Background: Pulp tissue debridement and the eradication of microorganisms from an infected root canal system before obturation is a primary focus of endodontic treatment and the best predictor for the long-term success of endodontic treatment. Objective: The purpose of this in vitro laboratory study was to evaluate pulp tissue debridement and the disinfection efficacy of two different Er;Cr:YSGG laser units, with a 2790 nm wavelength, compared to ultrasonic-activated irrigation (UAI) in root canals infected with Enterococcus faecalis. Methods: Human non-infected mandibular first molars were extracted, disinfected, and cultured with Enterococcus faecalis. Different types of Er;Cr:YSGG laser irrigation and UAI were performed according to the manufacturers’ protocols. The teeth were then processed for bacteriological and SEM analyses. Results: The different laser-activated irrigation protocols showed multiple areas of remaining bacteria, biofilm, tissue, and thermal ablation. The laser fiber tips also displayed significant tip degradation after use, which might affect efficacy. Conclusions: In this in vitro study, laser-activated irrigation using Er;Cr:YSGG technology and UAI were inefficient in eliminating pulp tissue from difficult-to-reach areas and Enterococcus faecalis from infected root canals.

Objective: To investigate the tissue dissolution efficacy of different concentrations of sodium hypochlorite (NaOCl) using the GentleWave® technology (GW) and compare it with that of passive ultrasonic irrigation. This study will provide a novel in vitro model used to evaluate the tissue dissolution efficacy of different concentrations of NaOCl using the GentleWave® procedure. Materials and Methods: Palatal bovine tissue was standardized by weight at 70–75 mg (average of 74.4 mg). The samples were divided into three groups of n = 10, Group 1: GW + 0.5% NaOCl, Group 2: GW + 3% NaOCl, and Group 3: ultrasonic group (US) + 6% NaOCl, and a control group of n = 2 with GW + H2O. A specialized CleanFlow instrument was manufactured for the GW groups. For the US group, an apparatus was developed to allow the tissue to be in close contact with a freely operating ultrasonic tip. Each group was operated with its specific irrigants and dissolution times were obtained unless the samples were not visually dissolved within 5 min, and the dissolution rates were calculated. Dissolution times and rates were analyzed using univariate analysis of variance followed by a t-test. Results: The GW groups with 0.5% and 3% NaOCl dissolved entire tissue samples within 5 min and had average dissolution times of 227.5 s (Group 1) and 81.5 s (Group 2). GW with water had a higher tissue dissolution rate than ultrasonics with 6% NaOCl. Conclusions: The GentleWave® using a lower concentration of NaOCl showed a similar clinical efficacy of dissolving tissues but displayed a significantly faster rate when compared with passive ultrasonic agitation.

Recently, the single-cone hydraulic canal filling technique using bioceramic sealers was found to hinder retreatment due to the mechanical properties of the bioceramic sealers. This study assessed the effectiveness of four nickel–titanium rotary files in removing gutta-percha and bioceramic sealer from molar root canals in vitro. Eighty-eight root canals from extracted molars were instrumented with Vortex Blue rotary files and filled with gutta-percha and bioceramic sealer using a single-cone technique. After 30 days, the filled canals were randomly divided into four groups according to the file used for re-instrumentation: ProTaper Gold (PTG), Endo ReStart (ERS), XP-3D Shaper (XPD), and HyFlex Remover (HFR). This study assessed whether root canal filling material removal and patency were achieved within a 10-min time frame, recording the time required in seconds. The rate of regaining patency and the time required to achieve patency were compared among groups using a generalized linear model. Scanning electron microscopy was used to evaluate the mechanical changes to the files after use. The patency rate of XPD and HFR was significantly higher than PTG. ERS and XPD demonstrated shorter patency times than HFR and significantly shorter patency times than PTG. SEM images revealed a varied range of reverse windings across file groups. PTG and ERS exhibited microcracks and fractured tips, while XPD and HFR did not display these mechanical alterations. The four file systems in this study displayed varying levels of effectiveness in the retreatment of root canals filled with bioceramic sealers.

Objective The aim of this study was to evaluate six files on the pericervical dentin (PCD) and the smallest dentin thickness zones (SDTZ) in mesial root canals of mandibular molars. Materials and methods Sixty mandibular molars with two mesial canals and Vertucci configuration were aleatory allocated in 6 experimental groups of 10 molars and 20 root canals. Specimens were scanned before instrumentation using the SkyScan 1275 (Bruker microCT, Kontich, Belgium). Group 1 was treated with WaveOne Gold (WG), group 2 with Reciproc Blue (RB), group 3 with TRUShape (TS), group 4 with XP-endo Shaper (XP), group 5 with iRace (IR), and group 6 with TruNatomy (TN). After instrumentation, the molars were scanned again and the images recorded were reconstructed with the NRecon v.1.7 (Bruker micro-CT) and analyzed with CTAn v.1.20.8 software (Bruker micro-CT) quantifying the changes produced in the surface, volume, structure thickness, SMI, and centroids at the Pericervical Dentin area of the root canals (PCD) located from the root canal orifices at the floor of the pulp chamber to 4 mm in the apical direction, and the changes in the Smallest Dentin Thickness Zones (SDTZ) located (from the furcation to 4 mm and 7 mm in the apical direction. The data obtained were compared using Wilcoxon and ANOVA with a 5% significance level. Results XP and TN were similar in all the parameters ( P >.05) at the PCD, but TN showed significant differences from WG, RB, TS, and IR ( P <.05), while XP showed significant differences from WG ( P <.05) in volume, surface, and structure thickness. Regarding the changes in the SDTZ, the amount of dentin removed was similar between the groups in both canals at the middle 1/3, at the cervical 1/3 for MB canals, and in ML canals for RB, TS, XP, IR, and TN ( P >.05). The action of WG was significantly different from that of XP and TN in the cervical 1/3 of the ML canal ( P <.05). Conclusions XP and TN rotatory files with small taper and volume maintained better with minor changes at the PCD and SDTZ, while WG reciprocation file produced the largest change. All the files were maintained centered at the PCD, and their performances were safe with a minimal thickness higher 0.5 mm at the SDTZ, and without risk of perforation. Trial registration No clinical trials were indicated in this study. Clinical relevance The choice of endodontic files is a relevant factor in the conservative performance of root canal treatments.

Currently, premixed putty-type bioceramic cements (PPBCs) have become popular materials for root-end fillings. This study investigated three root-end filling techniques using PPBCs and calcium silicate-based sealers including EDTA pretreatment. Ninety root segments were prepared and standardized with an artificial fin and lateral canal, and assigned to three groups (n = 30). Root-end fillings were placed using BC-RRM Putty alone (Group PA), injection of BC sealer followed by BC-RRM Putty (Lid Technique: Group LT) or BC-RRM Putty with BC sealer coating (Deep putty packing technique: Group DP). Half of each group was pretreated with 17

The goal of root canal treatment is to prevent and treat apical periodontitis, by eliminating inflamed pulp tissue as well as microorganism and necrotic pulp tissue by chemomechanical debridement and providing a good quality root canal filling. According to Sjögren, et al. [1] the success rate of root canal treatment goes as high as 96% in teeth without periapical lesions. Salehrabi, Rotstein [2] metanalyses, found a 97% retention rate of root canal treated teeth while Hannahan, Eleazer [3] showed no statistical difference in the success rate between single implants and teeth with non-surgical root canal treatments. The root canal instrumentation is perform using different type of hand files or mechanical driven rotary or reciprocation instruments. However, during root canal instrumentation dentin debris, pulp tissue, and bacteria are likely to get extruded through the apical foramen. This extrusion might be responsible for the presence of severe postoperative pain and/or swelling [4].

The successful treatment of the root canal requires the elimination of pulp tissue and bacteria and the alteration of its environment to prevent further colonization. The root canal irrigation is the introduction of chemicals for antimicrobial activity, demineralization, tissue dissolution, bleaching, deodorizing, and hemorrhage control through a flushing mechanism. Several irrigating solutions have cytotoxic potential, and they may cause damage if they gain access into the periapical tissues, high concentration can also cause erosion on the canal dentinal walls. The disinfection of the root canal system is challenging due to the complex internal anatomy and dentin composition, mechanical preparation cannot achieve the complete removal of pulp tissue and bacteria, and current irrigants cannot accomplish all the tasks required; a detailed understanding of the mode of action of various solutions is essential for optimal irrigation. We will discuss new developments on broad antimicrobial agents against bacteria and fungi typical of the root canal infection without cytotoxicity and mechanical devices for safe and adequate irrigation.

Background: This study evaluated the efficacy of a multisonic technology for the debridement of vital and necrotic pulp tissues in freshly extracted human mandibular molar teeth. Methods: Twelve teeth with a diagnosis of symptomatic irreversible pulpitis (SIP) and twelve teeth with a diagnosis of pulp necrosis with symptomatic apical periodontitis (SAP) were extracted. The GentleWave® procedure was performed on 10 teeth from each group. Four non-treated teeth served as histologic controls. Histological consecutive 5 µm sections were obtained from the apical, middle, and coronal portion of the canals. The canals were evaluated for the presence of pulpal debris and bacteria. Results: In nine out of the ten specimens with SIP, no pulpal debris was detected in any portion of the canals. In the necrotic pulp group, eight out of the ten specimens had no detectable pulpal debris in any portion of the canal spaces. No bacteria were detected in the main canals, isthmuses, or lateral canals, but were detected deep within the dentinal tubules in 10 specimens. Conclusions: This study demonstrated that the multisonic technology was effective at removing vital and necrotic pulp tissue as well as bacteria from the root canal system, including inaccessible areas.

The aim was to assess the effect of XP-endo Finisher (XPF) on multispecies biofilm removal, in comparison with passive ultrasonic irrigation (PUI) and conventional syringe irrigation (CSI), by scanning electron microscope (SEM). Fifty mandibular first premolars were instrumented, longitudinally sectioned. The split halves were incubated for 4 days with a broth obtained from three bacteria strains: Enterococcus faecalis, Eikenella corrodens and Streptococcus anginosus. Subsequently, the re-approximated split halves were irrigated with 4% sodium hypochlorite (NaOCl) or water using CSI, and the final irrigation protocols were CSI with 4% NaOCl (CSI+4%NaOCl), PUI+4%NaOCl, XPF+4%NaOCl and CSI+water. The analysis of biofilm removal was performed using SEM images. There were no differences between PUI and XPF (P > 0.05), and both groups promoted higher biofilm removal than CSI+4%NaOCl and CSI+water groups (P < 0.05). It can be concluded the multispecies biofilm removal was significantly improved using XPF and PUI when compared to CSI.

Introduction: This research studies and compares the shaping ability of WaveOne Gold (WG; Dentsply Tulsa Dental Specialties, Tulsa, OK), the Reciproc Blue (RB; VDW, Munich, Germany), TRUShape (TS, Dentsply Tulsa Dental Specialties), XP-endo Shaper (XP; FKG, La Chaux-de-Fonds, Switzerland), iRace (IR, FKG), and TruNatomy (TN; Dentsply Sirona, Ballaigues, Switzerland) in the preparation of moderately curved canals and using micro- computed tomographic technology. Methods: Sixty lower molars with 2 mesial canals were randomly distributed into 6 groups of 10 molars and 20 canals per group (n 5 20). Specimens were scanned before and after preparation using the SkyScan 1275 (Bruker microCT, Kontich, Belgium). Group 1 was treated with WG, group 2 with RB, group 3 with TS, group 4 with XP, group 5 with IR, and group 6 with TN. After instrumentation, researchers quantified the changes produced in the canal geometry in terms of surface, volume, structure thickness, surface convexity index, structure model index, percentage of surface touched, and centroids. Wilcoxon and analysis of variance tests were performed to compare the values before and after preparation and the differences between groups. The significance level was established at 5%. Results: There were no significant differences between WG and RB (P > .05) and between TN and XP (P > .05). TN had significant differences with WG, RB, TS, and IR (P , .05). All the files produced similar apical transportation (P > .05). Conclusions: WG and RB and TN and XP had similar shaping effectivity. TS and WG touched the highest percentages of canal surfaces (81% and 73%, respectively) but produced the biggest changes in the canal anatomy. TN and XP better kept the canal anatomy, but TN touched the lowest percentage of canal surface (50%). All the files used were able to clean and to shape moderately curved canals with minimal apical transportation. (J Endod 2021;47:812-819.)

Objective: The objective of this study was to observe the effect that 3% Sodium Hypochlorite and 17% Ethylenediamine Tetraacetic Acid (EDTA) with water in between, used sequentially and individually had in the disinfection of dentin blocks that were contaminated with Enterococcus faecalis. Materials and Methods: Thirty apical and coronal dentin block samples were divided into five groups (n=5): All samples were inoculated with Enterococcus faecalis Group 1: Samples were submerged in 3% NaOCl then in 17% EDTA. Group 2: Samples were submerged first in 17% EDTA and then in 3% NaOCl. Group 3: Samples were immersed in 3% NaOCl only. Group 4: Samples were submerged in 17% EDTA only. Group 5 (positive control group): Samples were only submerged in distilled water. All samples were submerged in distilled water after each irrigation cycle. The irrigation protocol was repeated in all groups until all dentin samples were exposed to 24ml of the irrigating solutions. CFU units were counted and classified in an ordinal scale and compared with the linear-by-linear association test. Results: A significant linear trend in the reduction of CFU was observed when NaOCl and EDTA were combined (independently of the sequence used) when compared to groups 3 and 4 where the irrigants were used individually both in coronal (p=9.45 x 10-21), and apical slices (p=2.33 x 10-20). NaOCl was significantly more effective than EDTA in both coronal and apical slices (p ≥ 0.000001) when used alone. Conclusion: 3% Sodium Hypochlorite was more effective than 17% EDTA. However, alternating 3% NaOCl with 17% EDTA resulted in better dentinal disinfection. Clinical Relevance: Establishing an irrigation protocol that is effective in eradicating bacteria entrenched in dentinal tubules can lead to a more successful outcome in endodontically treated teeth.

Introduction: Nonsurgical endodontic retreatment continues to be a challenge in endodontics, particularly when dealing with a complex tooth anatomy. This study evaluated the efficacy of passive ultrasonic irrigation (PUI) and the GentleWave system as supplementary techniques to remove remaining filling materials from oval-shaped root canals. Methods: Twenty distal roots of human mandibular molars with single and oval-shaped canals were shaped with R40 (40.06) instrument and filled with gutta-percha and AH Plus sealer using warm vertical obturation. Initial filling material removal was performed with R50 (50.05) instrument, followed by the use of PUI (n = 10) or GentleWave system (n = 10). Microcomputed tomographic images were obtained after obturation, initial material removal, and after the use of PUI and GentleWave. The volume of remaining filling material was calculated for the entire canal as well as for the coronal, middle, and apical thirds. Statistical analyses were performed by using analysis of variance, Kruskal-Wallis and Mann-Whitney tests. P <= .05 was considered significant. Results: The use of PUI and GentleWave as supplementary techniques significantly reduced the volume of remaining filling material after initial instrumentation (P < .05). However, none of these techniques was able to render canals free from filling materials. PUI showed better performance by removing 18% of the remaining filling material, whereas the GentleWave system was able to remove approximately 10% (P = .02). Conclusions: The use of supplementary techniques optimized filling material removal after initial instrumentation. PUI enhanced the overall cleaning of the root canal system during endodontic retreatment in oval-shaped canals.

Cutting efficiency of Reciproc R25 (REC) and Reciproc blue R25 (REB) at different inclinations was evaluated. Sixty new files were tested at 90°, 70° and 45° of inclination in relation to the sample (n = 10), using a customised machine. All files were activated in reciprocation against standardised gypsum blocks for 120 s. Cutting efficiency was determined by measuring the block weight loss with an analytical balance and measuring the length of the block surface cut using a digital calliper. Data were statistically analysed (two-way ANOVA, Bonferroni t-test) with the significance level set at P < 0.05. There was no difference for REC among the tested angles. REB had no statistical difference between 90° and 70°; however, its cutting efficiency significantly increased at 45°. There was a significant difference between REC and REB at 45° only. Under these conditions, increased file inclination to 45° and blue heat treatment improved cutting efficiency of reciprocating files.

Introduction: The aim of this study was to evaluate and compare the shaping ability of XP-endo Shaper (XP; FKG Dentaire, La Chaux-de-Fonds, Switzerland) and TRUShape (TS; Dentsply/Tulsa Dental Specialties, Tulsa, OK) during the preparation of moderated curved root canals using micro-computed tomographic imaging. Methods: Twenty human maxillary premolars with 2 roots were randomly separated into 2 groups of 10 teeth, which were scanned before and after root canal preparation using the SkyScan 1275 X-ray microtomograph (Bruker micro-CT, Kontich, Belgium) at a nominal resolution of <4 mu m. Premolars and irrigant were maintained at 37 degrees before and during preparation; group 1 was treated using XP and group 2 with TS. After preparation, researchers measured the amount of dentin removed, untreated superficies of canal walls, root canal volume, degree of canal transportation, and centering ability. Values of central tendency and dispersion were calculated using Statgraphics Centurion XV software (StatPoint Technologies, Inc, Warrenton, VA); means and median were compared using the Mann-Whitney-Wilcoxon test. The level of significance was set at 5% (P < .05). Results: No significant statistical differences were observed between the 2 groups in shaping ability, untreated superficies of canal walls, degree of canal transportation, and centering ability (P > .05). Conclusions: Instrumentation of moderately curved root canals using the XP single file and the TS file system were equally effective. XP and TS maintained the original anatomy of the root canals and showed a similar percentage of untreated canal walls, centered ability, and minimal apical transportation.

Introduction Increase in efficacy during root canal irrigation may contribute to better treatment outcomes. This study investigated the efficacy of ultrasonic and negative pressure irrigation systems using sodium hypochlorite (NaOCl) in the reduction of bacterial load in human teeth. One hundred thirty-one single-rooted teeth were cleaned and shaped, autoclaved, and incubated with E. faecalis . Teeth were randomly assigned to three experimental groups ( n = 40) and treated in the presence of 1% sodium hypochlorite using EndoUltra cordless ultrasonic, conventional ultrasonic, and Endovac negative pressure irrigation. Syringe irrigation controls were treated with 1% sodium hypochlorite and phosphate-buffered saline via side-vented needle irrigation. All groups with NaOCl received 5% sodium thiosulfate neutralization for 5 min after treatment. Samples of root canal fluid and dentin chips were acquired from canals before and after treatment, incubated on BHI agar, and colony forming units categorized according to quantity. Wilcoxon rank-sum and Bonferroni tests were used for statistical analysis. p values less than 0.05 were considered significant. Results Endovac group was significantly better in eliminating bacteria from the root canals than 1% NaOCl ( p = 0.006) and PBS syringe irrigation ( p = 0.015). However, it was not significantly different from the two ultrasonic groups ( p > 0.05). Both ultrasonic groups showed better performance than 1% NaOCl and PBS syringe irrigation, however, not statistically significant ( p < 0.03). There was no significant difference between the two ultrasonic devices ( p > 0.05). Conclusion EndoVac may be an important tool for bacterial load reduction in oval canals.

BACKGROUND:The purpose of the study was to evaluate the effectiveness of different root canal disinfection techniques in the elimination of a multi-species biofilm from inside the root canal.MATERIAL AND METHODS:Fifty mandibular first premolars were used in the present study, standardized to 11mm of root length, and instrumented with a reciprocation system Reciproc, (VDW GmbH, Munich, Germany) to a #50. Longitudinally sectioned halves of the roots were obtained and washed with NaOCl 4%, EDTA 17% and 5% sodium thiosulfate, and sterilized by autoclaving for 15 minutes at 121°C. A multi-species biofilm broth was developed with three strains of bacteria under laboratory conditions: Enterococcus faecalis ATTC 29212, Eikenella corrodens ATTC 23834, Streptococcus anginosus ATTC 33397. Roots were autoclaved and transferred to the broth for 4 days and then were subjected to either disinfection with sodium hypochlorite 4% and XP-endo Finisher (FKG Dentaire, La Chaux-de-Fonds, Switzerland) or chlorhexidine 2% with and without activation with XP-endo Finisher (FKG Dentaire, La Chaux-de-Fonds, Switzerland).RESULTS:The evaluations of the biofilm elimination showed results that indicate that the 4% sodium hypochlorite group with positive pressure irrigation presented significant differences with the group that had irrigation with sodium hypochlorite activated with XP-endo Finisher and the chlorhexidine groups to 2% (P<0.05).CONCLUSIONS:Chlorhexidine 2% activated with the XP-endo Finisher does not exert elimination or improved cleaning effect on the multi-species biofilm. Activation of sodium hypochlorite 4% improved the elimination of the multi-species biofilm. Key words:Biofilm, multispecies, chlorhexidine, sodium hypochlorite.

BACKGROUND:The aim of this study was to evaluate the effectiveness in dentin debris and smear layer removal from root canal walls using EDTA and QMix® alone and also activated with Nd:YAG laser.MATERIAL AND METHODS:50 single-rooted teeth were instrumented and divided in 5 groups according to irrigation protocol: 17% EDTA, QMix®, Nd:YAG laser alone, and combination of 17% EDTA - Nd:YAG laser and QMix® - Nd:YAG laser. Samples were evaluated using SEM. Statistical analysis was done using Chi-Square Fisher exact test and McNemar test.RESULTS:Dentinal debris analysis showed statistically significant differences when comparing 17% EDTA vs Laser and Laser vs QMix® in combination with Laser at the apical third. The Smear Layer analysis also showed statistically significant differences at the apical third when comparing 17% EDTA vs Laser, QMix® vs QMix® in combination with Laser and Laser vs QMix® in combination with Laser.CONCLUSIONS:17% EDTA was the most efficient irrigant showing the best results. Laser alone was not effective removing either dentinal debris or smear layer. Key words:Laser, endodontics, Smear Layer.

Full Text PDF Images References Journal of Endodontics Volume 38, Issue 1 , Pages 37-40, January 2012 Irrigation Trends among American Association of Endodontists Members: A Web-based Survey Joseph Dutner, DMD , Pete Mines, DDS, Alfred Anderson, DDS Rohde Dental Clinic, US Army Fort Bragg DENTAC, Fort Bragg, North Carolina published online 22 September 2011. Abstract Introduction The purpose of this study was to determine current trends in irrigation selection among endodontists.Introduction The purpose of this study was to determine current trends in irrigation selection among endodontists. Methods An invitation to participate in a web-based survey (QuestionPro) was e-mailed to 3844 members of the American Association of Endodontists. Survey participants were asked between 10 and 14 questions based on their individual responses. Among other questions, participants were asked about their irrigant selection, irrigant concentration, smear layer removal, and use of adjuncts to irrigation. Results A total of 3707 survey invitations were successfully delivered by e-mail after accounting for several undeliverable e-mail invitations. There were 1102 participants, with an overall completion rate of 28.5% (n = 1054). Our data indicate that >90% of respondents primarily use sodium hypochlorite, with 57% of them using it at a concentration >5.0%. Seventy-seven percent of respondents aim to remove the smear layer during endodontic treatment. At least 45% of respondents reported using an adjunct to irrigation. Conclusions Most of the respondents are using full-strength sodium hypochlorite and are routinely removing the smear layer during endodontic treatment. In addition, almost half of the respondents are using an adjunct, such as ultrasonic activation, to aid in their irrigation technique. Print or

Background This study investigated the ability of different irrigation protocols to keep dentinal tubules (DT) open and avoid their blockage by the smear layer (SL) during the cleaning and shaping procedure (CSP). Methods Twenty-five extracted teeth were divided into five groups ( n = 5): group 1, NaOCl was kept in the canal during instrumentation and then washed out with distilled water, and the canal was irrigated with NaOCl with EndoVac in between files; group 2, the same procedure as group 1, but NaOCl was replaced by EDTA; group 3, EDTA was kept in the canal during instrumentation and then washed out with distilled water, and the canal was irrigated with NaOCl with EndoVac in between files; group 4, the same as group 3, but NaOCl and EDTA were alternated; and group 5 (control), the procedure was the same with group 1, but NaOCl was replaced by distilled water. A scanning electron microscope was used to evaluate the cleanliness of DT at three different levels of the canals. Results Groups 3 and 4 showed better ability to keep DT open during CSP than the other groups. Group 4 only showed statistically significant better results than group 3 at middle third ( P < 0.0001). Conclusions Alternating the use of NaOCl and EDTA with water in between can keep DT open better and avoid their blockage by SL during CSP compared with the use of NaOCl or EDTA alone.

Background The purpose of this study was to assess the antimicrobial effect of a buffered 0.5 % sodium hypochlorite solution activated by photon-induced photoacoustic streaming compared to conventional irrigation. Methods The canals on 48 single canal lower bicuspids were cleaned and shaped using rotary instrumentation. All roots were autoclaved for 20 min. Thirty-six of the roots were placed in glass flasks with blood heart infusion media and Enterococcus faecalis (ATCC 4082) for 4 weeks. The remaining 12 roots were placed in a sterile environment and served as negative controls. The contaminated roots were irrigated by conventional means using a buffered 0.5 % sodium hypochlorite solution with or without photon-induced photoacoustic streaming (PIPS) activation ( n = 12 each group). The remaining 12 roots did not receive any treatment and served as positive controls. The apical 3 mm of each tooth was sectioned and pulverized. The pulverized samples were collected and placed in Eppendorf micro-centrifuge tubes with sterile phosphate-buffered saline. Thirty MicroLiters of the collected samples was then placed in the blood heart infusion media and incubated for 24 h at 37 °C. Colony forming units (CFU) were compared with Wilcoxon signed ranked test. Mann-Whitney U test was used to assess PIPS effectiveness in comparison with conventional irrigation. Results Both regimens reduced significantly the number of CFU; however, reduction was significantly higher for the PIPS group ( p = 0.002). Conclusion Buffered 0.5 % sodium hypochlorite delivered by conventional method was effective in removing E. faecalis from contaminated root canals; however, activation of a buffered 0.5 % sodium hypochlorite solution by PIPS significantly increased its antimicrobial capacity.