Effect of Different Agitation Techniques on the Penetration of Irrigant and Sealer into Dentinal Tubules

The effect of different irrigation activation methods on the penetration of the irrigation solution into the dentinal tubules in teeth with calcium hydroxide applied and oval-shaped canals: Confocal laser scanning microscope analysis

This study aimed to evaluate the efficacy of different irrigation techniques including standard needle irrigation (SNI), passive ultrasonic irrigation (PUI), EndoActivator (EA), XP-Endo Finisher (XPF), photon-induced photoacoustic streaming (PIPS), and shock wave enhanced emission photo-acoustic streaming (SWEEPS) systems on the penetration of irrigation solutions into dentinal tubules in teeth with calcium hydroxide (CH) applied and oval-shaped canals by confocal laser scanning microscope (CLSM). Ninety mandibular incisor teeth with oval-shaped canals were included in this study. After the preparation of teeth using Resiproc Blue R25 (VDW, Munich, Germany) canals were filled with a paste based on CH. The teeth were stored in 100% humidity at a temperature of 37°C for 14 days. According to the irrigation activation systems, the teeth were divided into six groups (n = 15); SNI, PUI, EA, XPF, PIPS, and SWEEPS. In each group, 3 irrigation/activation cycles of 20 s of irrigation and 20 s of activation were performed with the relevant activation method. The root canals were filled with fluorescein sodium (Sigma, Alldrich Co., St. Louis, MO, USA) and activated with the relevant activation method for 30 s. Specimens were sectioned horizontally to 1 ± 0.1 mm at 2, 5, and 8 mm from the apex and then examined under the CLSM. Maximum penetration depth, maximum penetration area and penetration percentage were measured by using Image J software. Data were analyzed using a two-way analysis of variance (ANOVA) and posthoc Tukey tests (p = .05). No difference was found between the activation systems in terms of maximum penetration depth and maximum penetration area of irrigation solutions in the apical section (p > .05). The penetration percentage of irrigation solutions was higher in PUI and PIPS compared with EA and XPF at the apical section (p < .05). No difference was found between SNI, PUI, PIPS, and SWEEPS in terms of the penetration percentage of irrigation solutions in all sections (p > .05). The penetration percentage of irrigation solutions was higher in the middle and coronal sections compared to the apical section in EA and XPF (p < .05). Tubule penetration of irrigation solutions in SNI was similar between sections. The Tubule penetration area of irrigation solutions in PUI, EA, XPF, PIPS, and SWEEPS was lower in the apical section than in the middle and coronal sections. RESEARCH HIGHLIGHTS: The tubule penetration depth and area of the irrigation solutions were similar between the activation systems tested in the apical sections. The Tubule penetration area of irrigation solutions in middle and coronal sections was higher in PUI and PIPS than in SNI.

Carbon nanotube-modified adhesive to caries affected dentin conditioned with Nd: YAP laser, phosphoric acid, and photoactivated-erythrosine

AIM

Dentin conditioned with phosphoric acid (PA) Nd: YAP laser, and photoactivated-Ery(Erythrosine) on microleakage, shear bond strength (SBS) degree of conversion (DC), and rheological assessment of adhesive-infused with carbon nanotubes (CNTs).

MATERIAL AND METHOD

Carious ninety-six human mandibular molars were included. Specimens were disinfected and allocated into three groups based on surface pretreatment (n = 32) Group 1 (PA), Group 2 (Nd: YAP) laser, and Group 3 (Photoactivated-Ery). Conditioned groups were further divided into two 2 subgroups based on the application of unmodified ERA and CNTs-modified ERA. Composite restorations were placed on the CAD surface and thermal aging of the samples was performed. The microleakage assessment was conducted using a dye penetration test. Universal testing machine (UTM) assessed SBS bond failure was evaluated using a stereomicroscope. Scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analyses of CNT, and Fourier Transform Infrared FTIR of adhesives were performed. One-way ANOVA and Tukey post hoc analyzed the outcomes.

RESULTS

Group 1B samples (PA+ CNTs modified adhesive) presented the minimum marginal leakage and highest bond integrity. Group 2A (Nd:YAP laser+Unmodified adhesive) displayed the maximum scores of microleakage and lowest bond strength.

CONCLUSION

Photoactivated Ery-PS can serve as an alternative to phosphoric acid for conditioning CAD. Incorporating CNT in adhesive significantly enhanced bond integrity and marginal seal with no significant difference in DC.

The Effectiveness of Three Different Irrigant Activation Methods in the Elimination of Enterococcus faecalis from Root Canals

Background and Objective: Eliminating intracanal Enterococcus faecalis (E. faecalis) is challenging because of its ability to penetrate deep dentinal tubules and its high resistance to many chemicals. This study evaluated the effectiveness of conventional needle irrigation and three different irrigant activation methods in reducing E. faecalis. Methods: The root canals of extracted teeth were shaped, contaminated with E. faecalis, and incubated for three weeks. They were randomly allocated to four experimental groups of 15 teeth each according to the final irrigation method: group 1, conventional needle irrigation; group 2, passive ultrasonic (PU) irrigation; group 3, XP-endo Finisher (XPF); and group 4, laser-activated (LA) irrigation. Bacterial samples were taken and cultured before and after these final irrigation procedures. The colony-forming units were counted, and the bacterial reduction percentages of each group were calculated. The Kruskal-Wallis and Dunnet tests were used for statistical analysis. Results: All irrigant activation methods were significantly more effective than conventional needle irrigation. Although the LA group generated more negative samples than PU, there was no statistically significant difference between the LA and PU groups. LA was significantly more effective than the XPF, whereas PU and XPF were statistically similar. Conclusions: Within the limitations of this study, the final irrigation with LA and PU showed the best reductive effect on E. faecalis colonies. Considering that the LA group had more negative samples, it may be chosen as an alternative to enhance root canal disinfection, especially in difficult cases.

An in-vitro study on effects of laser activation on dye penetration in human root dentin

Objective

To evaluate the penetration of a dye in root dentin after activation with different laser wavelengths.

Materials

Palatal roots of 38 human molars were enlarged and disinfected. Irrigation activation was performed with an Er:YAG laser: @50 mJ, 15 Hz (Er:YAG); a 9.3 µm CO2 laser: @40% power (CO2); diode lasers 455 nm/970 nm: @0.8 W, 15 Hz (D455, D970) and 808/980 nm: @1 W (D808, D980) and compared to positive control: etching with 35% H3PO4 (POS); negative control: water (NEG) and conventional needle irrigation: NaOCl and ethylenediaminetetraacetic acid (EDTA) (CONV). Methylene blue solution was introduced in the canal and laser-activated or left untouched for 100 s before the roots were dried and cut into horizontal slices. Dye penetration was automatically calculated by color recognition of two samples per root third (n = 8 per group in each coronal, middle and apical root thirds). The presence and absence of a smear layer was checked in two additional samples of the negative and positive control under scanning electron microscopy (SEM).

Results

Full-depth infiltration was not achieved in any group. Dye penetration in CONV was significantly less than in Er:YAG, CO2, POS, D455, D970, D808 and similar to NEG and D980 when results of different root thirds were pooled.

Conclusion

Laser activation using certain parameters enhanced dye penetration compared to conventional needle irrigation with NaOCl and EDTA (CONV).

Cleaning and disinfection of the root canal system provided by four active supplementary irrigation methods

This in vitro study evaluated the bacterial reduction provided by the EndoActivator (EA), Easy Clean (EC), passive ultrasonic irrigation (PUI), and XP-Endo Finisher. Eight-four mesial roots of mandibular first molars were instrumented, inoculated with Enterococcus faecalis, and divided into four groups (n. 20). Bacterial reduction in the main canals and dentinal tubules were respectively determined by MTT assays and Live/Dead BackLight technique through confocal laser scanning microscopy (CLSM) at 50, 100, and 150 µm in-depth (n. 10 per group). Statistical analyses were conducted following a significance level of 95% (P < 0.05). A significant statistical difference was just identified between XPF and EC in the main canals. In the dentinal tubules from the main root canals, at 100 and 150 µm in-depths, significant statistical differences were only observed between XPF and EC (P = 0.027) for the former and between XPF and EC (P = 0.011) and XPF and PUI (P = 0.021) for the latter. In the dentinal tubules from the isthmus, at 100 µm in-depth, statistically relevant differences did occur between XPF and EC (P = 0.038) and EC and EA (P = 0.029). At 150 µm in-depth, these differences were only significant by comparing XPF and PUI (P = 0.025) and XPF and EC (P = 0.036). Although no irrigation method could thoroughly disinfect the RCS, bacterial reduction indexes were generally better after using XPF.

Canal disinfection using photo-chemically activated micro-bubble emulsion, Emblica officinalis, and Nd: YAP laser on smear layer and push-out bond strength of resin-based root canal sealer to the radicular dentin

AIMS

Evaluation of the effects of the latest root canal disinfectants i.e., Micro-bubble emulsion (MBE), Neodymium-doped yttrium aluminum perovskite (Nd: YAP), Emblica officinalis (E. officinalis) on the removal of smear layer (SL) and push out bond strength (PBS) of resin-based root canal sealer to the radicular dentin.

METHODS

The coronal portion of sixty single-rooted human mandibular premolar teeth was precisely sectioned at the cementoenamel junction. The canals were prepared to utilize ProTaper universal rotary files till F3. All the study specimens were divided into four groups based on the disinfection regime (n = 15) Group 1: 5.25% NaOCl, Group 2: MBE, Group 3: Nd: YAP laser and Group 4: E. officinalis extract. All the canals were then finally irrigated using 17% EDTA solution as a final disinfecting agent. SL removal assessment was performed on five samples from each group using a scanning electron microscope (SEM). Ten samples from each group were then filled with root canal filling material and the roots were sectioned. Push-out test and failure mode analysis were performed using the universal testing machine (UTM) and stereomicroscope respectively. The mean scores of PBS and SL removal were compared using a one-way analysis of variance (ANOVA) and Post Hoc Tukey's HSD test p = 0.05.

RESULTS

Group-2 (MBE + EDTA) coronal section (1.50 ± 0.23) exhibited the most effective eradication of SL from the canal space. The apical third of Group-1 (NaOCl+EDTA) (2.68 ± 0.82) samples demonstrated the least effective removal of SL from the radicular canal. The maximum score of PBS of AH plus sealer to the canal dentin was exhibited by the coronal section of Group-2 (MBE + EDTA) (9.55 ± 0.45 MPa) samples. However, the apical third of Group-1 (NaOCl+ EDTA) specimens (5.16 ± 0.32 MPa) demonstrated the minimum EBS.

CONCLUSION

MBE+ EDTA displayed better smear layer removal and bond integrity of AH plus sealer to the root canal dentin. Nd: YAP+ EDTA laser and E.officinalis displayed comparable outcomes to that of control NaOCl+ EDTA.

Effect of different final irrigation agitation techniques on root canal dentin tubule penetration of nanoparticle calcium hydroxide dressing

This study is aimed to assess the efficacy of different final irrigation agitation techniques on dentin tubule penetration of nanoparticle calcium hydroxide (NCH) dressing. Ninety-six extracted upper incisors were shaped up to #40file. Then, Four experimental groups were formed according to the final irrigation procedure: conventional needle irrigation (CNI), manual dynamic agitation (MDA), sonic agitation (SA) and ultrasonic irrigant agitation (UIA). According to the intracanal drug used, these groups were divided into two subgroups: calcium hydroxide (CH) and NCH. Prepared CH preparations were labelled with Rhodamine B, and CH or NCH were placed in root canals. In the UIA group, both CH and NCH had the highest penetration depth and percentage compared to the other groups (p < 0.05). The penetration depth and percentage of NCH in the UIA and SA groups were significantly higher than in the CH groups (p < 0.05). UIA is more effective than other groups in increasing dentinal tubule penetration of CH and NCH.

The effect of an additional application of sealer prior to backfilling in the Continuous Wave of Condensation technique

An additional sealer application was investigated prior to backfilling with the Continuous Wave of Condensation (CWC). 105 Palatal roots were sectioned and prepared to a file size 40, 0.06 taper with Vortex Blue® files. Groups A, B and C had a single sealer application before while groups D, E and F, received a second application of dyed sealer prior to backfilling. Roots were sectioned at 2,3,4,6,7 and 8 mm from the root apex. The percentage of sealer and dentinal tubular penetration depth was calculated at each level. At each ascending level, the sealer percentage decreased for each experimental group while the number of outer third penetration depths increased when all groups were combined. An additional sealer application prior to backfilling had minimal effect on the percentage of sealer or outer third penetration depths and can be considered a clinical preference rather than an imperative step with the CWC technique.

Current Applications and Future Directions of Lasers in Endodontics: A Narrative Review

The utilization of lasers has been regarded as a novel technique for the purposes of clinical use in the dental field. Recently, numerous studies have been conducted on the potential applications of laser therapy in endodontics. Moreover, due to their ablation, penetrability, and disinfection capabilities, lasers have performed well with respect to endodontic treatments, including root canal treatment, vital pulp therapy (pulp capping and pulpotomy), dentinal hypersensitivity treatment, and management of dental pain related to pulp and periradicular disease. In particular, the superiorities of laser-aided pulp therapy are emphasized through condensed clinical controlled trials, and histological studies, in this review. Moreover, the ingenious use of laser applications with respect to aiding in the acceleration of root development and the extraction of foreign matters (i.e., broken files and fiber posts) in canals has quickly become the cutting-edge trend of current research. This review offers a summary and discussion of the current literature on all the aforementioned laser applications. Moreover, the characteristics of laser devices, including erbium lasers, neodymium-doped lasers, CO2 lasers, and diode lasers, are detailed and discussed here, providing useful references for laser application in endodontics. We also focus on the different wavelengths with respect to the lasers that are applied in endodontics. High-power lasers perform well as operative instruments; in addition, low-level lasers lead to the regulation of pulp inflammation, and the promotion of pulp healing. This narrative review provides a summary of the advanced applications of lasers in conjunction with various devices in the practice of endodontics, and aims to inspire innovative perspectives on lasers in the context of the treatment of dental diseases, especially pulp diseases, in the future.

Dentinal tubule penetration of sodium hypochlorite in root canals with and without mechanical preparation and different irrigant activation methods

Objectives

This study evaluated the dentinal penetration depth of 2.5% sodium hypochlorite (NaOCl) in root canals with and without preparation and different irrigant activation protocols.

Materials and Methods

Sixty-three bovine mandibular incisors were randomly allocated to 6 groups (n = 10): G1, preparation + conventional needle irrigation (CNI); G2, preparation + passive ultrasonic irrigation (PUI); G3, preparation + Odous Clean (OC); G4, no preparation + CNI; G5, no preparation + PUI; G6, no preparation + OC; and CG (negative control; n = 3). Samples were filled with crystal violet for 72 hours. Irrigant activation was performed. Samples were sectioned perpendicularly along the long axis, 3 mm and 7 mm from the apex. Images of the root thirds of each block were captured with a stereomicroscope and analyzed with an image analysis software. One-way analysis of variance, followed by the Tukey post hoc test, and the Student's t-test were used for data analysis, with a significance level of 5%.

Results

The NaOCl penetration depth was similar when preparation was performed, regardless of the method of irrigation activation (p > 0.05). In the groups without preparation, G6 showed greater NaOCl penetration depth (p < 0.05). The groups without preparation had a greater NaOCl penetration depth than those with preparation (p = 0.0019).

Conclusions

The NaOCl penetration depth was similar in groups with root canal preparation. Without root canal preparation, OC allowed deeper NaOCl penetration. The groups without preparation had greater NaOCl penetration than those undergoing root canal preparation.

Advances in the Role of Sodium Hypochlorite Irrigant in Chemical Preparation of Root Canal Treatment

Irrigation of root canal system is of great significance to the success of endodontic treatment, where sodium hypochlorite (NaOCl) is the most widely used irrigant in chemical preparation. NaOCl functions by eliminating bacterial biofilms and dissolving organic tissue, which may vary according to several factors such as the microbiology of root canal infection and the concentration of the irrigant. It has been proposed that the effectiveness of NaOCl could be enhanced via several methods, including heating the irrigant, applying in conjunction with certain reagents, or activating by agitation techniques. Despite its antibacterial and tissue-dissolving capacities, NaOCl should be used with caution to avoid detrimental effect due to its cytotoxicity and negative effect on dentin properties. In this narrative review, we discussed the factors that affect the properties of NaOCl, the methods to improve its efficacy, and the side effects that might occur in clinical practice.

Evaluation of dentinal tubule penetration of Irritrol and chlorhexidine irrigating solutions activated using EDDY and photon-initiated photoacoustic streaming

The aim of the study was to compare the penetration depth and percentage of Irritrol and chlorhexidine (CHX) solutions into dentinal tubules using conventional needle irrigation (CI), EDDY, and photon-induced photoacoustic streaming (PIPS). Sixty oval shaped mandibular premolar teeth were divided into two main groups according to the irrigating solutions as follows; Irritrol and CHX, which were later randomly divided into three subgroups according to the activation technique; CI, EDDY and PIPS (n = 10). Following the irrigation activation procedures, all roots were horizontally sectioned at 3 (apical), 8 (middle), and 13 (coronal) mm from the root apex and then examined with confocal laser scanning microscope (CLSM). Penetration depth (µm) and penetration percentage (%) as determined from the images were analyzed using LSM Image Browser software (Zeiss) and Image J analysis software (V. 1.44p; National Institutes of Health, Bethesda, MD), respectively. Data were statistically analyzed using Kruskal-Wallis and Mann-Whitney U tests were performed for multiple comparisons. In both Irritrol and CHX groups, the PIPS activation system demonstrated the highest values for irrigant penetration depth and penetration percentage compared with the other activation methods. Activation of the CHX and Irritrol the final irrigating solutions with PIPS activation technique improved the penetration depth and percentage solutions into the dentinal tubules.

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.

Evaluation of the effect of calcium hydroxide paste on sealer penetration into dentinal tubules by confocal laser scanning microscopy

The study evaluated sealer penetration after calcium hydroxide (Ca(OH)₂ ) removal from the root canals. Sixty single-rooted mandibular premolars were divided into six groups. Ca(OH)₂ paste placed into the root canals except for the control group (CG) was removed using the following irrigation techniques: conventional needle irrigation (CNI), EndoActivator (EA), EndoVac (EV), passive ultrasonic irrigation (PUI) and photon-induced photoacoustic streaming (PIPS) technique. After canal filling, the penetration depth, penetration area and penetration percentage of the sealer were determined using confocal microscopy. The CG and EA had a greater penetration depth than CNI in the middle section. The CG exhibited a higher dentinal tubule penetration area than CNI, EV and PUI in the middle section. EA was significantly more effective than PUI in the coronal section for the percentage of sealer penetration. EA and PIPS removed Ca(OH)₂ from root canals effectively because they presented similar penetration to the CG in all sections.

Effect of Various Laser-Activated Irrigation Protocols on Endodontic Sealer Penetration into the Dentinal Tubules: A Confocal Laser Scanning Microscopy Study

Objective: To study the effect of various laser-activated irrigation protocols on endodontic sealer penetration into the dentinal tubules. Background data: Laser-activated irrigation is helpful for smear layer removal and thus might increase the penetration of endodontic sealer into the dentinal tubules. Methods: Forty-eight mandibular premolars with straight canals were instrumented and divided into four groups: C-I group, conventional needle irrigation with sodium hypochlorite (NaOCl) followed by ethylenediaminetetraacetic acid (EDTA); Er:YAG-I, Er,Cr:YSGG-I, and Nd:YAP-I groups, NaOCl and EDTA irrigations activated by erbium:yttrium-aluminum-garnet (Er:YAG), erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG), and neodymium:yttrium-aluminum-perovskite (Nd:YAP) lasers, respectively. The cleanness of the treated canals was evaluated by scanning electron microscopy (SEM). Then, canals were obturated with AH-Plus sealer labeled with rhodamine B (0.1%) and combined with gutta-percha. After setting, canals were sectioned at 2, 5, and 8 mm short from the root apex, and the penetration area of the AH-Plus into the dentinal tubules was observed using confocal laser scanning microscopy (CLSM). Results: SEM results indicated that the Er:YAG-I and Er,Cr:YSGG-I lasers were more effective than the Nd:YAP-I and C-I in removing the smear layer. CLSM results indicated that the average AH-Plus penetration areas among the tested groups were in ascending order: C-I < Nd:YAP-I < Er:YAG-I, Er,Cr:YSGG-I (p < 0.05). Conclusions: Laser-activated irrigations significantly increased the penetration of the endodontic sealer into the dentinal tubules, among which Er:YAG-I and Er,Cr:YSGG-I lasers were the most effective and may be considered routine protocols for endodontic treatment.

Efficiency and Temperature Rise of File Ablation by Neodymium:Yttrium-Aluminum-Perovskite Laser In Vitro

INTRODUCTION

Retrieving a separated file in the root canal system requires a skilled clinician. A metal file can be removed by ablation via the neodymium:yttrium-aluminum-perovskite (Nd:YAP) laser; however, the efficiency and potential hazards of the ablation procedure are still unclear. The aim of this study was 2-fold: to investigate the efficiency of file ablation using the Nd:YAP laser and to evaluate the rise in temperature of the root surface in vitro.

METHODS

In part 1 of this study, #10 and #15 C-files (VDW GmbH, Munich, Germany) and ProTaper Next X1 and X2 files (Dentsply Maillefer, Ballaigues, Switzerland) were selected. Under 8.5×, the Nd:YAP laser was used to ablate the files starting at the tip of the file. The length of the file was recorded after each 5-pulse ablation. In part 2 of this study, 3 files each of the #15 C-file and the ProTaper Next X2 were separated in 6 distal roots of mandibular second molars with single canals. Two-pulse and 5-pulse modes were used to ablate the separated files, and the rise in root surface temperature was recorded with an infrared camera. Another 3 unaltered distal roots served as the negative control. For scanning electron microscopic evaluation, the teeth were split with bone scissors and observed under a scanning electron microscope to evaluate the surface change of the file and the root canal wall.

RESULTS

The average length of the ablated files after each 5-pulse interval was 0.113-0.158 mm with no statistical difference between the different files.The temperature rise of the negative control group (mean ± standard deviation = 1.86° ± 0.11°C and 5.81° ± 0.35°C for the 2- and 5-pulse group) was significantly lower than the roots with separated files (mean ± standard deviation = 3.74° ± 0.20°C and 4.02° ± 0.11°C for 2-pulse C-file and ProTaper Next X2; 8.47° ± 0.19°C and 9.04° ± 0.20°C for 5-pulse C-file and ProTaper Next X2). The temperature rise of all groups was lower than 10°C. The 2-pulse group showed a lower temperature rise than the 5-pulse group. The diameter or the type of alloy had no effect on the temperature rise.

CONCLUSIONS

Separated files (stainless steel or nickel-titanium alloy) can be ablated by the Nd:YAP laser. When the number of pulses is less than 5, the temperature rise of the root surface is considered safe to the surrounding periodontium.

Evaluation of the penetration of CHX 2% on dentinal tubules using Conventional Irrigation, Sonic Irrigation (EDDY) and Passive Ultrasonic Irrigation (PUI) techniques: An in vitro study

Background

Various procedures and techniques have been developed to increase the effectiveness and penetration of irrigants into the dentinal tubules and anatomical anfractuosities. Objective: The purpose of this in vitro study was to compare the effect of different irrigation techniques such as conventional irrigation with a syringe, sonic activation irrigation with EDDY and Passive Ultrasonic Irrigation. All these on dentinal tubule penetration using Chlorhexidine.

Material and Methods

45 lower premolar teeth extracted for orthodontic reasons were used. These teeth were decoronated to a length of 18mm. This working length was achieved by inserting a size 15 K file into the root canal until it was observed in the ápex. Then the length was reduced to 1 mm. The instrumentation was performed with the Wave One Gold system up to a file # 45. Irrigated with 2mL of CHX between instruments. A final irrigation was performed using 5 mL of 17% EDTA with an E1 - Irrisonic insert for 30 seconds. Then, the root canal was irrigated with 5 mL of distilled water and dried with paper tips. The final irrigation of the 2% CHX with Rhodamine B was carried out with the different techniques of irrigation. Syringe irrigation with 5 mL, sonic irrigation and passive ultrasonic activation activated for 30 seconds in two stages. Axial cuts were made at 200 microns, the observation was done with stereomicroscope and image analysis in Image J software.

Results

Statistically significant differences were found only in the apical region, where the depth penetration in the PUI group was 76 µm, MI 48 µm and SI 41 µm, while in the penetration area, the PUI group was 99 µm2, MI 77 µm2 and finally SI 53 µm2.

Conclusions

The CHX was able to penetrate the dentinal tubules of three-thirds of the roots, for which the technique that showed the greatest penetration capacity was the ultrasonic activation.

Key words:Clorhexidine. Dentinal tubule. Dentinal penetration. Passive ultrasonic irrigation. Eddy. Manual irrigation.

Effect of different irrigation methods in the presence of a separated instrument: an in vitro study

Objective: The aim of this study was to evaluate the effect of different irrigation methods on sodium hypochlorite (NaOCl)/debris extrusion and dentinal tubule penetration of 2.5% NaOCl in the presence of an apically separated instrument.Materials and methods: Sixty root canals of freshly extracted mandibular single-rooted premolars were chemomechanically prepared up to ProTaper F2. Manual needle irrigation (30-gauge/side-vented) with 2.5% NaOCl was performed between files and a smear layer was removed with 17% ethylenediaminetetraacetic acid. Three mm of notched ProTaper F3 files were separated in the apical third of the roots. Samples were then randomly divided according to the final irrigation systems as follows: EndoActivator, EndoVac, manual needle irrigation, passive ultrasonic activation, and RinsEndo. Samples were mounted to Eppendorf tubes and root canals were irrigated with 3-mL Rhodamine B-labelled 2.5% NaOCl, which was applied using one of the above-mentioned methods. The extruded NaOCl/debris weight was calculated by extracting pre-irrigation weights of tubes from post-irrigation ones. Samples embedded in acrylic resin were sectioned transversely in 1-mm thicknesses at apical 1- and 3-mm levels. NaOCl's penetration depth and percentage into the dentinal tubules were evaluated with the aid of a confocal laser scanning microscope. Data were analysed statistically with Kruskal-Wallis and post hoc Siegel-Castellan tests (p < .05).Results: EndoVac significantly decreased the extruded NaOCl/debris compared to RinsEndo, passive ultrasonic activation, and EndoActivator in the presence of a separated instrument (p < .05). The penetrability of NaOCl significantly increased with the use of RinsEndo and EndoVac compared to the remaining groups (p < .05).Conclusion: In the presence of an irretrievable separated instrument, it could be suggested that devices with apical negative pressure such as EndoVac may improve the penetrability of irrigation solutions to the apical part of the root while preserving periapical tissues from NaOCl/debris extrusion.

Sealer penetration: effect of separated file's cross-section, taper and motion characteristics

OBJECTIVES

The separated root canal instruments may affect the quality of root canal filling, hence the success of endodontic treatment. The aim of this study was to evaluate the effects of separated file fragments of nickel-titanium rotary systems with different cross-section, taper and motion characteristics on the apical sealer penetration in oval-shaped root canals via confocal laser scanning microscope (CLSM).

MATERIALS AND METHODS

Distal roots of 60 mandibular molars with oval-shaped root canals were randomly divided into 4 groups as follows: group 1, FlexMaster Nickel Titanium Rotary File System (NTRFS) (separated instrument: 30/.06); group 2, ProTaper Next NTRFS (X3); group 3, ProTaper Universal NTRFS (F3); group 4, Revo-S NTRFS (AS30/.06). Root canals were filled with gutta-percha and AH plus labelled with 0.1% rhodamine B using a warm vertical compaction technique. Each specimen was horizontally sectioned at 1st, 3rd and 5th mm from apical foramen. Amount of maximum and average penetration depths, penetration percentage and sealer penetrated area were measured and analysed with one-way repeated measures of ANOVA and the Bonferroni post hoc tests. p < 0.05 was considered significant.

RESULTS

The penetration depth, percentage and penetrated area of the sealer increased from apical to coronal in all systems. The maximum and average penetration depths and penetration areas were higher in FlexMaster and Revo-S groups at the 3rd mm (p < 0.05). At the 5th mm, the Revo-S group had a higher penetration percentage, when compared with ProTaper Next and ProTaper Universal groups (p < 0.05).

CONCLUSIONS

In the 1st mm, separated fragments of any system did not allow the penetration of the sealer, while it was observed that the files with constant taper showed more positive results in terms of sealer penetration at apical 3rd and 5th mm.

CLINICAL RELEVANCE

In the presence of a separated file, the taper of the file might significantly affect the amount of penetrated sealer into the dentinal tubules as compared with the cross-section and motion characteristics of the file.

Efficacy of the Rotary Instrument XP-Endo Finisher in the Removal of Calcium Hydroxide Intracanal Medicament in Combination with Different Irrigation Techniques: A Microtomographic Study

OBJECTIVES

This study aims to evaluate the efficacy of the rotary instrument XP-endo Finisher for the removal of Ca(OH)₂ aided by different irrigation regimens.

METHODS

Sixteen double-rooted upper premolar human teeth were selected for the study. Thirty-two canals were prepared using a ProTaper Next rotary system up to X3. Then, the canals were filled with Ca(OH)₂. The volume of Ca(OH)₂ inside the canals was measured by microcomputed tomography (micro-CT). After that, the teeth were randomly allocated into two experimental groups, i.e., A and B (n = 16 canals). In group A, Ca(OH)₂ was removed using the master apical file (X3). In group B, Ca(OH)₂ was removed using a XP-endo finisher. In half of both groups (n = 8), syringe irrigation (SI) was used, while passive ultrasonic irrigation (PUI) was used for the other half. After removal, the remaining volume of Ca(OH)₂ was measured. All data were statistically analyzed using two-way ANOVA with Tukey's post hoc test.

RESULTS

The percentages of remaining Ca(OH)₂ in the apical thirds of all canals were significantly higher as compared with the middle and coronal thirds in all groups (p < 0.05). There was no significant difference between different files and techniques (p > 0.05).

CLINICAL SIGNIFICANCE

This study presents a new method for the removal of Ca(OH)₂ from root canals.

Effectiveness of Various Final Irrigation Techniques on Sealer Penetration in Curved Roots: A Confocal Laser Scanning Microscopy Study

Objective

To compare the efficacy of various techniques used for final irrigation on sealer penetration in the apical one-third of curved root canals. Material and Methods. Sixty-five freshly extracted maxillary first molar teeth with mesiobuccal roots having more than 20° of root curvature were used. The root canals were instrumented and randomly divided into four experimental groups and one control group. In the 4 experimental groups, 3 ml of 17% EDTA followed by 3 ml of 5.25% NaOCl was delivered with the use of the following protocols: Group 1: manual dynamic activation (MDA), Group 2: sonic irrigation (SI), Group 3: passive ultrasonic irrigation (PUI), and Group 4: conventional needle irrigation (CI). All teeth were obturated with gutta-percha and AH Plus sealer labeled with fluorescent dye. Transverse sections at 2 mm and 4 mm distance from the root apex were examined with the aid of confocal laser scanning microscopy. Total percentage (%) and maximum depth (μm) of sealer penetration were measured.

Results

All the experimental groups exhibited significantly higher penetration rates than the control group at both sections (p < 0.05). However, no significant differences were found in the penetration depth and percentage among the four experimental groups evaluated at both sections (p > 0.05).

Conclusion

PUI, SI, and MDA did not significantly improve sealer penetration in the apical portion of curved root canals when compared to conventional needle irrigation.

Comparative Evaluation of Depth of Penetration of Root Canal Irrigant After Using Manual, Passive Ultrasonic, and Diode Laser-Assisted Irrigant Activation Technique

AIM:

The aim of this study was to compare and evaluate the penetration depth of irrigant after using manual, passive ultrasonic, and diode laser–assisted irrigant activation technique.

Materials and Methods:

Ninety extracted single-rooted human mandibular premolars were selected (N = 90). Teeth were decoronated and working length was standardized for 12 mm. Root canals were shaped using ProTaper Universal F3. Saline was used as an irrigant in between every successful instrumentation. After completion of chemomechanical preparation, root canals were filled with Rhodamine-B-labeled sodium hypochlorite (3%). Teeth samples were divided into three experimental groups. In Group 1 (n = 30), manual irrigant activation was performed for 30 seconds with master cone gutta-percha (F3) in gentle up and down motion. In Group 2 (n = 30), ultrasonic irrigant activation was performed using passive ultrasonic endo tips for 30 seconds. In Group 3 (n = 30), laser activation was performed using diode laser for 30 seconds with 200-µm tips. Transverse sections were made at 2, 5, and 8 mm from the root apex and were observed under confocal laser scanning microscopy. Maximum penetration depth of irrigant was recorded and statistically analyzed.

Result:

In the all three groups, coronal third (sections at 8 mm from root apex) showed the highest penetration depth of irrigant. Laser activation (Group 3) showed the highest penetration depth in all the three sections when compared with manual and passive ultrasonic irrigant activation. One-way analysis of variance and post hoc test showed there were significantly high differences among all the three groups and also at all three levels (P < 0.05).

Conclusion:

Diode laser–assisted irrigant activation technique had better penetration depth in all the three aspects of root dentin.

Penetration of sodium hypochlorite into root canal dentine: effect of surfactants, gel form and passive ultrasonic irrigation

AIM

To assess the penetration of sodium hypochlorite (NaOCl) gel or NaOCl solutions with surfactants, and the effect of passive ultrasonic irrigation (PUI) on penetration into dentinal tubules.

METHODOLOGY

Bovine incisor root canals were instrumented, the roots sectioned and the dentine blocks obtained were stained with crystal violet. Dentine blocks (n = 10 per group) were exposed to 3% NaOCl gel or 3% NaOCl solution for 10 and 20 min. Other dentine blocks (n = 10 per group) were exposed to Chlor-Extra (6% NaOCl + surfactant), 6% NaOCl, 2.5% NaOCl with 0.2% cetrimide and 2.5% NaOCl for 10 and 20 min. The penetration depth of irrigants into dentinal tubules was measured in micrometres by viewing the bleached crystal violet under a stereomicroscope. Additionally, bovine incisor root canals, instrumented and stained with crystal violet, were distributed into two groups (n = 10) and irrigated with 2.5% NaOCl with PUI or conventional syringe irrigation (CSI). The penetration depth of irrigants into dentinal tubules was assessed 3 and 7 mm from the apex. Statistical analysis was performed by ANOVA and Tukey tests (α = 0.05).

RESULTS

There was significantly greater penetration of 3% NaOCl solution into dentinal tubules compared with the gel form (P < 0.05). There was no difference (P > 0.05) between 6% NaOCl and Chlor-Extra, and between 2.5% NaOCl and 2.5% NaOCl + cetrimide. PUI significantly increased the penetration depth of NaOCl into dentinal tubules when compared with CSI (P < 0.05).

CONCLUSIONS

In extracted bovine incisors, NaOCl gel penetrated less into dentinal tubules than NaOCl solution. The addition of surfactants did not increase the penetration depth. The use of PUI significantly increased NaOCl penetration into dentinal tubules.

Influence of the EndoActivator Irrigation System on Dentinal Tubule Penetration of a Novel Tricalcium Silicate-Based Sealer

This study compared the effects of a conventional endodontic needle with an agitation system on a novel tricalcium silicate-based sealer (NTS) in terms of dentinal tubule penetration and interfacial adaptation to a root canal. Fifty single-rooted, recently-extracted human maxillary central incisors were randomly distributed into two homogeneous groups characterized by two different final cleansing systems: Conventional endodontic needle, or EndoActivator^®. After instrumentation, all the teeth were filled with the gutta-percha single cone technique in conjunction with the novel tricalcium silicate-based sealer. Teeth were horizontally sectioned at 1 and 5 mm from the apex and were observed under a confocal laser scanning microscope (CLSM) at five magnifications. The maximum, mean, and the circumferential percentage of the sealer penetration inside the tubules were measured. Moreover, the gap width was evaluated using Image J software (National Institutes of Health, Bethesda, MD). EndoActivator^® did not result in a significantly higher circumferential percentage of sealer penetration than conventional irrigation (p > 0.05). However, the gap width was significantly lower with EndoActivator^®, compared to conventional needles at both 1 mm (p = 0.035) and 5 mm (p = 0.038). The EndoActivator^® irrigation system did not significantly improve the NTS penetration, as compared to the conventional endodontic needle irrigation. Activation of the irrigation reduced the gap width significantly.

Influence of size and insertion depth of irrigation needle on debris extrusion and sealer penetration

Objectives

To determine the effect of size and insertion depth of irrigation needle on the amount of apical extruded debris and the amount of penetration depth of sealer using a confocal laser scanning microscope (CLSM).

Materials and Methods

Twenty maxillary premolars were assigned to 2 groups (n = 10), according to the size of needle tip, 28 G or 30 G. Buccal roots of samples were irrigated with respective needle type inserted 1 mm short of the working length (WL), while palatal roots were irrigated with respective needle type inserted 3 mm short of the WL. Prepared teeth were removed from the pre-weighed Eppendorf tubes. Canals were filled with F3 gutta-percha cone and rhodamine B dye-labeled AH 26 sealer. Teeth were transversally sectioned at 1 and 3 mm levels from the apex and observed under a CLSM. Eppendorf tubes were incubated to evaporate the irrigant and were weighed again. The difference between pre- and post-weights was calculated, and statistical evaluation was performed.

Results

Inserting needles closer to the apex and using needles with wider diameters were associated with significantly more debris extrusion (p < 0.05). The position of needles and level of sections had statistically significant effects on sealer penetration depth (p < 0.05 for both).

Conclusions

Following preparation, inserting narrower needles compatible with the final apical diameter of the prepared root canal at 3 mm short of WL during final irrigation might prevent debris extrusion and improve sealer penetration in the apical third.