs-RBP activated by DL) treated roots. However, the lowest removal of SL (3.15 ± 1.09) and PBS (7.24 ± 0.09 MPa) were recorded in Group 4 (NaOCl+RBP activated by DL) treated canals.

CONCLUSION

CNPs-RBP activated by DL as the final irrigant provided satisfactory antibacterial activity, SL removal, and bond strength outcomes compared to other tested groups.

PEEK and glass fiber post pushout bond strength and vickers hardness of canal disinfected with curcumin photosensitizer activated by microbubble emulsion and sodium-hypochlorite with EDTA

AIMS

Impact of different post-space disinfectants (Saline, Sodium hypochlorite (NaOCl) followed by ethylene-diamine-tetra-acetic acid (EDTA) and curcumin activated by microbubble emulsion (MBE) on the Vickers hardness (VH) of root canal dentin and extrusion bond strength (EBS) of Glass fiber post (GFP) and PEEK post.

METHODS

Ninety maxillary central incisors having fully formed roots were included. After the specimen's disinfection, root canal treatment was completed. Post space was prepared by removing gutta-percha using gates glidden drills. Teeth were then arbitrarily allocated into three groups based on the methods of disinfection regime used. Group 1: Saline, Group 2: NaOCl+ EDTA and Group 3: Curcumin activated by MBE (n = 30). Analysis of VH of radicular dentin was performed using a micro-Vickers tester on ten samples from each group. After post-space disinfection, twenty specimens from each group were further divided into two subgroups (n = 10) In group-1A 2A, and 3A, GFP was used. Whereas, prefabricated PEEK posts were used in 1B, 2B, and 3B subgroups. The PBS and failure modes were performed using a universal testing machine and stereomicroscope respectively. Data was analyzed using ANOVA and Tukey post hoc test to identify significant variations among groups concerning the MH and EBS of the different posts used (p = 0.05).

RESULTS

Group 2 (5.25 % NaOCl + 17 % EDTA) (0.15 ± 0.02 GPa) treated specimens presented lowest scores of VH. However, Group 1 (Saline) irrigated canals displayed the highest scores of surface hardness (0.25 ± 0.07 GPa). Additionally, a cervical third of 3A (CP activated by MBE + GFP) (11.22 ± 0.79 MPa) presented the highest scores of bond integrity. Whereas Group 1B (Saline + PEEK post) treated specimens presented the lowest scores of PBS (4.15 ± 0.15 MPa).

CONCLUSION

Curcumin activated by microbubble emulsion for disinfection of canal dentin demonstrated favorable VH. Similarly, glass fiber post-cemented in radicular walls disinfected with curcumin activated with MBE showed promising post-bond integrity to the canal dentin.

Analysis of the depth of penetration of an epoxy resin-based sealer following a final rinse of irrigants and use of activation systems: An in vitro study

Objective

The objective of the study was to compare and evaluate the depth of penetration of an epoxy resin-based sealer following a final rinse of 17% ethylenediaminetetraacetic acid (EDTA) and 18% 1-hydroxyethylidene 1, 1-diphosphonate (HEDP), with diode laser and passive ultrasonic activation (PUI): an in vitro confocal laser scanning microscopy study.

Materials and Methods

Fifty-two extracted human mandibular premolar teeth with single root and single canal were selected. They were disinfected in 0.1% thymol solution, cleaned of calculus and soft tissues, and stored in 0.1% thymol solution till use. All teeth were radiographed and selected as per the inclusion and exclusion criteria. The teeth were decoronated using a diamond disk under copious water spray to acquire a standardized root length of 14 mm. Working length was established by inserting a size 10-K file into each root canal until it is visible at the apical foramen and by subtracting 1 mm from the recorded length. Instrumentation of the root canal was done till master apical file size of F3 using ProTaper universal, rotary instruments. The canals were irrigated with 2 mL of 3% sodium hypochlorite between successive files. Teeth were randomly divided into four subgroups n = 12 according to the intervention. Passive ultrasonic irrigation and diode laser were used to activate the irrigants. Final irrigation was performed with distilled water. These specimens were examined using confocal laser scanning microscope (OLYMPUS FLUOVIEW FV 3000) for dentinal tubule penetration of the sealer. Two-way ANOVA test and Tukey's multiple post hoc test were used for statistical analysis.

Results

Highly significant difference was seen between the groups with EDTA and HEDP, with HEDP demonstrating the highest penetration. Among the activation techniques used in this study, PUI showed the highest penetration of the sealer. The least penetration was seen with diode laser activation and EDTA.

Conclusions

The irrigation activation techniques significantly influence the penetration of sealer into root dentinal tubules. When penetration of sealer with different irrigation techniques and irrigants was evaluated, significant greater level of sealer penetration was attained with PUI activation of HEDP.

Effect of Passion Fruit Juice in Removal of Smear Layer in Root Canal of Ex Vivo Human Teeth: A Scanning Electron Microscopic Study

CONTEXT

The smear layer produced during the instrumentation of the root canal contains both organic and inorganic components, and it is recommended to be removed as it has a mixture of bacteria and their byproducts. Irrigants like sodium hypochlorite (NaOCl), ethylenediaminetetraacetic acid (EDTA), endodontic irrigant, citric acid, etc., possess the ability to remove the smear layer. Considering the antimicrobial effect, antiinflammatory, cavity disinfectant, nontoxicity, better taste, and aroma of herbal products, a novel approach has been introduced in the field of endodontics.

AIMS

To assess the efficacy of passion fruit juice in removing the smear layer and its erosive potential in root canals after instrumentation by scanning electron microscopy.

MATERIALS AND METHODS

About 35 single-rooted premolars were divided into five groups-30% passion fruit extract (PFE), 17% EDTA, 17% EDTA + 5.25% NaOCl, 30% PFE + 17% EDTA, and saline. Following irrigation with the above irrigants, each tooth was split into two halves and examined and scored for smear layer removal (modified Torabinejad's criteria) using a scanning electron microscope.

STATISTICAL ANALYSIS

Overall comparison of the irrigant's action on removing the smear layer and their erosive potential was done using the Kruskal-Wallis test, and intergroup comparison of the irrigant action was done using the Mann-Whitney U test. All the statistical analyses were set with a significance level of p < 0.05.

RESULTS

A total of 30% PFE produced less erosion and statistically significant smear layer removal in the coronal and middle third of the root. When combined with 17% EDTA, it effectively removed the smear layer in all three-thirds of the root. Around 30% PFE + 17% EDTA is less erosive when compared to 17% EDTA + 5.25% NaOCl.

CONCLUSION

This study revealed that 30% PFE and 30% PFE + 17% EDTA are promising irrigants as root canal disinfectants in endodontics.

HOW TO CITE THIS ARTICLE

Venkatachalamoorthi V, Shivashankarappa PG, Adimoulame S, et al. Effect of Passion Fruit Juice in Removal of Smear Layer in Root Canal of Ex Vivo Human Teeth: A Scanning Electron Microscopic Study. Int J Clin Pediatr Dent 2023;16(S-2):S190-S194.

Quantitative assessment of transforming growth factor-β1 release from dentin matrix upon conditioning with ethylene diamine tetra-acetate, doxycycline hydrochloride, and propolis: An in vitro study

Background

Transforming growth factor-beta 1 (TGF-β1) is a key morphogen in regenerative endodontics that plays a central role in regulating cellular functions. Various chelating agents have been shown to release this growth factor upon conditioning. The objective of the study was to evaluate TGF-β1 release from the dentin matrix upon conditioning with ethylene diamine tetra-acetate (EDTA), doxycycline hydrochloride, and propolis.

Materials and Methods

Forty-two human 3rd molar teeth were collected and coronal portion of the teeth was sectioned to obtain dentin blocks with dimensions 2 mm × 2 mm × 2 mm. The blocks were then randomly divided into three groups depending on the conditioning agent used; Group 1: 17% EDTA, Group 2: doxycycline hydrochloride (100 mg/mL), and Group 3: propolis (250 μg/mL). Conditioned blocks were placed in 0.5 mL of phosphate buffered saline and incubated for 1 week for quantification.

Results

Highest TGF-β1 release was noted for propolis (0.21 ng/mL), followed by doxycycline hydrochloride (0.18 ng/mL) and 17% EDTA (0.14 ng/mL).

Conclusion

Doxycycline hydrochloride and propolis significantly enhanced the release of TGF-β1 from the dentin matrix compared to EDTA (P < 0.05). No significant difference was observed between doxycycline hydrochloride and propolis (P > 0.05). Doxycycline and propolis can be used as effective alternatives to EDTA during regenerative endodontic procedures.

Evaluation of Smear Layer Removal and Micro Hardness Alteration of Radicular Dentin after Using Various Chelating Agents - An Atomic Force Microscopic Study

Background and Aims

For endodontic therapy to be successful, the smear layer produced by the root canal instruments must be removed. The study's objective is to evaluate the effectiveness of radicular dentin microhardness modification and smear layer removal utilizing various chelating agents.

Materials and Methods

Extracted human mandibular single-rooted premolar teeth were selected for the study. The specimens were sectioned to obtain a standard root length and, working length determination was done. Cleaning and shaping were done in all the samples till the size F3 (Protaper universal). Based on the chelating agents using samples were randomly divided into four groups, Group-I: Saline (negative control), Group-II: 17% EDTA (DeSmear, Ahmedabad, Gujarat) (positive control), Group-III: 0.2% Chitosan (Everest-Biotech, Bengaluru), Group-IV: 20% N-Acetyl cysteine (NAC) (Sisco Research Laboratories, Mumbai), Group-V: 5% Pentetic acid (New Alliance Fine chem Pvt Ltd, Mumbai). All the samples were prepared for smear layer removal and surface roughness evaluation using an atomic force microscope.

Results

It was observed that significantly (P = 0.000) the mean roughness average was higher among group II EDTA (148 ± 8.5) followed by group III 0.2% Chitosan (92.5 ± 3.42), group IV 20% NAC (85.2 ± 2.17), and group V 5% Pentetic acid (73.3 ± 3.39) and least by group I Saline (59.3 ± 3.31). The highest smear layer removal was seen with group II (EDTA) followed by group III (0.2% Chitosan), group IV (20% NAC), and group V (Pentetic acid).

Conclusion

All the chelating agents removed smear layer in coronal third, middle third whereas none of them were able to entirely eliminate from the apical third. Chitosan with smear layer removal capacity equal to EDTA with limited roughness can be considered as a valid alternative as final irrigant.

Effectiveness of ultrasonic activation over glycolic acid on microhardness, cohesive strength, flexural strength, and fracture resistance of the root dentin

OBJECTIVES

The aim of this study was to evaluate the effectiveness of ultrasonic activation (US) over glycolic acid on microhardness, cohesive strength, flexural strength, and fracture resistance of root dentin, comparing with conventional final irrigation protocols.

METHODS

Samples were obtained from 140 extracted bovine teeth and distributed into four test groups: microhardness (50 teeth), cohesive strength (15 teeth), flexural strength (15 teeth), and fracture resistance (60 teeth). In all four tests, specimens were subdivided into five groups, according to final irrigation protocols: G1: distilled water (DW); G2: 17% ethylenediaminetetraacetic acid (EDTA); G3: 17% glycolic acid (GA); G4: 17% EDTA + US; and G5: 17% GA + US. The duration time of each protocol was set in 1 min. After irrigation protocols, the Vickers tester was used to evaluate microhardness and the universal testing machine was used to evaluate the cohesive strength, flexural strength, and fracture resistance of the root dentin. One-way ANOVA test and the Tukey HSD were used for multiple comparison tests in all evaluations (α = 5%).

RESULTS

In general, groups 2 (EDTA), 4 (EDTA + US), and 5 (GA + US) promoted the highest reduction of microhardness, being statistically different from other groups (p < 0.05). Cohesive strength, flexural strength, and fracture resistance data revealed that no differences between groups were observed (p > 0.05).

CONCLUSIONS

The association of GA and US results in microhardness reduction, with no influence on cohesive strength, flexural strength, and fracture resistance of the root dentin.

CLINICAL RELEVANCE

The use of US over GA has no influence on some mechanical properties of root dentin.

Push-Out Bond Strength of EndoSeal Mineral Trioxide Aggregate and AH Plus Sealers after Using Three Different Irrigation Protocols

OBJECTIVE

 The current study was designed to assess the bonding strength of EndoSeal MTA and AH Plus sealers after using three irrigation protocols as follows: (1) 17% Ethylenediamine tetraacetic acid, (2) 7% maleic acid, and (3) 37% phosphoric acid.

MATERIALS AND METHODS

 Push-out bond strength was evaluated for 60 middle root slices of 1-mm thickness each. They were horizontally cut from freshly extracted single-rooted human teeth. A hole in the root canal was made using a carbide round bur of 1.1 mm in diameter in a middle third root slice. Specimens were dipped in 2.5% NaOCl, and then they were grouped into three groups; G1: 17% EDTA, G2: 7% maleic acid, and G3: 37% phosphoric acid as a final irrigant for 3 minutes. Each group was subdivided into two subgroups, according to the type of sealer, either EndoSeal MTA or AH Plus.

STATISTICAL ANALYSIS

 After the full set of the sealer, the bond strength was evaluated with the push-out test by applying a force to each slice using a plunger with a 1-mm diameter. The one-way Tukey's post hoc test, analysis of variance (ANOVA) test, and Student's t-test were utilized to gather data and statistically evaluate it.

RESULTS

 The irrigation protocol used exhibited significant influence on the bond strength of EndoSeal MTA and AH Plus sealers. AH Plus sealer subgroups showed the highest bond strength with 7% maleic acid, followed by 37% phosphoric acid, and 17% EDTA. While in the EndoSeal MTA sealer subgroups, the highest bond strength was shown with the 17% EDTA followed by 7% maleic acid and 37% phosphoric acid, respectively.

CONCLUSION

 The present study revealed that the type of the final irrigant significantly impacts the bond strength of the sealer used. The AH Plus sealer bond strength was improved by using the 7% maleic acid as a final irrigant. In contrast, the EndoSeal MTA sealer showed the best results with the 17% EDTA as a final irrigant.

Etidronic acid and ethylenediaminetetraacetic acid associated with sodium hypochlorite have limited effect on the compressive fracture resistance of roots ex vivo

Aims:

To assess the effect of etidronic acid (EA) mixed with sodium hypochlorite (NaOCl) and two ethylenediaminetetraacetic acid-containing preparations (EDTA and SmearClear) alternated with NaOCl, as a final rinse, on root fracture resistance to a compressive force.

Materials and Methods:

Seventy-two premolar roots were randomly allocated to the following groups according to the irrigant solutions. For the EA group, 9% EA + 2.5% NaOCl were used throughout the assays (n = 21). The remaining groups received 2.5% NaOCl during and immediately after chemo-mechanical instrumentation. Intermediately, the roots received 17% EDTA (n = 19), or SmearClear (n = 16), or no irrigation (control) (n = 16) plus a final rinse with 2.5% NaOCl. The specimens were subjected to a vertical compressive force loaded at a crosshead speed of 0.02 mm/s parallel to the long axis of the root until fracture occurred. The results were compared statistically using the one-way analysis of variance for intergroup comparisons.

Results:

The negative control presented with the highest values, whereas the SmearClear presented with the lowest values, though no significant differences were found when comparing the different groups (P = 0.82).

Conclusions:

The use of EA + NaOCl or two EDTA formulations in association with NaOCl does not affect the fracture resistance of previously chemo-mechanically prepared roots.

Investigation of the effect of different chelation solutions on penetration of resin-based and bioceramic sealers with a novel method

This study aimed to investigate the effects of different chelation solutions on the penetration of resin-based and bioceramic root canal sealers into dentinal tubules using a device that assembles conventional microplate detection with automated digital microscopy. Eighty-four single-rooted teeth were prepared with 30.07 nickel-titanium instruments and divided into four groups of 21 according to the final irrigation solutions used: saline (control), ethylenediaminetetraacetic acid (EDTA), maleic acid (MA), and etidronic acid (HEBP). The samples were obturated with AH Plus, MTA Fillapex, or EndoSequence BC Sealer using the single-cone technique. The roots were then sectioned horizontally at 2, 6, and 10 mm and examined using a Cytation 5 reader and Gen5 software. Data were compared using two-way analysis of variance followed by univariate analyses and Tukey's multiple comparison test (p < .05). The mean penetration depth in the apical thirds was higher in the MA group than in the other groups (p = .013). The mean depth in the middle and coronal thirds was almost equal in the EDTA and HEBP groups. The mean depth was significantly higher in the coronal thirds of the root canals than in any other section in all final irrigation solution groups (p < .001). EndoSequence BC Sealer displayed higher penetration depth than AH Plus and MTA Fillapex, although the differences between the examined sealers were not statistically significant. The chelation solutions increased root canal sealer penetration into the dentinal tubule.

Scanning electron microscopy evaluation of chitosan and carboxymethyl chitosan as retrograde smear layer removing agents

Background:

The smear layer acts as a physical barrier against penetration of root canal medicaments and sealers, thus compromising the seal leading to microleakage.

Objectives:

This study was conducted to evaluate the efficacy of 17% ethylenediaminetetraacetic acid (EDTA), 0.2% chitosan solution, and 0.2% carboxymethyl chitosan (CMC) used as smear layer removing agents in retrograde root canal preparation using scanning electron microscopy (SEM).

Materials and Methodology:

Eighty single-rooted teeth extracted for periodontal reasons were collected for the study. Root canals were prepared and obturated with gutta-percha coated with AH plus resin sealer. Apical 3 mm of each root resected and Class I retrograde preparation carried out using ultrasonic handpiece and ultrasonic retro tips to a depth of 3 mm along the root long axis. In Group 1 (control), normal saline solution alone was used for smear layer removal. In Group II, 17% EDTA, Group III and IV were treated with 5 ml of 0.2% chitosan and 0.2% carboxyl methyl chitosan, respectively, for 3 min. Blinded evaluation of specimens using SEM was performed independently by two operators who registered the amount of the smear layer present on the surface of the canal walls based on the score described by Hülsmann et al.

Results:

Group I (saline) was least efficient in the removal of the smear layer. Group II (17% EDTA), Group III (0.2% Chitosan), and Group IV (0.2% CMC) efficiently removed the smear layer from the retrograde cavity with mean scores 1.35, 1.60, and 1.35, respectively. Statistically, no significant difference found in Group II (17% EDTA), Group III (0.2% Chitosan), and Group IV (0.2% CMC).

Conclusions:

About 0.2% CMC and 0.2% chitosan can be better alternatives to 17% EDTA for smear layer removal due to their biological advantages.

A comparative evaluation of smear layer removal by using ethylenediamine tetraacetic acid, citric acid, and maleic acid as root canal irrigants: An in vitro scanning electron microscopic study

Introduction:

Irrigants remove or dissolve smear layer formed during instrumentation. Thus it is important to study the effect of different irrigant solutions on smear layer removal.

Objectives:

The aim of this study is to determine which irrigant effectively removes the smear layer from the coronal, middle, and apical third of the root canal.

Materials and Methodology:

One hundred and twenty single-rooted mandibular premolars were decoronated and biomechanical preparation was done through hand instrumentation up to size 40 k file with 2.5% NaOCl irrigation between each successive filing, followed by irrigation with 5 ml of saline. The teeth were divided into Groups I, II, III, and IV containing 30 samples each and irrigated with 5 ml of 17% ethylenediamine tetraacetic acid (EDTA), 10% Citric acid, 7% Maleic acid and normal saline respectively for 1 min and final irrigation was done with 5 ml of distilled water of each sample. The canals were dried with 2% absorbent paper points. The roots were then split with a chisel and mallet. One-half of each tooth was selected and then was analyzed using a scanning electron microscope. The dentinal surfaces were observed at the cervical, middle, and apical third with ×2000 for the smear layer. The scores were attributed, according to Torabinejad et al. rating system.

Results:

7% maleic acid and 10% citric acid both are equally effective in smear layer removal from coronal and middle third, but in apical third 7% maleic acid is more effective than 10% citric acid. Between citric acid and EDTA, both are equally effective in smear layer removal from coronal and middle third, but in apical third, 10% citric acid is more efficacious than 17% EDTA.

Conclusion:

Within the limitations of the study, it can be concluded that all three tested irrigants removed the smear layer from coronal, middle, and apical third. However, in apical third 7% maleic acid is the most efficacious irrigant in smear layer removal.

Comparative apical sealing evaluation of two bioceramic endodontic sealers

AIM

The current study aims to evaluate, using scanning electronic microscopy, the sealing ability of two bioceramic endodontic sealers, one consecrated and one experimental.

METHODS

Twenty monoradicular teeth were included in the study. The teeth were endodontically prepared at the working length. The shaping and cleaning involved the use of chelating gel MM EDTA 19% and continuous irrigation with sodium hypochlorite 2.5%. The radicular filling was performed using gutta-percha in association with a sealer. Ten teeth were filled with consecrated endodontic filling material and the others ten with the experimental bioceramic based sealer.

RESULTS

The evaluation of the sealers using SEM analysis allowed the identification and the measurement of gaps on the radicular dentin/sealer interface and the degree of apical sealing ability. No significant statistical difference was observed between the gap dimensions in the three areas for the tested bioceramic materials (p<0.005). In the apical region a homogenous layer with extensions intersecting the hybrid layer was observed when the experimental bioceramic sealer was used. In case of teeth filled with commercial sealer, peripheral hybrid extended areas were identified.

CONCLUSIONS

The two bioceramic sealers presented similar apical sealing. Gaps were identified in both sealers but also the presence of hybrid layer was identified.

Time-Dependent Effect of Various Irrigants for Root Canal on Smear Layer Removal

Background:

Existence of smear layer in root canals caused by instrumentation is believed to prevent penetration of irrigating agents, thereby resulting in endodontic treatment.

Aims and Objectives:

To compare and evaluate the effectiveness of two irrigants: 17% ethylenediaminetetraacetic acid (EDTA) and mixture of tetracycline isomer, an acid, and a detergent (MTAD) as final agents for eliminating the smear layer.

Materials and Methods:

We included 50 human lower premolar teeth whose crowns were sectioned at cementoenamel junction. The sample was randomly grouped into five groups, each with 10 teeth. Group 1: 1 mL of 17% EDTA as final rinse for 1 min, Group 2: 1 mL of 17% EDTA for 30 s, Group 3: 5 mL of MTAD for 2.5 min, Group 4: 5 mL of MTAD for 5 min, and Group 5: saline. The specimens were sectioned vertically all along the long axis and fixed on an aluminum stub for gold ion sputtering. Scanning electron microscope was used to observe the specimens, and photomicrographs were taken at coronal, middle, and apical thirds of canal, and assessed by Torabinejad scoring system by two examiners, and the observations were analyzed statistically.

Results:

When Group 1 and Group 2 and Groups 3 and 4 were compared, we found a significant variation in removal of smear layer at cervical and middle thirds, and insignificant difference at apical third. In comparison with EDTA and saline, MTAD was more efficient significantly in middle and cervical thirds and insignificant at apical third.

Conclusion:

MTAD is an efficient irrigant for removing smear layer than EDTA and saline.

Evaluation of SmearOFF, maleic acid and two EDTA preparations in smear layer removal from root canal dentin

Objectives: To evaluate SmearOFF, 7% maleic acid (MA) and two different preparations of ethylenediaminetetraacetic acid (EDTA) in smear layer removal.Materials and methods: Fifty single-rooted teeth were separated into five groups, instrumented and irrigated as follows: (1) SmearOFF, (2) 7% MA, (3) 18% EDTA (pH 11.4), (4) 17% EDTA (pH 8.5) and (5) 0.9% saline. Teeth samples were blinded and examined by scanning electron microscopy with Image J software.Results: Eighteen percent EDTA was less efficient when compared to SmearOFF and MA at all thirds of the root canal system. There was no difference between SmearOFF and MA in the coronal and middle thirds. In the apical third, MA removed more smear layer. Seventeen percent EDTA was as efficient as SmearOFF and MA in coronal and middle third but not in the apical third. Eighteen percent EDTA removed smear layer less efficiently in the coronal and middle thirds than 17% EDTA; in the apical third, there was no difference observed. In the saline group, all specimens were heavily smeared. There was no significant difference between 18% EDTA and saline at all canal thirds.Conclusions: SmearOFF and 17% EDTA (pH 8.5) had better smear layer removal capability in the coronal and middle thirds of the root canal system. In the apical third, 7% MA was superior. 18% EDTA (pH 11.4) and saline had poor smear layer removal ability.

Effect of ultrasonic activation on calcium ion quantification, smear layer removal, and canal cleaning efficacy of demineralizing irrigants

Background

Effective removal of smear layer ensures better penetration of irrigants ensuring root canal disinfection and has the potential of sealing dentinal tubules during obturation.

Aim

The aim of this study is to evaluate the canal cleaning efficacy and calcium ion liberation with the use of demineralizing irrigants, namely, 17% ethylenediaminetetraacetic acid (EDTA), 7% maleic acid, and 10% citric acid with or without ultrasonic (US) activation.

Materials and Methods

Crowns of 62 extracted maxillary central incisors were decoronated and root canals prepared. Based on the final irrigant teeth were divided into following groups (n = 10), namely, 10% citric acid, 7% maleic acid, 17% EDTA, and 10% citric acid with US activation, 7% maleic acid with US activation, and 17% EDTA with US activation. Irrigants were subjected to inductively coupled plasma-atomic emission spectroscopy followed by debris scoring and scanning electron microscope analysis.

Statistical Analysis

One-way analysis of variance with the Bonferroni's correction for multiple testing was employed.

Results

About 10% citric acid with US activation liberated the highest calcium ions and removed the maximum smear layer.

Conclusions

Citric acid with US activation is a potentially effective irrigation regimen with sodium hypochlorite.

Unusual Root Canal Irrigation Solutions

Microorganisms and their by-products play a critical role in pulp and periradicular pathosis. Therefore, one of the main purposes of root canal treatment is disinfection of the entire system of the canal. This aim may be obtained using mechanical preparation, chemical irrigation, and temporary medication of the canal. For this purpose, various irrigation solutions have been advocated. Common root canal irrigants, such as sodium hypochlorite, chlorhexidine, and a mixture of tetracycline, acid, and detergent have been extensively reviewed. The aim of this review was to address the less common newer root canal irrigation solutions, such as citric acid, maleic acid, electrochemically activated water, green tea, ozonated water, and SmearClear.

Scanning Electron Microscopic Evaluation of Smear Layer Removal Using Isolated or Interweaving EDTA with Sodium Hypochlorite

Introduction:

The aim of this study was to verify the effect of alternating 2.5% sodium hypochlorite (NaOCl) and 17% ethylenediaminetetraacetic acid (EDTA) on the smear layer removal from root canal surfaces.

Methods and Materials:

A total of 15 single-rooted human teeth, instrumented with ProTaper files, were randomly distributed in 3 groups. In group 1 (n=7) the canals were irrigated with 1 mL of 2.5% NaOCl between files and final irrigation was done with 1 mL of 2,5% NaOCl, followe by 1 mL of 17% EDTA, for a perio of 15 sec with new irrigtion of 1 mL of 2,5% NaOCl at each change of files. In group 3 (control group) (n=1), saline solution was used. All samples were cleaved into two sections, metalized and analyzed under scanning electron microscopy (SEM). The presence or absence of smear layer in the cervical, middle and apical thirds, with scores varying from 1 to 3, respectively were evaluated. The data were submitted to nonparametric Mann-Whitney U test. The level of significance was set at 0.05.

Results:

It was observed that there was a greater discrepancy between groups with respect to the apical third. In the other areas there was a greater similarity between the scores attributed to the groups. There was a statistically significant difference between the groups only in the apical third, when group 1 presented the higher median (P<0.05).

Conclusion:

The alternating use of EDTA during instrumentation with NaOCl was the most effective irrigation method to remove the apical smear layer. Both forms of irrigation were effective on removal of the smear layer in the coronal and middle thirds of the canals.

Effect of Different Irrigating Solutions on Depth of Penetration of Sealer into Dentinal Tubules: A Confocal Microscopic Study

Aim:

The aim of the study was to evaluate the effect of different irrigating solutions used in final irrigation on depth of sealer penetration into dentinal tubules.

Materials and Methods:

Thirty recently extracted, human mandibular premolar teeth with single canals were randomly divided into two groups, and one of the two irrigants was used in each group - Group A (Chitosan) and Group B (Ethylenediaminetetraacetic acid). All the teeth were obturated with gutta-percha and AH 26^® sealer labeled with fluorescent dye. The teeth were sectioned at distances 2, 5, and 8 mm from the root apex. Maximum depth of sealer penetration was measured using confocal laser scanning microscopy.

Statistical Analysis:

Statistical analysis used One-way analysis of variance and t-test.

Results:

At coronal third depth, the sealer penetration was greater in ethylenediaminetetraacetic acid (EDTA) group; however, depth of sealer penetration was greater at apical third in chitosan group.

Conclusion:

Final irrigation with EDTA and chitosan after the use of sodium hypochlorite affected sealer penetration.

Comparative evaluation of canal cleaning ability of various rotary endodontic filesin apical third: A scanning electron microscopic study

BACKGROUND

The purpose of this study was to evaluate the canal cleaning ability of three novel endodontic rotary instruments and compare with ProTaper files as a control in apical third of root canals under scanning electron microscopy (SEM).

MATERIALS AND METHODS

Eighty freshly extracted mandibular premolars were selected according to inclusion criteria. Buccal cusp tips were ground to ensure having a flat coronal reference point with a total tooth length of 16 mm for all samples. Teeth were divided equally into four groups: Group I (ProTaper group), Group II (ProTaper next group), Group III (variable taper group), and Group IV (self-adjusting file [SAF] group). Using SEM, the dentinal surfaces were observed and rated at apical thirds with a magnification of ×1000 for the presence/absence of smear layer and debris. Descriptive analysis was performed, and analysis of variance with Bonferroni post hoc test was carried out for comparison between the groups, at a significance level of 0.05.

RESULTS

There was statistically significant difference between Group II and Group IV for debris (P = 0.047) and smear layer (P = 0.037).

CONCLUSION

In apical third of root canal, SAF showed statistically significant canal cleaning ability due to combined effect of continuous streaming irrigation with effectively replacing the irrigant from the apical portion of the root canal, irrigants activation through the creation of turbulence, and its self-adapting design to root canal anatomy with a scrubbing motion on the canal walls.

Comparative analysis of endodontic smear layer removal efficacy of 17% ethylenediaminetetraacetic acid, 7% maleic acid, and 2% chlorhexidine using scanning electron microscope: An in vitro study

Aim:

The aim of the present study was to evaluate the efficiency of different endodontic irrigants in the removal of smear layer through scanning electron microscopic image analysis.

Materials and Methods:

The present in vitro study was carried out on 45 single-rooted extracted human mandibular premolar teeth with single canal and complete root formation. Teeth were randomly assigned to three groups with 15 teeth in each group. Group I samples were irrigated with 17% ethylenediaminetetraacetic (EDTA) irrigation, Group II with 7% maleic acid irrigation, and Group III with 2% chlorhexidine irrigation. Scanning electron microscope evaluation was done for the assessment of smear layer removal in the coronal, middle, and apical thirds. Comparison of the smear layer removal between the three different groups was done by Kruskal–Wallis test, followed by Mann–Whitney U test for comparing individual groups. A P value less than 0.05 was considered to be statistically significant.

Results:

Statistically significant difference was seen between the two test groups (17% EDTA vs. 7% maleic acid and 17% EDTA vs. 2% chlorhexidine) in smear layer removal at coronal, middle, and apical thirds of the root canal. The most efficient smear layer removal was seen in Group I with 17% EDTA irrigation compared with other groups (P < 0.05) and the least by 2% chlorhexidine.

Conclusion:

The present study shows that 17% EDTA efficiently removes the smear layer from root canal walls.

To Evaluate the Efficacy of an Innovative Irrigant on Smear Layer Removal - SEM Analysis

INTRODUCTION

The goal of endodontic therapy is to completely eliminate the microorganisms and the smear layer from the root canal in order to provide a good seal of the root filling materials.

AIM

The aim of this study was to find a viable alternative irrigant, which is easily available with less erosion and clinically acceptable smear layer removal by comparing the efficacy of EDTA and commercially available super-oxidized water, named Oxum, as a final rinse on smear layer removal and erosion in relation to coronal, middle and apical thirds of radicular dentin using Scanning Electron Microscope (SEM) analysis.

MATERIALS AND METHODS

Freshly extracted 30 human lower second premolar teeth with straight roots and type I canal anatomy were selected. The root canals were cleaned and shaped using Universal Protaper Rotary System. Irrigation was performed with 1 ml of 2.5% of NaOCl solution after each instrument change. The final irrigation (5 ml) sequence was as follows: Group I- 17% EDTA, Group II - OXUM, and Group III - 0.9% saline (control) for one minute. Then, the root canals were finally irrigated with 5ml of distilled water to remove any precipitate. The roots were then gently split into two halves using a chisel and subjected to SEM analysis.

RESULTS

The SEM photomicrographs were evaluated by two independent examiners and Mann Whitney results showed that there was no statistically significant difference between the two examiners. Non-parametric statistical analysis of all experimental groups showed significant difference between coronal, middle and apical third for smear layer removal with p-value<0.05. For erosion, in group II (oxum) showed statistically significant difference between coronal, middle and apical third and it showed significantly less dentine erosion when compared to EDTA.

CONCLUSION

Within the limitations of the present study, Oxum the commercially available super-oxidized water proved to be equally effective in smear layer removal with less erosion when compared to EDTA.

Scanning electron microscopy (SEM) evaluation of sealing ability of MTA and EndoSequence as root-end filling materials with chitosan and carboxymethyl chitosan (CMC) as retrograde smear layer removing agents

AIM

The purpose of this study was to evaluate the sealing ability of mineral trioxide aggregate (MTA) and EndoSequence with chitosan and carboxymethyl chitosan (CMC) as retrograde smear layer removing agents using scanning electron microscopy (SEM).

MATERIALS AND METHODS

Forty human single rooted teeth were taken. Crowns were decoronated and canals were obturated. Apically roots were resected and retrograde cavities were done. Based on the type of retrograde material placed and the type of smear layer removal agent used for retrograde cavities, they were divided into four groups (N = 10): Group I chitosan with EndoSequence, group II chitosan with MTA, group III CMC with EndoSequence, and Group IV CMC with MTA. All the samples were longitudinally sectioned, and the SEM analysis was done for marginal adaptation.

STATISTICAL ANALYSIS

Kruskal-Wallis and Mann-Witney analysis tests.

RESULTS

SEM images showed the presence of less gaps in group III, i.e., CMC with EndoSequence when compared to other groups with statistically significant difference.

CONCLUSION

Within the limited scope of this study, it was concluded that EndoSequence as retrograde material showed better marginal sealing ability.

Smear layer removal efficacy of combination of herbal extracts in two different ratios either alone or supplemented with sonic agitation: An in vitro scanning electron microscope study

Objectives:

The study aimed to evaluate the effectiveness of the combination of two natural extracts in varying ratios for removal of smear layer either alone or supplemented with sonic agitation.

Materials and Methods:

Fifty extracted single-rooted teeth were collected, disinfected and decoronated below the cementoenamel junction to obtain standardized root length of 10 mm. Root canals were instrumented using rotary files at working length 1 mm short of the apex. Specimens were divided into six groups according to the irrigation protocol as follows: Group A – Distilled water, Group B – 17% ethylenediaminetetraacetic acid, Group C – Herbal extracts in 1:1 ratio, Group D – Herbal extracts in 1:1 ratio supplemented with sonic agitation, Group E – Herbal extracts in 2:1 ratio, Group F – Herbal extracts in 2:1 ratio supplemented with sonic agitation. Specimens were longitudinally sectioned and evaluated under scanning electron microscope for smear layer removal efficacy. Obtained scores were statistically analyzed using one-way analysis of variance and post-hoc test.

Results:

Among all, Group B showed the best results followed by Group F. Remaining other groups showed inferior outcome (P < 0.05).

Conclusion:

The combination of two extracts in 2:1 ratio was slightly better than 1:1 ratio and the smear layer removal efficacy was further improved when accompanied with sonic agitation.