Cleaning and Disinfecting Oval-Shaped Root Canals: Ex Vivo Evaluation of Three Rotary Instrumentation Systems with Passive Ultrasonic Irrigation.

Background and Objectives: Successful root canal treatment depends on the thorough removal of biofilms through chemomechanical preparation. This study aimed to investigate and compare the cleaning and disinfecting efficiency of oval-shaped root canals using XP-endo Shaper (XPS), ProTaper Next (PTN), and HyFlex CM (HCM) in combination with passive ultrasonic irrigation (PUI). Materials and Methods: Ninety extracted teeth were contaminated and randomly divided into three groups: XPS, PTN, and HCM. Each group was assigned to three subgroups: subgroup A (sterile saline), subgroup B (3% sodium hypochlorite and 17% ethylenediaminetetraacetic acid), and subgroup C (3% sodium hypochlorite, 17% ethylenediaminetetraacetic acid, and PUI). Bacterial sampling was conducted both from baseline samples and samples after chemomechanical preparation. Scanning electron microscopy (SEM) was used to evaluate the residue bacterial biofilms, hard tissue debris, and smear layers on the buccolingual walls of oval-shaped root canals. Results: When combined with sterile saline, XPS demonstrated a higher reduction of bacterial counts and was more effective in eradicating Enterococcus faecalis in the middle third of the canals compared to the other instruments (p < 0.05). Additionally, when used with antimicrobial irrigants, XPS was more effective in disinfecting the coronal third of the canals than the other instruments (p < 0.05). Furthermore, XPS reduced hard tissue debris more effectively in the middle third of canals than in the apical third (p < 0.05). Conclusions: XPS outperforms PTN and HCM in disinfecting oval-shaped root canals. Despite the fact that combining XPS and PUI improves cleaning and disinfecting, removing hard tissue debris from the critical apical area remains challenging.

The Effectiveness of Different Irrigation Techniques on Debris and Smear Layer Removal in Primary Mandibular Second Molars: An In Vitro Study.

AIMS: The aim of the present in vitro study was to compare the effectiveness of passive ultrasonic irrigation (PUI), sonic irrigation, and mechanic dynamic activation on the removal of debris and smear layer from primary mandibular second molars during pulpectomy. MATERIALS AND METHODS: Mesial roots of 48 primary mandibular second molars were prepared with an R-motion 21 mm file (30/0.04) (FKG Dentaire SA, La Chaux-de-Fonds, Switzerland), irrigated with 1% sodium hypochlorite (NaOCl) and 17% ethylenediaminetetraacetic acid (EDTA), and divided into four groups (n = 24 canals) according to the final irrigation activation technique: control group without activation, PUI with Ultra-X (Eighteeth, Changzhou, China), mechanical activation with XP-endo Finisher (FKG), and sonic irrigation with EQ-S (Meta Biomed, Chungcheongbuk-do, Korea). The roots were split longitudinally and analyzed using scanning electron microscopy (SEM). The presence of debris and smear layer was assessed using a 5-grade scoring scale with 200× and 1000× magnification, respectively. The Kruskal-Wallis and Friedman tests were used for data analysis. RESULTS: The activation of the irrigant significantly improved debris and smear layer removal (p < 0.001). There was no significant difference between Ultra-X, XP-endo Finisher, and EQ-S (p > 0.05). No activation technique was able to completely eliminate debris and smear layer from the root canals of primary mandibular second molars. CONCLUSIONS: During pediatric pulpectomy, the irrigation protocol must include activation of the irrigation solutions using either ultrasonic, sonic, or mechanical activation techniques to enhance the removal of debris and smear layer for a better prognosis. CLINICAL SIGNIFICANCE: During root canal treatment on primary teeth, the clinician must incorporate an activation technique in the irrigation protocol to enhance the removal of debris and smear layer and increase the success of the treatment.

Passive ultrasonic irrigation in root canal: systematic review and meta-analysis.

OBJECTIVE: To investigate whether there are differences between the root canal disinfection, comparing the passive ultrasonic irrigation technique with the conventional technique. MATERIALS AND METHODS: The following electronic databases were searched: Pubmed; VHL; Web of Sciences and OVID with no publication date restriction. The study's quality evaluation was carried out using the Handbook by Cochrane. The online research identified 5464 studies. From the nine studies selected for a full reading of the text, five were included in the present systematic review. Meta-analysis was performed in three articles, which evaluated the root canal's cleanness through microbiological analysis. RESULTS: Only one article concluded that the ultrasonic passive irrigation showed a better performance compared with the conventional irrigation. None of the articles analyzed presented a low risk of bias in all domains. According to the results of the meta-analysis, there was no statistical difference between the groups (OR = 0.34, IC 95%: 0.10-1.19). CONCLUSIONS: The level of evidence comparing the two techniques is fragile since in all studies some type of bias was observed which may interfere in the results and conclusions.

Immediate endodontic access cavity sealing: fundamentals of a new restorative technique.

Endodontic access cavity sealing is conventionally performed after endodontic irrigation, referred to as delayed endodontic sealing (DES). Evidence shows that endodontic irrigation with NaOCl decreases dentinal bond quality and could cause coronal leakage. Access cavity sealing before endodontic irrigation is a new restorative approach, referred to as immediate endodontic sealing (IES). The primary aim of this in vitro study was to investigate whether IES improved internal adaptation. The secondary aim was to investigate the influence of the viscosity of the composite used to seal the dentine, on the internal adaptation in both IES and DES groups. Third molars (n= 40) with fully developed apices were used. The teeth were prepared into standard Class II MO cavities, and divided in 4 groups according to the approach, and composite viscosity was used for sealing. Group 1: IES + low viscosity composite; group 2: IES + high viscosity composite; group 3: DES + low viscosity composite; and group 4: DES + high viscosity composite. Samples were then sectioned axially for observation using scanning electron microscopy. Outcome was evaluated by determining the internal adaptation of the samples, which was judged based on the percentage of a continuous margin at the tooth-composite interface. The results were analyzed using a two-way analysis of variance and Mann-Whitney test. IES groups exhibited significantly greater internal adaptation (p = 0.000) as compared with DES groups. Composite viscosity did not significantly affect internal adaptation in either IES or DES groups (p > 0.005).

Assessment of 2'-Fucosyllactose and Lacto-N-Neotetraose Solution as an Irrigant in E. faecalis-Infected Root Canals: An In Vitro Study.

BACKGROUND: Given the lack of an ideal endodontic irrigant on the market, this study evaluates the antimicrobial potential of a formulated solution of 2'-fucosyllactose and lacto-N-neotetraose against E. faecalis within infected root canals, and explores any associated impacts related to the duration of irrigation. METHODS: 32 single-rooted teeth extracted for periodontal reasons were infected with Enterococcus faecalis, and subsequently subjected to endodontic treatment with two different irrigation systems: sodium hypochlorite or a solution of 2'-fucosyllactose and lacto-N-neotetraose. These samples were then incubated in sterile culture media at 37 °C to observe microbial activity through turbidity. The culture broth of each individual sample was assessed as positive or negative by observing the turbidity or lack of turbidity in the culture at the time of evaluation. RESULTS: the analysis of the results obtained from the comparison of groups irrigated with sodium hypochlorite or a solution of 2'-fucosyllactose and lacto-N-neotetraose demonstrates that the case solution has no bactericidal effect against E. faecalis inoculated in the endodontic system. CONCLUSIONS: the HMOs used in this study do not have a bactericidal effect on E. faecalis inoculated in an endodontic system.

Improving the Antimicrobial Potency of Berberine for Endodontic Canal Irrigation Using Polymeric Nanoparticles.

To address the challenges posed by biofilm presence and achieve a substantial reduction in bacterial load within root canals during endodontic treatment, various irrigants, including nanoparticle suspensions, have been recommended. Berberine (BBR), a natural alkaloid derived from various plants, has demonstrated potential applications in dentistry treatments due to its prominent antimicrobial, anti-inflammatory, and antioxidant properties. This study aimed to produce and characterize a novel polymeric nanoparticle of poly (lactic-co-glycolic acid) (PLGA) loaded with berberine and evaluate its antimicrobial activity against relevant endodontic pathogens, Enterococcus faecalis, and Candida albicans. Additionally, its cytocompatibility using gingival fibroblasts was assessed. The polymeric nanoparticle was prepared by the nanoprecipitation method. Physicochemical characterization revealed spheric nanoparticles around 140 nm with ca, -6 mV of surface charge, which was unaffected by the presence of BBR. The alkaloid was successfully incorporated at an encapsulation efficiency of 77% and the designed nanoparticles were stable upon 20 weeks of storage at 4 °C and 25 °C. Free BBR reduced planktonic growth at ≥125 µg/mL. Upon incorporation into PLGA nanoparticles, 20 µg/mL of [BBR]-loaded nanoparticles lead to a significant reduction, after 1 h of contact, of both planktonic bacteria and yeast. Sessile cells within biofilms were also considered. At 30 and 40 µg/mL, [BBR]-loaded PLGA nanoparticles reduced the viability of the sessile endodontic bacteria, upon 24 h of exposure. The cytotoxicity of BBR-loaded nanoparticles to oral fibroblasts was negligible. The novel berberine-loaded polymeric nanoparticles hold potential as a promising supplementary approach in the treatment of endodontic infections.

Sealing of pulp chamber dentin in endodontics: Influence of bond strategy and time-point application.

Context: Seal the dentin of the pulp chamber during endodontic treatment to avoid interfering with the restorative treatment performed afterward. Aims: The aim was to evaluate the effect of three adhesive systems applied in different bonding strategies (etch-and-rinse, self-etch, and universal adhesive) and time-point application (immediately after the cavity access preparation or after endodontic obturation) on the hybrid layer formation and dentinal penetrability. Materials and Methods: Forty-eight sound molars were randomly distributed into six groups (n = 10) according to the adhesive system used: Forty-eight sound molars were randomly distributed into six groups (n = 10) according to the adhesive system used and the time-point application: Adper Scotchbond Multi-purpose (AS), Clearfil SE (CF) and Scotchbond Universal (SU) in strategy of immediate endodontic sealing (IES) or delayed endodontic sealing (DES). In IES-AS, IES-CF, and IES-SU groups, dentin sealing was performed immediately after the cavity access, while in DES-AS, DES-CF, and DES-SU, after root canal obturation. The specimens were sectioned in the long axis, in a buccal-lingual direction, and the dentinal penetrability of the adhesive systems was evaluated using confocal microscopy images. Hybrid layer formation was analyzed by scanning electron microscopy images. Statistical Analysis Used: Dentinal penetrability data were analyzed with the ANOVA test and the Kruskal-Wallis test was performed for hybrid layer data (α = 0.05). Results: IES-CF showed the lowest dentinal penetrability (P < 0.05), while the other protocols were similar to each other (P > 0.05). No significant differences were found between groups regarding the hybrid layer formation (P > 0.05). Immediate and DES protocols do not influence the hybrid layer formation, regardless of the bond strategy used. Conclusions: Sealing the pulp chamber dentin before endodontic treatment can improve the bond strength of the final restoration but the formation of the hybrid layer was not influenced by the bond strategy.

Effects of endodontic root canal irrigants on tooth dentin revealed by infrared spectroscopy: a systematic literature review.

BACKGROUND: Root canal irrigation endodontic solutions have effects on the chemistry of dentin. Infrared spectroscopy is a non-destructive chemical characterization method where the strength of absorption often correlates with mineral or organic composition. OBJECTIVES: To survey effects of commonly used irrigation solutions on the composition of root dentin as detected by widely-available Fourier transform infrared spectroscopy (FTIR) methods. METHODS: Electronic databases were searched for articles published between 1983 to 2023. After risk of bias assessments (OHAT), studies were grouped according to effects per irrigation solution. Inclusion criteria comprised in vitro studies that used extracted human or bovine teeth, treated by irrigation solutions characterized using FTIR spectroscopy and presenting spectral data. Publications that did not present spectra were excluded. RESULTS: A wide range of concentrations, durations, and treatment protocols have been tested but only 30 out of 3452 studies met our inclusion criteria. Different FTIR methods were used with Attenuated Total Reflection (ATR) variant being the most common (21 studies). Investigated solutions included sodium hypochlorite (NaOCl), ethylenediaminetetraacetic-acid (EDTA), 1-hydroxyethylidene-1-1-diphosphonic-acid (HEDP), peracetic-acid (PAA), glycolic-acid (GA), and citric-acid (CA) though most focused on NaOCl and EDTA. All solutions had detectable effects in the FTIR signature of dentin. NaOCl mainly affects the organics, revealing reduced amide/phosphate ratios with increasing concentrations. EDTA mainly effects the inorganic component, with the effects increasing with time and concentration, yet glycolic acid has stronger effects than EDTA on dentin. Beyond the type of irrigant and dentin exposure durations, concentration and protocol of application had strong effects. There is a lack of studies comparing similar irrigants under conditions that mimic clinical scenarios analyzing bulk sample because FTIR of powder dentin differs from FTIR of bulk dentin. SIGNIFICANCE: The ideal root-canal irrigant should combine local disinfection properties with minimal compositional effects on healthy dentin. FTIR methods appear reliable to identify important changes in root dentin chemical composition. Such information can help understand when endodontic irrigation might lead to root degradation or possibly contribute to long term failures such as vertical fractures. Awareness of chemical damage from irrigation procedures may help clinicians select procedures that reduce deleterious effects on the root canal structures.

Effect of the Irrigation Agitation Technique on Postoperative Pain in Teeth With Symptomatic Irreversible Pulpitis.

Introduction Irrigation of the root canal system is a vital step in endodontic treatment aimed at disinfecting the canal. The efficacy of irrigation can be improved by various irrigation agitation methods. One such novel method of interest is the manual dynamic agitation (MDA) technique. However, the effect of MDA on postoperative pain as compared to needle irrigation (NI) with sodium hypochlorite has been scarcely explored. This study aimed to compare the effects of NI and MDA techniques on postoperative pain in teeth with symptomatic irreversible pulpitis. Materials and methods This quasi-experimental study was conducted at the Department of Operative and Paediatric Dentistry, Fauji Foundation Dental Hospital, over four months after gaining ethical approval. One hundred and sixty-eight participants diagnosed with symptomatic irreversible pulpitis were enrolled in the study through the purposive sampling technique. The participants were divided into two groups based on the irrigation technique used: Group A (NI) and Group B (MDA). Postoperative pain was recorded after six hours, 24 hours, 48 hours, and seven days using the 0-100mm visual analog scale (VAS). The VAS scores were compared using an independent sample t-test. Results Out of 168 participants, 48.2% were in Group A and 51.2% in Group B. The study found that VAS pain scores for Group B (MDA) were significantly lower at six hours, 24 hours, 48 hours, and seven days as compared to Group A (NI), with a p-value less than 0.001. Conclusion This study shows that the MDA technique leads to decreased postoperative pain both immediately after endodontic treatment and a week later as compared to the NI technique. Hence, the use of MDA can aid in controlling postendodontic pain and, therefore, ensure smoother recovery and increased patient satisfaction.

Evaluating the Impact of Ultrasonic Irrigation on Bacterial Levels and Activity Following Chemomechanical Procedures.

AIM: This single-arm interventional trial aimed to investigate the efficacy of ultrasonic irrigation as a supplementary disinfection approach after chemomechanical procedures using molecular techniques based on ribosomal RNA (rRNA) and rRNA genes (referred to as DNA). METHODOLOGY: Samples were collected from 35 single-rooted teeth with radiographic evidence of apical periodontitis. Samples were taken after gaining root canal access (S1), chemomechanical procedures (CMP, S2), and ultrasonic irrigation (S3). DNA-targeted qPCR using universal primers was used to estimate total bacterial levels, while rRNA-targeted qPCR was used to assess bacterial activity. Ratios between rRNA and DNA levels were calculated to search for active bacteria in the samples (rRNA/ DNA ≥ 1). Wilcoxon matched-pairs signed-rank test was used to compare the differences in DNA levels between samples and DNA and rRNA levels within samples (P <.05). RESULTS: DNA-based methods revealed a significant decrease in bacterial levels from S1 to S2 and S2 to S3 (both P <.05). Notably, 11 out of 35 (31.4%) root canals did not harbor bacterial DNA after CMP, whereas ultrasonic activation increased DNA-negative samples to 17 (48.6%). However, all DNA-positive samples were also positive for rRNA, with significantly higher rRNA than DNA levels (P <.05), indicating bacterial activity at the sampling time. CONCLUSIONS: Ultrasonic irrigation improved the disinfection of root canals after chemomechanical procedures by reducing bacterial levels. However, persisting bacteria remained active in the root canals after CMP and ultrasonic irrigation.

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.

Flow characteristics of positive and negative pressure irrigation in an immature tooth - A computational fluid dynamics study.

Aim: This study aims to investigate the irrigation dynamics in an immature tooth during positive and negative pressure irrigation using a computational fluid dynamics (CFDs) model. Materials and Methods: Cone-beam computed tomography scan of the maxillary central incisor with Cvek's stage III root development was used for the reconstruction of the root canal geometry. The computer-aided design models of open (front vent and notched) and closed (side vent [SV]) needles were positioned inside the root canal at two penetration depths, i.e., 3 mm and 1 mm short of apex. The negative pressure microcannula (MiC) was positioned at the level of the root apex. A prevalidated CFD model was used to simulate endodontic irrigation. Results: The irrigant velocity in the apical root canal beyond the needle tip exceeded 0.1 m/s. As the needles were positioned closer to the apex, the wall shear stress (WSS) increased for the open-ended needles and decreased for the SV needle. MiC produced the lowest WSS. The mean apical pressure produced by the SV needle and MiC were below the critical threshold for periapical extrusion. Conclusions: The SV needle inserted within 1-3 mm of root apex during endodontic irrigation in an immature tooth allows adequate irrigant exchange with minimal risk of periapical extrusion.

Comparison of smear layer removing efficacy of Cold Atmospheric Pressure (CAP) Plasma Jet with different chelating agents. An ex-vivo study.

The present study aimed to assess the effectiveness of different final irrigation regimens (Cold Atmospheric Pressure Plasma Jet, MTAD, and EDTA) in removing the smear layer from intra-radicular dentin using a Scanning Electron Microscope (SEM). Eighty-four mandibular premolars were prepared with ProTaper Universal hand files and were equally divided into four groups i.e. Normal saline (control), EDTA, MTAD and CAP Plasma Jet. Prepared samples in the control, EDTA and MTAD groups were irrigated with 5 milliliters of the irrigant, and it was retained for 2 min. In the CAP Plasma Jet group, the plasma plume was directed towards the canal lumen for 2 min. The smear layer removal of all the groups was evaluated at the coronal, middle and apical thirds. Statistical analysis was performed using Kruskal-Wallis test followed by Dunn's test. Evaluation by SEM showed that the smear layer removal ability of MTAD and EDTA were significantly better than CAP Plasma Jet (p < 0.05). While CAP Plasma Jet showed results comparable to EDTA in the coronal third. In the middle and apical third of the canal, its effect was comparable to the control group (p > 0.05). MTAD and EDTA aided in better smear layer removal than the CAP Plasma Jet in the coronal, middle, and apical third of the test samples. CAP Plasma jet performed better in the coronal third.

Influence of Needle Design and Irrigant Flow Rate on the Removal of Enterococcus faecalis Biofilms In Vitro.

This study aimed to evaluate the influence of needle design and irrigant flow rate on the removal of Enterococcus faecalis mature biofilms during sodium hypochlorite irrigation. Forty-eight single-rooted human teeth were instrumented (ProTaper F3), autoclaved and inoculated with Enterococcus faecalis to establish a two-week-old biofilm. E. faecalis biofilms were treated with Sodium hypochlorite that was injected in the root canals using three types of needles (NaviTip, ProRinse, IrriFlex). For the IrriFlex needle, one, two, or four bars of pressure was applied to the irrigating solution to increase flow rates. Bacteria were labeled with the LIVE/DEAD BacLight Bacterial Viability kit, and viability was assessed by flow cytometry (FCM). Results were statistically analyzed using one-way ANOVA and Tukey multiple comparison intervals (α = 0.05). Bacterial viability was significantly reduced after sodium hypochlorite passive irrigation but the number of viable bacteria retrieved from root canal specimens irrigated with the Pro-Rinse needle was significantly higher compared to NaviTip and IrriFlex needles (p < 0.05). When the irrigant flow rate was increased, the viability of bacterial biofilms was significantly reduced compared to passive irrigation using the IrriFlex needle (p < 0.05). Applying higher flow rates during irrigation using the IrriFlex needle did not further reduce bacterial viability.

Assessment of Bacterial Load Using 3.8% SDF as an Irrigant in Pulpectomized Primary Molars: A Randomized Controlled Trial.

Aim and objective: The aim of the present study was to evaluate the reduction in bacterial loading using 3.8% as an irrigating solution in pulpectomized primary molars. Study design: A randomized, controlled clinical trial was performed that included primary molars with pulp necrosis. Sixty necrotic canals were included, 30 irrigated with 3.8% SDF (experimental group) and 30 with 1% NaOCl solution (control group); in all cases, two microbiological samples from within the canals were taken with sterile paper points, the first after the canal opening and before the first irrigation, and the second after instrumentation and final irrigation, before obturation. All samples were evaluated by Agar plate method. Results: The results were statistically analyzed by student "t" test. After analyzing samples before and after irrigation in the control group (NaOCl), we found a strong significant decrease of bacterial load (p = < 0.001). The same occurred in the 3.8% SDF group samples (p = < 0.001). When both groups were compared post irrigation, a statistically significant difference was observed in favor of 3.8 % SDF. Conclusion: 3.8% SDF can be suggested as an alternative irrigant for pulpectomy of necrotic teeth. How to cite this article: Maru V, Padawe D, Naik S, et al. Assessment of Bacterial Load Using 3.8% SDF as an Irrigant in Pulpectomized Primary Molars: A Randomized Controlled Trial. Int J Clin Pediatr Dent 2022;15(S-1):S47-S51.

Evaluation of resin sealer penetration of dentin following different final rinses for endodontic irrigation using confocal laser scanning microscopy.

The aim of the study was to assess the depth of sealer penetration into dentinal tubules following different final rinses and indirectly evaluate precipitation of irrigating solutions. Methods: 52 extracted maxillary incisors were prepared to size 40/04 with 6% sodium hypochlorite irrigating solution. Following power analysis, teeth were randomly divided into 4 groups (n = 13) according to final rinse. Group 1 - 17% EDTA, Saline and 2% Chlorhexidine solution; Group 2 - SmearOFF™; Group 3 - Qmix® ; and Group 4 - saline control. Obturation was performed with gutta percha and resin sealer mixed with rhodamine-B-isothiocyanate dye using warm vertical compaction. Teeth were sectioned into apical, middle, and coronal thirds using Buehler diamond saw at 3, 6 and 9 mm from the apex. Sections were examined under confocal laser scanning microscopy, and images were exported to Image J software to measure the maximum depth of sealer penetration circumferentially. Data were analysed using a generalised linear model and post hoc multiple comparisons with significance set at P < 0.05. Group 3 had the highest depth of penetration. There were statistically significant differences between Groups 2 and 3 and control for all sections, Group 1 and control in apical section only. Conclusion: Recently developed final rinses produced higher sealer penetration and more patent dentinal tubules than using EDTA and chlorhexidine sequentially.

Multiple assessment methodologies in determining the antibiofilm actions of sodium hypochlorite mixed with clodronate or etidronate in endodontic irrigation.

This study aimed to use multiple methodologies, including a novel usage of scanning electron microscopy (SEM), to evaluate the antimicrobial actions of sodium hypochlorite (NaOCl) admixed with clodronate or etidronate in root canal irrigation. The study also examined the usefulness of colony counting as a biofilm assessment methodology. Seven day Enterococcus faecalis biofilms were grown on hydroxyapatite discs. The discs were disinfected with 0.26 M clodronate-5% NaOCl, 0.26 M etidronate-5% NaOCl, 5% NaOCl, or treated with phosphate buffered saline (PBS). Assessments were performed using colony counting, SEM and the XTT reduction assay. The XTT assessment used the same groups but with 2.5% NaOCl. For colony counting, bacteria were removed from the discs by vortex mixing, followed by plating. The discs were subsequently fixed for SEM imagining and evaluators scored the SEM micrographs for remaining bacteria. Antibiofilm actions were assessed with the Kruskal-Wallis and Dunn's multiple comparison tests. SEM micrographs and the XTT assay revealed no differences between the NaOCl controls and the clodronate or etidronate mixtures with NaOCl (P > 0.05). It was concluded that the chelator mixtures with NaOCl had antibiofilm actions comparable to NaOCl. Furthermore, vortex mixing incompletely removed biofilm from HA discs in the PBS controls and hence colony counting using E. faecalis biofilms on hydroxyapatite discs could not be used for intergroup comparisons involving PBS. Additionally, colony counting could not be used for comparisons between the NaOCl treatment groups because the removal of bacteria from the substrate by vortex mixing was affected by the irrigant type.

Volumetric Analysis of Irrigant Extrusion in Immature Teeth after Different Final Agitation Techniques.

INTRODUCTION: The aim of this study was to evaluate the volume of irrigant extrusion by different final agitation techniques in experimental models of immature teeth. METHODS: Fifteen single roots of mandibular premolars with a length of 14 mm and an open apex were used to form 6 groups according to the final agitation technique: group 1, positive pressure and no agitation; group 2, ultrasonic agitation with Irrisonic (Helse Dental Technology, Santa Rosa de Viterbo, Brazil); group 3, ultrasonic agitation with Irrisonic Power (Helse Dental Technology); group 4, mechanical agitation with Easy Clean (Easy Dental Equipment, Belo Horizonte, Brazil); group 5, mechanical agitation with XP-endo Finisher (FKG Dentaire, La Chaux-de-Fonds, Switzerland); and group 6, sonic agitation with Eddy (VDW, Munich, Germany). A prototype was made from an Eppendorf plastic tube filled with agar to fix the tooth and to collect the extruded irrigant. Ioditrast 76 (Justesa Imagen Mexicana, Tlalpan, Mexico) contrast solution was used to simulate the irrigant. The volume of irrigant extruded in cubic millimeters was calculated by micro-computed tomographic imaging. Data were analyzed using Kruskal-Wallis and Dunn tests with a significance level of 5%. RESULTS: The values for the volume of irrigant extruded were as follows: 0.67 (group 5), 0.76 (group 1), 2.28 (group 2), 3.14 (group 3), 3.15 (group 4), and 17.19 (group 6). There was a statistically significant difference (P < .05) when the values of group 6 were compared with those of the other groups. CONCLUSIONS: All techniques caused irrigant extrusion. The higher extrusion values occurred when sonic agitation was performed with the Eddy instrument.

The Efficiency of the Er: YAG Laser and PhotonInduced Photoacoustic Streaming (PIPS) as an Activation Method in Endodontic Irrigation: A Literature Review.

In the field of endodontics, lasers have been used for a long time for the optimization of Endodontic irrigation in particular. The laser-activated irrigation (LAI) technique is based on the photomechanical effects of the lasers at low settings. They create specific cavitation phenomena and acoustic streaming in intracanal fluids. More recently, a new technique with a Er:YAG laser has been used with sub-ablative energy (20 mJ, 15 Hz) and ultra-short pulses (50 µs). This leads to intracanal cavitation and shockwaves as a result of photoacoustic and photomechanical effects. This phenomenon is called photon-induced photoacoustic streaming (PIPS). PIPS and Laser activated irrigation are described in the literature as a revolutionary and powerful method to activate the irrigant; however, systematic literature on this topic is missing. This review compares the literature on Er:YAG LAI and PIPS on endodontic irrigation with other irrigation methods. An article search was performed on the PubMed database using a series of keywords related to endodontic irrigation, including Er:YAG LAI and PIPS; 59 articles were selected for the review according to the inclusion and exclusion criteria. No in vivo study was found. The Er:YAG LAI and PIPS outperformed other methods in 33 of the 59 articles. There was a great variety in the study designs including bacterial incubation time, laser parameters, irrigation protocols, and irrigating solution used. The evidence suggests that the Er:YAG LAI and PIPS are promising in canal disinfection as well as debris and smear layer removal. However, the large variety in the study methods makes the results less significant. Further studies are needed to better evaluate the efficiency of these techniques, especially in vivo studies.

Effects of Contemporary Irrigant Activation Schemes and Subsequent Placement of an Interim Dressing on Bacterial Presence and Activity in Root Canals Associated with Asymptomatic Apical Periodontitis.

New tools for activating endodontic irrigants have evolved, yet their impact on root canal disinfection, in comparison to the passive placing of an inter-visit medication, have not yet been fully elucidated. The use of DNA- and rRNA-based methods may cast some new light on this issue, as they allow a comparison to be made between microbial presence and activity. Therefore, the aim of this single-arm intervention trial is to evaluate the antibacterial effect of endodontic procedures using both molecular methods. Root canal samples were obtained from 20 patients with asymptomatic apical periodontitis after each treatment step: access cavity, chemo-mechanical preparation, adjunctive procedures (XP-endo Finisher file and passive ultrasonic irrigation), calcium hydroxide medication, and 2nd-visit root canal preparation. DNA and cDNA from the samples were subjected to quantitative polymerase chain reaction with universal primers for the bacterial 16S rRNA gene. Chemo-mechanical preparation promoted a drastic reduction in bacterial levels and activity, whereas the adjunctive procedures did not make a significant contribution to further disinfection. At the 2nd visit, bacteria were active after the use of calcium hydroxide medication; however, they were significantly reduced after a 2nd-visit preparation. Consequently, the lowest bacterial levels were found at the end of the treatment. This clinical trial, which used an rRNA and rDNA combined approach, confirmed previous studies showing that root canal preparation represents the main strategy for root canal disinfection.