Smear Layer Removal and Canal Cleanliness Using Different Irrigation Systems (EndoActivator, EndoVac, and Passive Ultrasonic Irrigation): Field Emission Scanning Electron Microscopic Evaluation in an In Vitro Study

Evaluation of canal patency and cleanliness following retreatment of bioceramic sealer-obturated root canals using three different irrigant activation protocols

This study evaluated the effectiveness of three different irrigant activation techniques in cleaning and establishing patency during retreatment of root canals obturated with gutta-percha and bioceramic sealer. 60 extracted premolars with oval-shaped canals were instrumented and obturated with gutta-percha and EndosequenceBC sealer using the 'warm hydraulic condensation' technique. The teeth were retreated using Protaper Universal Retreatment and XP-Endo Shaper system and divided into four groups according to the irrigant activation protocol used: control, passive ultrasonic irrigation (PUI), Endovac irrigation (EVI) and XP-Endo Finisher R (XPFR). Apical patency was achieved in all the samples of the XPFR group (100%), which showed a significantly higher success rate compared with the control (73.3%) and EVI groups (73.3%) (p < 0.05). The scanning electron microscopic evaluation revealed significantly cleaner middle and apical third root canals in the PUI and XPFR groups compared with the control group (p < 0.05). These findings suggest that XPFR effectively cleans and establishes patency in root canals filled with bioceramic sealers.

Debris and Smear Layer Removal in Curved Root Canals: A Comparative Study of Ultrasonic and Sonic Irrigant Activation Techniques

The aim of this study was to compare the cleaning efficacy of three irrigant activation devices with a control of non-activated syringe and needle irrigation in curved root canals. Sixty human curved roots were endodontically prepared and divided into four groups (n = 15) with similar root curvature distributions. Final irrigation using 4% NaOCl was performed with a syringe and needle (30-G) alone, or with Eddy sonic powered irrigation system (polymeric tip #0.25/0.06), Endosonic ultrasonic activation (polymeric tip #0.25/0.03), or Irrisafe ultrasonic activation (stainless-steel tip, #0.25/0.00). SEM was used to evaluate cleaning efficacy, employing five-score systems for debris and smear layer. While no significant difference in debris removal was observed between Endosonic or Irrisafe activation and non-activated irrigation, Eddy sonic powered irrigation system significantly improved debris removal in the apical third of curved root canals. Smear layer removal was effective in coronal and mid-root sections for all groups but less so in the apical third. Thus, Eddy sonic powered irrigation system demonstrated higher efficacy in removing debris from the apical third of curved root canals compared with non-activated syringe and needle irrigation. However, all three irrigant activation systems exhibited no difference from the non-activated control in smear layer removal.

Comparative evaluation of the effect of ultrasonic and rotary agitation of herbal irrigating solutions on smear layer: A SEM study

Context

Instrumentation and irrigation balance helps in effective removal of endodontic microbes housing inside the smear layer.

Aim

This study aimed to (1) evaluate whether activation of the irrigating solutions with two different systems during the final irrigation step can lead to smear layer formation in the middle and apical third of the root canal and (2) evaluate and compare the smear layer removal ability of the aqueous extracts of Emblica officinalis and Morinda citrifolia.

Materials and Methods

A total of 72 single-rooted teeth were prepared up to F4 ProTaper. The specimens were assigned into eight groups of nine teeth each, according to the final irrigant and activation techniques. Further, the teeth were evaluated under SEM for endodontic smear layer at the middle and apical third.

Statistical Analysis

Inferential statistics included Pearson's Chi-square. Level of significance was set at 0.05 at 95% confidence level.

Results

Ultrasonic activation system showed significant (P = 0.000) amount of smear layer compared to XP-Endo Finisher file. A significant difference (P = 0.00) in the smear layer removal was observed when 6% M. citrifolia was activated with XP-Endo Finisher file both in the middle and apical third.

Conclusion

Within the limitations of this in vitro study, it can be concluded that smear layer formation was noted with ultrasonic and XP-Endo Finisher file when saline was used as an irrigant. 6% M. citrifolia when activated with XP-Endo Finisher file showed best results among all other experimental groups.

Effectiveness of a new endodontic irrigation system for removing smear layer and dissolving simulated organic matter

OBJECTIVES

The study aimed to evaluate the potential for the dissolution of organic tissue in areas of simulated complexity and cleaning of root canal walls of the new iVac® endodontic irrigation system.

MATERIAL AND METHODS

Thirty mandibular premolars were evaluated by scanning electron microscopy before and after biomechanical preparation. Then, they were distributed according to the final irrigation protocol into groups with conventional irrigation, ultrasonic agitation with metallic insert (UA), and iVac® system, and new photomicrographs were obtained. For tissue dissolution analysis, glass capillaries filled with catgut were attached to the cervical and apical thirds of twenty-one prototyped upper incisors. They were weighed before and after the previously mentioned irrigation protocols. The data were statistically compared with a significance level of 5%.

RESULTS

The final irrigation provided greater cleaning of the root canal walls in the cervical, middle, and apical thirds of the root canals (P < 0.05), with no statistically significant difference between UA and iVac®, regardless of the analyzed thirds. Both ultrasonic irrigation protocols dissolved a significantly greater volume than the conventional irrigation protocol (P < 0.05), with no difference between the two protocols (P < 0.05).

CONCLUSIONS

The iVac® system showed root canal wall cleaning and tissue dissolution similar to UA with a metallic insert, and both were superior to conventional irrigation.

CLINICAL RELEVANCE

The new irrigation system iVac is more effective than conventional irrigation and has similar root canal wall cleaning and tissue dissolution to UA.

A Comparative Evaluation of the Cleaning Efficacy of Five Different Root Canal Irrigation Devices: A Histological Study

OBJECTIVES

 This study is aimed to evaluate the cleaning efficacy of five different irrigation systems as SonicMax, RinsEndo, EndoVac, passive ultrasonic irrigation (PUI), and manual needle irrigation (MNI) to histologically evaluate the presence of organic structures and the penetration of irrigation solution.

MATERIALS AND METHODS

 Forty-two single-rooted, extracted human mandibular premolars were used in the study. Each tooth was decoronated at the cementoenamel junction and the root canals were instrumented using ProTaper rotary instruments in a crown-down manner. The specimens were randomly divided into five experimental groups (n = 7) Group (1) SonicMax, group (2) RinsEndo,group (3) EndoVac, group (4) PUI, group (5) MNI, and the control groups (n = 7). Each system used 2.5% sodium hypochlorite (NaOCl), 17% ethylenediamine tetraacetic acid (EDTA), and 2.5% NaOCl, respectively, in the experimental groups. The control group did not receive any final irrigation.The measurements were analyzed by employing two-way analysis of variance multivariate results to show significant differences between the length of the dentin tubules in the apical, middle, and coronal of the six groups. The post-hoc test was used when groups were compared by pairs.

RESULTS

 The results of this study indicate that among the five groups, the RinsEndo and EndoVac were found to be most effective in the cleaning of root canals. The RinsEndo shows highly significant results in the cleaning efficiency of the coronal and middle parts compared with the other groups. The cleaning efficiency in the apical area was the same for RinsEndo and EndoVac.

CONCLUSION

 The result of our study indicates that RinsEndo and EndoVac may be more effective in clinical practice.

Impact of the final agitation system in the irrigant diffusion inside the root canal: A micro-CT analysis

This study evaluated, through micro-computed tomography (micro-CT), the volume of irrigant diffusion by different techniques of final agitation. Sixty mesiobuccal canals were scanned in a micro-CT and standardised according to the volume. They were instrumented with the MTwo 40/04 system and using the Terebrix 35 contrast solution as irrigant, were divided into six groups (n = 10): Conventional irrigation with syringe and needle (CI), EndoActivator (EA), EasyClean (EC), RinsEndo (RE), Utrasonic agitation (UI) and XP-Clean (XP). A second micro-CT scan was performed and the total irrigant volume and in the final 3 mm apical were determined. The data were analysed using the Anova, Kruskal-Wallis and Dunn tests (p < 0.05). UI and XP showed a higher percentage of total diffusion than CI, EA and RS groups (p < 0.05). In apical diffusion, there was no significant difference between groups (p > 0.05). The final agitation system increases the diffusion of irrigating agents inside the root canal.

Comparative Evaluation of Different Irrigant Agitating Devices for Debris Removal from the Mesial Roots of Mandibular Molars: An In Vitro Study

AIM

To evaluate the efficiency of debris removal from the mesial root canals and isthmus of mesial roots of mandibular molars after final irrigant agitation with XP-endo Shaper, EndoVac (EV), plastic finishing file, and conventional needle irrigation.

METHODS AND MATERIALS

Forty extracted human mandibular first molar teeth with the isthmus between the mesial roots were selected, access cavities were prepared and distal roots were decoronated. All the mesial root specimens were mounted in acrylic, sectioned at the coronal, middle, and apical thirds, along with the resin block, and examined for debris in the canals and isthmus before the start of the procedure using a stereomicroscope and were mounted back in a custom-made jig. After determination of the working length, they were allocated to the following four different irrigant activation groups (n = 10): Group I-XP-endo Finisher; group II-EndoVac; group III-plastic finishing file; and group IV-standard needle irrigation. After biomechanical preparation (BMP) till F3, final agitation was done for debris removal with the respective agitating devices, and all the samples were examined under a stereomicroscope for the amount of debris in the canal after final agitation.

RESULTS

Of all the irrigation devices used, the XP-endo Finisher and EV showed more debris removal when compared to other groups (p < 0.05). The plastic finishing file in continuous rotation was more efficient in cleaning debris compared with conventional needle irrigation (p < 0.05).

CONCLUSION

The XP-endo Finisher and EV showed a significant difference in cleaning efficacy than the plastic finishing files. So, these can be used as adjunctive for agitating the final irrigant.

CLINICAL SIGNIFICANCE

The irrigant agitation devices promote the penetration of irrigants into the intricate root canal anatomy and increase their antibacterial and tissue-dissolving effectiveness thereby improving the success rate and treatment outcome.

Efficacy of Three Irrigation Methods in Removing Calcium Hydroxide from Curved Root Canals: An In Vitro Micro-CT Study

Aims and Objectives

This in vitro study aimed to compare the efficacy of three different irrigation methods in removing calcium hydroxide from curved root canals and to estimate the amount of residual medicament using microcomputed tomography.

Materials and Methods

Thirty extracted molars with curved mesial root canals, ranging from 25° to 30°, were prepared with ProTaper Next using X2 to full working length and were filled with calcium hydroxide. Teeth also were randomly divided into four groups: group 1 (n = 8)- Erbium: Yttrium-Aluminum-Garnet (Er:YAG) laser; group 2 (n = 8)-EndoActivator; group 3 (n = 8)-EndoVac; and a control group (n = 6)-negative control with no calcium hydroxide. Microcomputed tomography was used to evaluate the residual amount of filling material. Statistical analysis was performed using IBM SPSS Statistics 26, with a significance level of 0.05. Descriptive statistics, student t test, and Chi-square test were applied for data analysis.

Results

The greatest amount of residual calcium hydroxide was observed in the samples with EndoVac irrigation (0.515 mm3), followed by EndoActivator (0.381 mm3) and Er:YAG laser (0.121 mm3). However, no statistically significant difference was observed between the groups. The greatest residual amount was observed in the apical third (0.419 mm3), followed by the middle (0.050 mm3) and the coronal (0.015 mm3).

Conclusions

No statistically significant differences were observed in the efficacy of the tested techniques for removing calcium hydroxide from curved root canals, whereas a significant difference was observed in the distribution of residual material depending on the technique used. The removal of the calcium hydroxide was more effective in the coronal and middle third of the canal. The greatest residual material was found in the apical portion of the root canal.

A Novel Endodontic Approach in Removing Smear Layer Using Nano and Submicron Diamonds with Intracanal Oscillation Irrigation

Sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) are commonly recommended for effectively removing organic and inorganic components in the smear layer. This layer is found on root canal walls after root canal instrumentation. However, high-concentration EDTA reduces the strength of dentin and the dissolution efficacy of organic substances in NaOCl solution. The objective of this study was to investigate the efficacy of applying nano and submicron diamonds in irrigation solutions with sonic and ultrasonic oscillation for removing the smear layer during endodontic treatment. Extracted single-rooted human teeth were instrumented with ProTaper^® Gold (Dentsply Sirona) nickel-titanium rotary instruments. Subsequently, each canal was irrigated with 3% NaOCl, 17% EDTA, distilled water, and 10-1000 nm-sized nano and submicron diamond irrigation solutions, respectively. Sonic and ultrasonic instruments were compared for oscillating the irrigation solutions. The teeth were processed for scanning electron microscopy to observe the efficiency of smear layer removal on the canal walls. Our results indicated that diamond sizes of 50 nm and above irrigation solutions showed significant effectiveness in removing the smear layer following the oscillation of sonic instruments for 10 s. Ultrasonic assisted 500 nm and 1000 nm diamond solutions significantly differed from the other diamond-sized solution in their ability to remove the smear layer. These results suggest that sonic and ultrasonic oscillation with specific sizes of nano and submicron diamond irrigation solution can be used as an alternative approach to removing the smear layer during endodontic treatment. The potential clinical application of root canal treatments can be expected.

To evaluate and compare the effect of 17% EDTA, 10% citric acid, 7% maleic acid on the dentinal tubule penetration depth of bio ceramic root canal sealer using confocal laser scanning microscopy: an in vitro study

Background: The main factors that affect the success of an endodontic infection are effective cleaning and shaping of the root canal system including complete disinfection by using chemical irrigating solutions and obturation with an endodontic sealer to provide a fluid-tight seal. Using rotary and hand instruments for shaping and cleaning the root canal along with irrigants produces a smear layer on the surface of the root dentin affecting the penetration of the endodontic sealer into the dentinal tubules. This smear is difficult to remove with the use of only endodontic irrigants, hence, chelating agents were introduced in adjunct with irrigating solutions for irrigation protocol for effective removal of smear layer which affect the penetration of endodontic sealers into the dentinal tubules. Methods: 32 mandibular premolar teeth were used. The biomechanical preparation was done till Protaper F3 size. Irrigation was done with 2.5 mL sodium hypochlorite (NaOCl) solution after each instrumentation change for 1 min. Samples were then divided into 4 groups according to the irrigating solution used as the final rinse used with passive ultrasonic agitation. The groups were: Group I: 5 ml of saline, Group II: 5ml of 17% ethylenediaminetetraacetic acid, Group III: 5 ml of 10% citric acid, Group IV: 5 ml of 7% maleic acid each for one minute. All the canals were obturated with BioRoot tmRCS with gutta-percha using the ultrasonic condensation technique. For staining the samples for Confocal LASER microscopy, BioRoot tmRCS was mixed with Rhodamine B dye. Results: The maximum penetration of bio-ceramic sealer was observed in the coronal region. At the apical third, the maximum sealer penetration was seen with 7% maleic acid. Conclusions: Maximum sealer penetration was seen in the coronal section followed by the middle and apical section. Maximum sealer penetration was seen with 7 % maleic acid at the apical third.

To evaluate and compare the effect of 17% EDTA, 10% citric acid, 7% maleic acid on the dentinal tubule penetration depth of bio ceramic root canal sealer using confocal laser scanning microscopy: an in vitro study

Background: The main factors that affect the success of an endodontic infection are effective cleaning and shaping of the root canal system including complete disinfection by using chemical irrigating solutions and obturation with an endodontic sealer to provide a fluid-tight seal. Using rotary and hand instruments for shaping and cleaning the root canal along with irrigants produces a smear layer on the surface of root dentin affecting the penetration of the endodontic sealer into the dentinal tubules. This smear is difficult to remove with the use of only endodontic irrigants, hence, chelating agents were introduced in adjunct with irrigating solutions for irrigation protocol for effective removal of smear layer which effect the penetration of endodontic sealers into the dentinal tubules. Methods: 32 mandibular premolar teeth were used. The biomechanical preparation was done till Protaper F3 size. Irrigation was done with 2.5 mL sodium hypochlorite (NaOCl) solution after each instrumentation change for 1 min. Samples were then divided into 4 groups according to the irrigating solution used as the final rinse used with passive ultrasonic agitation. The groups were: Group I: 5 ml of saline, Group II: 5ml of 17% ethylenediaminetetraacetic acid, Group III: 5 ml of 10% citric acid, Group IV: 5 ml of 7% maleic acid each for one minute. All the canals were obturated with BioRoot tmRCS with gutta-percha using the ultrasonic condensation technique. For staining the samples for Confocal LASER microscopy, BioRoot tmRCS was mixed with Rhodamine B dye. Results: The maximum penetration of bio-ceramic sealer was observed in the coronal region. At the apical third, the maximum sealer penetration was seen with 7% maleic acid. Conclusions: Maximum sealer penetration was seen in the coronal section followed by the middle and apical section. Maximum sealer penetration was seen with 7 % maleic acid at the apical third.

Current Trends in Irrigation Solution and Adjunct Use During Endodontic Therapy Among Dental Professionals in Jeddah, Saudi Arabia: A Cross-Sectional Study

Introduction  Chemical irrigation is a crucial component of endodontic therapy, and irrigation adjuncts increase the efficiency of non-surgical root canal system disinfection, reduce microbial loads, and enhance the penetration of irrigants throughout the root canal system. This study aimed to determine the current trends in chemical irrigation and its adjunct use during root canal therapy by general dental practitioners (GDPs) and endodontic specialists in both government and private sectors in the city of Jeddah, Saudi Arabia. Methods This cross-sectional study used a self-administered survey sent to GDPs and endodontic specialists in both government and private sectors in the city of Jeddah, Saudi Arabia. Responses were accepted from November 2019 till May 2020. The survey was randomly distributed to consenting participants. The results are presented using descriptive statistics. Results A total of 302 participants responded to the survey, with a 44% response rate. The majority of responses were from GDPs (54%), while 46% were from endodontic specialists. Regarding the workplace, 59% of respondents were public sector professionals, 25% were private sector professionals, and 16% were both public and private sector professionals. Around 30% of the respondents used sodium hypochlorite (NaOCI) as their primary irrigation solution during root canal treatment, with 52% using it at its full-strength concentration and 18% and 17% preferring to use it in combination with Ethylenediaminetetraacetic acid (EDTA) only or EDTA and saline, respectively. When asked to rank the reasons for choosing their irrigant of choice during therapy; antibacterial capability and tissue dissolution were the most crucial factors to 80% and 57% of participants, respectively. Half of the respondents irrigated the canal to 2 mm from the apex and 21% irrigated to 1 mm from the apex. Three-quarters of participants aimed to remove the smear layer during root canal treatment. Only 47% of respondents used adjuncts to irrigation, and 71% reported that their choice of irrigation solution would differ depending on whether the apex is open or closed. Conclusion Most respondents used full-strength NaOCI concentration as the main irrigation solution and routinely removed the smear layer during root canal treatment. Only 47% of respondents used irrigation adjuncts such as ultrasonics.

Micro-CT evaluation of four final irrigation protocols on hard-tissue debris removal from mesial roots of mandibular molars containing isthmus

OBJECTIVES

To evaluate by means of microcomputed tomography (micro-CT), the efficacy of four final irrigation protocols in the removal of hard-tissue debris (HTD) in mesial roots of mandibular molars containing isthmus.

MATERIALS AND METHODS

Forty standardized mesial roots of extracted mandibular molars presenting isthmus were selected. The root canals were prepared and randomly divided into 4 groups (n = 10): EA, EndoActivator (Dentsply Sirona); EC, Easy Clean (Easy Dental Equipment, Belo Horizonte, Brazil); XPF, XP-Endo Finisher (FKG Dentaire, La Chaus-de Fonds, Switzerland); and PUI, passive ultrasonic irrigation using Irrisafe tip (Satelec Acteon, Merignac, France). Each final irrigation protocol was performed in two cycles (60 s), using, respectively, 2.5% sodium hypochlorite and 17% EDTA. Micro-CT scans were obtained pre-operatory, post-preparation, and post-irrigation. The percentage of HTD reduction was calculated. Data was analyzed statistically (ANOVA and Kruskal-Wallis, significance set at 5%).

RESULTS

The percentage of HTD reduction was greatest for the XPF group (77.92%), followed by EA (62.92%), PUI (47.48%), and EC (32.65%). Statistical differences (p < .05) were found between XPF and EC only. A significant difference (p < .05) was found between XPF and EC in all thirds and between PUI and EC in the middle third.

CONCLUSIONS

XPF, EA, and PUI were similarly effective in HTD reduction. However, none of the evaluated protocols was able to completely remove all the debris.

CLINICAL RELEVANCE

Final irrigation protocols aim to clean the canal complexities that are not addressed by the shaping procedures. Micro-CT allowed to assess the removal of hard-tissue debris in the isthmus and canals of mandibular molars.

Efficacy of sonic and ultrasonic activation during endodontic treatment: a Meta-analysis of in vitro studies

OBJECTIVE

To ensure a successful endodontic treatment, it is important to have a proper disinfection of the root canal. The current study compares the root canal cleanliness and smear layer score between sonic and ultrasonic activation.

METHOD

Systematic literature review was implemented, using 12 databases. All in vitro studies comparing the efficacy of sonic and ultrasonic activation and reporting at least one outcome of interest were included.

RESULTS

At the apical level, pooling the data in the random-effects model (I²=64%, p = .1) revealed a statistically significant lower smear layer score within the sonic activation group (MD-0.48; 95% CI-0.92, -0.04; p = .03). Furthermore, there was a statistically significant lower push-out bond strength value among the sonic group, in contrast to the ultrasonic group at the middle (MD-0.69; 95% CI-1.13, -0.25; p = .002) and at the apical levels (MD-0.78; 95% CI-1.09, -0.46; p < .0001) of the root canal.

CONCLUSIONS

Sonic activation accomplished advancement relative to ultrasonic agitation in removing the smear layer, while ultrasonic activation resulted in significant cohesion between the sealers and the dentine tubules, decreasing the vulnerability of apical leakage and tooth fracture.

Efficacy of Different Endodontic Irrigant Activation Systems on Smear Layer Removal and Canal Cleanliness: Comparative Scanning Electron Microscopic Study

AIM: This study assessed the effectiveness of 5 different irrigant activation systems on canal cleanliness and removal of smear layer from root canals. METHODS: A total of 110 mandibular premolars with straight root canal were assigned to five groups (n = 20): conventional needle irrigation, passive ultrasonic activation, sonic activation with EndoActivator, negative apical pressure EndoVac (EV), or EDDY system, besides a control group (n = 10). All teeth were prepared to size 40, and irrigated with NaOCl (5.25%) according to the respective technique. Roots were split longitudinally and subjected to scanning electron microscopic analysis. The presence of smear layer and debris was evaluated using 5-grade scoring systems with ×1000 and ×400 magnification, respectively. Data were analyzed at 5%. RESULTS: Regarding the smear layer, activation with EV and ED was significantly more effective than other activation groups (p < 0.05). Activation of the irrigant significantly improved removal of debris (p < 0.05). CONCLUSION: No activation technique was able to eliminate smear layer and debris completely from root canals, nevertheless, EDDY is significantly better in removing debris and smear layer from the apical third of the canal.

Removal of Accumulated Hard Tissue Debris (AHTD) from Root Canals with an Electric Current Device: A MicroCT Preliminary Report

In modern endodontics, removal of accumulated hard tissue debris (AHTD) from root canals is requested. In the last decade, different irrigating solutions and activation methods have been successfully tested. Sonic activation has been shown to be effective in the removal of AHTD. Electric current has been tested before in restorative dentistry, but not in endodontics. An experimental electric current delivering device was compared in the removal of AHTD, using microCT analyses. Fifteen single-rooted teeth were shaped with TruNatomy system endodontic files and divided into three groups: negative control group: specimens underwent no activation; EA group: specimens were activated with EndoActivator (EA); EB group: specimens were activated with ElectroBond (EB). The 2D images, 3D images and morphometric analysis from the microCT showed a statistically significant increased AHTD removal when EB was used. Results of the present preliminary study showed that the irrigant activation with ElectroBond is encouraging when compared to EndoActivator along the entire root canal system. The AHTD was significantly statistically reduced, validating the clinical use of electric fields in endodontics.

Debridement Ability of TruNatomy, S-One Plus, and Other Single File Systems

BACKGROUND: Rotary nickel titanium instrument are an essential part of endodontic treatment, it is important to compare the root canal cleaning ability of these instruments. AIM: This study aimed to compare the amount of smear and debris layer remained following the use of four rotary instruments with an irrigant solution: TruNatomy (TRN), Protaper Next (PTN), S-One Plus and Wave One Gold (WOG). METHODS: A total of 80 extracted mandibular premolars were used and decoronated to the cemento-enamel junction. The roots were randomly divided into four groups of 20 specimens each. The roots were instrumented according to the manufacturer’s instructions of each file, the root canals were irrigated with sodium hypochlorite (NaOCl), Ethylene-diaminete-traacetic acid (EDTA) and Normal saline with each file use, two grooves were prepared on the buccal and lingual surfaces by disc to facilitate vertical splitting with a chisel. The presence of the smear layer and the debris layer were evaluated under Scanning Electron Microscope. RESULTS: Trunatomy remove the smear layer substantially better than PTN and S-one Plus. Wave one gold significantly removes smear layer better PTN. The amount of debris remained in TruNatomy group was significantly lower than other groups, all experimental files significantly removes the smear layer and debris layer better in the middle and coronal thirds compared to apical third. CONCLUSION: TruNatomy showed better cleaning capacity than all other experimental groups and all experimental groups demonstrated better cleanliness at the coronal and middle third of the roots.

Comparison of the efficacy of sonic irrigation and conventional syringe irrigation in the removal of curcumin and triple antibiotic paste from root canals

Background. The present study aimed to compare the efficacy of sonic irrigation and conventional syringe irrigation (CSI) in terms of curcumin (CUR) and triple antibiotic paste (TAP) removal from a standardized groove artificially created in root canals.

Methods. The root canals of 72 anterior maxillary teeth were prepared using the Reciproc system to size R50. The teeth were split longitudinally, and a standardized groove was created in the apical region of one root half. The standardized grooves were filled with CUR or TAP with the exclusion of six teeth that served as the negative control group, and then the root halves were reassembled. The teeth were divided into two subgroups according to the irrigation protocols used: sonic activation with EndoActivator (EA) or CSI (n=15). After the removal of the medicament, the residual medicament was assessed under a stereomicroscope. Kruskal-Wallis and Mann-Whitney U tests were used for statistical analyses (P = 0.05).

Results. The EA sonic activation method was significantly more efficient in removing CUR medicament from the root canals. Considering the medicament types, more CUR than TAP was removed from the root canals using both CSI and the EA (sonic activation) system (P < 0.05).

Conclusion. As compared with CSI, the EA was not significantly more efficient in removing TAP, but it was significantly more effective than CSI in removing CUR.

In vitro evaluation of efficacy of two endodontic sonic-powered irrigant agitation systems in killing single-species intracanal biofilms

OBJECTIVE

To evaluate the efficacy of two sonic-powered irrigation systems, EDDY and EndoActivator, in killing intracanal biofilms.

METHODS

Eighty-three instrumented, autoclaved single-rooted human premolars were inoculated with Enterococcus faecalis (ATCC-29212) for 21 days to generate mature, single-species biofilms. The teeth were devided into four groups: irrigation with saline (N = 11); irrigation with 2% NaOCl without agitation (N = 24); irrigation with 2% NaOCl with agitation by the EndoActivaor (N = 24); irrigation with 2% NaOCl with agitation by the EDDY (N = 24). Colony-forming unit (CFU) counts and XTT assay were used to evaluate bacterial load. Additional teeth were split into root-halves for fluorescence staining to examine the percentages of live/dead bacteria in the dentinal tubules present in different canal locations (coronal, mid-root and apical portions).

RESULTS

Agitation of 2% NaOCl by EDDY or EndoActivator reduced bacteria load more proficiently than the use of 2%NaOCl without agitation (p < 0.05). No significant difference was detected between the two sonic-powered irrigant agitation systems (p > 0.05). Confocal laser scanning microscopy indicated that both devices had better intratubular bacteria killing efficacy than the use of 2% NaOCl only in all parts of the canal space (p < 0.05), with no significant difference detected between EDDY and EndoActivator (p > 0.05). Elimination of intracanal and intratubular bacteria were less efficient in the apical portion of the canal space for all experimental groups.

CONCLUSION

The two sonic-powered irrigant activation systems demonstrated comparable intracanal bacteria reduction efficacy when 2% NaOCl was used for disinfecting E. faecalis biofilms in single-rooted teeth.

CLINICAL SIGNIFICANCE

With the use of 2% NaOCl as irrigant, the EDDY and EndoActivator sonic-powered irrigant agitation systems have improved and equivalent intracanal bacteria reduction efficacy but are incapable of completely killing all bacteria that resided within the dentinal tubules of root canals.

Effect of Sonic Activation on Push-Out Bond Strength of Fiber Post: An In Vitro Study

This study aimed to evaluate the effectiveness of conventional and sonic activation techniques on push-out bond strength of fiber post cemented with two different monomers containing self-adhesive resin cement (SARC). Four groups (n = 19 each) were made based on the type of SARC (Rely X U200 and Panavia SA) and technique (conventional and sonic activation). After placing the fiber post, each root was sectioned into 2 mm coronal, middle, and apical portions, and a push-out bond strength test was performed using a universal testing machine. The least push-out bond strength (13.0 ± 0.9 MPa) was found in Rely X U200 conventional technique and highest with Panavia SA sonic activation technique (15.4 ± 0.9 MPa). A significant difference was found in push-out bond strength at coronal (p = 0.002), middle (p = 0.002), and apical (p = 0.001) root sections using Rely X U200 cement with sonic activation as compared to the conventional technique. However, no difference (p > 0.05) was noticed between conventional and sonic activation techniques in Panavia SA cement at any root level. Sonic activation can be used as an adjunct with a manual technique to increase bond strength. However, it was noted that 10-MDP monomer containing SARC performed well regardless of techniques.

Efficiency of Different Endodontic Irrigation and Activation Systems, Self-Adjusting File Instrumentation/Irrigation System, and XP-Endo Finisher in Removal of the Intracanal Smear Layer: An Ex vivo Scanning Electron Microscope Study

Aim:

This ex vivo study was designed to evaluate and compare different endodontic irrigation and activation systems, the self-adjusting file (SAF) instrumentation/irrigation system, and XP-endo finisher for removal of intracanal smear layer.

Materials and Methods:

Fifty recently extracted, noncarious human intact single-rooted premolars were selected and divided into five groups (n = 10) according to the root canal irrigation systems; syringe and needle irrigation, passive ultrasonic irrigation (PUI), EndoVac irrigation system, SAF system, and XP-endo finisher. All groups were prepared to apical size F4 file except for the SAF group which was prepared to apical size 20 K-file and then instrumented with the SAF file. Each sample was subjected to final irrigation using different irrigation/activation systems. After splitting the samples, one half of each root was selected for examination under scanning electron microscope. The irrigation systems were compared using the Fisher's exact test with significance set at P < 0.05.

Results:

In the coronal part, there was no difference among the groups. In the mid-root section, the results of the PUI, EndoVac, SAF, and XP-endo finisher groups tended to be better than syringe and needle irrigation, but the difference was not significant. The apical part of the canal, the SAF system, and XP-endo finisher group seemed to be cleaner than those of the EndoVac group, but this difference was not significant.

Conclusions:

Within the limitations of the present study, SAF system and XP-endo finisher group cleaned the apical part of the canal more efficiently than EndoVac, PUI, and syringe and needle irrigation.

Micro-cleanliness of Hard Tissue Debris After Advanced Irrigation and Comparison Between EndoVac and XP-endo Finisher: A Microcomputed Tomographic Study

Introduction:

Conventional irrigation techniques do not remove debris adequately. The remaining tissue debris cause infection inside the root canal and may also affect the seal of the root canal. The study aimed to compare the ability of EndoVac (EV) with XP-endo finisher (XPF) in debris removal using micro-CT analysis.

Materials and Methods:

We used 12 lower first permanent molar human teeth for this study. The root canals were instrumented using a small TF adaptive system. Then, the volume of debris was calculated. Teeth were divided into two groups, according to advanced irrigation methods, with six teeth per group: EV group and XPF group. The volume of debris was calculated again. The paired-sample t-test was used to compare the volume of the debris before and after the use of advanced irrigation methods with the statistical significance of P < 0.05. The percentage of debris reduction was also calculated.

Results:

Both EV and XPF showed a significant decrease of debris in the mesial canals (P < 0.05), whereas EV only showed a significant reduction of debris in the distal canals.

Conclusion:

Both EV and XPF were able to significantly reduce debris after instrumentation in the mesial canals of lower first mandibular molars.

Clinical Significance:

The study provides insight into the recent advanced methods used in debris removal and canal disinfection.

Debris Removal Using a Hydroxyapatite Nanoparticle-Containing Solution (Vector Polish) with Sonic or Ultrasonic Agitation

Chemomechanical preparation of the root canal system is considered to be the most important part of root canal treatment, including both mechanical removal of tissue remnants and dentine chips, and chemical elimination of biofilm and microorganisms. A number of different solutions and agitation techniques have been proposed for that purpose. It was the aim of the present study to investigate whether root canal cleanliness can be improved by using a hydroxyapatite nanoparticle-containing solution with and without sonic or ultrasonic agitation. Seventy-four single-rooted teeth were divided into four experimental groups (n = 15) and two control groups (n = 7). All teeth were split longitudinally and a groove and three holes were cut into the root canal wall and filled with dentinal debris. Final irrigation was performed using sodium hypochlorite or a hydroxyapatite nanoparticle-containing solution (Vector polish) activated with a sonically or an ultrasonically driven endodontic file. Two calibrated investigators rated the remaining debris using a four-score scale. The results were analyzed using a non-parametric test with α < 0.05. Sonic and ultrasonic irrigation with sodium hypochlorite cleaned the grooves and holes well from debris. The hydroxyapatite nanoparticles activated by a sonic file cleaned grooves and holes equally well. Ultrasonically activated nanoparticles performance was clearly inferior. The syringe control-group left large amounts of debris in grooves and holes. The use of the hydroxyapatite nanoparticles used in this study did not improve removal of debris.

PRILE 2021 guidelines for reporting laboratory studies in Endodontology: explanation and elaboration

Guidance to authors is needed to prevent their waste of talent, time and resources in writing manuscripts that will never be published in the highest-quality journals. Laboratory studies are probably the most common type of endodontic research projects because they make up the majority of manuscripts submitted for publication. Unfortunately, most of these manuscripts fail the peer-review process, primarily due to critical flaws in the reporting of the methods and results. Here, in order to guide authors, the Preferred Reporting Items for study Designs in Endodontology (PRIDE) team developed new reporting guidelines for laboratory-based studies: the Preferred Reporting Items for Laboratory studies in Endodontology (PRILE) 2021 guidelines. The PRILE 2021 guidelines were developed exclusively for the area of Endodontology by integrating and adapting the modified CONSORT checklist of items for reporting in vitro studies of dental materials and the Clinical and Laboratory Images in Publications (CLIP) principles. The process of developing the PRILE 2021 guidelines followed the recommendations of the Guidance for Developers of Health Research Reporting Guidelines. The aim of the current document is to provide authors with an explanation for each of the items in the PRILE 2021 checklist and flowchart with examples from the literature, and to provide advice from peer-reviewers and editors about how to solve each problem in manuscripts prior to their peer-review. The Preferred Reporting Items for study Designs in Endodontology (PRIDE) website (http://pride-endodonticguidelines.org/prile/) provides a link to the PRILE 2021 explanation and elaboration document as well as to the checklist and flowchart.

Root canal debridement by negative pressure irrigation, ultrasonically activated irrigation and their combination

Despite scientific evidence that root canal debridement is the cornerstone for successful treatment, the effectiveness of a combination of delivery and activation systems in cleaning root canals remains unknown. This study is the first to demonstrate the remaining pulp tissue in root canals after irrigation with various techniques such as positive pressure syringe-and-needle irrigation, ultrasonic activation, negative pressure irrigation and ultrasonic activation after negative pressure irrigation. The results showed that negative pressure irrigation alone and its combination with ultrasonic activation resulted in significantly superior effectiveness than positive pressure irrigation and ultrasonic activation alone in the apical-third of root canals.

FESEM evaluation of smear layer removal from conservatively shaped canals: laser activated irrigation (PIPS and SWEEPS) compared to sonic and passive ultrasonic activation-an ex vivo study

Background

Irrigation of the pulp space is a mandatory step to get rid of all its organic and inorganic content. Activation of the irrigants play a key role in the era of minimally invasive endodontics. The aim of this study was to assess the effectiveness of different irrigants activation methods in removing the smear layer at 1, 3, 5 and 8 mm from the apex from conservatively shaped canals.

Methods

Eighty-five human mandibular premolars were selected. Specimens were shaped to TruShape 25/.06 and divided into 5 groups (1 control and 4 test groups) according to the final activation technique (EndoActivator, EA), Ultrasonic (EndoUltra, PUI) and Laser (PIPS and SWEEPS). EDTA (Ethylenediaminetetraacetic acid) followed by NaOCl (Sodium Hypochlorite) and again EDTA were activated for each test group. Specimens were then split longitudinally and observed by Field Emission Scanning Electron Microscopy (FESEM). Blinded evaluation of the presence of smear layer was performed at 1000X magnification, according to a 5-score index system. Comparison between groups were analysed statistically using the Kruskal–Wallis non-parametric analysis of variance. Bonferroni multiple comparison tests were used.

Results

At 1 mm only PIPS and SWEEPS performed better than the control group. At 3, 5 and 8 mm from the apex, every activation technique showed statistically significant reduction of smear layer when compared to the control group. PIPS and SWEEPS obtained better cleanliness result compared to EA, while only PIPS was superior to PUI in terms of cleanliness.

Conclusions

PIPS and SWEEPS showed the best results in conservative canal preparations. Nowadays, contemporary rotary instruments allow fast and minimally invasive shaping of the endodontic space. In this scenario irrigants’ activation may be regarded as a mandatory step to a favourable clinical outcome.

Smear layer removal by passive ultrasonic irrigation and 2 new mechanical methods for activation of the chelating solution

Objectives

The aim of this study was to compare smear layer removal by conventional application (CA), passive ultrasonic irrigation (PUI), EasyClean (EC), and XP-Endo Finisher (XPF), using 17% ethylenediaminetetraacetic acid (EDTA) after chemomechanical preparation, as evaluated with scanning electron microscopy (SEM).

Materials and Methods

Forty-five single-rooted human mandibular premolars were selected for this study. After chemomechanical preparation, the teeth were randomly divided into 5 groups according to the protocol for smear layer removal, as follows: G1 (control): CA of distilled water; G2 (CA): CA of 17% EDTA; G3 (PUI): 17% EDTA activated by PUI; G4 (EC): 17% EDTA activated by EC; and G5 (XPF): 17% EDTA activated by XPF. SEM images (×1,000) were obtained from each root third and scored by 3 examiners. Data were evaluated using the Kruskal-Wallis and Dunn tests (p < 0.05).

Results

In the apical third, there were no statistically significant differences among the groups (p > 0.05). In the cervical and middle thirds, the experimental groups performed better than the control group (p < 0.05); however, G2 presented better results than G3, G4, and G5 (p < 0.05), which showed no differences among one another (p > 0.05).

Conclusions

No irrigation method was able to completely remove the smear layer, especially in the apical third. Using CA for the chelating solution performed better than any form of activation.

Heated distilled water with or without continuous ultrasonic irrigation improves final irrigation efficacy and reduces dentine erosion

OBJECTIVES

The present study evaluated the effects of using heated distilled water (HDW), with or without continuous ultrasonic irrigation (CUI), on smear layer removal and deterioration of root dentine microstructure.

MATERIALS AND METHODS

After chemomechanical preparation, 60 human teeth were longitudinally cleaved into two halves for smear layer quantification at the cervical-third, middle-third and apical root-third of the canal space. After reassembly, the root canals were irrigated with 17 % EDTA, followed by one of the six final irrigation protocols (n = 10) - G1: conventional irrigation (CI)+NaOCl at 25 °C; G2: NaOCl at 25 °C + CUI; G3: CI with DW at 25 °C; G4: DW at 25 °C + CUI; G5: CI + HDW at 65 °C; G6: HDW at 65 °C + CUI. Tooth-halves were processed and examined by scanning electron microscopy. The percentage of opened dentinal tubules in the irrigated areas of the canal space was expressed as a percentage of the total surface area. Dentine erosion was classified by numeric scores. Smear layer removal was analysed with ANOVA and Student-Newman-Keuls tests; dentine erosion was analysed with Cohran-Mantel-Haenstel statistic (α = 0.05).

RESULTS

The cervical-third had a higher percentage of open dentinal tubules for all groups (p < 0.05). In G2, the middle-third had a lower percentage of open tubules, which was significantly different from the other groups (p < 0.05). Groups that utilised NaOCl as the final irrigant had more extensive erosion when CUI was used.

CONCLUSION

Heated distilled water, with or without CUI, was as efficient as 1 % NaOCl in the final cleaning of the instrumented canal space. The use of HDW produces less extensive dentine erosion.

CLINICAL SIGNIFICANCE

Heated distilled water removes smear layers with less deleterious effects on dentine microstructure and may be considered a final irrigant after mechanical preparation and EDTA chelation.

In Vitro Evaluation of Different Irrigation Protocols on Intracanal Smear Layer Removal in Teeth with or without Pre-Endodontic Proximal Wall Restoration

To investigate the influence of pre-endodontic coronal wall restoration on smear layer removal during different root canal irrigation strategies, single-root premolars were prepared with a mesio-occlusal cavity. Half were left untreated (G1), while the mesial walls of the remaining half were reconstructed using a resin composite (G2). The specimens were divided into control (ctrl) groups, which used the conventional needle irrigation method, and four experimental subgroups according to irrigation strategy: Sonic activation using the Endoactivator, sonic activation using the EQ-S, mechanical activation using the XP-Endo finisher, and ultrasonic activation using the EndoUltra. Smear layer removal was assessed through SEM and the results were statistically analyzed. At the coronal and middle thirds, no significant difference (p > 0.05) was detected for G1 and G2, except for the control subgroups (G1ctrl vs G2 ctrl) at the middle third. At the apical third, the smear layer removal was significantly greater for G2 than G1. In G1, both at the middle and apical level, EQ-S and EndoUltra showed greater smear layer removal (p < 0.05) compared to the others G1 subgroups. In G2, at the apical level, the EQ-S and EndoUltra were the most effective in smear layer removal. Pre-endodontic coronal wall restoration may improve the smear layer removal during root canal irrigation.

Micro-computed Tomographic Assessment of Supplementary Cleaning Techniques for Removing Bioceramic Sealer and Gutta-percha in Oval Canals

INTRODUCTION

The aim of this study was to conduct a micro-computed tomographic assessment of the effectiveness of 3 supplementary cleaning techniques in reducing the residual volume of gutta-percha and a bioceramic sealer after performing endodontic retreatment procedures in teeth with oval canals.

METHODS

Thirty-six mandibular premolars were instrumented with the ProTaper Next system (instruments X1-X3; Dentsply Maillefer, Ballaigues, Switzerland) and filled with gutta-percha and Bio-C Sealer (Angelus, Londrina, PR, Brazil) using the single-cone technique. The teeth were reinstrumented with the Reciproc R40 instrument (VDW, Munich, Germany) and divided into 3 groups according to the supplementary cleaning technique used (n = 12): ultrasonic-assisted irrigation (UAI), EndoActivator (Dentsply Tulsa Dental Specialties, Tulsa, OK) irrigation (EAI), or the XP-endo Finisher R system (XPR; FKG Dentaire, La Chaux-de-Fonds, Switzerland). Micro-computed tomographic imaging was used to quantify the residual volume of filling material. One-way analysis of variance complemented by the Tukey test was used to perform the statistical analysis (P < .05).

RESULTS

Significant reductions were obtained in the residual filling material after supplementary cleaning (P < .05). XPR (47.5%) led to significantly greater (P < .05) filling material removal than UAI (16.6%) or EAI (22.6%). The removal values of the 2 latter systems were not significantly different.

CONCLUSIONS

XPR was more effective than UAI and EAI in removing filling material in mandibular premolars with oval canals. None of the tested supplementary cleaning techniques completely removed the residual filling material.

Debris and Smear Layer Removal from Oval Root Canals Comparing XP-Endo Finisher, EndoActivator, and Manual Irrigation: A SEM Evaluation

Objective  This study aimed to assess and compare XP-Endo Finisher (XP) cleaning efficiency with respect to the amount of remaining debris and smear layer versus Max-I-Probe needle (CI), EndoActivator device (EA), and combination of XP-Endo Finisher file with EndoActivator device (XP+EA) in oval root canals.

Materials and Methods  This in vitro study was performed on 36 extracted single root/canal mandibular premolars. Radiographic images were taken in buccolingual and mesiodistal projections to evaluate the shape of the root canal and determine whether it met exclusion criteria. All teeth were decoronated and prepared using Reciproc (R40). The samples were divided randomly into four groups: CI, EA, XP, and XP + EA. The root canals were irrigated with 5 mL of 17% EDTA and 2.5% NaOCl, respectively. Apart from the CI group, both solutions were activated by using the tested techniques for 1 minute.

The teeth were split longitudinally, and the best visible identified sections of the roots were used as the representing samples for scanning electron microscope (SEM) evaluation. Each half was divided into the following three parts: 1 mm from the anatomic apex and a standardized photomicrograph with 500x and 1500x magnifications for debris and smear layer were obtained. A five-grade scoring system was utilized to quantify the results at the coronal, middle, and apical regions. Statistical analysis was performed by using the Kruskal–Wallis and Mann–Whitney U tests.

Results  Group differences in debris and smear layer scores were found statistically significant for all locations as well as for overall assessment, except for the coronal third. Intragroup comparison of debris and smear layer in CI, EA, and XP had the minimum score at the middle third, with no significant difference compared with the coronal and apical thirds. XP + EA had less debris and smear layer score at the coronal third, significantly different from apical third.

CI and EA had less debris and smear layer compared with XP and XP + EA at all locations with a significant difference at the middle and apical third ( p < 0.05).

Conclusion  EA and CI showed less debris and smear layer than XP and XP + EA in the middle and apical third. The use of the XP in conjunction with the present irrigation protocol failed to have debris-free dentin surface in the apical portion of most of the root canals.

Quantitative analysis of SmearOFF and different irrigation activation techniques on removal of smear layer: A scanning electron microscope study

The aim of this study was to evaluate the effectiveness of SmearOFF solution on smear layer removal by using different irrigation activation techniques. One hundred and twenty mandibular premolars were decoronated, and instrumented with Reciproc up to size 50. Then, the specimens were divided into 6 groups according to the final irrigation activation technique: Group 1: SmearOFF + Conventional syringe irrigation (CSI); Group 2: SmearOFF + Sonic activation (SA); Group 3: SmearOFF + Passive ultrasonic activation (PUA); Group 4:17% EDTA + CSI; Group 5:17% EDTA + SA, and Group 6:17% EDTA + PUA. Teeth were split longitudinally, and specimens were observed under scanning electron microscope. Images were taken from the coronal, middle, and apical thirds of the teeth with 1,000× magnification and analyzed using ImageJ program to calculate total open dentinal tubule areas. Three-way ANOVA test was applied to reveal any significant differences among solutions, activation techniques and root thirds. There was no statistically significant difference among the groups in terms of irrigation solutions (p > .05). There was a statistically significant difference between PUA and CSI groups (p < .05). However, no significant difference was observed between PUA and SA, or between SA and CSI (p > .05). All experimental procedures were most effective in the middle region of the root, followed by cervical and apical thirds (p < .05). PUA showed higher efficacy in smear layer removal compared with CSI. SmearOFF and 17% EDTA showed similar results. The best results in removing smear layer were obtained in the middle region of the root.

Analysis of the smear layer generated by different activation systems: an in vitro study

OBJECTIVES

To evaluate via scanning electron microscopy the amount of smear layer generated during the use of sonic and ultrasonic activation systems with standardized short-term intentional contacts with the canal walls.

METHODOLOGY

Seventy single-root human teeth were randomly assigned to 2 control (n = 5 each): NC (negative control), PC (positive control) and four experimental groups (n = 15 each): NC (negative control), PC (positive control), G1 (passive ultrasonic irrigation with Irrisafe), G2 (ultrasonic irrigation with EndoUltra), G3 (sonic irrigation with Endoactivator), G4 (sonic irrigation with Eddy). Samples were instrumented with ProTaper Next®. An irrigation protocol with sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) was followed for both PC and the experimental groups. Standardized intentional contacts were made in the mesial walls during 5 s at WL - 2 mm in all experimental groups. Two calibrated evaluators scored the smear layer generated with an ordinal scale by scanning electron microscopy. The weighted kappa coefficient (K_w) was calculated to determine the inter-observer agreement. Post-consensus ordinal data were analyzed using the ordinal (linear) chi-square test.

RESULTS

When the agitation file is in contact with dentine walls, Irrisafe® significantly generated the least amount of smear layer in the coronal third (p < 0.05). Both in the middle and apical third, activation with Irrisafe® also showed statistically significant better results than Eddy™ and EndoUltra®. Endoactivator® showed significant better results than EndoUltra® and Eddy™ in the apical third (p < 0.05).

CONCLUSIONS

Irrisafe generated the least amount of smear layer in the entire canal and similar to Endoactivator in the apical third when the agitation file is in contact with dentine walls.

CLINICAL RELEVANCE

The smear layer is generated during activation. It is common to apply irrigation protocols where after the removal of the smear layer using chelants, a final rinse and activation is carried out but there are no previous studies analyzing the possible creation of a new smear layer with this final activation.

Evaluation of smear layer and debris removal by stepwise intraoperative activation (SIA) of sodium hypochlorite

OBJECTIVES

To evaluate the efficacy of a stepwise intraoperative activation (SIA) of irrigants during and after the instrumentation compared with that of a conventional activation (CA) performed only after the instrumentation to remove smear layer and debris using different activation devices.

MATERIALS AND METHODS

A total of 70 single-rooted teeth were divided into a control group (no activation, n = 10) and two different experimental groups according to the irrigant activation protocol used: group 1 (CA), in which sodium hypochlorite was activated only after the use of the last mechanical file, and group 2 (SIA), in which activation was performed during and after the instrumentation. The two groups were divided into 3 subgroups according to the activation device used (n = 10): passive ultrasonic irrigation (PUI, subgroup a), EndoActivator (EA, subgroup b), and EDDY (subgroup c). The roots were split longitudinally and observed using scanning electron microscopy (SEM) to evaluate the presence of debris and smear layer, and the results were statistically analyzed.

RESULTS

All activation protocols and devices were more effective than control group in removing smear layer and debris from all root canal thirds (P < 0.05), except for CA-EA (group 1b) in the apical third. In the apical third, SIA was found to be more effective than CA (P < 0.05) to remove smear layer and residual debris when PUI was used, to remove the smear layer when EA was used (P < 0.05), and to remove residual debris when EDDY was used (P < 0.05). PUI and EDDY removed statistically more smear layer and debris than EA in the apical third (P < 0.05).

CONCLUSIONS

The SIA technique improved the smear layer and debris removal from the apical third and debris removal from the coronal third, and PUI and EDDY were more effective than EA in the apical third.

CLINICAL RELEVANCE

The stepwise intraoperative activation (SIA) technique may increase smear layer and debris removal.

Can Irrigant Agitation Lead to the Formation of a Smear Layer?

INTRODUCTION

This study aimed to assess whether ultrasonic activation (UA) or the EasyClean (EC; BassiEndo, Belo Horizonte, BH, Brazil) or EDDY (ED; VDW, Munich, Germany) systems used to promote agitation of the irrigating solutions during the final irrigation step can lead to smear layer formation in the apical third of the root canal.

METHODS

Thirteen premolars were instrumented with the Reciproc R40 file (VDW) and embedded in silicone, forming a closed irrigation/aspiration system. The teeth were cleaved, and 4 indentations were made on the inner buccal wall of the canal to standardize the observation sites. All the specimens were cleaned in an ultrasonic bath and evaluated under environmental scanning electron microscopy, thus constituting the control group. The same specimens were reassembled, submitted to final irrigation using UA or the ED or EC systems, and classified using a 4-level scoring system. The data were analyzed using the kappa, Pearson, and Kruskal-Wallis tests (P < .05).

RESULTS

Smear layer formation occurred in all of the experimental groups and at all apical levels. At 3 and 4 mm, all of the experimental groups had significantly higher levels of smear layer formation than the control group. At 2 mm, the level of smear layer formation in the UA group was significantly higher than that of the control group, and there were no significant differences among the EC, ED, and control groups. At 1 mm, there were no significant differences between the ED and control groups, and the levels of smear layer formation in the EC and UA groups were significantly higher than that of the control group. There were no significant differences between the ED and EC groups at any of the apical levels.

CONCLUSIONS

The smear layer formation occurred in all of the specimens submitted to final irrigation, irrespective of the technique used.

Comparison of Five Different Irrigation Techniques on Smear Layer Removal in Apical Thirds of Root Canals of Mandibular First Premolar: A Scanning Electron Microscopic Study

Aim:

This study was conducted to compare smear layer removal by five different irrigation techniques—conventional needle irrigation (CI), manual dynamic activation (MDA), passive ultrasonic irrigation (PUI), sonic irrigation (SI), and negative apical pressure (NAP).

Materials and Methods:

Fifty freshly extracted mandibular first premolars were cleaned and shaped by One Curve rotary files and 3% sodium hypochlorite and 17% ethylenediaminetetraacetic acid. The samples were divided into five equal groups (n = 10), according to the final irrigation activation technique: Group I, CI; Group II, MDA; Group III, PUI; Group IV, SI; and Group V, NAP. The samples were prepared and observed under a scanning electron microscope. The photomicrographs were recorded and evaluated with a scoring system.

Results:

Group I and Group II had the highest scores, which showed a statistically significant difference between the other groups (P < 0.05). This was followed by PUI, NAP, and SI.

Conclusion:

Final irrigation activation with SI and NAP resulted in the better removal of smear layer when compared to that with other groups.

Endodontic irrigants: Different methods to improve efficacy and related problems

Shaping and cleaning a root canal system along with the preservation of the surrounding periodontal tissues are the principal goals of an endodontic treatment. While most of the attention is paid to the mechanical aspects of a root canal treatment, an essential feature of it is the irrigation. All over the years, many materials have been used to clean the root canal of a tooth, and certainly, the sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid solutions are the most used and most reliable ones. Putting them inside of a canal is mostly done using a normal syringe, but many techniques have been involved in this process, including the use of sonic/ultrasonic instruments, the use of shaping files, and even laser, to increase the efficacy of irrigant solutions, especially of NaOCl one. Each one of this technique faces some disadvantages, just as the vapor lock effect and the apical extrusion, and has a different action on features such as the reaction rate and the shear stress of an endodontic irrigant solution. In this narrative review, we describe the different features of many irrigant solutions and the different ways of upgrading their efficacy in the cleaning of a root canal system, with the use of tables to summarize the entire description, and drawing the readers' attention to a photographic illustration for a better understanding of the topic.

Antimicrobial efficacy of cordless sonic or ultrasonic devices on Enterococcus faecalis-infected root canals

AIM

The aim of the present study was to evaluate the immediate and residual antimicrobial activity of cordless sonic or ultrasonic devices on Enterococcus faecalis (E faecalis)-infected teeth.

METHODS

A total of 140 single-rooted extracted teeth with E faecalis were grouped as follows (N = 15): conventional syringe irrigation with 3% sodium hypochlorite activated by ultrasonic device (group 1) or cordless ultrasonic device (group 2), EndoActivator (group 3) or without activation (group 4), conventional syringe irrigation with sterile bi-distilled water and ultrasonic device (group 5), EndoUltra (group 6), EndoActivator (group 7), or without activation (group 8). The remaining 20 teeth were used for positive and negative controls. Colony-forming units (CFU) and turbidity were recorded from bacteriological samples taken before and after irrigation and after 24 hours of re-incubation. Data were statistically analyzed using Student's t test, Mann-Whitney test, Kruskal-Wallis test, and Dunn's multiple comparison tests (P < .05).

RESULTS

Groups 1 and 2 showed higher antimicrobial efficacy than groups 3 and 4 (P < .05). No bacteria reduction was found in groups 5-8 (P > .05). After 24 hours, regrowth of bacteria was not significantly different for all groups (P > .05).

CONCLUSIONS

Ultrasound produced lower CFU and turbidity after treatment and after re-incubation of 24 hours than sonic or no activation.

Comparison of bacterial removal from dentinal tubules with different irrigant agitation techniques: An in vitro study

Aim

This investigation was conducted to assess the ability of various irrigant agitation devices to eradicate Enterococcus faecalis from the dentinal tubules of extracted teeth.

Methodology

Fifty roots of extracted human teeth were instrumented to size 30 k with a 0.04 taper. The roots were autoclaved and then injected with E. faecalis. The canals were assigned to one of four intervention groups and disinfected using (A) standard needle irrigation, (B) EndoUltra® Ultrasonic Activator, (C) the EndoActivator system, or (D) EDDY sonic activation and to two control groups that were (E) treated with saline and (F) not inoculated with any bacteria. The roots were split in half, dyed with a LIVE/DEAD Back Light Bacterial Viability Kit, and then scanned with a confocal laser scanning microscope (CLSM) to identify live/dead bacteria in the dentinal tubules.

Results

CLSM images revealed differences among the groups. Both the EndoUltra® Ultrasonic Activator group and the EDDY group had a combination of dead and live bacteria, while the EndoActivator group had mostly dead bacteria, in contrast to single needle irrigation which had mostly live bacteria. Activation of the irrigating solution resulted in more dead bacteria than standard needle irrigation at the coronal, middle, and apical parts of the roots. Overall, the EndoActivator system was superior to all other techniques in reducing live bacteria within the root canal.

Conclusion

Activation of sodium hypochlorite with sonic and ultrasonic systems dramatically reduced live bacteria contamination in the dentinal tubules of infected root canals.

A chitosan-based irrigant improves the dislocation resistance of a mineral trioxide aggregate-resin hybrid root canal sealer

OBJECTIVES

To investigate the effectiveness of root canal irrigation with chitosan on the dislocation resistance of a root canal sealer (MTA Fillapex) in vitro, measured by the push-out bond strength test.

MATERIALS AND METHODS

Root canals of mandibular premolars (n = 57) were prepared using rotary files with 5.25% sodium hypochlorite as the irrigant during instrumentation. Following this, the specimens were randomly divided into three groups (n = 19) based on the final irrigant: group 1, 0.2% chitosan solution; group 2, 17% EDTA solution; group 3, saline. Three specimens from each group were analyzed using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). The remaining specimens of each group were divided into two subgroups (n = 8) based on the method of agitation of the final irrigants (chitosan/EDTA/saline): subgroup A, sonic (Endoactivator, Dentsply Maillefer); subgroup B, no activation (control). After irrigation, all specimens obturated with a commercial mineral trioxide aggregate-resin hybrid sealer (MTA Fillapex, Angelus, Londrina, Brazil). Dislocation resistance was measured using the push-out bond strength test after 3 weeks. The data were analyzed using Kruskal-Wallis test (P = 0.05).

RESULTS

Immaterial of the irrigant agitation, groups irrigated with chitosan showed significantly higher bond strength values than those irrigated with EDTA (P < 0.05). Groups irrigated with saline showed the least bond strength values (P < 0.05). When EDTA was used, sonic agitation significantly improved the bond strength of the sealer, compared to the control (P < 0.05). There was no significant difference between sonic agitation and the control when chitosan solution was used as the final irrigant (P > 0.05). The nitrogen/carbon ratio was significantly higher in chitosan groups compared to the control group (P < 0.05).

CONCLUSION

This study provides the first evidence that chitosan irrigation improves the dislocation resistance of MTA-resin hybrid root canal sealer, compared to EDTA and saline irrigation.

CLINICAL RELEVANCE

Chitosan-based irrigation has been previously shown to demonstrate anti-biofilm properties in the root canal. The present study demonstrates that chitosan can improve the bond strength of a root filling material, which may contribute to better sealing of the root canal system.

Effectiveness of different activated irrigation techniques on debris and smear layer removal from curved root canals: a SEM evaluation

This study evaluates the effectiveness of different activated irrigation techniques on removal of debris and smear layer from curved root canals. Ninety mandibular molars with a root canal curvature between 20 and 40 degrees were assigned to 4 groups (n = 20): syringe irrigation (SI), passive ultrasonic activation (PUI), sonic activation with EDDY (ED) or EndoActivator (EA) and a control group. Mesiobuccal root canals were prepared to size 40, 0.04 and irrigated with NaOCl (3%) according to the respective technique. Roots were split longitudinally and subjected to scanning electron microscopic analysis. Presence of debris and smear layer was evaluated using 5-grade scoring systems with 200× and 1000× magnification, respectively. Data were analysed with nonparametric analysis for ordinal longitudinal data (α = 5%). Activation of the irrigant significantly improved smear layer removal (P < 0.05). Regarding debris, only activation with EA and ED was significantly more effective than SI (P < 0.05). No activation technique was able to eliminate debris and smear layer completely from curved root canals.

Cleaning effectiveness of a nickel-titanium ultrasonic tip in ultrasonically activated irrigation: a SEM study

In endodontic treatment, regardless of the instrumentation technique, the presence of a smear layer covering contaminated dentin walls is always a concern. Thus, irrigation plays an essential role in reducing bacterial load. To enhance irrigation effectiveness, different ultrasonic activation methods and the use of different tips have been studied. This study assessed the cleaning capacity of the novel NiTi ultrasonic tip for smear layer removal using ultrasonically activated irrigation (UAI) with passive or continuous ultrasonic irrigation (PUI or CUI, respectively), compared with conventional irrigation. Forty-five single-rooted human mandibular premolars were decoronated to a standardized length of 16 mm. Instrumentation was performed using the Genius system up to size 50.04 and irrigated with 3% NaOCl. The specimens were divided into three groups (n = 15) according to the final irrigation activation technique: conventional irrigation (CI), as control group; PUI; and CUI, following the manufacturer's protocol. The samples were longitudinally cleaved and analyzed under a scanning electron microscope for smear layer removal according to a cleanliness score for the cervical, middle, and apical thirds. Data were evaluated by means of the Kruskal-Wallis and Tukey's tests, with a 5% level of significance. UAI enhanced cleaning compared to conventional irrigation, mainly at the apical third. CUI showed the best results, with statistically significant lower scores than PUI and CI (p < 0.05). Final irrigant activation with the NiTi tip showed better cleaning capacity than conventional irrigation. In addition, CUI resulted in better smear layer removal than PUI.

Scanning electron microscopy evaluation of debris and smear layer generated by two instruments used in reciprocating motion WaveOne Gold® and Reciproc Blue®

The aim was to evaluate debris and smear layer at 1, 3 and 5 mm from the foramen of single-file systems WaveOne Gold® and Reciproc Blue®. Thirty single-rooted teeth were prepared using one of the following NiTi instruments WaveOne Gold® and Reciproc Blue®. Root canals were observed under a scanning electron microscope. The presence of debris and smear layer at the apical third of root canals was evaluated. Data were analysed by Friedman and Wilcoxon tests. WaveOne Gold® produced significantly less debris and smear layer compared to Reciproc Blue®. However, the mean amount of debris was significantly different within distances for WaveOne Gold®, while no difference were observed for Reciproc Blue. The mean amount of smear layer was not significantly different within distances with WaveOne Gold® and Reciproc Blue®. Both systems showed debris and smear layer in the apical third; nevertheless, WaveOne Gold® showed better results.

Effectiveness of different irrigation systems in the presence of intracanal-separated file

The aim of this study was to evaluate conventional syringe irrigation and three different irrigant activation techniques' effectiveness for smear layer removal in the absence and presence of intracanal-separated file (SF) fragment. Mandibular anterior teeth (160 total) with single canal were used and each root canal preparation was finished with the ProTaper Universal F1. The samples were randomly divided into eight equal groups with n = 20 in each group. The Protaper Universal F3 file was used to simulate intracanal file separation in four groups. To remove the smear layer, final irrigation for each group was performed with conventional syringe irrigation (CSI), EndoActivator, Vibringe, and passive ultrasonic irrigation (PUI). The roots were divided into two longitudinal parts and evaluated with scanning electron microscopy, and two observers scored smear layers at 1, 2, and 3 mm away from the minor foramen. The data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests (p < .05). PUI significantly removed the smear layer better at all levels than other nonseparated file groups (p < .05). In the presence of intracanal SF, PUI had the most efficiency loss. Sonic techniques and CSI revealed statistically better smear layer removal efficiency than PUI at 3 mm level in the presence of SF (p < .05). The intragroup score analysis at all levels revealed that there were less smear layers at 3 mm than at 1 mm in all SF groups (p < .001). As a conclusion, sonic/ultrasonic methods did not yield better irrigant by-passing than CSI in the presence of intracanal SF.

Efficacy of sonic and ultrasonic irrigation devices in the removal of debris from canal irregularities in artificial root canals

OBJECTIVE

To evaluate the efficacy of different sonic and ultrasonic devices in the elimination of debris from canal irregularities in artificial root canals.

MATERIALS AND METHODS

A resin model of a transparent radicular canal filled with dentin debris was used. Five groups were tested, namely: Group 1 - ultrasonic insert 15.02; Group 2 - ultrasonic insert 25/25 IRRI K; Group 3 - ultrasonic insert 25/25 IRRI S; Group 4 - sonic insert 20/28 Eddy on a vibrating sonic air-scaler handpiece; Group 5 - 20.02 K-file inserted on a Safety M4 handpiece. Two different irrigants (5% sodium hypochlorite and 17% EDTA) and 3 different times of activation (20, 40, and 60 seconds) were tested. Means and standard deviations were calculated and statistically analyzed with the Kruskal-Wallis and Wilcoxon tests (p<0.05).

RESULTS

No statistically significant differences were found between the two irrigants used. Group 4 removed more debris than the other groups (p<0.05). Groups 1, 2, and 3 removed more debris than group 5 (p<0.05). A statistically significant difference (p<0.05) was found for the time of activation in all groups and at all canal levels, except between 40 and 60 seconds in group 4 at coronal and middle third level (p>0.05).

CONCLUSIONS

No significant differences were found between 5% sodium hypochlorite and 17% EDTA. When the time of activation rises, the dentin debris removal increases in all groups. Both sonic and ultrasonic activation demonstrate high capacity for dentin debris removal.

Effectiveness of irrigation strategies on the removal of the smear layer from root canal dentin

The aim of this study was to evaluate the removal of the smear layer by some commonly used (needle-and-syringe irrigation, sonic activation, ultrasonically activated irrigation) and new root canal irrigation strategies (negative pressure irrigation and polymer rotary file) using a novel approach by comparing pre- and post-experimental images. Prepared root canals (n = 50) were subjected to a split tooth model and divided into 5 groups (n = 10): (1) needle-and-syringe irrigation (control); (2) sonic activation (SA); (3) negative pressure irrigation with continuous warm activated irrigation and evacuation (CWA); (4) polymer finishing file (FF); (5) ultrasonically activated irrigation (UAI). Smear layer scores and percentage of open dentinal tubules (%ODT) were evaluated by 2 examiners before and after irrigation procedures, from the middle and apical thirds of the root canal, on scanning electron microscopic images. Data were analysed using Kruskal-Wallis and post hoc tests at P = 0.05. Needle-and-syringe irrigation (control) showed no significant difference (both smear score and %ODT) compared to the pre-experimental value (P > 0.05). All other groups showed lower smear scores and higher %ODT, compared to the control (P < 0.05). The lowest smear score and highest %ODT were observed in the CWA group, which was significantly different from all other groups (P < 0.05). SA group showed significantly higher smear scores and lower %ODT than FF or UAI (P < 0.05). CWA showed superior removal of smear layer in the middle and apical thirds of the root canal compared to the other irrigation strategies.